Mosaic
Well-Known Member
I am doing an experiment to build a 400W RF class E amplifier at about 4Mhz.
This means controlling the duty cycle of the pulses governs the amplifier efficiency.
I am considering the 48Mhz 18F25J50
https://ww1.microchip.com/downloads/en/DeviceDoc/39931d.pdf
Given the PWM Period:
PWM Period = [(PR2) + 1] • 4 • TOSC•(TMR2 Prescale Value)
It seems that a PR2 of 2 is the max I can get for a 4Mhz PWM drive.
Which just gives 0,25,50,100% PWM settings. Not much control.
The alternative is to make a one shot timer which is driven by a 4Mhz click line and then alter PWM by altering the one shot duration.
Any suggestions on this?
This means controlling the duty cycle of the pulses governs the amplifier efficiency.
I am considering the 48Mhz 18F25J50
https://ww1.microchip.com/downloads/en/DeviceDoc/39931d.pdf
Given the PWM Period:
PWM Period = [(PR2) + 1] • 4 • TOSC•(TMR2 Prescale Value)
It seems that a PR2 of 2 is the max I can get for a 4Mhz PWM drive.
Which just gives 0,25,50,100% PWM settings. Not much control.
The alternative is to make a one shot timer which is driven by a 4Mhz click line and then alter PWM by altering the one shot duration.
Any suggestions on this?