Short circuit fault protection for a regulator

A method of controlling a voltage regulator, comprising:

• receiving a reference voltage at a first input of an error amplifier and a feedback voltage at a second input of the error amplifier;
• comparing the reference voltage with the feedback voltage for driving a power transistor of the voltage regulator;
• comparing an output voltage of the voltage regulator with a fault reference voltage;
• and
• in response to determining that the output voltage of the voltage regulator is less than the fault reference voltage:
• driving the power transistor using an internal node of the error amplifier by changing states of a first switch and a second switch;
• and
• supplying the reference voltage to both the first and second inputs of the error amplifier by changing states of a third switch and a fourth switch.

A system comprising:

• an error amplifier configured to control an output current of a voltage regulator, the error amplifier having a first input, a second input, an output, and an internal node, a reference voltage being coupled to the first input;
• a transistor configured to supply the output current;
• a voltage divider circuit configured to provide a feedback loop over the second input of the error amplifier;
• and
• a modification stage configured to limit the output current during a fault condition, the modification stage including:
• a first switch coupled between the output and the transistor;
• a second switch coupled between the internal node and the transistor;
• a third switch coupled between the first input and the second input;
• a fourth switch coupled between the second input and the voltage divider circuit;
• and
• a monitoring stage configured to:
• compare an output voltage of the voltage regulator with a fault reference voltage;
• determine that the output voltage is less than the fault reference voltage;
• and
• in response to determining that the output voltage is less than the fault reference voltage, detect the fault condition and generate a control signal to control states of the first, second, third, and fourth switches.