LED driver for powering an LED unit from a electronic transformer

摘要

An LED driver comprising a power converter for powering an LED unit and a control unit for controlling the power converter is provided. The power converter comprising an input terminal for receiving a rectified AC supply voltage, and an output terminal for supplying a current to the LED unit, and the control unit comprising —an input for receiving a supply signal representative of the supply voltage and —an output for providing a control signal to the power converter The control unit is further arranged to: —determine the control signal for controlling the power converter based on the supply signal, and —control the power converter to supply the current to the LED unit based on the control signal, the current being amplitude modulated in synchronism or in phase with the rectified AC supply voltage.

主权项

1. An LED driver comprising:
a power converter for powering an LED unit; a control unit for controlling the power converter; the power converter comprising: an input terminal for receiving a rectified AC supply voltage, and an output terminal for supplying a current to the LED unit, the control unit comprising an input for receiving a supply signal representative of the rectified AC supply voltage received by the input terminal of the power converter, and an output for providing a control signal to the power converter, whereby the control unit is arranged to: determine the control signal for controlling the power converter based on the supply signal, and control the power converter to supply the current to the LED unit based on the control signal, the current being amplitude modulated in phase or in synchronism with the rectified AC supply voltage, wherein a peak value of the current is, in use, varied according to the amplitude of the rectified AC supply voltage, whereby the variation is applied gradually by only adjusting a current level during a comparatively small part of a period of the rectified AC supply voltage per period of the rectified AC supply voltage.