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Has any one tried this..

Started by Maynard A. Philbrook Jr. June 11, 2014
Making a small hand tool and want to condense part count to min..
I need a +/- 5 volt rail, also I need a fast running +/- square pulse
and the inverter section at the collector of Q1 supplies +/- 5 volts,
which is perfect.
 I take one op-amp out of four and made the standard relaxation 
oscillator for the square wave, ~20Khz. it starts off with 0 volts
at the Vee but the inverter will bring that up to -5 volts and the
other remaining 3 op-amps will have the +/- rail voltage for the
rest of the circuit. The bread boarded this section and it works,
need to do the rest if this works remains ok. currently is at 
50mA usage on the 9V battery.
 
 How any one done this before?


   9V         .------.
   +----------+ 7805 +++-----Vcc of LM324
   |          '--+---' +
  ---            |     |
   -            ===    |
   |            GND    |
  ===                  |
  GND                  +
                       |
                       |
                       | Q1
          R1 20k       +
           ___       |< PNP
 from >> -|___|+----+|
                     |\
SQR Wave generator     +   10V ZENER
from one LM234 Section |
~20kHz                 +-----+z<+----------+
                       |   C      A        ++ to (Vee) of LM324
                       |                   |
                       C|                  +
                       C| 10mH            ---
                       C|  L1             ---10u
                       |                   |
                       |                  ===
                      ===                 GND
                      GND
(created by AACircuit v1.28.6 beta 04/19/05 www.tech-chat.de)

Jamie
On Wed, 11 Jun 2014 21:07:29 -0400, "Maynard A. Philbrook Jr."
<jamie_ka1lpa@charter.net> wrote:

>Making a small hand tool and want to condense part count to min.. >I need a +/- 5 volt rail, also I need a fast running +/- square pulse >and the inverter section at the collector of Q1 supplies +/- 5 volts, >which is perfect. > I take one op-amp out of four and made the standard relaxation >oscillator for the square wave, ~20Khz. it starts off with 0 volts >at the Vee but the inverter will bring that up to -5 volts and the >other remaining 3 op-amps will have the +/- rail voltage for the >rest of the circuit. The bread boarded this section and it works, >need to do the rest if this works remains ok. currently is at >50mA usage on the 9V battery. > > How any one done this before? > > > 9V .------. > +----------+ 7805 +++-----Vcc of LM324 > | '--+---' + > --- | | > - === | > | GND | > === | > GND + > | > | > | Q1 > R1 20k + > ___ |< PNP > from >> -|___|+----+| > |\ >SQR Wave generator + 10V ZENER >from one LM234 Section | >~20kHz +-----+z<+----------+ > | C A ++ to (Vee) of LM324 > | | > C| + > C| 10mH --- > C| L1 ---10u > | | > | === > === GND > GND >(created by AACircuit v1.28.6 beta 04/19/05 www.tech-chat.de) > >Jamie
This is sorta similar, but it has feedback to define the negative voltage. https://dl.dropboxusercontent.com/u/53724080/Circuits/Power/DC_DC2.jpg You might look at charge pump chips, too, like LM2664. No inductor needed, and you might be able to swipe the clock output. -- John Larkin Highland Technology Inc www.highlandtechnology.com jlarkin at highlandtechnology dot com Precision electronic instrumentation
In article <em2ip99kh5nkuenn5son1ks3vd7v0ak18h@4ax.com>, 
jjlarkin@highNOTlandTHIStechnologyPART.com says...
> > > > How any one done this before? > > > > > > 9V .------. > > +----------+ 7805 +++-----Vcc of LM324 > > | '--+---' + > > --- | | > > - === | > > | GND | > > === | > > GND + > > | > > | > > | Q1 > > R1 20k + > > ___ |< PNP > > from >> -|___|+----+| > > |\ > >SQR Wave generator + 10V ZENER > >from one LM234 Section | > >~20kHz +-----+z<+----------+ > > | C A ++ to (Vee) of LM324 > > | | > > C| + > > C| 10mH --- > > C| L1 ---10u > > | | > > | === > > === GND > > GND > >(created by AACircuit v1.28.6 beta 04/19/05 www.tech-chat.de) > > > >Jamie > > This is sorta similar, but it has feedback to define the negative voltage. > > https://dl.dropboxusercontent.com/u/53724080/Circuits/Power/DC_DC2.jpg > > > You might look at charge pump chips, too, like LM2664. No inductor needed, and > you might be able to swipe the clock output. >
The idea was to not use any extra chips, as it is, I think the sum of 4 op-amps total is all I need and the 324 fits that. I tried the charge pump method but was having problems obtaining the output voltage. The zener is there to back bleed and also serves as the diode needed for the (-) output. I'll look at yours. Jamie
On Wed, 11 Jun 2014 21:07:29 -0400, "Maynard A. Philbrook Jr."
<jamie_ka1lpa@charter.net> wrote:

