Patent ID: 7042280

Claim:
An apparatus for controlling an output current (I OUT ) that is delivered to a load circuit by a power device, the apparatus comprising: a current sense circuit that is arranged to provide a sense signal that is responsive to the output current, wherein the current sense circuit is coupled to the load circuit such that the operating current of the apparatus does not dramatically rise when a short-circuit condition is present across the load circuit, wherein the current sense circuit comprises a first transistor that is series coupled to the load circuit via a resistor such that the sense signal corresponds to a voltage associated with the resistor, wherein the first transistor includes a control terminal that is biased in common with the power device; a first transistor circuit that is arranged to deactivate the power device when a short-circuit detection signal is asserted; a second transistor circuit that is arranged to couple a small current to the load circuit when the short-circuit detection signal is asserted such that the apparatus automatically returns to a normal operating mode when the short-circuit condition is removed from the load circuit, wherein the small current corresponds to a nominal level such that the energy loss is minimized during the short-circuit condition; and a differential comparator circuit that includes: a first input that is coupled to the load circuit, a second input that is coupled to the sense signal, and an output that is associated with the short circuit detection signal, wherein the comparator circuit is arranged to assert the short-circuit detection signal as a logic level when the sense signal indicates that the short-circuit condition is detected across the load circuit.