"bitrex" <bitrex@de.lete.earthlink.net> wrote in message news:55aa97af$0$11862$4c5ecfc7@frugalusenet.com...> On 7/18/2015 10:51 AM, Phil Hobbs wrote: >> On 07/18/2015 10:25 AM, John S wrote: >>> On 7/18/2015 8:39 AM, bitrex 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... >>> >>> My guess is that it would take 11 stages, possibly more. >> >> You can get modules that do most of that for a buck and a half on eBay. >> http://tinyurl.com/q2qkn2u will do 5->24V, and then a homemade >> single-stage charge pump will get you 48V. >> >> Cheers >> >> Phil Hobbs >> > > Oh wow, those are great. They're cheap enough that I could just slap them > into a "finished" product... >They do not have an isolated output. So connecting them in series to make 48 volts will not work.
charge pump/boost converter
Started by ●July 18, 2015
Reply by ●July 18, 20152015-07-18
Reply by ●July 18, 20152015-07-18
On 7/18/2015 2:36 PM, Tom Miller wrote:> > "bitrex" <bitrex@de.lete.earthlink.net> wrote in message > news:55aa97af$0$11862$4c5ecfc7@frugalusenet.com... >> On 7/18/2015 10:51 AM, Phil Hobbs wrote: >>> On 07/18/2015 10:25 AM, John S wrote: >>>> On 7/18/2015 8:39 AM, bitrex 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... >>>> >>>> My guess is that it would take 11 stages, possibly more. >>> >>> You can get modules that do most of that for a buck and a half on eBay. >>> http://tinyurl.com/q2qkn2u will do 5->24V, and then a homemade >>> single-stage charge pump will get you 48V. >>> >>> Cheers >>> >>> Phil Hobbs >>> >> >> Oh wow, those are great. They're cheap enough that I could just slap >> them into a "finished" product... >> > > They do not have an isolated output. So connecting them in series to > make 48 volts will not work. >Right, which is why I suggested the charge pump. Of course the OP could get a buck converter module (about the same dough) and connect it to make -24, then work off the difference. 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 18, 20152015-07-18
On 7/18/2015 1:02 PM, Tim Wescott wrote:> On Sat, 18 Jul 2015 09:39:34 -0400, bitrex 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... > > Boost or flyback, and if noise is an issue then make 50V and follow it > with a linear regulator.Linears only reduce noise in their active bandwidth, often no more than 100 kHz. -- Rick
Reply by ●July 18, 20152015-07-18
On 7/18/2015 3:02 PM, rickman wrote:> On 7/18/2015 1:02 PM, Tim Wescott wrote: >> On Sat, 18 Jul 2015 09:39:34 -0400, bitrex 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... >> >> Boost or flyback, and if noise is an issue then make 50V and follow it >> with a linear regulator. > > Linears only reduce noise in their active bandwidth, often no more than > 100 kHz. >A shunt-regulated cap multiplier can do a _lot_ better. 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 18, 20152015-07-18
"Phil Hobbs" <hobbs@electrooptical.net> wrote in message news:55AAA1D0.1060103@electrooptical.net...> On 7/18/2015 2:36 PM, Tom Miller wrote: >> >> "bitrex" <bitrex@de.lete.earthlink.net> wrote in message >> news:55aa97af$0$11862$4c5ecfc7@frugalusenet.com... >>> On 7/18/2015 10:51 AM, Phil Hobbs wrote: >>>> On 07/18/2015 10:25 AM, John S wrote: >>>>> On 7/18/2015 8:39 AM, bitrex 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... >>>>> >>>>> My guess is that it would take 11 stages, possibly more. >>>> >>>> You can get modules that do most of that for a buck and a half on eBay. >>>> http://tinyurl.com/q2qkn2u will do 5->24V, and then a homemade >>>> single-stage charge pump will get you 48V. >>>> >>>> Cheers >>>> >>>> Phil Hobbs >>>> >>> >>> Oh wow, those are great. They're cheap enough that I could just slap >>> them into a "finished" product... >>> >> >> They do not have an isolated output. So connecting them in series to >> make 48 volts will not work. >> > > Right, which is why I suggested the charge pump. Of course the OP could > get a buck converter module (about the same dough) and connect it to > make -24, then work off the difference. > > 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.netThat's a good idea. Just a diode and capacitor need flipping. And correct the feedback.
Reply by ●July 18, 20152015-07-18
On 7/18/2015 4:04 PM, Tom Miller wrote:> > "Phil Hobbs" <hobbs@electrooptical.net> wrote in message > news:55AAA1D0.1060103@electrooptical.net... >> On 7/18/2015 2:36 PM, Tom Miller wrote: >>> >>> "bitrex" <bitrex@de.lete.earthlink.net> wrote in message >>> news:55aa97af$0$11862$4c5ecfc7@frugalusenet.com... >>>> On 7/18/2015 10:51 AM, Phil Hobbs wrote: >>>>> On 07/18/2015 10:25 AM, John S wrote: >>>>>> On 7/18/2015 8:39 AM, bitrex 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... >>>>>> >>>>>> My guess is that it would take 11 stages, possibly more. >>>>> >>>>> You can get modules that do most of that for a buck and a half on >>>>> eBay. >>>>> http://tinyurl.com/q2qkn2u will do 5->24V, and then a homemade >>>>> single-stage charge pump will get you 48V. >>>>> >>>>> Cheers >>>>> >>>>> Phil Hobbs >>>>> >>>> >>>> Oh wow, those are great. They're cheap enough that I could just slap >>>> them into a "finished" product... >>>> >>> >>> They do not have an isolated output. So connecting them in series to >>> make 48 volts will not work. >>> >> >> Right, which is why I suggested the charge pump. Of course the OP >> could get a buck converter module (about the same dough) and connect >> it to make -24, then work off the difference. >> >> 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 > > That's a good idea. > > Just a diode and capacitor need flipping. > > And correct the feedback. > >Not even. You ground the 'output' pin, and take the negative output from the 'ground' pin. It pumps its 'ground' down by itself. 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 18, 20152015-07-18
On Sat, 18 Jul 2015 15:02:25 -0400, rickman <gnuarm@gmail.com> wrote:>On 7/18/2015 1:02 PM, Tim Wescott wrote: >> On Sat, 18 Jul 2015 09:39:34 -0400, bitrex 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... >> >> Boost or flyback, and if noise is an issue then make 50V and follow it >> with a linear regulator. > >Linears only reduce noise in their active bandwidth, often no more than >100 kHz.That's usually good enough. When it isn't, there are things like TI's LP38798, which extend that another decade or more. After that, use a passive filter.
Reply by ●July 18, 20152015-07-18
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.htmOh God, You just couldn't keep that failed OSC out of th subject! Jamie
Reply by ●July 19, 20152015-07-19
On Saturday, July 18, 2015 at 7:51:24 AM UTC-7, Phil Hobbs wrote:> On 07/18/2015 10:25 AM, John S wrote: > > On 7/18/2015 8:39 AM, bitrex wrote: > >> > >> For a hobby project, I'd like to be able to generate +48 volts or so > >> from +5 volt USB.> You can get modules that do most of that for a buck and a half on eBay. > http://tinyurl.com/q2qkn2u will do 5->24V, and then a homemade > single-stage charge pump will get you 48V.Easier to use a different chip (LM2585 has a slightly different pinout, but almost exactly the same function as that XL6009, and goes to 60V).
Reply by ●July 19, 20152015-07-19
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. -- Bill Sloman, Sydney
