Circuit array for limiting a load current by reverse phase angle control

Abstract

A circuit array, adapted to be coupled to a load and a source of a main AC voltage, for reverse phase angle control whereby a current flow in the load is limited to a defined phase angle (.alpha.) of the main AC voltage, comprising the following components for sequential control of the reverse phase angle control: a switching element, connected to the load and coupled to the source of the main AC voltage, for actuating the current flow in the load; a time determining component; and an integrated circuit. The integrated circuit includes: an actuating circuit, connected to the time determining component, responsive to a first control signal for generating a ramp voltage, and responsive to a second control signal for selecting one of at least two predetermined temporal voltage curves for the ramp voltage; a synchronizing circuit, coupled to the source of the main AC voltage and connected to the actuating circuit, for detecting a zero crossing of the main AC voltage, for synchronizing the ramp voltage to the main AC voltage, and for generating the first control signal; an evaluation circuit, connected to the actuating circuit and the synchronizing circuit, for monitoring the ramp voltage during reverse phase angle control and for generating the second control signal and a third control signal; an output stage, connected between the evaluation circuit and the switching element, and responsive to the third control signal for controlling the switching element; and a voltage supply circuit.