AS3722 datasheet(56/199 Pages) AMSOSRAM

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Page 55

[v1-01] 2015-Sep-07

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AS3722 − Detailed Descriptions- System Functions

Power Off

To put the chip into ultralow power mode, write ‘1’ into

power_off. The chip stays in power off mode until he gets a

wakeup signal from either the ONKEY, LID or the AC_OK pin or

from the RTC. For more details see the start-up flowchart (see

Start-up Flow Chart). The bit power_off is automatically cleared

by this reset cycle. During power_off state all circuits are

shut-off except the Low Power LDO (V2_5) and the RTC

oscillator (if enabled). Thus the current consumption of AS3722

is reduced to less than 10μA. The digital part is supplied by

V2_5, all other circuits are turned off in this mode, including

references and oscillator. Except the reset control registers all

other registers are set to their default value after power-on.

Software Forced Reset

Writing ‘1’ into the register bit force_reset immediately starts a

reset cycle. The bit force_reset is automatically cleared by this

reset.

External Triggered Reset

If the pin XRES_IN is pulled from high to low by an external

source (e.g. microprocessor or button) a reset cycle is started

as well.

Over-Temperature Reset

The reset cycle can be started by over-temperature conditions.

(see chapter Supervisor)

Watchdog Reset

If the watchdog is armed (register bit wtdg_on = 1 and

wtdg_res_on= 1) and the timer expires it causes a reset. (see

chapter Watchdog).

AS3722 Datasheet(PDF) 56 Page - ams-OSRAM AG