13.8v (or 15V), 8A switching power supply - Electronic Circuits Projects Diagrams Free

BengBear · 10th May 2008, 01:46 PM

Hi,
I wish to build a switching power supply, input - 230Vac, 50Hz, output - 13.8Vdc (or 15V) and 8 Amp, instead of the conventional linear power supply.

I am a new member and new to switching power supply.

Appreciate an applicable and 'simple' circuit for such type of power supply from any kind soul.

Regards

mvs sarma · 10th May 2008, 02:26 PM

www.powerint.com has simple and good devices like TINY and LNK series, please see the site and they have lot of application notes.
there are many others like ST Micro's viper50,

petrv · 11th May 2008, 12:16 PM

I think for such power you'd rather need the TOPSwitch family, TINY family is for much smaller power supplies.
But if you are new to switching power supplies I don't think this is a good project for a start, complicated and can be even dangerous. Better to start e.g. with a buck controller - look at National Semiconductor, ON Semiconductor ....

Petr

BengBear · 18th May 2008, 01:43 PM

Hi,
After reviewing viper, power int., it seems getting special type of transformer is rather inconvenient. ST L4970A may be a good option to convert 230Vac (rectifying 28Vdc), 50hz to (0 to 25Vdc and 10A). And this is fed into pin 9, Vin. The question is what current input.

Referring to some design options, it appears the input should be

V0 times I0 div by Vin (V0 and I0 are output voltage and current) which is
25x10/40 =6.25, convert this to rms current 6.25/1.414 = 4.42 Amp ac.
Hence transformer VA is 28 x 4.42 about 124VA.

As this is the first time I am using this type of switching regulator, welcome any one who has this experience to review and comment.

mvs sarma · 18th May 2008, 02:16 PM

Quote:

Originally Posted by BengBear

Hi,
After reviewing viper, power int., it seems getting special type of transformer is rather inconvenient. ST L4970A may be a good option to convert 230Vac (rectifying 28Vdc), 50hz to (0 to 25Vdc and 10A). And this is fed into pin 9, Vin. The question is what current input.

Referring to some design options, it appears the input should be

V0 times I0 div by Vin (V0 and I0 are output voltage and current) which is
25x10/40 =6.25, convert this to rms current 6.25/1.414 = 4.42 Amp ac.
Hence transformer VA is 28 x 4.42 about 124VA.

As this is the first time I am using this type of switching regulator, welcome any one who has this experience to review and comment.

Do you mean to use a transformer at 230V to 20V and rectify and then use a non-isolated SMPS using L4970?
Even then you might need an inductor of good current carrying capacity, I believe. The transformer would again be bulky at the 50Hz point.

BengBear · 18th May 2008, 06:17 PM

Hi Sarma,
Went into power int (PI), design the circuit and forwarded to PI but they could not support transformer and inductor locally (Singapore), based on the design needs.

Search around and found L4970A a switching regulator. Attached is the design using L4970A and expanded my required output voltage and current supply from 7A to 10A.

Agree, base on this design the transformer needed would be bulky again, not so much as before using conventional transformer and rectifier without switching regulator.

If somebody in Singapore can supply those PI transformer and inductor, it would be most welcome.

mvs sarma · 18th May 2008, 07:26 PM

Quote:

Originally Posted by BengBear

Hi Sarma,
Went into power int (PI), design the circuit and forwarded to PI but they could not support transformer and inductor locally (Singapore), based on the design needs.

Search around and found L4970A a switching regulator. Attached is the design using L4970A and expanded my required output voltage and current supply from 7A to 10A.

Agree, base on this design the transformer needed would be bulky again, not so much as before using conventional transformer and rectifier without switching regulator.

If somebody in Singapore can supply those PI transformer and inductor, it would be most welcome.

do you want 0 to 25 V variable supply?
If so please see the other site where audioguru has moderated a circuit to give upto 5 amps.

Ubergeek63 · 18th May 2008, 08:45 PM

there are a number of companies now that supply some of those transformers.

Of course the daring could roll their own. I do tend to prefer planars myself, but it is not easy to cut good windings and most do not have access to thin PCB core for the primary windings. One thing to watch out for is the reflected voltage: you will have upto about 400V on the supply plus the output multiplied by the turns ratio to the FET.

BengBear · 18th May 2008, 11:26 PM

Hi Ubergeek63,
Mind giving me details of these companies providing those transformer as detail in attachment. Hope some soul or companies in Singapore who are willing to sell them.

Ubergeek63 · 19th May 2008, 01:28 AM

Planar transformers Planar magnetics Planar Technology

http://www.coilcraft.com/pdfs/pl140.pdf

You generally will not find them in apps for AC line apps because most off the shelf units do not pass the safety isolation requirements. (5KV isolation is not easily to get in such a small package. While I have done it, there is not space for high isolation and high current)

BengBear · 23rd May 2008, 01:08 PM

Hi Ubergeek63,
Visited ww2.pulseeng.com, Pulse Technitrol Company, and contacted its local administrator. All supports are out of town.

I am looking for a suitable Planar transformer and workable regulator and circuit to convert 230Vac to anything equal or more than 18Vdc, 10Amp.
Appreciate any recommendation.

Ubergeek63 · 23rd May 2008, 05:00 PM

you will never be able to walk into a store and get a 200W switching transformer or a 300VA (what you would need for 50-60Hz) transformer.

