The title says it all. I am using a microcontroller which will output a PWM signal. This PWM needs to control voltage level to a motor. Normally I'd use the PWM to drive a FET which would directly drive the motor. However in this case the motor has a speed sensor which doesn't work properly with a PWM, so I need a constant, but variable, voltage output to preserve the speed sensor's operation.
So I thought: Why not filter the PWM output to a constant voltage level, since a 50% duty cycle PWM at 12V is equivalent in power to a constant 6volts, and a 75% duty cycle is equivalent to a constant 9Volts. But how to make the constant voltage from PWM?
I thought that it might work with a diode, cap to gnd after the diode, and linear drive transistor to the motor, but it didn't work so well. Maybe I had something wrong...
Anyone got any ideas?
Note: I have to use a PWM as I only have one pin available so can't use a DAC.
Thanks!!!
So I thought: Why not filter the PWM output to a constant voltage level, since a 50% duty cycle PWM at 12V is equivalent in power to a constant 6volts, and a 75% duty cycle is equivalent to a constant 9Volts. But how to make the constant voltage from PWM?
I thought that it might work with a diode, cap to gnd after the diode, and linear drive transistor to the motor, but it didn't work so well. Maybe I had something wrong...
Anyone got any ideas?
Note: I have to use a PWM as I only have one pin available so can't use a DAC.
Thanks!!!