ROHM announces industry’s first power supply ICs for hi-fi audio

ROHM has recently announced the availability of high-fidelity power supply ICs optimised for audio devices requiring high-resolution playback. The BD372xx series are the first audio power supply ICs to combine leading-edge analogue and sound reproduction technologies. In addition to integrating a newly developed fast response error amp circuit and low-noise architecture, multiple parameters that were shown to affect audio quality in the development and manufacturing processes were optimised via real-world listening tests, resulting in industry-leading performance in all key characteristics (voltage stability, noise level, and power supply symmetry) required by power supplies for audio equipment.

In recent years, the popularisation of high-resolution audio sources has increased the demand for audio components and devices that can provide even more accurate sound reproduction. At the same time, the power supplied to audio equipment has a significant effect on sound quality. As such the power supply IC plays an important role in supplying clean power with minimal voltage fluctuation and noise. Providing clean power involves optimising three key characteristics: voltage stability, noise level, and symmetry between positive and negative power supplies. However, until now there has not been an IC capable of meeting these needs, presenting an obstacle in achieving higher sound quality.

In response, ROHM has developed the industry’s first audio power supply ICs that excels in all three characteristics by combining proprietary power supply analogue design technology that leverages power processes with audio quality expertise. The result is a very clean power supply compared with conventional solutions, making it possible to achieve higher audio quality; including improved sound imaging (location and distance of sound source) and resolution (realism and depth).

Key features 

1. Delivers higher sound quality by providing clean power 

   1) Improved voltage stabilisation
   Incorporating a newly developed error amp circuit capable of high-speed response over a wide band minimises the effects of input voltage/output current fluctuations on the output voltage. The result is more faithful reproduction at the lower (bass) frequencies.

   2) Reduced noise
   Class-leading low noise is achieved by adopting a low-noise architecture that suppresses noise generated within the IC (4.6µVrms, 50x lower than conventional). This eliminates the influence of noise to deliver clearer sound with superior transparency.

   3) Power supply symmetrisation
   Besides positive power supply ICs, a negative type is offered that can be configured to achieve ideal symmetry in characteristics when used together. This makes it possible to improve sound image localisation and expand the sound stage.

   2. Lineup optimised for high-fidelity audio equipment 

The BD37201NUX is ideal for low-voltage digital devices such as DACs and DSPs, while the BD37210MUV (positive power supply) and BD37215MUV (negative power supply) are optimised for analogue devices (i.e. sound processors, current-voltage conversion amps) that operate using both positive and negative voltage supplies.

Lineup

See table here.

Applications

Hi-fi audio systems, portables, home audio, wireless speakers, and other equipment requiring high fidelity playback

Terminology

High resolution audio source

Unlike music on standard CDs which are played back at a sampling frequency of 44.1kHz and 16bit quantization bit rate, high-resolution audio sources typically require playback at greater than 96kHz and 24bit. In other words, the amount of information contained in high-resolution audio sources is much greater than in standard CD quality sources, resulting in better sound quality.

Hi-fi (high fidelity) audio

High quality audio designed to faithfully reproduce the original audio source.

www.rohm.com/eu