Led driving apparatus and operating method thereof

Abstract

A LED driving apparatus and an operating method thereof are disclosed. The LED driving apparatus includes an output stage, an input resistor, a plurality of voltage dividing resistors, and a control circuit. A first voltage dividing resistor, a second voltage dividing resistor, and a third voltage dividing resistor are coupled between an input voltage and ground in series to divide the input voltage. The control circuit senses a first voltage signal, a second voltage signal, and a third voltage signal between the first voltage dividing resistor and the second voltage dividing resistor, between the second voltage dividing resistor and the third voltage dividing resistor, and the input resistor respectively, and adjusts a setting voltage signal according to the first voltage signal, the second voltage signal, and the third voltage signal.

Description

technical field [0001] The present invention is related to the driving of light-emitting diodes, in particular to a driving device of light-emitting diodes and its operation method. Background technique [0002] Generally speaking, the operating principle of the traditional AC-to-DC type LED driving circuit is to use an AC to DC converter (AC to DC converter) to generate the cross voltage (input Voltage) to drive the light-emitting diode to emit light, and at the same time, a current source circuit is set at the lower end of the light-emitting diode to control the fixed current flowing through the light-emitting diode to the ground terminal, thereby stabilizing the luminance of the light-emitting diode. Since the input voltage is a rectified signal, not a DC voltage, it needs to be driven by a light-emitting diode driving circuit, thereby achieving a higher PF power factor and luminous efficiency. [0003] However, since the set voltage output from the set voltage generator...

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Problems solved by technology

[0003] However, since the set voltage output from the set voltage generator in the prior art to the current source circuit at the lower end of the light-emitting diode varies with the input voltage, as Figure 1A to Figure 1C As shown, from the waveform diagram of its input voltage, light-emitting diode current and power consumption, it can be seen that: the light-emitting diode current (ILED) will change with the input voltage. When the input voltage becomes larger, the light-emitting diode The current also increases accordingly, which leads to the inaccurate current of the light-emitting diode current under different input voltages (high input voltage VH and low input voltage VL), that is, the problem of poor input voltage regulation (Line Regulation)

In addition, since the voltage and current of the current source circuit arranged at the lower end of the light-emitting diode will increase, the power consumption will be too large, resulting in the problem of overheating.

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