To achieve fast charging function on the mobile phone needs to meet three indispensable elements. Charger, battery, charge IC. The charger needs to meet sufficient output current and output voltage, because the charger's wiring has a large parasitic resistance, to achieve a large charging current, the charger's on-load output voltage needs to be high. There are two ways to solve the battery life, one is to use a large battery directly, the other is to use a fast charging technology.