Atmel LED Driver-MSLB9061
LED Driver Module
Compact, 6-channel LED Driver Board with I2C Interface
Datasheet
2 Atmel LED Driver-MSLB9061
Atmel LED Driver-MSLB9061
LED Driver Module
Compact, 6-channel LED Driver Board with I2C Interface
The optional microcontroller board and graphical user interface (GUI)
software allow control of the driver board through a personal computer. This
gives access to the internal features of the MSL1061, including fault detection,
digital control of LED current, individual LED string on/off control, and internally
generated PWM dimming.
The compact six-channel LED driver board is intended for evaluation,
prototyping, or production runs. Gerber files and Cadence OrCAD layout files
are available to allow the circuit to be integrated into a larger system for large
production runs.
Applications
• LCD Panel LED Backlight Driver
Ordering Information
PART DESCRIPTION
MSLB9061 Compact, 6-channel LED driver module
General Description
The Atmel® compact,
6-channel LED driver board is a
complete LED backlight driver
solution using the Atmel LED
Driver-MSL1061 LED driver
for medium-sized LCD panels.
Each channel drives up to 12
series-connected LEDs at up to
30mA per channel. The diver
board is configured to operate
from 3.3V up to 28V. The full-
scale LED current is preset to
15, 20, 25, or 30mA per LED
string, selected by an onboard
switch. Current can be
reduced from full-scale through
the I2C serial interface in 16
linear steps. Digital (PWM)
dimming is available through
an external signal or by using
the internal PWM generator via
the serial interface.
3Atmel LED Driver-MSLB9061
Atmel LED Driver-MSLB9061
LED Driver Module
Compact, 6-channel LED Driver Board with I2C InterfaceCompact, 6-channel LED Driver Board with I2C Interface
Key Features
LED Driver Board
• Drives up to 6 LED Strings
• Up to 12 LEDs per String
• Up to 30mA per LED String
• I²C Serial Interface
• Fault Detection and Protection
• 3.3 to 28V Input Voltage Range
• Up to 7.2W Output Power
• Small Size, 1.95” X 0.73”
• Four Available I²C Slave Addresses, Switch
Selectable
• Four Full-scale Current Settings, Switch Selectable
• Separate Bias and Power Inputs Allows a Variety
Of Configurations
• 1Mhz Switching Frequency
• Internal Or External PWM Dimming Control
• Digital Control of LED String Current
• Individual LED String On/Off Digital Control
• Short Circuit or Open Circuit LED String Detection
• Automatic Overvoltage Protection
1.95”
(49.53mm)
0.73”
(18.55mm)
4 Atmel LED Driver-MSLB9061
Mechanical Drawing
Figure 1. Atmel® LED Driver-MSLB9061 Mechanical Drawing. All Dimensions in Inches.
Connector Pin Descriptions
Table 1. J2 Input Connector Pin Descriptions
PIN NAME PIN NUMBER PIN DESCRIPTION
PWR 1,2 Input power to integrated boost regulator circuit
HVBIAS 3 Input to integrated LDO bias voltage regulator
LVBIAS 4 Input to MSL1061 bias voltage
DOUBLE 5 Input to charge pump doubler bias input
SDA 6 I²C serial data
SCL 7 I²C serial clock
FLTB 8 Fault indication output
EN 9 Enable control input
PWM 10 PWM dimming control input
GND 11,12 Ground
Table 2. J3 Output Connector Pin Descriptions
PIN NAME PIN NUMBER PIN DESCRIPTION
GND 1-8 Ground
STR6 9 LED string 6 cathode connection
STR5 10 LED string 5 cathode connection
STR4 11 LED string 4 cathode connection
STR3 12 LED string 3 cathode connection
STR2 13 LED string 2 cathode connection
STR1 14 LED string 1 cathode connection
VLED 15-20 LED sting anode output voltage
5Atmel LED Driver-MSLB9061
Absolute Maximum Ratings
Voltage (With Respect to GND)
STR1-STR6 ............................................................................................................................................................................................. -0.3V to +50V
