The most popular technique to measure current is with a current-sense resistor, shown here in this diagram as RSENSE. The basic principle of this approach is to amplify the voltage drop across the current-sense resistor by using an op-amp-based differential gain stage, and then to measure the resulting voltage. While discrete components can be used to build the amplifier circuit, integrated current-sense amplifiers have significant advantages over discrete implementations: better temperature drift, smaller PC-board (PCB) area, and the ability to handle wide common-mode ranges. The current sense amplifier device’s low input offset voltage, tight gain error, and low temperature drift characteristics allow the use of small-sense resistors for current measurements to improve power-supply conversion efficiency and accuracy of measurement.