Start • Design Requirements • System Architecture • External Charging Unit • Internal Charging Unit • Charging Coils • Charging Data • Power Up • Sources and PDF

In this article, we’ll describe a portable power supply capable of providing 100-mA, 3.3-V continuous power to an embedded application. The batteries in the power supply are inductively charged so no physical connections to the charging apparatus from the portable application need to be made.

Our design is based on a Linear Technology LTC1325 microprocessor-controlled battery management system. The supply consists of two battery packs. One pack supplies power to the embedded application while the other pack is charged. When the pack supplying power to the application is discharged, the two packs are switched. The second pack then supplies power while the first pack is recharged. The LTC1325 monitors the battery packs’ temperature and voltage when the system is operating. You may change the system’s parameters to optimize performance depending on the type of batteries being used (NiMH, NiCd, or Li-Ion).