Mosfet in Bq20z95

Deepak Bansal

I have started working on Bq20z95 & noticed that it has N- channel CHg & DCHG Fet on high side. Usually it is preferred to use P-channel to use on high side.

I think by using n-channel fet on high side, we have to buffer voltage on Gate pin (i.e greater voltage on gate then on drain pin). Please correct me if I am wrong.

Is there is any advantage or specific reason of using n-channel fet on high side?

over 13 years ago

0 Chase7071949597 over 13 years ago

TI__Genius 10235 points

The z95 uses charge pumps for FET control, so no buffer voltage is required. The charge pumps ensure that the gate voltage is approximately double the source when the FET drive is on.

0 Deepak Bansal over 13 years ago in reply to Chase7071949597

Expert 2395 points

Many thanks for your reply. Kindly help in below issues:

1. Usually, P channel fet is preferred on high side. Is there any advantage of using N -channel in this circuit.

2. I noted the voltage across gate terminal. It usually remains at around 20V.

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Mosfet in Bq20z95