Driving high-side N-Chanel mosfet

Question

Some time ago Istarted a quadcopter project but the ESCs appeared to be expensive, so Idecided tu build my ones with components and I'm like facing a problem with mosfets (since I don't wanted to une P-chanel ones) and I Have some questions :

1): I have these buck drivers but I've burnt 2 of them by trying to use them as normal drivers.

I cant buy another ones.

if I could,how ?

2)if not : I have already saw an esc with only n-chanels mosfets with no drivers on it but only components near them ; can I build a bootstrap circuit on my own ?

thx.

nico

dougw · Accepted Answer

You will need an oscillating signal to drive a charge pump....

genebren · Answer

Nicolas, The frequency of the squarewave input into the pump is depends on the value of capacitors (Cpump and Ctank) and the amount of current driving the gate. A typical usage for charge pumps are on RS-232 tranceivers, where they need to generate higher voltage levels for the RS-232 levels. Looking at these parts, a good starting point, using 0.1uF capacitors, would be pump frequency of 500KHz. Gene

dougw · Answer

The bipolar transistors are only needed if you want to switch the main FET quickly.

If there is just a resistor pulling up the gate it will have to charge the gate capacitance causing an RC time delay.

Driving high-side N-Chanel mosfet

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