Audio devices upgrade TV sound systems

Audio processors and Class-D audio power amplifiers deliver a complete advanced TV audio subsystem.

Expanding its Advantiv advanced television solutions portfolio, Analog Devices has introduced audio processors and Class-D audio power amplifiers that deliver a complete advanced TV audio subsystem while allowing designers to meet multiple product performance and price targets.

Designed to work together, the chips provide all the critical subsystem functionality required for an advanced TV audio implementation, including an embedded processing engine to ensure big sound from small speakers; analogue interfaces for line inputs/outputs; analogue broadcast audio decoding and speaker output; flexible, multiformat digital interfaces for HDMI sources and all digital terrestrial and satellite broadcasts); and audio/video lip-sync delay correction and synchronisation.

"The engineering required for the audio processor and Class-D power stage amplifier to work well together is significant", says Martin Cotter, Product Line Director, Advanced Television Segment, Analog Devices.

"ADI has solved the design difficulties associated with this open-loop interface, thereby eliminating customary system-level concerns, such as 'pop/click' reduction and physical interfacing challenges".

"This reduces design cycle time, minimises system cost, and delivers a quality audio experience for consumers - key benefits for TV manufacturers with defined 12-month new product refresh cycles".

ADI's new ADAV4101, ADAV4312 and ADAV4322 audio processors incorporate a powerful, embedded processing engine to compensate for the space-constrained speakers in today's thin flat, LCD and plasma TV designs.

This "digital audio enhancement engine" does all the processing necessary to deliver the big sound required to match high-definition video quality.

This feature is coupled with high-performance multichannel 24bit analogue-to-digital convertors (ADCs) and digital-to-analogue convertors (DACs) that accept analogue line inputs from DVD/VCR players and set-top boxes and drive analogue audio to power amplifiers for speakers or auxiliary outputs.

"The ADAV43x2 and ADAV44x2 audio processors are not just input/output devices with lots of high performing digital interfaces, analogue interfaces and multiple ADCs and DACs doing advanced signal processing", says Cotter.

"They are enhanced, fully programmable audio processors, with full support for HD-ready and iDTV designs".

"They also support multistandard analogue broadcasts, such as BTSC, EIAJ, A2-Korea, A2-Europe and Nicam, from analogue terrestrial tuners via an on-chip demodulator and decoder".

The audio processors provide a range of flexible digital interfaces, with sample rate conversion, which ensures the devices are fully compatible with the requirements of interfacing to HDMI audio and digital tuners.

By default, the devices load a dedicated TV audio flow that incorporates full matrix switching to allow any input source type to be connected to any output.

As well as providing standard TV audio processing, they can also be designed to enable advanced audio features, such as full-room equalisation, surround-sound virtualisation or bass-frequency enhancement.

Many of these features are offered from Analog Devices or under licence from third-party suppliers, such as Dolby, SRS-Labs and BBE.

The audio processors also enable design engineers to customise the audio flow to conform to specific system or customer needs.

Analog Devices provides a range of tools, including the award winning SigmaStudio graphical design tool, to allow easy debug and verification of any customised implementations.

They also feature automatic volume control to compensate for volume changes during advertisements or when switching channels, dynamic bass, a multiband equaliser, and up to 400ms of delay memory for audio/video synchronisation.

ADI's audio processors are complemented by new Class-D amplifiers.

The ADAU1590, ADAU1592 and ADAU1513 are twin-channel Class-D amplifiers with the best performance of any audio power amplifiers in their class.

The new amplifiers have a 90% power efficiency rating at 8ohm and a 101dB dynamic range.

The ADAU1590 and ADAU1592 feature on-chip PDM (pulse-density modulation) and a closed-loop architecture that ensures premium audio amplification by conditioning a signal to compensate for output errors before it is sent to the speaker.

They also include integrated sigma-delta modulators that accept an analogue input signal and generate a switching output to drive the speakers directly.

The ADAU1590 and ADAU1592 achieve 0.005% THD+N (total harmonic distortion-plus-noise) while delivering 11.5W (stereo) and 18W (stereo) into 6ohm, respectively.

The low distortion, noise and PSRR (power supply rejection ratio) combine with the optimised interface of ADI's audio processor (ADAV4101/4312/4322) to suppress audio pops and clicks when the TV is turned on or off and eliminate residual background noise when the speaker volume is at its lowest setting.

The ADAU1513 Class-D power stage, delivering 14W (stereo) into 8ohms with 90% efficiency, is directly driven from the PWM digital outputs on the ADAV4201, ADAV4412 or ADAV4422 audio processor.

The power stage comprises thermal and output short-circuit protection with logic-level error flag outputs for interfacing to a system microcontroller along with reset and mute control of the power stage.

The ADAV4101, ADAV4312, ADAV4322, ADAV4201, ADAV4412 and ADAV4422 audio processors are available in production volume now.

They are available in 80-lead LQFPs (low-profile quad flat packages) and are pin-for-pin and software-register compatible.

The ADAU1590, ADAU1592 and ADAU1513 Class-D amplifiers are available in production volume now.

The ADAU1590, ADAU1592 and ADAU1513 amplifiers are available in 48-lead LFCSPs (lead frame chipscale packages) and 48-lead TQFPs (thin quad flat packages).

Back to top