Mini PoE Priority 12V Power Distribution Board

Client project Documented engineering work

A compact 30×30 mm 2-layer power distribution board designed to accept either a 12–15V DC input or PoE-based input, automatically prioritize PoE when both sources are connected, and provide three protected 12V outputs through JST connectors.

PROJECT GALLERY

Project Gallery

OVERVIEW

Overview

This project is a compact power input and distribution PCB designed for embedded electronics, IoT devices, camera systems, control modules, automation hardware, and small electronic systems that require a reliable 12V supply from more than one source.

The board supports two power input paths: a direct 12–15V DC input and a PoE-based input. When both power sources are connected at the same time, the onboard power-path circuit automatically gives priority to the PoE input. This makes the board suitable for systems where Ethernet/PoE should be the preferred operating source, while the auxiliary 12–15V input can act as a secondary or backup supply.

The board distributes the selected 12V rail to three JST output connectors. Each output path is protected and current-limited, with a default current limit of 2A per output. The output current limit can also be adjusted based on the final application requirement.

KEY FEATURES

Key Features

Dual input support through 12–15V DC input and PoE input

Automatic input source selection with PoE priority

3× protected 12V JST output connectors

Default 2A current limit per output, adjustable based on client requirement

Hot-swap support for safer load connection during operation

Input protection for over-voltage, under-voltage, ESD, over-temperature, and over-current events

Output protection for over-voltage, under-voltage, ESD, over-temperature, over-current, and short-circuit conditions

Compact 30×30 mm PCB size for space-limited embedded products

Production-friendly 2-layer PCB design

Verified working result confirmed through client testing

TECHNICAL SPECIFICATIONS

Board Function	PoE-priority 12V power distribution board
Input Sources	12–15V DC input and PoE input
Priority Logic	PoE is automatically prioritized when both inputs are connected
Active Rail	Protected 12V distribution rail
Target Use	IoT devices, camera systems, embedded controllers, and compact automation hardware

Output Channels	3× protected 12V outputs
Connector Type	JST output connectors
Current Limit	2A default per output
Current Adjustment	Output current limit can be adjusted based on application requirements
Hot-Swap Support	Supported for safer load connection and disconnection

Input Protection	Over-voltage, under-voltage, ESD, over-current, and over-temperature protection
Output Protection	Over-voltage, under-voltage, ESD, over-current, and over-temperature protection
Short-Circuit Behavior	Current-limited output protection behavior
Power-Path Safety	Automatic source selection prevents unsafe dual-input behavior
Reliability Focus	Designed for real-world cable connection, load changes, and embedded system use

PCB Size	30 × 30 mm
Layer Count	2-layer PCB
Copper Weight	1 oz copper
Board Type	Compact embedded power distribution PCB
Layout Focus	Small footprint, protected power routing, JST output access, and production-friendly assembly

TEST RESULTS

Test Results

Test Area	Validation Method	Status	Result / Notes
12–15V DC input validation	Power the board through the auxiliary 12–15V DC input and verify stable 12V output distribution.	Verified	The board operated correctly from the direct 12–15V input path during testing.
PoE input validation	Power the board through the PoE input path and verify that the selected power rail is distributed to the 12V outputs.	Verified	The PoE input path was tested and confirmed functional.
Input priority validation	Connect both the 12–15V DC input and PoE input at the same time, then verify which source powers the board.	Verified	When both inputs were connected, the board correctly prioritized the PoE input.
12V output rail validation	Verify the regulated/protected 12V output rail across the available JST output connectors.	Verified	The 12V output rail was verified across the board output section.
JST output connector check	Check all three JST output connectors for correct power delivery and output availability.	Verified	All three 12V JST output connectors were tested and confirmed working.
Current limit behavior check	Review and test output current-limited behavior according to the default 2A output configuration.	Verified	Each output is designed with a default 2A current limit, which can be adjusted based on the final product requirement.
Protection behavior validation	Review protection behavior for abnormal input/output conditions, including over-current, voltage-related events, and thermal protection response.	Verified	Input and output protection behavior was validated during project testing.
Hot-swap support check	Connect and disconnect output loads during operation to verify safer load connection behavior.	Verified	The board supports hot-swap load connection for practical embedded system use.
Client functional confirmation	Final board behavior reviewed and confirmed after client-side testing.	Verified	The client confirmed that the board worked as expected after testing.

DELIVERABLES

Deliverables

Schematic design

PCB layout

Component selection

Power-path design

PoE and auxiliary input planning

Input priority circuit design

Protection circuit design

JST connector output planning

Current-limited output design

PCB manufacturing files

Gerber files

Bill of Materials

Pick-and-place files

Assembly notes

Testing support

Revision-ready documentation

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