Patent ID: 8680787
Filing Date: 2014-03-25
Classification: H05B

Abstract:
1. A load control device for controlling the intensity of an lighting load, the load control device comprising: a power converter circuit operable to receive a rectified AC voltage and to generate a DC bus voltage; a load control circuit operable to receive the bus voltage and to control the magnitude of a load current conducted through the lighting load, the load control circuit comprising a controllable-impedance circuit adapted to be coupled in series with the lighting load; and a controller operatively coupled to the power converter circuit for adjusting the magnitude of the bus voltage to a target bus voltage, so as to control the magnitude of a controllable-impedance voltage generated across the controllable-impedance circuit, the controller operatively coupled to the load control circuit for generating a drive signal for controlling the controllable-impedance circuit to thus adjust the magnitude of the load current through the lighting load; wherein the controller is operable to control both the magnitude of the load current and the magnitude of the controllable-impedance voltage to adjust the intensity of the lighting load, the controller operable to control the magnitude of the controllable-impedance voltage by simultaneously maintaining the magnitude of the drive signal constant and adjusting the target bus voltage.