Forums

what I would use for a low current 100Volt supply.

Started by Jamie September 28, 2011
This is my contributions to the already going thread on a 100 volt
capable DC-DC buck boost using a 555 and a zener for regulation that
uses the minimum parts. I don't even have a timing cap in there.

  Set R1 for the Max I you need as the load and the zener will suck
up what you don't use to maintain a constant voltage.. Of course this
type of boost is only good if your load constraints are not all over the
place.

  Replace R1 with a PNP current sink that can be reversed bias with a 
feed back regulator and you can have a large output unit with low stand 
by current, instead if using a Zener like I do with low current demands

Version 4
SHEET 1 880 680
WIRE -128 -80 -256 -80
WIRE -112 -80 -128 -80
WIRE 320 -80 -112 -80
WIRE -256 -48 -256 -80
WIRE 432 -32 0 -32
WIRE -112 32 -112 -80
WIRE 320 64 320 -80
WIRE 320 64 304 64
WIRE 336 64 320 64
WIRE 432 64 432 -32
WIRE 432 64 416 64
WIRE 464 64 432 64
WIRE 464 96 464 64
WIRE -112 128 -112 112
WIRE -112 128 -208 128
WIRE 0 128 0 -32
WIRE 80 128 0 128
WIRE -112 144 -112 128
WIRE -32 192 -48 192
WIRE 80 192 48 192
WIRE 432 192 432 64
WIRE 432 192 304 192
WIRE 464 192 464 176
WIRE 528 192 464 192
WIRE 608 192 592 192
WIRE 464 208 464 192
WIRE 608 208 608 192
WIRE -112 256 -112 240
WIRE 80 256 64 256
WIRE 400 256 384 256
WIRE -208 320 -208 128
WIRE 384 320 384 256
WIRE 384 320 -208 320
WIRE 464 320 464 304
WIRE 608 320 608 272
FLAG -256 32 0
FLAG 80 64 0
FLAG 608 320 0
FLAG -128 -80 P+
FLAG 64 256 P+
FLAG 464 320 0
FLAG -112 256 0
SYMBOL Misc\\NE555 192 160 R0
SYMATTR InstName U1
SYMBOL voltage -256 -64 R0
WINDOW 123 0 0 Left 2
WINDOW 39 0 0 Left 2
SYMATTR InstName V1
SYMATTR Value 10
SYMBOL res 432 48 R90
WINDOW 0 0 56 VBottom 2
WINDOW 3 32 56 VTop 2
SYMATTR InstName R1
SYMATTR Value 250
SYMBOL ind 448 80 R0
SYMATTR InstName L1
SYMATTR Value 1mh
SYMATTR SpiceLine Rser=0.1
SYMBOL zener 528 208 R270
WINDOW 0 32 32 VTop 2
WINDOW 3 52 118 VBottom 2
SYMATTR InstName D1
SYMATTR Value DFLZ33
SYMATTR Description Diode
SYMATTR Type diode
SYMBOL cap 592 208 R0
SYMATTR InstName C1
SYMATTR Value 1�f
SYMBOL npn 400 208 R0
SYMATTR InstName Q1
SYMATTR Value 2N5550
SYMBOL npn -48 144 M0
SYMATTR InstName Q2
SYMBOL res 64 176 R90
WINDOW 0 0 56 VBottom 2
WINDOW 3 32 56 VTop 2
SYMATTR InstName R3
SYMATTR Value 1200
SYMBOL res -128 16 R0
SYMATTR InstName R4
SYMATTR Value 1200
TEXT -240 360 Left 0 !.tran 0 0.010 0 0.01 startup

Jamie



On Wed, 28 Sep 2011 20:55:03 -0400, Jamie
<jamie_ka1lpa_not_valid_after_ka1lpa_@charter.net> wrote:

