ANALOG DEVICES EVAL-LT3964-1-AZ Synchronous Dual LED Driver User Guide

Evaluation Board User Guide
EVAL-LT3964-1-AZ
36V Synchronous Dual LED Driver with I2C

General Description

The EVAL-LT3964-1-AZ evaluation circuit is a 36V synchronous dual Light- emitting diode (LED) driver with I2C featuring the LT® 3964-1. It drives two channels of LEDs at 1A when V IN is between 9V and 36V. EVALLT3964-1-AZ runs at 2MHz switching frequency. Its two channels can drive separate LED strings, which can have different currents, voltages, or dimming ratios. It can be controlled with I2C communications, or it can be run in nonI2 C mode with proper ADDR pin settings. It is protected against both open and short LED conditions and reports the faults. In I2C mode, faults can be enabled or disabled. Up to 8 different EVAL-LT3964-1-AZ can be placed on the same I2 C bus with unique addresses. A serial interface is available when connected to a DC2026C Linduino® One demo circuit.
The LT3964-1 has an input voltage range from 4V to 36V. It has two independent 1.8A, 40V bucks with internal, synchronous 40V switches for high efficiency and small size. It has an adjustable switching frequency between 200kHz and 2MHz. It can be synchronized to an external source or programmed with a clock output (CLKOUT). The PWMTG high-side PWM MOSFET drivers assist with short- circuit protection and versatility. Although the evaluation circuit is optimized for just two LEDs per channel, it can be altered to be buck regulators with as high as 33V of LEDs if V IN is high enough and circuit components are changed appropriately.
In non-I2C mode, each channel can separately be PWM- and analog-dimmed by placing a PWM signal or CTRL voltage on the provided turrets. In I2C mode, each channel can be dimmed to up to 8192:1, and analog dimmed to a high ratio using serial communications.
Small ceramic input and output capacitors are used to save space and cost. The open LED overvoltage protection uses the IC’s constant voltage regulation loop to regulate the output to approximately 8.1V if the LED string is opened.
Undervoltage lockout can be adjusted on the circuit with a few simple resistor choices. The output voltage (overvoltage protection) can be adjusted by changing the feedback resistors for higher string voltages. Other components may also need to be changed to accommodate higher voltages.
The LT3964-1 data sheet gives a complete description of the device, operation, and applications information. The data sheet must be read in conjunction with this user guide for EVAL-LT3964-1-AZ. The LT3964RUHE-1#PBF is assembled in a 36-lead plastic 5mm × 6mm QFN package with a thermally enhanced ground pad. A proper board layout is essential for maximum thermal performance. Refer to the datasheet Layout Considerations section.

Design files for this circuit board are available at https://www.analog.com.

Performance Summary (TA = 25°C)

Quick Start Procedure

How to Operate in Non-I2C Mode
The EVAL-LT3964-1-AZ is easy to set up to evaluate the performance of the LT3964-1 in non-I2C mode. Follow the procedure below:

1. With power off, connect a string of LEDs between LED1+ and LED1– terminals and the same for LED2+ and LED2–. Connect the EN/UVLO terminal to GND to keep the circuit shut down. With power off, connect the input power supply to the PVIN and GND terminals. Make sure that the input voltage does not exceed 36V.
2. For non-I2C mode operation, set both JP1 and JP2 (ADDR1 and ADDR2) to 0. The 00 address pins setting is for non-I2 C mode, but all other settings are for I 2C serial communication mode.
3. Turn the input power supply on and make sure the voltage is between 11V and 36V to start the operation.
4. Release the EN/UVLO-to-GND connection.
5. Observe the LED string running at the programmed LED current.
6. To change the brightness with analog dimming in non-I2 C mode, simply attach a voltage source to the CTRL1 and/or CTRL2 terminals and set the voltage between 0V and 1.5V. See datasheet for details.
7. To change the brightness with external PWM dimming in non-I2 C mode, simply attach a rectangular waveform with varying duty cycles to the PWM1 and/or PWM2 terminals.

