Searching \ for 'charge pump from pic' in subject line. ()
Make payments with PayPal - it's fast, free and secure! Help us get a faster server
FAQ page: massmind.org/techref/microchip/devices.htm?key=pic
Search entire site for: 'charge pump from pic'.

Truncated match.
PICList Thread
'charge pump from pic'
1998\04\05@122225 by Mitch Robbins

flavicon
face
I'm looking at the potential of using a pic output, possibly PWM, to drive a
charge pump/switched capacitor circuit for generation of negative voltages.
I need approx 10mA at -15v.  I'm trying to avoid that extra chip or 2.   A
home brew 7660?

I'm sure someone has been there before.  Has anyone had any luck in this
area, have circuit concepts, good references, or theory.

TIA
Mitch Robbins

1998\04\05@130039 by Michael Hagberg

flavicon
face
www.circuitcellar.com is a magazine that last month had an acrtile on charge
pumps.

michael


-----Original Message-----
From: Mitch Robbins <spam_OUTrobmTakeThisOuTspamAM2.COM>
To: .....PICLISTKILLspamspam@spam@MITVMA.MIT.EDU <PICLISTspamKILLspamMITVMA.MIT.EDU>
Date: Sunday, April 05, 1998 11:25 AM
Subject: charge pump from pic


{Quote hidden}

1998\04\05@185352 by Leon Heller

flavicon
picon face
In message <01bd60ae$bd691b40$c1afadce@robm>, Mitch Robbins
<.....robmKILLspamspam.....AM2.COM> writes
>I'm looking at the potential of using a pic output, possibly PWM, to drive a
>charge pump/switched capacitor circuit for generation of negative voltages.
>I need approx 10mA at -15v.  I'm trying to avoid that extra chip or 2.   A
>home brew 7660?
>
>I'm sure someone has been there before.  Has anyone had any luck in this
>area, have circuit concepts, good references, or theory.

I did this many years ago with a Z8, to get a -ve supply for the RS-232
interface, which used an op-amp.

Leon
--
Leon Heller: EraseMEleonspam_OUTspamTakeThisOuTlfheller.demon.co.uk http://www.lfheller.demon.co.uk
Amateur Radio Callsign G1HSM    Tel: +44 (0) 118 947 1424
See http://www.lfheller.demon.co.uk/dds.htm for details of my AD9850
DDS system. See " "/diy_dsp.htm for a simple DIY DSP ADSP-2104 system.

1998\04\06@004555 by tjaart

flavicon
face
Mitch Robbins wrote:

> I'm looking at the potential of using a pic output, possibly PWM, to drive a
> charge pump/switched capacitor circuit for generation of negative voltages.
> I need approx 10mA at -15v.  I'm trying to avoid that extra chip or 2.   A
> home brew 7660?
>
> I'm sure someone has been there before.  Has anyone had any luck in this
> area, have circuit concepts, good references, or theory.

You won't be able to do it directly if you want 10mA @ -15V. Assumingyou have perfect voltage
translation (which won't happen), you will have to
draw at least 30mA from a pin. This falls into the 'kaboom' section of the absolute
maximum specs.


--
Friendly Regards

Tjaart van der Walt
tjaartspamspam_OUTwasp.co.za

|--------------------------------------------------|
|                WASP International                |
|R&D Engineer : GSM peripheral services development|
|--------------------------------------------------|
|SMS +@spam@27832123443KILLspamspamsms.co.za  (160 chars max)|
|      http://www.wasp.co.za/~tjaart/index.html    |
|             Voice : +27-(0)11-622-8686           |
|              Fax : +27-(0)11-622-8973            |
|          WGS-84 : 26¡10.52'S 28¡06.19'E          |
|--------------------------------------------------|

1998\04\06@033044 by peter

flavicon
face
Tjaart van der Walt wrote:
>
> Mitch Robbins wrote:
>
> > I'm looking at the potential of using a pic output, possibly PWM, to drive a
> > charge pump/switched capacitor circuit for generation of negative voltages.
> > I need approx 10mA at -15v.  I'm trying to avoid that extra chip or 2.   A
> > home brew 7660?
> >
> > I'm sure someone has been there before.  Has anyone had any luck in this
> > area, have circuit concepts, good references, or theory.
>
> You won't be able to do it directly if you want 10mA @ -15V. Assumingyou have
perfect voltage
> translation (which won't happen), you will have to
> draw at least 30mA from a pin. This falls into the 'kaboom' section of the
absolute
> maximum specs.

If you have three pins to spare how about a ladder

pin3--Cap---@--->I----------@---------- 15V
           !               !
           !---I<--!      Cap
                   !       !
pin2--Cap---@--->I--@-------@
           !               !
           !---I<--!      Cap
                   !       !
pin1------->I-------@-------@
                           !
                          Cap
                           !
ground----------------------@-------

5 caps and 5 diodes


Peter Cousens
email: KILLspampeterKILLspamspamcousens.her.forthnet.gr  phone: + 3081 324450, 380534
snailmail:  Folia, Agia Fotini, Karteros, Heraklion  Crete, Greece.

1998\04\06@054641 by Octavio Nogueira

flavicon
face
>I'm looking at the potential of using a pic output, possibly PWM, to drive
a
>charge pump/switched capacitor circuit for generation of negative voltages.
>I need approx 10mA at -15v.  I'm trying to avoid that extra chip or 2.   A
>home brew 7660?
>
>I'm sure someone has been there before.  Has anyone had any luck in this
>area, have circuit concepts, good references, or theory.
>
>TIA
>Mitch Robbins
>

I did it, but to generate -5V for op-amp supply with just 2 caps and 2
diodes.

Octavio
======================================================
Octavio Nogueira  - e-mail:   RemoveMEnogueiraTakeThisOuTspammandic.com.br
http://www.geocities.com/~oct_nogueira
"ProPic" Production PIC Programmer Windows under US$20
======================================================

More... (looser matching)
- Last day of these posts
- In 1998 , 1999 only
- Today
- New search...