>Making a small hand tool and want to condense part count to min.. >I need a +/- 5 volt rail, also I need a fast running +/- square pulse >and the inverter section at the collector of Q1 supplies +/- 5 volts, >which is perfect. > I take one op-amp out of four and made the standard relaxation >oscillator for the square wave, ~20Khz. it starts off with 0 volts >at the Vee but the inverter will bring that up to -5 volts and the >other remaining 3 op-amps will have the +/- rail voltage for the >rest of the circuit. The bread boarded this section and it works, >need to do the rest if this works remains ok. currently is at >50mA usage on the 9V battery. > > How any one done this before? > > > 9V .------. > +----------+ 7805 +++-----Vcc of LM324 > | '--+---' + > --- | | > - === | > | GND | > === | > GND + > | > | > | Q1 > R1 20k + > ___ |< PNP > from >> -|___|+----+| > |\ >SQR Wave generator + 10V ZENER >from one LM234 Section | >~20kHz +-----+z<+----------+ > | C A ++ to (Vee) of LM324 > | | > C| + > C| 10mH --- > C| L1 ---10u > | | > | === > === GND > GND >(created by AACircuit v1.28.6 beta 04/19/05 www.tech-chat.de) > >Jamie
Here's on that produces +5V and -12V... <http://www.analog-innovations.com/SED/OldStyleBuckSwitcherWithAddedNegativeOutput.pdf> Just change the feedback to get +/-5V ...Jim Thompson -- | James E.Thompson | mens | | Analog Innovations | et | | Analog/Mixed-Signal ASIC's and Discrete Systems | manus | | San Tan Valley, AZ 85142 Skype: skypeanalog | | | Voice:(480)460-2350 Fax: Available upon request | Brass Rat | | E-mail Icon at http://www.analog-innovations.com | 1962 | I love to cook with wine. Sometimes I even put it in the food.
On Wednesday, June 11, 2014 9:07:29 PM UTC-4, Maynard A. Philbrook Jr. wrote:
> Making a small hand tool and want to condense part count to min.. > > I need a +/- 5 volt rail, also I need a fast running +/- square pulse > and the inverter section at the collector of Q1 supplies +/- 5 volts, > which is perfect. > > I take one op-amp out of four and made the standard relaxation > oscillator for the square wave, ~20Khz. it starts off with 0 volts > at the Vee but the inverter will bring that up to -5 volts and the > other remaining 3 op-amps will have the +/- rail voltage for the > rest of the circuit. The bread boarded this section and it works, > need to do the rest if this works remains ok. currently is at > 50mA usage on the 9V battery. > > How any one done this before? > > > > 9V .------. > +----------+ 7805 +++-----Vcc of LM324 > | '--+---' + > --- | | > - === | > | GND | > === | > GND + > | > | > | Q1 > R1 20k + > ___ |< PNP > from >> -|___|+----+| > |\ > SQR Wave generator + 10V ZENER > from one LM234 Section | > ~20kHz +-----+z<+----------+ > | C A ++ to (Vee) of LM324 > | | > C| + > C| 10mH --- > C| L1 ---10u > | | > | === > === GND > GND > > (created by AACircuit v1.28.6 beta 04/19/05 www.tech-chat.de)
That's an inverting boost. You could cut the battery drain a lot by blocking Q1's drive when Vee = -5v. Cheers, James Arthur
"Maynard A. Philbrook Jr." <jamie_ka1lpa@charter.net> Wrote in message:
> Making a small hand tool and want to condense part count to min.. > I need a +/- 5 volt rail, also I need a fast running +/- square pulse > and the inverter section at the collector of Q1 supplies +/- 5 volts, > which is perfect. > I take one op-amp out of four and made the standard relaxation > oscillator for the square wave, ~20Khz. it starts off with 0 volts > at the Vee but the inverter will bring that up to -5 volts and the > other remaining 3 op-amps will have the +/- rail voltage for the > rest of the circuit. The bread boarded this section and it works, > need to do the rest if this works remains ok. currently is at > 50mA usage on the 9V battery. > > How any one done this before? > > > 9V .------. > +----------+ 7805 +++-----Vcc of LM324 > | '--+---' + > --- | | > - === | > | GND | > === | > GND + > | > | > | Q1 > R1 20k + > ___ |< PNP > from >> -|___|+----+| > |\ > SQR Wave generator + 10V ZENER > from one LM234 Section | > ~20kHz +-----+z<+----------+ > | C A ++ to (Vee) of LM324 > | | > C| + > C| 10mH --- > C| L1 ---10u > | | > | === > === GND > GND > (created by AACircuit v1.28.6 beta 04/19/05 www.tech-chat.de) > > Jamie >
The LM324 will never do a full swing square wave at 20khz, because of its slew rate. --
On Thursday, June 12, 2014 6:08:40 AM UTC+1, bitrex wrote:

