The average inductance current can be calculated by input voltage and output voltage to use in PI regulator.
通过采样输入输出电压以获取电感的平均电流，从而代替了实际的采样电流，以进行PI调节。
2
VCC power | VF LED voltageregulator, driving voltage, IF forward current.
VCC为电源|稳压器电压，VF为LED驱动电压，IF为顺向电流。
3
The schematics includes four parts: bandgap reference voltage and reference current, 2.7V and 1.8V regulator, over-load protection , Low Battery Detection (LBD) .