How do Power Bank work?
Update Time:2013-05-06
They have microprocessor controlled circuitry to control charge voltage & current to the 3.7V lithium batteries which are either cylindrical lithium ion or low profile Lithium polymer. There is also a step up DC-DC converter to boost the battery voltage up to the 5V output for the USB output. Protection circuits are there to prevent over charging, over discharging, over voltage, short circuit, over current and overheating.