Hi,
In our project we need to build an efficient tuneable current source with a nominal current of 5A and tenable in range 1A to 10A. My idea is to use a synchronous switched buck converter and manipulate the feedback loop for current regulation and control. The ADP1853 seems to be a good candidate for that. However, I am not able to build a stable loop with that regulator. The source is a diode with quite a long linear range (at 1A/5A, the voltage across the diode is about 1.45V/1.8V). The allowed current ripple of the source cuurent is about 1mA max.
I tried two possible solutions with were both unstable:
1) A simple arithmetic with OpAmps: Measure the current via a shunt resistor and amplify / subtract a set voltage / add 0.6V / connect to FB pin. Compensation was difficult here as I don't know how to calculate it in this scenario.
2) Measure the current via a shunt that is place after the inductor and before the output capacitor. Add a comparator that compares it to a set voltage and feed back to the COMP pin.
Does anyone has experience in such a design and could give me a reference to papers or a suggestion to calculate or evaluate the circuit in more detail?
