LED Controller

 
I. Product Introduction: This Tuya LED desktop lamp uses a Tuya Bluetooth module for LED light control. It features one RGB three-color light control channel, one warm light LED channel, and one cool light LED channel. Bluetooth control and stepless dimming are achieved via the Tuya Smart Life APP.
II. Board Functions: 1. Selectable Power Supply: The control board has an AC-DC (12V) power module, which can be soldered. If this module is not needed, a 12V power input can be used directly. 2. One RGB driver with three-color lighting effects, adjustable colors, and ambient lighting. 3. One warm light LED dimming driver for general lighting, with stepless dimming via the APP. 4. One cool light LED dimming driver with a 0.5W LED bead, with stepless dimming via the APP. 5. Button for turning on the light, or touch switch for selecting lighting effects. 6. 12V power supply. (An AC-DC module can be selected, using 220V power supply. This project uses a 12V DC external power supply.)
III. Rendering of the LED board + control board:
1. 3D front view of the LED board PCB
; 2. Color silkscreen image of the LED control board PCB;
3. Actual photo.
 
 
IV. Circuit description and usage introduction: 1. This project consists of an LED board and an LED control board. The LED board is made of aluminum substrate for easy heat dissipation of the LED beads. The board has 8 3535 RGB LED beads; 1 0.5W high-power LED bead (3.2V cold light LED bead); and 12 warm white 2835 LED beads in series and 3 in parallel, totaling 36 beads.
2. The RGB LED power supply uses a SY7208 to boost the voltage, then powers the 8 strings of RGB LEDs. (Note that some SY7208 chips have different specifications; pay attention to pin 6 of the chip. Some chips require a connection, possibly a power supply pin. During project debugging, the DC power boost was consistently faulty; after powering pin 6 of the chip, the boost was normal.) The RGB constant current control chip is the BP1638CJ, a three-channel dimmable LED linear constant current driver chip with a built-in 40V/200mA MOSFET. By adjusting the duty cycle of the three input PWM signals, it adjusts the current of the corresponding LED light source to achieve dimming. It supports PWM dimming signals and can be used with common dimming modules to implement dimming functions. For protection, it has an over-temperature regulation function; when the LED current is too high and the chip temperature is too high, it will reduce the output current.
3. The project's warm light uses the SY7301 chip, an LED constant current driver chip. The SY7301A features a boost DC/DC converter to provide precise constant current for driving the LEDs. Operating at a fixed switching frequency of 1MHz, it allows the use of small-value external ceramic capacitors and inductors. The series-connected LEDs are driven by a regulated current set by an external resistor. The SY7301A is ideal for driving up to 10 white LEDs in series or up to 40V. Therefore, 12 series-3 parallel 3.2V warm light LEDs were used.
 
4. The project's cool light uses the PT4115 constant current LED driver. The PT4115's operating voltage can vary from 5V to 24V, and the output current can be adjusted within this range. Output current: The PT4115's maximum output current can reach 1.2A, but can be further adjusted via the external ADJ pin to achieve a lower output current than the set value. It is mainly used for 1W or 3W high-power LEDs. Therefore, the project uses a single 3.2V dual-core 1W LED for the cool light.
5. The board also has a reserved power supply module, which uses an existing AC-DC module with a 12V output to power the lamp. An external power supply module is also possible; the board has a reserved 12V power supply pad for soldering out an external DC power supply. Due to space constraints caused by a design flaw in the casing, an external power supply was used in this project. Note that this is the first time designing a casing structure, there are some minor structural issues, but these are acceptable and not 100% perfect, and do not affect usability.
6. 3D casing design:
7. The lamp's top cover uses an acrylic cover plate, also printed by JLCPCB. Below are the acrylic printing specifications. The printed pattern is also included in the PCB project file and is open-source on the project platform. Note that the acrylic in the file does not have adhesive backing because I used acrylic glue. If you need to make it with adhesive backing, you can follow the instructions. Note that the file does not include a cutout for adhesive backing; the file needs to be modified before production.
V. Product testing video