Slide 1 Slide 2 Slide 3 Slide 4 Slide 5 Slide 6 Slide 7 Slide 8 Slide 9 Slide 10 Slide 11 Slide 12 Slide 13 Product List
Motor Signal Chain Overview Slide 8

The diagram on this slide is of a motor using two in-line current shunt resistors for the control loop. The primary performance difference between low-side and in-line current sense amps is that in-line measurements need a wide common-mode voltage range and high common-mode rejection. In-line voltage levels are much higher than low-side voltage levels which operates near ground. In this case, the voltage drop across the in-line sense resistor is very small in comparison to the in-line voltage. In-line currents are continuous and relatively slow changing when compared to the fast switching low-side currents, so high gain bandwidth and fast slew rates are not required. Also, like the low-side amps, rail-to-rail input/output and low DC offset and low drift over temperature are important features to look for.

PTM Published on: 2011-06-15