TEA1791T GreenChip synchronous rectifier controller Rev. 02 -- 7 June 2010 Product data sheet 1. General description The TEA1791T is a member of the new generation of Synchronous Rectifier (SR) controller ICs for switched mode power supplies. Its high level of integration allows the design of a cost-effective power supply with a very low number of external components. The TEA1791T is a controller IC dedicated to synchronous rectification on the secondary side of discontinuous conduction mode and quasi-resonant flyback converters. The TEA1791T is fabricated in a Silicon On Insulator (SOI) process. 2. Features and benefits 2.1 Distinctive features Accurate synchronous rectification functionality Wide supply voltage range (8.5 V to 38 V) High level of integration, resulting in a very low external component count High driver output voltage of 10 V to drive all MOSFET brands to the lowest RDSon 2.2 Green features Low current consumption High system efficiency from no load to full load 2.3 Protection features Undervoltage protection 3. Applications The TEA1791T is intended for adapters. The device can also be used in all other discontinuous conduction mode systems and quasi-resonant flyback systems that demand a highly efficient and cost-effective solution. 4. Ordering information Table 1. Ordering information Type number TEA1791T/N1 Package Name Description Version SO8 plastic small outline package; 8 leads; body width 3.9 mm SOT96-1 TEA1791T NXP Semiconductors GreenChip synchronous rectifier controller 5. Block diagram VCC 8 SRSENSE 1 control Q R DRIVER TIMER 2 s 4 Q S 2.2 s -310 mV 3, 5, 6, 7 -55 mV 2 n.c. Fig 1. -12 mV GND 014aaa700 Block diagram 6. Pinning information 6.1 Pinning SRSENSE 1 GND 2 8 VCC 7 n.c. TEA1791T n.c. 3 6 n.c. DRIVER 4 5 n.c. 014aaa701 Fig 2. Pin configuration 6.2 Pin description Table 2. TEA1791T Product data sheet Pin description Symbol Pin Description SRSENSE 1 synchronous timing input GND 2 ground n.c. 3 not connected DRIVER 4 driver output for SR MOSFET n.c 5 not connected n.c. 6 not connected n.c. 7 not connected VCC 8 supply voltage All information provided in this document is subject to legal disclaimers. Rev. 02 -- 7 June 2010 (c) NXP B.V. 2010. All rights reserved. 2 of 12 TEA1791T NXP Semiconductors GreenChip synchronous rectifier controller 7. Functional description 7.1 Introduction The TEA1791T is the controller for synchronous rectification to be used in discontinuous conduction mode and quasi-resonant flyback converters. 7.2 Start-up and UnderVoltage LockOut (UVLO) The IC leaves the undervoltage lockout state and activates the synchronous rectifier circuitry as soon as the voltage on the VCC pin is above 8.5 V (typical). When the voltage drops below 8.0 V (typical), the undervoltage lockout state is reentered and the SR driver output is actively kept low. 7.3 Synchronous rectification After a negative voltage (-310 mV typical) is sensed on the SRSENSE pin, the driver output voltage is driven HIGH and the external MOSFET is switched on. As soon as the SRSENSE voltage rises to -55 mV the driver output voltage is regulated to maintain the -55 mV on the SRSENSE pin. When the SRSENSE voltage is above -12 mV, the driver output is pulled to ground. After switch-on of the SR MOSFET, the input signal on the SRSENSE pin is blanked for 2 s (typical). This eliminates false switch-off due to high frequency ringing at the start of the secondary stroke. Because the driver output voltage is reduced when the voltage on the SRSENSE pin is -55 mV, the external power switch can be switched off quickly when the current through the switch reaches zero. The zero current switch-off removes the need for a separate Standby mode to maintain high efficiency during the no-load operation. The zero current is detected by sensing a -12 mV level on the SRSENSE pin (see Figure 3). TEA1791T Product data sheet All information provided in this document is subject to legal disclaimers. Rev. 02 -- 7 June 2010 (c) NXP B.V. 2010. All rights reserved. 