Trying to identify SMD with label scrubbed off - PWM, inverter, 100W 12VDC to 120VAC modified sine wave

On Saturday, August 7, 2021 at 4:31:41 PM UTC+10, John Robertson wrote:
> On 2021/08/06 8:28 p.m., Anthony William Sloman wrote: 
> > On Saturday, August 7, 2021 at 8:05:40 AM UTC+10, John Robertson wrote: 
> >> On 2021/08/06 1:56 p.m., legg wrote: 
> >>> On Fri, 6 Aug 2021 12:19:47 -0700, John Robertson <sp...@flippers.com>  wrote:
> >>>> On 2021/08/05 9:25 p.m., legg wrote: 
> >>>>> On Thu, 5 Aug 2021 18:05:45 -0700, John Robertson <sp...@flippers.com> wrote: 
 
<snip> 

> > It's well known. You can do better - Don Lancaster's magic sine waves - but it gets messy. 
> >
> Yes, I'm sure I could do better, but this may be very low volume so I 
> figured just modify an existing design. The idea here is to modify the 
> frequency to change the speed of a synchronous motor perhaps 10 to 15% 
> at most. 

It's not a great waveform for driving a synchronous motor, but better than a square wave.
 
> I see Don Lancaster's name all over the place. Have his TTL and CMOS  Cookbooks - a great help when I was starting out - clever guy who writes clearly. 

Not all that clever, but he does write very clearly, and doesn't waste his time explaining stuff that is difficult to explain. I first came across him when he started writing for 
Byte, to which my wife had given me a foundation subscription, and which I kept on reading until it folded. Nothing I read of his ever told me anything I didn't already know, but he did put it neatly.

> If the device proves popular then I will design something appropriate  and make a cute box, etc. 

Ten to fifteen percent you could get out of a Baxandall inverter by switching capacitors in and out of the resonant circuit, but that would only be worth doing if you didn't need much power.

-- 
Bill Sloman, Sydney

On Saturday, August 7, 2021 at 4:54:10 PM UTC+10, palli...@gmail.com wrote:
> The Slowman fuckwit 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. 
> > 
> > A regular 240V rms sine wave has a peak voltage of 377V.
> ** ROTFLMAO !!!!!!!!!!!!!!!!!
> > A modified sine wave would produce 240V rms if the "on" voltages were +/-294 volts.
> ** Absurd & insane crap.
> > 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.
> ** Same INSANE error.
> > I don't know what kind of half-wits you have been dealing with,
> ** I'm dealing with a FUCKING MASSIVE one right now !! 
> 
> FYI : you raving NUT CASE 

Probably. I was using pi/2  which - on reflection  - would have been right for the average voltage rather than the average power. I'll have to dust off my integral calculus and do it right.
 
> 240V rms sine = 340 V peak 
> 
> 340 V continuous = double power with a resistive load. 
> 
> 340 V at 50% duty cycle = same as 240 V rms sine 

So what's voltage you need to get the same a 240V sine wave at a 66.6% duty cycle? Perhaps 294V?

And why wouldn't you use that?

-- 
Bil Sloman, Sydney

 The Slowman fuckwit 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. 
> > > 
> > > A regular 240V rms sine wave has a peak voltage of 377V. 
> > ** ROTFLMAO !!!!!!!!!!!!!!!!! 
> > > A modified sine wave would produce 240V rms if the "on" voltages were +/-294 volts. 
> > ** Absurd & insane crap. 
> > > 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. 
> > ** Same INSANE error. 
> > > I don't know what kind of half-wits you have been dealing with, 
> > ** I'm dealing with a FUCKING MASSIVE one right now !! 
> > 
> > FYI : you raving NUT CASE
==========================

> Probably. I was using pi/2 which - on reflection - would have been right for 
> the average voltage rather than the average power. I'll have to dust off my integral calculus and do it right.
> > 240V rms sine = 340 V peak 
> > 
> > 340 V continuous = double power with a resistive load. 
> > 
> > 340 V at 50% duty cycle = same as 240 V rms sine
> So what's voltage you need to get the same a 240V sine wave at a 66.6% duty cycle? Perhaps 294V? 
> 
> And why wouldn't you use that? 

