CC and CV leds are both lit at same time
CC and CV leds are both lit at same time
(OP)
Does anyone know why both CV and CC LED's are sometimes lit when using my power supply? Scope shows odd waveform whenever this happens. Otherwise, flat line DC, no waveform, everything fine. It usually happens when current limiting knob is just starting to have an effect. Seems like the transition from CV mode to CC mode overlaps and causes a freak out. I can make it go away by over-turning the setting, and then dialing back down. I'm keeping the supply, so looking for a fix... adding a diode or resistor or a left-handed capacitor or some such ;)
(I'm new here, not sure about including photos but giving it a try)
(I'm new here, not sure about including photos but giving it a try)





RE: CC and CV leds are both lit at same time
RE: CC and CV leds are both lit at same time
TTFN (ta ta for now)
I can do absolutely anything. I'm an expert! https://www.youtube.com/watch?v=BKorP55Aqvg
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RE: CC and CV leds are both lit at same time
RE: CC and CV leds are both lit at same time
That's my point exactly. But in dialing things in, invetiably I run into the point where the 2 controls overlap and the PS output freaks out, causing a potential disaster for delicate circuits. I'm determined to find a cure. It should be impossible for both LEDs to be lit at same time. The transition is flawed somehow.
RE: CC and CV leds are both lit at same time
RE: CC and CV leds are both lit at same time
It could be like a vibration, not locking in on one or the other state. Like an out of balance car tire vibrates at a specific RPM but is OK before and after. There is a simple solution to this... I just have to find it.
RE: CC and CV leds are both lit at same time
RE: CC and CV leds are both lit at same time
As the doctor said as I complained about the pain that occurred when I moved my arm thusly, "well, then don't move your arm thusly."
Perhaps you should explain WHY you need to do both and what the application is. Almost all circuits have variances in operating conditions, depending on modes and functions being exercised, so constraining both voltage and current is typically an unwise thing to do.
TTFN (ta ta for now)
I can do absolutely anything. I'm an expert! https://www.youtube.com/watch?v=BKorP55Aqvg
FAQ731-376: Eng-Tips.com Forum Policies forum1529: Translation Assistance for Engineers Entire Forum list http://www.eng-tips.com/forumlist.cfm
RE: CC and CV leds are both lit at same time
RE: CC and CV leds are both lit at same time
RE: CC and CV leds are both lit at same time
TTFN (ta ta for now)
I can do absolutely anything. I'm an expert! https://www.youtube.com/watch?v=BKorP55Aqvg
FAQ731-376: Eng-Tips.com Forum Policies forum1529: Translation Assistance for Engineers Entire Forum list http://www.eng-tips.com/forumlist.cfm
RE: CC and CV leds are both lit at same time
RE: CC and CV leds are both lit at same time
"Look at undershoot and overshoot on transitions. That is what I would be concerned about." Good point, the PS may be so crappy in the first place that I'd be better off using it for parts or to run christmas lights or something :)
Thanks for your input, I'm gonna check a few caps today to verify no obvious bad ones, and if time permits, maybe give those 2 multi-turn pots next to the Op-Amp a couple spins in both directions and see what happens. (I'll note the resistance settings before hand of course) Will update with anything new.
RE: CC and CV leds are both lit at same time
This does not compute; the Current Dial IS the current limit, so when you hit that point, you're telling the power supply that it's not allowed to increase the voltage to supply the power demand, and it's not allowed to increase the current either. That's a nonsense operating condition.
TTFN (ta ta for now)
I can do absolutely anything. I'm an expert! https://www.youtube.com/watch?v=BKorP55Aqvg
FAQ731-376: Eng-Tips.com Forum Policies forum1529: Translation Assistance for Engineers Entire Forum list http://www.eng-tips.com/forumlist.cfm
RE: CC and CV leds are both lit at same time
RE: CC and CV leds are both lit at same time
You would typically set the foldback, against a resistor load, to occur at a current somewhat higher than the worst-case current you expect to see in the circuit under development, then leave the current setting alone, until you wish to power a different circuit.
Your supply is clearly trying, to the best of its ability, to honor both of your requests for a particular voltage limit and a particular current limit, but you are confusing it by twiddling the knobs until it gets into a condition where both limits are starting to kick in, and it's oscillating between the two, undecided, or maybe vacillating would be a better word.
There is nothing 'wrong' or 'broken' with your supply; you are just confusing it.
Mike Halloran
Pembroke Pines, FL, USA
RE: CC and CV leds are both lit at same time