3 of 12 TEA1791T NXP Semiconductors GreenChip synchronous rectifier controller VSRSENSE 0V -12 mV -55 mV -310 mV Primary current 0A Secondary current 0A VDRIVER 0V 014aaa057 Fig 3. Synchronous rectification signals If the secondary stroke of the flyback converter is shorter than 2 s (typical), the driver output is disabled. This will guarantee stable operation for very low duty cycles. When the secondary stroke increases above 2.2 s (typical), the driver output is again enabled. 7.4 Supply management All internal reference voltages are derived from a temperature compensated, on-chip band gap circuit. 7.5 Driver The driver circuit to the gate of the external power MOSFET has a typical source capability of 250 mA and a typical sink capability of 2.7 A. This permits fast turn-on and turn-off of the power MOSFET for efficient operation. The output voltage of the driver is limited to 10 V (typical). This high output voltage will drive all MOSFET brands to the minimum on-state resistance. During start-up conditions (VCC < Vstartup) and undervoltage lockout the driver output voltage is actively pulled low. TEA1791T Product data sheet All information provided in this document is subject to legal disclaimers. Rev. 02 -- 7 June 2010 (c) NXP B.V. 2010. All rights reserved. 4 of 12 TEA1791T NXP Semiconductors GreenChip synchronous rectifier controller 8. Limiting values Table 3. Limiting values In accordance with the Absolute Maximum Rating System (IEC 60134). All voltages are measured with respect to ground (pin 2); positive currents flow into the chip. The voltage ratings and current ratings are valid provided the other ratings are not violated. Symbol Parameter Conditions Min Max Unit VCC supply voltage continuous -0.4 +38 V VSRSENSE voltage on pin SRSENSE continuous - 120 V IDRIVER current on pin DRIVER duty cycle < 10 % -0.8 +3 A ISRSENSE current on pin SRSENSE -3 - mA Voltages Currents General Tamb < 80 C Ptot total power dissipation - 0.45 W Tstg storage temperature -55 +150 C Tj junction temperature -40 +150 C VESD electrostatic discharge voltage class 2 human body model [1] - 2000 V machine model [2] - 200 V - 500 V charged device model [1] Equivalent to discharging a 100 pF capacitor through a 1.5 k series resistor. [2] Equivalent to discharging a 200 pF capacitor through a 0.75 H coil and a 10 series resistor. 9. Thermal characteristics Table 4. TEA1791T Product data sheet Thermal characteristics Symbol Parameter Conditions Typ Unit Rth(j-a) thermal resistance from junction to ambient in free air 150 K/W Rth(j-c) thermal resistance from junction to case 95 K/W All information provided in this document is subject to legal disclaimers. Rev. 02 -- 7 June 2010 (c) NXP B.V. 2010. All rights reserved. 5 of 12 TEA1791T NXP Semiconductors GreenChip synchronous rectifier controller 10. Characteristics Table 5. Characteristics Tamb = 25 C; VCC = 20 V; all voltages are measured with respect to ground (pin 2); currents are positive when flowing into the IC; unless otherwise specified. Symbol Parameter Conditions Min Typ Max Unit 8.2 8.5 8.8 V - 0.5 - V - 0.65 - mA - 0.95 - mA -310 -280 mV Supply voltage management (pin VCC) Vstartup start-up voltage [1] Vhys hysteresis voltage ICC(oper) operating supply current VCC = 8 V (VCC < Vstartup) under normal operation; no load on pin DRIVER Synchronous rectification sense input (pin SRSENSE) Vact(drv) driver activation voltage -340 Vreg(drv) driver regulation voltage -65 -55 -45 mV Vdeact(drv) driver deactivation voltage - -12 - mV td(act)(drv) driver