Dimming circuit

Abstract

The invention discloses a dimming circuit, which comprises a demodulation module, a verification module and a dimming signal generation module. A control signal for a driving module is transmitted in a mode of transmitting a data frame, so that the driving module is controlled to act on the basis of the control signal to change the current passing through a lamp, and the brightness of the lamp is further changed. Compared with an analog signal, the data frame form is not easily interfered by the outside. Compared with a PWM signal obtained through chopping, the adjustment mode of the data frame is simpler and more flexible, and flashing is effectively avoided. In addition, the data frame comprises a data code and a check code, and the transmitted data code can be corrected, so that a lamp is prevented from being controlled on the basis of a wrong data code, and the control precision of the brightness of the lamp can be improved.

Description

technical field [0001] The invention relates to the field of lighting control, in particular to a dimming circuit. Background technique [0002] At present, in addition to lighting up LED (light-emitting diode) lamps through switches, the demand for lighting also needs to realize dynamic adjustment of the brightness of LED lamps. Optical technologies include the following: [0003] 1) PWM (Pulse width modulation, pulse width modulation) pulse width direct dimming, usually by applying PWM signals with different duty ratios on the dimming interface of the LED driver chip (PWM signals are realized by chopping), through Adjust the PWM signal to adjust the output current of the LED driver chip, so as to realize the adjustment of the brightness of the LED lamp. [0004] 2) Analog dimming. Usually, different analog voltages are applied to the dimming interface of the LED driver chip. The LED driver chip adjusts the constant current reference signal based on the analog voltage or ...

AI Technical Summary

Problems solved by technology

[0006] However, when the PWM signal is directly generated by chopping to adjust the brightness of the lamp, it is easy to encounter the problem of dimming dead zone, that is, when the duty cycle of the PWM signal changes, the number of power switching cycles in one cycle of the PWM signal does not change No change, resulting in the output current not responding to the dimming action, that is, the dimming curve is not linear enough, and the actual experience is not good

In addition, when an analog voltage is used to adjust the brightness, etc., the process of transmitting the analog signal to the dimming interface of the LED driver chip is susceptible to external interference, and there may also be a problem of insufficient dimming depth. Among them, the dimming depth The disadvantage is that for application scenarios that require extremely low brightness, it is relatively difficult for the system to process tiny analog signals (and the small signals themselves are more likely to be interfered), which may result in the inability to generate a relatively low output current

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