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Application Report
SLUA687–July 2013
Using bq2425x’s DPM Feature for Solar Panel
Applications
TaharAllag/JamesSmith
ABSTRACT
After installation and maintenance expenses, harvesting the sun’s energy through the use of solar cells
panel is 100% free and clean energy. Despite the superb performance of this technology, its characteristic
limitation tenders them difficult to use in some applications, especially in portable power applications. This
application note explores how to overcome its characteristic limitation by using the VIN_DPM feature of
the bq2425x single battery charger.
Contents
1 Introduction .................................................................................................................. 1
2 Solar Cell Panel ............................................................................................................. 1
2.1 Solar Cell Panel Overview ........................................................................................ 1
2.2 Understanding Maximum Power Point of a Solar Cell Panel ................................................ 2
3 Input Voltage Dynamic Power Management ............................................................................ 2
3.1 bq2425x Input Voltage-Based DPM ............................................................................. 2
3.2 Adjusting the VIN_DPM of the bq2425x ........................................................................ 3
4 Input Voltage DPM for Solar Panel Applications ........................................................................ 4
5 Solar Cell VIN_DPM Design Example and Test Result ................................................................ 5
List of Figures
1 Solar Panel’s V-I Curve and Output Power Curve...................................................................... 2
2 bq2425x Typical Application Circuit ...................................................................................... 3
3 Controlling Solar Cell Current Using VIN_DPM Feature of bq2425x Charger...................................... 4
4 VIN_DPM on Solar Panel Test Result ................................................................................... 5
List of Tables
1 Introduction
The bq2425x is a highly-integrated single-cell Li-ion battery charger device targeted for space-limited,
portable applications with high-capacity batteries. The charger has a single input that operates from either
a USB port or AC wall adapter. A solar panel can also be used as an input power supply as long as it
provides the charger with the adequate power and input voltage needed to operate.
2 Solar Cell Panel
2.1 Solar Cell Panel Overview
A solar cell converts solar energy (light) into electrical energy through crystalline or amorphous silicon
photovoltaic panels. There are many advantages for this renewal energy source; however its application is
not straight forward.
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SLUA687–July 2013 Using bq2425x’s DPM Feature for Solar Panel Applications
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