Patent ID: 7564704

Claim:
A power supply controller comprising: A switching controller; a first circuit configured to form a first drive signal responsively to the switching controller to control a first transistor of a half-bridge to regulate a value of an output voltage formed by the power supply controller; a second circuit configured to form a second drive signal responsively to the switching controller to control a second transistor of the half-bridge; a first sense circuit configured to receive a bridge voltage formed by the half-bridge and to inhibit driving the first transistor responsively to the bridge voltage having a value that is less than a first value, the first sense circuit including a capacitor having a first terminal coupled to receive the bridge voltage and a second terminal, a diode having a cathode coupled to the second terminal of the capacitor and an anode coupled to a supply return, a transistor having a first current carrying electrode coupled to receive the bridge voltage, a second carrying electrode coupled to the second terminal of the capacitor, and a control electrode coupled to receive a signal from the first drive signal; and a second sense circuit configured to receive the bridge voltage and to inhibit driving the second transistor responsively to the bridge voltage having a value greater than a second value that is less than the first value.