On Sun, 19 Jul 2015 14:59:32 -0700 (PDT), edward.ming.lee@gmail.com wrote:>On Sunday, July 19, 2015 at 2:44:24 PM UTC-7, bitrex wrote: >> On 7/19/2015 5:39 PM, edward.ming.lee@gmail.com wrote: >> > On Sunday, July 19, 2015 at 2:26:18 PM UTC-7, bitrex wrote: >> >> On 7/19/2015 2:04 PM, Phil Hobbs wrote: >> >>> A $1.50 boost and a $1.50 buck connected as an inverter gives the effect of stacking two of the fancier ones, using the isolation of the USB brick. Of course it may not work if the OP needs to use the 5V in the same circuit. >> >>> >> >>> Cheers >> >>> >> >>> Phil Hobbs >> >>> >> >> >> >> I am going to need +5/-5 and +48 unfortunately... >> > >> > Perhaps one cheap non-isolated and one expensive stack-up isolated. A bit expensive, but still much cheaper than what you can build with discretes. >> > >> >> If I turn this hobby product into an actual product, space is also at a >> premium. The current requirements of the -5 volt rail are modest - a >> while back someone pointed out a circuit that used a MAX232 to generate >> a negative rail for an entire board. How would the "stack-up isolated" >> work? > >Yes, have John ('s suggestion) sitting on top of Phip ('s suggestion). John would be totally isolated from the rest (Sorry, John, it's just a joke).Snarl. Snap.>A Max232 can also generate the negative rail (probably -7 to -10) then regulate it to -5V.The same series of CUI bricks has a 5 to +-5 version. Or use an LM2662. -- John Larkin Highland Technology, Inc picosecond timing laser drivers and controllers jlarkin att highlandtechnology dott com http://www.highlandtechnology.com
charge pump/boost converter
Started by ●July 18, 2015
Reply by ●July 19, 20152015-07-19
Reply by ●July 20, 20152015-07-20
On Sunday, July 19, 2015 at 1:29:37 PM UTC+2, Chris Jones wrote:> On 19/07/2015 18:26, Bill Sloman wrote: > > On Sunday, July 19, 2015 at 1:49:42 AM UTC+2, M Philbrook wrote: > >> In article <c228b7df-ec64-469a-ae5f-f4ae29cfe028@googlegroups.com>, > >> bill.sloman@gmail.com says... > >>> > >>> On Saturday, July 18, 2015 at 5:50:11 PM UTC+2, John Larkin wrote: > >>>> On Sat, 18 Jul 2015 09:39:34 -0400, bitrex > >>>> <bitrex@de.lete.earthlink.net> wrote: > >>>> > >>>>> > >>>>> For a hobby project, I'd like to be able to generate +48 volts or so > >>>> >from +5 volt USB. Current requirements are small, maybe 15 mA or so? > >>>>> I'd like uh, low noise (I don't have an exact spec so this is just kind > >>>>> of existential at this point), so maybe a charge pump would be in order > >>>>> rather than a boost switcher? > >>>>> > >>>>> Does anyone make a charge pump IC that I could feed an external clock > >>>>> to, with outputs suitable for running something like a Dickson pump? > >>>>> Maybe that would be too many stages to go from +5 to +48... > >>>> > >>>> Two of these > >>>> > >>>> http://www.digikey.com/product-detail/en/PDS1-S5-S24-M-TR/102-2973-2-ND/4006941 > >>>> > >>>> with the outputs in series would work. They are fairly quiet, and you > >>>> could add a little filtering to help. At light loads, their output > >>>> tends to be a few per cent high. But then, 5 volts from USB may not > >>>> really be 5 volts. > >>>> > >>>> For really quiet, consider some sort of sinewave drive step-up > >>>> transformer. > >>> > >>> A Baxandall Class-D oscillator - one step-up transformer and one inductor - would work well. MOS-FET transistors do a bit better than bipolar transistors, but Baxandall's paper rather pre-dates them. > >>> > >>> http://sophia-elektronica.com/0344_001_Baxandal.pdf > >>> > >>> http://sophia-elektronica.com/Baxandall_parallel-resonant_Class-D_oscillator1.htm > >> > >> Oh God, You just couldn't keep that failed OSC out of the subject! > > > > The 1959 Baxandall class_D oscillator isn't "failed". To quote from my web-site "The circuit is probably best known from Jim Williams' series of application notes for Linear Technology, on high frequency inverters for driving cold cathode back-lights used in laptop computers (application notes AN45, AN49, AN51, AN55, AN61, AN65)." These apparently were Linear Technology's most popular application notes for quite a while. > > > > It has been claimed that Jim Williams got the circuit from England, without the Baxandall label. > > > > I do have a low distortion variant of the class-D oscillator, with a current mirror rather than the feed inductor, but that's not the low distortion oscillator I'm working on at the moment. > > > > You are distinctly public-spirited in regularly reminding us that you are an idiot, but you really don't have to do it quite as often as you do. > > > > The circuit on your website bears a lot of resemblance to the one in > Figure 2 of G3VA's Technical Topics column in Radio Communications > magazine from May 2002. He refers to it as the "Mesny VHF power > oscillator of the 1920s" though of course then it used triodes not > MOSFETs, and needed a separate winding for the gates to get the DC bias > right. There is a picture of it under the name Mesny here: > http://www.r-type.org/articles/art-106.htm > > I think some people call them Kalitrons too: > http://www.vk6fh.com/vk6fh/kalitron.htm > > It is one