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From: Jamie on 31 Jan 2010 20:59
MooseFET wrote:

> On Jan 31, 3:03� pm, Jamie
> <jamie_ka1lpa_not_valid_after_ka1l...(a)charter.net> wrote:
>
>>MooseFET wrote:
>>
>>>On Jan 31, 7:29 am, Glen Walpert <nos...(a)null.void> wrote:
>>
>>>>On Sat, 30 Jan 2010 10:05:13 -0800, John Larkin wrote:
>>
>>>>>On Sat, 30 Jan 2010 09:58:57 -0600, mook Johnson <m...(a)mook.net> wrote:
>>
>
> If you want more efficient operation, you could do this:
>
> Version 4
> SHEET 1 880 680
> WIRE 240 -80 64 -80
> WIRE 240 -64 240 -80
> WIRE -320 -48 -448 -48
> WIRE 64 -48 64 -80
> WIRE 64 -48 -320 -48
> WIRE 96 -16 80 -16
> WIRE -320 48 -320 -48
> WIRE -320 64 -320 48
> WIRE -160 128 -320 128
> WIRE 80 128 80 -16
> WIRE 80 128 64 128
> WIRE 240 128 240 32
> WIRE 272 128 240 128
> WIRE 400 128 336 128
> WIRE 720 128 400 128
> WIRE 240 144 240 128
> WIRE 720 160 720 128
> WIRE 400 176 400 128
> WIRE -320 192 -320 128
> WIRE -160 192 -320 192
> WIRE 144 192 64 192
> WIRE -448 256 -448 -48
> WIRE -416 256 -448 256
> WIRE -160 256 -416 256
> WIRE 96 256 64 256
> WIRE 240 256 240 224
> WIRE 240 256 96 256
> WIRE 400 256 400 240
> WIRE 400 256 240 256
> WIRE 512 256 400 256
> WIRE 720 256 720 224
> WIRE 720 256 592 256
> WIRE 96 288 96 256
> WIRE -416 304 -416 256
> WIRE 848 304 784 304
> WIRE -320 320 -320 272
> WIRE -192 320 -320 320
> WIRE 144 320 144 192
> WIRE 144 320 -192 320
> WIRE -320 336 -320 320
> WIRE -192 336 -192 320
> WIRE 720 352 400 352
> WIRE 144 368 144 320
> WIRE 400 368 400 352
> WIRE 400 368 144 368
> WIRE -416 400 -416 384
> WIRE -192 400 -320 400
> FLAG 96 288 0
> FLAG -416 400 0
> FLAG -320 400 0
> FLAG 848 304 0
> SYMBOL Misc\\NE555 -48 160 R180
> SYMATTR InstName U1
> SYMBOL voltage -416 288 R0
> WINDOW 123 0 0 Left 0
> WINDOW 39 24 132 Left 0
> SYMATTR SpiceLine Rser=0
> SYMATTR InstName V1
> SYMATTR Value 15
> SYMBOL res -336 32 R0
> WINDOW 3 -64 71 Left 0
> SYMATTR Value 2000
> SYMATTR InstName R2
> SYMBOL cap -208 336 R0
> SYMATTR InstName C2
> SYMATTR Value 0.01�f
> SYMBOL res -336 176 R0
> WINDOW 3 -60 41 Left 0
> SYMATTR Value 1500
> SYMATTR InstName R1
> SYMBOL ind 224 128 R0
> SYMATTR InstName L1
> SYMATTR Value 1mh
> SYMBOL schottky 336 112 R90
> WINDOW 0 0 32 VBottom 0
> WINDOW 3 32 32 VTop 0
> SYMATTR InstName D2
> SYMATTR Value 1N5819
> SYMATTR Description Diode
> SYMATTR Type diode
> SYMBOL cap 384 176 R0
> SYMATTR InstName C1
> SYMATTR Value .5�f
> SYMBOL res 192 -32 R90
> WINDOW 0 0 56 VBottom 0
> WINDOW 3 32 56 VTop 0
> SYMATTR InstName R3
> SYMATTR Value 1k
> SYMBOL pnp 176 32 M180
> SYMATTR InstName Q1
> SYMATTR Value BCW68F
> SYMBOL zener 704 160 R0
> SYMATTR InstName D1
> SYMATTR Value DFLZ33
> SYMATTR Description Diode
> SYMATTR Type diode
> SYMBOL npn 784 352 R180
> SYMATTR InstName Q2
> SYMATTR Value 2N3904
> SYMBOL res 608 240 R90
> WINDOW 0 0 56 VBottom 0
> WINDOW 3 32 56 VTop 0
> SYMATTR InstName R4
> SYMATTR Value 10k
> TEXT 416 408 Left 0 !.tran 0 0.010 0 1 startup

