i am using Ir2112 to drive mosfet, i measured between Ho and Vs which is (Vgs ) and it was 12 volt but the signal wasn't pure square there were a little Curvature in the up side and low side of the pulse . i don't know if this curvature is normal or i can enhance the circuit performance to get it pure square .I sent you the complete circuit for dc-dc buck converter which is drived by micro controller , i attached the a picture for the wave

Attached Thumbnails

 

I don't see the circuit.

How are you measuring this floating voltage? You should do a differential measurement using two scope inputs with two 10:1 probes. Set both channels to the same voltage sensitivity but invert one of the inputs. That should give a good differential measurement.

 

I don't see the circuit.

How are you measuring this floating voltage? You should do a differential measurement using two scope inputs with two 10:1 probes. Set both channels to the same voltage sensitivity but invert one of the inputs. That should give a good differential measurement.

sorry i will attach the circuit later
i measured it by set the input probe on gate and the ground on source

 

Are you using on/off control or PWM?
Max.

 

Are you using on/off control or PWM?
Max.

pwm is used

 

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i measured it by set the input probe on gate and the ground on source

That means the oscilloscope ground and chassis is floating at the source voltage. That may be the problem. Try the differential measurement as I suggested.

 

I don't see the circuit.

How are you measuring this floating voltage? You should do a differential measurement using two scope inputs with two 10:1 probes. Set both channels to the same voltage sensitivity but invert one of the inputs. That should give a good differential measurement.

thank you
I tried this method and it gives good signal but it is 14 volt is that normal ?