How to Operate with Serial Interface – I2C Serial Communication Mode

1. With power off, connect a string of LEDs between LED1+ and LED1– terminals and the same for LED2+ and LED2–.
   Connect the EN/UVLO terminal to GND to keep the circuit shut down. With power off, connect the input power supply to the PVIN and GND terminals. Make sure that the input voltage does not exceed 36V.

2. For I2 C serial communication operation, set JP1 (ADDR1) to FLOAT and JP2 (ADDR2) to 0. FLOAT and 0 are the default address settings of the EVAL-LT3964-1-AZ serial interface example code offered by Analog Devices, Inc.
   However, they can be easily adjusted to send to any address. In general, serial communication can be used with the LT3964-1 as long as the ADDR1 and ADDR2 settings are anything other than 00. There are three states to each ADDRX pin, 0, 1, or float. There are eight unique I2C address settings.

3. Connect a ribbon cable between the J1 serial communication connection and a Linduino One (DC2026C) demo circuit.

4. Connect a USB cable between a PC and the DC2026C.

5. Download the latest Linduino Sketchbook, QuikEval Program, and Arduino IDE.

6. Refer to the DC2026C Demo Manual for detailed instructions on installing and configuring the above software.

7. Download the Linduino code and library files, EVAL_LT3964_1_AZ_FIRMWARE.zip, from the EVAL-LT3964-1-AZ web page. Unzip the files and store them in your working directory.

8. Launch Arduino IDE.

9. Open the code, EVAL_LT3964_1_AZ.ino, in Arduino IDE, compile, and upload to the Linduino.

10. Open the serial monitor inside Arduino IDE.

11. Turn the input power supply on between PVIN and GND terminals and make sure the voltage is between 11V and 36V to start operation.

