Thread: ebay power supply
It may take me a couple of days to work out the answer to the volts. Its a TI UCC2985 phase-shifting PWM controller driving 4 x F740 500V 20A HexFETs in a full-bridge, running at 340vDC supply, driving the output transformer, the output being rectified by two BYT16P dual fast 20A rectifiers. Feedback from output to PWM is via a pair of opto-isolators. As such it is not far different to the reference circuit for the 2985 PWM but so far not been able to identify the actual voltage regulation mechanism.
There are a pair of FA3624 PWM controllers on a daughter board each driving an FP460L hexfet as a single ended flyback converter to provide logic voltages of 5v and 12v (I'm guessing based on the other chips around there, but it would seem logical).
There is another daughter board with SMT parts on that is made in UK (rest is made in Germany) which suggests this was bought in. Havent been able to fathom its purpose yet.
check the Tec doc out on the listing page irving.
"500W Telecommunication 19“- Module"
16-07-2009 #14TI UCC2985 phase-shifting PWM controller driving 4 x F740 500V 20A HexFETs in a full-bridge, running at 340vDC supply, driving the output transformer, the output being rectified by two BYT16P dual fast 20A rectifiers. Feedback from output to PWM is via a pair of opto-isolators. There are a pair of FA3624 PWM controllers on a daughter board each driving an FP460L hexfet as a single ended flyback converter to provide logic voltages
Thanks for the investigations Irving - i've got a couple more weeks of fiddling with leadscrew and alignment then I think I'll suck it and see what happens at 42V. (unless your reverse engineering gets finished before my machine)(possible)
PS. cheers for the ebay spades link Hank - i'm nowhere near Maplin :(
I emailed the manafacturer (Minebea) to see if they had a schematic, here's their reply...
thank you for your request.
Sorry to tell you that NMB Minebea gave up that business years ago. No more drawings, spare parts or schematics available anymore,
Last edited by Lee Roberts; 20-07-2009 at 11:09 PM.
So Kip's only got 5 years warranty left.
.John S -
Well I managed to get the power supply wired up and it does what it says on the tin... no noise, no fuss, just 500w of power....
The variable output is, well, variable... and it doesn't get switched off...it sits at 42v when the 'inhibit' line below 5v or above 11v, although the SysOut line does switch off when out of regulation.
Also needs no load resistor.... works happily with no significant load.
Will continue to investigate....
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