Synchronous buck LED driver for headlights and adaptive LED modules

23-07-2020 | Texas Instruments | Automotive & Transport

The TPS92520-Q1 Synchronous Buck LED Driver is a monolithic dual synchronous buck LED driver from Texas Instruments. The device provides a wide 4.5V to 65V operating input voltage range that is able to independently power two strings of series connected LEDs. The device achieves an adaptive on-time average current mode control and is created to be compatible with shunt FET dimming techniques and LED matrix manager-based dynamic beam headlamps. The adaptive on-time control offers near constant switching frequency that is able to be set between 100kHz and 2.2MHz. The device inductor current sensing and closed-loop feedback allow better than ±4% accuracy over the wide input voltage, output voltage and ambient temperature range.

The high-performance LED driver can independently modulate LED current utilising both analog or PWM dimming techniques. Linear analog dimming response with over 16:1 range is achieved by programming the 10-bit IADJ value via SPI. PWM dimming of LED current is performed by directly modulating the corresponding UDIM input pin with the wanted duty cycle or by allowing the internal PWM generator circuit. The PWM generator translates the 10-bit PWM register value to a corresponding duty cycle by comparing it to a programmable digital counter.

The device includes advanced SPI programmable diagnostic and fault protection featuring cycle-by-cycle switch current limit, bootstrap undervoltage, LED short, LED open, thermal warning and thermal shutdown. The on-board 10-bit ADC samples critical input parameters needed for system health monitoring and diagnostics.

The device is provided in an 8.1mm x 11mm thermally-enhanced 32-pin HTSSOP package with a 2.75mm x 3.45mm top-exposed and bottom-exposed pad. The device is created for automotive headlights and adaptive LED driving modules.

By Natasha Shek