of the most popular topologies for on-chip LC oscillators in > the synthesisers of cellphone radios - though usually with fancy > amplitude control etc. and sometimes without the inductor in the supply, > or with the supply inductor moved to the tail of the diff pair. Whatever > it is called, it was a very old topology in 1959 and yet billions of > them have been made in recent years.Jim William's version has the inductor in the tail of the differential pair. No inductor gives you a rather different beast, though I've used a current mirror to do much the same job to get a rather less distorted sine wave. "The circuit is probably best known from Jim Williams' series of application notes for Linear Technology, on high frequency inverters for driving cold cathode back-lights used in laptop computers (application notes AN45, AN49, AN51, AN55, AN61, AN65)." These apparently were Linear Technology's most popular application notes for quite a while, so it's not surprising that the circuit is now well-known. Nobody has ever called it a Mesny power oscillator before anywhere I've looked. Peter Baxandall seems to have invented the circuit to drive high-turns ration transformers to step up +12V supplies to a kilovolt or so to drive photomulitpliers. That's not remotely a VHF circuit, though VHF circuits are presumably rather more sensitive to the rather lower inter-winding capacitances seen in more conventional transformers. The Proceedings of the British Institute of Electrical Engineers is a peer-reviewed journal so presumably the reviewers didn't see the similarity to the Mesny power amplifier either. -- Bill Sloman, Sydney
Reply by ●July 20, 20152015-07-20
On Sunday, July 19, 2015 at 6:03:34 PM UTC+2, M Philbrook wrote:> In article <8ea10652-9957-4b3f-8076-c96625387925@googlegroups.com>, > bill.sloman@gmail.com says... > > > Oh God, You just couldn't keep that failed OSC out of the subject! > > > > The 1959 Baxandall class_D oscillator isn't "failed". To quote from my web-site "The circuit is probably best known from Jim Williams' series of application notes for Linear Technology, on high frequency inverters for driving cold cathode back-lights used in laptop computers (application notes AN45, AN49, AN51, AN55, AN61, AN65)." These apparently were Linear Technology's most popular application notes for quite a while. > > > > It has been claimed that Jim Williams got the circuit from England, without the Baxandall label. > > > > I do have a low distortion variant of the class-D oscillator, with a current mirror rather than the feed inductor, but that's not the low distortion oscillator I'm working on at the moment. > > > > You are distinctly public-spirited in regularly reminding us that you are an idiot, but you really don't have to do it quite as often as you do. > > You know as well I do what was meant by that > comment..Sure - you don't like being shown up as an idiot. Sadly, the response identified you as an idiot just as clearly as all the other rubbish you post. -- Bill Sloman, Sydney
Reply by ●July 20, 20152015-07-20
On Sunday, July 19, 2015 at 7:40:19 PM UTC+2, John Larkin wrote:> On Sat, 18 Jul 2015 19:53:31 -0400, M Philbrook > <jamie_ka1lpa@charter.net> wrote: > > >In article <c228b7df-ec64-469a-ae5f-f4ae29cfe028@googlegroups.com>, > >bill.sloman@gmail.com says... > >> > >> On Saturday, July 18, 2015 at 5:50:11 PM UTC+2, John Larkin wrote: > >> > On Sat, 18 Jul 2015 09:39:34 -0400, bitrex > >> > <bitrex@de.lete.earthlink.net> wrote: > >> > > >> > > > >> > >For a hobby project, I'd like to be able to generate +48 volts or so > >> > >from +5 volt USB. Current requirements are small, maybe 15 mA or so? > >> > >I'd like uh, low noise (I don't have an exact spec so this is just kind > >> > >of existential at this point), so maybe a charge pump would be in order > >> > >rather than a boost switcher? > >> > > > >> > >Does anyone make a charge pump IC that I could feed an external clock > >> > >to, with outputs suitable for running something like a Dickson pump? > >> > >Maybe that would be too many stages to go from +5 to +48... > >> > > >> > Two of these > >> > > >> > http://www.digikey.com/product-detail/en/PDS1-S5-S24-M-TR/102-2973-2-ND/4006941 > >> > > >> > with the outputs in series would work. They are fairly quiet, and you > >> > could add a little filtering to help. At light loads, their output > >> > tends to be a few per cent high. But then, 5 volts from USB may not > >> > really be 5 volts. > >> > > >> > For really quiet, consider some sort of sinewave drive step-up > >> > transformer. > >> > >> A Baxandall Class-D oscillator - one step-up transformer and one inductor - would work well. MOS-FET transistors do a bit better than bipolar transistors, but Baxandall's paper rather pre-dates them. > >> > >> http://sophia-elektronica.com/0344_001_Baxandal.pdf > >> > >> http://sophia-elektronica.com/Baxandall_parallel-resonant_Class-D_oscillator1.htm > > > >Oh God, You just couldn't keep that failed OSC out of th subject! > > It's an interesting circuit from a time scaling standpoint. It will > oscillate at tens of KHz, but it takes decades to build.John Larkin is too dim to notice the difference between a low distortion oscillator and the Baxandall/Jim Williams oscillator. "The circuit is probably best known from Jim Williams' series of application notes for Linear Technology, on high frequency inverters for driving cold cathode back-lights used in laptop computers (application notes AN45, AN49, AN51, AN55, AN61, AN65)." These apparently were Linear Technology's most popular application notes for quite a while. Nobody has had any trouble building them in jig time. Except perhaps John Larkin, who can't cope with transformers that he can't buy off the shelf. -- Bill Sloman, Sydney
