L9961 datasheet(9/63 Pages) STMICROELECTRONICS

9 / 63 page

Functional description

3.1

Device funcional states

L9961 can operate in 3 different states when battery is applied: SHIPMENT - DEEP SLEEP, STANDBY or

NORMAL.

Figure 2. Device FSM

GADG220620221208SA

OFF

SHIPMENT

STANDBY

NORMAL

Battery pack

connected

Trigger from NSHIP

VNSHIP > VNSHIP_TH

for t > TNSHIP_FIL

GO2SHIP command or

NVM Trimming &

Calibration corruption

Battery pack

disconnected

GO2STBY

command or

VREG_NORM_UV

event

Trigger from WAKEUP

VWAKEUP > VWAKEUP_TH

for t > TWAKEUP_FIL

VREG_STBY_UV

event

NSHIP=VB

GO2SHIP command

3.1.1

Shipment - DEEP SLEEP

The SHIPMENT - DEEP SLEEP state is recommended for pack shipping and storage purposes. When in this

state, L9961 current consumption from VB pin is reduced to just IVB_SHIP, allowing long periods of inactivity to

reduce battery pack discharge.

When the battery pack is first applied (L9961 receives VB supply for the first time), the device transitions to either

shipment - DEEP SLEEP state or NORMAL state depending on NSHIP pin. If NSHIP is biased to VB pin, the

device starts in NORMAL State, otherwise the device begins in SHIPMENT - DEEP SLEEP state.

The device can enter SHIPMENT - DEEP SLEEP from NORMAL state upon receiving a GO2SHIP command

through I2C communications (GO2SHIP command is asserted by setting the GO2SHIP bit to ‘10’ in the register

0x21) or if VREG voltage drops below the minimum level (VVREG_STBY_UV) required to supply the device.

To avoid inadvertent reactivation, the NSHIP pin shall be set low before sending the GO2SHIP command, and it

shall be kept low during the transition to SHIPMENT - DEEP SLEEP.

Sending a GO2SHIP command while NSHIP is high will cause the device to move to STANDBY state.

3.1.2

STANDBY

The STANDBY state is recommended to manage short periods of inactivity, where wakeup from MCU is needed.

While in STANDBY, L9961 current consumption from VB pin is reduced to IVB_STBY.

The device is powered but no system functions are available, except WAKEUP sensing and VREG regulator

which operates with reduced performance charateristics While VREG is operational, the FAULTN_SAFE pin is

released allowing the MCU to operate in lower power mode.

STANDBY state can be reached from NORMAL state, upon receiving a GO2STBY command through I2C

communications (GO2STBY command is asserted by setting the GO2STBY bit to ‘10’ in the register 0x22) or

if VREG drops below the minimum level (VVREG_NORM_UV) required for L9961 to correctly perform its normal

features.

L9961

Functional description

DS14012 - Rev 1

page 9/63

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