Automotive emergency call system reference design

March 25, 2013 // By Graham Prophet
Texas Instruments has introduced a complete reference design that provides designers all the analogue and embedded processing integrated circuits required for automotive emergency call (eCall) systems. Vehicles equipped with eCall systems automatically place calls to an emergency service centre in the event of an accident.

Featuring the TPA3111D1-Q1 high efficiency mono Class D audio amplifier and the TPS43330-Q1, single-boost, dual synchronous buck controller with ultra low quiescent current, TI’s automotive eCall reference design offers a low-cost solution that is scalable for other automotive applications, such as telematics, stolen vehicle tracking and HEV/EV sound generation. It also incorporates the TLV70033-Q1 voltage regulator with low quiescent current and the MSP430F2232 16-bit ultra-low power microcontroller.

TI says the design offers loud and clear audio quality with 10-W output power into 8 Ω with greater than 90% efficiency, and offers enhanced EMI suppression to improve sound immunity. This is imperative in an eCall system where external conditions can sometimes overwhelm the emergency call.

The TPS43330-Q1 pre-boost circuit supports automotive start/stop and boosts back-up battery supply voltage, allowing operation down to 2 V at the input. Combined with the Class D amplifier’s wide supply voltage range of 8 V to 26 V, the components in this reference design can be powered by a single-cell LiFePO4 battery, in case the car battery connection is severed in an accident.The components offered in this system provide over-voltage and load dump protection against input transients of up to 40 V. The Class D amplifier also supports power cycling and speaker open-load detection during initial power-up. These features ensure robust operation in harsh automotive environments and simplify failure analysis.

For more information; www.ti.com/autoecallrefdesign-pr-eu