Gate Driver Modification not working

[Bakez]

I have modified a concept2 gate driver

I have a low pass filter and then I want to clamp the voltage of this from 0.7V to -0.7V which I feed into an opamp

The diode used to clamp to -0.7V however stops the gate driver working, does anyone have an ideas why?

You can see my schematic

FWIW the gate driver works perfectly without this diode in.

Gate Driver swings from -10 to +15V

 

[andre_luis]

What ground reference is being used on that operational amplifier placed at output of the driver ?

 

[FvM]

I guess, the gate driver isn't prepared to drive statical output loads. You may want to try with higher resistor values than 1k.

 

[Bakez]

What ground reference is being used on that operational amplifier placed at output of the driver ?

This isn't a problem (yet)

The gate driver works with the RC and one of the diodes in. Its the diode that is clamping to -0.7V that stops the driver working

I see the voltage that Im interested in (input to the opamp) as -0.684... like it should be, but the gate voltage is just stuck at -2.8 or similar and never changes

- - - Updated - - -

I guess, the gate driver isn't prepared to drive statical output loads. You may want to try with higher resistor values than 1k.

I think this could be good start, but higher resistor values mean that the low pass RC starts attenuating what Im interested in too much. Unless I have 1pF capacitors.

 

[andre_luis]

but higher resistor values mean that the low pass RC starts attenuating what Im interested in too much

Depending on circuit topology applied - which probably should be Half-Bridge in your case - a little delay could be desirable for ensure generate a dead time between conduction of low-high side elements ( although probably such feature is already built on above gate driver IC ).