With the USB PD Decoy, a USB Type-C PD power adapter can be used as a power supply with the option of selecting different output voltages via DIP switches. It is based on the cheap and easy-to-use CH224K multi fast charging protocol power receiving chip.
The CH224K is a USB PD power receiving protocol chip, which integrates PD3.0/2.0, BC1.2 and other fast charging protocols, automatically detects VCONN and analog E-Mark chips, supports up to 100W power, and has built-in PD communication module. It also integrates output voltage detection internally to support overheating and overvoltage protection. It features:
- 4V to 22V input voltage
- PD3.0/2.0, BC1.2 and other fast charging protocols
- USB Type-C PD, positive and negative insertion detection and automatic switching
- E-Mark simulation, automatically detects VCONN, supports 100W power PD request
- requested voltage can be dynamically adjusted through a variety of methods
- high integration of single chip, simplified peripheral and low cost
- built-in over-voltage and over-temperature protection module
The output voltage can be selected via the DIP switches as follows:
| Output Voltage | SW1 | SW2 | SW3 |
|---|---|---|---|
| 5V | 0 | - | - |
| 9V | 1 | 1 | 1 |
| 12V | 1 | 1 | 0 |
| 15V | 1 | 0 | 0 |
| 20V | 1 | 0 | 1 |
The Power-Good LED lights up when the selected voltage has been successfully negotiated with the USB-C power adapter and is present at the output. The voltage can also be changed during operation.
A second PCB version implements an additional MOSFET for power path control, which only enables the voltage output after successful negotiation with the power supply.