VLED ............................................................................................................................................................................................................. -0.3V to +40V
PWR, HVBIAS ........................................................................................................................................................................................ -0.3V to +36V
BIAS, EN, PWM, SDA, SCL, FLTB ........................................................................................................................................ -0.3V to +5.5V
Ambient operating temperature range TA = TMIN to TMAX.................................................................................... -40°C to +50°C
Table 3 : Electrical Operating Characteristics
(Typical application circuit, VIN = 12V, TA = TMIN to TMAX, unless otherwise noted. Typical values are at TA = +25°C)
PARAMETER CONDITIONS AND NOTES MIN TYP MAX UNIT
DC ELECTRICAL CHARACTERISTICS
Power input voltage (Note 1) 3.3V 28 V
HVBIAS input voltage Bias voltage applied to HVBIAS, BIAS
unconnected 6.5 28 V
BIAS input voltage HVBIAS and BIAS inputs connected with bias
voltage applied 4.5 6 V
DOUBLE input voltage HVBIAS and BIAS inputs connected together,
bias voltage applied to DOUBLE 3.1 3.6 V
EN logic input high level 2.3 V
EN logic input low level 0.8 V
PWM, SDA, SCL input high voltage 2 V
PWM, SDA, SCL Input low voltage 0.9 V
FLTB output low voltage IFLTB = 1mA 0.1 V
FLTB leakage current VFLTB = 3.6V 1 A
STR1-STR6 output current
ISTRn = 0x0F, S2 position 1 30 mA
ISTRn = 0x0F, S2 position 2 25 mA
ISTRn = 0x0F, S2 position 3 15 mA
ISTRn = 0x0F, S2 position 4 10 mA
PARAMETER CONDITIONS AND NOTES MIN TYP MAX UNIT
AC ELECTRICAL CHARACTERISTICS
PWM input frequency 20 kHz
Atmel LED Driver-MSLB9061
LED Driver Module
Compact, 6-channel LED Driver Board with I2C Interface
6 Atmel LED Driver-MSLB9061
PARAMETER CONDITIONS AND NOTES MIN TYP MAX UNIT
I²C SWITCHING CHARACTERISTICS
SCL clock frequency I2C timeout disabled (Note 2) 1000 kHz
Bus timeout 25 ms
Bus free time between a STOP and START
condition 0.5 µs
Hold time for a repeated START condition 0.26 µs
Set-up time for a repeated START condition 0.26 µs
Set-up time for STOP condition 0.26 µs
Data hold time 10 ns
Data valid acknowledge time (Note 3) 0.05 0.45 µs
Data valid time (Note 4) 0.05 0.45 µs
Data set-up time 100 ns
LOW period of the SCL clock 0.5 µs
HIGH period of the SCL clock 0.26 µs
Fall time of SDA and SCL signals (Note 5,6) 120 ns
Rise time of both SDA and SCL signals 120 ns
Pulse width of spikes that must be
suppressed by the input lter (Note 7) 50 ns
SDA, SCL, AD0 input capacitance 10 pF
Note 1. Full power available with PWR input voltage greater than 6.5V. For 3.1V to 3.6V operation, doubling charge pump(U2)
and C12, C13 are required.
Note 2. Minimum SCL clock frequency is limited by the bus timeout feature, which resets the serial bus interface if either SDA or SCL
is held low for 25ms. Disable bus timeout feature for DC operation.
Note 3. Time for acknowledge signal from SCL low to SDA (out) low.
Note 4. Minimum time for SDA data out to be valid following SCL low.
Note 5. A master device must internally provide a hold time of at least 300ns for the SDA signal (refer to the VIL of the SCL signal)
in order to bridge the undefined region of SCL falling edge.
Note 6. The maximum fall times for the SDA and SCL bus lines are specified at 300ns. The maximum fall time for the SDA output
stage is specified at 250ns. This allows series protection resistors to be connected between SDA and SCL and the
SDA/SCL bus lines without exceeding the maximum specified tall time.
Note 7. Input filters on the SDA, SCL, and AD0 inputs suppress noise less than 50ns.
