I have a working prototype of the current regulator. If you took a look at the previous post, I implemented a totem pole because of some stability problem on the Mosfet switching. It’s always a good idea to drive Power Mosfet with this kind of circuitry if you use an uC. But in that case it was not a Gate capacitance problem. It was a simple problem of decoupling capacitors… I forgot to put some caps on the Vcc rail, on the first switching the current was too high to keep a stable 5V Vcc, you can imagine…
+5V -> Switch -> Reset -> +5V -> Switch -> Reset…
First Pic \o/
For the moment I don’t have wired the Operationnal Amplifier. I just implemented the PWM part (for the pic18 and dspic version). For information here is the Voltage ripple measure with this version (no totem-pole).
Yellow Line: Mosfet Gate
The rise time is about 800 ns with some ripple on the Vout (200mV approx.)
I didn’t take a picture for this version, it’s a really messy bunch of wires ;) But here is the schematic (you can find the ltspice on my repository).
PCB etching seems to be a good idea \o/
There will be an integration in the XPLDuino project ! Take a look we are waiting for the new mainboard ;)
If you want all the data for this project you can get files here.