Datasheet LED driver series for LCD back light White LED driver for medium sized and large sized LCD back light BD9470AEFVBD9470AFM General Description BD9470AEFV and BD9470AFM are high efficiency driver for white LED. They are designed for large sized LCD. BD9470AEFV and BD9470AFM are built-in DCDC converter that supply appropriate voltage for light source. BD9470AEFV and BD9470AFM are also built-in protection function for abnormal state such as OVP: over voltage protection, OCP: over current limit protection of DCDC, SCP: short circuit protection, open detection of LED string. Thus they are used for conditions of large output voltage and load conditions. Features 6ch LED constant current driver LED maximum output current 250mA Individual PWM dimming modulation allowed for LEDs 2% LED current accuracy (when each LED is set to 130mA) Built-in LED feedback voltage automatic adjustment circuit according to LED current Built-in start-up circuit independent of PWM light modulation built-in VOUT FB voltage maintenance function when PWM=Low0% Built-in LED current stabilization circuit while scanning operation is performed Built-in VOUT discharge circuit while shutdown Built-in LED protection (OPEN / SHORT protection) Individual detection and individual LED OFF for both open and short circuit Adjustable LED short-circuit protection threshold PWM-independent LED protection VOUT over voltage protection (OVP) and reduced voltage protection (SCP) circuit Built-in failure indication function Built-in ISET pin short-circuit protection circuit Key Specifications VCC supply Voltage range: 9.0V35.0V LED minimum output current: 40mA LED maximum output current: 250mA DCDC oscillation frequency: 150KHz(RT=100Kohm) Operation circuit current: 6mA(typ.) Operating temperature range: -4085 Applications LED driver for TV, monitor and LCD back light Package HSOP-M28 HTSSOP-B28 W (Typ.) x D(Typ.) x H(Max.) 18.50mm x 9.90mm x 2.41mm 9.70mm x 6.40mm x 1.00mm Figure 1. HSOP-M28 Typical Application Circuit VIN ISET PWM FAIL SS PWM1 FB PWM2 RT PWM3 DCDC_GND PWM4 N PWM5 CS PWM6 REG58 GND VCC FAIL STB OVP LSP LED6 UVLO LED5 LED1 LED4 LED2 LED_GND LED3 Figure 2. HTSSOP-B28 STB Figure 3. Typical Application Circuit Product structureSilicon monolithic integrated circuit This product is not designed protection against radioactive rays www.rohm.com TSZ02201-0F10C1002000-1-2 (c) 2013 ROHM Co., Ltd. All rights reserved. 1/35 TSZ2211114001 19.Oct.2013 Rev.003 BD9470AFMBD9470AEFV 1. Specification for BD9470AEFVBD9470AFM Absolute Maximum Ratings (Ta=25C) Parameter Symbol Rating unit VCC -0.3~36 V OVP Detect Voltage (DCDC Stop) LED1~6 -0.3~40 V STB,FAIL,UVLO,OVP -0.3~36 V ISETFBSS CSNREG58RT pin voltage ISETFBSSCSNREG58RT -0.3~7 V PWM1~6LSP Power dissipation (HSOP-M28)*1 PWM1~6LSP Pd -0.3~16 5208 mW Pd 4700 mW LED1~6 pin voltage STBFAILUVLOOVP pin voltage Power dissipation (HTSSOP-B28)*2 Operating temperature range Topr -40+85 Storage temperature range Tstg -55+150 Tjmax +150 Symbol Rating unit VCC 9.0 35.0 V Maximum junction temperature *1 Decreases -41.7mW/C at Ta=25C or higher (When mounting a four-layer 70.0mmx70.0mmx1.6mm board) *2 Decreases -37.6mW/C at Ta=25C or higher (When mounting a four-layer 70.0mmx70.0mmx1.6mm board) Recommended Operating Ratings Parameter Supply voltage LED1-4 pin minimum output current ILED_MIN 40 mA*1 LED1-4 pin maximum output current ILED_MAX 250 mA*1*2*3 LSP input voltage range VLSP 0.32.5 V fsw 100 500 kHz PWM_MIN 30 S DC/DC oscillation frequency Min. on-duty for PWM light modulation *1 The amount of current per channel If LED makes significant variations in its reference voltage Vf, the driver will increase power dissipation, resulting in a rise in package *2 temperature. To avoid this problem, design the board with thorough consideration given to heat radiation measures. *3 The LED current can be set up to 250mA Pin Configuration ( TOP VIEW ) ISET PWM1 PWM2 PWM3 PWM4 PWM5 PWM6 1 2 3 4 5 6 7 28 27 26 25 24 23 22 Outline Dimension Diagrams/Sign Diagrams LOT No. SS FB RT DCDC_GND N CS REG58 BD9470AFM GND FAIL OVP LED6 LED5 LED4 LED_GND 8 9 10 11 12 13 14 21 20 19 18 17 16 15 VCC STB LSP UVLO LED1 LED2 LED3 LOT No. 1.REG58 2.CS 3.N 4.DCDC_GND 5.RT 6.FB 7.SS 8.ISET 9.PWM1 10.PWM2 11.PWM3 12.PWM4 13.PWM5 14.PWM6 28.VCC 27.STB 26.LSP 25.UVLO 24.LED1 23.LED2 22.LED3 21.LED_GND 20.LED4 19.LED5 18.LED6 17.OVP 16.FAIL 15.GND BD9470AEFV Figure 4. Pin ConfigurationTOP VIEW www.rohm.com (c) 2013 ROHM Co., Ltd. All rights reserved. TSZ2211115001 Figure 5. Outline Dimension Diagrams/Sign Diagrams 2/35 TSZ02201-0F10C1002000-1-2 19.Oct.2013 Rev.003 BD9470AFMBD9470AEFV Contents 1. Specification for BD9470AEFVBD9470AFM P2P9 P2 P2 P2 P2 P4,P5 P6 P6 P7 P8 P8,P9 Absolute Maximum Ratings Recommended Operating Ratings Pin Configuration Outline Dimension Diagrams/Sign Diagrams Electrical Characteristics Pin Numbers, Names, and Functions External Component Recommended Range Internal Equivalent Circuit Diagrams Block Diagram Characteristic date 2. Understanding BD9470AEFVBD9470AFM P10P12 P10P12 Pin Functions 3. Application of BD9470AEFVBD9470AFM P13P32 3.1 BD9470AEFV, BD9470AFM examination for application P13P27 P13,P14 P15 P16 P17,P18 P19,P20 P21,P22 P23 P23 P24 P25 P26 P27 Start-up and SS capacity setting explanation The setting of REG58 capacity and shutdown procedure VCC series resistance setting procedure The necessity for holding output voltage and FB voltage while PWM=Low Explanation of VOUTOVP voltage holding function when PWM=Low FB current Source modeSink/Source mode LED Current setting DC/DC converter drive frequency setting UVLO setting procedure OVP/SCP setting method LSP setting procedure Timer latch function 3.2 Selection of DCDC components OCP setting procedure/DCDC component current tolerance selection procedure Selection of Inductor L Selection of switching MOSFET transistors Selection of rectifier diodes P28P30 P28,P29 P30 P30 P30 3.3 Timing chart P31 3.4 List of protection function P32 4. Caution on use P33 5. Ordering Information P34 6. Revision history P35 www.rohm.com (c) 2013 ROHM Co., Ltd. All rights reserved. TSZ2211115001 3/35 TSZ02201-0F10C1002000-1-2 19.Oct.2013 Rev.003 BD9470AFMBD9470AEFV Electrical Characteristics (unless otherwise specified, Ta = 25C, VCC=24V ) Parameter Symbol Specification Min Typ Max unit Condition Whole Device Operation Circuit Icc 5.5 8.5 mA STB=3V, PWM1-6=3.3V Standby current IST 40 80 A STB=0V Operating voltage (VCC VUVLO_VCC 6.5 7.5 8.5 V VCC=SWEEP UP Hysteresis voltage VCC VUHYS_VCC 150 300 600 mV VCC=SWEEP DOWN UVLO release voltage VUVLO_U 2.88 3.00 3.12 V VUVLO=SWEEP UP UVLO hysteresis voltage VUHYS_U 250 300 350 mV VUVLO=SWEEP DOWN UVLO pin leakage current UVLO_LK -2 0 2 A VUVLO=4V VLED 0.36 0.40 0.44 V VLED 0.428 0.450 0.472 V FCT 142.5 150 157. 5 KHz RT=100kohm NMAX_DUTY 90 95 99 % RT=100kohm RT short protection range RT_DET -0.3 - VRTx90% V RT=SWEEP DOWN On resistance on N pin source side RONSO 1.5 3 6 On resistance on N pin sink side RONSI 1.5 3 6 VRT 1 1.5 2 V RT=100kohm ISSSO -2.6 -2.0 -1.4 A VSS=2V VSS_END 3.52 3.70 3.88 V SS=SWEEP UP FB source current IFBSO -115 -100 -85 A VLED=0V, VFB=1.0V FB sink current IFBSI 70 100 130 A VLED=5.0V(ALL_CH), VFB=1.0V,VSS=4V FB_SO_SS 4.9 - - V SS=SWEEP UP FB_SOSI_SS 3.9 - 4.4 V SS=SWEEP DOWN Over current detect voltage VCS 372 400 428 mV CS=SWEEP UP CS source current ICS 15 30 60 A VCS=0V VOVP 2.90 3.00 3.10 V VOVP SWEEP UP V VOVP SWEEP DOWN UVLO Block DC/DC Block Error amp. Reference voltage (Min) Error amp. basic voltage (ILED=130mA) Oscillation frequency Max. duty cycle of output N RT pin voltage SS pin source current Soft start completion voltage FB source mode SS pin input voltage range FB sink/source mode SS pin input voltage range LEDx Terminal 40mA LEDx Terminal 130mA ILEDx = ILEDx = DC/DC protection Block OVP Detect Stop) Voltage (DCDC OVP protection timer release Short protection detect voltage OVP pin leakage current www.rohm.com (c) 2013 ROHM Co., Ltd. All rights reserved. TSZ2211115001 VOVP_CAN VOVP-0.14 VOVP-0.1 VOVP-0.04 VSCP 0.05 0.1 0.15 V VOVP SWEEP DOWN OVP_LK -2 0 2 A VOVP=4V 4/35 TSZ02201-0F10C1002000-1-2 19.Oct.2013 Rev.003 BD9470AFMBD9470AEFV Electrical Characteristics (unless otherwise specified, Ta = 25C, VCC=24V) Parameter Symbol Specification Min Typ Max unit Condition LED Driver Block LED pin current accuracy1 ILED1 -2 - 2 % ILED=130mA LED pin current accuracy2 ILED2 -2.5 - 2.5 % ILED=150mA LED pin leakage current ILED3 -3.5 3.5 % ILED=250mA ISET pin voltage ILLED -0.8 - 0.8 uA STB=H, LEDx=40V LED pin current accuracy1 VISET 1.3 1.5 1.7 V RISET=30k ISET_DET -0.3 - VISETx90% V ISET=SWEEP DOWN PWMx=L, LED protection Block ISET short circuit protection range VLSP 8.5 9 9.5 V LEDx=SWEEPUP, LSP=OPEN LSP pin resistive divider(Higher R) RULSP 1860 3100 5580 k LSP=0V LSP pin resistive divider(Lower R) RDLSP 540 900 1620 k LSP=4V LED OPEN detect voltage VOPEN 0.15 0.20 0.25 V LEDx=SWEEP DOWN REG58 output voltage 1 REG58_1 5.742 5.8 5.858 V IO=0mA REG58 output voltage 2 REG58_2 5.713 5.8 5.887 V IO=-15mA REG58 max output current | IREG58 | 15 - mA REG58_UVLOdetect voltage REG58_TH 2.1 2.4 2.7 V REG58_UVLO Hysteresis REG58_HYS 100 200 400 mV REG58 Discharge current REG58_DIS 3.0 5.0 7.0 uA STB=ON->OFF REG58=4V STB pin HIGH voltage STBH 2 - 35 V STB=SWEEP UP STB pin LOW voltage STBL -0.3 - 0.8 V STB=SWEEP DOWN STB pin Pull Down resistance RSTB 600 1000 1800 k VSTB=3.0V PWM pin HIGH voltage PWM_H 1.5 - 15 V PWM=SWEEP UP PWM pin LOW voltage PWM_L -0.3 - 0.8 V PWM=SWEEP DOWN PWM pin Pull Down resistance RPWM 1200 2000 3600 k PWM=3.0V FAIL Pin Ron RFAIL 250 500 1000 VFAIL=1.0V FAIL Pin Leakage current ILFAIL -2 0 2 A VFAIL=5V LEDSHORT protection voltage REG58 BLock STB=ON REG58=SWEEP DOWN STB=ON->OFF REG58=SWEEP DOWN STB Block PWM Block FAIL BlockOPEN DRAIN www.rohm.com (c) 2013 ROHM Co., Ltd. All