1.5 Consumer and computer interface circuits

Technical background

As media content increasingly becomes a part of our daily lives, the need to transfer that content between devices with ease, speed and reliability is spurring development of many types of interfaces.

Figure 1, which shows the back panel of an A/V receiver from Pioneer Electronics, is an extreme example of a large number of interfaces on a single consumer electronic device. Having this many interfaces increases design complexity and device cost.

Electronics manufacturers face challenges in deciding what interfaces to implement on their devices to meet demanding consumer market requirements. This is becoming more challenging, as the space where you can put an interface connector shrinks with the size of the device. With the pervasiveness of high-quality digital formats, interfaces have transitioned from analog to digital. And given the need to reduce the size of the connector, the number of wires, power consumption and interface cost, digital interfaces are also moving from parallel data transmission to serial. To maintain the data bandwidth with fewer data lines, the data rate on serial interfaces is much higher than parallel interfaces.

Some of the factors that go into selecting an interface include:

• Analog or digital.
• Ease of use, plug-and-play (robust, interoperable).
• Meeting application needs (bulk transfer vs. streaming).
• Backward compatibility (USB 3.0, 2.0, 1.1).
• Upgrade path.
• Bandwidth-supported.
• Proprietary vs. industrial standards.
• Low silicon chip cost as well as system implementation cost.
• Power consumption.
• Mechanical connector dimensions.
• Regulatory compliance (electromagnetic interference).
• Firmware and software requirements.
• Royalty fees.

Figure 2 is an example of a digital interface replacing an analog interface, while providing ease of use and a higher-quality A/V experience.

Consumer and computing interface trends

Some of the current consumer and computing interface trends include:

• Analog interface to digital interface.
• Parallel interface to serial interface.
• Interface speed increasing (currently 10 Gbps).
• Lower power consumption.
• Lower implementation cost.
• Smaller connectors.
• Universal interface that aggregates multiple interfaces (e.g. Thunderbolt).

Device types

Many types of devices with different functions will help you implement the right interface on a system targeted for consumer and computing applications. Let's take a look at a few of them.

Bridge devices

These devices bridge, or translate, between two different interfaces. TI's TUSB3410 is an example of a bridge device that provides bridging between a USB port and an enhanced UART serial port.

There are many examples of TSUB3410 bridging functions at http://www.ti.com/product/tusb3410 . Figure 3 is a block diagram showing how the TUSB3410 helps designers convert a peripheral device with a legacy serial interface to a USB-compliant device.