**  See rule 1. 

The reason is bloody obvious. 


 

On Saturday, August 7, 2021 at 5:21:39 PM UTC+10, palli...@gmail.com wrote:
> The Slowman fuckwit 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. 
> > > > 
> > > > A regular 240V rms sine wave has a peak voltage of 377V. 
> > > ** ROTFLMAO !!!!!!!!!!!!!!!!! 
> > > > A modified sine wave would produce 240V rms if the "on" voltages were +/-294 volts. 
> > > ** Absurd & insane crap. 
> > > > 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. 
> > > ** Same INSANE error. 
> > > > I don't know what kind of half-wits you have been dealing with, 
> > > ** I'm dealing with a FUCKING MASSIVE one right now !! 
> > > 
> > > FYI : you raving NUT CASE
> ==========================
> > Probably. I was using pi/2 which - on reflection - would have been right for 
> > the average voltage rather than the average power. I'll have to dust off my integral calculus and do it right. 

Actually it is trigonometry.

Cos 2.theta = 1 - 2.(sin theta) ^2.

which means that (sin theta)^2 =  0.5 - cos 2.theta

So the integral of ( V. (sin theta))^2 over theta from 0 to 90 degrees is [0.5 +  sin 2.theta] or V^2/root 2.

So the peak voltage is 339.41V for a 240V sine wave.

> > > 240V rms sine = 340 V peak 
> > > 
> > > 340 V continuous = double power with a resistive load. 
> > > 
> > > 340 V at 50% duty cycle = same as 240 V rms sine 
> > So what's voltage you need to get the same a 240V sine wave at a 66.6% duty cycle? Perhaps 294V? 
> > 
> > And why wouldn't you use that?
> ** See rule 1. 

A rule you seem to have invented. Regular modified sine wave generators don't seem to take it too seriously.
 
> The reason is bloody obvious.

The justification for making that choice might be obvious, but having third harmonic content  in the output isn't an advantage, and people who know what they are doing are free to make a different choice.

-- 
Bill Sloman, Sydney

 The Slowman fuckwit PUKED : 

==========================

> > ** See rule 1.
> A rule you seem to have invented. 
>
>Regular modified sine wave generators don't seem to take it too seriously.
>

**  Absolute certainty a fucking, know nothing TROLL like YOU  has never even seen a REAL one. 

 



....  Phil 

On Fri, 6 Aug 2021 15:05:28 -0700, John Robertson <spam@flippers.com>
wrote:

>
>On 2021/08/06 1:56 p.m., legg wrote:
>> On Fri, 6 Aug 2021 12:19:47 -0700, John Robertson <spam@flippers.com>
>> wrote:
>> 
>>>
>>> On 2021/08/05 9:25 p.m., legg 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...
<snip>
>> 
>As I said I'd much rather take something already built and modify it for 
>small runs, rather than have to design and build - which may be more 
>fun, but isn't cost effective.
>
>John :-#)#

Is there a relationship between the RC oscillator waveforms and 
the low frequency output drive?

Does a 10% shift in the R or C get a corresponding shift in the 
~60Hz cycle?

Is the input DC/DC synchronized from the same clock?

RL

On Saturday, August 7, 2021 at 6:51:28 PM UTC+10, palli...@gmail.com wrote:
> The Slowman fuckwit PUKED : 
> 
> ==========================
> > > ** See rule 1. 
> > A rule you seem to have invented. 
> > 
> >Regular modified sine wave generators don't seem to take it too seriously. 
> >
> ** Absolute certainty a fucking, know nothing TROLL like YOU has never even seen a REAL one. 

I might have. The kind of complicated high-end gear I worked on didn't go in for them, but my wife has colleagues who have consumer level gadgets to adapt their domestic gear to work on UK, US or Japanese main voltages when their owners are working overseas.

The 120V coffee grinder my wife bought in Boston used one for years when we lived in England and the Netherlands. We eventually gave it to somebody who was moving to a 120V country, and I bought a 240V replacement for us to use.

The theory is obvious enough - even if you don't know much about it - and it has been discussed here from time to  time.

