Control method and controller

Abstract

The invention discloses a control method and a controller. The control method is applied to a silicon controlled LED dimming power supply, and in each work cycle of the power supply, the control method comprises the following steps of: a voltage conversion step, specifically, converting a voltage VB representing the magnitude of a bus voltage into a differential voltage V1; a zero-crossing detection step, specifically, detecting the voltage VB, and outputting a zero-crossing signal Vz after detecting that the voltage VB is reduced from high to low; a counting step, specifically, receiving the differential voltage V1, performing resetting when receiving the differential voltage V1, starting counting through a timing reference, and outputting a real-time counting value; a conduction angle detection step, specifically, receiving the zero-crossing signal Vz, and when receiving the zero-crossing signal Vz, collecting a counting value output at the moment in the counting step, and recording the counting value as Count3; an LED current threshold value adjusting step, specifically, generating a reference voltage according to control signals; and a constant current step, specifically, adjusting the magnitude of power supply output driving current according to the reference voltage. According to the control method, in each work cycle of the power supply, the control signals are alternately output according to a first rule or a second rule. According to the control method and the controller of the invention, the stroboflash of an LED can be avoided, and dimming can be realized at the same time.

Description

technical field [0001] The invention relates to the field of LED dimming power supplies, in particular to the control of silicon-controlled LED dimming power supplies. Background technique [0002] Early lighting generally used incandescent lamps, which realized lighting by generating light through resistance wire heating. In order to meet the adjustment of lighting brightness in different applications, a thyristor dimmer was invented. By adjusting the conduction of the thyristor Angle, adjust the effective value of the input voltage to adjust the brightness of incandescent lamps, this kind of dimmer is not only widely used in public places, but also widely used in homes. [0003] With the development of the times, as a new light source, light-emitting diode (LED) is widely used because of its advantages of adjustable color, high luminous efficiency, low power consumption, high reliability and long life. There are many dimming methods for LED light sources, such as thyristo...

AI Technical Summary

Problems solved by technology

[0004] The existing linear drive thyristor LED dimming power supply circuit such as figure 1 As shown, the scheme has two current limiting units. Current limiting unit 1 is used to set a fixed discharge current to maintain the normal operation of the thyristor. Current limiting unit 2 is used to set a fixed maximum LED current. value, the defect of this scheme is that it cannot realize the requirement of LED without flicker

[0005] figure 2 As an improvement measure under the traditional scheme, it is necessary to add an additional current-limiting unit 3 to help the LED achieve the flicker-free requirement. Since the current-limiting unit 3 is a floating circuit module, an additional single chip is required to implement it, resulting in cost At the same time, the conduction angle of the thyristor dimmer will change under positive and negative voltages, which will still cause flicker

[0006] On this basis, the applicant proposed an adaptive adjustment control scheme to solve the ripple, and its circuit structure is as follows: image 3 As shown, but under this circuit structure, the thyristor dimmer loses the dimming function

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