Atmel LED Drivers MSL2010 Single String Linear constant current LED Controller with Integrated DC/DC Boost Controller Features Integrated Boost Controller Drives external N-Ch MOSFETS Over-Temperature Fault Detection 8-bit DAC for peak current control PWM Input for Dimming Duty Cycle Linear current control for ripple-free LED current regulation 8-bit Efficiency Optimizer Minimizes Power Use ± 3% Current Accuracy I2C Serial Interface (use Optional) 32 Bytes Free RAM, 32 Bytes Free EEPROM
1. Introduction The MSL2010 LED string driver features a constant off-time Boost Controller and provides very accurate, no ripple, linear controlled string current. The Atmel patent-pending Efficiency Optimizer (EO) controls the switch-mode converter output, optimizing the output voltage to achieve maximum power efficiency.
4. Absolute Maximum Ratings Voltage with respect to AGND AVIN, PVIN, EN VCC, PWM, FLTB, SDA, SCL, TOFF, REXT, FBO VDD CS, S D G, DRV PGND, AGND -0.3V to +16.5V -0.3V to +5.5V -0.3V to +2.75V -0.3V to VDD+0.3V -0.3V to +22V -0.3V to VIN+0.3V -0.3V to +0.
5. Electrical Characteristics AVIN = PVIN = 12V, -40°C ≤TA ≤ 105°C, Typical Operating Circuit, unless otherwise noted. Typical values at TA = +25°C. Table 5-1.
Table 5-2. AC electrical characteristics Parameter Conditions DRV tOFF timing RTOFF = 46.5k PWM Input Frequency (1) Min. Table 5-3. Unit s 60 10,000 Hz 1 100 % PWM Duty Cycle Resolution 1. Max. 0.5 PWM Duty Cycle Note: Typ. 0.4 % 2µs minimum on time, 0% duty cycle is supported. PWM between 0% and 1% not guaranteed I2C switching characteristics Parameter Symbol SCL Clock Frequency STOP to START Condition Bus Free Time Conditions Min. (1) 0.05 Typ. Max.
. Typical Operating Characteristics Figure 6-1. Istr (String Current) rising. Figure 6-2. Istr falling.
Figure 6-3. Start-up behavior, PWM = 10% duty cycle (Test conditions). Figure 6-4. Start-up behavior, PWM = 10% (Zoom) duty cycle (Test conditions).
Figure 6-5. Start-up behavior, PWM = 90% duty cycle (Test conditions). Figure 6-6. Start-up behavior,, PWM = 90%(zoom) duty cycle (Test conditions).
Figure 6-7. Operating current vs. input voltage 100 EN=1 Current (mA) 10 EN=0 1 0.1 0.01 0.001 9.0 10.0 11.0 12.0 13.0 14.0 15.0 16.0 17.0 Vin(V) Figure 6-8. VCC and VDD regulation 6 VCC (V) Voltage (V) 5 VDD (V) 4 3 2 1 0 0.0 10.0 20.0 30.0 40.0 50.0 60.0 70.0 80.0 90.0 100.
Figure 6-9. Efficiency vs DAC value 100.00 % 90.00 % 80.00 % Efficiency 70.00 % 60.00 % 50.00 % 40.00 % 30.00 % 20.00 % 10.00 % 0.
7. Block Diagram Figure 7-1. MSL2010 block diagram VCC VDD D VCC=5V AVIN EFFICIENCY OPTIMIZER REGULATORS VDD=2.5V VREF1 8-BIT CURRENT DAC FBO VDD VREF2 G DAC VREF4 MSL2010 CONTROL LOGIC EN S OSCILLATOR START CLOCK MUX PWM TOFF PVIN CURRENT GENERATOR S Q DRV R QB CS CURRENT GENERATOR EAO VREF3 COFF EA FB VREF5 1.
8.2 AVIN D G Pinout MSL2010 VCC 8.1 AGND Pinout and Pin Description VDD 8. 24 23 22 21 20 19 17 NC PWM 3 MSL2010 16 PVIN SCL 4 (TOP VIEW) 15 DRV SDA 5 14 PGND FLTB 6 13 CS 7 8 9 10 11 12 FB 2 EAO EN TOFF S REXT 18 CGND 1 NC FBO Pin Descriptions Name Pin Description FBO 1 Feedback Output Feedback output from Efficiency Optimizer. Connect FBO to the LED power supply regulation feedback node to control VLED. When unused connect FBO to VCC.
Name Pin CGND 8 REXT 9 External Resistor Connect a 46.4k, 1% resistor from REXT to AGND. 10 Off-Time Set Input A resistor from TOFF to AGND controls the constant off time for the Boost converter, where RTOFF = tOFF (90.9 x 109), with tOFF in seconds and RTOFF in Ohms. For example, an off time of 4.4s TOFF Description Connect to Ground Connect CGND to AGND results in a resistor value of 402k (to the nearest 1% value).
9. Typical Application Circuit MSL2010 Boost Switcher and Linear Driver, Driving 10 White LEDs. Figure 9-1. Typical application circuit 330μH FDD3860 1μF 10 WHITE LEDS LTST-C190EKT 270μF 47kΩ 220pF 0.05Ω 30kΩ 4.7kΩ 0.1μF CS DRV EAO FBO FB 100kΩ PWM D PWM IRFR110 EN PVIN AVIN + 12V - 1uF G S MSL2010 LED DRIVER 1Ω 46.4k 10uF REXT TOFF VCC VDD PGND AGND 24.9k SDA SCL 10uF CONFIGURATION INTERFACE (OPTIONAL) 10.