7Atmel LED Driver-MSLB9061
Efficiency at Vin = 12V
60
65
70
75
80
85
90
95
510 15 20 25 30
String Current (mA)
Efficiency (%)
Efficiency
Typical Performance Characteristics
Efficiency at Vin =5V
30
40
50
60
70
80
90
510 15 20 25 30
String Current (mA)
Efficiency (%)
Efficiency
Detailed Description
The MSLB9061 is a standalone, six-channel LED driver board suitable for integration into small production devices. It
includes an I2C serial interface for accessing the digital features of the MSL1061 LED driver. Onboard switches set the I2C
slave address to one of four available addresses and the full-scale LED current to 30, 25, 15, or 10mA.
Input Power
The MSLB9061 board is powered from input voltages ranging from 3.3 up to 28V, and the integral boost regulator
power is separate, allowing operation with separate bias and power input voltages for improved efficiency or operation
from a single input power source for simplicity. Full power is available for power (PWR) input voltage greater than
6.5V.
Atmel LED Driver-MSLB9061
LED Driver Module
Compact, 6-channel LED Driver Board with I2C Interface
8 Atmel LED Driver-MSLB9061
Single Input Voltage Configuration
The MSLB9061 board can be powered from a single
input voltage source. The configuration depends on the
input voltage range. The three available configurations
are:
•Input voltage between 5.5V and 28V. Apply the
input voltage to the PWR and HVBIAS inputs,
J2 pins 1, 2, and 3, simultaneously. Leave BIAS
and DOUBLE, J2 pins 4 and 5, unconnected. Full
power is available in this configuration with an
input voltage greater than 6.5V.
•Input voltage between 4.5V and 6V. Apply the
input voltage to the PWR, HVBIAS, and BIAS
inputs, J2 pins 1, 2, 3, and 4, simultaneously.
Leave DOUBLE, J2 pin 5, unconnected. Full
power is not available in this configuration.
•Input voltage between 3.1V and 3.6V. Apply the
input voltage to the PWR and DOUBLE inputs, J2
pins 1, 2, and 5. Connect the BIAS and HVBIAS
inputs, J2 pins 3 and 4, together, but do not
apply voltage. Full power is not available in this
configuration.
Separate Power and Bias Input Configuration
The MSLB9061 board can be powered from separate
power and bias input voltage sources. With input
bias voltage below the input power voltage, power
dissipation is reduced for improved power efficiency. In
all cases, apply the power input voltage to the PWR
inputs, J2 pins 1 and 2. Full output power is available for
an input voltage greater than 6.5V. The three available
bias configurations are:
•5.5V to 28V bias input voltage. Connect the bias
voltage to the HVBIAS input, J2 pin 3. Leave
BIAS and DOUBLE inputs, J2 pins 4 and 5,
unconnected.
•4.5V to 6V bias input voltage. Connect the bias
voltage to the HVBIAS and BIAS inputs, J2 pins 3
and 4, simultaneously. Leave DOUBLE, J2 pin 5,
unconnected.
•3.1V to 3.6V bias input voltage. Connect the
bias voltage to DOUBLE, J2 pin 5. Connect
the HVBIAS and BIAS inputs, J2 pins 3 and 4,
together, but do not apply voltage.
I2C Serial Interface
The MSLB9061 driver board uses an I2C/SMBus serial
interface for digital LED control and fault detection.
Four slave ID addresses are available, and are selected
by the I2C address selection switch. The addresses are
shown in Table 4.
9Atmel LED Driver-MSLB9061
Table 4: I2C Slave Address Switch (S1) Settings
ADDRESS SWITCH S1
POSITION I²C SLAVE ADDRESS ADDRESS SWITCH S1
POSITION I²C SLAVE ADDRESS
Position 1
1100_000 (binary)
Position 3
1100_010 (binary)
Position 2
1100_011 (binary)
Position 4
1100_001 (binary)
There are a number of features available through the I2C serial interface. Table 5 shows the registers for the MSL1061
LED driver.
