I have a square wave signal of 300 KHz which is 0.2 V to 1 V. It is the output of FP5138 Non-Sync PWM Controller IC. I want to drive a PMOS with this square wave but with the levels shifted to (Vin-12)V ... (Vin-5)V to Vin, where Vin is 20 to 32 V.
To explain it better, let me try this way (the Vin above and below are different):
0 1
Vin : A -> B
Vout: C -> D
A: 0.1 V typ, 0.2 V max
B: 1.0 V typ, 1.2 V max
C: D-12 min, D-5 max
D: 20 V min, 32 V max
I have 12V, 1A source (78L12) and Vin source of the converter which has boundaries of D above.
It is going to be a P-MOSFET driver and I need up to 0.3 or maybe 0.4 A spikes for Cgs. MOSFET is not yet chosen.
I have tried to build this circuit but no hope.
I hope I could explain myself.
Answer
You do not need or want the intermediate voltage represented by V3.Trying to create it as an actual volateg will cause you effort which is not required.
Allow the low side driver to drive a high side driver connected to tje V+ rail.
THEN limit the swing of the high side driver OR the swing that the FET gate sees. Zener diodes are your friends in such cases.
Note that you should zener clamp the INPUT of a driver stage, not the output - so that the driver is not always "fighting" the zener. .
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