I am trying to design an inexpensive solar cell current-voltage tester for educational modules related to solar energy. The purpose of the circuit is to sweep an applied voltage across a solar cell and measure the current out. At the moment, I'm using an Arduino Nano microcontroller to program a DAC for the voltage sweep and to read the current. I am measuring the current as the voltage drop across a 0.1 ohm resistor between the solar cell and ground. I am using TLV4110 op amps to buffer the current in the solar cell from the DAC and to transform the voltage across the resistor to a useable value for the 0-5V analog inputs of the microcontroller. I am trying to attach a schematic of the diagram. The "DUT" in the diagram is the solar cell, and solar cells can be modeled as a current source (current is proportional to light intensity on the cell) in parallel with a diode.
Unfortunately, the TLV4110 has a pretty high "low-level output voltage", and it is very important that I be able to apply voltage to within mV of zero at high current. Is there an op amp that can handle 200+ mA and has a low-level output voltage in the mV range?
Thanks very much,
David