Conti Temic Microelectronic Gmbh

Temic Telefunken Microelectronic Gmbh

Ulrich Joos

Wolfgang Schulter

Erwin Kessler

Dieter Driendl

Manfred Fischer

Disclosed are apparatus and method for measuring electric current flowing through an inductive load energized by a half-bridge circuit with at least two semiconductor switches. The semiconductor switches are switched on and off in a complementary manner according to PWM. The apparatus comprises: a monitoring device determining the switched-on states and switched-off states of at least one of the at least two semiconductor switches; a synchronous measurement amplifier controlled by the monitoring device measuring voltage drop at the semiconductor switch during the switched-on state of the semiconductor switch and multiplying it to form multiplied voltage; and a synchronous voltage follower controlled by the monitoring device generating a voltage signal characteristic of the current in the inductive load, which in the switched-on state of the semiconductor switch follows the multiplied voltage and in the switched-off state of the semiconductor switch remains substantially constant or decreases according to a predefined profile.

Apparatus and method for measuring a current flowing through a PWM-controlled inductive load

A circuit arrangement is for operating at least one light-emitting diode LED in an electrical circuit at a service voltage greater than the forward voltage of the at least one light-emitting diode. The light-emitting diode is PWM-controlled. The circuit includes reactances that are connected in series at both connections of the light-emitting diode, an additional switching arrangement between the terminals, and a full-wave rectifier circuit, such that the circuit is protected against short-circuits on the service voltage and on ground while the LED can continue to be triggered.

Circuit arrangement for operating at least one light-emitting diode

A method for monitoring the opening and closing process in a system having at least one component moved by electric motor is described. During this process, the following process steps are provided:

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Nonnenhorn, Germany

Ulrich Joos