Power bank is a device that stores power in a Li-Ion battery. It is being increasingly used as reserve charger for hand held/portable devices like mobile phones, tablets etc. A typical power bank has these components:
Charging circuit: it implements the complete charging logic for a Lithium Ion battery
Battery Protection circuit: it takes care of over charge and over temperature protections during charging and over discharge, over load and temperature protections during discharge.
Boost Converter: it steps up the 3V - 4.2V battery voltage to 5V.
Monitors output voltage and controls the pulse-width of gate drive of the MOSFET in boost converter.
Measures battery voltage and disables boost converter when battery voltage reaches the low voltage threshold.
Monitors the load current, turns off the boost converter when load is disconnected or when there is an overload.
Drives status LEDs to display battery level and charging or load status.
PSoC 1 provides a single-chip solution that integrates battery charging, battery protection and controller functions in a single chip; thus reducing BOM and PCB size. If required, an external hardware battery protection circuit can also be added for additional battery protection.