On Thu, 5 Aug 2021 18:05:45 -0700, John Robertson <spam@flippers.com> wrote:> >I have a trick on-topic question, looking for possibilities for >candidates for a 16-pin SMD device that has these pin outs identified so >far: > >1 & 16 - RC oscillator > >4 - ground > >7 & 8 - drivers for a "H" style MOSFet set of four transistors that >between them generate a modified sine wave running at 60Hz and 120V. > >So it is NOT a TI SG3524/3525 chip. > >The MOSFets generate the power from the output of a small 12V to 120VAC >switching transformer which generates the raw 120VDC or so source for >the modified sine wave output. The transformer also appears to be driven >by the IC in question above via another pair of MOSFets. Or it may >simply be a relaxation oscillator with feedback whose job is simply to >keep the output at 120VDC load or no load. If overloaded I expect is >simply shuts down. > >Why am I doing this you may ask? > >I want to identify the IC so I can make the output frequency adjustable >without changing the output voltage - this has applications in my >jukebox field you see... > >Why not simply make my own adjustable inverter? Well, this unit is >cheap, already in a package with a fan, and is rather common I suspect - >so easy for me to buy up a few to see if there actually is a market for >my idea. If there isn't I'm only out a few hours of time and a few >hundred dollars at most in parts. If this works then I'll go the design >route and make something chat I can scrape the numbers off... > >Thanks for any suggestions of ICs to consider, > >John :-#)#I took a brief look. Didn't find your part, sorry, but found a nifty little ASIC from a Chinese company that works as a true sine wave controller. Unipolar or bipolar modulation and either handles the stuff after the 400V bus is created or can do the whole shebang with a low frequency transformer. -- Best regards, Spehro Pefhany
Trying to identify SMD with label scrubbed off - PWM, inverter, 100W 12VDC to 120VAC modified sine wave
Started by ●August 5, 2021
Reply by ●August 7, 20212021-08-07
Reply by ●August 7, 20212021-08-07
On 8/8/21 5:39 am, Spehro Pefhany wrote:> On Thu, 5 Aug 2021 18:05:45 -0700, John Robertson <spam@flippers.com> > wrote: > >> >> I have a trick on-topic question, looking for possibilities for >> candidates for a 16-pin SMD device that has these pin outs identified so >> far: >> >> 1 & 16 - RC oscillator >> >> 4 - ground >> >> 7 & 8 - drivers for a "H" style MOSFet set of four transistors that >> between them generate a modified sine wave running at 60Hz and 120V. >> >> So it is NOT a TI SG3524/3525 chip. >> >> The MOSFets generate the power from the output of a small 12V to 120VAC >> switching transformer which generates the raw 120VDC or so source for >> the modified sine wave output. The transformer also appears to be driven >> by the IC in question above via another pair of MOSFets. Or it may >> simply be a relaxation oscillator with feedback whose job is simply to >> keep the output at 120VDC load or no load. If overloaded I expect is >> simply shuts down. >> >> Why am I doing this you may ask? >> >> I want to identify the IC so I can make the output frequency adjustable >> without changing the output voltage - this has applications in my >> jukebox field you see... >> >> Why not simply make my own adjustable inverter? Well, this unit is >> cheap, already in a package with a fan, and is rather common I suspect - >> so easy for me to buy up a few to see if there actually is a market for >> my idea. If there isn't I'm only out a few hours of time and a few >> hundred dollars at most in parts. If this works then I'll go the design >> route and make something chat I can scrape the numbers off... >> >> Thanks for any suggestions of ICs to consider, >> >> John :-#)# > > I took a brief look. Didn't find your part, sorry, but found a nifty > little ASIC from a Chinese company that works as a true sine wave > controller. Unipolar or bipolar modulation and either handles the > stuff after the 400V bus is created or can do the whole shebang with a > low frequency transformer.Tease! Part numbers or it didn't happen :)
