Siemens Aktiengesellschaft

Continental Automotive Systems Corporation

Lothar Erle

Luis Roberto Togo Peraza

Michael Degen

An apparatus for providing protection to an electric circuit includes a P-channel MOSFET; a freewheeling diode coupled to a drain of the P-channel MOSFET and coupled to a load; and a charge pump coupled to a gate of the P-channel MOSEFT. In a normal operating mode, the charge pump receives a voltage from a voltage regulator, and is configured to multiply and reverses the polarity of the voltage to supply to the gate of the MOSFET. In a reverse battery operating mode, the charge pump receives no voltage from the voltage regulator to supply to the gate of the MOSFET causing the MOSFET to deactivate such that when the MOSFET deactivates, current is prevented from flowing through the freewheeling diode to protect the freewheeling diode.

Apparatus and method for reverse battery protection

A method for switching on an inductive load, in particular an ignition coil, whose current is intended repeatedly to reach a predefined variable end value at a respectively predefined variable time, includes measuring the time interval between the switching-on action and reaching at least one predefined intermediate value. This time interval and the at least one predefined intermediate value are used to calculate the anticipated time from switching on until the end value is reached. A following switching-on action is carried out at the calculated time before the respectively predefined time.

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Kelkheim, Germany

Lothar Erle