12.2 The Boost Regulator MSL2010 includes a Constant Off-Time DC/DC Boost Controller to generate VLED, the voltage for the LED string. The Boost components are shown in Figure 12-1 on page 15, and include a voltage setting resistor divider, a MOSFET, a Schottky diode, a resistor to set the Off-Time, an Inductor, a current sense resistor, a Drain resistor, a few capacitors and a compensation network. The following sections discuss selecting these components. Figure 12-1.
where 2.5V is VFB, the feedback regulation voltage of the FB input. The Efficiency Optimizer (EO) output, FBO, connects to FB and pulls current from the node to force the converter’s output voltage up to the proper level to keep the LEDs in current regulation with the minimum power loss. 12.2.2 The Boost MOSFET and Schottky Diode Output DRV drives the gate of an external N-Channel MOSFET at up to VPVIN – 1.5V.
Assure that the inductor saturation current rating is greater than IL, the peak inductor current from the RCS equation above. 12.2.6 The Drain Resistor, RD The drain resistor, RD in Figure 12-1 on page 15, connects the MSL2010 to the Drain of the LED string external MOSFET. Use a 100k for RD. 12.2.7 The Input and Output Capacitors The input and output capacitors carry the high frequency current of the Boost regulator switching.
13. Control Registers Table 13-1. MSL2010 Register Map (Do not change unspecified registers or bits).
Wait 5ms 0x61 00 E2CTRL provides additional functions beyond simply programming a register’s value into the EEPROM. Data may be transferred in either direction, from the registers to the EEPROM, or from the EEPROM to the registers. Register data may be transferred into or out of the EEPROM in groups of eight, a page at a time. The page address boundaries are predefined, and E2ADDR must be loaded with the address of the first byte of the page that is to be copied.
14. Detailed Register Descriptions The MSL2010 registers are summarized in “Control Registers” on page 18. Detailed register information follows. 14.1 RAM (0x00 through 0x1F) 32 Bytes of RAM accessible through the I2C serial interface. Copy data from RAM into EEPROM (see “EEPROM and Power-Up Defaults” on page 18) to have the data automatically load into the RAM at power up, and when EN is taken high. Table 14-1.
14.4 Efficiency Optimizer Control Register (EOCTRL, 0x40) DThresh sets the voltage feedback threshold for D, The LED string MOSFET drain connection. D Threshold = ( 150mV) + 250mV. This is how the device monitors VLED to control the magnitude of the EO current. The default value for DThresh is 1V. Table 14-4.
Figure 15-2. I2C Serial Interface Timing Details SDA tBUF tSU:DAT tSU:STA tHD:STA tHD:DAT tSU:STO tLOW SCL tHIGH tHD:STA tR tF START CONDITION 15.1 REPEATED START CONDITION START STOP CONDITION CONDITION I2C Bus Timeout The bus timeout feature allows the MSL2010 to reset the serial bus interface if a communication ceases before a STOP condition is sent.
15.4 I2C Acknowledge Bit The acknowledge bit is a clocked 9th bit which the recipient uses to handshake receipt of each byte of data. The master generates the 9th clock pulse, and the recipient holds SDA low during the high period of the clock pulse. When the master is transmitting to the MSL2010, the MSL2010 pulls SDA low because the MSL2010 is the recipient. When the MSL2010 is transmitting to the master, the master pulls SDA low because the master is the recipient. Figure 15-5.
Figure 15-7. I2C Writing a Register Pointer ACKNOWLEDGE FROM MSL2010 START SDA 0 1 0 0 0 0 0 0 A ACKNOWLEDGE STOP FROM MSL2010 . D7 . SLAVE ADDRESS, WRITE ACCESS . . . . D0 A SET REGISTER POINTER TO X THE REGISTER POINTER NOW POINTS TO X; A SUBSEQUENT READ ACCESS READS FROM REGISTER ADDRESS X When no STOP condition is detected, the byte transmitted after the register address byte is a data byte, and is placed into the register pointed to by the register address byte (Figure 15-8).
followed by a stop condition. This technique is recommended for buses with multiple masters, because the read sequence is performed in one uninterruptible transaction. Figure 15-10. I2C Reading Register Data Using a Repeated START ACKNOWLEDGE FROM MSL2010 START SDA 0 1 0 0 0 0 0 0 A D7 ACKNOWLEDGE FROM MSL2010 . . SLAVE ADDRESS WRITE ACCESS 15.8 . . . . REPEATED START D0 A 1 ACKNOWLEDGE FROM MSL2010 0 SET REGISTER POINTER 1 0 0 0 0 1 A NOT ACKNOWLEDGE STOP FROM MASTER .
d 0.1 C Packaging Information d 0.1 C (TOP VIEW) D 24 (SIDE VIEW) d 0.08 SEATING PLANE d 0.1 C 1 2 PIN 1 ID E A A1 (A3) D2 e/2 E2 COMMON DIMENSIONS (UNIT OF MEASURE=MM) e SYMBOL 24X L 24X b K 16. (BOTTOM VIEW) MIN NOM MAX A - 0.85 0.90 A1 0.00 - 0.05 0.203 REF A3 b 0.20 D D2 NOTES: 2. Dimension "b" applies to metalized terminal and is measured between 0.15mm and 0.30mm from the terminal tip.
17. Datasheet Revision History 17.1 42072A – 05/2013 1. Initial revision.
Table of Contents 1. Introduction 2 2. Ordering Information 2 3. Application Circuit 2 4. Absolute Maximum Ratings 3 5. Electrical Characteristics 4 6. Typical Operating Characteristics 6 7. Block Diagram 11 8. Pinout and Pin Description 12 8.1 8.2 Pinout MSL2010 12 Pin Descriptions 12 9. Typical Application Circuit 14 10. Detailed Description 14 11. Fault Conditions 14 12. Applications Information 14 12.1 12.2 12.3 Turn-On Sequence 14 The Boost Regulator 15 The LED string 17 13.
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