I have a circuit based on a P-FET which shall limit inrush current (20 mA). However, when turning on the power supply there is always a current peak (30 mA, 5 ms) through the M1. Even if I tie its gate to the source.
My question is: What effect is causing that current peak?
- Is the P-FET initially conducting?
- Is there a capacitance in series with the P-FET which could be large enough to let that current pass?
Appreciate any hints. If there are details missing in my description, my apology in advance.
@WhatRoughBeast I have updated the FET type.
In order to detail my last comment about counteracting the condition which leads to initial FET conduction (capacitive voltage divider) I'd like to draw what I have in mind. Maybe that helps to understand and discuss about.
So theoretically one would need a charge pump in order to cancel the inrush current through Cgs so no significant (less than Vgs_th) Vgs would develop. The charge pump would need to be very fast.
What do you/others think?