Author Topic: Charge Pump Circuits  (Read 231 times)

drog_trog

  • Transistor Tickler
  • **
  • Posts: 118
    • View Profile
Charge Pump Circuits
« on: June 20, 2018, 10:01:49 AM »
Here are 2 charge pumps that go from 9v to 18v, both are a bit different but which is best to use
1)


2)



midwayfair

  • Electron Doctor
  • *****
  • Posts: 6836
  • Jon P
    • View Profile
    • Midway Fair
Re: Charge Pump Circuits
« Reply #1 on: June 20, 2018, 11:16:46 AM »
Datasheets for charge pump chips usually have example circuits and they will tell you the benefits of a particular circuit.

Besides, if we don't know what you're building, even if we had an opinion on the bestness of one of those circuits, it would be meaningless without knowing which charge pump chip you're using for which pedal.

That said, the second looks like it's the same thing but drawn wrong. If you look through some datasheets you might be able to find that circuit and figure out what it's for, though.
Myself's music & things I make: http://jonpattonmusic.com. My band: http://midwayfair.org. PCBs of my designs from: http://www.1776Effects.com (Bearhug Comp & Cardinal Harmonic Trem); http://www.jmkpcbs.com (Hamlet+ delay & Blue Warbler envelope vibe); Snow Day OD/Flabulanche: www.madbeanpedals.com

drog_trog

  • Transistor Tickler
  • **
  • Posts: 118
    • View Profile
Re: Charge Pump Circuits
« Reply #2 on: June 22, 2018, 04:59:24 AM »
I wasnt sure on which circuit to use for the 18V effect-Toneczar Openhaus

maybe this would be ok

« Last Edit: June 22, 2018, 07:54:55 AM by drog_trog »

Boba7

  • Electron Doctor
  • *****
  • Posts: 667
    • View Profile
Re: Charge Pump Circuits
« Reply #3 on: June 22, 2018, 11:27:23 AM »
Looks fine. Use a 12v zener if you use a tc1044 or 7660 chip.

Also I found that filtering the output makes a huge difference regarding noise. Put a 22-100r with a 47-100uf to ground at the output. I would also replace the 5817 with a 22r
« Last Edit: June 22, 2018, 11:29:24 AM by Boba7 »

Boba7

  • Electron Doctor
  • *****
  • Posts: 667
    • View Profile
Re: Charge Pump Circuits
« Reply #4 on: June 22, 2018, 11:35:58 AM »
Here's the charge pump I've been using lately (followed by a voltage divider that you can ignore / the 10ks and 10uf)
Compared to other charge pumps I've used its MUCH more quiet, probably due to the filtering of both the input and the output.

(osc pads should be jumpered with tc1044/icl7660s or unconnected with lt1054)

drog_trog

  • Transistor Tickler
  • **
  • Posts: 118
    • View Profile
Re: Charge Pump Circuits
« Reply #5 on: June 22, 2018, 01:48:38 PM »
Thanks

Rockhorst

  • Electron Doctor
  • *****
  • Posts: 779
    • View Profile
Re: Charge Pump Circuits
« Reply #6 on: June 23, 2018, 05:58:09 AM »
Your circuit 1 connects pins 1 and 8 but mentions a 1054 chip. Connecting those two pins only applies to the 7660S and 1044 chips.

These things are sometimes noise inducing (whine), it's a bit of EM voodoo but what I've found consistently prevents this is:

- no polygons (ground, power, whatever) under the charge pump on the PCB
- additional MLCC filter caps on the output as close as possible to anything using the power (so a cap for every opamp for instance)
- A dedicated power track on the pcb, 20 or 24 mills and preferably no 'daisy chaining' but direct connections to the source

Another way to prevent noise is to put the charge pump on a separate board and put it on the side wall of the enclosure so that it's at a 90 degree angle to your circuit. I did this on a circuit once and it went from unusable to silent with just that.

Good luck :)
« Last Edit: June 23, 2018, 05:59:53 AM by Rockhorst »