Reply by ●July 20, 20152015-07-20
Den mandag den 20. juli 2015 kl. 17.24.11 UTC+2 skrev Bill Sloman:> On Sunday, July 19, 2015 at 7:40:19 PM UTC+2, John Larkin wrote: > > On Sat, 18 Jul 2015 19:53:31 -0400, M Philbrook > > <jamie_ka1lpa@charter.net> wrote: > > > > >In article <c228b7df-ec64-469a-ae5f-f4ae29cfe028@googlegroups.com>, > > >bill.sloman@gmail.com says... > > >> > > >> On Saturday, July 18, 2015 at 5:50:11 PM UTC+2, John Larkin wrote: > > >> > On Sat, 18 Jul 2015 09:39:34 -0400, bitrex > > >> > <bitrex@de.lete.earthlink.net> wrote: > > >> > > > >> > > > > >> > >For a hobby project, I'd like to be able to generate +48 volts or so > > >> > >from +5 volt USB. Current requirements are small, maybe 15 mA or so? > > >> > >I'd like uh, low noise (I don't have an exact spec so this is just kind > > >> > >of existential at this point), so maybe a charge pump would be in order > > >> > >rather than a boost switcher? > > >> > > > > >> > >Does anyone make a charge pump IC that I could feed an external clock > > >> > >to, with outputs suitable for running something like a Dickson pump? > > >> > >Maybe that would be too many stages to go from +5 to +48... > > >> > > > >> > Two of these > > >> > > > >> > http://www.digikey.com/product-detail/en/PDS1-S5-S24-M-TR/102-2973-2-ND/4006941 > > >> > > > >> > with the outputs in series would work. They are fairly quiet, and you > > >> > could add a little filtering to help. At light loads, their output > > >> > tends to be a few per cent high. But then, 5 volts from USB may not > > >> > really be 5 volts. > > >> > > > >> > For really quiet, consider some sort of sinewave drive step-up > > >> > transformer. > > >> > > >> A Baxandall Class-D oscillator - one step-up transformer and one inductor - would work well. MOS-FET transistors do a bit better than bipolar transistors, but Baxandall's paper rather pre-dates them. > > >> > > >> http://sophia-elektronica.com/0344_001_Baxandal.pdf > > >> > > >> http://sophia-elektronica.com/Baxandall_parallel-resonant_Class-D_oscillator1.htm > > > > > >Oh God, You just couldn't keep that failed OSC out of th subject! > > > > It's an interesting circuit from a time scaling standpoint. It will > > oscillate at tens of KHz, but it takes decades to build. > > John Larkin is too dim to notice the difference between a low distortion oscillator and the Baxandall/Jim Williams oscillator. >Though it can hardly come as a surprise that you get teased about it since you have been talking about for years and still haven't gotten around to building it, as if a bit of table space for a soldering iron and time, for someone who doesn't have to go to work everyday, is impossible to find> "The circuit is probably best known from Jim Williams' series of application notes for Linear Technology, on high frequency inverters for driving cold cathode back-lights used in laptop computers (application notes AN45, AN49, AN51, AN55, AN61, AN65)." These apparently were Linear Technology's most popular application notes for quite a while. > > Nobody has had any trouble building them in jig time. Except perhaps John Larkin, who can't cope with transformers that he can't buy off the shelf. >Aiming to build stuff from things you can get cheap and fast off the shelf is just common sense -Lasse
Reply by ●July 21, 20152015-07-21
On Tuesday, July 21, 2015 at 12:38:07 AM UTC+2, Lasse Langwadt Christensen wrote:> Den mandag den 20. juli 2015 kl. 17.24.11 UTC+2 skrev Bill Sloman: > > On Sunday, July 19, 2015 at 7:40:19 PM UTC+2, John Larkin wrote: > > > On Sat, 18 Jul 2015 19:53:31 -0400, M Philbrook > > > <jamie_ka1lpa@charter.net> wrote: > > > > > > >In article <c228b7df-ec64-469a-ae5f-f4ae29cfe028@googlegroups.com>, > > > >bill.sloman@gmail.com says... > > > >> > > > >> On Saturday, July 18, 2015 at 5:50:11 PM UTC+2, John Larkin wrote: > > > >> > On Sat, 18 Jul 2015 09:39:34 -0400, bitrex > > > >> > <bitrex@de.lete.earthlink.net> wrote: > > > >> > > > > >> > > > > > >> > >For a hobby project, I'd like to be able to generate +48 volts or so > > > >> > >from +5 volt USB. Current requirements are small, maybe 15 mA or so? > > > >> > >I'd like uh, low noise (I don't have an exact spec so this is just kind > > > >> > >of existential at this point), so maybe a charge pump would be in order > > > >> > >rather than a boost switcher? > > > >> > > > > > >> > >Does anyone make a charge pump IC that I could feed an external clock > > > >> > >to, with outputs suitable for running something like a Dickson pump? > > > >> > >Maybe that