>This is my contributions to the already going thread on a 100 volt >capable DC-DC buck boost using a 555 and a zener for regulation that >uses the minimum parts. I don't even have a timing cap in there. > > Set R1 for the Max I you need as the load and the zener will suck >up what you don't use to maintain a constant voltage.. Of course this >type of boost is only good if your load constraints are not all over the >place. > > Replace R1 with a PNP current sink that can be reversed bias with a >feed back regulator and you can have a large output unit with low stand >by current, instead if using a Zener like I do with low current demands > >Version 4 >SHEET 1 880 680 >WIRE -128 -80 -256 -80 >WIRE -112 -80 -128 -80 >WIRE 320 -80 -112 -80 >WIRE -256 -48 -256 -80 >WIRE 432 -32 0 -32 >WIRE -112 32 -112 -80 >WIRE 320 64 320 -80 >WIRE 320 64 304 64 >WIRE 336 64 320 64 >WIRE 432 64 432 -32 >WIRE 432 64 416 64 >WIRE 464 64 432 64 >WIRE 464 96 464 64 >WIRE -112 128 -112 112 >WIRE -112 128 -208 128 >WIRE 0 128 0 -32 >WIRE 80 128 0 128 >WIRE -112 144 -112 128 >WIRE -32 192 -48 192 >WIRE 80 192 48 192 >WIRE 432 192 432 64 >WIRE 432 192 304 192 >WIRE 464 192 464 176 >WIRE 528 192 464 192 >WIRE 608 192 592 192 >WIRE 464 208 464 192 >WIRE 608 208 608 192 >WIRE -112 256 -112 240 >WIRE 80 256 64 256 >WIRE 400 256 384 256 >WIRE -208 320 -208 128 >WIRE 384 320 384 256 >WIRE 384 320 -208 320 >WIRE 464 320 464 304 >WIRE 608 320 608 272 >FLAG -256 32 0 >FLAG 80 64 0 >FLAG 608 320 0 >FLAG -128 -80 P+ >FLAG 64 256 P+ >FLAG 464 320 0 >FLAG -112 256 0 >SYMBOL Misc\\NE555 192 160 R0 >SYMATTR InstName U1 >SYMBOL voltage -256 -64 R0 >WINDOW 123 0 0 Left 2 >WINDOW 39 0 0 Left 2 >SYMATTR InstName V1 >SYMATTR Value 10 >SYMBOL res 432 48 R90 >WINDOW 0 0 56 VBottom 2 >WINDOW 3 32 56 VTop 2 >SYMATTR InstName R1 >SYMATTR Value 250 >SYMBOL ind 448 80 R0 >SYMATTR InstName L1 >SYMATTR Value 1mh >SYMATTR SpiceLine Rser=0.1 >SYMBOL zener 528 208 R270 >WINDOW 0 32 32 VTop 2 >WINDOW 3 52 118 VBottom 2 >SYMATTR InstName D1 >SYMATTR Value DFLZ33 >SYMATTR Description Diode >SYMATTR Type diode >SYMBOL cap 592 208 R0 >SYMATTR InstName C1 >SYMATTR Value 1&#2013266101;f >SYMBOL npn 400 208 R0 >SYMATTR InstName Q1 >SYMATTR Value 2N5550 >SYMBOL npn -48 144 M0 >SYMATTR InstName Q2 >SYMBOL res 64 176 R90 >WINDOW 0 0 56 VBottom 2 >WINDOW 3 32 56 VTop 2 >SYMATTR InstName R3 >SYMATTR Value 1200 >SYMBOL res -128 16 R0 >SYMATTR InstName R4 >SYMATTR Value 1200 >TEXT -240 360 Left 0 !.tran 0 0.010 0 0.01 startup > >Jamie > >
That's cute. It's hysteretic on inductor current, and D1 pushes current into the cap, then steals it back again. It will compete with my circuit for the Miss Inefficiency title. John
On a sunny day (Wed, 28 Sep 2011 20:55:03 -0400) it happened Jamie
<jamie_ka1lpa_not_valid_after_ka1lpa_@charter.net> wrote in
