| Electronics > Projects, Designs, and Technical Stuff |
| Lab Power Supply - The Lost Current |
| << < (5/26) > >> |
| Damianos:
I lost the communication! If someone gives me an algorithm, to decode the messages, it may be reestablished! |
| TimNJ:
Try a "diode-OR" to switch between the CV and CC control loops. This is a common and effective way to implement constant current limiting on a "normally CV" power supply. Check out the attached schematic of an HP6214A lab power supply. Also check out this Keysight article: http://powersupply.blogs.keysight.com/2012/07/how-does-power-supply-regulate-its.html |
| xavier60:
There is a 5W 0.68 ohm resistor on the regulator PCB. I can't see the marking of the resistor next to it? Are these the shunt resistors? |
| radoczi94:
--- Quote from: TimNJ on February 02, 2018, 05:16:56 am ---Try a "diode-OR" to switch between the CV and CC control loops. This is a common and effective way to implement constant current limiting on a "normally CV" power supply. Check out the attached schematic of an HP6214A lab power supply. Also check out this Keysight article: http://powersupply.blogs.keysight.com/2012/07/how-does-power-supply-regulate-its.html --- End quote --- Thanks, will try it. Edit: One thing came into my mind. I am not shure, that I can put a diode in series with the CV opamp. What I could do is to move the diode on the CV opamp output (D7) and tie it's anode to the driver transistors' (Q4) base. --- Quote from: xavier60 on February 02, 2018, 12:01:13 pm ---There is a 5W 0.68 ohm resistor on the regulator PCB. I can't see the marking of the resistor next to it? Are these the shunt resistors? --- End quote --- Yes, it was in there, when I took the picture. When I put those 0,68R resistors,then I realised, that the "missing" 2 amps is more or less linear with the output load current. |
| xavier60:
Don't modify it until you have found a definite reason for the problems. Have you checked for oscillations? When you checked the regulator PCB for a possible short bypassing the shunt, did you have all of the wires connected? --- Quote from: radoczi94 on February 02, 2018, 09:51:56 pm --- --- Quote from: TimNJ on February 02, 2018, 05:16:56 am ---Try a "diode-OR" to switch between the CV and CC control loops. This is a common and effective way to implement constant current limiting on a "normally CV" power supply. Check out the attached schematic of an HP6214A lab power supply. Also check out this Keysight article: http://powersupply.blogs.keysight.com/2012/07/how-does-power-supply-regulate-its.html --- End quote --- Thanks, will try it. Edit: One thing came into my mind. I am not shure, that I can put a diode in series with the CV opamp. What I could do is to move the diode on the CV opamp output (D7) and tie it's anode to the driver transistors' (Q4) base. --- Quote from: xavier60 on February 02, 2018, 12:01:13 pm ---There is a 5W 0.68 ohm resistor on the regulator PCB. I can't see the marking of the resistor next to it? Are these the shunt resistors? --- End quote --- Yes, it was in there, when I took the picture. When I put those 0,68R resistors,then I realised, that the "missing" 2 amps is more or less linear with the output load current. --- End quote --- |
| Navigation |
| Message Index |
| Next page |
| Previous page |