L9678P datasheet(153/203 Pages) STMICROELECTRONICS

номер детали	L9678P

подробное описание детали	Automotive user configurable airbag IC

PDF	203 Pages

Scroll/Zoom	100%

производитель	STMICROELECTRONICS [STMicroelectronics]

домашняя страница	http://www.st.com

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153 / 203 page

DocID029274 Rev 3

153/203

L9678P, L9678P-S

Safing logic

202

Figure 52. Scrap ACL state diagram

A specific waveform needs to be present on this input in order to instruct L9678P to arm all

deployment loops. L9678P is designed to support the Additional Communication Line (ACL)

aspect of the ISO-26021 standard, which requires an independent hardwired signal (ACL) to

implement the scrapping feature. The disposal signal may come from either the vehicle's

service connector, or the systems main microcontroller, depending on the end customer's

requirements.

The arming function monitors the disposal PWM input (ACL pin) for a command to arm all

loops for vehicle end-of-life airbag disposal. The disposal signal characteristic is shown in

Figure 53. To remain in Arming state, at least three cycles of the ACL signal must be

qualified. For the device to qualify the periodic ACL signal, the period and duty cycle are

checked. Two consecutive cycles of invalid disposal signal are to be received to disqualify

the ACL signal.

Figure 53. Disposal PWM signal

The disposal PWM signal cycle time and on time parameters can be found in the electrical

parameters tables.

L9678P датащи(PDF) 153 Page - STMicroelectronics