Yes I have and that is manifestly not the problem. The problem seems to require both a 30 VDC Input and an 480 VAC Input on the same pair of pins. That implies a transformer and the transformer will in fact block the DC voltage. You're just changing the problem to fit your experience instead of listening to the TS/OP requirements. You might want to pick your knuckles up off the ground. It is time to put up or shut up.

Okay? let's look at this from the technical standpoint being I have no idea where you are coming from with the need for an iron core AC only transformer up front of the conversion system.

A typical line powered SMPS takes AC current rectifies it to DC then converts that to high-frequency AC then steps it up or down ad required then rectifies it to DC again.

Is there any reason DC can't be fed to the input rectifiers AC side thus making its input universally tolerable to any AC or DC input at any given time so long as the input voltage is within it's working range?

What if we just called it a 24 - 480 VAC to 24 VDC 10 amp SMPS based converter? Would that make any difference opposed to calling it a 30 - 700 VDC to 24 VDC 10 amp SMPS based converter??

Say I have a common universal voltage SMPS based power pack that runs on anything between 85 and 260 volts AC power. Is there any reason by your logic that I can't simply put DC power between 120 VDC and 370 VDC into it being it's already taking that AC input and rectifying it to DC at that voltage anyway?

Also, where did the OP say it had to be an iron core based transformer system? He referred to TDK Lamda power supply bricks which most of their models are SMPS based and not iron core transformer based linear units which I take to imply that SMPS based conversion is more than acceptable and pretty much necessary if a wide input voltage range of both DC and AC power is expected.

What more info do you need from me?

If you know how SMPS units work and how multi-tap iron core transformers work then it shouldn't be too much of a step to envision how a multi-tapped high-frequency transformer in a SMPS based system could be designed and implemented to cover a much wider than normal supply voltage range?

 

Okay? let's look at this from the technical standpoint being I have no idea where you are coming from with the need for an iron core AC only transformer up front of the conversion system.

Well, they *must* have a transformer in it, or this discussion violates TOS.

 

Well, they *must* have a transformer in it, or this discussion violates TOS.

What do you think the high-frequency transformer in a SMPS is for and by SMPS I am not referring a simple single winding buck/boost unit?

Just because it's not a laminated iron core 50-60 Hz unit does not make it a violation of the TOS here.

 

What do you think the high-frequency transformer in a SMPS is for and by SMPS I am not referring a simple single winding buck/boost unit?

Just because it's not a laminated iron core 50-60 Hz unit does not make it a violation of the TOS here.

That'll be one for the mods to answer, since it is above my pay grade. Certainly a part of the circuit is not isolated from the 480VAC mains. I think it violates the TOS, but obviously your mileage is different. So you're saying the input can be from 30VDC to 680VDC past the rectifier and first filter capacitor. That filter capacitor certainly sounds like it might have a hazardous and or lethal voltage on it.

Is the high frequency transformer a step up or step down? What is the range of AC out voltage that you convert back to DC before creating the 24V DC output?

 

That'll be one for the mods to answer, since it is above my pay grade. Certainly a part of the circuit is not isolated from the 480VAC mains. I think it violates the TOS, but obviously your mileage is different. So you're saying the input can be from 30VDC to 680VDC past the rectifier and first filter capacitor. That filter capacitor certainly sounds like it might have a hazardous and or lethal voltage on it.

Possibly yes but so far modifying computer power supplies and other SMPS based devices has never been a red flag topic. Same with fixing or building higher voltage AC and DC power supplies either.

Direct line powered capacitive coupled power supplies seem to be then red flag issue and most everytng else flys just fine regardless of its intermediate working voltage or process of conversion or anything else just so long as it uses induction based voltage conversion and or isolation from input to output on an assumed to be common grid based power source.

So far nothing was said about the supposed 30 VDC to 480 VAC source being line powered so...... I don't know really.

