Automotive-qualified LED driver with adaptive dc-dc controller for maximized efficiency
The STMicroelectronics ALED7709 combines an AEC-Q100 Grade 1-qualified 4-channel LED driver with a dc-dc controller capable of boost and SEPIC operation from an input-voltage range of 4.5 V to 42 V.
The ALED7709 LED drivers from STMicroelectronics can be used to drive strings of high-brightness LEDs in many types of automotive application. Supported by an integrated dc-dc controller, these LED drivers supply an output voltage of up to 42 V at each channel. The output current at each channel is programmable in a range up to 200 mA, and channels can be paralleled for a combined output of up to 800 mA.
Each LED driver offers ±2% output current accuracy with mixed PWM and analog dimming at a frequency between 100 Hz and 12.8 kHz. This gives a wide brightness range: the dimming ratio is 10,000:1 at 100 Hz.
The integrated dc-dc controller can operate in boost, SEPIC, and adaptive modes in order to maximize the efficiency of operation. The switching frequency is adjustable between 250 kHz and 2.2 MHz, with the option of spread-spectrum operation.
The ALED7709 can operate in stand-alone, bus-driven, or simultaneous modes. Two preconfigured ALED7709 versions are available for single-mode operation: the ALED7709A supports use with a microcontroller for bus-driven operation using I2C serial interfaces, and the ALED7709B accepts PWMI control signals for stand-alone operation.
The ALED7709 LED drivers feature over-voltage, over-current, over-temperature, and LED fault detection and protections, with automatic channel disconnect capabilities.