| Electronics > Repair |
| 18V/3A HY1503 PSU - weird CC/CV behavior while charging battery cells |
| << < (10/15) > >> |
| xavier60:
I added CC to my mock-up. Works fine with 10K for the compensation resistor and even with no capacitor. I by chance noticed that the 470pF across the CV opamp inputs was causing a 200KHz oscillation at higher currents. No problems with 120pF. |
| iMo:
This is 324's CC output with 120pF feedback (in mid of the CC range). CV wired as in the above schematics. When I disconnect its output from the 1N4007 output gets clean. |
| xavier60:
Try the 6n8 and 10K. The attenuation will be about 1000:1 at 2MHz. The only possible reason I can think off so far is that somehow there is too much inductance in series with the CS resistors. |
| xavier60:
I tried putting 200mV p-p of 2MHz through my output stage. Most of it gets blocked by the 10 ohm resistor at the Base of the 2N3055. I see about 10mV at the output. What are you loading with? |
| iMo:
The 10k ser 6n8 increases the amplitude almost twice (500mVpp). The load is a 10W ww (a white ceramic brick) resistor on aprox 80cm lab wires. The only thing which lowers the amplitude significantly (10x) is when I put my finger at the 324 output.. :D So there is a HF coupling somewhere. My o'scope is isolated via a trafo, but connecting its ground with psu's earth does not help. The probe is a Tek probe, 10x, grounded to the ground of the schematics. The tracks around the opamp were cut, the 3 red wires are in+ in- and out of the CC opamp. Rearanging them does not help. |
| Navigation |
| Message Index |
| Next page |
| Previous page |