How to calculate the PWM duty cycle for Solenoid current control
I am trying to design a current control driver for Solenoid. I know the peak and the holding current range for solenoid.
How would I find the PWM duty cycle based on the current that I need to control?
Solenoid resistance at different temperature
1.1 Ohm @ 20 C 1.61 Ohm @ 150 C 0.85 Ohm @ -40 C
Voltage Range 9 V min 13 V Normal 16 V Max
Disengaging clutch current 7 A min & Max 16 A, but I would like to limit the max current up to 10 A only.
Holding current for clutch is 1.2 A min to 2.2 Max
Frequency Range: 1000 to 50 Hz
Microcontroller is used for PWM output.
I want to design a current control circuitry using N MOSFETS for Solenoid
I am using current sense opamp to monitor the current through solenoid. I am using 20 m Ohm resistance for the current measurement.
I am trying to figure out how to calculate the PWM duty cycle for the disengaging current & holding current?
Should I go 100% duty cycle and control the current once the clutch is disengaged by the solenoid?