Shunt and Current-to-Voltage Converter
Shunt is a resistor that carrying a very small value of resistance, normally 1 Ohm. Shunt usually takes important role in current measurement. In our famous equation,
|V = I * R|
when R = 1 ohm, voltage across that resistor must equivalent to current value. For example, if voltage across that resistor measured 1.5V, it must be 1.5A across that resistor as well due to resistance is only 1 ohm. Therefore, from here we are capable to develop a circuit that able to control the amount of current flow for our PSU.
That’s right, when we have voltage level that represents current value, we can develop a simple single-ended op-amp system to sense and capture difference between two points of shunt resistor. For this case we will use differential amplifier, as simple as we learn from textbook where Vout determine by:
|Vout = (R5/R4)*(V2-V1)|