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Inverters built on PIC16F877A, short circuit and very noisy

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emanuelpic

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Inverters

Hi everybody I about to finish building my sine inverter with carrier frequency 2000hz and output voltage 110 v ac using PIC 16f877A now my problem is when I switch the N channel CMOS fet H bridge suddenly the circuit becomes very noisy and there is a short circuit on power supply. can anybody help me to overcome this short circuit and reduce the noise.
Thanx
 

sahu

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Re: Inverters

emanuelpic said:
Hi everybody I about to finish building my sine inverter with carrier frequency 2000hz and output voltage 110 v ac using PIC 16f877A now my problem is when I switch the N channel CMOS fet H bridge suddenly the circuit becomes very noisy and there is a short circuit on power supply. can anybody help me to overcome this short circuit and reduce the noise.
Thanx
may b i can help u pl give all deteails
 

dick_freebird

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Inverters

You need to hook up a 'scope and look at some things.

First off, huge ground currents need to be kept to very
tight, short loops. If they can, they will corrupt your
analog and possibly digital sections. Among common
behaviors from this, is a reswitching or chatter on the
FET drive signals, which can suck a lot of current.

Second, if you are using an H-bridge driver IC to run
the power FETs, look for guidance on anti-shoot-through
timing and how to ensure no cross-conduction. That is
one way to get really, really bad ground currents.

You may as well post a schematic.
 

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