On Sat, 1 Jun 2013 18:40:15 -0500, "Tim Williams" <tmoranwms@charter.net> wrote:>Quaint. I've been doing that for many years, and of course the circuit >dates back to any tube supply in existence.Never hurts to remember the old stuff. 6080s and VR tubes and like that. Two transistors give rather>poor performance (not much better than the tube circuit). A diff hardly >costs any board area. >http://webpages.charter.net/dawill/tmoranwms/Elec_Pulse1.gif18 parts vs 5! What is the 100 uH inductor for?> >Of course, these days I'd just make the switcher right to begin with. I >have a few jellybean circuits I play with, which only require a few more >transistors than this. Or, God forbid, an IC.The only candidate I found was the LM317HV, which is a big TO-220. -- John Larkin Highland Technology Inc www.highlandtechnology.com jlarkin at highlandtechnology dot com Precision electronic instrumentation Picosecond-resolution Digital Delay and Pulse generators Custom timing and laser controllers Photonics and fiberoptic TTL data links VME analog, thermocouple, LVDT, synchro, tachometer Multichannel arbitrary waveform generators
low power, HV-in regulator with depletion mosfet
Started by ●June 1, 2013
Reply by ●June 1, 20132013-06-01
Reply by ●June 1, 20132013-06-01
John Larkin wrote:> On Sat, 1 Jun 2013 18:40:15 -0500, "Tim Williams" <tmoranwms@charter.net> wrote: > > >>Quaint. I've been doing that for many years, and of course the circuit >>dates back to any tube supply in existence. > > > Never hurts to remember the old stuff. 6080s and VR tubes and like that. > > > Two transistors give rather > >>poor performance (not much better than the tube circuit). A diff hardly >>costs any board area. >>http://webpages.charter.net/dawill/tmoranwms/Elec_Pulse1.gif > > > 18 parts vs 5! What is the 100 uH inductor for? > > >>Of course, these days I'd just make the switcher right to begin with. I >>have a few jellybean circuits I play with, which only require a few more >>transistors than this. Or, God forbid, an IC. > > > The only candidate I found was the LM317HV, which is a big TO-220. > >Looking at that Elec_Pulse1.gif, I wasn't aware that a 2N3904 could hold back 120Volts on the collector? Last I checked, I think the V(brk)CEO was around 40. Vcbo a little higher.. Oh well. Jamie
Reply by ●June 1, 20132013-06-01
On Sat, 01 Jun 2013 21:12:43 -0400, Jamie <jamie_ka1lpa_not_valid_after_ka1lpa_@charter.net> wrote:>John Larkin wrote: > >> On Sat, 1 Jun 2013 18:40:15 -0500, "Tim Williams" <tmoranwms@charter.net> wrote: >> >> >>>Quaint. I've been doing that for many years, and of course the circuit >>>dates back to any tube supply in existence. >> >> >> Never hurts to remember the old stuff. 6080s and VR tubes and like that. >> >> >> Two transistors give rather >> >>>poor performance (not much better than the tube circuit). A diff hardly >>>costs any board area. >>>http://webpages.charter.net/dawill/tmoranwms/Elec_Pulse1.gif >> >> >> 18 parts vs 5! What is the 100 uH inductor for? >> >> >>>Of course, these days I'd just make the switcher right to begin with. I >>>have a few jellybean circuits I play with, which only require a few more >>>transistors than this. Or, God forbid, an IC. >> >> >> The only candidate I found was the LM317HV, which is a big TO-220. >> >> >Looking at that Elec_Pulse1.gif, I wasn't aware that a 2N3904 could hold >back 120Volts on the collector? > > Last I checked, I think the V(brk)CEO was around 40. Vcbo a little >higher.. > > Oh well. > >JamieIt's probably one of those hand-selected avalanche situations. The HV is tuned with the pot, too. This circuit *wants* the 3904 to break down. The Zetex avalanche transistors are much more predictable, but expensive and relatively slow. -- John Larkin Highland Technology Inc www.highlandtechnology.com jlarkin at highlandtechnology dot com Precision electronic instrumentation Picosecond-resolution Digital Delay and Pulse generators Custom timing and laser controllers Photonics and fiberoptic TTL data links VME analog, thermocouple, LVDT, synchro, tachometer Multichannel arbitrary waveform generators
Reply by ●June 1, 20132013-06-01
"John Larkin" <jjlarkin@highNOTlandTHIStechnologyPART.com> wrote in message news:of2lq891statcd5n5tdbp63k1qujs87ncb@4ax.com...>>http://webpages.charter.net/dawill/tmoranwms/Elec_Pulse1.gif > > 18 parts vs 5! What is the 100 uH inductor for?Keeping the risetime out of the regulator. Seems like the cap is on the wrong side, which may be the case. Superfluous I'm sure. You recognize the last section, of course. Tim -- Deep Friar: a very philosophical monk. Website: http://seventransistorlabs.com
