Patent ID: 6577482
Filing Date: 2003-06-10
Classification: H02H

Abstract:
A protective circuit for a series circuit of a power semiconductor and an inductive load, an output stage of the power semiconductor being switchable on and off depending on a predefined setpoint value of a pulse-width modulated control signal, the protective circuit comprising:a charging pump; a freewheeling circuit connected in parallel to the inductive load, the free wheeling circuit including a freewheeling diode connected in series to a reverse polarity protection semiconductor switch, the reverse polarity protection semiconductor switch being made non-conducting via the charging pump when a supply voltage polarity is reversed; and an arrangement for monitoring a point in one of the freewheeling circuit and the series circuit for at least one of a voltage and a current indicating a fault in the freewheeling circuit, and for initiating a shut-off of a control of the output stage of the power semiconductor using the at least one of the voltage and the current indicating the fault.