Coil short circuit protection in dc-dc converters

Abstract

Circuitry for detecting a short across an inductor of a DC-DC converter includes a decoupling-circuit coupled between an inductor-terminal and an intermediate-node that, when activated, generates a detection-voltage (representative of voltage at the inductor-terminal) at the intermediate-node. A logic-circuit has an input coupled to the intermediate-node and an output generating a detection-signal. The detection-signal is asserted when the detection-voltage is closer to an input-voltage to the DC-DC converter than ground but is deasserted when the detection-voltage is closer to ground. Control-circuitry, at the beginning of a high-side conduction-phase, activates the decoupling-circuit and delays for a delay-period. After expiration of the delay-period and in response to the detection-signal being asserted, the control-circuitry completes the high-side conduction-phase. After expiration of the delay period and when the detection-signal is deasserted, the control-circuitry ceases the high-side conduction-phase of the DC-DC converter without completing the high-side conduction-phase and prevent beginning of a low-side conduction-phase.