> The LM324 will never do a full swing square wave at 20khz, because > of its slew rate.
6kHz power bandwidth ISTR NT
On Wednesday, June 11, 2014 9:07:29 PM UTC-4, Maynard A. Philbrook Jr. wrote:
> Making a small hand tool and want to condense part count to min.. > > I need a +/- 5 volt rail, also I need a fast running +/- square pulse > > and the inverter section at the collector of Q1 supplies +/- 5 volts, > > which is perfect. > > I take one op-amp out of four and made the standard relaxation > > oscillator for the square wave, ~20Khz. it starts off with 0 volts > > at the Vee but the inverter will bring that up to -5 volts and the > > other remaining 3 op-amps will have the +/- rail voltage for the > > rest of the circuit. The bread boarded this section and it works, > > need to do the rest if this works remains ok. currently is at > > 50mA usage on the 9V battery. > > > > How any one done this before?
Not anyone who knows what they're doing. Why on earth would you discharge the output capacitor through the zener??? No wonder it's pulling 50mA, ridiculous.
> > > > > > 9V .------. > > +----------+ 7805 +++-----Vcc of LM324 > > | '--+---' + > > --- | | > > - === | > > | GND | > > === | > > GND + > > | > > | > > | Q1 > > R1 20k + > > ___ |< PNP > > from >> -|___|+----+| > > |\ > > SQR Wave generator + 10V ZENER > > from one LM234 Section | > > ~20kHz +-----+z<+----------+ > > | C A ++ to (Vee) of LM324 > > | | > > C| + > > C| 10mH --- > > C| L1 ---10u > > | | > > | === > > === GND > > GND > > (created by AACircuit v1.28.6 beta 04/19/05 www.tech-chat.de) > > > > Jamie
In article <ad80a269-1e3d-4654-86f7-9547373d13d1@googlegroups.com>, 
meow2222@care2.com says...
> > On Thursday, June 12, 2014 6:08:40 AM UTC+1, bitrex wrote: > > > The LM324 will never do a full swing square wave at 20khz, because > > of its slew rate. > > 6kHz power bandwidth ISTR > > > NT
As stated, square wave comes from collector, not op-amp output, I use the rounded corner triangle wave to drive the PNP which saturates early.. Jamie
In article <6OOdnbcMqLv4qwTOnZ2dnUVZ_jadnZ2d@earthlink.com>, 
bitrex@de.lete.earthlink.net says...
> > "Maynard A. Philbrook Jr." <jamie_ka1lpa@charter.net> Wrote in message: > > Making a small hand tool and want to condense part count to min.. > > I need a +/- 5 volt rail, also I need a fast running +/- square pulse > > and the inverter section at the collector of Q1 supplies +/- 5 volts, > > which is perfect. > > I take one op-amp out of four and made the standard relaxation > > oscillator for the square wave, ~20Khz. it starts off with 0 volts > > at the Vee but the inverter will bring that up to -5 volts and the > > other remaining 3 op-amps will have the +/- rail voltage for the > > rest of the circuit. The bread boarded this section and it works, > > need to do the rest if this works remains ok. currently is at > > 50mA usage on the 9V battery. > > > > How any one done this before? > > > > > > 9V .------. > > +----------+ 7805 +++-----Vcc of LM324 > > | '--+---' + > > --- | | > > - === | > > | GND | > > === | > > GND + > > | > > | > > | Q1 > > R1 20k + > > ___ |< PNP > > from >> -|___|+----+| > > |\ > > SQR Wave generator + 10V ZENER > > from one LM234 Section | > > ~20kHz +-----+z<+----------+ > > | C A ++ to (Vee) of LM324 > > | | > > C| + > > C| 10mH --- > > C| L1 ---10u > > | | > > | === > > === GND > > GND > > (created by AACircuit v1.28.6 beta 04/19/05 www.tech-chat.de) > > > > Jamie > > > > The LM324 will never do a full swing square wave at 20khz, because of >its slew rate.
Correct, it does not have the BW to do that but it serves as the ref to drive the PNP. Q1 saturates very early and when turned off it gives acceptable results. Op-amp output base ~ 0.5v and produces a slightly rounded triangle. Time constant on L helps greatly on generating the square at the collector, too. I will replace the 7805 with a LDO type, I used that on the bench because I have a couple hundred of them to burn up. Jamie