LED control circuit and LED control method of passive dimming signal

Abstract

The invention discloses an LED control circuit for a passive dimming signal, comprising a power supply circuit, a dimming circuit, an LED circuit, a main control triode, a dimming setting circuit and / or a voltage regulating setting circuit; the dimming circuit includes a coupler, Comparator and integrator, the coupler is used to detect the PWM signal, the comparator is used to output the level signal to the integrator according to the voltage of the reverse input terminal and the positive input terminal, and the integrator is used to control the state of the main control transistor according to the level signal to adjust LED circuit; the dimming setting circuit is used to drive the base of the main control triode so that the base of the main control triode has a preset saturated open state; the voltage regulation setting circuit is used to adjust the reverse input terminal of the comparator according to the PWM signal and Positive input voltage. The invention also discloses an LED control method based on the LED control circuit. By adopting the present invention, the LED light source can be dimmed through the passive dimming signal, and the phenomenon of being in the dark can be 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] like 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 emerg...

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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