rights reserved. TSZ2211115001 5/35 TSZ02201-0F10C1002000-1-2 19.Oct.2013 Rev.003 BD9470AFMBD9470AEFV Pin Numbers/Names/Functions Pin No. Pin Name HSOP-M28 HTSSOP-B28 Symbol Function 1 8 ISET 2 9 PWM1 PWM light modulation signal input pin for LED1 3 10 PWM2 PWM light modulation signal input pin for LED2 4 11 PWM3 PWM light modulation signal input pin for LED3 5 12 PWM4 PWM light modulation signal input pin for LED4 6 13 PWM5 PWM light modulation signal input pin for LED5 7 14 PWM6 PWM light modulation signal input pin for LED6 8 15 GND Ground pin for analog block 9 16 FAIL Error detection output pin 10 17 OVP Overvoltage protection detection pin 11 18 LED6 LED output 6 12 19 LED5 LED output 5 13 20 LED4 LED output 4 14 21 LED_GND 15 22 LED3 LED output 3 16 23 LED2 LED output 2 17 24 LED1 LED output 1 18 25 UVLO Detection pin for Under voltage Lockout prevention 19 26 LSP LED short-circuit protection voltage setting pin 20 27 STB Enable pin 21 28 VCC Power supply pin 22 1 REG58 23 2 CS 24 3 N 25 4 DCDC_GND 26 5 RT DCDC Drive frequency setting connection pin 27 6 FB Error Amp output pin 28 7 SS Slow start/ LED protection masking time setting pin LED current setting resistor connection pin Ground pin for LED 5.8V regulator output pin / Shutdown timer pin DC/DC output current detection pin OCP detection pin DC/DC switching output pin DC/DC GND pin External Component Recommended Range Parameter Symbol Specification VCC pin connecting capacity CVCC 0.1 100 F VCC pin connecting resistance RVCC 0 *1 k REG58 pin connecting capacity C_REG 1.0470 F CSS 0.0011.0 F RRT 30150 k RISET 12.1675 k Soft start setting capacity RT pin connection resistance range ISET pin connecting resistance range unit The operating conditions listed above are constants for the IC alone. To make constant setting with practical set devices, utmost attention should be paid. *1 Please refer to 3.2 function explanatiob and selection of external components for thes election of VCC series resistance. www.rohm.com (c) 2013 ROHM Co., Ltd. All rights reserved. TSZ2211115001 6/35 TSZ02201-0F10C1002000-1-2 19.Oct.2013 Rev.003 BD9470AFMBD9470AEFV Internal Equivalent Circuit Diagrams REG58 / N / CS / DCDC_GND SS FB SS REG58 N FB DCDC_GND CS OVP ISET RT 2k OVP 4k 100k STB FAIL STB 1M 5V RT ISET 5V UVLO FAIL 1M 500 1M LED1-6/LED_GND UVLO 5V PWM LSP LED1-6 4V PWM1-6 100k 3.1M LSP 100k 5V 2M 5V 900k LED_GND Figure 6. Internal Equivalent Circuit Diagrams www.rohm.com (c) 2013 ROHM Co., Ltd. All rights reserved. TSZ2211115001 7/35 TSZ02201-0F10C1002000-1-2 19.Oct.2013 Rev.003 BD9470AFMBD9470AEFV Block Diagram VIN C IN + CREG COUT REG58 OS DET VCC VCC C VCC UVLO UVLO (VCC) STB TSD UVLO SCP OVP OVP Timer LOGIC VREG FAIL PWM COMP + + + RT OSC Driver Control Logic Current Sence REG58 N CS SS SS Css AGND Rpc - Cpc + Use at At sink source mode SS FB Clamp FB ERR AMP SS_END DCDC_GND LED1 LED2 LED3 LED4 LED5 LED6 Current driver PWM1 PWM2 PWM3 PWM4 PWM5 PWM6 3V 1.5V LEDGND ISET ISET SS_END 4V Open-Short Detect 0.9V LSP OSDET Figure 7. Block Diagram Characteristic date(reference date) 10 7.0 9 6.5 REG58[V] ICC[mA] 8 7 6 5 6.0 5.5 4 5.0 3 9 14 19 24 VCC[V] 29 34 Figure 8. ICC[mA] vs VCC[V] www.rohm.com (c) 2013 ROHM Co., Ltd. All rights reserved. TSZ2211115001 9 14 19 24 VCC[V] 29 34 Figure 9. REG58[V] vs VCC[V] 8/35 TSZ02201-0F10C1002000-1-2 19.Oct.2013 Rev.003 BD9470AFMBD9470AEFV 140 160 138 120 136 80 40 132 IFB[uA] ILED[mA] 134 130 128 0 -40 126 -80 124 -120 122 80 LEDx[V] Figure 11. IFB[uA] vs LEDx[V] ( @ILED=130mA) Figure 10. ILED[mA] vs Temp[] 1000 1000 FCT [ kHz ] ILEDx[mA] 1.0 60 0.8 20 40 Temp[] 0.6 0 0.4 -20 0.0 -40 0.2 -160 120 100 10 100 10 10 100 RISET[kohm] 100 RRT[kohm] 1000 Figure 13. FCT [kHz] vs RRT[kohm] Figure 12. ILEDx[mA] vs RISET[kohm] www.rohm.com (c) 2013 ROHM Co., Ltd. All rights reserved. TSZ2211115001 10 9/35 TSZ02201-0F10C1002000-1-2 19.Oct.2013 Rev.003 BD9470AFMBD9470AEFV 2. Understanding BD9470AEFVBD9470AFM Pin Functions ISET HTSSOP-B28:8PIN/HSOP-M281PIN The ISET pin is a resister value of output current setting. The output current ILED vary in inverse proportion to resister value. The relation of the output current ILED and ISET pin connecting resistor RISET are as bellow. RISET = 3000 [k] I LED [mA] However, current setting range is from 40mA to 150mA. And the setting of ISET resistor is bellow at using 150mA to 250mA. RISET = 2653 x ( I LED [mA] ) -0.9753 [k] ILED(mA) 150 160 170 180 190 200 210 220 230 240 250 RSET(kohm) 20.00 18.80 17.72 16.76 15.90 15.12 14.42 13.78 13.19 12.66 12.16 For a setting example, please refer to `3.1 application explanation / LED current setting'. When the RISET is shorted and the ISET pin is grand shorted, the LED current is OFF and the FAIL=OPEN(abnormal signal) to prevent flowing a large current to LED pin when it becomes less than VISETx0.90V(typ). When the ISET pin back to normal state the LED current return to former system, too and the FAIL=GND(normal signal). It prepare automatically to suitable LED feedback voltage that can output LED current set by ISET pin. In short LED feedback voltage is dropped when the LED current is small and the IC heating is held automatically. In case of a large current is needed, raise the LED pin feedback voltage. And it adjust automatically to LED pin voltage that can be flow large LED current. The calculation is as below. VLED = 3.462 x I LED [ A] [V ] The LED feedback voltage (VLED) is clamped to 0.4V(typ.) when the LED current (ILED) is less than 115.6mA. PWM1-6 HTSSOP-B28:9,10,11,12,13,14PIN / HSOP-M282,3,4,5,6,7PIN The ON/OFF pin for LED driver. Light can be modulated by changing the duty cycle through the direct input of a PWM light modulation signal in each PWM pin. The high and low voltage levels of PWM_x pins are as listed in the table below. State PWMxvoltage LED ON state PWMx=1.5V~15.0V PWMx=0.3V0.8V LED OFF state The sequence of STB/PWM for start-up, please input PWM signal before STB or the same timing STB=PWM=ON. GND HTSSOP-B28:15PIN / IC internal analog GND pin. HSOP-M288PIN FAIL HTSSOP-B28:16PIN / HSOP-M289PIN FAIL signal output pin OPEN DRAIN.Internal NMOS will become OPEN while abnormal is detected. State FAILoutput Normal GND AbnormalAfter Timer Latch OPEN Level OVP HTSSOP-B28:17PIN / HSOP-M2810PIN The OVP pin is an input pin for overvoltage protection and short circuit protection of DC/DC output voltage. If over voltage is detected, the OVP pin will stop the DC/DC converter conducting step-up operation. If Vout was increased by abnormality, timer is set while OVP2.9V(typ.).when it comes to OVP3.0V, timer will ON at the same time and to stop DCDC. Although Counter will be stopped when OVP2.9V during counting time, in the state of OVP>2.9V, when internal counter 18 completed 2 count 262152 count, the system will be latched. When the short circuit protection (SCP) function is activated, the DC/DC converter will stop operation, and then the timer 16 will start counting, after 2 count65536 count, DCDC and LED driver will stop and latch. The OVP pin is of the high impedance type and involves no pull-down resistor, resulting in unstable potential in the open-circuit state. To avoid this problem, be sure to make input voltage setting with the use of a resistive divider or otherwise. OVP pin will be feedback pin when PWM=L. Also, this pin will hold OVP voltage at that time when switch PWM = H to L. For setting example, refer to information in"3.4 Selection of External Components-OVP/SCP setting procedure OVP Voltage keep internal IC with PWM=Low timing, and VOUT voltage can hold by using copied OVP voltage while PWM=Low.The OVP keep voltage range is 0~3V, 30steps.For setting example, refer to information in "3.2 Selection of External Components", "Explanation of VOUTOVP voltage holding function when PWM=Low" www.rohm.com (c) 2013 ROHM Co., Ltd. All rights reserved. TSZ2211115001 10/35 TSZ02201-0F10C1002000-1-2 19.Oct.2013 Rev.003 BD9470AFMBD9470AEFV LED1-6 HTSSOP-B28:18,19,20,22,23,24PIN / HSOP-M2811,12,13,15,16,17PIN LED constant current output pins. Current value setting can be made by connecting a resistor to the ISET pin. For the current value setting procedure, refer to the description of "ISET pin". If any of the LED pins is put in an abnormality state (short circuit mode, open circuit mode, ground short mode), the relevant protection function will be activated. LED pin short circuit protection function ( LSP) When any LED is in short state (more than LED=9.0V(typ)) the LED SHORT is detected. 