would be too many stages to go from +5 to +48... > > > >> > > > > >> > Two of these > > > >> > > > > >> > http://www.digikey.com/product-detail/en/PDS1-S5-S24-M-TR/102-2973-2-ND/4006941 > > > >> > > > > >> > with the outputs in series would work. They are fairly quiet, and you > > > >> > could add a little filtering to help. At light loads, their output > > > >> > tends to be a few per cent high. But then, 5 volts from USB may not > > > >> > really be 5 volts. > > > >> > > > > >> > For really quiet, consider some sort of sinewave drive step-up > > > >> > transformer. > > > >> > > > >> A Baxandall Class-D oscillator - one step-up transformer and one inductor - would work well. MOS-FET transistors do a bit better than bipolar transistors, but Baxandall's paper rather pre-dates them. > > > >> > > > >> http://sophia-elektronica.com/0344_001_Baxandal.pdf > > > >> > > > >> http://sophia-elektronica.com/Baxandall_parallel-resonant_Class-D_oscillator1.htm > > > > > > > >Oh God, You just couldn't keep that failed OSC out of th subject! > > > > > > It's an interesting circuit from a time scaling standpoint. It will > > > oscillate at tens of KHz, but it takes decades to build. > > > > John Larkin is too dim to notice the difference between a low distortion oscillator and the Baxandall/Jim Williams oscillator. > > Though it can hardly come as a surprise that you get teased about it since > you have been talking about for years and still haven't gotten around to > building it, as if a bit of table space for a soldering iron and time, for > someone who doesn't have to go to work everyday, is impossible to find.I'd gotten most of the way to building an example - bought all the parts, including getting the specially wound transformers - a few years ago, just before I moved back to Australia, which gave me enough time to think up a better variation, which I may get built real soon now, if I'm lucky. It's not got much to do with Baxandall's class-D oscillator (though my variant of that is what got me started) but Jamie and John are too dim to make that kind of fine distinction.> > "The circuit is probably best known from Jim Williams' series of application notes for Linear Technology, on high frequency inverters for driving cold cathode back-lights used in laptop computers (application notes AN45, AN49, AN51, AN55, AN61, AN65)." These apparently were Linear Technology's most popular application notes for quite a while. > > > > Nobody has had any trouble building them in jig time. Except perhaps John Larkin, who can't cope with transformers that he can't buy off the shelf. > > > > Aiming to build stuff from things you can get cheap and fast off the shelf is just common senseRestricting yourself to components which you can buy cheaply off the shelf rather narrows your range, particularly when it comes to transformers. -- Bill Sloman, Sydney
Reply by ●July 21, 20152015-07-21
On 07/21/2015 11:46 AM, Bill Sloman wrote:> On Tuesday, July 21, 2015 at 12:38:07 AM UTC+2, Lasse Langwadt > Christensen wrote: >> Den mandag den 20. juli 2015 kl. 17.24.11 UTC+2 skrev Bill Sloman: >>> On Sunday, July 19, 2015 at 7:40:19 PM UTC+2, John Larkin wrote: >>>> On Sat, 18 Jul 2015 19:53:31 -0400, M Philbrook >>>> <jamie_ka1lpa@charter.net> wrote: >>>> >>>>> In article >>>>> <c228b7df-ec64-469a-ae5f-f4ae29cfe028@googlegroups.com>, >>>>> bill.sloman@gmail.com says... >>>>>> >>>>>> On Saturday, July 18, 2015 at 5:50:11 PM UTC+2, John Larkin >>>>>> wrote: >>>>>>> On Sat, 18 Jul 2015 09:39:34 -0400, bitrex >>>>>>> <bitrex@de.lete.earthlink.net> wrote: >>>>>>> >>>>>>>> >>>>>>>> For a hobby project, I'd like to be able to generate >>>>>>>> +48 volts or so from +5 volt USB. Current requirements >>>>>>>> are small, maybe 15 mA or so? I'd like uh, low noise (I >>>>>>>> don't have an exact spec so this is just kind of >>>>>>>> existential at this point), so maybe a charge pump >>>>>>>> would be in order rather than a boost switcher? >>>>>>>> >>>>>>>> Does anyone make a charge pump IC that I could feed an >>>>>>>> external clock to, with outputs suitable for running >>>>>>>> something like a Dickson pump? Maybe that would be too >>>>>>>> many stages to go from +5 to +48... >>>>>>> >>>>>>> Two of these >>>>>>> >>>>>>> http://www.digikey.com/product-detail/en/PDS1-S5-S24-M-TR/102-2973-2-ND/4006941 >>>>>>> >>>>>>> >>>>>>>with the outputs in series would work. They are fairly quiet, and you>>>>>>> could add a little filtering to help. At light loads, >>>>>>> their output tends to be a few per cent high. But then, 5 >>>>>>> volts from USB may not really be 5 volts. >>>>>>> >>>>>>> For really quiet, consider some sort of sinewave drive >>>>>>> step-up transformer. >>>>>> >>>>>> A Baxandall Class-D oscillator - one step-up transformer >>>>>> and one inductor - would work well. MOS-FET transistors do >>>>>> a bit better than bipolar transistors, but Baxandall's >>>>>> paper rather pre-dates them. >>>>>> >>>>>> http://sophia-elektronica.com/0344_001_Baxandal.pdf >>>>>> >>>>>> http://sophia-elektronica.com/Baxandall_parallel-resonant_Class-D_oscillator1.htm >>>>> >>>>> >>>>>>Oh God, You just couldn't keep that failed OSC out of th subject!