Patent ID: 8525452

Claim:
Circuit for detecting a functional status of a stepper electro-motor, having a plurality of stator windings connected to a supply voltage, the circuit comprising: a sensor comprising one of the windings of the stator of the electro-motor; a detection unit comprising a differential amplifier; 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 winding is adapted such that a rotor of the electro-motor induces a counter electro-motoric force in the winding when it is turning; wherein the differential amplifier comprises a first and a second input; wherein the first input is connected to the supply voltage; wherein the second input is connected to a phase of the winding of the stator such that loading a current in the phase let flow a current from the supply voltage to the phase through the winding; wherein the functional status of the electro-motor is one of a turning functional status and a locking functional status.