transformer differentiating waveform at its input.

[analog_match]

I was trying to provide gate drive to an FET in a simple buck (see circuit.pdf) and was using a transformer for the purpose. I was first testing out the transformer by itself just to make sure it is OK. But when I give a square wave i/p (10V p-p 50% duty 150KHz) I get the waveform as attached (see weirdxmerout.pdf). It seems like the o/p of the transformer is the differentiation of the input. I verified this by changing the input to a triangular wave and the output became square of the same frequency. Why is my transformer differentiating the input?

 

[ljcox]

Because of the "Ohm's Law" of inductance.

v = L di/dt.

I investigated the same idea & concluded that an optio coupler would be better.

Attached are 2 examples.

I have not tried this technique, but, after reading the data sheets, it looks very workable.

Please let me know the result if you try it.