Short-circuit protection for voltage regulators

摘要

Circuits and methods for providing short-circuit protection in a voltage regulator are disclosed. A voltage regulator includes a pass switch, a voltage error amplifier, a driver circuit, and a short-circuit protection circuit. The pass element is coupled to a power supply and a load, and generates an output voltage in response to a drive signal. The voltage error amplifier generates an error voltage based on a difference of a reference voltage and the output voltage and the driver circuit generates the drive signal in response to the error voltage. The short-circuit protection circuit senses the drive signal and provides a high-resistance path to the driver circuit in a short-circuit event. In a short-circuit event, the high-resistance path clamps current in the driver circuit thereby clamping a voltage difference between the first and third terminals and thereby limiting a load current in the short-circuit event.

主权项

1. A voltage regulator, comprising:
a pass switch for electrically coupling a power supply with a load during an ON-state of the pass switch and for electrically decoupling the power supply from the load during an OFF-state of the pass switch, the pass-switch comprising a first terminal, a second terminal and a third terminal, the first terminal coupled to the power supply and the second terminal coupled to the load, the pass switch configured to generate an output voltage at the second terminal in response to a drive signal received at the third terminal; a voltage error amplifier comprising a first input terminal, a second input terminal and an output terminal, configured to receive a reference voltage at the first input terminal and the output voltage at the second input terminal, and further configured to generate an error voltage at the output terminal based on a difference of the reference voltage and the output voltage; a driver circuit coupled to the voltage error amplifier at the output terminal and to the pass switch at the third terminal, the driver circuit configured to generate the drive signal in response to the error voltage; and a short-circuit protection circuit coupled to the pass switch at the third terminal and configured to:
sense the drive signal received at the third terminal;provide a high-resistance path to the driver circuit during a short-circuit event of the voltage regulator in response to the drive signal, wherein the high-resistance path provided to the driver circuit enables clamping a current in the driver circuit thereby clamping a voltage difference between the first terminal and the third terminal and thereby limiting a load current in the short-circuit event; andprovide a low-resistance path to the driver circuit during a non short-circuit event.