Patent ID: 8013549

Claim:
Circuit for detecting a functional status of an electro-motor, the circuit comprising: a sensor; a detection unit; wherein the sensor is a part of the electro-motor; wherein the detection unit is adapted to detect the functional status of the electro-motor; wherein the functional status of the electro-motor is one of a turning functional status and a locking functional status; wherein the sensor further comprises a coil; wherein the coil is adapted such that a rotor of the electro-motor induces a counter electro-motoric force in the coil when it is turning; wherein the coil is a winding of a stator of the electro-motor; wherein the detection unit further comprises a differential amplifier; wherein the differential amplifier comprises a first and a second input; wherein the first input is connected to a supply voltage; wherein the second input is connected to the coil; wherein the differential amplifier further comprises a first output; wherein the differential amplifier is adapted to generate at the first output one of a first differential signal and a second differential signal; wherein the first differential signal corresponds to the turning functional status of the electro-motor; wherein the second differential signal corresponds to the locking functional status of the electro-motor; wherein the first differential signal and the second differential signal differ at a sample time point; wherein the sample time point lies in a sample time interval.