Atmel LED Driver-MSLB9061
LED Driver Module
Compact, 6-channel LED Driver Board with I2C Interface
10 Atmel LED Driver-MSLB9061
Table 5. Atmel LED Driver-MSL1061 Register Map
REGISTER
NAME ADDRESS BIT DESCRIPTION
D7 D6 D5 D4 D3 D2 D1 D0
MSTRCNTRL 0x00 - - - - - - - SLEEP Sleep enable
CNTRL 0x01 - - - - INTPWM EXTCLK TOEN FLTEN
Internal/external generated
PWM, internal/external
clock, I2C timeout and fault
pin enable.
STATUS 0x03 - OTDET SCDET OCDET - - - FLTDET Open/short detect, over-
temperature detect.
OCSTATUS 0x04 - - OC6 OC5 OC4 OC3 OC2 OC1 LED open circuit detected
on STR6 – STR1
SCSTATUS 0x05 - - SC6 SC5 SC4 SC3 SC1 SC0 LED short circuit to VOUT
detected on STR6 – STR1
PWMFREQ 0x06 D7 D6 D5 D4 D3 D2 D1 D0 Internal PWM frequency
(prescaler) generator
PWMDUTY 0x07 D7 D6 D5 D4 D3 D2 D1 D0 Internal PWM duty cycle
generator
STREN 0x09 - - STR6EN STR5EN STR4EN STR3EN STR2EN STR1EN String enable, shutdown
control
IDAC 0x10 - - - - DAC3 DAC2 DAC1 DAC0 4-bit current DAC
For detailed descriptions of the Atmel LED Driver-MSL1061 register-controlled operating modes, see the Atmel LED Driver-MSL1061
Datasheet.
11Atmel LED Driver-MSLB9061
On/Off (EN) Control Input
The on/off control Input, pin 9 of input connector J2, turns on/off the LED driver. Drive it high (between 2.3 and 5V)
to turn on the LED driver, and drive it low (0 to 0.8V) to turn it off. The on/off control input is internally pulled up by a
100kΩ resistor. For automatic start-up, leave it unconnected.
PWM Control Input
The input connector, J2, pin 10, is the PWM control input. Drive PWM with a digital signal to pulse-width modulate
(PWM) the LED brightness. When using the internal PWM generator, the PWM input signal is ignored. The PWM
input is pulled high through a 100kΩ resistor. If not used, leave PWM unconnected or drive it high.
Fault Indicator Output
The MSL1061 includes fault detection circuitry that detects an open-circuited LED string or an LED string with one or
more short-circuited LEDs. If any fault is detected, the fault indicator output is driven low. Use this output as an alert
signal to a system controller. Once the controller gets the alert signal, it determines which LED is faulty by reading the
STATUS, OCSTATUS, and SCSTATUS registers through the I2C serial interface.
Connecting the LEDs to the Atmel LED Driver-MSLB9061 LED Driver
The MSLB9061 driver board drives LED arrays with up to six parallel strings of up to 12 series LEDs each through the
output connector, J3. Six connections for LED cathode connections allow the use of separate LED strings, or common-
anode-connected LED strings. Connect unused LED cathode string connections (J3 pins 9-14) to GND to disable that
LED string. J3 pins 1-8 are provided for this purpose so that unused string cathode connections are connected to GND
through the wiring harness.
Setting the Full-Scale LED Current
The MSL1061 regulates the LED string current. The LED string current is set by a current sense resistor. Four different
values are programmed to the MSLB9061 LED driver module, and the switch S2 selects one of those resistors to set the
full-scale per-string LED current to 10mA, 15mA, 25mA or 30mA. Table 6 shows the switch settings and the full-scale
per-string LED current for each setting.
Atmel LED Driver-MSLB9061
LED Driver Module
Compact, 6-channel LED Driver Board with I2C Interface
12 Atmel LED Driver-MSLB9061
Table 6: Full-Scale Per-String LED Current (S2) Settings
Full-Scale LED Current Switch
S2 Position
Full-Scale Per-String
LED Current
Full-Scale LED Current Switch
S2 Position
Full-Scale Per-String
LED Current
Position 1
30mA
Position 3
15mA
Position 2
25mA
Position 4
10mA
Driving LEDs with Greater than 30mA LED Current
The maximum current available from each LED driver is 30mA. When using LEDs that require greater than 30mA,
connect multiple LED drivers in parallel to drive a single LED string. The LED string current is the sum of the LED driver
currents. Table 7 shows a list of the higher currents that can be supported by this board.
