Bootstrap circuit for high side MOSFET driving

This is a bootstrap circuit  for driving a high side MOSFET. How to use this? There are two signal lines. Connect the top signal to  ground to switch the MOSFET on. Connect the other signal to  ground to switch the MOSFET off. Never drive both signals at the  same time, that would cause a short. Converting a PWM signal into those  two signals is not impossible,   but would require another handful of transistors. It uses one capacitor, one diode,  two transistors and tree resistors. The capacitor has its negative side  connected to the source of the MOSFET. A PNP transistor connects the  capacitor to the gate to turn it on. Another PNP transistor connects the  gate to the source to turn it off. When the MOSFET is off, source is equal to ground  and the capacitor gets charged through the diode. The two 10 kilo ohm resistors are there to  limit the current flow through the resistors.   The faster the switching, the lower  value the resistors should be. The 1 mega ohm resistor is a  pull-up resistor for the base   of the "turn on" transistor.  This prevents some problems. The advantages of this circuit are: Fast switching High side switching Cheap components The disadvantages are: It can't use PWM signal MOSFET can't stay on forever

Channel: krakkus

Views: 2,950

Keywords: diy mosfet driver

Id: 3CVWY0Ty2QI

Length: 1min 32sec (92 seconds)

Published: Sat Feb 18 2023