E981.18A39FB ELMOS Semiconductor, E981.18A39FB Datasheet - Page 40

• 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
5.11
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•
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Fig. 20 shows the principle of the HSD Ilim control unit.
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
Provide HSD deployment current regulation output (configurable in LCM, HCM and test mode)
Internal polarization voltage and impedance for leakage detection
Short circuit to GND detection. The TxU short circuit detection is active during normal mode and test
mode. The SC
logic. After the time T
the SPI output. For a register reset a clear CMD must be set. (see chapter 5.14).
SC to GND protection in TM:
To provide a fast switch off during TM in case of a short to GND, the Driver gates will be pulled down
immediately, when the TxU voltage drops below the SC threshold. Additionally the HSD gate voltage
is clamped to V
SC to GND protection in NM (deployment):
In case of short to GND during deployment, the current limitation loop will enter the “fallback” mode:
the current limitation value will be reduced to reduce the PDISS of the driver. The “fallback” mode is
triggered by an overdrive of the inner loop regulation, sketched by the signal “sat” in Fig. 20. while
the voltage at the TxU pins drops below the nominal operating range given by the product of the the
min. squib resistance and the HSD I
different short circuit events to GND are sketched in Fig 23 below. The reduction of I
because the squib resistance is shorted by a parasitic short to GND at the TxU pin.
8 separate Firing Time Limiter (FTL) limit the maximum HSD switch on time, if the HSD switch off
command is missing. Each counter (CNTR) is started with the according TxU
the SPI switch on CMD. After reaching the counter limit, the internal FTL_TxU signal is switched to
logic high level and the according HSD is switched off. The counter value is coupled to the adjusted
current mode (LCM/HCM). For test purpose all 8 FTL outputs can be or and and combined and are
visible at the AMX pin with the according SPI CMD set (see chapter 5.14).
Terminal TXU, High Side Driver Outputs
TXU
TXU_TM
threshold is given in 5.11.1. The TxU SC-comparator output is propagated to the
during TM to minimize the short circuit pulse energy.
SC_DEL
is exceeded, the SC event is latched in a register an can be read out at
LIM_MIN
,. The different shapes of the HSD current regulation for
Page 40 of 63
Data Sheet
QM-No.: 25DS0072E.00
ON
signal, triggered by
LIM_TxU
E981.18
is possible