Patent ID: 7009403

Claim:
A circuit arrangement for controlling and detecting a load current through a load, the circuit arrangement comprising: a load transistor having a control terminal, a load path, a first load path terminal and a second load path terminal, the load being connected in series with the load path of the load transistor to define a series circuit, this series circuit being connected between terminals for a supply potential and a reference potential; at least one auxiliary transistor having a control terminal, a load path, a first load path terminal and a second load path terminal; a current measuring circuit having a first and second input respectively connected to the first load path terminal of the load transistor and to the first load path terminal of the at least one auxiliary transistor and having an output, at which a signal dependent on the load current can be tapped off; a drive unit connected to the control terminal of the load transistor; at least one second auxiliary transistor, which is of identical type to the at least one auxiliary transistor, the at least one second auxiliary transistor having a control terminal, which is controllably connected to the control terminal of the load transistor, and having a load path; switching means for controllably connecting the load path of the at least one second auxiliary transistor in parallel with the at least one auxiliary transistor, depending on the load current or depending on a load path voltage obtained across the load path of the load transistor; and detection means that detect if the load current falls below a threshold and thereupon generate an output signal that is applied to the switching means.