12. Release the EN/UVLO-to-GND connection.

13. Use the command line interface in the serial monitor to evaluate the performance of EVAL-LT3964-1-AZ.

EVAL-LT3964-1-AZ

Table 1. I2 C ADDR Jumpers (JP1 and JP2) Setting

*Default position

Performance

Bill of Materials

ITEM| QTY| DESIGNATOR| DESCRIPTION| MANUFACTURER PART NUMBER
---|---|---|---|---
REQUIRED CIRCUIT COMPONENTS
1| 2| C1,C7| CAP CER 2.2uF 50V 10% X7R 0805| TAIYO YUDEN, UMK212BB7225KG-T
2| 2| C10,C12| CAP CER 2.2uF 10V 10% X5R 0805| TAIYO YUDEN, LMK212BJ225KD-T
3| 2| C9,C11| CAP CER 0.22uF 50V 10% X5R 0402| TAIYO YUDEN, UMK105BJ224KV-F
4| 1| C5| CAP ALUM 33UF 20% 50V 6.6X6.6MM| WURTH, 865080645010
5| 1| C6| CAP CER 2.2UF 25V 10% X5R 0402 AEC-Q200| MURATA, GRT155R61E225KE13D
6| 14| El ,E2,E3,E4,E5,E6′ E7,E8,E9,E10,E11′  E12,E13,E14| CONN-PCB SOLDER TERMINAL TEST POINT TURRET 0.094″ MTG. HOLE PCB 0.062 INCH THK| MILL-MAX, 2501-2-00-80-00-00-07-0
7| 1| J1| CONN-PCB SHROUDED HDR ST 14P MALE| MOLEX, 87831-1420
8| 2| JP1,JP2| CONN-PCB EPOS UNSHROUDED HEADER VERT 2MM PITCH| SAMTEC INC., TMM-103-02-L-D
9| 1| JP3| CONN-PCB SINGLE ROW HDR 2MM PITCH| SAMTEC, TMM-102-01-G-S
10| 2| L1,L2| IND SHIELDED POWER 1.9A 0.1580HM DCR| WURTH, 74438336047
11| 2| M1,M2| TRAN P-CH POWER MOSFET| INFINEON TECHNOLOGIES AG, IRLML6401TRPBF
12| 1| R1| RES SMD 332K Ohm 1% 1/10W 0402 AEC-Q200| PANASONIC, ERJ-2RKF3323X
13| 2| R10,R14| RES SMD 1MEG Ohm 1% 1/10W 0402 AEC-Q200| PANASONIC, ERJ- 2RKF1004X
14| 2| R11,R15| RES SMD 169K Ohm 1% 1/10W 0402 AEC-Q200| PANASONIC, ERJ- 2RKF1693X
15| 2| R12,R16| RES SMD 0.1 Ohm 1% 1/2W 0805 AEC-Q200| SUSUMU, KRL1220E-M-R100-F-T5
16| 1| R2| RES SMD 51.1K Ohm 0.1% 1/16W 0402 AEC-Q200 HIGH RELIABILITY| PANASONIC, ERA-2AEB5112X
17| 5| R3,R4,R5,R26,R27| RES 100K OHM 1% 1/16W 0402| YAGEO, AC0402FR-13100KL
18| 2| R28,R29| RES SMD 0 Ohm JUMPER 1/10W 0402 AEC-Q200| PANASONIC, ERJ- 2GEOROOX
19| 1| R6| RES SMD 165K Ohm 1% 1/16W 0402| YAGEO, RC0402FR-07165KL
20| 1| R7| RES SMD 499K Ohm 1% 1/10W 0402 AEC-Q200| PANASONIC, ERJ-2RKF4993X
21| 1| R8| RES SMD 27.4K Ohm 1% 1/10W 0402 AEC-Q200| PANASONIC, ERJ-2RKF2742X
22| 1| R9| RES SMD 20K Ohm 1% 1/10W 0402 AEC-Q200| PANASONIC, ERJ-2RKF2002X
23| 1| U1| IC-ADI DUAL 36V SYNCHRONOUS 2A BUCK LED DRIVER WITH 12C| ANALOG DEVICES, LT3964RUHE-1#PBF
OPTIONAL CIRCUIT COMPONENTS
1| 5| C2,C8,C13,C18,C19| CAP., OPTION, 0402|
2| 3| C3,C4,C14| CAP., OPTION, 0805|
3| 1| FB1| IND CHIP FERRITE BEAD 1000HM 25% 100MHZ 4A 0.020HM DCR 0805| TDK, MPZ2012S101AT000
4| 2| FB2,FB3| IND CHIP FERRITE BEAD 0805| MURATA, BLM21BD152SN1D
5| 1| L3| IND POWER SHIELDED WIREWOUND 2.2UH 20% 100KHZ 1.3A 0.176 OHM DCR 1008, AEC-Q200| WURTH, 74438323022
6| 6| R13,R17,R21,R22′ R24,R25| RES., OPTION, 0402|
HARDWARE – FOR DEMO BOARD ONLY
1| 2| | SHUNT, 2POS, 2MM PITCH, BLACK| I SAMTEC INC., 2SN-BK-G

Schematic

Revision History

Revision Number| Revision Date| Nature of Change| Page Number
---|---|---|---
Rev 0| 9/23| Initial Release| —

ASSUMED BY ANALOG DEVICES FOR ITS USE, NOR FOR ANY INFRINGEMENTS OF PATENTS OR OTHER RIGHTS OF THIRD PARTIES THAT MAY RESULT FROM ITS USE. SPECIFICATIONS ARE SUBJECT TO CHANGE WITHOUT NOTICE. NO LICENCE, EITHER EXPRESSED OR IMPLIED, IS GRANTED UNDER ANY ADI PATENT RIGHT, COPYRIGHT, MASK WORK RIGHT, OR ANY OTHER ADI INTELLECTUAL PROPERTY RIGHT RELATING TO ANY COMBINATION, MACHINE, OR PROCESS WHICH ADI PRODUCTS ALL INFORMATION CONTAINED HEREIN IS PROVIDED “AS IS” WITHOUT REPRESENTATION OR WARRANTY. NO RESPONSIBILITY IS OR SERVICES ARE USED. TRADEMARKS AND REGISTERED TRADEMARKS ARE THE PROPERTY OF THEIR RESPECTIVE OWNERS.

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References

• Mixed-signal and digital signal processing ICs | Analog Devices
• Document Feedback Form | Analog Devices
• Mixed-signal and digital signal processing ICs | Analog Devices
• Mixed-signal and digital signal processing ICs | Analog Devices
• Mixed-signal and digital signal processing ICs | Analog Devices

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