>>>> >>>> It's an interesting circuit from a time scaling standpoint. It >>>> will oscillate at tens of KHz, but it takes decades to build. >>> >>> John Larkin is too dim to notice the difference between a low >>> distortion oscillator and the Baxandall/Jim Williams oscillator. >> >> Though it can hardly come as a surprise that you get teased about >> it since you have been talking about for years and still haven't >> gotten around to building it, as if a bit of table space for a >> soldering iron and time, for someone who doesn't have to go to work >> everyday, is impossible to find. > > I'd gotten most of the way to building an example - bought all the > parts, including getting the specially wound transformers - a few > years ago, just before I moved back to Australia, which gave me > enough time to think up a better variation, which I may get built > real soon now, if I'm lucky. > > It's not got much to do with Baxandall's class-D oscillator (though > my variant of that is what got me started) but Jamie and John are too > dim to make that kind of fine distinction. > >>> "The circuit is probably best known from Jim Williams' series of >>> application notes for Linear Technology, on high frequency >>> inverters for driving cold cathode back-lights used in laptop >>> computers (application notes AN45, AN49, AN51, AN55, AN61, >>> AN65)." These apparently were Linear Technology's most popular >>> application notes for quite a while. >>> >>> Nobody has had any trouble building them in jig time. Except >>> perhaps John Larkin, who can't cope with transformers that he >>> can't buy off the shelf.. >>> >> >> Aiming to build stuff from things you can get cheap and fast off >> the shelf is just common sense > > Restricting yourself to components which you can buy cheaply off the > shelf rather narrows your range, particularly when it comes to > transformers. >Oh, I don't know about that. A big PSU or one with special requirements might well need custom magnetics, and it probably pays to micro-optimize high volume designs. For annual quantities of tens to hundreds, though, (where John lives and I aspire to) ;) the performance advantage probably doesn't pay for the increased pain in procurement. SMPSes can be fun once in awhile, but doing vanilla ones as a steady diet must be booooorrrinnnggg. Cheers Phil Hobbs -- Dr Philip C D Hobbs Principal Consultant ElectroOptical Innovations LLC Optics, Electro-optics, Photonics, Analog Electronics 160 North State Road #203 Briarcliff Manor NY 10510 hobbs at electrooptical dot net http://electrooptical.net
Reply by ●July 21, 20152015-07-21
On Tue, 21 Jul 2015 11:52:23 -0400, Phil Hobbs <pcdhSpamMeSenseless@electrooptical.net> wrote:>On 07/21/2015 11:46 AM, Bill Sloman wrote: >> On Tuesday, July 21, 2015 at 12:38:07 AM UTC+2, Lasse Langwadt >> Christensen wrote: >>> Den mandag den 20. juli 2015 kl. 17.24.11 UTC+2 skrev Bill Sloman: >>>> On Sunday, July 19, 2015 at 7:40:19 PM UTC+2, John Larkin wrote: >>>>> On Sat, 18 Jul 2015 19:53:31 -0400, M Philbrook >>>>> <jamie_ka1lpa@charter.net> wrote: >>>>> >>>>>> In article >>>>>> <c228b7df-ec64-469a-ae5f-f4ae29cfe028@googlegroups.com>, >>>>>> bill.sloman@gmail.com says... >>>>>>> >>>>>>> On Saturday, July 18, 2015 at 5:50:11 PM UTC+2, John Larkin >>>>>>> wrote: >>>>>>>> On Sat, 18 Jul 2015 09:39:34 -0400, bitrex >>>>>>>> <bitrex@de.lete.earthlink.net> wrote: >>>>>>>> >>>>>>>>> >>>>>>>>> For a hobby project, I'd like to be able to generate >>>>>>>>> +48 volts or so from +5 volt USB. Current requirements >>>>>>>>> are small, maybe 15 mA or so? I'd like uh, low noise (I >>>>>>>>> don't have an exact spec so this is just kind of >>>>>>>>> existential at this point), so maybe a charge pump >>>>>>>>> would be in order rather than a boost switcher? >>>>>>>>> >>>>>>>>> Does anyone make a charge pump IC that I could feed an >>>>>>>>> external clock to, with outputs suitable for running >>>>>>>>> something like a Dickson pump? Maybe that would be too >>>>>>>>> many stages to go from +5 to +48... >>>>>>>> >>>>>>>> Two of these >>>>>>>> >>>>>>>> http://www.digikey.com/product-detail/en/PDS1-S5-S24-M-TR/102-2973-2-ND/4006941 >>>>>>>> >>>>>>>> >>>>>>>> >with the outputs in series would work. They are fairly quiet, and you >>>>>>>> could add a little filtering to help. At light loads, >>>>>>>> their output tends to be a few per cent high. But then, 5 >>>>>>>> volts from USB may not really be 5 volts. >>>>>>>> >>>>>>>> For really quiet, consider some sort of sinewave drive >>>>>>>> step-up transformer. >>>>>>> >>>>>>> A Baxandall Class-D oscillator - one step-up transformer >>>>>>> and one inductor - would work well. MOS-FET transistors do >>>>>>> a bit better than bipolar transistors, but Baxandall's >>>>>>> paper rather pre-dates them. >>>>>>> >>>>>>> http://sophia-elektronica.com/0344_001_Baxandal.pdf >>>>>>> >>>>>>> http://sophia-elektronica.com/Baxandall_parallel-resonant_Class-D_oscillator1.htm >>>>>> >>>>>> >>>>>>> >Oh God, You just couldn't keep that failed OSC out of th subject! >>>>> >>>>> It's an interesting circuit from a time scaling standpoint. It >>>>> will oscillate at tens of KHz, but