Yes, good old common base biasing. fits the bill ;)



From: miso on 1 Feb 2010 01:56
On Jan 30, 1:50 pm, Joerg <inva...(a)invalid.invalid> wrote:
> m...(a)sushi.com wrote:
> > On Jan 28, 9:27 pm, John Larkin
> > <jjSNIPlar...(a)highTHISlandtechnology.com> wrote:
> >> This afternoon we were talking with Phil Hobbs about an
> >> electro-optical thingie we're doing. The prime power is a +15 volt
> >> wall wart, and we need -30 internally to power some photodiodes and
> >> opamps and stuff, 30 mA maybe. Our design currently has a cute
> >> homebrew single-inductor flyback converter, which circuit I've posted
> >> here some time back. We are concerned about having such a potentially
> >> noisy gadget on the same small board with nanoamp signals.
>
> >> I proposed a different circuit: imagine eight opto-SSRs and two
> >> capacitors. A low frequency clock, 400 Hz maybe, switches 4 of them on
> >> and 4 off, alternately. The arrangement connects the two caps in
> >> parallel to the +15 supply, charging them up. Then it disconnects them
> >> and then restacks them in series such as to make -30 to ground. The
> >> low frequency and fairly soft switching edges should make this pretty
> >> quiet.
>
> >> Phil named this the Groucho Marx Generator.
>
> >> John
>
> > There is always the philosophical question as to just how big is an
> > inductor. If it is not shielded, well, it's influence can be felt way
> > beyond it's borders. If shielded, less so, but nothing is perfect.
>
> > Slapping caps on a rail with a soft charge is probably the right
> > approach, though you really don't have to get exotic here. You could
> > go to a tripler scheme if it is "on demand" so to speak (i.e.
> > regulated),  If the flying cap to reservoir is sized appropriately,
> > you can keep the step sizes small, then linearly regulate the output.
>
> > Here is a good question. How do they generate the phantom voltage in
> > battery powered microphone line amps. Surely they have the same
> > issues.
>
> The ones I came across are just an oscillator and a Cockcroft-Walton
> cascade, or with a little ferrite core transformer. Then there are the
> really crude "solutions" like a stack of 9V batteries (seriously ...).
>
> --
> Regards, Joerg
>
> http://www.analogconsultants.com/
>
> "gmail" domain blocked because of excessive spam.
> Use another domain or send PM.

http://en.wikipedia.org/wiki/Cockcroft%E2%80%93Walton_generator
Oh that circuit has a name? ;-) Thanks.
From: John Larkin on 1 Feb 2010 14:34
On Sun, 31 Jan 2010 16:30:19 -0800 (PST), MooseFET
<kensmith(a)rahul.net> wrote:

