E981.18A39FB ELMOS Semiconductor, E981.18A39FB Datasheet - Page 30

• Manufacturer Part Number: E981.18A39FB
• Description: Motor / Motion / Ignition Controllers & Drivers 8ch squib driver
• Manufacturer: ELMOS Semiconductor
• Type: Airbag Squib Driverr

Specifications of E981.18A39FB

• Rohs: yes
• Product: Electromechanical Drivers
• Operating Supply Voltage: 5 V
• Supply Current: 4.3 mA
• Operating Temperature: - 40 C to + 95 C
• Mounting Style: SMD/SMT
• Package / Case: QFN-44
• Number Of Outputs: 8
• Power Dissipation: 3.2 W

8-Channel Airbag Squib Driver
PRELIMINARY INFORMATION - AUG 01, 2011
TxL Short circuit detection:
In Normal Mode (deployment), the over voltage detection will shut off the driver after a specified time
T
there is a timer implemented, counting the time duration, in which the TxL voltage exceeds the over
voltage detection threshold OV
TxL
output. CMPOUT=high means the Counter is running, whereas CMPOUT=low means the Counter is
halted but not reset and will be started from same position again if the CMPOUT goes to high again.
Thus a thermal overload of the LSD will be avoided if more than one TxL
done for overlapping switch on scenarios of different channels.
In Test-Low Mode, in order to reduced as much as possible the energy provided to the squib in case of
intermittent SC to battery, the over voltage detection will shut off the LSD driver as soon as an OV
condition is detected (T
The Low Side Driver remains in Off state, even if the OV condition disappears again.
The over voltage flags of all 8 channel are summarized in one MISO status register (BIT[4], see chapter
5.4.5 for a more detailed description).
To activate the LSD in deployment mode, following signals have to be set:
•
•
•
Important: No automatically switch off available for the LSD. The driver has to be switched off externally
by µP with the according SPI CMD.
To activate the LSD in TEST_LOW-Mode following signals have to be set:
•
•
To limit the pulse energy applied to the squib during transient short circuits to battery in Test Mode the
T
TEST_LOW Mode coincides with a static short circuit to battery. The short circuit event is visible at the
MISO output frame in this case.
5.7.3
Activating of TEST_UP or TEST_LOW mode will set an internal signal TM , like sketched in Fig. 16
below. This internal signal reduces the internal current references for the HSD and LSD current
limitation units to the test-mode level. Additionally this signal is used to limit the maximum gate voltage
of all HSD during a TEST_UP activation. (see chapter 5.11).
This document contains information on a pre-production product. ELMOS Semiconductor AG reserves the right to change specifications and information herein without notice.
ELMOS Semiconductor AG
OV_BLNK_TXL_NM
OV_BLNK_TM
CODELOCK to be opened by SPI CMD (0x71)
ARM pin to be set to logical high level
Finally switching on the driver by the according SPI CMD (TxL_ON)
TEST_LOW to be set by SPI CMD (0xEC)
Finally switching on the driver by the according SPI CMD
OFF
CMD. The start and stop function of the Counter is then directly triggered by the comparator
General considerations for test mode activation TEST_UP/ TEST_LOW
is set to 0µs. By this the LSD will be kept switched off also if the driver activation in
, and set the flag OV
OV_BLNK_TXL_TM
TxL_REF
TXL
= 0µs), and the OV
. The timer is enabled with the TxL
in MISO register. To withstand pulsed short circuits to battery,
Page 30 of 63
Data Sheet
TxL
flag is set in the MISO register.
ON
ON
CMD and is reset with a
CMD's are sent, like it is
QM-No.: 25DS0072E.00
E981.18