A laptop battery is charged by an external power. Which is usually output dc voltage and provides power to system and charge battery simultaneously. When battery fully charged continue supply to the system through the adaptor and cut battery charging. Every laptop has its type of configured battery charging circuit. The charging process is managed by multi-controllers like:
• Charging ic
• KBC I/O controller (for battery temperature, level, enable and adaptor detection)
• Battery internal ROM chip or external ROM u28 (battery must be connected)
First of all system supply B+(main supply source) is available for system startup
Note: for more on B+ Supply Read Article
