Tuya Sandwich DC-DC Power Board

The Tuya Sandwich DC power supply board is part of the Tuya Sandwich Evaluation Kit and is used to supply power to other related components.

The board has two input ports: DC 12V and DC 5V. When the DC 12V power supply takes effect, two SY8012B chips work together to provide DC 12V, DC 5V, and DC 3.3V power for other components. When the DC 5V power supply takes effect, one SY8012B chip works to provide DC 5V and DC 3.3V power for other components.

Features

The Tuya Sandwich DC power supply board adopts the standard physical size of Arduino, so you can directly stack the corresponding development boards on top for power supply.

• Flexible power input: DC 12V input through DC 005 port and DC 5V input through Micro USB port.
• Input over-voltage protection: Available for both 12V and 5V power input. 12V TVS diode and 5V TVS diode.
• Anti-reverse protection circuit: The 12V input port has an anti-reverse protection circuit composed of a fusible resistor and a TVS diode.
• Anti-reverse current: The SS14 diode prevents reverse current when the 5V power supply takes effect.
• BUCK circuit: Adopts the Silergy SY8012B chip which supplies the power of 5V, 1A and 3.3V, 1A. It uses the SOT23-6 package.
• Indicator light: Individual indicator lights are provided for 12V, 5V, and 3.3V power output.

Introduction to key components

The Tuya Sandwich DC power supply board contains 12V-5V and 5V-3.3V DC-DC step-down chips, a Micro USB port, and a 12V DC input port. It is shown as follows.

Introduction to I/O ports

The development board has a plenty of peripheral interfaces. The output pins of the DC power supply board are 12V, 5V, 3.3V, and GND. The definition of pins are as follows:

Technical requirements

• The power input supply voltage is 12V or 5V, and only one input voltage is allowed at one time.
• Refer to 12V power adapter for 12V power supply capacity.
• The maximum output current of 5V power supply is 1A.
• The maximum output current of 3.3V power supply is 1A.

Schematic diagram and PCB

• Schematic diagram of Tuya Sandwich DC power supply board:

  

• PCB of Tuya Sandwich DC power supply board:

  

Things to note

• Be careful when using the Micro USB 5V power supply, which can be easily damaged if the force applied is too big.
• The rated output current of the power working in both 5V and 3.3V mode is 1A. When it is overloaded, the output voltage will be lowered.
• When using the 5V voltage to input external power supply, be careful with the polarity to prevent damage to the power supply board.

Reference

• Demos
• Overview of the Tuya Sandwich Evaluation Kit