I have a voltage that's used to dim a 12V bulb and I'd like to use it to dim an LED instead. My plan so far is to use a triangle generator and a comparator to make a PWM signal with varying duty cycle.
I'd like to build everything into a PCB that replaces the bulb, so there wouldn't be a fixed voltage available but a varying voltage from 9V-11.5V, so the circuit needs to operate from that. All is going well, but I need to alter the signal used by the comparator so that it has a steeper slope.
In the circuit I've split the voltage into two sources in order to make it all work, and it looks like what I need would be have a steeper slope. The green line is the 9V-11.5V, and the purple line is what I need to convert it to for comparison with the triangle.
Is there a simple circuit that can do something like that? Maybe something using an adjustable voltage regulator?