Tiny Solar Power Supply

Tiny Solar Power Supply

A compact solar-powered DC-DC boost converter designed in KiCad 10, based on the Tiny Solar Supply project published by Elektor Magazine. This project converts the voltage from a single 1.2 V Ni-MH rechargeable battery, charged by a small solar panel, into a regulated 3.3 V DC output suitable for powering low-power embedded systems and IoT devices.

The objective of this project was to gain practical experience in PCB design, schematic capture, component placement, routing, design verification, and version control using Git and GitHub.

Project Overview

The Tiny Solar Supply is built around the AP3015AKTR-G1 micropower boost converter, capable of operating from input voltages as low as 1 V while providing a regulated 3.3 V output. The circuit automatically enables or disables the boost converter depending on the availability of solar power, maximizing battery life and improving energy efficiency.

This implementation includes the complete KiCad project, PCB layout, Gerber files, and project documentation.

Key Features

• Solar-powered battery charging
• Regulated 3.3 V output
• AP3015AKTR-G1 low-voltage boost converter
• Automatic shutdown during battery charging
• Compact single-board PCB layout
• On/Off control header
• Designed using KiCad 10
• Version controlled with Git and GitHub

Hardware Specifications

Circuit Description

The solar panel charges a single-cell Ni-MH battery through an SS14 Schottky diode (D2). While the solar panel is producing power, it pulls the gate of the 2N7002 MOSFET (Q1) high, keeping the AP3015AKTR-G1 boost converter in shutdown mode and preventing unnecessary battery discharge.

When sunlight is no longer available, the solar panel voltage drops, turning the MOSFET off. This pulls the shutdown pin low and enables the boost converter, which steps the battery voltage up to a regulated 3.3 V output for powering external electronics. The output voltage is set by the R1/R2 feedback resistor network:

VOUT = 1.23 × (1 + R1 / R2)

Components Used

Design Workflow

Both schematic and PCB layout were built and version-controlled stage by stage — full history is in the commit log:

• Schematic: setup → place symbols → arrange/annotate/assign footprints → wire → net labels & power flags → ERC (clean) → title block & comments
• PCB layout: setup → board outline & mounting holes → place footprints → route traces & ground plane → silkscreen → DRC (clean) → Gerber export

Learning Outcomes

This project provided hands-on experience in:

• PCB design using KiCad
• DC-DC boost converter design concepts
• Solar-powered embedded systems
• Power management circuits
• PCB routing and layout optimization
• Design Rule Check (DRC)
• Gerber generation for PCB manufacturing
• Hardware project documentation
• Git and GitHub for version control

Acknowledgements

This project is based on the Tiny Solar Supply design by Clemens Valens, originally published in Elektor Circuit Special 2023. The original article describes a compact solar-powered boost converter using the AP3015/AP3015A DC-DC converter. This repository contains an independent KiCad implementation, PCB layout, project organization, and documentation created for learning and educational purposes.

License

This repository is shared for educational purposes.

The original circuit design is credited to Elektor Magazine and Clemens Valens. Please refer to the original publication for the source design and associated rights.