Renesas announces compact, high-performance digital amplifier

The device, contained in a compact 7 mm x 7 mm package, accepts IIS digital audio signal input, performs signal processing using a built-in 24-bit audio DSP, and amplifies the result with a digital amplifier to deliver stereo output to two speakers at up to 15 watts per channel. Typically, thin flat-screen TVs require detailed tuning of their audio systems for different markets and screen sizes. This processing is usually performed in the preceding stage of this digital amplifier by the main DSP, which mainly handles tasks such as surround processing and decoding. This imposes a significant processing load. In the R2J15116FP, in contrast, processing for the volume control and the parametric equalizer*2 for optimizing the speaker characteristics is done by the built-in audio DSP. This reduces the load on the main DSP and makes it possible to generate a more varied and higher quality sound environment for video applications.

The R2J15116FP also achieves better audio signal performance and quality than conventional digital volume control implemented using a DSP, through the use of Renesas Technology’s exclusive intelligent volume function, which offers higher resolution when switching the volume level for smoother volume level transitions. The R2J15116FP also uses a feedback circuit to stabilize the output level when the power supply voltage fluctuates, an approach with a proven track record in products employing analog input. In addition to the volume control and seven-band parametric equalizer, there is a two-band tone control, a loudness function useful for low- and high-range expansion compensation, a power limiter function that allows setting of a user-defined maximum output level, and a dynamic range control (DRC) function that lowers the signal amplitude without distortion at high volume levels and raises it at low volume levels. Settings for all of these functions can be made flexibly from the MCU via the I2C bus.

Protection functions include detection of overcurrent, overheating, and low voltage, as well as a feature that provides warning in advance of overheating. This automatically lowers the volume to prevent the temperature from rising to a dangerous level. Additional functions include PLL unlock detection, which enhances the safety of signal input to the amplifier, and input signal error detection. This full complement of protection functions simplifies system design and boosts reliability.

The R2J15116FP uses a compact 48-pin HTQFP package, requires no heat sink, and delivers maximum stereo output of 15 watts per channel.