it takes decades to build. >>>> >>>> John Larkin is too dim to notice the difference between a low >>>> distortion oscillator and the Baxandall/Jim Williams oscillator. >>> >>> Though it can hardly come as a surprise that you get teased about >>> it since you have been talking about for years and still haven't >>> gotten around to building it, as if a bit of table space for a >>> soldering iron and time, for someone who doesn't have to go to work >>> everyday, is impossible to find. >> >> I'd gotten most of the way to building an example - bought all the >> parts, including getting the specially wound transformers - a few >> years ago, just before I moved back to Australia, which gave me >> enough time to think up a better variation, which I may get built >> real soon now, if I'm lucky. >> >> It's not got much to do with Baxandall's class-D oscillator (though >> my variant of that is what got me started) but Jamie and John are too >> dim to make that kind of fine distinction. >> >>>> "The circuit is probably best known from Jim Williams' series of >>>> application notes for Linear Technology, on high frequency >>>> inverters for driving cold cathode back-lights used in laptop >>>> computers (application notes AN45, AN49, AN51, AN55, AN61, >>>> AN65)." These apparently were Linear Technology's most popular >>>> application notes for quite a while. >>>> >>>> Nobody has had any trouble building them in jig time. Except >>>> perhaps John Larkin, who can't cope with transformers that he >>>> can't buy off the shelf.. >>>> >>> >>> Aiming to build stuff from things you can get cheap and fast off >>> the shelf is just common sense >> >> Restricting yourself to components which you can buy cheaply off the >> shelf rather narrows your range, particularly when it comes to >> transformers. >> > >Oh, I don't know about that. A big PSU or one with special requirements >might well need custom magnetics, and it probably pays to micro-optimize >high volume designs. For annual quantities of tens to hundreds, though, >(where John lives and I aspire to) ;) the performance advantage probably >doesn't pay for the increased pain in procurement.Custom magnetics is a real pain. Winding them yourself is crazy; they will wind up costing ten or more times what a commercial surface-mount part would cost. Just a bobbin will cost more than an entire finished inductor. Ordering them from a magnetics house takes weeks of waiting and a lot of engineering work documenting the part. It can take a little ingenuity to make a circuit from standard parts, but there are tons of standard inductors available too. There's seldom a justification for building an off-line switcher. Things like wall-warts and MeanWell bricks are absurdly cheap and have all the UL/CE/FCC stickers you would ever want.> >SMPSes can be fun once in awhile, but doing vanilla ones as a steady >diet must be booooorrrinnnggg.There are lots of interesting packaged switchers around these days, like 7805 drop-in replacements, hybrid bucks with magnetics and caps, tiny dc/dc converters; they tend to cluster in the $4 range. It's seldom worth even the parts cost of making your own standard switcher; well, some small synchronous bucks aren't too bad, like to go from +5 to +1.2 or something. Time to move up the abstraction stack. -- John Larkin Highland Technology, Inc lunatic fringe electronics jlarkin att highlandtechnology dott com http://www.highlandtechnology.com
Reply by ●July 21, 20152015-07-21
On Tuesday, July 21, 2015 at 5:52:30 PM UTC+2, Phil Hobbs wrote:> On 07/21/2015 11:46 AM, Bill Sloman wrote: > > On Tuesday, July 21, 2015 at 12:38:07 AM UTC+2, Lasse Langwadt > > Christensen wrote: > >> Den mandag den 20. juli 2015 kl. 17.24.11 UTC+2 skrev Bill Sloman: > >>> On Sunday, July 19, 2015 at 7:40:19 PM UTC+2, John Larkin wrote: > >>>> On Sat, 18 Jul 2015 19:53:31 -0400, M Philbrook > >>>> <jamie_ka1lpa@charter.net> wrote: > >>>> > >>>>> In article > >>>>> <c228b7df-ec64-469a-ae5f-f4ae29cfe028@googlegroups.com>, > >>>>> bill.sloman@gmail.com says... > >>>>>> > >>>>>> On Saturday, July 18, 2015 at 5:50:11 PM UTC+2, John Larkin > >>>>>> wrote: > >>>>>>> On Sat, 18 Jul 2015 09:39:34 -0400, bitrex > >>>>>>> <bitrex@de.lete.earthlink.net> wrote: > >>>>>>> > >>>>>>>> > >>>>>>>> For a hobby project, I'd like to be able to generate > >>>>>>>> +48 volts or so from +5 volt USB. Current requirements > >>>>>>>> are small, maybe 15 mA or so? I'd like uh, low noise (I > >>>>>>>> don't have an exact spec so this is just kind of > >>>>>>>> existential at this point), so maybe a charge pump > >>>>>>>> would be in order rather than a boost switcher? > >>>>>>>> > >>>>>>>> Does anyone make a charge pump IC that I could feed an > >>>>>>>> external clock to, with outputs suitable for running > >>>>>>>> something like a Dickson pump? Maybe that would be too > >>>>>>>> many stages to go from +5 to +48... > >>>>>>> > >>>>>>> Two of these > >>>>>>> > >>>>>>> http://www.digikey.com/product-detail/en/PDS1-S5-S24-M-TR/102-2973-2-ND/4006941 > >>>>>>> > >>>>>>> > >>>>>>> > with the outputs in series would work. They are fairly quiet, and you > >>>>>>> could add a little