>On Jan 31, 3:03�pm, Jamie
><jamie_ka1lpa_not_valid_after_ka1l...(a)charter.net> wrote:
>> MooseFET wrote:
>> > On Jan 31, 7:29 am, Glen Walpert <nos...(a)null.void> wrote:
>>
>> >>On Sat, 30 Jan 2010 10:05:13 -0800, John Larkin wrote:
>>
>> >>>On Sat, 30 Jan 2010 09:58:57 -0600, mook Johnson <m...(a)mook.net> wrote:
>>
>
>If you want more efficient operation, you could do this:
>
>Version 4
>SHEET 1 880 680
>WIRE 240 -80 64 -80
>WIRE 240 -64 240 -80
>WIRE -320 -48 -448 -48
>WIRE 64 -48 64 -80
>WIRE 64 -48 -320 -48
>WIRE 96 -16 80 -16
>WIRE -320 48 -320 -48
>WIRE -320 64 -320 48
>WIRE -160 128 -320 128
>WIRE 80 128 80 -16
>WIRE 80 128 64 128
>WIRE 240 128 240 32
>WIRE 272 128 240 128
>WIRE 400 128 336 128
>WIRE 720 128 400 128
>WIRE 240 144 240 128
>WIRE 720 160 720 128
>WIRE 400 176 400 128
>WIRE -320 192 -320 128
>WIRE -160 192 -320 192
>WIRE 144 192 64 192
>WIRE -448 256 -448 -48
>WIRE -416 256 -448 256
>WIRE -160 256 -416 256
>WIRE 96 256 64 256
>WIRE 240 256 240 224
>WIRE 240 256 96 256
>WIRE 400 256 400 240
>WIRE 400 256 240 256
>WIRE 512 256 400 256
>WIRE 720 256 720 224
>WIRE 720 256 592 256
>WIRE 96 288 96 256
>WIRE -416 304 -416 256
>WIRE 848 304 784 304
>WIRE -320 320 -320 272
>WIRE -192 320 -320 320
>WIRE 144 320 144 192
>WIRE 144 320 -192 320
>WIRE -320 336 -320 320
>WIRE -192 336 -192 320
>WIRE 720 352 400 352
>WIRE 144 368 144 320
>WIRE 400 368 400 352
>WIRE 400 368 144 368
>WIRE -416 400 -416 384
>WIRE -192 400 -320 400
>FLAG 96 288 0
>FLAG -416 400 0
>FLAG -320 400 0
>FLAG 848 304 0
>SYMBOL Misc\\NE555 -48 160 R180
>SYMATTR InstName U1
>SYMBOL voltage -416 288 R0
>WINDOW 123 0 0 Left 0
>WINDOW 39 24 132 Left 0
>SYMATTR SpiceLine Rser=0
>SYMATTR InstName V1
>SYMATTR Value 15
>SYMBOL res -336 32 R0
>WINDOW 3 -64 71 Left 0
>SYMATTR Value 2000
>SYMATTR InstName R2
>SYMBOL cap -208 336 R0
>SYMATTR InstName C2
>SYMATTR Value 0.01?f
>SYMBOL res -336 176 R0
>WINDOW 3 -60 41 Left 0
>SYMATTR Value 1500
>SYMATTR InstName R1
>SYMBOL ind 224 128 R0
>SYMATTR InstName L1
>SYMATTR Value 1mh
>SYMBOL schottky 336 112 R90
>WINDOW 0 0 32 VBottom 0
>WINDOW 3 32 32 VTop 0
>SYMATTR InstName D2
>SYMATTR Value 1N5819
>SYMATTR Description Diode
>SYMATTR Type diode
>SYMBOL cap 384 176 R0
>SYMATTR InstName C1
>SYMATTR Value .5?f
>SYMBOL res 192 -32 R90
>WINDOW 0 0 56 VBottom 0
>WINDOW 3 32 56 VTop 0
>SYMATTR InstName R3
>SYMATTR Value 1k
>SYMBOL pnp 176 32 M180
>SYMATTR InstName Q1
>SYMATTR Value BCW68F
>SYMBOL zener 704 160 R0
>SYMATTR InstName D1
>SYMATTR Value DFLZ33
>SYMATTR Description Diode
>SYMATTR Type diode
>SYMBOL npn 784 352 R180
>SYMATTR InstName Q2
>SYMATTR Value 2N3904
>SYMBOL res 608 240 R90
>WINDOW 0 0 56 VBottom 0
>WINDOW 3 32 56 VTop 0
>SYMATTR InstName R4
>SYMATTR Value 10k
>TEXT 416 408 Left 0 !.tran 0 0.010 0 1 startup



Here's my inverter, sort of similar.

ftp://jjlarkin.lmi.net/Inverter.jpg

The thevenin impedance seen by the emitter determines loop gain. I
needed the ESR of the tantalum in the output to get good loop
stability; startup dV/dT is low enough that a tantalum appears safe
here.

