© 2006 Semtech Corp.

POWER MANAGEMENT

SC614

United States Patent No. 6,504,422

www.semtech.com

10

State Diagrams

When the SC614 is first enabled, it starts up in Sleep Mode, with the registers at their reset values and the charge

pump off. The bandgap reference will be operating, the input voltage will be monitored for UVLO and the serial

interface will be monitored for any activity. This is the lowest power state for the device where it can be

communicated with. In order to activate the charge pump it is necessary to clear the Sleep bit to 0 to enter Run

Mode. When in Run Mode the charge pump is activated in 1x mode with VOUT = 1.5V, and all of the optional

functions of the device may be accessed.

Shutdown

Sleep Mode

( SLEEP = 1 )

Power Off

VIN high ,

EN

low

EN

= High

VIN , EN high

Run Mode

( SLEEP = 0)

SLEEP = 0

Lowest Power State. All internal

functions powered down

Bandgap up, UVLO and serial

interface monitoring active only

Bandgap up, UVLO and serial

interface monitoring active,

charge pump running with

VOUT = 1.5V

Start-Up