POE or Power Over Ethernet is a technology that lets electrical power to be transmitted along with data over standard Ethernet cables. This eliminates the need for separate power cables and power supplies for networked devices, making it a convenient and cost-effective solution for powering and connecting devices in networked environments. POE is primarily used to power devices such as IP phones, wireless access points, security cameras and IOT Devices that are typically located in areas where it is difficult or expensive to install electrical outlets. With PoE, these devices can be powered through the same Ethernet cable that is used for data communication, making installation and maintenance much simpler. There are two main types of PoE: PoE and PoE+. Standard PoE delivers up to 15.4 watts of power, while PoE+ delivers up to 30 watts of power. This increased power delivery allows PoE+ to power devices with higher power requirements, such as pan-tilt-zoom (PTZ) cameras and video conferencing equipment.

To use PoE, both the network switch and the device being powered must support PoE. PoE-enabled switches automatically detect and provide power to PoE-enabled devices, while non-PoE devices will simply receive data and not power.

PoE is a convenient and cost-effective solution for powering and connecting networked devices, particularly in areas where electrical outlets are difficult or expensive to install. Its increasing popularity and widespread adoption make it an important technology for network engineers and IT professionals to understand and implement.

About this project:

In this project, we’re going to use a PoE (Power over Ethernet) as the main power source to our USB hub to ease power-ups of our IOT Devices, such as Raspberry Pi, PICO, ESP32, or your DuinoCoin Miner. The main core of this project is a ROHM BD9G341AEFJ regulator to drop our POE voltage to 5V. For more technical details, please refer to the datasheet below.


The BD9G341AEFJ as a DC/DC converter. This device is designed to convert a high voltage input to a lower voltage output, with high efficiency and a compact form factor.

Specifications of the BD9G341AEFJ:

  • Input voltage range > 12V to 76V
  • Output voltage range > 3.3V to 60V
  • Maximum output current > 3A
  • Switching frequency > 300kHz to 2.2MHz
  • Efficiency > up to 96%
  • Protection features > Overcurrent protection, thermal shutdown, input Undervoltage lockout, and output overvoltage protection

BD9G341AEFJ is a high-performance DC/DC converter that can be used in a variety of applications. Its small size and high efficiency make it well-suited for use in space-constrained designs. The device can operate with input voltages ranging from 12V to 76V, which makes it useful for a wide range of industrial, automotive, and consumer applications.

The output voltage of the BD9G341AEFJ can be adjusted using an external resistor divider, which allows it to be easily customized for specific applications. The device also features a wide range of protection features, including overcurrent protection, thermal shutdown, input undervoltage lockout, and output overvoltage protection, which help ensure that the device operates reliably under a variety of conditions.

Examples of how the BD9G341AEFJ can use:

  1. Power supply for LED lighting
    • LED Lighting: The BD9G341AEFJ can be used to power LED lighting systems in a variety of applications, including streetlights, commercial lighting, and architectural lighting. The device’s high efficiency and adjustable output voltage make it well-suited for driving LED strings of different lengths and configurations.
  2. Power supply for industrial equipment
    • Industrial Equipment: The BD9G341AEFJ can be used to power a variety of industrial equipment, including motor drives, machine vision systems, and robotics. The device’s compact size and high efficiency make it well-suited for use in space-constrained environments.
  3. Power supply for automotive systems
    • Automotive Systems: The BD9G341AEFJ can be used to power a variety of automotive systems, including infotainment systems, lighting systems, and safety systems. The device’s wide input voltage range and robust protection features make it well-suited for use in the harsh environments encountered in automotive applications.
  4. Power supply for consumer electronics such as TVs and set-top boxes
    • Consumer Electronics: The BD9G341AEFJ can be used to power a variety of consumer electronics, including set-top boxes, gaming consoles, and home automation systems. The device’s high efficiency and compact size make it well-suited for use in energy-efficient designs.

Overall, This device is a versatile and reliable DC/DC converter that can be used in a wide range of applications. Its high efficiency, compact size, and robust protection features make it a popular choice for DC/DC converter.

Requirements & Parts List

Part Value Device Package
C2,C8 0.1uF 0603CAPS 0603CAPS
F1,F2,F3,F4,F5 ASMD1812-125-FUSE ASMD1812-125-FUSE FUSC4632X130N
F6,F7,F8,F9,F10 ASMD1812-125-FUSE ASMD1812-125-FUSE FUSC4632X130N
IC2 BD9G341AEFJ BD9G341AEFJ SOIC127P600X100-9N
J4 RJ45-8N-S RJ45-8N-S TE_RJ45-8N-S
L1 33uH 4.5A 7447709330 WE-PD_1260/1245/1280/121054
R5 4.7k R0603 R0603
R9 110K 0603RES 0603RES
R10 27K 0603RES 0603RES
R11 3K3 0603RES 0603RES
R12 47K 0603RES 0603RES
R13 8K2 0603RES 0603RES
R14 2K 0603RES 0603RES
USB1-USB10 USB1130-15-A_REVA USB1130-15-A_REVA GCT_USB1130-15-A_REVA


Gerber / Milling Files :

Downloads :

14CORE POE (Power Over Ethernet) to USB-A 5V Power Hub / Server Rack Mountable for RPI/ESP8266/ESP32
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