Load regulation is surprisingly good, about a tenth of a volt from 80
to 500 mA.

John



From: miso on 1 Feb 2010 23:43
On Feb 1, 11:34 am, John Larkin
<jjlar...(a)highNOTlandTHIStechnologyPART.com> wrote:
> On Sun, 31 Jan 2010 16:30:19 -0800 (PST), MooseFET
>
>
>
> <kensm...(a)rahul.net> wrote:
> >On Jan 31, 3:03 pm, Jamie
> ><jamie_ka1lpa_not_valid_after_ka1l...(a)charter.net> wrote:
> >> MooseFET wrote:
> >> > On Jan 31, 7:29 am, Glen Walpert <nos...(a)null.void> wrote:
>
> >> >>On Sat, 30 Jan 2010 10:05:13 -0800, John Larkin wrote:
>
> >> >>>On Sat, 30 Jan 2010 09:58:57 -0600, mook Johnson <m...(a)mook.net> wrote:
>
> >If you want more efficient operation, you could do this:
>
> >Version 4
> >SHEET 1 880 680
> >WIRE 240 -80 64 -80
> >WIRE 240 -64 240 -80
> >WIRE -320 -48 -448 -48
> >WIRE 64 -48 64 -80
> >WIRE 64 -48 -320 -48
> >WIRE 96 -16 80 -16
> >WIRE -320 48 -320 -48
> >WIRE -320 64 -320 48
> >WIRE -160 128 -320 128
> >WIRE 80 128 80 -16
> >WIRE 80 128 64 128
> >WIRE 240 128 240 32
> >WIRE 272 128 240 128
> >WIRE 400 128 336 128
> >WIRE 720 128 400 128
> >WIRE 240 144 240 128
> >WIRE 720 160 720 128
> >WIRE 400 176 400 128
> >WIRE -320 192 -320 128
> >WIRE -160 192 -320 192
> >WIRE 144 192 64 192
> >WIRE -448 256 -448 -48
> >WIRE -416 256 -448 256
> >WIRE -160 256 -416 256
> >WIRE 96 256 64 256
> >WIRE 240 256 240 224
> >WIRE 240 256 96 256
> >WIRE 400 256 400 240
> >WIRE 400 256 240 256
> >WIRE 512 256 400 256
> >WIRE 720 256 720 224
> >WIRE 720 256 592 256
> >WIRE 96 288 96 256
> >WIRE -416 304 -416 256
> >WIRE 848 304 784 304
> >WIRE -320 320 -320 272
> >WIRE -192 320 -320 320
> >WIRE 144 320 144 192
> >WIRE 144 320 -192 320
> >WIRE -320 336 -320 320
> >WIRE -192 336 -192 320
> >WIRE 720 352 400 352
> >WIRE 144 368 144 320
> >WIRE 400 368 400 352
> >WIRE 400 368 144 368
> >WIRE -416 400 -416 384
> >WIRE -192 400 -320 400
> >FLAG 96 288 0
> >FLAG -416 400 0
> >FLAG -320 400 0
> >FLAG 848 304 0
> >SYMBOL Misc\\NE555 -48 160 R180
> >SYMATTR InstName U1
> >SYMBOL voltage -416 288 R0
> >WINDOW 123 0 0 Left 0
> >WINDOW 39 24 132 Left 0
> >SYMATTR SpiceLine Rser=0
> >SYMATTR InstName V1
> >SYMATTR Value 15
> >SYMBOL res -336 32 R0
> >WINDOW 3 -64 71 Left 0
> >SYMATTR Value 2000
> >SYMATTR InstName R2
> >SYMBOL cap -208 336 R0
> >SYMATTR InstName C2
> >SYMATTR Value 0.01?f
> >SYMBOL res -336 176 R0
> >WINDOW 3 -60 41 Left 0
> >SYMATTR Value 1500
> >SYMATTR InstName R1
> >SYMBOL ind 224 128 R0
> >SYMATTR InstName L1
> >SYMATTR Value 1mh
> >SYMBOL schottky 336 112 R90
> >WINDOW 0 0 32 VBottom 0
> >WINDOW 3 32 32 VTop 0
> >SYMATTR InstName D2
> >SYMATTR Value 1N5819
> >SYMATTR Description Diode
> >SYMATTR Type diode
> >SYMBOL cap 384 176 R0
> >SYMATTR InstName C1
> >SYMATTR Value .5?f
> >SYMBOL res 192 -32 R90
> >WINDOW 0 0 56 VBottom 0
> >WINDOW 3 32 56 VTop 0
> >SYMATTR InstName R3
> >SYMATTR Value 1k
> >SYMBOL pnp 176 32 M180
> >SYMATTR InstName Q1
> >SYMATTR Value BCW68F
> >SYMBOL zener 704 160 R0
> >SYMATTR InstName D1
> >SYMATTR Value DFLZ33
> >SYMATTR Description Diode
> >SYMATTR Type diode
> >SYMBOL npn 784 352 R180
> >SYMATTR InstName Q2
> >SYMATTR Value 2N3904
> >SYMBOL res 608 240 R90
> >WINDOW 0 0 56 VBottom 0
> >WINDOW 3 32 56 VTop 0
> >SYMATTR InstName R4
> >SYMATTR Value 10k
> >TEXT 416 408 Left 0 !.tran 0 0.010 0 1 startup
>
> Here's my inverter, sort of similar.
>
> ftp://jjlarkin.lmi.net/Inverter.jpg
>
> The thevenin impedance seen by the emitter determines loop gain. I
> needed the ESR of the tantalum in the output to get good loop
> stability; startup dV/dT is low enough that a tantalum appears safe
> here.
>
> Load regulation is surprisingly good, about a tenth of a volt from 80
> to 500 mA.
>
> John

