EDN's 19th Annual Innovation Awards Finalists

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Category: Power ICs: Drivers
Finalist: MAX16826 four-string LED driver (Maxim Integrated Products)

Designed for flexibility, the MAX16826 is a four-string LED driver for automotive applications that includes a boost converter to bias the LEDs, and four current sinks to control the currents in each string. The driver uses external MOSFETs both for the boost converter function and for the current sinks, thus allowing the driver to handle a broad range of LED current levels. Becasue the heat is dissipated across a larger board area, there is not just one hot-spot to deal with and that improves system reliability.

Additionally, the MAX16826 is the only automotive multi-string LED driver to incorporate an I2C serial port. This port allows the chip to communicate with the host system and allows the host system to control the chip. The MAX16826 protects itself and the system around it in case of LED short or open faults; the I2C interface allows the system to read this fault condition and act accordingly. The port also allows the software setting of LED currents, and the reading of operating voltages and setting the boost output voltage: The software can adjust the boost voltage to optimize efficiency by minimizing the voltage drop on the current-sink MOSFET’s. Voltages are read by an internal ADC. When the LEDs are PWM-dimmed, an innovative circuit samples those voltages during the on time, even if this time is very short (few microseconds).The values are stored during the off time, so that they can be read at any moment.