After looking at some details related to the practical aspects of the charging algorithm, how should charging system be implemented? Like any power supply design problem, the “volts and amps” is the starting point. In this case, this means the user wants a charger with 4.2V at either a few hundred mA or possibly up to a few Amps. Again, like any power supply design problem, using a linear regulator is a consideration if the system is operating at relatively low current and needs a simple, low cost solution. However, if a higher current is passed, a switch mode charger may be desired to maximize efficiency and minimize heat. A typical threshold where a switch-mode charger would be chosen is around 1A of charging current required.