Texas Instruments Incorporated
Current limit through reference modulation in linear regulators

Abstract:

A linear regulator system is described. The linear regulator system includes a linear regulator core circuit including a pass element adapted to provide an output voltage, and a voltage error amplifier circuit coupled to the pass element and adapted to regulate the output voltage to form a regulated output voltage, based on an output reference voltage. The linear regulator core circuit further includes a current limit circuit comprising a current limit switch element coupled to the voltage error amplifier circuit and adapted to selectively modulate the output reference voltage of the voltage error amplifier circuit to form a current limited reference voltage, based on a current limit control signal received at a current limit control terminal associated therewith, in order to limit a load current through the pass element from exceeding a predefined maximum allowable load current limit.