<t9Pgq.8$Gb4.5@newsfe08.iad>:

>This is my contributions to the already going thread on a 100 volt >capable DC-DC buck boost using a 555 and a zener for regulation that >uses the minimum parts. I don't even have a timing cap in there. > > Set R1 for the Max I you need as the load and the zener will suck >up what you don't use to maintain a constant voltage.. Of course this >type of boost is only good if your load constraints are not all over the >place. > > Replace R1 with a PNP current sink that can be reversed bias with a >feed back regulator and you can have a large output unit with low stand >by current, instead if using a Zener like I do with low current demands > >Version 4 >SHEET 1 880 680 >WIRE -128 -80 -256 -80 >WIRE -112 -80 -128 -80 >WIRE 320 -80 -112 -80 >WIRE -256 -48 -256 -80 >WIRE 432 -32 0 -32 >WIRE -112 32 -112 -80 >WIRE 320 64 320 -80 >WIRE 320 64 304 64 >WIRE 336 64 320 64 >WIRE 432 64 432 -32 >WIRE 432 64 416 64 >WIRE 464 64 432 64 >WIRE 464 96 464 64 >WIRE -112 128 -112 112 >WIRE -112 128 -208 128 >WIRE 0 128 0 -32 >WIRE 80 128 0 128 >WIRE -112 144 -112 128 >WIRE -32 192 -48 192 >WIRE 80 192 48 192 >WIRE 432 192 432 64 >WIRE 432 192 304 192 >WIRE 464 192 464 176 >WIRE 528 192 464 192 >WIRE 608 192 592 192 >WIRE 464 208 464 192 >WIRE 608 208 608 192 >WIRE -112 256 -112 240 >WIRE 80 256 64 256 >WIRE 400 256 384 256 >WIRE -208 320 -208 128 >WIRE 384 320 384 256 >WIRE 384 320 -208 320 >WIRE 464 320 464 304 >WIRE 608 320 608 272 >FLAG -256 32 0 >FLAG 80 64 0 >FLAG 608 320 0 >FLAG -128 -80 P+ >FLAG 64 256 P+ >FLAG 464 320 0 >FLAG -112 256 0 >SYMBOL Misc\\NE555 192 160 R0 >SYMATTR InstName U1 >SYMBOL voltage -256 -64 R0 >WINDOW 123 0 0 Left 2 >WINDOW 39 0 0 Left 2 >SYMATTR InstName V1 >SYMATTR Value 10 >SYMBOL res 432 48 R90 >WINDOW 0 0 56 VBottom 2 >WINDOW 3 32 56 VTop 2 >SYMATTR InstName R1 >SYMATTR Value 250 >SYMBOL ind 448 80 R0 >SYMATTR InstName L1 >SYMATTR Value 1mh >SYMATTR SpiceLine Rser=0.1 >SYMBOL zener 528 208 R270 >WINDOW 0 32 32 VTop 2 >WINDOW 3 52 118 VBottom 2 >SYMATTR InstName D1 >SYMATTR Value DFLZ33 >SYMATTR Description Diode >SYMATTR Type diode >SYMBOL cap 592 208 R0 >SYMATTR InstName C1 >SYMATTR Value 1&#2013266101;f >SYMBOL npn 400 208 R0 >SYMATTR InstName Q1 >SYMATTR Value 2N5550 >SYMBOL npn -48 144 M0 >SYMATTR InstName Q2 >SYMBOL res 64 176 R90 >WINDOW 0 0 56 VBottom 2 >WINDOW 3 32 56 VTop 2 >SYMATTR InstName R3 >SYMATTR Value 1200 >SYMBOL res -128 16 R0 >SYMATTR InstName R4 >SYMATTR Value 1200 >TEXT -240 360 Left 0 !.tran 0 0.010 0 0.01 startup > >Jamie
It is nice, can it be done without the inverter transistor?
"Jamie" <jamie_ka1lpa_not_valid_after_ka1lpa_@charter.net> schreef in 
bericht news:t9Pgq.8$Gb4.5@newsfe08.iad...