filtering to help. At light loads, > >>>>>>> their output tends to be a few per cent high. But then, 5 > >>>>>>> volts from USB may not really be 5 volts. > >>>>>>> > >>>>>>> For really quiet, consider some sort of sinewave drive > >>>>>>> step-up transformer. > >>>>>> > >>>>>> A Baxandall Class-D oscillator - one step-up transformer > >>>>>> and one inductor - would work well. MOS-FET transistors do > >>>>>> a bit better than bipolar transistors, but Baxandall's > >>>>>> paper rather pre-dates them. > >>>>>> > >>>>>> http://sophia-elektronica.com/0344_001_Baxandal.pdf > >>>>>> > >>>>>> http://sophia-elektronica.com/Baxandall_parallel-resonant_Class-D_oscillator1.htm > >>>>> > >>>>> > >>>>>> > Oh God, You just couldn't keep that failed OSC out of th subject! > >>>> > >>>> It's an interesting circuit from a time scaling standpoint. It > >>>> will oscillate at tens of KHz, but it takes decades to build. > >>> > >>> John Larkin is too dim to notice the difference between a low > >>> distortion oscillator and the Baxandall/Jim Williams oscillator. > >> > >> Though it can hardly come as a surprise that you get teased about > >> it since you have been talking about for years and still haven't > >> gotten around to building it, as if a bit of table space for a > >> soldering iron and time, for someone who doesn't have to go to work > >> everyday, is impossible to find. > > > > I'd gotten most of the way to building an example - bought all the > > parts, including getting the specially wound transformers - a few > > years ago, just before I moved back to Australia, which gave me > > enough time to think up a better variation, which I may get built > > real soon now, if I'm lucky. > > > > It's not got much to do with Baxandall's class-D oscillator (though > > my variant of that is what got me started) but Jamie and John are too > > dim to make that kind of fine distinction. > > > >>> "The circuit is probably best known from Jim Williams' series of > >>> application notes for Linear Technology, on high frequency > >>> inverters for driving cold cathode back-lights used in laptop > >>> computers (application notes AN45, AN49, AN51, AN55, AN61, > >>> AN65)." These apparently were Linear Technology's most popular > >>> application notes for quite a while. > >>> > >>> Nobody has had any trouble building them in jig time. Except > >>> perhaps John Larkin, who can't cope with transformers that he > >>> can't buy off the shelf.. > >>> > >> > >> Aiming to build stuff from things you can get cheap and fast off > >> the shelf is just common sense > > > > Restricting yourself to components which you can buy cheaply off the > > shelf rather narrows your range, particularly when it comes to > > transformers. > > Oh, I don't know about that.Then you probably need to learn a bit more about the ranges of cores and formers available off the shelf.> A big PSU or one with special requirements > might well need custom magnetics, and it probably pays to micro-optimize > high volume designs. For annual quantities of tens to hundreds, though, > (where John lives and I aspire to) ;) the performance advantage probably > doesn't pay for the increased pain in procurement. > > SMPSes can be fun once in awhile, but doing vanilla ones as a steady > diet must be booooorrrinnnggg.Obviously. But neither you nor John do much of that. Transformers and inductors offer rather a lot of variables, so getting one right for a particular application isn't "micro-optimisation". John Larkin wanted a tune-able inductor which he could have had wound onto an off-the-shelf former for an off-the-shelf core that came with a tuning slug (I gave him links to both), but he found that too hard. Transformers for low volume production aren't mass-produced, and there are plenty of small winding shop that will make them for you pretty cheaply, or at least wind the wire onto formers. They'll probably clip the cores around the wound formers for very little more. -- Bill Sloman, Sydney
Reply by ●July 21, 20152015-07-21
Den tirsdag den 21. juli 2015 kl. 18.21.55 UTC+2 skrev John Larkin:> On Tue, 21 Jul 2015 11:52:23 -0400, Phil Hobbs > <pcdhSpamMeSenseless@electrooptical.net> wrote: > > >On 07/21/2015 11:46 AM, Bill Sloman wrote: > >> On Tuesday, July 21, 2015 at 12:38:07 AM UTC+2, Lasse Langwadt > >> Christensen wrote: > >>> Den mandag den 20. juli 2015 kl. 17.24.11 UTC+2 skrev Bill Sloman: > >>>> On Sunday, July 19, 2015 at 7:40:19 PM UTC+2, John Larkin wrote: > >>>>> On Sat, 18 Jul 2015 19:53:31 -0400, M Philbrook > >>>>> <jamie_ka1lpa@charter.net> wrote: > >>>>> > >>>>>> In article > >>>>>> <c228b7df-ec64-469a-ae5f-f4ae29cfe028@googlegroups.com>, > >>>>>> bill.sloman@gmail.com says... > >>>>>>> > >>>>>>> On Saturday, July 18, 2015 at 5:50:11 PM UTC+2, John Larkin > >>>>>>> wrote: > >>>>>>>> On Sat, 18 Jul 2015 09:39:34 -0400, bitrex > >>>>>>>> <bitrex@de.lete.earthlink.net> wrote: > >>>>>>>> > >>>>>>>>> > >>>>>>>>> For a hobby project, I'd like to be able to generate > >>>>>>>>> +48 volts or so from +5 volt USB. Current requirements > >>>>>>>>> are small, maybe 15 mA or so? I'd like uh, low noise (I > >>>>>>>>> don't have an exact spec