Switch light modulation circuit

Abstract

The invention discloses a switch light modulation circuit. The switch light modulation circuit comprises a power supply switch and a driving circuit, wherein the driving circuit comprises a power supply module, an energy storage module and a control module, the power supply module is used for converting an AC voltage outputted by an AC power supply into a DC voltage, the control module comprises a first switch tube and a control device, the control device is used for controlling on or off of the first switch tube to control the power supply module for charging the energy storage module or discharging of the energy storage module, the control device is sued for detecting discharging ending pulses of the energy storage module and controlling on or off of the first switch tube according to a wire current flowing through the first switch tube and the discharging ending pulses, and the control device is further used for determining closing of the power supply switch when no discharging ending pulses are detected within predetermined time segment, and the control device is closed. The switch light modulation circuit is advantaged in that brightness of light sources can be accurately adjusted, brightness of multiple light sources in control parallel with one same power supply switch can be simultaneously adjusted, and brightness non-consistency can be avoided.

Description

technical field [0001] The invention relates to switch dimming technology, in particular to a switch dimming circuit. Background technique [0002] With the enhancement of human awareness of environmental protection and energy saving, light emitting diodes (light emitting diodes, LEDs), as a new generation of semiconductor lighting devices, have been used more and more by virtue of their advantages such as high efficiency, low consumption, fast response, and long life, and have gradually become lighting devices. mainstream. At the same time, the brightness adjustment of LED has also become a real problem. Recently, switch segment dimming has been more and more recognized by the market. Switch segment dimming, as the name suggests, is to switch between different brightnesses through the closing and opening actions of ordinary switches. [0003] In the existing switch segment dimming control circuit, the brightness of the LED is controlled by controlling the on-off of the s...

AI Technical Summary

Problems solved by technology

However, due to the existence of the bypass capacitor of the LED and the bypass capacitor of the control chip, the power supply terminal of the control chip will not drop to zero volts immediately after the power switch is turned off, but there is a certain delay time

Therefore, if the switching power supply operates too fast (for example, the interval time is about 100ms), the control chip cannot detect the opening and closing of the power switch, so the on-off frequency of the switch tube will not be changed, that is to say, the brightness of the LED cannot be realized. adjust

[0004] In addition, when the same power switch controls multiple strings of LEDs connected in parallel, due to the differences in the bypass capacitors of each string of LEDs and the bypass capacitors of each control chip, the same power switch may be detected by some control chips when it is turned off and on. Detected but some control chips cannot detect it, which leads to the adjustment of some LEDs to the next level of brightness, while other LEDs remain at the original level of brightness, resulting in different brightness of the LEDs.

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