I see a start up problem here. Look at the UVL of the LM5112. Won't
this circuit whack the inductor while starting up?

From: John Larkin on 2 Feb 2010 00:00
On Mon, 1 Feb 2010 20:43:39 -0800 (PST), "miso(a)sushi.com"
<miso(a)sushi.com> wrote:

>On Feb 1, 11:34�am, John Larkin
><jjlar...(a)highNOTlandTHIStechnologyPART.com> wrote:
>> On Sun, 31 Jan 2010 16:30:19 -0800 (PST), MooseFET
>>
>>
>>
>> <kensm...(a)rahul.net> wrote:
>> >On Jan 31, 3:03�pm, Jamie
>> ><jamie_ka1lpa_not_valid_after_ka1l...(a)charter.net> wrote:
>> >> MooseFET wrote:
>> >> > On Jan 31, 7:29 am, Glen Walpert <nos...(a)null.void> wrote:
>>
>> >> >>On Sat, 30 Jan 2010 10:05:13 -0800, John Larkin wrote:
>>
>> >> >>>On Sat, 30 Jan 2010 09:58:57 -0600, mook Johnson <m...(a)mook.net> wrote:
>>
>> >If you want more efficient operation, you could do this:
>>
>> >Version 4
>> >SHEET 1 880 680
>> >WIRE 240 -80 64 -80
>> >WIRE 240 -64 240 -80
>> >WIRE -320 -48 -448 -48
>> >WIRE 64 -48 64 -80
>> >WIRE 64 -48 -320 -48
>> >WIRE 96 -16 80 -16
>> >WIRE -320 48 -320 -48
>> >WIRE -320 64 -320 48
>> >WIRE -160 128 -320 128
>> >WIRE 80 128 80 -16
>> >WIRE 80 128 64 128
>> >WIRE 240 128 240 32
>> >WIRE 272 128 240 128
>> >WIRE 400 128 336 128
>> >WIRE 720 128 400 128
>> >WIRE 240 144 240 128
>> >WIRE 720 160 720 128
>> >WIRE 400 176 400 128
>> >WIRE -320 192 -320 128
>> >WIRE -160 192 -320 192
>> >WIRE 144 192 64 192
>> >WIRE -448 256 -448 -48
>> >WIRE -416 256 -448 256
>> >WIRE -160 256 -416 256
>> >WIRE 96 256 64 256
>> >WIRE 240 256 240 224
>> >WIRE 240 256 96 256
>> >WIRE 400 256 400 240
>> >WIRE 400 256 240 256
>> >WIRE 512 256 400 256
>> >WIRE 720 256 720 224
>> >WIRE 720 256 592 256
>> >WIRE 96 288 96 256
>> >WIRE -416 304 -416 256
>> >WIRE 848 304 784 304
>> >WIRE -320 320 -320 272
>> >WIRE -192 320 -320 320
>> >WIRE 144 320 144 192
>> >WIRE 144 320 -192 320
>> >WIRE -320 336 -320 320
>> >WIRE -192 336 -192 320
>> >WIRE 720 352 400 352
>> >WIRE 144 368 144 320
>> >WIRE 400 368 400 352
>> >WIRE 400 368 144 368
>> >WIRE -416 400 -416 384
>> >WIRE -192 400 -320 400
>> >FLAG 96 288 0
>> >FLAG -416 400 0
>> >FLAG -320 400 0
>> >FLAG 848 304 0
>> >SYMBOL Misc\\NE555 -48 160 R180
