smellsofbikes
V2PWM
Quad op-amp wired sequentially as oscillator (frequency set by VR17), square-wave generator (with breakout testpoint), triangle-wave generator (with breakout testpoint) and comparator with voltage reference, making a voltage-to-PWM converter. The voltage reference pot doesn't need high-value resistors on either side, but this (and the similar bias for U1C) is the largest power draw in the whole circuit so having them reduces the power it uses. I added a connector between the Vref pot and the comparator so you can use an external input to set your duty cycle. This is intended for the current-limiter above: using a cheap opamp as a comparator is a bad idea for most applications because it has slow slew and would leave a FET in its active region for far, far too long and allow it to overheat.
V- is 0 volts, V+ is 5-15 volts.
V2PWM
Quad op-amp wired sequentially as oscillator (frequency set by VR17), square-wave generator (with breakout testpoint), triangle-wave generator (with breakout testpoint) and comparator with voltage reference, making a voltage-to-PWM converter. The voltage reference pot doesn't need high-value resistors on either side, but this (and the similar bias for U1C) is the largest power draw in the whole circuit so having them reduces the power it uses. I added a connector between the Vref pot and the comparator so you can use an external input to set your duty cycle. This is intended for the current-limiter above: using a cheap opamp as a comparator is a bad idea for most applications because it has slow slew and would leave a FET in its active region for far, far too long and allow it to overheat.
V- is 0 volts, V+ is 5-15 volts.