Reply by ●August 7, 20212021-08-07
On Sun, 8 Aug 2021 11:02:20 +1000, Clifford Heath <no.spam@please.net> wrote:>On 8/8/21 5:39 am, Spehro Pefhany wrote: >> On Thu, 5 Aug 2021 18:05:45 -0700, John Robertson <spam@flippers.com> >> wrote: >> >>> >>> I have a trick on-topic question, looking for possibilities for >>> candidates for a 16-pin SMD device that has these pin outs identified so >>> far: >>> >>> 1 & 16 - RC oscillator >>> >>> 4 - ground >>> >>> 7 & 8 - drivers for a "H" style MOSFet set of four transistors that >>> between them generate a modified sine wave running at 60Hz and 120V. >>> >>> So it is NOT a TI SG3524/3525 chip. >>> >>> The MOSFets generate the power from the output of a small 12V to 120VAC >>> switching transformer which generates the raw 120VDC or so source for >>> the modified sine wave output. The transformer also appears to be driven >>> by the IC in question above via another pair of MOSFets. Or it may >>> simply be a relaxation oscillator with feedback whose job is simply to >>> keep the output at 120VDC load or no load. If overloaded I expect is >>> simply shuts down. >>> >>> Why am I doing this you may ask? >>> >>> I want to identify the IC so I can make the output frequency adjustable >>> without changing the output voltage - this has applications in my >>> jukebox field you see... >>> >>> Why not simply make my own adjustable inverter? Well, this unit is >>> cheap, already in a package with a fan, and is rather common I suspect - >>> so easy for me to buy up a few to see if there actually is a market for >>> my idea. If there isn't I'm only out a few hours of time and a few >>> hundred dollars at most in parts. If this works then I'll go the design >>> route and make something chat I can scrape the numbers off... >>> >>> Thanks for any suggestions of ICs to consider, >>> >>> John :-#)# >> >> I took a brief look. Didn't find your part, sorry, but found a nifty >> little ASIC from a Chinese company that works as a true sine wave >> controller. Unipolar or bipolar modulation and either handles the >> stuff after the 400V bus is created or can do the whole shebang with a >> low frequency transformer. > > >Tease! Part numbers or it didn't happen :)EG8010 https://www.lz2gl.com/data/power-inverter-3kw/eg8010_datasheet_en.pdf I guess it's a pre-programmed MCU with or without some extra peripherals, but pretty nifty. Sells for a buck and change at LCSC, but they don't have the English datasheet linked. Speaking of parts in that price range, is anyone thinking of using the Rpi chip RP2040 in a real product? -- Best regards, Spehro Pefhany
Reply by ●August 8, 20212021-08-08
On Fri, 6 Aug 2021 22:25:41 -0700 (PDT), Anthony William Sloman <bill.sloman@ieee.org> wrote:>On Saturday, August 7, 2021 at 1:56:14 PM UTC+10, palli...@gmail.com wrote: >> The Slowman fool puked: >> ===================== >> >> >> > The point is that if the current is zero for one third of the time, >> > positive for one third of the time and negative for one third of the time, >> ** Not how real "mod sine" inverters operate. >> There are two requirements on such devices: >> >> 1. Output the normal supply peak voltage. >> >> 2. Output the normal supply RMS voltage. >> >> Using these two, the "off" time must be 50%. >> >> Using only 33% would result in incandescent lamps failing in seconds. > >The standard modified sine wave has an off time of 33% and doesn't blow up incandescent lamps.At what DC input voltage ? The clamp time will depend on battery voltage to regulate the output to the proper RMS voltage. boB> >A regular 240V rms sine wave has a peak voltage of 377V. A modified sine wave would produce 240V rms if the "on" voltages were +/-294 volts. > >If you want to rectify the output (which would be an odd thing to with an inverter) you might set the "on" voltages as high +/-377V. > >I don't know what kind of half-wits you have been dealing with, but you clearly haven't done much thinking about how this gear is used.
