Electronics > Power/Renewable Energy/EV's

Who knows what kind of SMPS is this one ?

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--- Quote from: 2N2222A on December 06, 2022, 04:13:10 am ---So you changed those too, meaning you also changed the output stage capacitors in addition to the HV mains input ones?

--- End quote ---
Nope, as I wrote I only replaced the two HV electrolytic capacitors : 820uf/200V (replaced temporarily with 2x 470uF/200V, the only ones I had handy).
But I also took this opportunity to purchase and order a good ESR meter and will definitely replace the output stage caps if they turn to show a high ESR as you hinted.
(I also purchased HV 820uF caps coz my 2x 470uF are too low in the long run)


--- Quote from: madires on December 04, 2022, 06:26:16 pm ---Yes, but check if they are really connected to one wire of the primary winding.

--- End quote ---
Yes, I confirm they are.
Those two caps are OK though, I checked their capacitance and resoldered them in place.

When you power the circuit up .
Best is to not use the bias supply if it doesnt work...just switch in 12v, (or whatever ) from an external supply.
Also.....make an external board with a 1A (or low value) fuse, and an heavy  inrush resistor, eg 47R, 50W.
Always switch it on via the inrush resistor....then you can enable the PSU after you switch out the external inrush resistor.
Read the chip datasheet to see how to disable it
Or just disable it by switching out its vcc with the external vcc supply

Be very careful not to touch....everything, including the external boards is mains live and can in theory kill.

@faringdon :
Thanks alot for your following-up but the SMPS now works ...   :-+ !

I replaced the two HV caps with 2x 470uF/200V as the original ones (820uF/200V caps) showed very high resistances on the ESR meter.
I will later replace them again with higher capacitance values (820uF-1000uF) but for the time being these two 470uF do the job.

But your suggestions and advice are quite interesting though, at least to improve my own knowledge ;) :
- what do you exactly mean with don't use the bias supply (12V), what do you refer to ?
- also where would you insert the 1A+inrush resistor in the circuit ?

FYI, a basic diagram of this SMPS half-bridge topology can be drawn like that (very roughly ...) :

And the driving of the two Mosfets gates is based on a piggyback-mounted TL494/KA7500 PWM controller :

(as shown above, I managed to control the SMPS Iout by ways of adjusting R24 value)
Oh and by the way, I am very sorry for what happened to your country yesterday :-// !


--- Quote ---Oh and by the way, I am very sorry for what happened to your country yesterday
--- End quote ---
Thanks, i reckon Lloris payed his spurs team mate Kane to fire that penalty over......(OK, not really)

Anyway, you have a capacitor in series with your half bridge...there is much  to speak about that...i will come back later on it.


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