varying duty cycle on a power inverter 1

[jbeatty]

I have a circuit for a modified square wave inverter switched by a 555 astable driving two banks of mosfets (via alternate outputs on a 4017 counter) switching 12v into an 8-0-8 transformer primary. Question: how can I add variable duty cycle for current control? can I just alter the 555 timer to a fixed frequency/variable duty cycle design or will that "upset" the 4017? what would be an alternative design?
Thank you.

 

[nbucska]

The simplest would be to use a dual timer
The oscillator drives the second one acting
as a single shot with voltage controlled
duty cycle. <nbucska@pcperipherals.com>

 

[jbartos]

Suggestion: Provide more info about the variable duty cycle, e.g. discrete/digital or analog, etc.