Reply by ●August 8, 20212021-08-08
On Sunday, August 8, 2021 at 3:35:37 PM UTC+10, boB wrote:> On Fri, 6 Aug 2021 22:25:41 -0700 (PDT), Anthony William Sloman > <bill....@ieee.org> wrote: > > >On Saturday, August 7, 2021 at 1:56:14 PM UTC+10, palli...@gmail.com wrote: > >> The Slowman fool puked: > >> ===================== > >> >> > >> > The point is that if the current is zero for one third of the time, > >> > positive for one third of the time and negative for one third of the time, > >> ** Not how real "mod sine" inverters operate. > >> There are two requirements on such devices: > >> > >> 1. Output the normal supply peak voltage. > >> > >> 2. Output the normal supply RMS voltage. > >> > >> Using these two, the "off" time must be 50%. > >> > >> Using only 33% would result in incandescent lamps failing in seconds. > > > >The standard modified sine wave has an off time of 33% and doesn't blow up incandescent lamps. > > At what DC input voltage ? The clamp time will depend on battery > voltage to regulate the output to the proper RMS voltage.Not in a modified sine wave converter. You typically use some other system to fix the output voltage. You can play with the off-time to regulate the output power, but as you move away from 33%, off time, the third harmonic content in the output goes up. This doesn't seem to worry Phil, but it does throw away one of the few good points of a pretty crude system. -- Bill Sloman, Sydney
Reply by ●August 8, 20212021-08-08
Some Raving Loony called legg wrote: =======================> > > The peak output voltage on this thing is 120v,** Wot thing ????? Some phantom growing inside your head?> Light bulbs might be the only 'safe' load . . . > > A peak-rectified capacitive load would see this as > being close to drop-out levels, but with almost no > crest factor to sweat it. >** DC to AC supply inverters need to work satisfactorily with all common loads. That is WHY square wave ones are simply NOT in the game. They cannot comply with both the rule I posted. ...... Phil
Reply by ●August 8, 20212021-08-08
On Sun, 8 Aug 2021 01:07:25 -0700 (PDT), Phil Allison <pallison49@gmail.com> wrote:>Some Raving Loony called legg wrote: > >======================= > >> > >> The peak output voltage on this thing is 120v, > >** Wot thing ????? >Bapdas Model MT-MX150W RL
Reply by ●August 9, 20212021-08-09
On Sun, 8 Aug 2021 00:46:06 -0700 (PDT), Anthony William Sloman <bill.sloman@ieee.org> wrote:>On Sunday, August 8, 2021 at 3:35:37 PM UTC+10, boB wrote: >> On Fri, 6 Aug 2021 22:25:41 -0700 (PDT), Anthony William Sloman >> <bill....@ieee.org> wrote: >> >> >On Saturday, August 7, 2021 at 1:56:14 PM UTC+10, palli...@gmail.com wrote: >> >> The Slowman fool puked: >> >> ===================== >> >> >> >> >> > The point is that if the current is zero for one third of the time, >> >> > positive for one third of the time and negative for one third of the time, >> >> ** Not how real "mod sine" inverters operate. >> >> There are two requirements on such devices: >> >> >> >> 1. Output the normal supply peak voltage. >> >> >> >> 2. Output the normal supply RMS voltage. >> >> >> >> Using these two, the "off" time must be 50%. >> >> >> >> Using only 33% would result in incandescent lamps failing in seconds. >> > >> >The standard modified sine wave has an off time of 33% and doesn't blow up incandescent lamps. >> >> At what DC input voltage ? The clamp time will depend on battery >> voltage to regulate the output to the proper RMS voltage. > >Not in a modified sine wave converter. You typically use some other system to fix the output voltage. > >You can play with the off-time to regulate the output power, but as you move away from 33%, off time, the third harmonic content in the output goes up.I suppose you could design a Modified Square Wave inverter to do that but at some point, it might just be as easy to just make a real sinewave. The old 50Hz/60Hz MSW inverters changed the off/clamp time to regulate the output voltage based on load and battery voltage. I worked on them for years. Either way, the distortion is bad, around 30% THD but it is measured slightly different for power waveforms that it is for audio power amps. Similar though. For inverters, only the first 41 or so harmonics matter in the THD specs. boB> >This doesn't seem to worry Phil, but it does throw away one of the few good points of a pretty crude system.