16 After abnormal detection, the timer count starts. The LED that is abnormal detection after 2 count is stopped and other LED driver operates normally. LED pin open circuit protection function (LOP) If any of the LED pins becomes open-circuited (0.2V (Typ.) or less), LED_OPEN will be detected. When this error is detected, the timer will start counting, When it completes counting the preset period of time, only LED driver that detected the error will stop operation and other LED driver will conduct normal operation. LED GND_SHORT protection function When any LED pin is GND shorted the LED pin becomes less than 0.20V and the pin is latched because of LED_OPEN detection. After that, the LED pin is pull upped by inner supply but it continues less than 0.2V state in grand shorted. After 7 detecting timer of open state, if the grand shorted (open) state continues 2 counts all systems are latched. To prevent the miss detection there is 4 count interval of mask before starting the timer count. If PWM=H time is PWM=H time < 4countNot detect protection because it is in interval time PWM=H time > 4countDetect protection because it is out of interval time Please verify enough to operate narrow PWM. 9V LEDx Interval of mask Timer count CLK 1 2 3 4 1 2 216 FAIL Figure 14. Timing chart of timer count LED_GND HTSSOP-B28:21PIN / HSOP-M2814PIN The LED_GND pin is a power ground pin used for the LED driver block. UVLO HTSSOP-B28:25PIN / HSOP-M2818PIN This pin is used to for step-up DC/DC converter. When UVLO pin voltage reaches 3.0V (Typ.) or more, IC will initiate step-up operation. If it reaches 2.7V (Typ.) or less, the IC will stop the step-up operation. The UVLO pin is of the high impedance type and involves no pull-down resistor, resulting in unstable potential in the open-circuited state. To avoid this problem, be sure to make input voltage setting with the use of a resistive divider or otherwise. For calculation examples, refer to information in '3.1 application explanation/UVLO setting procedure' LSP HTSSOP-B28:26PIN / HSOP-M2819PIN The setting pin for detection voltage of LED short circuit protection. The LED short circuit detection voltage is set to 9V (Typ.) with the LSP pin being in the open-circuited state. However, making a change to the LSP pin input voltage will allow the threshold for LED short circuit protection to be changed. The relation between the LSP pin voltage and the LED short circuit protection detection voltage is given by the following equation. VLSPSHORT = VLEDSHORT [V ] 10 Here LEDSHORTLED detection voltage VLSPLSP setting voltage LSP pin input voltage setting should be made in the range of 0.3V to 2.5V. For setting example, refer to information in'3.1 application explanation/LSP setting procedure' www.rohm.com (c) 2013 ROHM Co., Ltd. All rights reserved. TSZ2211115001 11/35 TSZ02201-0F10C1002000-1-2 19.Oct.2013 Rev.003 BD9470AFMBD9470AEFV STB (HTSSOP-B28:27PIN / HSOP-M2820PIN The pin is used to ON/OFF the IC and allowed for use to reset the IC from shutdown. The IC state is switched between ON and OFF state according to voltages input in the STB pin. Avoid using the STB pin between two states (0.8 to 2.0V). Input sequence of STB/PWM for startup, please input PWM before STB or at the same timing. While in shutdown mode, the timer keeps counting until the IC is completely shut down. For details of shutdown operation, refer to information in'3.1 application explanation/ the setting of REG58 capacity and shutdown procedure' VCC HTSSOP-B28:28PIN / HSOP-M2821PIN IC power supply pin. Input range is 9~35V. VCC pin voltage reaches 7.5V (Typ.) or more, the IC will initiate operation. If it reaches 7.2V (Typ.) or less, IC will be shut down. REG58 HTSSOP-B28:1PIN / HSOP-M2822PIN The REG pin is used in the DC/DC converter driver block to output 5.8V voltage. The maximum operating current is 15mA.Using the REG pin at a current higher than 15mA can affect the N pin output pulse, causing the IC to malfunction and leading to heat generation of the IC itself. To avoid this problem, it is recommended to make load setting to the minimum level. In addition, The REG58 pin is also allowed for use as discharge timer for DC/DC output capacitance. For details, refer to information in '3.1 application explanation/ the setting of REG58 capacity and shutdown procedure' CS HTSSOP-B28:2PIN / HSOP-M2823PIN The CS pin has the following two functions. DC/DC current mode current feed Back function Current flowing through the inductor is converted into voltage by the current sensing resistor RCS which connected to CS pin and this voltage is compared with voltage set with the error amplifier to control the DC/DC output voltage. 2Inductor current limit function (OCP pin) The CS pin also incorporates the overcurrent protection (OCP) function. If the CS pin voltage reaches 0.4V (Typ.) or more, switching operation will be forcedly stopped. For detailed explanation, Please refer to information in "3.2 Selection of DC/DC Components-OCP setting procedure / DC/DC component current tolerance selection procedure". N HTSSOP-B28:3PIN / HSOP-M2824PIN The N pin is used to output power to the external NMOS gate driver for the DC/DC converter in the amplitude range of approximately 0 to 5.8V.Frequency setting can be adjusted by a resistor connected to the RT pin. For details of frequency setting, refer to the description of the RT pin. DCDC_GND HTSSOP-B28:4PIN / HSOP-M2825PIN The DCDC_GND pin is a power ground pin for the driver block of the output pin N. RT HTSSOP-B28:5PIN / HSOP-M2826PIN The RT pin is used to connect a DC/DC frequency setting resistor. DC/DC drive frequency is determined by connecting the RT resistor. Relationship between Drive frequency and RT resistance (Ideal) RRT = 15000 f SW [kHz ] [k] However, drive frequency setting is limited in the range of 100 kHz to 500kHz. For calculation, refer to information in '3.1 application explanation/ DC/DC converter drive frequency setting' When it reaches under VRTx0.90V(typ), DCDC operation will be stopped in order to prevent from high speed oscillation when the RT resistance is shorted to GND. And when RT pin returns to normal state, DCDC also returns to operation. FB HTSSOP-B28:6PIN / HSOP-M2827PIN The FB pin is an output of DC/DC current mode error amplifier. FB pin detects the voltages of LED pins (1 to 6) and controls inductor current so that the pin voltage of the LED located in the row with the highest Vf will come to 0.45V(130mA, typ.). Therefore, the pin voltages of other LEDs will become higher by Vf variation. FB Voltage keep internal IC with PWM=Low timing, and it can hold by using copied FB voltage while PWM=Low.The FB keep voltage range is 0~4V, 40steps For setting example, refer to information in '3.1 application explanation/ the necessity for holding output voltage and FB voltage while PWM=Low' SS HTSSOP-B28:7PIN / HSOP-M2828PIN Soft start time and duty for soft start setting pin. The SS pin normally sources 2.0uA (Typ.) of current. The IC has a built-in soft start start-up circuit independent of PWM light modulation, and thereby raises FB voltage as SS pin voltage rises independent of the duty cycle range of PWM light modulation. When the SS pin voltage reaches 3.7V (Typ.), soft start operation will be completed to unmask the LED protection function. For setting example, refer to information in '3.1 application explanation/ start-up and SS capacity setting explanation' www.rohm.com (c) 2013 ROHM Co., Ltd. All rights reserved. TSZ2211115001 12/35 TSZ02201-0F10C1002000-1-2 19.Oct.2013 Rev.003 BD9470AFMBD9470AEFV 3. Application of BD9470AEFVBD9470AFM 3.1 BD9470AEFVBD9470AFM examination for application Start-up and SS capacity setting explanation This section described the start-up sequence of this IC. STB 2uA 5V SS SLOPE FB PWM SS OSC VOUT Q D COMP N Css DRIVER PWM OSC SS=FB Circuit ILED SS SLOPE LED 0.3 0.519V VOUT ILED LED_OK OVP KEEP OVP PWM LED_OK PWM=L:STOP FB STOP/ACT LED_OK N LED_DRIVER Figure 15. Timing chart of start-up Description of start-up sequence STB=PWM=ON System is ON.SS starts to charge. At this time, a circuit in which SS voltage for slow start is equal to FB voltage regardless of whether the PWM pin is set to Low or High level. Since the FB pin and SS pin reach the lower limit of the internal sawtooth wave, the DC/DC converter operates and VOUT voltage rising. Until it reachs a certain voltage even PWM=Low by vlotage maintenance function. For detailed OVP maintanence function, please refer to"VOUT(OVP) maintanence function section". Vout voltage continues rising to reach a voltage at which LED current starts flowing. When the LED current reaches the set amount of current, isolate the FB circuit from the SS circuit. With this, the start-up operation is completed.Fast start-up is also diasabled by VOUT maintanence function After that, conduct normal operation following the feedback operation sequence with the LED pins. If the SS pin voltage reaches 3.7V or more, the LED protection function will be activated to forcedly end the SS and FBequalizing circuit. VSS>4.9V FB=Source Mode REG58 4.9V V Vss Iss[A] V SS Vss, VFB[V] VREG58[V] SS capacity setting method 4.7VVss FB Output Current =Source Only Finished Start Up SS=FB Css[F] Time Figure 16. SS setting procedure in FB Source mode Boot system as above described, because of start-up in the state of FB=SS, the start-up time can be imaged of the time to reach the point from the feedback voltage FB from STB = ON.If you SS> 4.9V, FB output current mode will become Source mode operation. If the feedback voltage of FB is the same as VSS and the time can be calculated as below. Tss = www.rohm.com (c) 2013 ROHM Co., Ltd. All rights reserved. TSZ2211115001 C ss [ F ] x VFB[V ] 2[ A] [ Sec] 13/35 TSZ02201-0F10C1002000-1-2 19.Oct.2013 Rev.003 BD9470AFMBD9470AEFV However, if SS is set too short, inductor rush current will occur during start-up.In addition, if SS time is set too long, will result in the brighter in stages.SS capacity will veries with various factors, such as voltagestep-up ratio, DCDC driver frequency, LED current and output output condencer, so it is recommended to test and confirm on the actual system. SS capacity is often set at about 0.047uF0.47uF approximately as a reference value Setting example SS time when the start-up is complete and Css = 0.1uF, Iss = 2uA, Vss = 3.7V will be calculated as follows. Tss = 0.1 E -6 [F] x 3.7 [ V ] = 0.185 2 E -6 [ A ] [Sec ] In addition, when FB output is operated in Sink/Source moderefer to "FB pin output current setting for detailed explanation., SS voltage can be set to be in the range of 3.9V4.4V at the SS pin voltage resistor divider.Soft-start time will be set in that case is as follows. A x Vss[V ] 1 ln1 - A B A= [Sec ] R1 [ohm ] + R 2 [ohm ] Css [F ] x R1 [ohm ] x R 2 [ohm ] VREG58 [V ] + Iss[ A] / Css[F ] B = 1 [ ] R ohm 3.9V<VSS<4.4V FB=Sin/Source Mode REG58 R1[ohm] 4.9V Iss[A] V SS 3.9VVss4.4V FB Output Current =Sink & Source mode Css[F] Vss, VFB[V] 4.4V Vss V R2[ohm] VREG58[V] Tss = - 3.9V Finished Start Up SS=FB Time Figure 17. SS setting procedure in FB sink/ source mode Setting example When R1=200kohm, R2=470kohm, Css=1.0uF, VREG58=5.8V, Iss=2uA, Vss=3.7V, SS