| 摘要 |
The invention relates to lighting devices with light-emitting diodes organized in ramps arranged in parallel, each ramp including a certain quantity of light-emitting diodes arranged in series, the ramps being powered by a DC voltage of several tens of volts, called high voltage, the high voltage being generated by a step-up converter circuit from a low DC voltage of a few volts. The value of the voltage is controlled by the duty cycle of the step-up converter circuit, and the voltage is servocontrolled to a constant average value by a servocontrol device controlling the duty cycle. Each servocontrol device has several operating modes defined by a particular electronic addressing of the high voltage or by a defined number of ramps of lit diodes. To optimize the operation of the lighting device, the step-up converter circuit has discontinuous conduction and the servocontrol device includes several servocontrol electronic circuits linked to an electronic multiplexer, and each servocontrol electronic circuit being dedicated to a particular operating mode, the electronic characteristics of the servocontrol electronic circuits depending on the operating mode. The servocontrol electronic circuit is operational only when the operating mode is selected.
|
