Summary of LT3964 – Dual 36V Synchronous 1.6A Buck LED Driver with I2C
The LT3964 is a dual synchronous step-down DC/DC converter designed for driving LEDs with I2C control. It supports wide input voltage (4V to 36V), offers precise constant current regulation, and features extensive dimming capabilities via internal and external PWM or analog signals. The device includes robust protection mechanisms like open LED detection and short-circuit reporting, making it suitable for industrial, medical, and automotive lighting applications.
Parts used in the LT3964 Project:
- Dual Synchronous Step-Down DC/DC Converter
- I2C Interface
- Microcontroller
- External Resistor
- LEDs
- Output Disconnect PMOS Switch Driver
- Clock Output for Frequency Synchronization
- CTRL Pin for Analog Dimming
- FB Pin for Protection Features
- 5mm × 6mm 36-Lead QFN Package
Features
- Wide Input Voltage Range: 4V to 36V
- Two Independent 1.6A/40V Synchronous Bucks
- I2C Interface for Internal True Color PWM™ Dimming (8192:1), Analog Dimming and Fault Reporting
- 1000:1 External True Color PWM Dimming and 10:1 External Analog Dimming
- PMOS Switch Driver for PWM and Output Disconnect
- ±3% Constant Current Regulation
- Adjustable Frequency: 200kHz to 2MHz
- Frequency Synchronization with Clock Output
- Programmable OPENLED Protection with Reporting
- Short-Circuit Protection with Reporting
- Programmable Undervoltage Lockout with Hysteresis
- Internal Compensation
- 9 Unique Device Addresses for I2C
- Available in 5mm × 6mm 36-Lead QFN Package
Typical Application
Description
The LT®3964 is a dual synchronous step-down DC/DC converter with I2C interface designed to operate as a constant-current and constant-voltage source and is ideal for driving LEDs. The fixed frequency and peak current mode topology result in stable operation over a wide range of supply and output voltages. The ground referred voltage FB pin serves as the input for several LED protection features, and also allows the converter to operate as a constant-voltage source. The maximum output current is set by an external resistor, and the output current amplifier has a rail-to-rail common mode range. LT3964 uses an I2C interface to communicate with a microcontroller to read LED faults, write PWM and analog dimming registers and set fault masking. The I2C PWM input provides LED dimming ratios up to 8192:1. The I2C programmable CTRL register sets the gain of the external CTRL pin, and maximum current sense threshold, providing additional analog dimming capability.
Applications
- General Purpose, Industrial, Medical and Automotive Lighting
- Constant-Current, Constant-Voltage Source
Read More: LT3964 – Dual 36V Synchronous 1.6A Buck LED Driver with I2C
- What is the primary function of the LT3964?
The LT3964 is a dual synchronous step-down DC/DC converter designed to operate as a constant-current and constant-voltage source for driving LEDs. - How does the device communicate with a microcontroller?
The LT3964 uses an I2C interface to read LED faults, write PWM and analog dimming registers, and set fault masking. - Can the output current be adjusted?
Yes, the maximum output current is set by an external resistor. - What is the range of the input voltage?
The device supports a wide input voltage range from 4V to 36V. - Does the LT3964 support frequency synchronization?
Yes, it features frequency synchronization with a clock output. - How many unique device addresses are available for I2C?
There are 9 unique device addresses available for I2C communication. - What protection features are included in the device?
The device includes programmable OPENLED protection, short-circuit protection, and programmable undervoltage lockout with hysteresis. - Can the device operate as a constant-voltage source?
Yes, the ground referred voltage FB pin allows the converter to operate as a constant-voltage source.
