Space-saving IC Supports the Adjust Audio Tuning Required in Flat-panel TV Sets

Designs of LCD, plasma, and other flat-panel TVs are moving to even thinner profiles and narrower screen frames. This trend is placing considerable restrictions on speaker placement and mandating the use of smaller, thinner speakers that make it more difficult for equipment designers to achieve good-quality sound and sufficient audio volume. That problem is becoming even more acute because there is a growing demand for greater audio quality as consumers show preferences for larger screen sizes. Moreover, even among the TV manufacturers that are maintaining continuity with the screen sizes and profiles of their current models, there is an increasingly desire to obtain precise tuning of sound production to suit different environments and set designs and also to enable product line expansions.

To provide a solution to these equipment design issues, Renesas now offers the R2J15116FP digital amplifier. This new IC incorporates a 24-bit audio digital signal processor (DSP) unit that showcases our analog expertise. It can perform sound-quality enhancement and audio tuning with a high level of efficiency.

The new chip supports pulse code modulated (PCM) digital audio signals input using IIS format, three-wire serial, or other methods. Input signals are processed in the DSP unit before being amplified by the digital amplifier and then output in stereo to two speakers with a maximum power of 15Wx2ch. By integrating the audio DSP unit and digital amplifier in a single 7mm × 7mm package, the mounting footprint has been reduced by approximately half compared to the previous Renesas solution, which was provided as two separate packages.

To improve sound quality, the audio DSP unit features a parametric equalizer function that performs detailed correction of the audio to match the frequency characteristics of the speakers. The device also includes an intelligent volume control function that uses proprietary Renesas techniques to change the sound volume more smoothly than the digital volume controls used in standard DSPs. Our analog expertise is particularly evident in the design of an internal feedback circuit that enhances the sound quality and performance of the audio signal by keeping the output level stable regardless of fluctuations in the power supply voltage.

The R2J15116FP digital amplifier includes a full set of the safety functions for preventing problems that might otherwise occur in abnormal situations. Besides the overcurrent, overheating, and low-voltage detection and protection circuits included in past stereo amplifier devices, a new function has been added, one that gives advance warning of overheating. It automatically lowers the volume to reduce excessive heat generation.

For the future, we plan to extend this product line further by broadening the scope of our audio DSP functions.

Specification of R2J15116FP