Power supply advice needed

Hi to all. I am going to be designing a psu for one of our products. It's going to be 220Vac in 13V dc (~15 - 20W) out.Must be isolated.Reasonable regulation. It will charge a battery (13.8V) and power a logic board(with its own post regulator) Cost is a big issue here. Smaller the better obviously. I am leaning towards using one of the Topswitch line of switching regs for the job. Quick look shows TOP244 as probably being suitable. Does anyone have any better / cheaper suggestions for tackling this job. Cheers Rob

FWIW, I would make a selection of one of the countless Chinese vendors of switched-made power wallplug adaptors. It also circumvents CE / UL etc issues in a convenient way - and pricewise you cannot beat it. The power requirement you quote is very common.

On Thu, 28 Sep 2006 12:32:27 +0200, Ren? Gave us:

HiTek Power has plenty of wall mount (or mid cord) DC supplies that can do that wattage. They also supply supplies as OEM equipment to many companies. Likely quite cheap, once you get into buying some numbers from them. One or two may be a bit more expensive. Be sure to get quotes at different purchase size levels to get an understanding of your cost of incorporating it into your design. Also, a wall mounted supply saves you the cost of an entry module as well as the cord. All you need now is to choose a DC pin style connector (or not there are hard wired designs too).

Hi there. This is going to be incorporated into the product,.ie on the same pcb.

OK - I understand. This is what we usually try to avoid at all costs - it is IMHO *much* more convenient/ cheap/ timesaving to get the mains related stuff external. But probably you have good reasons not to do that.

I've used the Topswitch devices before. Easy to use and they seem pretty reliable. Don't expect maximum efficiency though.

Look for MeanWell power supplies. Good and cheap. Even in single qty these bricks are already below $10.

Meindert

I've used some TOPSwitch'es by PI and they work very well, but you can also give a try at cheaper alternatives, like some Panasonic MIP ICs (MIP0221SY, MIP160...) . I have not used them, though. They seem to have plagiarized the TOPSwitch products. Datasheets are poor.

Best,

Are you prepared to go through all of the necessarily approvals for bringing the mains power into your unit. This is why others have suggested that you get already approved wall plug unit. You will save a lot of money.

Regards,

Boris Mohar

Got Knock? - see: Viatrack Printed Circuit Designs (among other things)

void _-void-_ in the obvious place

An external PSU still requires on-board regulation if you like to design stuff that keeps working.

On Thu, 28 Sep 2006 15:58:26 +0200, Ren? Gave us:

One could *still* use a dongle and incorporate it into the case of the product.

On Fri, 29 Sep 2006 16:13:41 GMT, snipped-for-privacy@puntnl.niks (Nico Coesel) Gave us:

On board current limiting would perform just fine as the only safety needed. Unless one chooses some lame fire hazard vendor for the dongle.

On Fri, 29 Sep 2006 09:14:50 -0400, Boris Mohar Gave us:

That is actually the biggest and best reason to feed your device with a DC feed.

On Fri, 29 Sep 2006 07:52:25 +0200, "Meindert Sprang" Gave us:

For 30 Watts? Remember: One gets what one pays for.

"JoeBloe" schreef in bericht news: snipped-for-privacy@4ax.com...

Quite often, a device needs direct mains power as well as some DC.

I don't think so. External PSUs are usually utter crap so you'll need at least some filtering (EMC), overvoltage / reverse polarity protection and short circuit protection. All of these may cause a considerable drop in the supplied voltage.

Indeed. I recently got a 3000 $US TFT panel (with some FPGA based image processing) which didn't work. It turned out the external crappy PSU put 20V on its 5V output. Ofcourse no protection so all logic including the FPGAs got fried.

No - one gets what one's bean counters are willing to pay for.

RL

On Sat, 30 Sep 2006 01:20:44 +0200, "Frank Bemelman" Gave us:

You're not making any sense. Most electrical circuits that are using electronic components need DC to do that. What devices, transducers, etc. would need mains power to operate short of an AC run motor, etc.? Unless the device is being used to switch AC feeds as in a relay device, it won't need an AC feed.

I cannot think of many "devices" that require it. Even my PC could be fed by an external "dongle" type supply. So could my stereo if it came right down to it. All there would need to be is someone designing such a multi-tap external supply for the job. Absolutely nothing to keep it from working though.

If the device takes the AC feed and then makes the DC power it needs "on board", then it could have been designed to accept that DC from external sources.