time is set as below Tss = - 1 7.12 x 3.7 ln1 - = 0.266 [Sec ] 7.12 31 www.rohm.com (c) 2013 ROHM Co., Ltd. All rights reserved. TSZ2211115001 14/35 TSZ02201-0F10C1002000-1-2 19.Oct.2013 Rev.003 BD9470AFMBD9470AEFV The setting of REG58 capacity and shutdown procedure VOUT discharge function is built-in this IC when IC is shutdowned, the below decribes the operation sequence. STB VOUT REG50 2.4V STB 1uS Pulse ALL SHUTDOWN ON->OFF N DRIVER PWM REG58 CS 5uA CREG N 2.4V/2.5V ILED REG58 LED ALL SHUTDOWN PWM VOUT PWM=L:STOP LED_DRIVER ILED Figure 18.Timing chart of shutdown Explanation of shutdown sequence Set STB pin to "OFF" will stops DC/DC converter and REG58, but LED driver will remain operation. Reset signal is output 1uS extent to reset the latch on the IC at this time.Therefore, undershooting will be generated on LED current, but 1uS is very short will not affect The brightness. Discharge the REG58 pin voltage from 5.8V to 2.4V with -5uA current. The VOUT voltage will be fully discharged with ILED current and the ILED current will no longer flow. When REG58pin voltage will reach 2.4V (Typ.) or less to shut down all systems REG58 capacitance setting procedure The shutdown time "TOFF" can be calaulated by the following equation. TOFF = CREG [F ] x 3.4 [V ] 5 [uA] [Sec ] The longest VOUT discharge time will be obtained when the PWM duty cycle is set to the minimum VOUT. Make REG capacitance setting with an adequate margin so that systems will be shut off after VOUT voltage is fully discharged. www.rohm.com (c) 2013 ROHM Co., Ltd. All rights reserved. TSZ2211115001 15/35 TSZ02201-0F10C1002000-1-2 19.Oct.2013 Rev.003 BD9470AFMBD9470AEFV VCC series resistance setting procedure By inserting a series resistor to VCC will has the following affection. Reduce the voltage VCC, and it is possible to suppress the heat generation of IC. ICCxVIN is power consumption of IC Possible to Raise the surge ability to VCC. However, if resistance is set too large, it is needed to consider that will result in VCC become VCC<9V Minimum operation voltage.So the appropriate series resistance setting is needed. VIN RVCC V VCC I_IN ICC The current influx of IC I_IN as shown on the right is Circuit current of IC...ICC Current to load is connected toREG58...IREG Current which used to drive DCDC FET...IDCDC There are 3 paths within IC and the V of RVCC can be decided. VCC voltage generated by the relation as above described at that time can be represented as below. + - RREG IDCDC VCC[V ] = VIN [V ] - (ICC[ A] + IDCDC[ A] + IREG[ A] ) x RVCC[] [ V ] > 9[V ] The Criterion of 9V is the minimum operating limit of the IC. When a series resistance is considered, please set with a sufficient margin. IREG REG58 IC BLOCK DCDC DRIVER N I_N Figure 19. ICC paths diagram Setting example Above equation can be transformed as below. RVCC[] < VIN [V ] - 9[V ] ICC[ A] + IDCDC[ A] + IREG[ A] In typical operation, VIN=24V, ICC=5.5mA, RREG=10k, IDCDC=2mA can be assumed and the VCC voltage is RVCC[] < 24[V ] - 9[V ] = 1.86[k] 0.0055[ A] + 0.002[ A] + 5.8[V ] 10000[] However, the result is in typical operation and the variability and margin is not considered. If the variability of VIN=24Vx(-20%,ICC=8.5A,RREG=10kx(-5%,REG58=5.8Vx(+5%),IDCDC=2mAx(+100%),VCC operation limit voltage9Vx(+20%) are assumed: RVCC[] < 24 x 0.8[V ] - 9 x 1.2[V ] = 640[] 0.0085[ A] + 0.002 x 2[ A] + 5.8 x 1.015[V ] (10000[] x 0.95) According to above result, set RVCC = 640 or less is adequate on actual application. When a series resistance is considered, please set with a sufficient margin. www.rohm.com (c) 2013 ROHM Co., Ltd. All rights reserved. TSZ2211115001 16/35 TSZ02201-0F10C1002000-1-2 19.Oct.2013 Rev.003 BD9470AFMBD9470AEFV The necessity for holding output voltage and FB voltage while PWM=Low In conventional control method, DCDC will be stopped and FB voltage become high impendence while PWM=Low. However, if PWM=0% is continued to inputted to system, output voltage and FB voltage is reduced because of discharge phenomenon.eventually output voltage is equal to VIN, and FB voltage drop to 0V.There are several problems such as the following listed if PWM dimming signal is tried to light-up a system. Slow start cannot be controlled resulting in the FB voltage overshoot and rush current flow to Inductor. Flash phenomenon occur due to start-up control does not work. Because there is a need to re-boost, take a long time to light up. In this IC, the problems as above mentioned is resolved by coping output voltage and FB voltage to IC internally at a time of PWM from High to Low. The below describes FB and VOUT voltage holding function in detail. Explanation of FB voltage holding function while PWM=Low PWM signal H L - L - H L FB GMAMP - LED1 LED2 H 100pF2200pF H + L FB IN FB COPY Holding FB Vol. BLOCK Figure 20. Block diagram of KEEP_FB FB holding function means FB voltage will be copy to IC internally at a time of PWM from High to Low, FB voltage will be maintained even in the period of PWM=Low. Because FB voltage resolution is split by 40 from 4V, so the voltage can be copied to IC internally in 0.1V Step. In addition, FB pin voltage will be influenced by DCDC operation, the copied have 0.1V difference problem. But because FB voltage is returned as feedback voltage immediately and will not cause an operational problem while PWM=H, it is recommended to add about 100pF2200pF to FB pin for noise reduction. www.rohm.com (c) 2013 ROHM Co., Ltd. All rights reserved. TSZ2211115001 17/35 TSZ02201-0F10C1002000-1-2 19.Oct.2013 Rev.003 BD9470AFMBD9470AEFV PWM FB FB COPY Figure 21. Timing chart of KEEP_FB PWM=High, normal feedback operation by LED pin FB voltage is copied to IC at a time of PWM from High to Low. FB voltage will be copied by less than 1Bit. For Examplewhen FB=2.16V, FB COPY voltage is 2.1V. GMAMP is works as Buffer with while PWM=Low, FB voltage is discharged to FB COPY voltage. FB COPY=FB voltage. FB COPY=FB voltage and maintain. If PWM=0% and because follow the state continuously, FB voltage will not dropped by natural discharge. Notice FB voltage holding function is performed at 0.1V STEP. If PWM signal is in low duty, FB voltage is not able to rise sufficiently when FB series resistance is small causing to RFBxIFB(typ.100uA)0.1V(typ.), The output voltage may not be boosted up to the set voltage. Therefore, it is recommended to set RFB> 2kohm so that V = RFB x IFB> 0.2V. IFB(100uA typ) FB RFB V=RFBxIFB>0.2V CFB Figure 22. Voltage to FB resistor www.rohm.com (c) 2013 ROHM Co., Ltd. All rights reserved. TSZ2211115001 18/35 TSZ02201-0F10C1002000-1-2 19.Oct.2013 Rev.003 BD9470AFMBD9470AEFV Explanation of VOUTOVP voltage holding function when PWM=Low VIN VOUT VCC OVP OVP_IN OVP COPY LED_OK Holding OVP Vol. BLOCK PWM signal - H : DCDC ON L : DCDC OFF OVP COMP + FB SLOPE + + - SS + ICOMP CONTROL LOGIC DRIVER N CS DCDC_GND LED1-6 Figure 23. Block diagram of KEEP_OVP OVP holding function means VOUT(OVP) voltage will be copy to IC internally at a time of PWM from High to Low, voltage will be maintained even in the period of PWM=Low. In addition to measures of the above problems, by applying this function, the high-speed start-up can be achieved without depending on the PWM. Because VOUT voltage resolution is the same as FB holding function which is split by 40 from 4V,so the voltage can be copied to IC internally in 0.1V Step. The description of OVP holding function is divided into narrow PWM operation and start-up operation. Explanation of OVP holding function at start-up PWM OVP OVP COPY N Figure 24. Timing chart 1 of KEEP_OVP In order to launch high speed start-up without depending on the PWM DUTY, OVP holding function will behave like the following descriptions. PWM=High, normal boost operation. OVP voltage is copied into IC when PWM is from High to Low.OVP voltage will be copied upper 1BIT at this time. For example: if OVP=2.43V, the copied voltage is 2.5V in IC. The copied OVP voltage will be compared with OVP pin voltage internally, if OVP_COPY>OVP, DCDC is operated.In other words, it is possible to achieve fast start-up by letting the voltage on the 1BIT boosted up in the interval of PWM = Low. When OVP_COPY<OVP pin voltage, DCDC is stopped. Even if in the period of PWM=Low and VOUT is discharged, output voltage will be hold by performing DCDC operation in order to let OVP_COPYOVP pin voltage. www.rohm.com (c) 2013 ROHM Co., Ltd. All rights reserved. TSZ2211115001 19/35 TSZ02201-0F10C1002000-1-2 19.Oct.2013 Rev.003 BD9470AFMBD9470AEFV Explanation of OVP holding function in narrow PWM duty PWM OVP OVP COPY N Figure 25. Timing chart 2 of KEEP_OVP DCDC operates only in the duration of PWM=High while narrow PWM is inputted, output voltage drops when PWM=0%. But, DCDC is operated by coping voltage even if PWM=Low duration in this IC and output voltage will not drops. PWM=High, normal operation. OVP voltage is copied into IC when PWM is from High to Low.OVP voltage will be copied under 1BIT at this time. For example: if OVP=2.43V, the copied voltage is 2.4V in IC. VOUT is discharged by OVP resistance. When copied OVP_COPYOVP pin voltage, DCDC is operated, when OVP_COPYOVP voltage, DCDC is stops. When operates in PWM=0%, the point will be repeated and repeated, so the output voltage will not drops naturally. Condition of copy OVP voltage The copied OVP pin voltage as above explanation, it has upper and lower 1BIT difference according to below condition. Conditions of copy upper 1BIT From startup to completion of step-up OVP detection state Conditions of copy lower 1BIT Normal operation state ( OVP undetected state) The reason about why copy the voltage of upper 1BIT when OVP is detected When OVP is detected by OVP=3V and stops DCDC operation. After that while PWM=Low and if copy lower 1BIT voltage will results in OVP=2.9V and release