L5965 datasheet(48/73 Pages) STMICROELECTRONICS

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6.1

Shutdown mode

In Shutdown Mode supply batteries (VBAT1/VBAT2/VINx) are not present and all regulators are OFF.

A rising edge on VBAT1 line (higher than Power On Reset threshold) moves L5965 to STANDBY Mode, if the

PMIC has been programmed. Otherwise the L5965 moves to OTP programming mode.

6.2

Standby mode

In Standby mode, all the regulators are OFF, RESET_B is asserted and current consumption is very low. A low to

high transition on WKUP pin moves the IC to INIT Mode. If VBAT1 falls below POR threshold, the device goes

back to Shutdown Mode.

6.3

INIT mode

In INIT mode all the functional checks on analog and digital circuitry are performed:

•

OTP program checksum: data integrity is verified and OTP WR bit is checked

•

Analog BIST on Voltage monitors (UV/OV)

•

Analog BIST on Temperature monitors

•

RESET_B assertion and path is checked

•

LBIST (Digital BIST)

•

Check if main VBAT is ok

The operative range of the Analog BIST on Temperature monitor reaches up to 125 °C.

Main regulator GND LOSS comparator is active.

LBIST is always active, not only in INIT mode. In INIT mode, in case of issues during LBIST, the IC moves to

REC mode. Outside INIT mode, in case of issues during LBIST, the FAULT pin is asserted, and in case of Buck

State Machine check error, also the REC mode is entered.

Besides, LBIST includes:

Buck clock generation check;

Logic diagnostics;

Main State Machine check.

If all the checks are completed without any fail, L5965 moves to RAMPUP mode. In case of fail, the device moves

from INIT to REC state and the FAULT pin is asserted. A transition (High to Low) on WKUP moves the state

machine back to STBY, where the FAULT pin is de-asserted.

6.4

REC mode

L5965 goes to REC mode (recovery state) in case the Main Regulator or a regulator associated with the reset

activation fails. When the IC moves from active to stand-by state, the power down phase is activated. When the

IC moves from the active to REC state, all regulators switch off at the same time.

In this state, the FAULT pin is asserted and RESET_B is kept low. There are 2 ways to move the device out of

REC:

A transition High to Low on WKUP pin moves the IC back to STANDBY, where the FAULT pin is de-asserted.

If WKUP pin is kept High for a time longer than Twk_rec and the IC goes in REC mode less than a number

of times (3 times if inf_retrial_en = 0, infinite times if inf_retrial_en = 1), then the device moves from REC to

INIT and restarts again.

When the chip enters the REC mode, the IC is switched off. The outputs of the SMPS decrease slowly in order to

be ready for next power up phase. The outputs of the SMPS are pulled down to 0 V by an inner pull-down current.

The pull-down current of each regulator is typically 12 mA.

6.5

RAMPUP MAIN and SEC_UP

In RAMPUP MAIN status, the main regulator (selected by OTP bit) is turned on: when this phase ends, the state

machine moves to SEC_UP status where all secondary regulators are turned ON following the Power Up

sequence programmed by OTP. When the last regulator has finished its power up phase, the device moves to

ACTIVE Mode, where the SPI communication is allowed: all regulators that have to be turned on by SPI

command can now be enabled.

WKUP pin is not monitored in these transition phases.

Reset signal release is programmed via OTP: three OTP bits associate the reset signal to a regulator.

L5965

Shutdown mode

DS12567 - Rev 3

page 48/73

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