System Functions: Deployment

For the deployment output stages to be activated, the appropriate signals must be received from two different sensors, i.e. the B-pillar satellite and the MRS control-unit sensor.

In electrical-system statuses from Terminal R "ON" onwards, the MRS4RD control unit is supplied with power and is ready for operation on completion of the pre-drive check. The deployment capacitor, which acts as a power reserve, is charged to approx. 26 V via a switching regulator. The deployment capacitor provides the back-up power supply in the event of a crash in which the battery power supply is cut off.

The deployment capacitor, which provides the deployment power for the deployment output stages is controlled by a safety switch (trigger switch). The safety switch is operated by the microprocessor.

The deployment output stages consist of a high-side and a low-side power switch. The high-side power switch switches the deployment current and the low-side power switch switches the earth current. The high-side and low-side power switches are also used to check the deployment circuits as part of the pre-drive check.

The incoming sensor signals are analyzed by the analyzer module and passed on to the microprocessor. The microprocessor performs the deployment-algorithm calculations. The calculation results are compared with the event/deployment matrix and a decision reached as to the deployment of the various detonator pellets.