OVP detection function, therefore it is designed to copy upper 1BIT when OVP is detected. www.rohm.com (c) 2013 ROHM Co., Ltd. All rights reserved. TSZ2211115001 20/35 TSZ02201-0F10C1002000-1-2 19.Oct.2013 Rev.003 BD9470AFMBD9470AEFV FB current Source modeSink/Source mode The output of GMAMP is constant current control in normal operation ans output anout100uA(typ.) in this IC. But, when PWM scanning operation and local dimming is performed, total LED current and output voltage will different by each timming and FB feedback voltage.The below describes the this operation. PWM 1,2,3 N PWM 4,5,6 CS CFB RCS RFB PGND FB PWM1 OVP PWM2 ILED FB PWM3 LED1 LED2 PWM4 LED3 LED4 LED5 LED6 PWM5 PWM6 VOUT Figure 26. Timing chart of FB sink/source mode As above shown,short PWM1,2,3 ans PWM4,5,6, assumed that scanning operation is performed. At this time, the sequence is described as below. When PWM4,5,6=HighLow, FB voltage, VOUTOVPvoltage is copied Copied voltage is hold. When PWM1,2,3=High again, normal DCDC operation When PWM4,5,6=High again, LED current increase. Because LED current increase resulting in FB voltage change.it take a long transition time because FB source current is 100uA at this time, therefore FB voltage is not insufficient and output voltage and LED current will drop. FB voltage reaches the feedback voltage and LED current and output voltage will operate normally. In other words, ILED current drops at the point , This may be due to the transition time of the behavior that FB current sink first and then charge again. www.rohm.com (c) 2013 ROHM Co., Ltd. All rights reserved. TSZ2211115001 21/35 TSZ02201-0F10C1002000-1-2 19.Oct.2013 Rev.003 BD9470AFMBD9470AEFV Therefore, in order to solve this problem in this IC, equipped with a mode of "FB current only source 0uA+100uA"as a countermeasure to reduce the LED current drop problem. "FB Source mode"is described as below. PWM 1,2,3 PWM 4,5,6 FB ILED VOUT Figure 27. Timing chart of FB source mode when PWM4,5,6=HighLow, FB voltage, VOUTOVPvoltage is copied copied voltage is hold. when PWM1,2,3=High again, normal DCDC operation.but, FB voltage is larger than feedback voltage, and VOUT setting voltage also higher. when PWM4,5,6=High, LED current increases. although LED current is increased but the FB voltage has reached the feedback voltage and will not change at this time.Therefore, there is no transition and VOUT, LED current will not drop. LED current and output voltage is operate normally When PWM1,2,3=Low, LED current reduces.But, FB is only has source ability , FB voltage is maintained continuely But, despite the decreasing of LED current, output voltage is increases because FB voltage is not changed. According to above operation, the LED undershoot problem cab be prevented by FB source mode. However, the above description is a simplified explanation for behavior, because the actual behavior of a waveform is different from the above, please check on the actual system. When FB source mode is used, care must be taken to the following contents. Because it can be held at a higher voltage than normal FB voltage, output voltage may be higher. Therefore, please note that the heat might be higher than PWM = 100% while scanning operation is performed. www.rohm.com (c) 2013 ROHM Co., Ltd. All rights reserved. TSZ2211115001 22/35 TSZ02201-0F10C1002000-1-2 19.Oct.2013 Rev.003 BD9470AFMBD9470AEFV LED Current setting Setting of LED output current "ILED" can be made by connecting a resistor RISET to the ISET pin. RISET and ILED current setting equation RISET = 3000 [k] I LED [mA] However, LED current setting should be made in the range of 40mA to 150mA. And the setting of ISET resistor is bellow at using 150mA to 250mA. RISET = 2653 x ( I LED [mA] ) -0.9753 [k] ILED(mA) 150 160 170 180 190 200 210 220 230 240 250 RSET(kohm) 20.00 18.80 17.72 16.76 15.90 15.12 14.42 13.78 13.19 12.66 12.16 Setting Example To set ILED current to 100mA, RISET resistance is given by the following equation RISET = 3000 3000 = = 30 [k] I LED [mA] 100[mA] DC/DC converter drive frequency setting DC/DC converter drive frequency is determined by making RT resistance setting. Drive frequency vs. RT resistance (ideal) equation RRT = 15000 f SW [kHz ] [k] Here fsw = DC/DC converter oscillation frequency [kHz] This equation has become an ideal equation without any correction item included. For accurate frequency settings, thorough verification should be performed on practical sets. Setting example To set DC/DC drive frequency "fsw" to 200 kHz, RRT is given by the following equation RRT = 15000 15000 = = 75 [k] f sw [kHz ] 200[kHz ] And , the drive frequency setting range is 100kHz500kHz. www.rohm.com (c) 2013 ROHM Co., Ltd. All rights reserved. TSZ2211115001 23/35 TSZ02201-0F10C1002000-1-2 19.Oct.2013 Rev.003 BD9470AFMBD9470AEFV UVLO setting procedure UVLO pin for step-up DC/DC power supply. If the UVLO pin voltage reaches 3.0V (Typ.) or more, the IC will start step-up operation. If it reaches 2.7V (Typ.) or less, the IC will stop the step-up operation. UVLO pin is the high impedance type and no pull-down resistor inside, resulting in unstable potential in the open-circuit state. To avoid this problem, be sure to set input voltage with the use of a resistive divider. While the VIN voltage to be detected is set by the use of resistive dividers R1 and R2 as described below, resistance setting will be made by the following equation. UVLO setting procedure Assume that VIN is reduced and detected, UVLO is "VINDET", R1 and R2 setting will be made by the following equation: R1 = R 2[k] x (VIN DET [V ] - 2.7[V ]) [k] 2.7[V ] UVLO release voltage setting equation When R1 and R2 setting is determined by the equation shown above, UVLO release voltage will be given by the following equation. VIN CAN = 3.0V x ( R1[k] + R 2[k]) [V ] R 2[k] VIN R1 ON/OFF UVLO + - R2 2.7V/3.0V CUVLO Figure 28. Block diagram of UVLO Setting example Assuming that the normal VIN operating voltage is 24V, UVLO detection voltage is 18V, and R2 resistance is 30k, R1 resistance setting is made by the following equation R1 = R 2[k] x (VIN DET [V ] - 2.7[V ]) (18[V ] - 2.7[V ]) = 30[k] x = 170 [k] 2.7[V ] 2.7[V ] And, when UVLO release voltage VINCAN setting is made with R1 and R2, it will be given by the following equation VIN CAN = 3.0[V ] x ( R1[k] + R 2[k]) 30[k] + 170[k] [V ] = 3.0[V ] x = 20 [V ] R 2[k] 30[k] To select DC/DC components, give consideration to IC variations as well as individual component variations, and then conduct thorough verification on actual systems. www.rohm.com (c) 2013 ROHM Co., Ltd. All rights reserved. TSZ2211115001 24/35 TSZ02201-0F10C1002000-1-2 19.Oct.2013 Rev.003 BD9470AFMBD9470AEFV OVP/SCP setting method The OVP pin is an input pin for overvoltage protection and short circuit protection of DC/DC output voltage. The OVP pin is a high impedance type and no pull-down resistor inside, resulting in unstable potential in the open circuit state. To avoid this problem, be sure to make input voltage setting with the use of a resistive divider. Conditions for each OVP protections are as listed in the table below. Protection name OVP Timer SET / OVP Cancel OVP Detect / DCDC STOP SCP Protection pin Detection Condition Release Condition Timer Operation Protection type FAIL pin OVP OVP>2.9V OVP<2.9V Yes All latch GND OVP OVP>3.0V OVP<3.0V No OVP OVP<0.1V OVP>0.1V Yes Only DCDC converter stops during detection All latch OPEN GND The following describes the setting procedures of that VOUT pin voltage to be detected is set by the use of resistive dividers R1 and R2 as shown in the circuit diagram below. OVP detection setting method Assuming that a voltage causing VOUT to abnormally rise and detecting OVP is "VOVPDET", R1 and R2 setting will be made by the following equation. R1 = R 2[k] x VOUT (VOVPDET [V ] - 3.0[V ]) [k] 3.0[V ] OVP R1 R2 Timer setOVP release setting equation DCDC_STOP_COMP When R1 and R2 setting is determined by the equation shown above, OVP release voltage VOVPCAN will be ( R1[k] + R 2[k]) [V ] R 2[k] N OVP_TIMER_COMP DRIVER + 2.9V SCP detection equation When R1 and R2 setting is determined by the equation shown above, SCP setting voltage VSCPDET will be given by the following equation. VSCPDET H:STOP L:ACT - given by the following equation: VOVPCAN = 2.9V x D Q + 3.0V ( R1[k] + R 2[k]) = 0.1V x [V ] R 2[k] - SCP_TIMER_COMP + 0.1V CP Timer 65536 CP Timer 65536x8 Figure 29. OVP block diagram Setting example Assuming that normal VOUT voltage is 40V, OVP detection voltage VOVPDET is 48V, and R2 resistance is 10k, R1 resistance is calculated by the following equation R1 = R 2[k] x (VOVPDET [V ] - 3.0[V ]) (48[V ] - 3[V ]) = 10[k] x = 150 [k] 3.0[V ] 3[V ] When OVP release voltage VOVPCAN setting is made with the said R1 and R2, it will be given by the following equation VOVPCAN = 2.9[V ] x ( R1[k] + R 2[k]) 10[k] + 150[k] [V ] = 2.9[V ] x = 46.4 [V ] R 2[k] 10[k] SCP detection voltage is given by the following equation VSCPDET = 0.1[V ] x ( R1[k] + R 2[k]) 10[k] + 150[k] = 0.1[V ] x = 1.6 [V ] [V ] R 2[k] 10[k] Give consideration to IC variations as well as individual component variations, and then evaluate on actual systems. www.rohm.com (c) 2013 ROHM Co., Ltd. All rights reserved. TSZ2211115001 25/35 TSZ02201-0F10C1002000-1-2 19.Oct.2013 Rev.003 BD9470AFMBD9470AEFV LSP setting procedure LED SHORT threshold voltage can be adjusted by setting LSP pin voltage. LED SHORT detection voltage is set to 9V when LSP pin=OPEN state. Please set input voltage of LSP pin from 0.3V~2.5V range. The relation between LSP pins and LED SHORT protection voltage as below. VLSPSHORT = VLEDSHORT [V ] 10 Also, LSP pin divides 4V within the IC using resistive dividers (see the circuit diagram shown below) Therefore, connecting an external resistor to the LSP pin will produce resistance combined with the internal IC resistance. Consequently, LSP pin voltage setting using external resistive dividers, it is recommended to connect them having resistance little affected by the internal resistance.