Automotive Infotainment block diagram

Design Considerations
Infotainment systems combine entertainment, multi-media and driver information functions in one module. They offer AM/FM or satellite radio, DC/DVD player for music and video, navigation system, data and multi media ports (USB, Blue tooth, line in, line out, video in) as well as general and vehicle status information.

Power management: The power supply is connected to the 12V or 24V board net and regulates down/up to voltages for DSP, uC, memory and ICs and functions in the infotainment system. In some cases there may be 10 or more different power rails, making the design of the power supply a critical task when trying to design for size, cost and efficiency.

Linear regulators with low quiescent current help reduce battery leakage current during standby operating modes (ignition off), are load dump voltage tolerant for directly battery connected devices, and need low drop out and tracking for low battery crank operation.

Beyond providing increased conversion efficiencies, switching power supplies provide EMI improvement with slew rate control of the switching FET, Frequency hopping, spread spectrum or triangulation method for attenuation of peak spectral energy, Low Iq, soft start for power sequencing and in rush current limitation, Phased switching for multiple SMPS's regulators to minimize input ripple current and lower input capacitance, higher switching frequency for smaller components (L and C's), and SVS functions for brown out indications

Communication interfaces allow data exchange between independent electronic modules in the car, the remote sub modules of the infotainment system as well as external devices like USB memory or video sources.

High Speed CAN (up to 1Mbps, ISO 119898) is a two wire, fault tolerant differential bus. With a wide input common mode range and differential signal technology it serves as the main vehicle bus type for connecting the various electronic modules in the car with each other. LIN supports low speed (up to 20 kbps) single bus wire networks, primarily used to communicate with remote sub functions of the infotainment system. LVDS interfaces are used to transfer large amounts of data (e.g. HD video data) via a high speed serial connection to an external location like a video screen.

The Audio input front end and audio output is often combined into a single Codec. The Audio line level input from the source is converted into digital samples by the ADC and feed to the system's DSP. On the output side ADCs convert the digital output an analog signal, which is amplified to the levels needed by the speakers or headphones used with the system. By using Class-D amplifiers the system’s power efficiency can exceed 90% while maintaining low THD. This improved efficiency leads to significant size, weight and heat reductions. TI’s class-D car audio solutions exhibit extremely low EMI levels and are being used in OEM systems with stringent EMC requirements.

The audio DSP performs I/Q demodulation and outputs digital audio and data. This includes functions like volume, treble, bass and sound effects, as well as more sophisticated features like mixing input channels and digitally process multiple channels, performing sound effects processing such as Dolby® Pro Logic® II, SRS® Circle Surround™ II, TruSound and other audio algorithms. The uC + DSP controls the user interface, bus interface, and network interface as well as GPS navigation and touch screen control. It is also used to process and output video data from multiple sources.

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