activation delay time - 125 - ns tact(sr)(min) minimum synchronous rectification Short time 1.5 2.0 2.5 s Long time 1.7 2.2 2.7 s -0.3 -0.25 -0.2 A voltage on pin DRIVER = 2 V 1 1.4 - A voltage on pin DRIVER = 9.5 V 2.2 2.7 - A - 10 12 V Driver (pin DRIVER) Isource source current VCC = 15 V; voltage on pin DRIVER = 2 V Isink sink current VCC = 15 V Vo(max) [1] maximum output voltage VCC = 15 V The VCC stop voltage is Vstartup - Vhys. TEA1791T Product data sheet All information provided in this document is subject to legal disclaimers. Rev. 02 -- 7 June 2010 (c) NXP B.V. 2010. All rights reserved. 6 of 12 TEA1791T NXP Semiconductors GreenChip synchronous rectifier controller 11. Application information A switched mode power supply with the TEA1791T consists of a primary side discontinuous conduction mode flyback controller, a transformer, and an output stage with a feedback circuit. A MOSFET (Qsec) is used for low conduction losses in the output state. This MOSFET is controlled by the TEA1791T. The timing for the synchronous rectifier switch is derived from the voltage sensed on the SRSENSE pin. The resistor in the SRSENSE connection is needed to protect the TEA1791T from excessive voltages. The RSRSENSE resistor should typically be 1 k. Higher values might impair correct timing, lower values may not provide sufficient protection. TR Qsec Vout RSRSENSE Vin GND Qprim PRIMARY SIDE CONTROLLER VCC DRIVER Cout TEA1791T SRSENSE 014aaa702 Fig 4. Application diagram high side rectification TR Vin Vout VCC RSRSENSE PRIMARY SIDE CONTROLLER Qprim Qsec SRSENSE TEA1791T Cout DRIVER GND 014aaa849 Fig 5. TEA1791T Product data sheet Application diagram low side rectification All information provided in this document is subject to legal disclaimers. Rev. 02 -- 7 June 2010 (c) NXP B.V. 2010. All rights reserved. 7 of 12 TEA1791T NXP Semiconductors GreenChip synchronous rectifier controller 12. Package outline SO8: plastic small outline package; 8 leads; body width 3.9 mm SOT96-1 D E A X c y HE v M A Z 5 8 Q A2 A (A 3) A1 pin 1 index Lp 1 L 4 e detail X w M bp 0 2.5 5 mm scale DIMENSIONS (inch dimensions are derived from the original mm dimensions) UNIT A max. A1 A2 A3 bp c D (1) E (2) e HE L Lp Q v w y Z (1) mm 1.75 0.25 0.10 1.45 1.25 0.25 0.49 0.36 0.25 0.19 5.0 4.8 4.0 3.8 1.27 6.2 5.8 1.05 1.0 0.4 0.7 0.6 0.25 0.25 0.1 0.7 0.3 0.069 0.010 0.057 0.004 0.049 0.01 0.019 0.0100 0.014 0.0075 0.20 0.19 0.16 0.15 0.05 0.01 0.01 0.004 0.028 0.012 inches 0.244 0.039 0.028 0.041 0.228 0.016 0.024 o 8 o 0 Notes 1. Plastic or metal protrusions of 0.15 mm (0.006 inch) maximum per side are not included. 2. Plastic or metal protrusions of 0.25 mm (0.01 inch) maximum per side are not included. Fig 6. REFERENCES OUTLINE VERSION IEC JEDEC SOT96-1 076E03 MS-012 JEITA EUROPEAN PROJECTION ISSUE DATE 99-12-27 03-02-18 Package outline SOT96-1 (SO8) TEA1791T Product data sheet All information provided in this document is subject to legal disclaimers. Rev. 02 -- 7 June 2010 (c) NXP B.V. 2010. All rights reserved. 8 of 12 TEA1791T NXP Semiconductors GreenChip synchronous rectifier controller 13. Revision history Table 6. Revision history Document ID Release date Data sheet status Change notice Supersedes TEA1791T v.2 20100607 Product data sheet - TEA1791T_1 Modifications: TEA1791T_1 TEA1791T Product data sheet * * * Rth(j-c) added to Table 4. Figure 5 "Application diagram low side rectification", added. Minimum value junction temperature changed in Table 3. 20090203 Product data sheet - All information provided in this document is subject to legal disclaimers. Rev. 02 -- 7 June 2010 - (c) NXP B.V. 2010. All rights reserved. 