(Smaller resistance have less influence on internal resistance, but will result in larger power consumption.) REG58=5.8V REF=4V + R3= 3100k R1 LSP R4 900k 900k CLSP R2 LEDx 100k Figure 30. LSP Block diagram LSP detection voltage setting If the setting of LSP detection voltage VLSP is made by dividing the REG58V voltage by the use of resistive dividers R1and R2, VLSP will be given by the following equation. R 2[k] x10 [V ] VLSP = REG58[V ] x (1) + R k R k ( 1 [ ] 2 [ ] However, this equation includes no internal IC resistance. If internal resistance is taken into account, detection voltage VLSP will be given by the following equation. R 2[k] x R 4[k] x (REG58[V ] x R3 + REF [V ] x R1[k]) x10 [V ] VLSP = (2) ( R1[k] x R3[k] x (R 2 + R 4) + R 2[k] x R 4[k] x (R1[k] + R3[k]) Make setting of R1 and R2 resistance so that a difference between resistance values found by Equations (1) and (2) will come to approximately 2% or less as a guide. Setting example Assuming that LSP is approximated by Equation (1) in order to set LSP detection voltage to 5V, R1 comes to 53k andR2 comes to 5k.LSP detection voltage taking into account internal IC resistance by Equation (2), it will be given as 5[k] x 900[k] x (5.8[V ] x 3100[k] + 4[V ] x 53[k]) x 10 = 5.033V [V ] VLSP = ( ) ( ) x x + + x x + ( 53 [ k ] 3100 [ k ] 5 [ k ] 900 [ k ] 5 [ k ] 900 [ k ] 53 [ k ] 3100 [ k ] The difference is given as: (5.033[V ] - 5[V ]) / 5[V ] x100 = 0.66% As a result, this setting will be little affected by internal impedance. www.rohm.com (c) 2013 ROHM Co., Ltd. All rights reserved. TSZ2211115001 26/35 TSZ02201-0F10C1002000-1-2 19.Oct.2013 Rev.003 BD9470AFMBD9470AEFV Timer latch function This IC has a built-in timer latch counter to make setting of timer latch time by counting a clock frequency set with the RT pin. Timer latch time The timer latch counter begins counting from the timing when any abnormal state is detected. The timer will be latched after a lapse of a period of time given by the following equation. If the abnormal state continues even when PWM is set to Low level, the counter will not reset counting. LATCH TIME = 216 x RRT R [k] = 65536 x RT 7 [ S ] 10 1.5 x 10 1.5 x 10 Here LATCHTIME= A period of time, which the timer is latched RRT=RT pin connecting resistance Protection time which described above is applied for LED pin OPEN protection, LED pin SHORT protection, SCP protection. The protection of FB overshoot and OVP protection as below: LATCHTIME = 218 x RRT R [k] [S ] = 262144 x RT 10 1.5 x 10 1.5 x 10 7 Clock oscillation of timer latch uses DCDC clock. So timer latch time depend on unevenness of DCDC oscillation. In 150kHz, timer latch time is 5% unevenness. Setting Example In LED_OPEN protection, LED_SHORT protection, SCP protection, When RT resistance=100kohm, the timer latch time is LATCH TIME = 65536 x R RT [k] 1.5 x10 7 = 65536 x 100[k] = 0.437[ S ] 1.5 x10 7 And, FB overshoot protection, OVP protection is LATCH TIME = 524288 x R RT [k] 100[k] = 262144 x = 1.75[S ] 1.5 x 10 7 1.5 x 10 7 LED1 SHORT Pro. detect 12V CP COUNTER 65536 65534 3 1 Oscllator (internal IC) 65535 0.8V 2 LED1_Voltage 0V CP COUNT UP END CP COUNT UP START I_LED1 Current LED1 LATCH UP FAIL (OPEN) LOW FAIL DET Figure 31. Timing chart of LSP time latch www.rohm.com (c) 2013 ROHM Co., Ltd. All rights reserved. TSZ2211115001 27/35 TSZ02201-0F10C1002000-1-2 19.Oct.2013 Rev.003 BD9470AFMBD9470AEFV 3.2 Selection of DCDC components OCP setting procedure/DCDC component current tolerance selection procedure The OCP detection function that is one of the functions of the CS pin will stop the DC/DC converter operating if the CS pin voltage becomes greater than 0.4V. Consequently, it is needed to calculate a peak current flowing through the coilL and then review the resistance of RCS. Furthermore, a current tolerance for DC/DC components should be larger than that for peak current flowing through the coil L. The following section describes the peak coil current calculation procedure, CS pin connection resistor RCS selection procedure, and DC/DC component current tolerance selection procedure I IN = VOUT [V ] x I OUT [ A] [ A] VIN [V ] x[%] N CS Rcs Further, according to drive operation with the DC/DC converter switching frequency fsw [Hz], inductor ripple current IL [A] generated at the inductor L is given by the following equation. IL = IOUT(total) Calculation of coil current Ipeak Ripple voltage generated at the CS pin is determined by conditions for DC/DC application components. Assuming the conditions: L VOUT output voltage=VOUT [V] LED total current=IOUT [A] VIN IL DCDC input voltage=VIN [V] DCDC efficiency= [%] mean input current IIN required for the whole system is given by the following fsw equation DCDC_GND (VOUT [V ] - V IN [V ]) x V IN [V ] [ A] L[ H ] x VOUT [V ] x f SW [ Hz ] As a result, the peak current Ipeak of IL is given by the following equation. IL[ A] [ A](1) 2 (V) CS pin connection resistor RCS selection procedure The current Ipeak flows into RCS to generate voltage.(See timing chart shown to the right.) The voltage VCSpeak is given by the following equation. N[V] Ipeak = I IN [ A] + VCS peak = Rcs x Ipeak [V ] A) (t) Ipeak Rcs[] x Ipeak[ A] < 0.4[V ] V) Imin (t) Iocp current needed for OCP detection voltage CS to reach 0.4V is given by the following equation 0.4[V ] [ A](2) Rcs[] VCS[V] 0.5V DCDC component current tolerance selection procedure I ocp = IL IIN IL[A] If this VCSpeak voltage reaches 0.4V, DC/DC output will stop. Consequently, to select RCS resistance, the following condition should be met. VCSpeak (t) Figure32. The relation among Ipeak current (Equation (1)), Iocp current (Equation (2)), DCDCapplication diagram and coil current I peak < I ocp < Max. current tolerance for component DC/DC application components including FETs, inductors, and diodes should be selected so that the Equation shown above will be met. Furthermore, it is recommended to normally use DC/DC application components in continuous mode. Assuming that the lower limit value of coil ripple current is Imin, the following equation should be met IL[ A] [ A] > 0 2 A failure to meet this condition is referred to as discontinuous mode. Im in = I IN [ A] - www.rohm.com (c) 2013 ROHM Co., Ltd. All rights reserved. TSZ2211115001 28/35 TSZ02201-0F10C1002000-1-2 19.Oct.2013 Rev.003 BD9470AFMBD9470AEFV Setting example Output voltage=VOUT [V]=40V LED total current=IOUT [A]=120mAx6ch=0.72A DCDC input voltage=VIN [V]=24V DCDC efficiency=[%]=90% mean input current IIN required for the whole system is given by the following equation I IN [ A] = VOUT [V ] x I OUT [ A] 40[V ] x 0.72[ A] = = 1.33 [ A] V IN [V ] x[%] 24[V ] x 90[%] DCDC switching frequency=fsw[Hz]=200kHz Inductor L[H]=47H The Inductor ripple currentIL[A] is: IL = (VOUT [V ] - VIN [V ]) x VIN [V ] (40[V ] - 24[V ]) x 24[V ] = = 1.02 [ A] L[ H ] x VOUT [V ] x f SW [ Hz ] 47 x10 -6 [ H ] x 40[V ] x 200 x10 3 [ Hz ] As a result, the IL peak current Ipeak is: Ipeak = I IN [ A] + IL[ A] 1.02[ A] [ A] = 1.33[ A] + = 1.84 [ A] 2 2 ... Result of peak current calculation When RCS resistance is set to 0.15ohm, the VCS peak voltage will be given by the following equation VCS peak = Rcs x Ipeak = 0.15[] x 1.84[ A] = 0.276[V ] < 0.5V ... Result of review of RCS resistance Consequently, the result meets the condition. Furthermore, IOCP current at which OCP is detected is given by the following equation I ocp = 0.4[V ] = 2.67 [ A] 0.15[] If the current tolerance for components to be used (e.g. FETs, inductors, diodes) is smaller than 2.5A, I peak < I OCP < Max. Current tolerance for component = 1.84[ A] < 2.67[ A] < 3.0[ A] ... Result of review of current tolerance for DC/DC components As a result, since the condition above is met, the selection of components is accepted. And, the lower limit of IL ripple current Imin is: Im in = I IN [ A] - IL[ A] 1.02[ A] [ A] = 1.33[ A] - = 0.82[ A] > 0 2 2 The system will not be put into discontinuous mode. To select DC/DC components, please consider IC variations as well as individual component variations, andthen conduct thorough verification on practical systems. www.rohm.com (c) 2013 ROHM Co., Ltd. All rights reserved. TSZ2211115001 29/35 TSZ02201-0F10C1002000-1-2 19.Oct.2013 Rev.003 BD9470AFMBD9470AEFV Selection of Inductor The value of inductor has significant influence on the input ripple current. As shown by Equation (1), the larger the inductor and the higher the switching frequency, the inductor ripple current IL becomes increasingly lower. IL = (VOUT - V IN ) x V IN [ A] (1) L x VOUT x f SW Efficiency as shown by Equation (2), peak input current is given as Equation = VOUT x I OUT (2) VIN x I IN ILMAX = I IN + (3). IL VIN IL VOUT x I OUT IL = + (3) 2 VIN x 2 IL L Here, LReactance value [H] VOUTDC/DC output voltage[V] IOUToutput current(LED total current)[A] VINinput voltage[V] IINinput current[A] FSWoscillation frequency[Hz] If a current in excess of the rated current of the inductor applies to the coil, the inductor will cause magnetic saturation, resulting in lower efficiency. Select an inductor with an adequate margin so that peak current will not exceed the rated current of the inductor. To reduce power dissipation from and increase efficiency of induct or, select an inductor with low resistance component (DCR or AC R). VOUT RCS COUT Figure33. DCDC application circuit and coil current Selection of switching MOSFET transistors There will be no problem for switching MOSFET transistors having absolute maximum rating higher than rated current of the inductor L and VF higher than "COUT breakdown voltage + Rectifier diode". However, to achieve high-speed