SNVSB97A December 2018 – September 2021 LM34936-Q1
The LM34936-Q1 provides four N-channel MOSFET gate drivers: two floating high-side gate drivers at the HDRV1 and HDRV2 pins, and two ground referenced low-side drivers at the LDRV1 and LDRV2 pins. Each driver is capable of sourcing 1.8 A and sinking 2.2-A peak current. In buck operation, LDRV1 and HDRV1 are switched by the PWM controller while HDRV2 remains continuously on. In boost operation, LDRV2 and HDRV2 are switched while HDRV1 remains continuously on.
The low-side gate drivers are powered from VCC and the high-side gate drivers HDRV1 and HDRV2 are powered from bootstrap capacitors CBOOT1 (between BOOT1 and SW1) and CBOOT2 (between BOOT2 and SW2), respectively. The CBOOT1 and CBOOT2 capacitors are charged through external Schottky diodes connected to the VCC pin as shown in Figure 8-1.
In most applications, ceramic capacitors of 16-V or higher voltage rating and values between 0.1 µF and 0.22 µF are sufficient for CBOOT1 and CBOOT2.