so this is just kind of > >>>>>>>>> existential at this point), so maybe a charge pump > >>>>>>>>> would be in order rather than a boost switcher? > >>>>>>>>> > >>>>>>>>> Does anyone make a charge pump IC that I could feed an > >>>>>>>>> external clock to, with outputs suitable for running > >>>>>>>>> something like a Dickson pump? Maybe that would be too > >>>>>>>>> many stages to go from +5 to +48... > >>>>>>>> > >>>>>>>> Two of these > >>>>>>>> > >>>>>>>> http://www.digikey.com/product-detail/en/PDS1-S5-S24-M-TR/102-2973-2-ND/4006941 > >>>>>>>> > >>>>>>>> > >>>>>>>> > >with the outputs in series would work. They are fairly quiet, and you > >>>>>>>> could add a little filtering to help. At light loads, > >>>>>>>> their output tends to be a few per cent high. But then, 5 > >>>>>>>> volts from USB may not really be 5 volts. > >>>>>>>> > >>>>>>>> For really quiet, consider some sort of sinewave drive > >>>>>>>> step-up transformer. > >>>>>>> > >>>>>>> A Baxandall Class-D oscillator - one step-up transformer > >>>>>>> and one inductor - would work well. MOS-FET transistors do > >>>>>>> a bit better than bipolar transistors, but Baxandall's > >>>>>>> paper rather pre-dates them. > >>>>>>> > >>>>>>> http://sophia-elektronica.com/0344_001_Baxandal.pdf > >>>>>>> > >>>>>>> http://sophia-elektronica.com/Baxandall_parallel-resonant_Class-D_oscillator1.htm > >>>>>> > >>>>>> > >>>>>>> > >Oh God, You just couldn't keep that failed OSC out of th subject! > >>>>> > >>>>> It's an interesting circuit from a time scaling standpoint. It > >>>>> will oscillate at tens of KHz, but it takes decades to build. > >>>> > >>>> John Larkin is too dim to notice the difference between a low > >>>> distortion oscillator and the Baxandall/Jim Williams oscillator. > >>> > >>> Though it can hardly come as a surprise that you get teased about > >>> it since you have been talking about for years and still haven't > >>> gotten around to building it, as if a bit of table space for a > >>> soldering iron and time, for someone who doesn't have to go to work > >>> everyday, is impossible to find. > >> > >> I'd gotten most of the way to building an example - bought all the > >> parts, including getting the specially wound transformers - a few > >> years ago, just before I moved back to Australia, which gave me > >> enough time to think up a better variation, which I may get built > >> real soon now, if I'm lucky. > >> > >> It's not got much to do with Baxandall's class-D oscillator (though > >> my variant of that is what got me started) but Jamie and John are too > >> dim to make that kind of fine distinction. > >> > >>>> "The circuit is probably best known from Jim Williams' series of > >>>> application notes for Linear Technology, on high frequency > >>>> inverters for driving cold cathode back-lights used in laptop > >>>> computers (application notes AN45, AN49, AN51, AN55, AN61, > >>>> AN65)." These apparently were Linear Technology's most popular > >>>> application notes for quite a while. > >>>> > >>>> Nobody has had any trouble building them in jig time. Except > >>>> perhaps John Larkin, who can't cope with transformers that he > >>>> can't buy off the shelf.. > >>>> > >>> > >>> Aiming to build stuff from things you can get cheap and fast off > >>> the shelf is just common sense > >> > >> Restricting yourself to components which you can buy cheaply off the > >> shelf rather narrows your range, particularly when it comes to > >> transformers. > >> > > > >Oh, I don't know about that. A big PSU or one with special requirements > >might well need custom magnetics, and it probably pays to micro-optimize > >high volume designs. For annual quantities of tens to hundreds, though, > >(where John lives and I aspire to) ;) the performance advantage probably > >doesn't pay for the increased pain in procurement. > > Custom magnetics is a real pain. Winding them yourself is crazy; they > will wind up costing ten or more times what a commercial surface-mount > part would cost. Just a bobbin will cost more than an entire finished > inductor. Ordering them from a magnetics house takes weeks of waiting > and a lot of engineering work documenting the part. > > It can take a little ingenuity to make a circuit from standard parts, > but there are tons of standard inductors available too. > > There's seldom a justification for building an off-line switcher. > Things like wall-warts and MeanWell bricks are absurdly cheap and have > all the UL/CE/FCC stickers you would ever want. > > > > >SMPSes can be fun once in awhile, but doing vanilla ones as a steady > >diet must be booooorrrinnnggg. > > There are lots of interesting packaged switchers around these days, > like 7805 drop-in replacements, hybrid bucks with magnetics and caps, > tiny dc/dc converters; they tend to cluster in the $4 range. It's > seldom worth even the parts cost of making your own standard switcher; > well, some small synchronous bucks aren't too bad, like to go from +5 > to +1.2 or something. > > Time to move up the abstraction stack. >I bough stack of these for prototypes: http://www.ebay.com/itm/171381728637 almost cheaper than buying a 7805 -Lasse
