L9678P datasheet(32/215 Pages) STMICROELECTRONICS

Il numero della parte	L9678P

Spiegazioni elettronici	Automotive user configurable airbag and battery cut-off IC

PDF	215 Pages

Scroll/Zoom	100%

Produttore elettronici	STMICROELECTRONICS [STMicroelectronics]

Homepage	http://www.st.com

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32 / 215 page

Start-up power control

L9678P, L9678P-S

32/216

DS11626 Rev 9

Figure 12. ER cap charging circuit

4.3.3

ER switch and COVRACT pin

L9678P has an integrated circuit that can operate as a crossover switch with Rds(on) = 1.5 Ω

nominal. The ER switch is automatically activated upon entering the PASSIVE mode.

Voltage difference between VIN and VER is monitored in order to prevent VER back-feeding

when VIN exceeds VER by 0.1V max. The ER switch is automatically deactivated upon the

above mentioned overvoltage detection. The ER control implements a thermal protection

and a current limitation guard to avoid in-rush charge current at ER switch enabling or at

fault condition for short to ground. During PASSIVE mode the discrete digital output pin

COVRACT is activated to allow for external optional cross-over switch control.

GAPGPS01119

ER_charge_ON = 1

ER_charge_ON = 0

Active_mode = 1

AND

SYS_CTL(ER_CUR_EN)=1

Default SYS_CTL(ER_CUR_EN) = 0 at SSM_RESET = 1

Active_mode = 0

SYS_CTL(ER_CUR_EN)=0

ER CAP charge control

SSM_Reset

L9678P Scheda tecnica(PDF) 32 Page - STMicroelectronics