> I have an opamp with a 10 volt positive supply and need the output to
>> swing to about 16 volts. I was thinking I could add a paralleled 6.8
>> volt zener, a cap, and a floating power supply at the opamp output. >>
>> The power supply could be a PV optocoupler like this:
>>
>>formatting link>>
>> My load is obviously light, a varicap in fact.
>
> Not seeing the need for a zener...
>
> I take it mean the standard non-inverting OA with the PV in series with OA output, and a high-Z resistor feedback divider from the composite output (PV cathode) to OA (-). Loop gain, which should be very large attenuates noise and the unknowns at the composite output.
>
> Is there some reason you can't drive current through the detector? Maybe too non-linearizing...
>
> They datasheet is so fixed on detector Voc Isc with input LED drive, it's almost tempting to use the LED drive to modulate the final output into place.
Not clear to me from JL's original post if the op amp has a negative supply rail so that even after the 7V output offset the varicap can be biased below 7V?
Modulating the PV LED drive could have horrible delays and upset the dynamics?
piglet