Pi-Connect Lite V2 (PiPowerNew)

A Raspberry Pi HAT power supply board designed to power a Raspberry Pi from a wide-range DC input (7V–30V), with a push-button on/off, 2x Dronecode-compatible telemetry ports, and power protection (ESD, overcurrent, reverse voltage).

Designed by Rpanion Electronics.

User documentation is here

Design

The design is based on the AP64501SP-13 DC-DC switching regulator. Based on the component selection, is capable of outputting 5.16V at 3.5A.

To ensure no power backflow from the Raspberry Pi, a TSM2323 FET is used as an ideal diode between the output of the switching regulator and 40-pin header. This does reduce the output power slightly to between 5.12 and 5.05V, depending on current (see ./Functional Testing/Voltage Drop.ods)

An STM6601 Power Manangement IC is used to control the on-off state of the power supply. This includes a shutdown command from the Raspberry Pi or via the power button. A small 3.3V LDO is used to power the STM6601. This allows a safe shutdown of the Raspberry Pi, without risking SD card corruption.

For reverse voltage protection (up to 30V) DMP4013LFG-7 FET is used as an ideal diode between the XT30 input and the rest of the board. A pair of ESD diodes also protect against any voltage spikes greater than 33V.

Two 6-pin JST-GH connectors (Dronecode Telemetry compliance) are used for standardised connections to common ArduPilot and PX4 flight controller. Neither connector is powered. The primary connector maps to /dev/ttyAMA0 or /dev/serial0, depending on RPi OS and version), also known as UART0 on the 40-pin header. The secondary connector maps to /dev/ttyAMAx, where x can be 0-4 depending on system configuration) and is mapped to UART4 for the Raspberry Pi 4 or 5 models (including the RTS/CTS lines).

A small EEPROM is connected to ID_SC and ID_SD to identify the board, as per the Raspberry PI HAT specifications.

GPIO Usage

GPIO	Direction	Function
GPIO 4	Input	PI_OFF – trigger GPIO shutdown (active LOW starts shutdown sequence)
GPIO 26	Output	PWR_OFF – driven HIGH by Pi when shutdown sequence is complete
GPIO 14	Output	Pi Serial Tx
GPIO 15	Input	Pi Serial Rx
GPIO10	Output	UART4 CTS (Pi4/5 only)
GPIO9	Input	UART4 RX (Pi4/5 only)
GPIO11	Input	UART4 RTS (Pi4/5 only)
GPIO8	Output	UART4 TX (Pi4/5 only)
ID_SC	Output	EEPROM
ID_SD	N/A	EEPROM

Repository Contents

PiPowerNew.kicad_sch       - Schematic
PiPowerNew.kicad_pcb       - PCB layout
PiPowerNew.kicad_pro       - KiCad project file
Design/                    - Inductor calculations
EEPROM/                    - HAT EEPROM firmware and flashing script
Manufacture/               - Gerber files, BOM, component placement, test procedure
Compliance/                - HAT/HAT+ and EN50581 compliance documentation
Functional Testing/        - EMI test results, power efficiency, voltage drop data

Programming the HAT EEPROM

The EEPROM/ directory contains binary images and a helper script to flash the HAT ID EEPROM on the board. Requirements:

• i2c-tools package installed
• I2C enabled on the Raspberry Pi
• dtparam=i2c0=on added to /boot/config.txt

Steps:

# Clone the Raspberry Pi HAT utilities
git clone https://github.com/raspberrypi/hats.git
# Run the flash script from the EEPROM directory
cd EEPROM/
bash writeEEPROM.sh

The script builds the eepmake/eepflash tools and writes Pi-Connect-Lite-v2.1.bin to the board's EEPROM at I2C address 0x50.

To verify after flashing:

ls /proc/device-tree/hat/

Manufacturing

The Manufacture/ directory contains all files required for PCB manufacturing, based on a KiCAD export:

• gerber.zip – PCB fabrication files
• position.zip – Component placement files for pick-and-place assembly
• BoM.xlsx – Bill of Materials
• Pi-Connect V2.1 Test Procedure.docx – Functional test procedure

Manufacturing your own boards

Any users wishing to manufacture their own boards must not include any "Rpanion Electronics" identifiers on the PCB.

Likewise, the EEPROM must not use the Rpanion Electronics vendor string or product UUID.

Design Tools

The PCB is designed in KiCad (v8+).

License

See repository for license details.