Digital power factor correction

[PCBONEZ]

Re: Digital power factor correction

Politicians rule the world. The only thing I am expecting is for these politicians to legislate that the US will also go green and make a law requiring all new power supplies to have APFC. They will tell us that it makes power supplies more efficient, and show us the same ole bogus charts. Surely our politicians (the best paid politicians in the world) wouldn't lie to us?????

In order for Politicians to lie they would have to know what they are talking about.
I don't see that happening anytime soon.
.

[ratdude747]

Re: Digital power factor correction

hence why i would like to go into politics someday... since there are so many bum politicains out there, i think i could do better and i hope other would think so too. not that anybody here would vote for me... most around here seem to be extremely conservative while i tend to be liberal on a lot of things (not all).

as for apfc... i think there will be bigger things go through before they get to that. like car emissions and wind power.

[PCBONEZ]

Re: Digital power factor correction

Wind [and solar] power isn't going to do sh*t as an industry because without gov't subsidies it isn't 'efficient' at making money for investors.
The gov't is broke. - Subsidies are going away.

Obama's solution to make wind power 'efficient' at making money for investors is to tax the snot out of oil to make it more expensive than wind power alternatives.
- That's the gist of his "incentive plan" for wind and solar power.

That plan will actually work if he can get it through congress but gas and electricity prices will double or more in the process.

.

.

[Per Hansson]

Re: Digital power factor correction

PCBONEZ; that is interesting
I'll take Denmark as an example, one of our neigthbours here in Scandinavia
They produce 18% of their own electricity though wind power, that is an amazingly high number (highest in the world actually)
And they are very very proud of it

Untill someone like me comes up and asks where the other 82% comes from; the answer is coal plants in Germany!

Atleast this new uber PFC might allow them to use smaller gauge cabling to Germany
Haha, just kidding with you

[Toasty]

Re: Digital power factor correction

Back to the original post.

DigiKey, Mouser, Avnet have them. Avnet's cheapest.

Datasheets attached.

Cheers!
Toast

[Th3_uN1Qu3]

Re: Digital power factor correction

You can do an universal-input PSU WITHOUT needing APFC, it's just cheaper to do it like that. But anyway, i can agree with APFC being semi-useless in average (500 watt range) computer power supplies, but when you're talking kilowatts it starts to count.

When you're trying to squeeze 4kW out of a 230v circuit, a power supply with APFC won't trip a 20A breaker. A power supply without, will.

[370forlife]

Re: Digital power factor correction

I have a ATNG AP-500X that has universal input without APFC. Kind of funny as the unit is silkscreened to have APFC.

[PCBONEZ]

Re: Digital power factor correction

Back to the original post.

DigiKey, Mouser, Avnet have them. Avnet's cheapest.

Datasheets attached.

Cheers!
Toast

The Operating Frequency on those max's out at 70 kHz.
Lower switching frequency means bigger main transformer in PSU.

.

[everell]

Re: Digital power factor correction

The Operating Frequency on those max's out at 70 kHz.
Lower switching frequency means bigger main transformer in PSU.

.

Whaaaat??? The chip controls the APFC FET switching transistor. Its load is a big toroid coil, not the main switching transformer.

That chip is an itty bitty thing. Need to order a SOIC to DIP adapter just so you can get your hands on it! Digikey sells Aries adapter p/n 08-350000-10.

[Krankshaft]

Re: Digital power factor correction

That chip is an itty bitty thing. Need to order a SOIC to DIP adapter just so you can get your hands on it! Digikey sells Aries adapter p/n 08-350000-10.

Cool I didn't know they made SOIC to DIP adapters not good for the final product on a PCB of course. But very good for prototyping it on a breadboard.

[everell]

Re: Digital power factor correction

I have the chip already. So small I darn near didn't find it in the envelope. So I have ordered one of those adapters. That way I can solder the chip to the adapter, and plug the adapter into an 8 pin dip socket on my breadboard.

[everell]

Re: Digital power factor correction

Toasty is right......another everell project has been launched. I am using a discarded Bestec ATX-250 12Z to convert from what it is to one having APFC using this new CS1500 chip.

So far I have removed the two main capacitors and replaced with the one main capacitor. I have wound a booster coil and mounted it. And I have added the big .47 Mfd filter capacitor across the bridge rectifier. Picture attached.

Next is some "cut and paste" of circuit traces on the bottom of the board. Then I will prototype the breadboard using the new CS1500 chip.

[shovenose]

Re: Digital power factor correction

dood how cool

[everell]

Re: Digital power factor correction

I was a bit concerned as to how well the A6351 chip would perform the 5vsb function when the startup voltage across the main capacitor is only 160 volts rather than the 320 volts used in the usual doubler circuit. So today I did the basic wiring to hook up bridge rectifier, main capacitor, and 5vsb circuit. On power up, the main capacitor charged to 162 volts. The A6351 came up just fine giving 4.98 volts on the 5vsb line, and powering the supervisory chip such that the "Power Good" LED came on as expected. The feedback circuit voltage measured 14 volts, plenty to power the main pwm chip, and hopefully the new APFC chip also. So this first test before wiring the APFC components was a success.

[Toasty]

Re: Digital power factor correction

Impressive. Most impressive.

[PCBONEZ]

Re: Digital power factor correction

Congrats!

[shovenose]

Re: Digital power factor correction

Any updates to the project?

[everell]

Re: Digital power factor correction

After a week and a half vacation in Tucson, AZ to observe the annual Feast of Tabernacles, I am back on the project. Did a lot of "cut and paste" on the circuit traces on the main pc board. Then built the add on board with the new CS1500 chip.

[everell]

Re: Digital power factor correction

There simply was not enough room on the main pc board to add a heat sink, two power MOSFET transistors, and a switching diode. So I built an outboard circuit with these parts.

[everell]

Re: Digital power factor correction

This evening I put it all together and fired it up. The output voltage using the suggested feedback resistor values came to 425 volts. A little higher than expected. I will do some further experimentation to see if I can reduce that voltage to something more like about 385 volts.

The dark picture shows the psu tester LEDs lit while operating. The three green ones are the three rails, 3.3 volts, 5 volts, and 12 volts. The amber one is the 5vsb. the red one is the power good indicator.

The new chip may function great for better power factor correction, but the BIG problem with this circuit....and ALL APFC circuits I have worked on so far......the booster coil gets super hot. That means either a burn up over time, or a shorted coil at some point in the future.

Since so few technicians are willing to take a power supply apart and determine WHY it failed, I predict that we are going to be seeing lots of power supplies fail because of the heat generated in the booster coil of the APFC circuit.