Reply by ●August 9, 20212021-08-09
On Monday, August 9, 2021 at 1:50:37 PM UTC+10, boB wrote:> On Sun, 8 Aug 2021 00:46:06 -0700 (PDT), Anthony William Sloman > <bill....@ieee.org> wrote: > > >On Sunday, August 8, 2021 at 3:35:37 PM UTC+10, boB wrote: > >> On Fri, 6 Aug 2021 22:25:41 -0700 (PDT), Anthony William Sloman > >> <bill....@ieee.org> wrote: > >> > >> >On Saturday, August 7, 2021 at 1:56:14 PM UTC+10, palli...@gmail.com wrote: > >> >> The Slowman fool puked: > >> >> ===================== > >> >> >> > >> >> > The point is that if the current is zero for one third of the time, > >> >> > positive for one third of the time and negative for one third of the time, > >> >> ** Not how real "mod sine" inverters operate. > >> >> There are two requirements on such devices: > >> >> > >> >> 1. Output the normal supply peak voltage. > >> >> > >> >> 2. Output the normal supply RMS voltage. > >> >> > >> >> Using these two, the "off" time must be 50%. > >> >> > >> >> Using only 33% would result in incandescent lamps failing in seconds. > >> > > >> >The standard modified sine wave has an off time of 33% and doesn't blow up incandescent lamps. > >> > >> At what DC input voltage ? The clamp time will depend on battery > >> voltage to regulate the output to the proper RMS voltage. > > > >Not in a modified sine wave converter. You typically use some other system to fix the output voltage. > > > >You can play with the off-time to regulate the output power, but as you move away from 33%, off time, the third harmonic content in the output goes up. > > I suppose you could design a Modified Square Wave inverter to do that > but at some point, it might just be as easy to just make a real > sinewave.It isn't.> The old 50Hz/60Hz MSW inverters changed the off/clamp time to regulate > the output voltage based on load and battery voltage. I worked on > them for years.The ones you worked on might have, but it's just one of the options.> Either way, the distortion is bad, around 30% THD but it is measured > slightly different for power waveforms that it is for audio power > amps. Similar though. For inverters, only the first 41 or so > harmonics matter in the THD specs.And the third harmonic matters a lot. Reducing it to zero helps quite a bit.> >This doesn't seem to worry Phil, but it does throw away one of the few good points of a pretty crude system.-- Bill Sloman, Sydney
Reply by ●August 9, 20212021-08-09
On Sun, 8 Aug 2021 21:04:49 -0700 (PDT), Anthony William Sloman <bill.sloman@ieee.org> wrote:>On Monday, August 9, 2021 at 1:50:37 PM UTC+10, boB wrote: >> On Sun, 8 Aug 2021 00:46:06 -0700 (PDT), Anthony William Sloman >> <bill....@ieee.org> wrote: >> >> >On Sunday, August 8, 2021 at 3:35:37 PM UTC+10, boB wrote: >> >> On Fri, 6 Aug 2021 22:25:41 -0700 (PDT), Anthony William Sloman >> >> <bill....@ieee.org> wrote: >> >> >> >> >On Saturday, August 7, 2021 at 1:56:14 PM UTC+10, palli...@gmail.com wrote: >> >> >> The Slowman fool puked: >> >> >> ===================== >> >> >> >> >> >> >> > The point is that if the current is zero for one third of the time, >> >> >> > positive for one third of the time and negative for one third of the time, >> >> >> ** Not how real "mod sine" inverters operate. >> >> >> There are two requirements on such devices: >> >> >> >> >> >> 1. Output the normal supply peak voltage. >> >> >> >> >> >> 2. Output the normal supply RMS voltage. >> >> >> >> >> >> Using these two, the "off" time must be 50%. >> >> >> >> >> >> Using only 33% would result in incandescent lamps failing in seconds. >> >> > >> >> >The standard modified sine wave has an off time of 33% and doesn't blow up incandescent lamps. >> >> >> >> At what DC input voltage ? The clamp time will depend on battery >> >> voltage to regulate the output to the proper RMS voltage. >> > >> >Not in a modified sine wave converter. You typically use some other system to fix the output voltage. >> > >> >You can play with the off-time to regulate the output power, but as you move away from 33%, off time, the third harmonic content in the output goes up. >> >> I suppose you could design a Modified Square Wave inverter to do that >> but at some point, it might just be as easy to just make a real >> sinewave. > >It isn't.If you have to regulate the secondary voltage just to keep the MSW at a specific duty cycle, then it isn't too far from making a sinewave in the first place. Most of the RE sinewave inverters these days for off-grid use just make sinewaves at 20+ kHz and boost by way of a 50/60 Hz transformer.> >> The old 50Hz/60Hz MSW inverters changed the off/clamp time to regulate >> the output voltage based on load and battery voltage. I worked on >> them for years. > >The ones you worked on might have, but it's just one of the options. > >> Either way, the distortion is bad, around 30% THD but it is measured >> slightly different for power waveforms that it is for audio power >> amps. Similar though. For inverters, only the first 41 or so >> harmonics matter in the THD specs. > >And the third harmonic matters a lot. Reducing it to zero helps quite a bit.Just reducing the third harmonic isn't enough for a LOT of things. Might help motors a lot though. The sharp edges are very bad on many things. Try one of those specific Duty Cycle MSW inverters on a triac light dimmer for instance. Or try getting the buzz of the MSW out of your MW radio receivers... Or a lot of times even out of a stereo running off of that waveform. Just make sinewaves. No exceuse these days except for the cheapest of the cheapest small inverters. I still use one in the car just to charge the cell phone or laptop which works OK. boB> >> >This doesn't seem to worry Phil, but it does throw away one of the few good points of a pretty crude system.
