AN2390 Datasheet, PDF (1/42 Pages) STMicroelectronics – A flexible universal battery charger

AN2390
Application note
A flexible universal battery charger
Introduction
In everyday life, more and more portable electronic appliances, such as mobile phones, are
powered by re-chargeable batteries so the demand for battery chargers for charging these
batteries is increasing all the time.
This Application Note describes a cost-effective way to implement an intelligent battery
charger for charging Li-ion and NiMH batteries as shown in Figure 1.
Figure 1. Universal battery charger evaluation board (STEVAL-ISB002V1)
It is based on a evaluation board built around the ST72324L microcontroller with a demo
application code.
While the evaluation board described in this Application note is intended to be used for
single cell Li-ion battery or 2 cell NiMH batteries you can customize this charger for a wide
range of batteries because of the flexibility of the MCU and of the buck boost converter. The
ST72324L MCU was selected for its main features, an embedded 10-bit A/D converter (to
efficiently measure voltage, current and temperature), 16-bit timer (to generate PWM
signals), main clock controller (to generate a time base signal) and 8 Kbytes of program
memory which is more than enough to hold the algorithm for various battery chemistries.
You can choose any other MCU that has similar capability. An LED is also used to indicate
the charge status.
August 2007
Rev 1
1/42
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