Driving device and method for driving a load, in particular an LED assembly

Abstract

Driver device and a corresponding driving method for driving a load, in particular an LED assembly comprising one or more LEDs. To provide a better performance, better cost-efficiency, improved power factor and reduced losses, a driver device (1, 1', 2, 2') is provided comprising a rectifier unit (10) for rectifying a received AC supply voltage (VS), load terminals (20) for providing a drive voltage (VL) and / or a drive current (IL) for driving said load, a capacitive storage unit (30) coupled between said rectifier unit and said load terminals for storing electrical energy provided by said rectifier unit and providing electrical energy to said load, and a bridge switching unit (40); coupled between said rectifier unit and said load for switching said capacitive storage unit into a load current path from said rectifier unit to said load terminals with a desired polarity and for switching said capacitive storage unit out of said load current path.

Description

technical field [0001] The invention relates to a driver device for driving a load, in particular an LED assembly comprising one or more LEDs, and a corresponding driving method. Background technique [0002] Light-emitting diodes (LEDs) are changing the lighting world. Its high and still increasing luminous efficacy, its long life, its small form factor, its low weight, its robustness, its ease of manufacture, etc. set the stage for the lighting industry to switch from incandescent lamps. The driving force of LED lights. However, the non-linear (nearly exponential) I-V curve of the LED, its low operating voltage (several volts) and its fast current-to-light output transfer response are critical when the lamp will be powered from mains voltage (eg 115V AC or 230V AC). A number of problems arise including light output flicker and voltage imbalance. [0003] Ideally, a DC must be supplied to the LED because the transfer from current to light output is nearly linear. One so...

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Problems solved by technology

[0006] All of these TLD systems have a common disadvantage: no light output if the (rectified) mains voltage drops below the voltage of the "shortest" high voltage LED string

[0010] Adding a fill-in capacitor helps maintain the light output around the zero crossing of the mains voltage (reduced flicker), but creates dimmer problems like multi-triggering because its discharge current is not passing through the mains branch

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