Driver device and driving method for driving an LED unit

摘要

The present invention relates to a driver device and a corresponding driving method for driving a load (22), in particular an LED unit, said driver device comprising power input terminals (51, 52) for receiving a periodic supply voltage from an external power supply potentially including a dimmer for dimming said periodic supply voltage, power output terminals (53, 54) for providing a drive voltage and/or drive current for driving a load (22), a power stage (70a, 70b, 70c, 70d) coupled between the power input terminals and the power output terminals for controlling an input current received from said power input terminals to draw a high power from said external power supply in a first mode or to draw a low or no power from said external power supply in a second mode, said high power being higher than the power required for driving said load and said low power being lower than the power required for driving said load, wherein said power stage controls said input current to be in the second mode only for a percentage of half cycle periods of a number of subsequent half cycle periods of said supply voltage, and for providing said drive voltage and/or drive current to said power output terminals in said first mode, and an energy storage unit (90) coupled to said power stage for storing electrical energy provided at said power input terminals in said first mode and for providing stored electrical energy to said load via said power output terminals in said second mode.

主权项

1. A method, comprising:
receiving at an input of a driver a periodic supply voltage from an external power supply, providing at an output of the driver at least one of a drive voltage and a drive current for driving a load, alternately operating the driver in one of a first mode and a second mode, including:
in the first mode, controlling an input current received by the driver from the external power supply to draw a first power level from the external power supply, the first power level being greater than a power level required for driving the load, and supplying from the input current the at least one of the drive voltage and the drive current to the load, and further supplying electrical energy to charge an energy storage device; andin the second mode, controlling the input current received from the power input terminals to draw no more than a second power level from the external power supply, wherein the second power level is less than the power required for driving the load, and providing the at least one of the drive voltage and the drive current to the load from the energy storage device, wherein alternately operating the driver in one of the first mode and the second mode includes operating only in the first mode for a first set of half cycles of the periodic supply voltage, and operating only in the second mode for a second set of half cycles of the periodic supply voltage immediately subsequent to the first set of half cycles of the periodic supply voltage.