Load control device for a light-emitting diode light source

摘要

A load control device for controlling the intensity of a lighting load, such as a light-emitting diode (LED) light source, may include a power converter circuit operable to receive a rectified AC voltage and to generate a DC bus voltage, a load regulation circuit operable to receive the bus voltage and to control the magnitude of a load current conducted through the lighting load, and a control circuit operatively coupled to the load regulation circuit for pulse width modulating or pulse frequency modulating the load current to control the intensity of the lighting load to a target intensity. The control circuit may control the intensity of the lighting load by pulse width modulating the load current when the target intensity is above a predetermined threshold and control the intensity of the lighting load by pulse frequency modulating the load current when the target intensity is below the predetermined threshold.

主权项

1. A load control device for controlling an intensity of a lighting load, the load control device comprising:
a load regulation circuit configured to control a magnitude of a load current conducted through the lighting load, the load regulation circuit including a regulation transistor adapted to be coupled in series with the lighting load; and a control circuit operatively coupled to the regulation transistor of the load regulation circuit for pulse width modulating or pulse frequency modulating the regulation transistor to control the intensity of the lighting load to a target intensity; wherein the control circuit is configured to control the intensity of the lighting load by pulse width modulating the regulation transistor when the target intensity is above a predetermined threshold and control the intensity of the lighting load by pulse frequency modulating the regulation transistor when the target intensity is below the predetermined threshold.