9 of 12 TEA1791T NXP Semiconductors GreenChip synchronous rectifier controller 14. Legal information 14.1 Data sheet status Document status[1][2] Product status[3] Definition Objective [short] data sheet Development This document contains data from the objective specification for product development. Preliminary [short] data sheet Qualification This document contains data from the preliminary specification. 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All rights reserved. 10 of 12 TEA1791T NXP Semiconductors GreenChip synchronous rectifier controller Non-automotive qualified products -- Unless this data sheet expressly states that this specific NXP Semiconductors product is automotive qualified, the product is not suitable for automotive use. It is neither qualified nor tested in accordance with automotive testing or application requirements. NXP Semiconductors accepts no liability for inclusion and/or use of non-automotive qualified products in automotive equipment or applications. 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Contact information For more information, please visit: http://www.nxp.com For sales office addresses, please send an email to: salesaddresses@nxp.com TEA1791T Product data sheet All information provided in this document is subject to legal disclaimers. Rev. 02 -- 7 June 2010 (c) NXP B.V. 2010. All rights reserved. 11 of 12 TEA1791T NXP Semiconductors GreenChip synchronous rectifier controller 16. Contents 1 2 2.1 2.2 2.3 3 4 5 6 6.1 6.2 7 7.1 7.2 7.3 7.4 7.5 8 9 10 11 12 13 14 14.1 14.2 14.3 14.4 15 16 General description . . . . . . . . . . . . . . . . . . . . . . 1 Features and benefits . . . . . . . . . . . . . . . . . . . . 1 Distinctive features . . . . . . . . . . . . . . . . . . . . . . 1 Green features . . . . . . . . . . . . . . . . . . . . . . . . . 1 Protection features . . . . . . . . . . . . . . . . . . . . . . 1 Applications . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1 Ordering information . . . . . . . . . . . . . . . . . . . . . 1 Block diagram . . . . . . . . . . . . . . . . . . . . . . . . . . 2 Pinning information . . . . . . . . . . . . . . . . . . . . . . 2 Pinning . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2 Pin description . . . . . . . . . . . . . . . . . . . . . . . . . 2 Functional description . . . . . . . . . . . . . . . . . . . 3 Introduction. . . . . . . . . . . . . . . . . . . . . . . . . . . . 3 Start-up and UnderVoltage LockOut (UVLO) . . 3 Synchronous rectification . . . . . . . . . . . . . . . . . 3 Supply management. . . . . . . . . . . . . . . . . . . . . 4 Driver . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 4 Limiting values. . . . . . . . . . . . . . . . . . . . . . . . . . 5 Thermal characteristics . . . . . . . . . . . . . . . . . . 5 Characteristics . . . . . . . . . . . . . . . . . . . . . . . . . . 6 Application information. . . . . . . . . . . . . . . . . . . 7 Package outline . . . . . . . . . . . . . . . . . . . . . . . . . 8 Revision history . . . . . . . . . . . . . . . . . . . . . . . . . 9 Legal information. . . . . . . . . . . . . . . . . . . . . . . 10 Data sheet status . . . . . . . . . . . . . . . . . . . . . . 10 Definitions . . . . . . . . . . . . . . . . . . . . . . . . . . . . 10 Disclaimers . . . . . . . . . . . . . . . . . . . . . . . . . . . 10 Trademarks. . . . . . . . . . . . . . . . . . . . . . . . . . . 11 Contact information. . . . . . . . . . . . . . . . . . . . . 11 Contents . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 12 Please be aware that important notices concerning this document and the product(s) described herein, have been included in section `Legal information'. (c) NXP B.V. 2010. All rights reserved. For more information, please visit: http://www.nxp.com For sales office addresses, please send an email to: salesaddresses@nxp.com Date of release: 7 June 2010 Document identifier: TEA1791T