gate driver circuit for mosfet

[dark night]

hi,
I've designed a boost converter with a 30V input. It is running at 60% duty cycle.

for pwm circuit i have been used pic to generate a pwm.



so my question is (as shown in the circuit) hows the pwm inverted (after gate drive)

any help to understand the operation of the gate drive?

 

[Harald Kapp]

PWM=0V:
Q1 is off
R5 biases Q2 = on, Q3 = off

PWM=3.3V:
Q1 is on
Q2 is off, Q3 is on.

That's not too difficult, is it?

Harald

 

[dark night]

thank you so much
your explanation is easy to understand.

 

[dark night]

hi,

what the function of the diode D1?

any help.

 

[BobK]

It is bypassing the gate resitor during the turn off phase to make it turn off faster.

Bob