Load driving device and driving method thereof

Abstract

The invention relates to a load driving device and a driving method thereof. The load driving device receives direct current input voltage, and reflects gate pulse width modulation signals to provide direct current output voltage to a light emitting diode load. A control chip in the load driving device is configured to provide a gate pulse width modulation signal with a first default duty cycle during bright operation of dimming operation to enable the light emitting diode load to respond to the direct current output voltage and fully open, and provide a gate pulse width modulation signal with a second default duty cycle during dark operation of dimming operation to enable the light emitting diode load to respond to the direct current output voltage and weakly open. The second default duty cycle is smaller than the first default duty cycle. The current of the light emitting diode load during bright operation is greater than the current of the light emitting diode load during dark operation.

Description

technical field [0001] The present invention relates to a load driving device, and in particular to a light emitting diode driving device and a driving method thereof. Background technique [0002] A conventional light emitting diode (Light-emitting diodes, LED) driving device is generally composed of a control chip, a power switch, an external circuit and the like. Wherein, the control chip can provide a driving signal to switch the power switch, so that the LED can emit light according to the current generated by switching the power switch. With the existing LED dimming (dimming) technology, in order to achieve high contrast, the general driving device adopts pulse width modulation (Pulse Width Modulation, PWM) dimming technology, the dimming principle is to adjust the PWM dimming signal The duty cycle (Dutycycle) length, control the time ratio of LED full bright and full dark, in order to achieve the purpose of dimming. [0003] Generally, in the application of LED ligh...

AI Technical Summary

Problems solved by technology

However, when the LED is dimmed in full darkness, the time for the LED to be on becomes shorter, and the time and energy that can be provided to the LED drive device are relatively reduced. Therefore, during the full dark period of the LED, the control chip in the LED drive device will It will fail to work due to insufficient power supply. Generally speaking, an external large capacitor must be connected to provide power to the control chip to support the entire dark period of the LED. However, if the capacitance is insufficient, the LED drive circuit will still stop working

In addition, increasing the capacitance will not only increase the process cost but also increase the required area of ​​the printed circuit board (PCB)

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