PWM vs. Power_pwm

[umka]

What is the difference between a Power PWM and a PWM.

I want to make an ac motor controller only single phase. Was looking at the ex_power_pwm example but couldn't get it to work with a pic16f877a so guess power pwm is not supported by that chip.

[Guest_7068]

Most chips have a CCP(Capture Compare PWM) module using which you can do simple PWM- Change duty cycle, frequency on a single channel.

Few chips have a Power PWM module (18FX331), where you can generate synchronous PWM outputs. 3 Units - 6 Channels for 18F2x31 and 4 Units and 8 Channels for the 18F4x31 chips
This allows up to 4 different duty cycle settings, where the channels can be setup in independent or complimentary mode (out of phase).
So, the power PWM module is not too different from a regular PWM, but has a few more features and you can read about them in the 18F4431 data sheet.

BTW, is there any PIC16 that has a Power PWM on it?

[umka]

So for me building an AC power source with variable frequency i would be best getting one of the chips with power_PWM over CCP PWM?

[Ttelmah]

Not really.
The standard PWM, gives you basically two channels, for which you can set one frequency, and independantly, the pulse width of each. For a single AC channel, this should be enough. The power PWM, is great for things like synthesising three phase control.

Best Wishes