Electronic control device for a direct current electric motor having two supply terminals for a drive system operating in back-and-forth mode, and the application of such a device to a vehicle screen wiping system

A direct current electric motor having two power supply terminals, in combination with an electronic control device for controlling the operation of the motor in alternate forward and reverse directions of rotation, the electronic control device comprising:

• detecting means for detecting a command for automatic reversal of the forward and reverse directions of motor rotation;
• at least one end of travel sensor for generating said command for automatic reversal of the forward and reverse directions of motor rotation;
• a control circuit connected to said detecting means for receiving output signals from said detecting means and for producing a control signal in response thereto;
• a direct current power supply means having at least one polarity;
• and a controlled interrupter having terminals connected between one of the supply terminals of the motor and said one power supply means polarity, the controlled interrupter having a control electrode connected to said control circuit for receiving the control signal from said control circuit for opening said controlled interrupter and then slowly reestablishing conduction of said interrupter, whereby to reduce noise caused by the reversal of the direction of rotation of the motor, said control circuit having a ramp generator for producing a signal of ramp waveform which puts said controlled interrupter slowly, and in a controlled manner, into full conduction in response to said command for reversal, wherein said ramp generator generates said ramp signal after the instant at which said interrupter opens.