SLUSAR9D December 2011 – December 2021 TPS28225-Q1
PRODUCTION DATA
The bootstrap diode provides the supply voltage for the UGATE driver by charging the bootstrap capacitor connected between BOOT and PHASE pins from the input voltage VDD when the low-side FET is in ON state. At the very initial stage when both power FETs are OFF, the bootstrap capacitor is precharged through this path including the PHASE pin, output inductor and large output capacitor down to GND. The forward voltage drop across the diode is only 1.0 V at bias current 100 mA. This allows quick charge restore of the bootstrap capacitor during the high-frequency operation.