Table 7. Settings for Higher Currents
Current # of Strings EVU-MSL1061
40mA 2 2 x 20mA x 2 strings
3 2 x 20mA x 3 strings
50mA 2 2 x 25mA x 2 strings
3 2 x 25mA x 3 strings
60mA 2 2 x 30mA x 2 strings
3 2 x 30mA x 3 strings
13Atmel LED Driver-MSLB9061
Atmel LED Driver-MSLB9061 Schematic
Figure 2: Atmel LED Driver-MSLB9061 Board Schematic.
Do Not Stuff
Atmel LED Driver-MSLB9061
LED Driver Module
Compact, 6-channel LED Driver Board with I2C Interface
14 Atmel LED Driver-MSLB9061
Atmel LED Driver-MSLB9061 Component Placement
15Atmel LED Driver-MSLB9061
Atmel LED Driver-MSLB9061 Bill of Materials
REF QTY DESCRIPTION MANUFACTURER MANUFACTURER P/N
C1, C2,
C14 3 Capacitor, ceramic, 1µF, 50V, X7R, 1206 Murata GRM31CR71H105KA61L or equivalent
C5,
C13* 2 Capacitor, ceramic, 10µF, 6.3V, X7R, 0805 Murata GRM21BR70J206KE76L or equivalent
C6, C7 2 Capacitor, ceramic, 1µF, 10V, X7R, 0603 Murata GRM188R7A105KA61D or equivalent
C11,
C15 2 Capacitor, ceramic, 0.1µF, 50V, X7R, 0603 Murata GRM188R71H104KA93D or equivalent
C12* 1 Capacitor, ceramic, 2.2µF, 10V, X7R, 0603 Murata GRM188R71A225KE15D or equivalent
D1 1 Rectier, Schottky, 1A, 40V, Power-Di 123 Diodes Inc. DFLS140L-7 or equivalent
J3 1 Connector, 12-position, 1.0mm spacing, low prole JST SM12B-SRSS-TB
J3 1 Connector, 20-position, 1.0mm spacing, low prole JST SM20B-SRSS-TB
L1 1 Inductor, 15µH, 1.4A, CDRH5D28R/HP Sumida CDRH5D28R/HP-150 or equivalent
R1 1 Resistor, 66.5KΩ, 1%, 0603 Rohm MCR03EZPFX6652 or equivalent
R2 1 Resistor, 115KΩ, 1%, 0603 Rohm MCR03EZPFX1153 or equivalent
R5 1 Resistor, 1.00MΩ, 1%, 0603 Rohm MCR03EZPFX1004 or equivalent
R6 1 Resistor, 28.7KΩ, 1%, 0603 Rohm MCR03EZPFX2872 or equivalent
R7, R13 2 Resistor, 100KΩ, 1%, 0603 Rohm MCR03EZPFX1003 or equivalent
R8 1 Resistor, 80.6KΩ, 1%, 0603 Rohm MCR03EZPFX8062 or equivalent
R9 1 Resistor, 133KΩ, 1%, 0603 Rohm MCR03EZPFX1333 or equivalent
R10 1 Resistor, 200KΩ, 1%, 0603 Rohm MCR03EZPFX2003 or equivalent
SW1,
SW2 2 Switch, 4-position, rotary, surface mount, 4.5x5mm Copal Electronics CS-4-14NTA or equivalent
U1 1 LED driver with boost, six-channel, QFN55-28 MSL1061
U2* 1 Doubling charge pump, SOT-23-6 Semtech SC1462ISKTR or equivalent
* Foot print are available for optional use. Do not stuff.
Atmel LED Driver-MSLB9061
LED Driver Module
Compact, 6-channel LED Driver Board with I2C Interface
Atmel Corporation
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San Jose, CA 95131
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Tel: (+1)(408) 441-0311
Fax: (+1)(408) 487-2600
www.atmel.com
© 2011 Atmel Corporation. All rights reserved. / Rev.: MEM-MSLB9061DS1-E-US_06-11
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