 

Say I have a common universal voltage SMPS based power pack that runs on anything between 85 and 260 volts AC power. Is there any reason by your logic that I can't simply put DC power between 120 VDC and 370 VDC into it being it's already taking that AC input and rectifying it to DC at that voltage anyway?

Seems reasonable to me, with the caveat that two of the diodes in the usual bridge rectifier would be carrying the total load current continuously with the DC input, rather than having a half-cycle respite each cycle with an AC input, so the bridge would need to be rated accordingly.

 

Seems reasonable to me, with the caveat that two of the diodes in the usual bridge rectifier would be carrying the total load current continuously with the DC input, rather than having a half-cycle respite each cycle with an AC input, so the bridge would need to be rated accordingly.

I don't think I have ever seen a properly built power supply regardless of size that didn't use input stage rectifiers that weren't rated for considerably more than the power supply maximum current requirements.

I know I have pulled a lot of 6 - 10 amp rate bridge rectifiers out of od 300 - 500 watt computer power supplies that had less than half those ratings for maximum input current requirements.

Same with high powered inverter welders and plasma cutter power supplies as well. 80 - 100+ amp bridge units on machines that had at best 40 -50 amp single phase input current ratings.

 

I think this is possible.
You take a controller with over voltage protection of ~50V that will operate a flyback of 30V to XV and in another winding you put a controler with under voltage protection of ~200V.

That way only one of them will work

 

If I understand correctly then what you want that the schematic block diagram maybe like as below.

 

I don't think I have ever seen a properly built power supply regardless of size that didn't use input stage rectifiers that weren't rated for considerably more than the power supply maximum current requirements.

Unfortunately, too many power supplies being sold aren't properly built.

 

Unfortunately, too many power supplies being sold aren't properly built.

Not MY design and fabrication problem.

 

The hijacking posted was moved to --
The problem of input 85VAC-265VAC/50Hz or 18VDC-36VDC, Output 15W.

 

If I understand correctly then what you want that the schematic block diagram maybe like as below.

View attachment 109740

The TS said in one of his original posts that two separate inputs was NOT what he wanted. He wants one(1) pair of input terminals that will accept either 30 VDC OR 480 VAC. @tcmtech has hinted at a possible solution but refuses to answer my legitimate questions about the design of a high frequency transformer that would follow a bridge rectifier on the input. For the third time put up or shut up.

 

@tcmtech has hinted at a possible solution but refuses to answer my legitimate questions about the design of a high frequency transformer that would follow a bridge rectifier on the input. For the third time put up or shut up.

Seriously? WTF?

READ UP ON HOW SWITCH MODE POWER SUPPLIES ARE BUILT. I'VE SAID IT MULTIPLE TIMES NOW AND EVEN DESCRIBED IT IN REASONABLE DETAIL IN POST 21.

WHAT MORE DO YOU NEED FROM ME?

 

The TS said in one of his original posts that two separate inputs was NOT what he wanted. He wants one(1) pair of input terminals that will accept either 30 VDC OR 480 VAC. @tcmtech has hinted at a possible solution but refuses to answer my legitimate questions about the design of a high frequency transformer that would follow a bridge rectifier on the input. For the third time put up or shut up.

I knew that the TS could be considering the two inputs combine to one, but because I didn't decide the input part which way is better to detect the AC and DC and auto switching to the input circuits, so I still uploaded the block diagram designed for the posted #1, maybe you and some other helper may find some weak point in the block diagram.

 

I knew that the TS could be considering the two inputs combine to one, but because I didn't decide the input part which way is better to detect the AC and DC and auto switching to the input circuit, so I still uploaded the block diagram designed for the posted #1, maybe you and some other helper may find some weak point in the block diagram.

I think your block diagram is just fine and PB is either trolling us or has zero real understanding of what a real Switch Mode Power Supply is and how they work. If he did I doubt he would be asking his repeated questions about how to step DC voltage down with a high-frequency transformer.

Personally, to me, the generalized term SMPS should be as familiar and understandable to any electronics hobbyist and how they can be used as to what the terms bridge rectifier or electrolytic capacitor is.

