On 03/15/2016 06:16 PM, John Larkin wrote:> On Tue, 15 Mar 2016 14:17:26 -0700 (PDT), mrdarrett@gmail.com wrote: > >> On Tuesday, March 15, 2016 at 1:53:20 PM UTC-7, John Larkin wrote: >>> On Tue, 15 Mar 2016 12:23:29 -0700 (PDT), mrdarrett@gmail.com wrote: >>> >>>> It seems to me that flyback SMPSes use pulsed DC instead of AC. Is this true? >>>> >>>> For example, here, the transistor simply turns on and off, providing pulses to the transformer, right? >>>> >>>> http://www.repairfaq.org/sam/smpsbd.gif >>>> >>>> >>>> Would SMPSes be more efficient if their transformers were fed high-frequency AC instead of high-frequency pulsed DC (for example, by using an H-bridge to provide a negative voltage across the transformer primary for the second half of each cycle)? >>>> >>>> Thanks, >>>> >>>> Michael >>> >>> Really big (like kilowatt) switching supplies are often forward >>> converters, with symmetric square-wave drive, no DC component, into >>> the transformer. No DC in the transformer core is more efficient. >>> >>> http://www.industrial-electronics.com/image/7_33.jpg >>> >>> http://jugandi.com/ebooks/eXe_Power%20Supplies/Power_Supplies/image150a.png >>> >>> https://dl.dropboxusercontent.com/u/53724080/Circuits/ESM/ESM_power_B.pdf >>> >>> >>> There are also some clever resonant designs that run real AC (sine >>> waves) through the magnetics. >>> >>> Small, cheap supplies work well with the flyback topology. >>> >>> >>> -- >>> >>> John Larkin Highland Technology, Inc >>> picosecond timing precision measurement >>> >>> jlarkin att highlandtechnology dott com >>> http://www.highlandtechnology.com >> >> >> Ok, thanks! >> >> Forward Converter... new vocabulary words for today :) >> >> Michael > > > A few more > > Forward > > Flyback > > Buck > > Boost > > Cuk > > Sepic > > Resonant > > Cockroft-Walton > > Royer > > Baxandall > > (there must be more) > >Flybuck ICL7660-style flying capacitor Tesla coil thunderstorm ;) Cheers Phil Hobbs
smps: AC or pulsed DC fed into transformer?
Started by ●March 15, 2016
Reply by ●March 15, 20162016-03-15
Reply by ●March 16, 20162016-03-16
On 2016-03-15, mrdarrett@gmail.com <mrdarrett@gmail.com> wrote:> It seems to me that flyback SMPSes use pulsed DC instead of AC. Is this true?yes.> For example, here, the transistor simply turns on and off, providing pulses to the transformer, right?It's not a transformer... it's an inductor with two windings.> http://www.repairfaq.org/sam/smpsbd.gif> Would SMPSes be more efficient if their transformers were fed > high-frequency AC instead of high-frequency pulsed DC (for example, by > using an H-bridge to provide a negative voltage across the transformer > primary for the second half of each cycle)?That won't work with a flyback, but with a forwards converter* it would work, but now you have twice the switch losses. (*) where the secondary and primary windings conduct simultaneously eg: Royer. -- \_(ツ)_
Reply by ●March 16, 20162016-03-16
On 2016-03-15, mrdarrett@gmail.com <mrdarrett@gmail.com> wrote:> On Tuesday, March 15, 2016 at 1:53:20 PM UTC-7, John Larkin wrote: >> On Tue, 15 Mar 2016 12:23:29 -0700 (PDT), mrdarrett@gmail.com wrote: >> >> >It seems to me that flyback SMPSes use pulsed DC instead of AC. Is this true? >> > >> >For example, here, the transistor simply turns on and off, providing pulses to the transformer, right? >> > >> >http://www.repairfaq.org/sam/smpsbd.gif >> > >> > >> >Would SMPSes be more efficient if their transformers were fed high-frequency AC instead of high-frequency pulsed DC (for example, by using an H-bridge to provide a negative voltage across the transformer primary for the second half of each cycle)? >> > >> >Thanks, >> > >> >Michael >> >> Really big (like kilowatt) switching supplies are often forward >> converters, with symmetric square-wave drive, no DC component, into >> the transformer. No DC in the transformer core is more efficient. >> >> http://www.industrial-electronics.com/image/7_33.jpg >> >> http://jugandi.com/ebooks/eXe_Power%20Supplies/Power_Supplies/image150a.png >> >> https://dl.dropboxusercontent.com/u/53724080/Circuits/ESM/ESM_power_B.pdf >> >> >> There are also some clever resonant designs that run real AC (sine >> waves) through the magnetics. >> >> Small, cheap supplies work well with the flyback topology. >> >> >> -- >> >> John Larkin Highland Technology, Inc >> picosecond timing precision measurement >> >> jlarkin att highlandtechnology dott com >> http://www.highlandtechnology.com > > > Ok, thanks! > > Forward Converter... new vocabulary words for today :)A good intro to switched mode: http://www.onsemi.com/pub_link/Collateral/SMPSRM-D.PDF -- \_(ツ)_
Reply by ●March 16, 20162016-03-16
On Wednesday, March 16, 2016 at 1:00:58 AM UTC-7, Jasen Betts wrote:> On 2016-03-15, mrdarrett@gmail.com <mrdarrett@gmail.com> wrote: > > On Tuesday, March 15, 2016 at 1:53:20 PM UTC-7, John Larkin wrote: > >> On Tue, 15 Mar 2016 12:23:29 -0700 (PDT), mrdarrett@gmail.com wrote: > >> > >> >It seems to me that flyback SMPSes use pulsed DC instead of AC. Is this true? > >> > > >> >For example, here, the transistor simply turns on and off, providing pulses to the transformer, right? > >> > > >> >http://www.repairfaq.org/sam/smpsbd.gif > >> > > >> > > >> >Would SMPSes be more efficient if their transformers were fed high-frequency AC instead of high-frequency pulsed DC (for example, by using an H-bridge to provide a negative voltage across the transformer primary for the second half of each cycle)? > >> > > >> >Thanks, > >> > > >> >Michael > >> > >> Really big (like kilowatt) switching supplies are often forward > >> converters, with symmetric square-wave drive, no DC component, into > >> the transformer. No DC in the transformer core is more efficient. > >> > >> http://www.industrial-electronics.com/image/7_33.jpg > >> > >> http://jugandi.com/ebooks/eXe_Power%20Supplies/Power_Supplies/image150a.png > >> > >> https://dl.dropboxusercontent.com/u/53724080/Circuits/ESM/ESM_power_B.pdf > >> > >> > >> There are also some clever resonant designs that run real AC (sine > >> waves) through the magnetics. > >> > >> Small, cheap supplies work well with the flyback topology. > >> > >> > >> -- > >> > >> John Larkin Highland Technology, Inc > >> picosecond timing precision measurement > >> > >> jlarkin att highlandtechnology dott com > >> http://www.highlandtechnology.com > > > > > > Ok, thanks! > > > > Forward Converter... new vocabulary words for today :) > > A good intro to switched mode: > > http://www.onsemi.com/pub_link/Collateral/SMPSRM-D.PDF > > -- > \_(ツ)_Ooh thanks! Michael
Reply by ●March 16, 20162016-03-16
"Phil Hobbs" <pcdhSpamMeSenseless@electrooptical.net> wrote in message news:ubKdnYuZLqFYCXXLnZ2dnUU7-TOdnZ2d@supernews.com...> On 03/15/2016 06:16 PM, John Larkin wrote: >> On Tue, 15 Mar 2016 14:17:26 -0700 (PDT), mrdarrett@gmail.com wrote: >> >>> On Tuesday, March 15, 2016 at 1:53:20 PM UTC-7, John Larkin wrote: >>>> On Tue, 15 Mar 2016 12:23:29 -0700 (PDT), mrdarrett@gmail.com wrote: >>>> >>>>> It seems to me that flyback SMPSes use pulsed DC instead of AC. Is >>>>> this true? >>>>> >>>>> For example, here, the transistor simply turns on and off, providing >>>>> pulses to the transformer, right? >>>>> >>>>> http://www.repairfaq.org/sam/smpsbd.gif >>>>> >>>>> >>>>> Would SMPSes be more efficient if their transformers were fed >>>>> high-frequency AC instead of high-frequency pulsed DC (for example, by >>>>> using an H-bridge to provide a negative voltage across the transformer >>>>> primary for the second half of each cycle)? >>>>> >>>>> Thanks, >>>>> >>>>> Michael >>>> >>>> Really big (like kilowatt) switching supplies are often forward >>>> converters, with symmetric square-wave drive, no DC component, into >>>> the transformer. No DC in the transformer core is more efficient. >>>> >>>> http://www.industrial-electronics.com/image/7_33.jpg >>>> >>>> http://jugandi.com/ebooks/eXe_Power%20Supplies/Power_Supplies/image150a.png >>>> >>>> https://dl.dropboxusercontent.com/u/53724080/Circuits/ESM/ESM_power_B.pdf >>>> >>>> >>>> There are also some clever resonant designs that run real AC (sine >>>> waves) through the magnetics. >>>> >>>> Small, cheap supplies work well with the flyback topology. >>>> >>>> >>>> -- >>>> >>>> John Larkin Highland Technology, Inc >>>> picosecond timing precision measurement >>>> >>>> jlarkin att highlandtechnology dott com >>>> http://www.highlandtechnology.com >>> >>> >>> Ok, thanks! >>> >>> Forward Converter... new vocabulary words for today :) >>> >>> Michael >> >> >> A few more >> >> Forward >> >> Flyback >> >> Buck >> >> Boost >> >> Cuk >> >> Sepic >> >> Resonant >> >> Cockroft-Walton >> >> Royer >> >> Baxandall >> >> (there must be more) >> >> > > Flybuck > > ICL7660-style flying capacitor > > Tesla coil > > thunderstorm ;)I'd be interested to see a 6MV supercapacitor and a buck that can bring that down to national grid type voltages. Apparently US power companies have for some time been experimenting with EHV DC distribution lines. Last I heard they were reaching for 1MV in an attempt to find the tradeoff between corona discharge on EHV DC compared to capacitive losses on lower voltage AC distribution.
Reply by ●March 16, 20162016-03-16
On Tue, 15 Mar 2016 19:03:33 -0400, Phil Hobbs <pcdhSpamMeSenseless@electrooptical.net> wrote:>On 03/15/2016 06:16 PM, John Larkin wrote: >> On Tue, 15 Mar 2016 14:17:26 -0700 (PDT), mrdarrett@gmail.com wrote: >> >>> On Tuesday, March 15, 2016 at 1:53:20 PM UTC-7, John Larkin wrote: >>>> On Tue, 15 Mar 2016 12:23:29 -0700 (PDT), mrdarrett@gmail.com wrote: >>>> >>>>> It seems to me that flyback SMPSes use pulsed DC instead of AC. Is this true? >>>>> >>>>> For example, here, the transistor simply turns on and off, providing pulses to the transformer, right? >>>>> >>>>> http://www.repairfaq.org/sam/smpsbd.gif >>>>> >>>>> >>>>> Would SMPSes be more efficient if their transformers were fed high-frequency AC instead of high-frequency pulsed DC (for example, by using an H-bridge to provide a negative voltage across the transformer primary for the second half of each cycle)? >>>>> >>>>> Thanks, >>>>> >>>>> Michael >>>> >>>> Really big (like kilowatt) switching supplies are often forward >>>> converters, with symmetric square-wave drive, no DC component, into >>>> the transformer. No DC in the transformer core is more efficient. >>>> >>>> http://www.industrial-electronics.com/image/7_33.jpg >>>> >>>> http://jugandi.com/ebooks/eXe_Power%20Supplies/Power_Supplies/image150a.png >>>> >>>> https://dl.dropboxusercontent.com/u/53724080/Circuits/ESM/ESM_power_B.pdf >>>> >>>> >>>> There are also some clever resonant designs that run real AC (sine >>>> waves) through the magnetics. >>>> >>>> Small, cheap supplies work well with the flyback topology. >>>> >>>> >>>> -- >>>> >>>> John Larkin Highland Technology, Inc >>>> picosecond timing precision measurement >>>> >>>> jlarkin att highlandtechnology dott com >>>> http://www.highlandtechnology.com >>> >>> >>> Ok, thanks! >>> >>> Forward Converter... new vocabulary words for today :) >>> >>> Michael >> >> >> A few more >> >> Forward >> >> Flyback >> >> Buck >> >> Boost >> >> Cuk >> >> Sepic >> >> Resonant >> >> Cockroft-Walton >> >> Royer >> >> Baxandall >> >> (there must be more) >> >> > >Flybuck > >ICL7660-style flying capacitorI think LTC or somebody makes what is basically a flying-inductor converter. -- John Larkin Highland Technology, Inc picosecond timing precision measurement jlarkin att highlandtechnology dott com http://www.highlandtechnology.com
Reply by ●March 18, 20162016-03-18
