Auto Electronics

LED driver eliminates external MCU or switch-mode converter

Targeting automotive interior and exterior lighting, among other applications, Maxim Integrated Products has introduced the MAX16806, an EEPROM-programmable, 350 mA, high-voltage (40 V) linear, high-brightness LED driver.

The MAX16806 requires minimum external components to implement the LED driver circuit in automotive dome and map-lighting applications. It can be programmed through an I2C interface to fold back the LED current if input voltage or LED temperature rises above the programmed threshold. It thus reduces cost and EMI concerns by eliminating the need for a switch-mode converter, which is normally needed to reduce power dissipation.

As automakers replace incandescent lamps with white LEDs for dome and map lights, the LEDs must work with existing control modules; however, theater dimming signals operate at very low frequencies and can cause LEDs to blink noticeably during dimming. To eliminate this effect, LED drivers typically require a microcontroller to create a new PWM signal. A 200 Hz on-board ramp in the MAX16806 allows analog control of PWM dimming and eliminates the need for an MCU-generated PWM signal.

Maxim’s new LED driver uses an EEPROM-programmable current-sense reference to ensure consistent brightness. The reference eliminates the need for a matrix of sense resistors to match each LED bin in production. LED current can be programmed during production, based on LED bin information, using just one of the sense resistor's values and the I2C interface.

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