LED control circuit and LED control method for passive dimming signal

Abstract

The invention discloses an LED control circuit of a passive dimming signal. The LED control circuit comprises a power supply circuit, a dimming circuit, an LED circuit, a main control triode, a dimming setting circuit and / or a voltage regulation setting circuit, wherein the dimming circuit comprises a coupler, a comparator and an integrator, the coupler is used for detecting PWM signals, the comparator is used for outputting level signals to the integrator according to the voltage of a reverse input end and the voltage of a forward input end, the integrator is used for controlling the state ofthe main control triode according to the level signals so as to adjust the LED circuit, the dimming setting circuit is used for driving the base electrode of the main control triode to enable the base electrode of the main control triode to have a preset saturated opening state, and the voltage regulation setting circuit is used for regulating the voltage of the reverse input end and the forwardinput end of the comparator according to the PWM signals. The invention further discloses an LED control method based on the LED control circuit. According to the invention, dimming can be carried outon the LED light source through the passive dimming signal, and the phenomenon of darkening is avoided.

Description

technical field [0001] The invention relates to an LED control circuit based on a passive dimming signal and an LED control method based on the LED control circuit. Background technique [0002] Pulse Width Modulation (PWM) is a very effective technology that uses the digital output of a microprocessor to control analog circuits, and is widely used in many fields such as measurement, communication, power control and conversion, and LED lighting. [0003] In the field of lighting, most PWM dimming on the market is dimming with strobe. [0004] Such as figure 1 As shown, the principle of the existing LED control circuit based on PWM dimming is: convert the PWM signal into 0-10V analog dimming after passing through the integrating circuit. However, the circuit needs to set the default brightness when starting up. In the dark and when the dimming controller is damaged, the circuit is in the state of turning off the light, so that the user cannot perform maintenance or other em...

AI Technical Summary

Problems solved by technology

However, the circuit needs to set the default brightness when starting up. In the dark and when the dimming controller is damaged, the circuit is in the state of turning off the light, so that the user cannot perform maintenance or other emergency treatment in the dark state.

[0005] Therefore, the existing LED control circuit cannot meet the needs of users

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