The boost controller section in each L99LD21 LED driver integrates a high current gate driver for an external N-channel MOSFET and delivers a constant output voltage to two integrated buck converters. The boost controller of two devices can be stacked to allow dual phase operation for high power applications, with an interleaving pattern for improved input current ripple and current load sharing. The buck converter integrates an N-channel MOSFET driven by a bootstrap circuit.
The board uses SPI communication with an external microcontroller via a 12-pin male connector, and a special Limp Home Mode implemented in the L99LD21 driver ensures that active communication with the MCU is regularly monitored. You can use the AutoDevKit library extension for the SPC5-Studio development environment to install board firmware drivers that are immediately compatible with SPC5-family MCUs.
The overall package is designed to address automotive lighting applications, including high beams and low beams, daytime running lights, turn indicators, position lights, side markers and fog lights.