How can I change output voltage on DC converter? - Solved

[pwd]

I bought this converter (24-100V IN to 12V) but unfortunately it does not have an adjustable output voltage. Does anyone know how I could change the output voltage from 12.4V to ~14.2V?

Yellow = +12.4V out
Black = Ground
Red = Input Voltage

 

[scianiac]

Look up the datasheet on that little 8pin chip, probably have a example circuit, see if that matches the one on the board and change the needed resistor. May not be worth your time vs buying one with an adjustable output.

 

[pwd]

Look up the datasheet on that little 8pin chip, probably have a example circuit, see if that matches the one on the board and change the needed resistor. May not be worth your time vs buying one with an adjustable output.

Thank you. I wasn't even sure where to start. So that chip (IP6523S) will be used in similar devices (step down converters)? I've found a datasheet here: http://www.injoinic.com/wwwroot/uploads/files/20200220/c1b99d880c11200052b5a3a146584733.pdf

There is a sample schematic, but I'm not sure what to look for other possibly than the VOUT pin (number 5) and R1.

EDIT: added a better shot near the 8 pin chip:

 

[scianiac]

Well I'm certainly no expert here but I would follow VOUT on the board and see where it leads, I'm guessing it will lead to a voltage divider connected to the output. Replace that divider with a suitable potentiometer for instance and you can adjust the voltage all you want.

 

[amberwolf]

That^^^

If, like int he simiplified and application schematics in the datasheet, there isn't a voltage divider on the Vout, then you'd have to install one, cutting the trace from Vout to the actual voltage output of the system. Install the (5kohm to 10kohm, probably) potentiometer with one outer pin to the actual votlage output, the other to ground. The center pin (wiper) goes to the Vout pin. Before turning it on, set the pot to max, meaning turned all the way toward the actual voltage output connection end. Then very slowly adjust it towards teh ground end until the voltage output reads what you want it to.

 

[pwd]

Thanks to you both. I decided (guess) to replace R1 on the board (an SMD resistor labeled 123 or 12k ohms) with a pair of 10k trim pots in series since I didn't have many resistors on hand. I made sure to dial them in so it would be ~12K ohms when I attached them to the board.

It is working! I've got it outputting 14.35V after adjusting the pots! :thumb:



Also, I've never attempted to replace tiny resistors like that. What a job. I went and bought some good flux paste and practiced on some scrap boards before trying this.