> This is my contributions to the already going thread on a 100 volt > capable DC-DC buck boost using a 555 and a zener for regulation that > uses the minimum parts. I don't even have a timing cap in there. > > Set R1 for the Max I you need as the load and the zener will suck > up what you don't use to maintain a constant voltage.. Of course this > type of boost is only good if your load constraints are not all over the > place. > > Replace R1 with a PNP current sink that can be reversed bias with a feed > back regulator and you can have a large output unit with low stand by > current, instead if using a Zener like I do with low current demands > > Version 4 > SHEET 1 880 680 > WIRE -128 -80 -256 -80 > WIRE -112 -80 -128 -80 > WIRE 320 -80 -112 -80 > WIRE -256 -48 -256 -80 > WIRE 432 -32 0 -32 > WIRE -112 32 -112 -80 > WIRE 320 64 320 -80 > WIRE 320 64 304 64 > WIRE 336 64 320 64 > WIRE 432 64 432 -32 > WIRE 432 64 416 64 > WIRE 464 64 432 64 > WIRE 464 96 464 64 > WIRE -112 128 -112 112 > WIRE -112 128 -208 128 > WIRE 0 128 0 -32 > WIRE 80 128 0 128 > WIRE -112 144 -112 128 > WIRE -32 192 -48 192 > WIRE 80 192 48 192 > WIRE 432 192 432 64 > WIRE 432 192 304 192 > WIRE 464 192 464 176 > WIRE 528 192 464 192 > WIRE 608 192 592 192 > WIRE 464 208 464 192 > WIRE 608 208 608 192 > WIRE -112 256 -112 240 > WIRE 80 256 64 256 > WIRE 400 256 384 256 > WIRE -208 320 -208 128 > WIRE 384 320 384 256 > WIRE 384 320 -208 320 > WIRE 464 320 464 304 > WIRE 608 320 608 272 > FLAG -256 32 0 > FLAG 80 64 0 > FLAG 608 320 0 > FLAG -128 -80 P+ > FLAG 64 256 P+ > FLAG 464 320 0 > FLAG -112 256 0 > SYMBOL Misc\\NE555 192 160 R0 > SYMATTR InstName U1 > SYMBOL voltage -256 -64 R0 > WINDOW 123 0 0 Left 2 > WINDOW 39 0 0 Left 2 > SYMATTR InstName V1 > SYMATTR Value 10 > SYMBOL res 432 48 R90 > WINDOW 0 0 56 VBottom 2 > WINDOW 3 32 56 VTop 2 > SYMATTR InstName R1 > SYMATTR Value 250 > SYMBOL ind 448 80 R0 > SYMATTR InstName L1 > SYMATTR Value 1mh > SYMATTR SpiceLine Rser=0.1 > SYMBOL zener 528 208 R270 > WINDOW 0 32 32 VTop 2 > WINDOW 3 52 118 VBottom 2 > SYMATTR InstName D1 > SYMATTR Value DFLZ33 > SYMATTR Description Diode > SYMATTR Type diode > SYMBOL cap 592 208 R0 > SYMATTR InstName C1 > SYMATTR Value 1&#2013266101;f > SYMBOL npn 400 208 R0 > SYMATTR InstName Q1 > SYMATTR Value 2N5550 > SYMBOL npn -48 144 M0 > SYMATTR InstName Q2 > SYMBOL res 64 176 R90 > WINDOW 0 0 56 VBottom 2 > WINDOW 3 32 56 VTop 2 > SYMATTR InstName R3 > SYMATTR Value 1200 > SYMBOL res -128 16 R0 > SYMATTR InstName R4 > SYMATTR Value 1200 > TEXT -240 360 Left 0 !.tran 0 0.010 0 0.01 startup > > Jamie > > >
It's not clear to me what current you need but the voltage does not even comes close to the 100V you say you want to achieve and that's without load. If you really want 100V with some mA you better go for an old MC34063. It's not state of the art and has some drawbacks but you'll get what you want. petrus bitbyter
On a sunny day (Thu, 29 Sep 2011 13:31:11 +0200) it happened "petrus bitbyter"
<petrus.bitbyter@hotmail.com> wrote in
<4e8456ff$0$5612$e4fe514c@dreader31.news.xs4all.nl>:

>If you really want 100V with some mA you better go for an old MC34063. It's >not state of the art and has some drawbacks but you'll get what you want.
Nope: http://forum.pololu.com/viewtopic.php?t=1453
Jamie <jamie_ka1lpa_not_valid_after_ka1lpa_@charter.net> wrote:

>This is my contributions to the already going thread on a 100 volt >capable DC-DC buck boost using a 555 and a zener for regulation that >uses the minimum parts. I don't even have a timing cap in there. > > Set R1 for the Max I you need as the load and the zener will suck >up what you don't use to maintain a constant voltage.. Of course this >type of boost is only good if your load constraints are not all over the >place.
