HCS12 based embedded PWM Controller for battery charger application

Abstract

With present wireless communication revolution, possession of mobile phones, MP3 walkmans, Ipods, Ipadsthe convenience of quick and easy communication, information storage and search, the situation has also brought to concern certain issues regarding their operation.
Every cell phone comes with a rechargeable battery and battery charger. The devices like PDA, MP3 Walkman, and digital cameras all require batteries to operate, adding to the importance of rechargeable batteries.
The cellphone batteries get damaged due to overcharge and subsequent signal deterioration due to absence of charge. Overcharging the battery will lead to lessening the battery life.
Li-ion and Ni-Cd batteries are well suited to portable devices like cell phones, walkmans, by virtue of their small size and weight. However, life cycles of the batteries are easily affected due to overcharging and undercharging.The reason being that overcharging damages the physical components of the battery. On the other hand undercharging reduces the energy capacity of a battery.
Thus,arises the need for an intelligent voltage and current controlled PWM microcontroller based battery charger to prevent the overcharging. The battery charger application will include an electromagnetic interference filter,bridge rectifier,transformer,switching that operates with the help of a microcontroller unit of a PWM controller.A current detection block,voltage detection block and a temperature detection block are feedback through differential amplifiers into the Analog to Digital conversion unit of the microcontroller. Microcontroller facilitates advanced user interface.
The application aims at efficient battery performance, safety and cost.