Breath light control circuit

Abstract

The invention provides a breath light control circuit, comprising a power supply, a first resistance and a second resistance which are connected in series, a first switching tube, a second switching tube, a third resistance, a fourth resistance and a controller, wherein one end of the first resistance is connected with the power supply, the collector of the first switching tube is connected with one end of the second resistance, and the emitter of the first switching tube is grounded; the base of the second switching tube is connected with a node between the first resistance and the second resistance, the emitter of the second switching tube is connected with the power supply; one end of the third resistance is connected with the collector of the second switching tube, the other end of the third resistance is connected with a breath light; one end of the fourth resistance is connected with the base of the first switching tube; and the controller is connected with the other end of the fourth resistance and is used for applying a PWM control signal to the first switching tube by virtue of the fourth resistance and gradually adjusting duty ratio of the PWM control signal according to a preset step size by taking a preset time as a period. The breath light control circuit provided by the invention has the advantages of simple design and low cost.

Description

technical field [0001] The invention relates to a non-portable lighting device or system, in particular to a control circuit for a breathing lamp. Background technique [0002] The breathing light device is applied to the terminal equipment. The brightness of the LED (Light Emitting Diode, light-emitting diode) in the device changes gradually from bright to dark under the control of the microcomputer, as if breathing. It can provide visual prompts on the terminal equipment and play a role. Very good visual decoration effect, has been widely used in various fields such as home appliances, mobile phones, computers, automobiles, etc. [0003] The breathing light products currently on the market usually use the following two methods to control LED lights: [0004] (1) Control the working of the breathing light through PWM (Pulse Width Modulation, Pulse Width Modulation) of high frequency (above 10KHz). The disadvantage of this method is that the main chip needed is relatively a...

AI Technical Summary

Problems solved by technology

[0004] (1) Control the working of the breathing light through PWM (Pulse Width Modulation, Pulse Width Modulation) of high frequency (above 10KHz). The disadvantage of this method is that the main chip that needs to be used is relatively advanced and the cost is relatively high;

[0005] (2) Separately increase the chip to control the current output to control the breathing light. The disadvantage of this method is that more components need to be added, which will also increase the production cost

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