This is a introduction for flashlight chip LM3642

[Scope]
- one channel for one LED
- Two silicon revision
	* LM3642
	* LM3642LT (Half torch current)


[Hardware Interface]
- I2C
	* For general control
	* Slave address 0x63


[Limit]
- Torch Mode
	* Min currnet: 48.4 mA (24 mA for LM3642LT)
	* Max current: 375 mA (187.5 mA for LM3642LT)

- Strobe Mode
	* Min currnet: 93.75 mA
	* Max current: 1500 mA
	* Min protected timeout: 100 ms
	* Max protected timeout: 800 ms