Patent ID: 8232781

Claim:
A measuring device for measuring current flowing through a power transistor of a voltage regulator, the measuring device comprising: a first transistor adapted to mirror a current through the power transistor, the first transistor having a first conduction terminal, a second conduction terminal, and a control terminal, the first conduction terminal being coupled to an input voltage terminal and configured to be coupled to a first conduction terminal of the power transistor; a coupling circuit structured to couple the second conduction terminal of the first transistor to a second conduction terminal of the power transistor and to provide an output quantity corresponding to a current through the first transistor; an error amplifier circuit structured to compare the output quantity of the coupling circuit and a reference quantity and to output an error signal a driver circuit having an input coupled to the error amplifier circuit and an output configured to be coupled to a control terminal of the power transistor and structured to limit current through the power transistor in response to the error signal from the error amplifier circuit; and a reference quantity modification circuit configured to be coupled to the power transistor and structured to modify the reference quantity in response to determining that a voltage across the power transistor is less than a threshold voltage.