INTRODUCTION

　　For a variety of reasons， it is desirable to charge batteries as rapidly as possible. At the same time， overcharging must be limited to prolong battery life. Such limitation of overcharging depends on factors such as the choice of charge termination technique and the use of multi-rate/ multi-stage charging schemes. The majority of battery charger ICs available today lock the user into one fixed charging regimen， with at best a limited number of customization options to suit a variety of application needs or battery types. The LTC?1325 addresses these shortcomings by providing the user with all the functional blocks needed to implement a simple but highly flexible battery charger （see Figure 1） which not only addresses the issue of charging batteries but also those of battery conditioning and capacity monitoring. A microprocessor interacts with the LTC1325 through a serial interface to control the operation of its functional blocks， allowing software to expand the scope and flexibility of the charger circuit.

　　This Application Note was written with the following objectives in mind ：

　　? Provide users with an insight into the architecture and operation of the LTC1325.

　　? Outline basic techniques for charging various battery types.

　　? Present a variety of useful， tried and tested charging circuits.

　　? Give an overview of the most common battery types and their characteristics.

　　? Clarify specialized and application-specific terminology. Definitions are provided in the text， as well as in Appendix C