App note from Holtek on smart battery chargers. Link here (PDF)
Battery chargers usually are products which transfer alternating currents to low voltage direct currents and which are widely applied in various rechargeable battery application fields. According to different applications, battery chargers can be divided into two types, namely digital chargers and power battery chargers. In not having an MCU for charge management, traditional charger applications fail to implement precise control of the battery charging curve, which will result in situations such as overcharging or charging to less than full capacity, situations which will affect battery life.
Holtek provides MCUs dedicated for power battery charger applications. In addition to resolving the problems of poor control of the charging curve, these MCU devices also include a battery charging management module, which can precisely control the charging voltage and current. The devices therefore reduce the need for the usually required external operational amplifier and TL431 components in traditional battery charging circuits. The charging voltage and current calibration parameters and profiles can be stored into the MCU’s internal EEPROM, thereby eliminating the need for traditional manual calibration, thus improving production efficiency.