A low-cost current sensor with a novel modulated interface (F-PWM)

Compared to conventional current sensors, the proposed topology is advantageous because of its high resolution throughout its full measurement range, thus reducing offsets to a minimum. This aim is reached through active offset compensation using an analog/digital chopper/de-chopper. A further advantage is the excellent suppression of 1/f noise and a low noise density (35 nV/√Hz) down to the DC-threshold. Common current sensors may be replaced with this technology whose one output is likewise analog. The power supply requirements are also far lower than for standard topologies as only a single supply is needed. The novel modulation method and therefore the current sensor, results for current control units a high performance. An AD-Converter is not more necessary for signal conversion. The measurement current is directly coded in a “digital current value”, which can be decoded and used for the control unit.