PWM Chip

[R.G.]

The recent stuff on the stuttering pedal circuit made me think for a bit about how I'd do a good PWM. I had to go back a ways.

The 555 or some opamps and comparators is what everyone thinks of, but the SG3524 switching power supply chip does a dandy analog pwm all in one chip. It's got RC timer, PWM comparator and some opamps on one chip along with either open circuit or totem pole drivers. I think this one chip would do a PWM solution when combined with a well designed JFET switch to do things like:

PWM phaser
PWM tremolo
PWM ring modulator
PWM variable filters ala the MXR version
variable four pole lowpass filters with resonance.

It will do either single or opposite phase pwm - I think.

[gez]

Data sheet here:

http://www.st.com/stonline/books/pdf/docs/1431.pdf

Haven't read it yet, just want to read what the gurus come up with!

[Marcos - Munky]

I think this one chip would do a PWM solution when combined with a well designed JFET switch to do things like:

PWM phaser
PWM tremolo
PWM ring modulator
PWM variable filters ala the MXR version
variable four pole lowpass filters with resonance.

Sounds very cool, R.G.

[brett]

If you could trigger modulation from a decent signal level (>1mV ??), you could probably overcome the "noisy when it's supposed to be quiet" problem that plagues ring modulators.

Go for it!