switching, select transistors with small gate capacity (injected charge amount). Rated current larger than current protection setting current is recommended Selecting transistors with low On resistance can obtain high efficiency. Selection of rectifier diodes Select current capability higher than the rated current of the inductor L and inverse breakdown voltage higher that COUT break-down voltage, particularly having low forward voltage VF. www.rohm.com (c) 2013 ROHM Co., Ltd. All rights reserved. TSZ2211115001 30/35 TSZ02201-0F10C1002000-1-2 19.Oct.2013 Rev.003 BD9470AFMBD9470AEFV 3.3 Timing Chart VCC 7.5V 2.0V 0.8V STB REG58 2.4V 2.6V GND FAIL ( normal state ) 1.5V ISET RT 3.7V SS SS=FB or LED feed-back FB LED feed-back VOUT 1.5V PWM 0.8V ILED LED_OPEN LED_SHORT Disaable Disaable LED_GND_SHORT Enable Enable ISET_GND_SHORT RT_GND_SHORT Disaable Enable UVLO REG58_UVLO VCC_UVLO Disaable Enable Disaable Enable OVP SCP Disaable Disaable Disaable Disaable Disaable Figure 34. Timing Chart www.rohm.com (c) 2013 ROHM Co., Ltd. All rights reserved. TSZ2211115001 31/35 TSZ02201-0F10C1002000-1-2 19.Oct.2013 Rev.003 BD9470AFMBD9470AEFV 3.4 List of Protection Functions List of protection detecting condition Protection names Detection pin LED OPEN LED LEDSHORT LED Detection condition Detection pin PWM condition LEDx < 0.20V SS Release condition H SS>3.7V LEDx > 0.20V H SS>3.7V H SS>3.7V LEDx > 9V LED GND SHORT ISET GND SHORT RT GND SHORT Timer 2 16 count 2 16 count LEDx < 9V (LSP=OPEN) (LSP=OPEN) 16 LED LEDx < 0.20V ISET Under ISETx90% RT Under RTx90% - - UVLO UVLO UVLO<2.7V - - UVLO>3V REG58 UVLO REG58 REG58<2.4V - - REG58>2.6V VCC UVLO VCC VCC<7.2V - - VCC>7.5V LEDx > 0.20V Canceled ISET=GND State Canceled RT=GND State OVP OVP OVP>3.0V - - OVP<2.9V 2 SCP OVP OVP<0.1V - - OVP>0.1V 2 16 OCP CS OCP>0.4V - - - Latch (Only detected ) Latch (Only detected ) 7 2 +2 count Immediately detect Immediately detect Immediately detect Immediately detect Immediately detect 18 Protection type Latch Auto-restart Auto-restart Auto-restart Auto-restart Auto-restart count Latch count Latch Immediately detect Pulse-by-Pulse * To clear the latch type, STB should be set to "L" once, and then to "H" * The count of Timer means " 1count = 1 duty of switching frequency. List of protection detecting operation Protection Functions Operation when the hysteresis type protection is detected DC/DC LED OPEN Continues operation LEDSHORT Continues operation LED GNDSHORT ISET GND SHORT RT GND SHORT STB UVLO REG58 UVLO VCC UVLO OVP SCP OCP Stops operating after CP counting Instantaneously stops operating Instantaneously stops operating Instantaneously stops operating Instantaneously stops operating Instantaneously stops operating Instantaneously stops operating Stops operating after CP counting Stops operating after CP counting limits duty cycle www.rohm.com (c) 2013 ROHM Co., Ltd. All rights reserved. TSZ2211115001 LED Driver Only detected LED stops operating after CP counting Only detected LED stops operating after CP counting Not discharged Stops operating after CP counting Discharge Instantaneously stops operating Not discharged Normal Operation Not discharged Stops (and REG58<2.4V) Discharge Instantaneously stops operating Discharge Instantaneously stops operating Discharge Instantaneously stops operating Discharge Stops operating after CP counting Discharge Stops operating after CP counting Discharge Continues operation Not discharged 32/35 Soft start Not discharged FAIL pin Open after CP counting Open after CP counting Open after CP counting OPEN immediately LOW OPEN immediately OPEN immediately OPEN immediately OPEN immediately Open after CP counting Open after CP counting LOW TSZ02201-0F10C1002000-1-2 19.Oct.2013 Rev.003 BD9470AFMBD9470AEFV 4. Caution on use 1.) We pay utmost attention to the quality control of this product. However, if it exceeds the absolute maximum ratin gs including applied voltage and operating temperature range, it may lead to its deterioration or breakdown. Furth er, this makes it impossible to assume a breakdown state such as short or open circuit mode. If any special mod e to exceed the absolute maximum ratings is assumed, consider adding physical safety measures such as fuses. 2.) Making a reverse connection of the power supply connector can cause the IC to break down. To protect the IC f orm breakdown due to reverse connection, take preventive measures such as inserting a diode between the exter nal power supply and the power supply pin of the IC. 3.) Since current regenerated by back electromotive force flows back, take preventive measures such as inserting a c apacitor between the power supply and the ground as a path of the regenerative current and fully ensure that ca pacitance presents no problems with characteristics such as lack of capacitance of electrolytic capacitors causes a t low temperatures, and then determine the power supply line. Provide thermal design having an adequate margin in consideration of power dissipation (Pd) in the practical operating conditions. 4.) The potential of the GND pin should be maintained at the minimum level in any operating state. 5.) Provide thermal design having an adequate margin in consideration of power dissipation (Pd) in the practical oper ating conditions. To mount the IC on a printed circuit board, pay utmost attention to the direction and displacement of the IC. Furthermore, the IC may get damaged if it is mounted in an erroneous manner or if a short circuit is established due to foreign matters entered between output pins or between output pin and power supply GND pin. 6.) Note that using this IC in strong magnetic field may cause it to malfunction. 7.) Please set the output Tr not to over absolute Maximum Ratings and ASO. CMOS IC and plural power supply IC have a possible to flow lush current momentarily. Please note VCC capacitor, VCC and GND layout. 8.) This IC has a built-in thermal-protection circuit (TSD circuit). The thermal-protection circuit (TSD circuit) is a circuit absolutely intended to protect the IC from thermal runaway, not intended to protect or guarantee the IC. Consequently, do not use the IC based on the activation of this TS D circuit for subsequent continuous use and operation of the IC. 9.) When testing the IC on a set board with a capacitor connected to the pin, the IC can be subjected to stress. In this case, be sure to discharge the capacitor for each process. In addition, to connect the IC to a jig up to the t esting process, be sure to turn OFF the power supply prior to connection, and disconnect the jig only after turnin g OFF the power supply. 10.) This monolithic IC contains P + Isolation and P substrate layers between adjacent elements in order to keep them isolated. P-N junctions are formed at the intersections of these P layers and the N layers of other elements, thus making up different types of parasitic elements. For example, if a resistor and a transistor is connected with pins respectively as shown in Fig. When GND>(Pin A) for the resistor, or when GND>(Pin B) for the transistor (NPN), P-N junctions operate as a a parasitic diode. When GND>(Pin B) for the transistor (NPN), the parasitic NPN transistor operates by the N layer of other element adjacent to the parasitic diode aforementioned. Due to the structure of the IC, parasitic elements are inevitably formed depending on the relationships of potential. The operation of parasitic diodes can result in interferences in circuit operation, leading to malfunctions and eventually breakdown of the IC. Consequently, pay utmost attention not to use the IC for any applications by which the parasitic elements are operated, such as applying a voltage lower than that of GND (P substrate) to the input pin. Transistor (NPN) Resistor (Pin A) N P P P N B C (Pin B) N P N E GND P P N N N P substrate P substrate GND Parasitic element GND Parasitic element (Pin B) (Pin A) B Parasitic element GND C E Adjacent other elements Parasitic Figure 35. Example of Simple Structure of Monolithic IC Status of this document The Japanese version of this document is formal specification. A customer may use this translation version only for a reference to help reading the formal version. If there are any differences in translation version of this document formal version takes priority www.rohm.com (c) 2013 ROHM Co., Ltd. All rights reserved. TSZ2211115001 33/35 TSZ02201-0F10C1002000-1-2 19.Oct.2013 Rev.003 BD9470AFMBD9470AEFV Ordering Information B D 9 4 7 0 Part Number B D A F M E2 Package FM: HSOP-M 9 4 7 Part Number 0 A E Packaging and forming specification E2: Embossed tape and reel F Package EFV: HTSSOP-B V E2 Packaging and forming specification E2: Embossed tape and reel Physical Dimension Tape and Reel Information www.rohm.com (c) 2013 ROHM Co., Ltd. All rights reserved. TSZ2211115001 34/35 TSZ02201-0F10C1002000-1-2 19.Oct.2013 Rev.003 BD9470AFMBD9470AEFV 6. Revision history Date Revision 26.Oct.2012 001 09.Jan.2013 19.Oct.2013 Changes New Release 002 P6 / Verified minimum ISET resistor 002 P10 / Verified ISET terminal instruction 002 P23 / Verified LED Current setting 003 P2 / Change Pin Configuration 003 P1 / Delete PbFree, RoHS 003 ADD NOTICE www.rohm.com (c) 2013 ROHM Co., Ltd. All rights reserved. TSZ2211115001 35/35 TSZ02201-0F10C1002000-1-2 19.Oct.2013 Rev.003 Datasheet Notice Precaution on using ROHM Products 1. Our Products are designed and manufactured for application in ordinary electronic equipments (such as AV equipment, OA equipment, telecommunication equipment, home electronic appliances, amusement equipment, etc.). If you (Note 1) , transport intend to use our Products in devices requiring extremely high reliability (such as medical equipment equipment, traffic equipment, aircraft/spacecraft, nuclear power controllers, fuel controllers, car equipment including car