I'm working on a variable bench power supply design. It has variable
voltage out and variable current limit. Right now the current limit is
implemented with an op-amp circuit. The voltage and current set point
is being supplied by two DAC (MCP4922) outputs, controlled by a dsPIC.
I starting thinking: the dsPIC is already monitoring current draw via
its A/D and an instrumentation amp, why not do current limiting in
software? Essentially I check the current draw of the load against the
set point, and vary the output voltage accordingly using a PID
algorithm. The dsPIC A/D is 100K samples/sec.
I have a gut feeling that this method will be vastly inferior to the
traditional analog limiting. Anyone have experience with this?
voltage out and variable current limit. Right now the current limit is
implemented with an op-amp circuit. The voltage and current set point
is being supplied by two DAC (MCP4922) outputs, controlled by a dsPIC.
I starting thinking: the dsPIC is already monitoring current draw via
its A/D and an instrumentation amp, why not do current limiting in
software? Essentially I check the current draw of the load against the
set point, and vary the output voltage accordingly using a PID
algorithm. The dsPIC A/D is 100K samples/sec.
I have a gut feeling that this method will be vastly inferior to the
traditional analog limiting. Anyone have experience with this?