-- 
Bill Sloman, Sydney

On 2021/08/07 3:43 a.m., legg wrote:
> On Fri, 6 Aug 2021 15:05:28 -0700, John Robertson <spam@flippers.com>
> wrote:
> 
>>
>> On 2021/08/06 1:56 p.m., legg wrote:
>>> On Fri, 6 Aug 2021 12:19:47 -0700, John Robertson <spam@flippers.com>
>>> wrote:
>>>
>>>>
>>>> On 2021/08/05 9:25 p.m., legg 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...
> <snip>
>>>
>> As I said I'd much rather take something already built and modify it for
>> small runs, rather than have to design and build - which may be more
>> fun, but isn't cost effective.
>>
>> John :-#)#
> 
> Is there a relationship between the RC oscillator waveforms and
> the low frequency output drive?
> 
> Does a 10% shift in the R or C get a corresponding shift in the
> ~60Hz cycle?
> 
> Is the input DC/DC synchronized from the same clock?
> 
> RL
> 

That was the direction I was planning on going as it looked the easiest 
way to modify the frequency. I've done this before on other inverters 
that didn't scrub the numbers off.

Application Notes are so very handy for this sort of thing - knowing the 
capabilities of the IC would be of some use to know how to get the range 
of output frequency I'm after. I guess I'll just plug with a resistor in 
the PWM clock - use some high value pot to tweak the value and watch the 
output on the scope or use my frequency counter once I have something 
that changes the Hz...

John :-#)#

On Sat, 7 Aug 2021 11:26:28 -0700, John Robertson <spam@flippers.com>
wrote:

>
>On 2021/08/07 3:43 a.m., legg wrote:
>> On Fri, 6 Aug 2021 15:05:28 -0700, John Robertson <spam@flippers.com>
>> wrote:
>> 
>>>
>>> On 2021/08/06 1:56 p.m., legg wrote:
>>>> On Fri, 6 Aug 2021 12:19:47 -0700, John Robertson <spam@flippers.com>
>>>> wrote:
>>>>
>>>>>
>>>>> On 2021/08/05 9:25 p.m., legg 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...
>> <snip>
>>>>
>>> As I said I'd much rather take something already built and modify it for
>>> small runs, rather than have to design and build - which may be more
>>> fun, but isn't cost effective.
>>>
>>> John :-#)#
>> 
>> Is there a relationship between the RC oscillator waveforms and
>> the low frequency output drive?
>> 
>> Does a 10% shift in the R or C get a corresponding shift in the
>> ~60Hz cycle?
>> 
>> Is the input DC/DC synchronized from the same clock?
>> 
>> RL
>> 
>
>That was the direction I was planning on going as it looked the easiest 
>way to modify the frequency. I've done this before on other inverters 
>that didn't scrub the numbers off.
>
>Application Notes are so very handy for this sort of thing - knowing the 
>capabilities of the IC would be of some use to know how to get the range 
>of output frequency I'm after. I guess I'll just plug with a resistor in 
>the PWM clock - use some high value pot to tweak the value and watch the 
>output on the scope or use my frequency counter once I have something 
>that changes the Hz...
>
>John :-#)#

Even if the input DC-DC is synced, going up in frequency by a factor
of 4 won't kill anything, but the load reg will suffer due to 
leakage inductance. Series gate resistors will get hotter and any
clamps will be stressed. Thermal imaging might pick out anything 
troublesome.

The output bridge doesn't care.

Loads might be more picky.

RL

On Fri, 6 Aug 2021 23:54:07 -0700 (PDT), Phil Allison
<pallison49@gmail.com> wrote:
<snip> 
>
>240V rms  sine  = 340 V peak
>
>340 V continuous  =   double power with a resistive load.
>
>340 V at 50% duty cycle  =  same as 240 V rms sine 
>
>Fucking Chemistry Freak. 
>
>
>
>.....  Phil 
>
The peak output voltage on this thing is 120v, in an 
attempt to power 120v AC loads, so a straight square 
wave ends up supplying 120v average, rms or whatever 
else you might want to call it.

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.

RL