"Helmut Wabnig" <hwabnig@.- --- -.dotat> napisal w wiadomosci news:0iqgeb9fhj643eqvbeti4b8nkmtrc830sb@4ax.com...> On Tue, 15 Mar 2016 12:23:29 -0700 (PDT), mrdarrett@gmail.com wrote: > >>It seems to me that flyback SMPSes use pulsed DC instead of AC. Is this >>true? >> >>For example, here, the transistor simply turns on and off, providing >>pulses to the transformer, right? >> >>http://www.repairfaq.org/sam/smpsbd.gif >> >> >>Would SMPSes be more efficient if their transformers were fed >>high-frequency AC instead of high-frequency pulsed DC (for example, by >>using an H-bridge to provide a negative voltage across the transformer >>primary for the second half of each cycle)? >> >>Thanks, >> >>Michael > > High Frequency chopped DC is equal to High Frequency AC.It is true.> > I.T. I.S. A.C.But "Alternating current (AC), is an electric current in which the flow of electric charge periodically reverses direction, whereas in direct current (DC, also dc), the flow of electric charge is only in one direction". So the High Frequency AC which is flowing in a transmising line is not AC at all. It is the impulsing current. Do you agree? S*
Reply by ●March 18, 20162016-03-18
<mrdarrett@gmail.com> napisal w wiadomosci news:41831c05-fc32-4e3f-942c-38ec697932a6@googlegroups.com...> It seems to me that flyback SMPSes use pulsed DC instead of AC. Is this > true? > > For example, here, the transistor simply turns on and off, providing > pulses to the transformer, right? > > http://www.repairfaq.org/sam/smpsbd.gif > > > Would SMPSes be more efficient if their transformers were fed > high-frequency AC instead of high-frequency pulsed DC (for example, by > using an H-bridge to provide a negative voltage across the transformer > primary for the second half of each cycle)? >https://en.wikipedia.org/wiki/File:Types_of_current.svg Your flyback is using the impulsing current. But the term "impulsing current" was used by Tesla. Up to now the Tesla name is absent in textbooks about radio. Do You know that Tesla was "Father of radio": http://www.tfcbooks.com/tesla/1929-09-22.htm S(
Reply by ●May 17, 20162016-05-17
On Tuesday, March 15, 2016 at 4:05:16 PM UTC-4, Helmut Wabnig wrote:> On Tue, 15 Mar 2016 12:23:29 -0700 (PDT), mrdarrett@gmail.com wrote: > > >It seems to me that flyback SMPSes use pulsed DC instead of AC. Is this true? > > > >For example, here, the transistor simply turns on and off, providing pulses to the transformer, right? > > > >http://www.repairfaq.org/sam/smpsbd.gif > > > > > >Would SMPSes be more efficient if their transformers were fed high-frequency AC instead of high-frequency pulsed DC (for example, by using an H-bridge to provide a negative voltage across the transformer primary for the second half of each cycle)? > > > >Thanks, > > > >Michael > > High Frequency chopped DC is equal to High Frequency AC. > > I.T. I.S. A.C. > > w.I disagree. AC REVERSES polarity (hence the "Alternating" in Alternating Current). Pulsed DC does not.
Reply by ●May 18, 20162016-05-18
"repurplecirculation" <dave@beefydog.com> napisa� w wiadomo�ci news:1e55c872-29ab-44a3-a021-a178a49fc1a8@googlegroups.com...> On Tuesday, March 15, 2016 at 4:05:16 PM UTC-4, Helmut Wabnig wrote: >> On Tue, 15 Mar 2016 12:23:29 -0700 (PDT), mrdarrett@gmail.com wrote: >> >> >It seems to me that flyback SMPSes use pulsed DC instead of AC. Is this >> >true? >> > >> >For example, here, the transistor simply turns on and off, providing >> >pulses to the transformer, right? >> > >> >http://www.repairfaq.org/sam/smpsbd.gif >> > >> > >> >Would SMPSes be more efficient if their transformers were fed >> >high-frequency AC instead of high-frequency pulsed DC (for example, by >> >using an H-bridge to provide a negative voltage across the transformer >> >primary for the second half of each cycle)? >> > >> >Thanks, >> > >> >Michael >> >> High Frequency chopped DC is equal to High Frequency AC. >> >> I.T. I.S. A.C. >> >> w. > > I disagree. AC REVERSES polarity (hence the "Alternating" in Alternating > Current). Pulsed DC does not.Sometimes names are not precise. The High Frequency AC in the radio mast is not symetric AC. So it is practically the Pulsed DC. S*
