Please explain PI Expert parameter "CC Threshold"

4 posts / 0 new

At least in the online version of PI Expert, there is a parameter "CC Threshold" and I am struggling to understand it. It seems to be the maximum voltage at which constant current can be delivered. But shouldn't the current limit work at all voltages up to the specified CV voltage? For example, say I design CV/CC supply with one 12 volt, 8 amp output (100 w). I can't set the CC Threshold higher than 5 volts. What does this supply do if loaded with an LED array with total Vf of, say, 10 volts?

Hi mark,

In what design topology and family exactly did you see the "CC Threshold" parameter? This will help explain the context of this parameter.

This was the online version of PI Expert. The design is a TOPSwitch-JX Flyback with a TL431 and optocoupler for feedback. There is no obvious current measurement means on the secondary side.

TitleSize
Design file from PI Expert2.15 MB

Hello Mark,

If you try hovering over the dialog box for the CC threshold, it would say "Voltage drop across secondary current sense circuit at CC characteristic". I believe the value here is the assumed voltage across the current sense resistor you will use in achieving CC regulation.

Thanks.