Tuya Sandwich (PWM) Lighting Board

The Tuya Sandwich (PWM) lighting function board is a five-level dimming LED color lamp controller, which helps you quickly implement various smart hardware prototypes. It provides plenty of controlling interfaces to verify the functionality of the configured firmware and view the test results.

Product features

The Tuya Sandwich (PWM) lighting function board provides five dimming levels for the lighting function with warm white, cool white, RGB beads, and corresponding control chips. It has the following features:

The voltage inputted by hardware solution is boosted from 5V DC to 18V DC through DC-DC boost converter, which is used for the power supply of warm white, cool white, and RGB beads.
You can connect wireless modules such as Wi-Fi, Bluetooth, and Zigbee to control brightness, color temperature, and dazzling RGB by corresponding PWM signals.
DC-DC step-up circuit adopts the SY7208L boost control chip. The control of cool white and warm white light adopts the SLM211A DC-DC step-down PWM linear constant current dimmer control chip.
RGP control adopts the BP168CJ DC-DC step-down PWM linear constant current control chip.
Abundant peripheral PWM ports. It controls color temperature, brightness, and dazzling RGB through five PWM signals: PWMC, PWMW, PWMR, PWMG, PWMB.
You can view the peripheral ports through the silk screen on the board, and directly connect the control port to use it.

Introduction to key components

The Tuya Sandwich (PWM) lighting function board contains a DC-DC step-up chip, a CW two-level dimmer control chip, and an RGB control chip.

Components	Description
U1 (SY7208L)	High efficiency, 1 Mhz, 2A output step-up constant voltage controller, 3–25V input, and SOT23-6 package.
U2 (BP1638CJ)	Three-level dimmer LED linear constant current driver chip, which uses ESOP8 package.
U3, U4 (SLM211A)	The linear constant current driver chip, which supports PWM dimmer, SOT23-6 package, and 15 mA–350 mA output current.
D1–D6 (3535)	Three-in-one RGB beads which use 3535 package. Support the current of up to 30 mA.
D7–D15 C, W beads (2835)	3.0V–3.3V warm white 2700K and 3.0V–3.3V cool white 6500K, and 150 mA current.

Introduction to I/O ports

The pins used in the PWM hardware solution are shown as below:

I/O	Description
5V	5V power supply pin
GND	Power ground
3.3V	3.3V power supply pin
PWMC	Cool white PWM control signal, which is active high.
PWMW	Warm white PWM control signal, which is active high.
PWMR	RGB red light control signal, which is active high.
PWMG	RGB green light control signal, which is active high.
PWMB	RGB blue light control signal, which is active high.
I/O0	The button network configuration pin, which is active low.

Technical requirements

Power supply voltage: 3.3V and 5V
The average current of 3.3V power supply: 80 mA. It has an average output current of 200 mA and the peak value is 450 mA.
The maximum output current of 5V power supply: 200 mA.

Schematic diagram and PCB

Schematic diagram of Tuya Sandwich (PWM) lighting board: It has the following features:
PCB of Tuya Sandwich (PWM) lighting board:

Things to note

The development board needs to be used with the control board and the power supply board.
The power supply of the development board is 5V. It has a 3.3V port. 3.3V and 5V power supplies share the GND port.
The development board only supports five-level PWM control and does not support I2C.
Do not insert the I/O pin into the power port to prevent a chip breakdown.
The PWM signal control of ports on the development board corresponds to each other.