Patent ID: 7525783

Claim:
A driver circuit for an actuator, comprising: an actuator circuit for charging and discharging the actuator, wherein the actuator is connected in said actuator circuit; a transformer having a primary winding and a secondary winding, said secondary winding connected in said actuator circuit; a first measuring device for measuring a first electrical current flowing through the actuator, said first measuring device having a first measurement resistor connected in series with the actuator; a second measuring device for measuring a second electrical current flowing in said actuator circuit before or after the actuator, said second measuring device having a second measurement resistor connected in series with said secondary winding of said transformer; a third measuring device for measuring an electrical voltage in said actuator circuit during a charging process; a comparator unit connected to said first, second, and third measuring devices, said comparator unit being configured to effect a comparison between the first and second electrical currents, and to generate a diagnostic signal in dependence on the comparison and in dependence on the electrical voltage measured by said third measuring device, the diagnostic signal taking on one of at least three different values depending on the comparison between the measured currents, in order to distinguish between a ground short circuit, a short circuit to a supply voltage, and an error-free state, respectively.