The intelligent LED bulb light Bluetooth solution can be divided into four modules: AC-DC constant voltage module, DC-DC constant current module (the number of which is determined by the color matching effect), LED color changing module and Bluetooth control module.
1 smart LED bulb light Bluetooth program principle
As shown in the figure below, the intelligent LED bulb Bluetooth solution can be divided into four modules: AC-DC constant voltage module, DC-DC constant current module (the number of which is determined by the color effect), LED color change module and Bluetooth control Module. The following is a detailed description of the functions of each module:
Principle frame
1.1 AC-DC constant voltage module
If the AC-DC constant voltage module is combined with the DC-DC constant current module, then it is a multi-channel constant current output LED switching power supply, and from the AC-DC constant voltage module, it is a constant voltage output switch. power supply. Because it involves the need to control the different states of the multi-output to achieve the purpose of color temperature adjustment, the integrated AC-DC constant current switching power supply scheme is not directly used here, if the AC-DC multi-output chip is directly used for design. It will encounter similar problems such as mutual interference between each output, and each channel's dimming signal will interfere with each other. Therefore, it is still a mode that uses AC-DC constant voltage and DC-DC to achieve constant current. This module mainly realizes the function of converting AC mains into DC constant voltage level to power the rear DC-DC module and Bluetooth control module.
1.2 DC-DC constant current module
The DC-DC constant current module is driven by the constant voltage level output from the AC-DC constant voltage module, and realizes the function of outputting constant current through the switch of the built-in Mos tube. At the same time, the analog dimming foot on the DC-DC chip will adjust the output constant current according to the square wave signal given by the Bluetooth control module to realize the smart bulb changing brightness and changing the color temperature personalized function. The number of channels of the DC-DC constant current module is determined by the effect of the output change desired by the user. If the user only needs to adjust the warm light to the cool white light, then only two DC-DC modules are needed. If the customer needs to implement more colorful dimming solutions, then at least four DC-DC modules are needed.
1.3 output buck module
Since the input voltage required by the Bluetooth module is smaller than the output voltage of the back-end LED and the input voltage is required to be stable and the ripple factor is small, an output step-down module is required between the Bluetooth module and the AC-DC module. To achieve the purpose of buck and voltage regulation, if a simple RC mode is used, there may be a large instantaneous current that may damage the Bluetooth chip. At present, there is a product (LDO) in which a voltage stabilizing circuit is integrated in a chip, and the use of such a chip will reduce the size of the entire design scheme, and also make the PCB board layout simple.
1.4 LED color change module
This module is mainly based on the output lighting function. For example, the customer mentioned in 1.2 will have some choice of dimming scheme. If two-way DC-DC constant current scheme is adopted, the LED color changing module only needs to stick 3000K on the aluminum substrate. 6500K two kinds of lamp beads; if four-way DC-DC constant current scheme is adopted, the LED color changing module needs to be mounted with four LEDs of red, green, blue and white.
1.5 Bluetooth Control Module
This module receives the operation information on the mobile APP through the antenna and outputs the PWM signal to the DC-DC constant current module to adjust the current of 4 red, green, blue and white LEDs or 2 to 3000K, 6500K color temperature LED current. Make adjustments so that the LED color change module outputs the light of the color desired by the user.
5 Conclusion
The emergence of Bluetooth 4.0 provides a promising future for miniaturization of smart homes. Its low power consumption, low cost, small size and high transmission rate are in line with the development direction of miniaturization, while indoor use and control are just right. To make up for the shortcomings of its short transmission distance, in summary, we have reason to believe that Bluetooth 4.0 will have a longer-term development in the smart home market.
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