Still not sure how that makes me the "Knuckle dragger' for understanding the basic concepts though.

 

So anyway PB's trolling aside....

I think that if I was to design such a power supply I would go with a basic but fairly adaptable flyback driver IC like the TEA1751, http://www.mouser.com/search/Refine.aspx?Keyword=123046505&FS=True&Ntk=P_MarCom&Tb=datasheets , series being it has a low parts count but can work well in an application where high supply voltage ripple on top of a wide input voltage range are encountered.

The only major overall circuit design variation would be to modify the flyback transformers primary to have three taps and the pin 13 switching device driver output would be sent to a triple AND gate that selects between one of three switching devices drivers that are attached to the three primary coil taps.

For the logic that determines which of the three switching devices is selected that could be done with simple op amp comparator logic that monitors the primary side DC rail voltage and thus selects which AND gate and its related switching device are active.

As for the switching devices themselves since each one would be subjected to the same HV DC rail voltages when a 480 VAC input was being used I would go with a minimum 1200 volt rated power MOSFET or high-speed IGBT such as the IKW08T120FKSA1,
, http://www.digikey.com/product-search/en/discrete-semiconductor-products/transistors-igbts-single/1376382?k=&pkeyword=&pv814=15&FV=cb00072,fff40015,fff8007e&mnonly=0&newproducts=0&ColumnSort=0&page=1&stock=1&quantity=0&ptm=0&fid=0&pageSize=25 , or similar rated device of either MOSFET or IGBT design.

However when running at the lowest input of 30 VDC it's possible that the switching device on the lowest voltage tap may have to deal with current peaks around 20 - 25 amps so that one would need to either have two of the lower current devices like the two upper tap points use running parallel to each other or have one device with a higher current capacity rating than the upper two devices.

One other caveat with the multiple switching devices and multi-tapped flyback transformer design is that when either one of the two lower voltage devices are in operation the device or devices above it would b subjected to higher voltage feedback (autotransformer effect) so it would be necessary to have HV blocking diodes (something like this or similar, http://www.digikey.com/product-search/en/discrete-semiconductor-products/diodes-rectifiers-single/1376383?k=&pkeyword=&pv96=24&pv916=5&FV=fff40015,fff8007f&mnonly=0&newproducts=0&ColumnSort=0&page=1&quantity=0&ptm=0&fid=0&pageSize=25 ) between them and the transformer so they can't feedback to the DC rail essentially creating a short circuit when a lower voltage device and related tap are active.

Still all said and done I thnk a 240 watt capable 24 volt DC output power supply that could handle any input voltage from 24 VAC to 530 VAC (480 VAC + 10%) / 30VDC to 750 VDC (AKA 30 VDC - 480 VAC for the wee simple folk ) input could be made using any common SMPS driver IC and some extra logic control to utilize multiple switching devices and primary taps on an otherwise standard flyback transformer based SMPS design.

 

The hijacking posted was moved to --
The problem of input 85VAC-265VAC/50Hz or 18VDC-36VDC, Output 15W.

I had the similar requirement
i was unable to implement now i hope it can be done.........!!!

 

I suppose the test of who is trolling and who is blowing smoke will come from the TS/OP. If he got what he wanted then it is all good. If after 38 posts he doesn't have squat, then we will have our answer.

 

I suppose the test of who is trolling and who is blowing smoke will come from the TS/OP. If he got what he wanted then it is all good. If after 38 posts he doesn't have squat, then we will have our answer.

Perhaps but so far I have seen zero info from you relating to how to make such a power supply and I have gotten several likes for my posts relating to theories on how to make one VS you getting none for any posts so hows that tally up on smoke blowing VS supplying viable info?

BTW Alley Cat asked for ideas on how to build a power supply that works with a
30VDC to 480VAC Input range on one input
not for one at both 30 VDC and 480 VAC at the same time on the same input.