Hi,
I am working on a design that uses an LM25117 controller. The design calls for 0 to 6amps and the output voltage with different presets ranging from 6volts to 22.5 volts.
The way to control the output voltage has already been implemented. It consists of front panel DIP switches that control small mosfets that lowers the bottom resistor on the feedback voltage divider. This is working really nice and stable. This trick came from here (a TI engineer help).
The issue that I have is erratic switching of the high side mosfet. It has a ton of ringing and I also see sub harmonic oscillations (a large pulse, a small pulse and again a large). On the output as an example when configured for 6 volts output, I see almost 1 volts of ripple and when drawing more than 3 amps, the controllers shutdown.
So before getting deep into investigating this issue, is it feasible for this controller to have a design that would support such large voltage change without changing the compensation network values?
The load current will vary from 0 up to 6 amps with a very fast rate. This design is for a led strobe controller.
thank you