In the past I've used the NE555 several times for these sort of step-up converters. Its works well and doesn't need -to quote Joerg- boutique parts. At a point one of my former employers was so short on money I had to design a step-up converter from parts that where on stock. Well... that included an NE555. -- Failure does not prove something is impossible, failure simply indicates you are not using the right tools... nico@nctdevpuntnl (punt=.) --------------------------------------------------------------
Jan Panteltje wrote:

> On a sunny day (Wed, 28 Sep 2011 20:55:03 -0400) it happened Jamie > <jamie_ka1lpa_not_valid_after_ka1lpa_@charter.net> wrote in > <t9Pgq.8$Gb4.5@newsfe08.iad>: > > >>This is my contributions to the already going thread on a 100 volt >>capable DC-DC buck boost using a 555 and a zener for regulation that >>uses the minimum parts. I don't even have a timing cap in there. >> >> Set R1 for the Max I you need as the load and the zener will suck >>up what you don't use to maintain a constant voltage.. Of course this >>type of boost is only good if your load constraints are not all over the >>place. >> >> Replace R1 with a PNP current sink that can be reversed bias with a >>feed back regulator and you can have a large output unit with low stand >>by current, instead if using a Zener like I do with low current demands >> >>Version 4 >>SHEET 1 880 680 >>WIRE -128 -80 -256 -80 >>WIRE -112 -80 -128 -80 >>WIRE 320 -80 -112 -80 >>WIRE -256 -48 -256 -80 >>WIRE 432 -32 0 -32 >>WIRE -112 32 -112 -80 >>WIRE 320 64 320 -80 >>WIRE 320 64 304 64 >>WIRE 336 64 320 64 >>WIRE 432 64 432 -32 >>WIRE 432 64 416 64 >>WIRE 464 64 432 64 >>WIRE 464 96 464 64 >>WIRE -112 128 -112 112 >>WIRE -112 128 -208 128 >>WIRE 0 128 0 -32 >>WIRE 80 128 0 128 >>WIRE -112 144 -112 128 >>WIRE -32 192 -48 192 >>WIRE 80 192 48 192 >>WIRE 432 192 432 64 >>WIRE 432 192 304 192 >>WIRE 464 192 464 176 >>WIRE 528 192 464 192 >>WIRE 608 192 592 192 >>WIRE 464 208 464 192 >>WIRE 608 208 608 192 >>WIRE -112 256 -112 240 >>WIRE 80 256 64 256 >>WIRE 400 256 384 256 >>WIRE -208 320 -208 128 >>WIRE 384 320 384 256 >>WIRE 384 320 -208 320 >>WIRE 464 320 464 304 >>WIRE 608 320 608 272 >>FLAG -256 32 0 >>FLAG 80 64 0 >>FLAG 608 320 0 >>FLAG -128 -80 P+ >>FLAG 64 256 P+ >>FLAG 464 320 0 >>FLAG -112 256 0 >>SYMBOL Misc\\NE555 192 160 R0 >>SYMATTR InstName U1 >>SYMBOL voltage -256 -64 R0 >>WINDOW 123 0 0 Left 2 >>WINDOW 39 0 0 Left 2 >>SYMATTR InstName V1 >>SYMATTR Value 10 >>SYMBOL res 432 48 R90 >>WINDOW 0 0 56 VBottom 2 >>WINDOW 3 32 56 VTop 2 >>SYMATTR InstName R1 >>SYMATTR Value 250 >>SYMBOL ind 448 80 R0 >>SYMATTR InstName L1 >>SYMATTR Value 1mh >>SYMATTR SpiceLine Rser=0.1 >>SYMBOL zener 528 208 R270 >>WINDOW 0 32 32 VTop 2 >>WINDOW 3 52 118 VBottom 2 >>SYMATTR InstName D1 >>SYMATTR Value DFLZ33 >>SYMATTR Description Diode >>SYMATTR Type diode >>SYMBOL cap 592 208 R0 >>SYMATTR InstName C1 >>SYMATTR Value 1&#2013266101;f >>SYMBOL npn 400 208 R0 >>SYMATTR InstName Q1 >>SYMATTR Value 2N5550 >>SYMBOL npn -48 144 M0 >>SYMATTR InstName Q2 >>SYMBOL res 64 176 R90 >>WINDOW 0 0 56 VBottom 2 >>WINDOW 3 32 56 VTop 2 >>SYMATTR InstName R3 >>SYMATTR Value 1200 >>SYMBOL res -128 16 R0 >>SYMATTR InstName R4 >>SYMATTR Value 1200 >>TEXT -240 360 Left 0 !.tran 0 0.010 0 0.01 startup >> >>Jamie > > > It is nice, can it be done without the inverter transistor?
