Release

CAP-XX Announces BriteSound™ Power Architecture to Pump up the Volume in Music Phones

CAP-XX supercapacitors double audio power for richer-sounding music and handle peak power demands to eliminate distortion during wireless transmissions

Sydney, Australia – June 12, 2007 – CAP-XX Limited (LSE:CPX) today announced its BriteSound™ power architecture for mobile phones. In a BriteSound™ phone, a CAP-XX supercapacitor provides a boost in peak power (more than 5 watts) which can double and sometimes triple audio power for richer-sounding music, and eliminate the buzzing and distortion that's common when transmitting wireless data while listening to music.

"With MP3-ready handsets growing in popularity, consumers want an iPod-quality audio experience without the distortion that interrupts music when the phone has to handle other peak-power functions," said CAP-XX CEO Anthony Kongats. "We are working with key mobile-phone manufacturers and expect the first designs that are power-boosted by our supercapacitors to hit the market in 2007."

BriteSound™ is the second CAP-XX BritePower architecture for mobile phones, joining the BriteFlash™ solution for high-brightness LED flash. In a power-management role supporting the battery, thin-form supercapacitors improve talk time, battery life, flash power, and audio quality, without compromising the handset's thin profile.

Audio Quality Problems in Music Phones:

A mobile phone's audio quality depends on its audio amplifiers' power output and its speakers' impedance. Typically, a standard 3.6-volt battery powers two class D amplifiers to drive a pair of 8-ohm speakers. In the CAP-XX tests, this set-up delivered peak power of 1.2 watts (W) to 2.25W. This lack of power can result in thin-sounding music with a weak bass beat.

Another problem arises when the battery becomes taxed from simultaneous peak power demands to transmit wireless data and respond to a network poll [networks periodically poll phones to locate them and determine needed transmit power] while the user is also listening to music. The battery voltage droops, and the audio amplifier supply voltage may droop enough to cause distortion which the user hears as a "click." This problem is worse in GSM/GPRS/EDGE phones which require particularly high power for radio-frequency (RF) transmission.

In addition, a 1-Amp or greater peak-power demand on the battery will cause a ripple in the audio amplifier supply voltage which the user hears as audio noise, or as a 217Hz buzz during a phone call.

Managing Mobile Phone Audio Power with a Supercapacitor:

In the BriteSound™ power architecture, a 2.4mm-thin, 0.55-farad, 85-milliohm dual-cell CAP-XX HS206 supercapacitor delivers 5W power-bursts to drive peak-power functions such as audio and LED Flash.

A battery covers the phone's average audio power needs of 0.5 to 1W, recharging the supercapacitor between bursts. This leaves enough battery power to handle data transfers and network polls without compromising audio power, eliminating both the distortion and "clicks" normally heard.

The supercapacitor powers the audio amplifier at 5 volts, compared to 3.6 volts directly from a battery, thereby doubling peak audio power for full-sounding music with a strong bass beat.

The supercapacitor also reduces noise by supplying peak power with less voltage droop than the battery would, and eliminates any 217Hz buzz when a GSM/GPRS/EDGE phone transmits by protecting the audio amplifier from other peak loads the battery supplies such as the RF Power Amplifier.

Because the supercapacitor supplies high-peak currents, designers can use higher-quality 4-ohm instead of standard 8-ohm speakers, further doubling peak audio power. Designers also save space and cost because they can size the phone's battery and power circuitry to cover average power consumption rather than peak loads.

Tests Comparing Mobile-Phone Audio Quality and Power:

CAP-XX used three cases for comparing audio quality and power, testing typical mobile-phone audio circuits both with and without a supercapacitor. To test the difference in power that 4-ohm versus 8-ohm speakers would make, CAP-XX simulated the effect by attaching a second set of identical 8-ohm speakers in the supercapacitor-powered set-ups.

To test a bass beat and a network poll, CAP-XX built two test circuits each with two class D audio amplifiers, one powered by a battery to drive a pair of 8-ohm speakers, the other supported by a supercapacitor to drive two pairs of 8-ohm speakers.

Bass Beat:

CAP-XX used a 100Hz bass beat lasting 120 milliseconds repeated every 0.5 seconds to test speaker power and battery current. The supercapacitor tripled peak audio power from 1.65W to 5.2W for fuller-sounding music. For graphs showing test results, see CAP-XX Photo Gallery.

Network Poll:

CAP-XX simulated a GSM/GPRS/EDGE network poll while listening to music by applying a two-amp, 1.15-millisecond power pulse while the audio amplifier was playing a 1KHz tone. The supercapacitor protected the audio amplifier from the battery voltage droop, eliminating distortion during wireless transmission. For graphs showing test results, see
CAP-XX Photo Gallery.

Listening to a Piece of Music:

The company played a piece of music to compare the unmodified MPS60 to the supercapacitor-powered one. The supercapacitor-modified setup more than doubled peak audio power from 2.24W to 4.96W, so music sounded fuller and richer. For visuals showing modified set-up and test results, see CAP-XX Photo Gallery.

About CAP-XX

CAP-XX supercapacitors enable manufacturers to make smaller, thinner, longer-running portable electronics such as cell phones, PDAs, medical devices, AMRs and notebooks. The company, which is listed on the Alternative Investment Markets (AIM) in London, is based in Sydney, Australia, has additional production facilities in Malaysia, and sales offices in London, UK, South Carolina, USA and Taipei, Taiwan. For more information visit http://www.cap-xx.com or email sales@cap-xx.com.

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Notes: For all BriteSound™ test-result visuals, see BriteSound™ in the Photo Gallery. For technical details, a white paper is available.

PR Contact:

Michelle Moody
Moody & Associates
Michelle Moody email
+1.214.363.3460 (Central time)