Phase dimming circuit and method

Abstract

The invention discloses a phase dimming circuit and method. The phase dimming circuit comprises a dimmer, a phase discrimination circuit and a drive circuit. The dimmer is used for generating a pulsemodulation alternating current, and the dimmer is used for outputting alternating current sine waves with narrow pulses at the phase phi and the phase phi + pi, wherein the duration t of the narrow pulses meets the condition that t is greater than or equal to 50 microseconds and less than or equal to 100 microseconds. The input end of a phase discrimination circuit is connected with the output endof the dimmer, and the phase discrimination circuit is used for outputting PWM square waves or direct current control levels according to the alternating current sine waves. The input end of a driving circuit is connected with the output end of the phase discrimination circuit, the output end of the driving circuit is connected with a light source power supply, and the driving circuit is used forcontrolling the output current of the light source power supply according to the PWM square wave or direct current control level. According to the phase dimming circuit of the technical scheme, due to the fact that the sine waves with the narrow pulse blocking function are adopted for transmitting the phase information, the periodic current mutation cannot be generated, a power grid cannot be greatly affected, and power devices in the dimming circuit can be protected.

Description

technical field [0001] The invention relates to the field of dimming lighting, in particular to a phase dimming circuit and a phase dimming method. Background technique [0002] The current dimming products mainly use the leading-cut dimming technology and the trailing-cut dimming technology. However, both front-cut dimming and trailing-cut dimming need to block the current loop, so that the grid current changes periodically, which not only affects the grid environment, but also easily causes damage to power devices. Contents of the invention [0003] The present invention aims to solve at least one of the technical problems existing in the prior art. For this reason, the present invention proposes a phase dimming circuit, which dims light by means of narrow pulse blocking, avoids periodic sudden changes in grid current, and can also protect power devices from being damaged. [0004] The invention also proposes a phase dimming method. [0005] The phase dimming circuit ...

AI Technical Summary

Problems solved by technology

However, no matter the front-cut dimming or the last-cut dimming, the current loop needs to be blocked, so that the grid current changes periodically, which not only affects the grid environment, but also easily causes damage to power devices.

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