Regulator with short circuit protection

A deflection circuit coupled to a deflection winding produces scanning current in the winding. A deflection rate voltage is developed at a first terminal of the deflection circuit. A source of operating voltage supplies energy to the deflection circuit, and a sensing circuit coupled to a source of voltage representative of an energy level in the deflection circuit produces an error signal for a control circuit that provides first and second control signals. A controllable switch coupled to the source of operating voltage and the first terminal provides operating current to the deflection circuit through the controllable switch. A first portion of the deflection rate voltage, under normal conditions, commutates off the controllable switch. The first control signal, coupled to a control terminal of the switch, switches the controllable switch into conduction, for modulating, under normal operating conditions, the duration of conduction of the controllable switch during each deflection cycle, thereby regulating the supply of energy coupled to the deflection circuit. The second control signals turn off the controllable switch under fault conditions when the deflection rate voltage fails to commutate off the controllable switch prior to the occurrence of the second control signals.