I did that because it needed to be inverted, as you can see. If you were looking for a (-) output then the circuit could be altered and yes, only one transistor is needed, since then, you'd be using a PNP on the top side and the output of the timer would not need to be inverted. Using a P-channel mosfet as an follower instead sounds attractive how ever, it'll just drop into linear mode when the output on the source gets to the point where there isn't enough gate voltage from the timer. I've done this also with a dual comparator (8 pin package) and set up a window trigger and threshold, like the timer is. With that, you can simply alter the inputs that are used and you only need one transistor on the buck switch. It's just with a timer, the parts count is low and it has a hefty output. :) Something to think about I guess :) Jamie
petrus bitbyter wrote:
> "Jamie" <jamie_ka1lpa_not_valid_after_ka1lpa_@charter.net> schreef in > bericht news:t9Pgq.8$Gb4.5@newsfe08.iad... > >>This is my contributions to the already going thread on a 100 volt >>capable DC-DC buck boost using a 555 and a zener for regulation that >>uses the minimum parts. I don't even have a timing cap in there. >> >> Set R1 for the Max I you need as the load and the zener will suck >>up what you don't use to maintain a constant voltage.. Of course this >>type of boost is only good if your load constraints are not all over the >>place. >> >> Replace R1 with a PNP current sink that can be reversed bias with a feed >>back regulator and you can have a large output unit with low stand by >>current, instead if using a Zener like I do with low current demands >> >>Version 4 >>SHEET 1 880 680 >>WIRE -128 -80 -256 -80 >>WIRE -112 -80 -128 -80 >>WIRE 320 -80 -112 -80 >>WIRE -256 -48 -256 -80 >>WIRE 432 -32 0 -32 >>WIRE -112 32 -112 -80 >>WIRE 320 64 320 -80 >>WIRE 320 64 304 64 >>WIRE 336 64 320 64 >>WIRE 432 64 432 -32 >>WIRE 432 64 416 64 >>WIRE 464 64 432 64 >>WIRE 464 96 464 64 >>WIRE -112 128 -112 112 >>WIRE -112 128 -208 128 >>WIRE 0 128 0 -32 >>WIRE 80 128 0 128 >>WIRE -112 144 -112 128 >>WIRE -32 192 -48 192 >>WIRE 80 192 48 192 >>WIRE 432 192 432 64 >>WIRE 432 192 304 192 >>WIRE 464 192 464 176 >>WIRE 528 192 464 192 >>WIRE 608 192 592 192 >>WIRE 464 208 464 192 >>WIRE 608 208 608 192 >>WIRE -112 256 -112 240 >>WIRE 80 256 64 256 >>WIRE 400 256 384 256 >>WIRE -208 320 -208 128 >>WIRE 384 320 384 256 >>WIRE 384 320 -208 320 >>WIRE 464 320 464 304 >>WIRE 608 320 608 272 >>FLAG -256 32 0 >>FLAG 80 64 0 >>FLAG 608 320 0 >>FLAG -128 -80 P+ >>FLAG 64 256 P+ >>FLAG 464 320 0 >>FLAG -112 256 0 >>SYMBOL Misc\\NE555 192 160 R0 >>SYMATTR InstName U1 >>SYMBOL voltage -256 -64 R0 >>WINDOW 123 0 0 Left 2 >>WINDOW 39 0 0 Left 2 >>SYMATTR InstName V1 >>SYMATTR Value 10 >>SYMBOL res 432 48 R90 >>WINDOW 0 0 56 VBottom 2 >>WINDOW 3 32 56 VTop 2 >>SYMATTR InstName R1 >>SYMATTR Value 250 >>SYMBOL ind 448 80 R0 >>SYMATTR InstName L1 >>SYMATTR Value 1mh >>SYMATTR SpiceLine Rser=0.1 >>SYMBOL zener 528 208 R270 >>WINDOW 0 32 32 VTop 2 >>WINDOW 3 52 118 VBottom 2 >>SYMATTR InstName D1 >>SYMATTR Value DFLZ33 >>SYMATTR Description Diode >>SYMATTR Type diode >>SYMBOL cap 592 208 R0 >>SYMATTR InstName C1 >>SYMATTR Value 1&#2013266101;f >>SYMBOL npn 400 208 R0 >>SYMATTR InstName Q1 >>SYMATTR Value 2N5550 >>SYMBOL npn -48 144 M0 >>SYMATTR InstName Q2 >>SYMBOL res 64 176 R90 >>WINDOW 0 0 56 VBottom 2 >>WINDOW 3 32 56 VTop 2 >>SYMATTR InstName R3 >>SYMATTR Value 1200 >>SYMBOL res -128 16 R0 >>SYMATTR InstName R4 >>SYMATTR Value 1200 >>TEXT -240 360 Left 0 !.tran 0 0.010 0 0.01 startup >> >>Jamie >> >> >> > > > It's not clear to me what current you need but the voltage does not even > comes close to the 100V you say you want to achieve and that's without load. >
