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Author Topic: How to drive pMOS and nMOS H-bridge?  (Read 1861 times)

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Offline newInRoboticsTopic starter

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How to drive pMOS and nMOS H-bridge?
« on: November 06, 2011, 11:48:21 AM »
Hi everyone,

I'm a bit confused on how to drive H-bridge consisting of pMOSFETS and nMOSFETS with single signal pin.

When swith breaks the circuit, pull-up resistor of pMOS_1 turns pMOS OFF, however, nMOS_2 stays ON because of voltage created by pMOS and nMOS resistors voltage divider. What should I use in order to drive such half bridge?
« Last Edit: November 07, 2011, 01:43:33 AM by newInRobotics »
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Offline newInRoboticsTopic starter

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Re: How to drive pMOS and nMOS H-bridge?
« Reply #1 on: November 07, 2011, 01:40:21 AM »
Just have another question related to MOSFET H-bridge.

If I use H-bridge like this one, would switching speed be affected by having pMOS and nMOS at the top side and nMOS only on the lower side?
« Last Edit: November 07, 2011, 03:44:54 PM by newInRobotics »
"Computer games don't affect kids; I mean if Pac-Man affected us as kids, we'd all be running around in darkened rooms, munching magic pills and listening to repetitive electronic music." - Kristian W

Offline Soeren

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Re: How to drive pMOS and nMOS H-bridge?
« Reply #2 on: November 07, 2011, 02:15:00 PM »
Hi,

Any chance you could post the schematics (or whatever it is) as pics, so they're visible?
Regards,
Søren

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Offline newInRoboticsTopic starter

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Re: How to drive pMOS and nMOS H-bridge?
« Reply #3 on: November 07, 2011, 03:20:13 PM »
Hi,

Any chance you could post the schematics (or whatever it is) as pics, so they're visible?

Done. It's in previous post. Also, link in previous post should point to the circuit as well  ;D
"Computer games don't affect kids; I mean if Pac-Man affected us as kids, we'd all be running around in darkened rooms, munching magic pills and listening to repetitive electronic music." - Kristian W

Offline Soeren

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Re: How to drive pMOS and nMOS H-bridge?
« Reply #4 on: November 07, 2011, 03:38:50 PM »
Hi,

Drive the P-channel MOSFETs gates to ground with NPN transistors (whose bases are driven from the same source as their respective N-channel MOSFET (with a base resistor of course and a base pull down if it's not driven actively low).
Regards,
Søren

A rather fast and fairly heavy robot with quite large wheels needs what? A lot of power?
Please remember...
Engineering is based on numbers - not adjectives

 


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