15V to 5V circuit modification (RC)?

[BlueBill]

The circuit below works great at 15VDC, what changes do I need to make to get it to operate at 5VDC. Should I just decrease the cap size by a factor of three? Ideally I'd like to use a 0.01µF cap and adjust the other resistor values accordingly.

The input to the diode is from a comparator at 120Hz with a short negative going pulse width of 1.8ms and a high of 14.9ms. The comparator can sink 20ma.

Thanks in advance.

Bill

[lapm]

So input its that sort of pulses, what you need output from this circuit? Similar pulses? Also second pamps negative signal is going to have effect on where it will output high...

[Kdog44]

What is the output of the circuit suppose to look like?
What is the second input to the most right op-amp?

[BlueBill]

What is the output of the circuit suppose to look like?
What is the second input to the most right op-amp?

I'll post the waveform today, as for pin 6 it's a trimpot (voltage divider).
Here's the signal (yellow) I'd like to replicate at with a 5V supply. The purple trace is the pulse that pulls the diode to near ground.