accessories, safety devices, etc.) and whose malfunction or failure may cause loss of human life, bodily injury or serious damage to property ("Specific Applications"), please consult with the ROHM sales representative in advance. Unless otherwise agreed in writing by ROHM in advance, ROHM shall not be in any way responsible or liable for any damages, expenses or losses incurred by you or third parties arising from the use of any ROHM's Products for Specific Applications. (Note1) Medical Equipment Classification of the Specific Applications JAPAN USA EU CHINA CLASS CLASSb CLASS CLASS CLASS CLASS 2. ROHM designs and manufactures its Products subject to strict quality control system. However, semiconductor products can fail or malfunction at a certain rate. Please be sure to implement, at your own responsibilities, adequate safety measures including but not limited to fail-safe design against the physical injury, damage to any property, which a failure or malfunction of our Products may cause. The following are examples of safety measures: [a] Installation of protection circuits or other protective devices to improve system safety [b] Installation of redundant circuits to reduce the impact of single or multiple circuit failure 3. Our Products are designed and manufactured for use under standard conditions and not under any special or extraordinary environments or conditions, as exemplified below. Accordingly, ROHM shall not be in any way responsible or liable for any damages, expenses or losses arising from the use of any ROHM's Products under any special or extraordinary environments or conditions. If you intend to use our Products under any special or extraordinary environments or conditions (as exemplified below), your independent verification and confirmation of product performance, reliability, etc, prior to use, must be necessary: [a] Use of our Products in any types of liquid, including water, oils, chemicals, and organic solvents [b] Use of our Products outdoors or in places where the Products are exposed to direct sunlight or dust [c] Use of our Products in places where the Products are exposed to sea wind or corrosive gases, including Cl2, H2S, NH3, SO2, and NO2 [d] Use of our Products in places where the Products are exposed to static electricity or electromagnetic waves [e] Use of our Products in proximity to heat-producing components, plastic cords, or other flammable items [f] Sealing or coating our Products with resin or other coating materials [g] Use of our Products without cleaning residue of flux (even if you use no-clean type fluxes, cleaning residue of flux is recommended); or Washing our Products by using water or water-soluble cleaning agents for cleaning residue after soldering [h] Use of the Products in places subject to dew condensation 4. The Products are not subject to radiation-proof design. 5. Please verify and confirm characteristics of the final or mounted products in using the Products. 6. In particular, if a transient load (a large amount of load applied in a short period of time, such as pulse. is applied, confirmation of performance characteristics after on-board mounting is strongly recommended. Avoid applying power exceeding normal rated power; exceeding the power rating under steady-state loading condition may negatively affect product performance and reliability. 7. De-rate Power Dissipation (Pd) depending on Ambient temperature (Ta). When used in sealed area, confirm the actual ambient temperature. 8. Confirm that operation temperature is within the specified range described in the product specification. 9. ROHM shall not be in any way responsible or liable for failure induced under deviant condition from what is defined in this document. Precaution for Mounting / Circuit board design 1. When a highly active halogenous (chlorine, bromine, etc.) flux is used, the residue of flux may negatively affect product performance and reliability. 2. In principle, the reflow soldering method must be used; if flow soldering method is preferred, please consult with the ROHM representative in advance. For details, please refer to ROHM Mounting specification Notice - GE (c) 2014 ROHM Co., Ltd. All rights reserved. Rev.002 Datasheet Precautions Regarding Application Examples and External Circuits 1. If change is made to the constant of an external circuit, please allow a sufficient margin considering variations of the characteristics of the Products and external components, including transient characteristics, as well as static characteristics. 2. You agree that application notes, reference designs, and associated data and information contained in this document are presented only as guidance for Products use. Therefore, in case you use such information, you are solely responsible for it and you must exercise your own independent verification and judgment in the use of such information contained in this document. ROHM shall not be in any way responsible or liable for any damages, expenses or losses incurred by you or third parties arising from the use of such information. Precaution for Electrostatic This Product is electrostatic sensitive product, which may be damaged due to electrostatic discharge. Please take proper caution in your manufacturing process and storage so that voltage exceeding the Products maximum rating will not be applied to Products. Please take special care under dry condition (e.g. Grounding of human body / equipment / solder iron, isolation from charged objects, setting of Ionizer, friction prevention and temperature / humidity control). Precaution for Storage / Transportation 1. Product performance and soldered connections may deteriorate if the Products are stored in the places where: [a] the Products are exposed to sea winds or corrosive gases, including Cl2, H2S, NH3, SO2, and NO2 [b] the temperature or humidity exceeds those recommended by ROHM [c] the Products are exposed to direct sunshine or condensation [d] the Products are exposed to high Electrostatic 2. Even under ROHM recommended storage condition, solderability of products out of recommended storage time period may be degraded. It is strongly recommended to confirm solderability before using Products of which storage time is exceeding the recommended storage time period. 3. Store / transport cartons in the correct direction, which is indicated on a carton with a symbol. Otherwise bent leads may occur due to excessive stress applied when dropping of a carton. 4. Use Products within the specified time after opening a humidity barrier bag. Baking is required before using Products of which storage time is exceeding the recommended storage time period. Precaution for Product Label QR code printed on ROHM Products label is for ROHM's internal use only. Precaution for Disposition When disposing Products please dispose them properly using an authorized industry waste company. Precaution for Foreign Exchange and Foreign Trade act Since our Products might fall under controlled goods prescribed by the applicable foreign exchange and foreign trade act, please consult with ROHM representative in case of export. Precaution Regarding Intellectual Property Rights 1. All information and data including but not limited to application example contained in this document is for reference only. ROHM does not warrant that foregoing information or data will not infringe any intellectual property rights or any other rights of any third party regarding such information or data. ROHM shall not be in any way responsible or liable for infringement of any intellectual property rights or other damages arising from use of such information or data.: 2. No license, expressly or implied, is granted hereby under any intellectual property rights or other rights of ROHM or any third parties with respect to the information contained in this document. Other Precaution 1. This document may not be reprinted or reproduced, in whole or in part, without prior written consent of ROHM. 2. The Products may not be disassembled, converted, modified, reproduced or otherwise changed without prior written consent of ROHM. 3. In no event shall you use in any way whatsoever the Products and the related technical information contained in the Products or this document for any military purposes, including but not limited to, the development of mass-destruction weapons. 4. The proper names of companies or products described in this document are trademarks or registered trademarks of ROHM, its affiliated companies or third parties. Notice - GE (c) 2014 ROHM Co., Ltd. All rights reserved. Rev.002 Datasheet General Precaution 1. Before you use our Pro ducts, you are requested to care fully read this document and fully understand its contents. ROHM shall n ot be in an y way responsible or liabl e for fa ilure, malfunction or acci dent arising from the use of a ny ROHM's Products against warning, caution or note contained in this document. 2. All information contained in this docume nt is current as of the issuing date and subj ect to change without any prior notice. Before purchasing or using ROHM's Products, please confirm the la test information with a ROHM sale s representative. 3. The information contained in this doc ument is provi ded on an "as is" basis and ROHM does not warrant that all information contained in this document is accurate an d/or error-free. ROHM shall not be in an y way responsible or liable for an y damages, expenses or losses incurred b y you or third parties resulting from inaccur acy or errors of or concerning such information. Notice - WE (c) 2014 ROHM Co., Ltd. All rights reserved. Rev.001 Datasheet bd9470aefv - Web Page Buy Distribution Inventory Part Number Package Unit Quantity Minimum Package Quantity Packing Type Constitution Materials List RoHS bd9470aefv HTSSOP-B28 2500 2500 Taping inquiry Yes