METHOD OF SOFT-STARTING A SWITCHING POWER SUPPLY CONTAINING PHASE-CONTROL CLIPPING CIRCUIT

摘要

A method of operating a power controller that converts a line voltage to an RMS load voltage includes a soft start in which a conduction angle of a phase- control clipping circuit is gradually increased to a steady state value that defines the RMS load voltage. The controller has a circuit with a time-based signal source that triggers conduction independently of line voltage magnitude and a transistor switch whose gate receives signals from the time-based signal source to trigger the circuit. When starting the power controller, a microcontroller increases the conduction angle of the phase- control clipping circuit in plural steps to provide the soft start.