Apple Inc.
Reverse current protection circuit

Abstract:

A circuit and method for protecting from reverse current is disclosed. A reverse current protection circuit is coupled to a pass transistor of power circuitry (e.g., a power switch or voltage regulator), the pass transistor being coupled between first and second voltage nodes, the first voltage node being coupled to a power supply circuit. The reverse current protection circuit includes a sensing circuit that is configured to sense an amount of reverse current flowing through the pass transistor (from the second voltage node to the first voltage node). Responsive to the amount of reverse current exceeding a threshold value, the reverse current sensing circuit activates a shunt circuit, which redirects at least some of the reverse current to a reference node (e.g., ground).