I know, I used a 33V zener that was sitting in LTSPICE.. The point is, with a 100V zener, it will do it just as well as it does at 33v. If I knew more about making models in Spice I would of simply done that how ever, I do more bench testing than I do spice sims. I find that many times live experiments yields different results how ever, I do know this one happens to work on the bench and in spice the same way. Jamie
On 30 Sep., 00:22, Jamie
<jamie_ka1lpa_not_valid_after_ka1l...@charter.net> wrote:
> Jan Panteltje wrote: > > On a sunny day (Wed, 28 Sep 2011 20:55:03 -0400) it happened Jamie > > <jamie_ka1lpa_not_valid_after_ka1l...@charter.net> wrote in > > <t9Pgq.8$Gb...@newsfe08.iad>: > > >>This is my contributions to the already going thread on a 100 volt > >>capable DC-DC buck boost using a 555 and a zener for regulation that > >>uses the minimum parts. I don't even have a timing cap in there. > > >> Set R1 for the Max I you need as the load and the zener will suck > >>up what you don't use to maintain a constant voltage.. Of course this > >>type of boost is only good if your load constraints are not all over th=
e
> >>place. > > >> Replace R1 with a PNP current sink that can be reversed bias with a > >>feed back regulator and you can have a large output unit with low stand > >>by current, instead if using a Zener like I do with low current demands > > >>Version 4 > >>SHEET 1 880 680 > >>WIRE -128 -80 -256 -80 > >>WIRE -112 -80 -128 -80 > >>WIRE 320 -80 -112 -80 > >>WIRE -256 -48 -256 -80 > >>WIRE 432 -32 0 -32 > >>WIRE -112 32 -112 -80 > >>WIRE 320 64 320 -80 > >>WIRE 320 64 304 64 > >>WIRE 336 64 320 64 > >>WIRE 432 64 432 -32 > >>WIRE 432 64 416 64 > >>WIRE 464 64 432 64 > >>WIRE 464 96 464 64 > >>WIRE -112 128 -112 112 > >>WIRE -112 128 -208 128 > >>WIRE 0 128 0 -32 > >>WIRE 80 128 0 128 > >>WIRE -112 144 -112 128 > >>WIRE -32 192 -48 192 > >>WIRE 80 192 48 192 > >>WIRE 432 192 432 64 > >>WIRE 432 192 304 192 > >>WIRE 464 192 464 176 > >>WIRE 528 192 464 192 > >>WIRE 608 192 592 192 > >>WIRE 464 208 464 192 > >>WIRE 608 208 608 192 > >>WIRE -112 256 -112 240 > >>WIRE 80 256 64 256 > >>WIRE 400 256 384 256 > >>WIRE -208 320 -208 128 > >>WIRE 384 320 384 256 > >>WIRE 384 320 -208 320 > >>WIRE 464 320 464 304 > >>WIRE 608 320 608 272 > >>FLAG -256 32 0 > >>FLAG 80 64 0 > >>FLAG 608 320 0 > >>FLAG -128 -80 P+ > >>FLAG 64 256 P+ > >>FLAG 464 320 0 > >>FLAG -112 256 0 > >>SYMBOL Misc\\NE555 192 160 R0 > >>SYMATTR InstName U1 > >>SYMBOL voltage -256 -64 R0 > >>WINDOW 123 0 0 Left 2 > >>WINDOW 39 0 0 Left 2 > >>SYMATTR InstName V1 > >>SYMATTR Value 10 > >>SYMBOL res 432 48 R90 > >>WINDOW 0 0 56 VBottom 2 > >>WINDOW 3 32 56 VTop 2 > >>SYMATTR InstName R1 > >>SYMATTR Value 250 > >>SYMBOL ind 448 80 R0 > >>SYMATTR InstName L1 > >>SYMATTR Value 1mh > >>SYMATTR SpiceLine Rser=3D0.1 > >>SYMBOL zener 528 208 R270 > >>WINDOW 0 32 32 VTop 2 > >>WINDOW 3 52 118 VBottom 2 > >>SYMATTR InstName D1 > >>SYMATTR Value DFLZ33 > >>SYMATTR Description Diode > >>SYMATTR Type diode > >>SYMBOL cap 592 208 R0 > >>SYMATTR InstName C1 > >>SYMATTR Value 1 f > >>SYMBOL npn 400 208 R0 > >>SYMATTR InstName Q1 > >>SYMATTR Value 2N5550 > >>SYMBOL npn -48 144 M0 > >>SYMATTR InstName Q2 > >>SYMBOL res 64 176 R90 > >>WINDOW 0 0 56 VBottom 2 > >>WINDOW 3 32 56 VTop 2 > >>SYMATTR InstName R3 > >>SYMATTR Value 1200 > >>SYMBOL res -128 16 R0 > >>SYMATTR InstName R4 > >>SYMATTR Value 1200 > >>TEXT -240 360 Left 0 !.tran 0 0.010 0 0.01 startup > > >>Jamie > > > It is nice, can it be done without the inverter transistor? > > I did that because it needed to be inverted, as you can see. If you were > looking for a (-) output then the circuit could be altered and yes, only > one transistor is needed, since then, you'd be using a PNP on the top > side and the output of the timer would not need to be inverted. > > =A0 =A0Using a P-channel mosfet as an follower instead sounds attractive =
