Quantcast
Channel: Active questions tagged transistors - Electrical Engineering Stack Exchange
Viewing all articles
Browse latest Browse all 189

Is Vgs a concern when using a high-side FET driver?

$
0
0

I would like to use the MIC5014 to drive an N-channel MOSFET as a high-side switch. My supply voltage in this system is 24 V. I understand that the MIC5014/MIC5015 uses an internal charge-pump to bring the gate of the power FET above the supply voltage, and that it uses a Zener diode to prevent the charge pump from going more than 15 V over the supply voltage. So ultimately the gate voltage would reach 39 V, but this would not be a concern since voltage relative to the source (Vgs) would only be 15 V.

What I am concerned about is negative Vgs when turning off the MOSFET. If gate of the power FET was pulled down to its source, there would be no concern as Vgs would be zero. But my amateur reading of the MIC5014 block diagram leads me to believe that the power FET gate is pulled all the way down to through a diode. Wouldn't that cause a Vgs of -24 V, exceeding the -20 V minimum Vgs of almost all FETs? If so, what should I do instead?

The block diagram from the datasheet is as follows:

MIC5014/MIC5015 block diagram


Viewing all articles
Browse latest Browse all 189

Latest Images

Trending Articles





Latest Images