Reply by ●June 2, 20132013-06-02
"John Larkin" <jjlarkin@highNOTlandTHIStechnologyPART.com> wrote in message news:vsalq8tbaevp7doi6el1uulvh2a0d7iq9n@4ax.com...>>Looking at that Elec_Pulse1.gif, I wasn't aware that a 2N3904 could hold >>back 120Volts on the collector? >> >> Last I checked, I think the V(brk)CEO was around 40. Vcbo a little >>higher.. >> >> Oh well.I find they regularly handle 80-100. 2N4401s also, but they don't do the avalanche pulse thing (at least as easily). Not that I would operate them under such conditions, for, say, linear amplification (for which you might achieve negative hFE, like the germanium of old!), or switching (where the storage and 2nd breakdown will toast it anyway). The PNP CCS in that Cdss test rig I posted about last week, it's only rated for 160V or so, but tonight I've just taken it up to 220 without a problem. Measuring the test rig, with a very low capacitance device (a BFQ225, only rated for 100V, but it breaks down around 150), it seems to have a constant 60pF capacitance, independent of voltage (at least, down to -65Vce, apparently). One thing that surprises me about BJTs versus MOSFETs: the capacitance is small and relatively constant. Ancient DMOS have relatively constant capacitance, but they're also an order of magnitude worse in performance than modern devices.> It's probably one of those hand-selected avalanche situations. The HV is > tuned > with the pot, too. This circuit *wants* the 3904 to break down. > > The Zetex avalanche transistors are much more predictable, but expensive > and > relatively slow.Hand-made test equipment is hardly production material, but of all the transistors I've tested (2N3904s, 2N2369s, and a few RF types), if a single unit will achieve pulse breakdown, it's characteristic of the type, not just that particular unit. I've used TO-92s from various manufacturers, and SOT-23s from several (i.e., MMBT), with the same results. RF types may be useful at lower voltages. I found a 2SA1206 or something (I'm sure that's the wrong number), 30V 50mA 2GHz PNP sort of thing, which made nice pulses at 60V. Beats me if higher voltage types can be convinced of doing the same. Avalanche pulsing even works on a solderless breadboard, where the absolute worst risetime I was able to create was 4ns, half of which was the scope anyway. '3904s are slower than '2369s, but not by much, and still faster than the Zetex ones. Tim -- Deep Friar: a very philosophical monk. Website: http://seventransistorlabs.com
Reply by ●June 2, 20132013-06-02
John Larkin wrote:> On Sat, 01 Jun 2013 21:12:43 -0400, Jamie > <jamie_ka1lpa_not_valid_after_ka1lpa_@charter.net> wrote: > > >>John Larkin wrote: >> >> >>>On Sat, 1 Jun 2013 18:40:15 -0500, "Tim Williams" <tmoranwms@charter.net> wrote: >>> >>> >>> >>>>Quaint. I've been doing that for many years, and of course the circuit >>>>dates back to any tube supply in existence. >>> >>> >>>Never hurts to remember the old stuff. 6080s and VR tubes and like that. >>> >>> >>> Two transistors give rather >>> >>> >>>>poor performance (not much better than the tube circuit). A diff hardly >>>>costs any board area. >>>>http://webpages.charter.net/dawill/tmoranwms/Elec_Pulse1.gif >>> >>> >>>18 parts vs 5! What is the 100 uH inductor for? >>> >>> >>> >>>>Of course, these days I'd just make the switcher right to begin with. I >>>>have a few jellybean circuits I play with, which only require a few more >>>>transistors than this. Or, God forbid, an IC. >>> >>> >>>The only candidate I found was the LM317HV, which is a big TO-220. >>> >>> >> >>Looking at that Elec_Pulse1.gif, I wasn't aware that a 2N3904 could hold >>back 120Volts on the collector? >> >> Last I checked, I think the V(brk)CEO was around 40. Vcbo a little >>higher.. >> >> Oh well. >> >>Jamie > > > It's probably one of those hand-selected avalanche situations. The HV is tuned > with the pot, too. This circuit *wants* the 3904 to break down. > > The Zetex avalanche transistors are much more predictable, but expensive and > relatively slow. > >Explaining it away as an intentional design decision shows a cover up. Well seasoned engineers can and do make mistakes, too. Jamie
Reply by ●June 2, 20132013-06-02