I can design the things, but they still have to be built. You either need to order from a company who makes them, where ever they may be, or order a 50Hz unit from someone who has them and pay the shipping.

mvs sarma · 24th May 2008, 10:51 AM

Quote:

Originally Posted by BengBear

Hi Ubergeek63,
Visited ww2.pulseeng.com, Pulse Technitrol Company, and contacted its local administrator. All supports are out of town.

I am looking for a suitable Planar transformer and workable regulator and circuit to convert 230Vac to anything equal or more than 18Vdc, 10Amp.
Appreciate any recommendation.

I wonder, whether you really need a 8 amps rated charger at 13.8V?

What capacity batteries you wanted to us the charger for?

BengBear · 24th May 2008, 12:27 PM

It is for powering something else, not for charging.

There are standard off the shelf 250Watt Planar transformer, but I need a matching regulator and associated circuit, as Planar is new to me. Reason for going for planar is that it is compact and much lighter than a traditional transformer, rectifier and etc. As for pure switching power supply, special wound transformer is needed.

mvs sarma · 24th May 2008, 12:48 PM

Quote:

Originally Posted by BengBear

It is for powering something else, not for charging.

There are standard off the shelf 250Watt Planar transformer, but I need a matching regulator and associated circuit, as Planar is new to me. Reason for going for planar is that it is compact and much lighter than a traditional transformer, rectifier and etc. As for pure switching power supply, special wound transformer is needed.

Perhaps your concept is right, if you source the L4970A, perhaps you can complete it. You may have to use a high power bridge rated 20 amps to safely deliver 8 amps.

Please see this pdf
http://www.rason.org/Projects/powsupply/powsupply.pdf

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10th May 2008, 01:46 PM	(permalink)
BengBear	13.8v (or 15V), 8A switching power supply Hi, I wish to build a switching power supply, input - 230Vac, 50Hz, output - 13.8Vdc (or 15V) and 8 Amp, instead of the conventional linear power supply. I am a new member and new to switching power supply. Appreciate an applicable and 'simple' circuit for such type of power supply from any kind soul. Regards

10th May 2008, 02:26 PM	(permalink)
mvs sarma	www.powerint.com has simple and good devices like TINY and LNK series, please see the site and they have lot of application notes. there are many others like ST Micro's viper50, __________________ Regards, Sarma.

11th May 2008, 12:16 PM	(permalink)
petrv	I think for such power you'd rather need the TOPSwitch family, TINY family is for much smaller power supplies. But if you are new to switching power supplies I don't think this is a good project for a start, complicated and can be even dangerous. Better to start e.g. with a buck controller - look at National Semiconductor, ON Semiconductor .... Petr

18th May 2008, 01:43 PM	(permalink)
BengBear	13.8v (or 15V), 8A switching power supply Hi, After reviewing viper, power int., it seems getting special type of transformer is rather inconvenient. ST L4970A may be a good option to convert 230Vac (rectifying 28Vdc), 50hz to (0 to 25Vdc and 10A). And this is fed into pin 9, Vin. The question is what current input. Referring to some design options, it appears the input should be V0 times I0 div by Vin (V0 and I0 are output voltage and current) which is 25x10/40 =6.25, convert this to rms current 6.25/1.414 = 4.42 Amp ac. Hence transformer VA is 28 x 4.42 about 124VA. As this is the first time I am using this type of switching regulator, welcome any one who has this experience to review and comment.

18th May 2008, 08:45 PM	(permalink)
Ubergeek63	there are a number of companies now that supply some of those transformers. Of course the daring could roll their own. I do tend to prefer planars myself, but it is not easy to cut good windings and most do not have access to thin PCB core for the primary windings. One thing to watch out for is the reflected voltage: you will have upto about 400V on the supply plus the output multiplied by the turns ratio to the FET.

19th May 2008, 01:28 AM	(permalink)
Ubergeek63	Planar transformers Planar magnetics Planar Technology http://www.coilcraft.com/pdfs/pl140.pdf You generally will not find them in apps for AC line apps because most off the shelf units do not pass the safety isolation requirements. (5KV isolation is not easily to get in such a small package. While I have done it, there is not space for high isolation and high current)

23rd May 2008, 01:08 PM	(permalink)
BengBear	Hi Ubergeek63, Visited ww2.pulseeng.com, Pulse Technitrol Company, and contacted its local administrator. All supports are out of town. I am looking for a suitable Planar transformer and workable regulator and circuit to convert 230Vac to anything equal or more than 18Vdc, 10Amp. Appreciate any recommendation.

23rd May 2008, 05:00 PM	(permalink)
Ubergeek63	you will never be able to walk into a store and get a 200W switching transformer or a 300VA (what you would need for 50-60Hz) transformer. I can design the things, but they still have to be built. You either need to order from a company who makes them, where ever they may be, or order a 50Hz unit from someone who has them and pay the shipping. Last edited by Ubergeek63; 23rd May 2008 at 05:03 PM.

24th May 2008, 12:27 PM	(permalink)
BengBear	It is for powering something else, not for charging. There are standard off the shelf 250Watt Planar transformer, but I need a matching regulator and associated circuit, as Planar is new to me. Reason for going for planar is that it is compact and much lighter than a traditional transformer, rectifier and etc. As for pure switching power supply, special wound transformer is needed.