imulate a small Voltage Drop Out with MOSFET vs. parasitic capacitances

Hello,

i want to simulate a small voltage drop out (variable between 1us to 40us), the supply voltage is also variable (between +5V to +35V).

On the basis of the facts that a relay is to slow i think about a MOSFET, it should withstand high voltage and high current.

The problem i have is that to switch in MHz-range i need high current so that the MOSFET parasitic capacitances are reloaded and the waveform of switching have a rectangle signale form.

Does anybody know a solution to eliminate parasitic capacitances ?

I don't think the MOSFET would be the problem, many MOSFETs can switch in the MHz range (you didn't specify what frequency). The problem is what it is driving. The capacitance on the drive side will drastically effect the signal, because as we all know, you can't instantaneously change the voltage on a capacitor. What are you driving? What are its characteristic capacitance and inductance values???

my switching frequency is between 25kHz (1/40us) up to 1MHz (1/1us).

I want to drive a pump, motor applikation so i have to provide min. 2A, but i don't know the capacitance and inductance valuesat time

Why do you want to do that?

Are you talking about PWM? Normally a lower frequency is used for that.

no pwm, i want to simulate a short break down of the power supply voltage

dirkdiggler2oo2 said:

no pwm, i want to simulate a short break down of the power supply voltage

Click to expand...

It is unlikely that a power supply would drop out with a sharp drop like that. The filtering caps in a supply would prevent that from happening. Can you elaborate on what type of fault would drop the supply like that?

A fault on the circuit side, or wireing fault coming from the power supply. Just off the top of my head (not the original poster)