CMOS Pulsewidth Modulators

synthmonger

The 71k resistor on pin 1 of the 4007 may need to be adjusted on different power supplies. Otherwise, should work fine as is!

cmos_pulsewidth_modulators.bmp

Description:

Download

Filename:

cmos_pulsewidth_modulators.bmp

Filesize:

96.31 KB

Downloaded:

1496 Time(s)

DGTom · Posted: Tue Apr 28, 2009 2:12 am Post subject:

Cool! I have your 40106 VCO on my breadboard at the moment, would this be best used straight off the output pin or from one or other of the "proper" waveform outs?

synthmonger · Posted: Tue Apr 28, 2009 5:02 am Post subject:

If you're using the VCO with the 4016 switch that is acting as a voltage controlled variable resistor on one of the spare 40106 gates yes it would work. Triggers are the only thing this can't handle. Anything else, normal square, triangle, sine, saw etc will work. Negative voltages too.

synthmonger · Posted: Tue Apr 28, 2009 6:23 am Post subject:

For an audio clip you can refer to my Pulse Monger which uses similar circuitry. I used transistors instead of MOS for it but it sounds exactly the same.

http://www.youtube.com/watch?v=_TksWPbagsM

More to come soon!

synthmonger · Posted: Tue Apr 28, 2009 8:53 am Post subject:

Board layout is done. I have 6 boards with pnp on them and ready to etch. After I etch and dirll them I'm going to keep two and put the other 4 in my Etsy store.

cmos_PWmods_board.jpg

Description:

Filesize:

137.41 KB

Viewed:

421 Time(s)

This image has been reduced to fit the page. Click on it to enlarge.

DGTom · Posted: Wed Apr 29, 2009 4:01 am Post subject:

I've been playing around with your 'super simple vco' with a transistor for the CV in, cos I blew my only (for the time being) 4007 up Embarassed

w/ the 4007 I used the current source drawing (I think) slacker posted up here, that worked great.

Gonna search for the info on the 4016 idea now Very Happy

So these are really intended as standalone PWM everything! Nice.

monokinetic · Joined: Aug 01, 2006 Posts: 100 Location: prague

Hey synthie!

Hmmm, sounds intriguing Smile

I had a quick look at the PCB and schematic (Bananas are indeed delish!). But I'm not 100 percent sure I understand what you have here:

It seems to be 2x PWM oscillators, CV controllable. Is that correct?

I think there are 6 pots on the PCB, but only 4 on the schematic (or is the trim on the front panel?).

Sorry if these are obvious questions, I'm just double-checking before I head over to your etsy store, assuming this is what I think it is Wink

David

synthmonger · Posted: Wed Apr 29, 2009 12:20 pm Post subject:

synthmonger · Posted: Thu Apr 30, 2009 3:39 am Post subject:

I added 4 PWM boards to my site. Here's the link!

http://www.etsy.com/view_listing.php?listing_id=24383500