Jamie <jamie_ka1lpa_not_valid_after_ka1lpa_@charter.net> writes:> John Larkin wrote: > >> On Sat, 01 Jun 2013 21:12:43 -0400, Jamie >> <jamie_ka1lpa_not_valid_after_ka1lpa_@charter.net> wrote: >> >> >>>John Larkin wrote: >>> >>> >>>>On Sat, 1 Jun 2013 18:40:15 -0500, "Tim Williams" <tmoranwms@charter.net> wrote: >>>> >>>> >>>> >>>>> Quaint. I've been doing that for many years, and of course the >>>>> circuit dates back to any tube supply in existence. >>>> >>>> >>>>Never hurts to remember the old stuff. 6080s and VR tubes and like that. >>>> >>>> >>>> Two transistors give rather >>>> >>>> >>>>> poor performance (not much better than the tube circuit). A diff >>>>> hardly costs any board area. >>>>>http://webpages.charter.net/dawill/tmoranwms/Elec_Pulse1.gif >>>> >>>> >>>>18 parts vs 5! What is the 100 uH inductor for? >>>> >>>> >>>> >>>>> Of course, these days I'd just make the switcher right to begin >>>>> with. I have a few jellybean circuits I play with, which only >>>>> require a few more transistors than this. Or, God forbid, an IC. >>>> >>>> >>>>The only candidate I found was the LM317HV, which is a big TO-220. >>>> >>>> >>> >>>Looking at that Elec_Pulse1.gif, I wasn't aware that a 2N3904 could hold >>>back 120Volts on the collector? >>> >>> Last I checked, I think the V(brk)CEO was around 40. Vcbo a little >>> higher.. >>> >>> Oh well. >>> >>>Jamie >> >> >> It's probably one of those hand-selected avalanche situations. The HV is tuned >> with the pot, too. This circuit *wants* the 3904 to break down. >> >> The Zetex avalanche transistors are much more predictable, but expensive and >> relatively slow. >> >> > > Explaining it away as an intentional design decision shows a cover > up. Well seasoned engineers can and do make mistakes, too.It's not "explaining it away", it is the entire point of the circuit, which you missed. -- John Devereux
Reply by ●June 2, 20132013-06-02
On Sun, 02 Jun 2013 14:36:54 +0100, John Devereux <john@devereux.me.uk> wrote:>Jamie <jamie_ka1lpa_not_valid_after_ka1lpa_@charter.net> writes: > >> John Larkin wrote: >> >>> >>> It's probably one of those hand-selected avalanche situations. The HV is tuned >>> with the pot, too. This circuit *wants* the 3904 to break down. >>> >>> The Zetex avalanche transistors are much more predictable, but expensive and >>> relatively slow. >>> >>> >> >> Explaining it away as an intentional design decision shows a cover >> up. Well seasoned engineers can and do make mistakes, too. > >It's not "explaining it away", it is the entire point of the circuit, >which you missed.Zetex makes some really good components.
Reply by ●June 2, 20132013-06-02
On Sat, 01 Jun 2013 10:52:53 -0700, John Larkin <jjlarkin@highNOTlandTHIStechnologyPART.com> wrote: Looks remarkably like... www.analog-innovations.com/SED/SingleLoopController_00056_MOD3.pdf dating back to October, 2012, which Larkin roundly criticized. Don't the same criticisms apply now ?>:-}>Version 4 >SHEET 1 1888 724 >WIRE 768 -64 688 -64 >WIRE 816 -64 768 -64[snip] Trimmed for brevity, find full asc listing at... From: John Larkin <jjlarkin@highNOTlandTHIStechnologyPART.com> Newsgroups: sci.electronics.design Subject: low power, HV-in regulator with depletion mosfet Date: Sat, 01 Jun 2013 10:52:53 -0700 Message-ID: <r3dkq8hseog2jes1r762hlq2k8418mdfqf@4ax.com>>TEXT 920 488 Left 2 ;JL June 1 2013 >TEXT -376 624 Left 2 !.model DZ5.6 D(Vfwd=0.6 Ron=1 Roff=1G Vrev=5.6) >TEXT -200 464 Left 2 !.include Supertex.lib >TEXT 1424 72 Left 2 ;Ilim test >TEXT 424 344 Left 2 ;Quad R-pack...Jim Thompson -- | James E.Thompson | mens | | Analog Innovations | et | | Analog/Mixed-Signal ASIC's and Discrete Systems | manus | | San Tan Valley, AZ 85140 Skype: Contacts Only | | | 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.
Reply by ●June 2, 20132013-06-02
On Sat, 01 Jun 2013 16:53:30 -0700, John Larkin wrote:> My regulation requirement isn't tight... I'm just powering opamps. If the > voltage comes out too low, I can always go to a higher zener voltage; it's not a > potential disaster. > > Here's data on a 6.2 volt part: > > https://dl.dropboxusercontent.com/u/53724080/Parts/Diodes/MMBZ5234BL.pdfI spun it again, with a MMBZ5232BT (5.6V). My version, with more zener current, drops v(out) by 3uV at 5mA draw. Without the extra resistor, yours drops by 47mV.> If we wanted more current, it would be better > to change R2, since the voltage there is more constant.Lowering R2 instead increases zener current, but degrades regulation. .SUBCKT DI_MMBZ5232BT 1 2 * Terminals A K D1 1 2 DF DZ 3 1 DR VZ 2 3 3.14 .MODEL DF D ( IS=11.0p RS=31.2 N=1.10 + CJO=57.6p VJ=0.750 M=0.330 TT=50.1n ) .MODEL DR D ( IS=2.21f RS=7.11 N=3.00 ) .ENDS -- "For a successful technology, reality must take precedence over public relations, for nature cannot be fooled." (Richard Feynman)
