Hardware Overview

The BC100 consists of two main parts: the battery charging circuits and circuits related to the ATmega644 board controller. The battery charger circuits can be used without interaction with the board controller.

The charger circuits has two AVR® sockets, one for the ATtiny261/461/861 and on for ATtiny25/45/85. From factory the kit is delivered with both an ATtiny861 and an ATtiny85. Both of these can control the buck-converts on the board, but not at the same time.

The board has three buck-converters: These three have different voltage and current rating, and can be used depending on the requirements for charging voltage and current.

The buck-converter outputs are connected to either of the two battery terminals through relays, which are controlled by the device in the ATtinyx81 socket. This offers the possibility to use two battery packs with a single charger. This makes it possible to e.g. replace a depleted battery while running the application from the other battery.

The schematics, bill of material and layout can be found as separate PDF documents in the ZIP file distributed with this application note.

Figure 1. Top view - overview of the BC100