how
> ever, it'll just drop into linear mode when the output on the source > gets to the point where there isn't enough gate voltage from the timer. > > =A0 =A0I've done this also with a dual comparator (8 pin package) and set=
up
> a window trigger and threshold, like the timer is. With that, you can > simply alter the inputs that are used and you only need one transistor > on the buck switch. > > =A0 =A0It's just with a timer, the parts count is low and it has a hefty > output. :) > > =A0 Something to think about I guess :) > > Jamie > >
I couldn't find the link to the previous thread, but wouldn't a PIC10 or any other small micro be simpler. You get more features, softstart etc If the supply is a problem, the PIC16HV runs at up to 16V (has internal series regulator) Cheers Klaus
Klaus Kragelund <klauskvik@hotmail.com> wrote:

>On 30 Sep., 00:22, Jamie ><jamie_ka1lpa_not_valid_after_ka1l...@charter.net> wrote: >> Jan Panteltje wrote: >> > On a sunny day (Wed, 28 Sep 2011 20:55:03 -0400) it happened Jamie >> > <jamie_ka1lpa_not_valid_after_ka1l...@charter.net> wrote in >> > <t9Pgq.8$Gb...@newsfe08.iad>: >> >> >>This is my contributions to the already going thread on a 100 volt >> >>capable DC-DC buck boost using a 555 and a zener for regulation that >> >>uses the minimum parts. I don't even have a timing cap in there. >> >> >> Set R1 for the Max I you need as the load and the zener will suck >> >>up what you don't use to maintain a constant voltage.. Of course this >> >>type of boost is only good if your load constraints are not all over th= >e >> >>place. >> >> >> Replace R1 with a PNP current sink that can be reversed bias with a >> >>feed back regulator and you can have a large output unit with low stand >> >>by current, instead if using a Zener like I do with low current demands >> >> >>Jamie >> >> > It is nice, can it be done without the inverter transistor? >> >> I did that because it needed to be inverted, as you can see. If you were >> looking for a (-) output then the circuit could be altered and yes, only >> one transistor is needed, since then, you'd be using a PNP on the top >> side and the output of the timer would not need to be inverted. >> >> =A0 =A0Using a P-channel mosfet as an follower instead sounds attractive = >how >> ever, it'll just drop into linear mode when the output on the source >> gets to the point where there isn't enough gate voltage from the timer. >> >> =A0 =A0I've done this also with a dual comparator (8 pin package) and set= > up >> a window trigger and threshold, like the timer is. With that, you can >> simply alter the inputs that are used and you only need one transistor >> on the buck switch. >> >> =A0 =A0It's just with a timer, the parts count is low and it has a hefty >> output. :) >> >> =A0 Something to think about I guess :) >> >> Jamie >> >> > >I couldn't find the link to the previous thread, but wouldn't a PIC10 >or any other small micro be simpler. You get more features, softstart >etc
Cycle-by-cycle current limiting is a piece of cake with an NE555. This is one of my designs to create 55V for a few hundred uA (post regulators not shown): http://img840.imageshack.us/img840/3929/ne555stepup.jpg -- Failure does not prove something is impossible, failure simply indicates you are not using the right tools... nico@nctdevpuntnl (punt=.) --------------------------------------------------------------