>> >SYMATTR InstName U1
>> >SYMBOL voltage -416 288 R0
>> >WINDOW 123 0 0 Left 0
>> >WINDOW 39 24 132 Left 0
>> >SYMATTR SpiceLine Rser=0
>> >SYMATTR InstName V1
>> >SYMATTR Value 15
>> >SYMBOL res -336 32 R0
>> >WINDOW 3 -64 71 Left 0
>> >SYMATTR Value 2000
>> >SYMATTR InstName R2
>> >SYMBOL cap -208 336 R0
>> >SYMATTR InstName C2
>> >SYMATTR Value 0.01?f
>> >SYMBOL res -336 176 R0
>> >WINDOW 3 -60 41 Left 0
>> >SYMATTR Value 1500
>> >SYMATTR InstName R1
>> >SYMBOL ind 224 128 R0
>> >SYMATTR InstName L1
>> >SYMATTR Value 1mh
>> >SYMBOL schottky 336 112 R90
>> >WINDOW 0 0 32 VBottom 0
>> >WINDOW 3 32 32 VTop 0
>> >SYMATTR InstName D2
>> >SYMATTR Value 1N5819
>> >SYMATTR Description Diode
>> >SYMATTR Type diode
>> >SYMBOL cap 384 176 R0
>> >SYMATTR InstName C1
>> >SYMATTR Value .5?f
>> >SYMBOL res 192 -32 R90
>> >WINDOW 0 0 56 VBottom 0
>> >WINDOW 3 32 56 VTop 0
>> >SYMATTR InstName R3
>> >SYMATTR Value 1k
>> >SYMBOL pnp 176 32 M180
>> >SYMATTR InstName Q1
>> >SYMATTR Value BCW68F
>> >SYMBOL zener 704 160 R0
>> >SYMATTR InstName D1
>> >SYMATTR Value DFLZ33
>> >SYMATTR Description Diode
>> >SYMATTR Type diode
>> >SYMBOL npn 784 352 R180
>> >SYMATTR InstName Q2
>> >SYMATTR Value 2N3904
>> >SYMBOL res 608 240 R90
>> >WINDOW 0 0 56 VBottom 0
>> >WINDOW 3 32 56 VTop 0
>> >SYMATTR InstName R4
>> >SYMATTR Value 10k
>> >TEXT 416 408 Left 0 !.tran 0 0.010 0 1 startup
>>
>> Here's my inverter, sort of similar.
>>
>> ftp://jjlarkin.lmi.net/Inverter.jpg
>>
>> The thevenin impedance seen by the emitter determines loop gain. I
>> needed the ESR of the tantalum in the output to get good loop
>> stability; startup dV/dT is low enough that a tantalum appears safe
>> here.
>>
>> Load regulation is surprisingly good, about a tenth of a volt from 80
>> to 500 mA.
>>
>> John
>
>I see a start up problem here. Look at the UVL of the LM5112. Won't
>this circuit whack the inductor while starting up?

It's designed to start up at about 70% duty cycle. When the output
gets close to -12, the transistor turns on and backs off the duty
cycle to whatever it needs, which should be a bit over 50%.

John



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