Cap-xx Regulatory News (CPX)

12 Jun 2007 16:03

CAP-XX Limited (LSE:CPX) today announced its BriteSound powerarchitecture for mobile phones. In a BriteSound phone, a CAP-XXsupercapacitor provides a boost in peak power (more than 5 watts)which can double and sometimes triple audio power for richer-soundingmusic, and eliminate the buzzing and distortion that's common whentransmitting wireless data while listening to music. £ "With MP3-ready handsets growing in popularity, consumers want aniPod-quality audio experience without the distortion that interruptsmusic when the phone has to handle other peak-power functions," saidCAP-XX CEO Anthony Kongats. "We are working with key mobile-phonemanufacturers and expect the first designs that are power-boosted byour supercapacitors to hit the market in 2008." £ BriteSound is the second CAP-XX BritePower architecture for mobilephones, joining the BriteFlash solution for high-brightness LED flash.In a power-management role supporting the battery, thin-formsupercapacitors improve talk time, battery life, flash power, andaudio 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 standard3.6-volt battery powers two class D amplifiers to drive a pair of8-ohm speakers. In the CAP-XX tests, this set-up delivered peak powerof 1.2 watts (W) to 2.25W. This lack of power can result inthin-sounding music with a weak bass beat. £ Another problem arises when the battery becomes taxed fromsimultaneous peak power demands to transmit wireless data and respondto a network poll (networks periodically poll phones to locate themand determine needed transmit power) while the user is also listeningto music. The battery voltage droops, and the audio amplifier supplyvoltage may droop enough to cause distortion which the user hears as a"click." This problem is worse in GSM/GPRS/EDGE phones which requireparticularly high power for radio-frequency (RF) transmission. £ In addition, a 1-Amp or greater peak-power demand on the batterywill cause a ripple in the audio amplifier supply voltage which theuser 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 5Wpower-bursts to drive peak-power functions such as audio and LEDFlash. £ A battery covers the phone's average audio power needs of 0.5 to1W, recharging the supercapacitor between bursts. This leaves enoughbattery power to handle data transfers and network polls withoutcompromising audio power, eliminating both the distortion and "clicks"normally heard. £ The supercapacitor powers the audio amplifier at 5 volts, comparedto 3.6 volts directly from a battery, thereby doubling peak audiopower for full-sounding music with a strong bass beat. £ The supercapacitor also reduces noise by supplying peak power withless voltage droop than the battery would, and eliminates any 217Hzbuzz when a GSM/GPRS/EDGE phone transmits by protecting the audioamplifier from other peak loads the battery supplies such as the RFPower Amplifier. £ Because the supercapacitor supplies high-peak currents, designerscan use higher-quality 4-ohm instead of standard 8-ohm speakers,further doubling peak audio power. Designers also save space and costbecause they can size the phone's battery and power circuitry to coveraverage 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 asupercapacitor. To test the difference in power that 4-ohm versus8-ohm speakers would make, CAP-XX simulated the effect by attaching asecond set of identical 8-ohm speakers in the supercapacitor-poweredset-ups. £ To test a bass beat and a network poll, CAP-XX built two testcircuits each with two class D audio amplifiers, one powered by abattery to drive a pair of 8-ohm speakers, the other supported by asupercapacitor to drive two pairs of 8-ohm speakers. £ Bass Beat: £ CAP-XX used a 100Hz bass beat lasting 120 milliseconds repeatedevery 0.5 seconds to test speaker power and battery current. Thesupercapacitor tripled peak audio power from 1.65W to 5.2W forfuller-sounding music. For graphs showing test results:http://www.cap-xx.com/news/photogallery.htm#Bass £ Network Poll: £ CAP-XX simulated a GSM/GPRS/EDGE network poll while listening tomusic by applying a two-amp, 1.15-millisecond power pulse while theaudio amplifier was playing a 1KHz tone. The supercapacitor protectedthe audio amplifier from the battery voltage droop, eliminatingdistortion during wireless transmission. For graphs showing testresults: http://www.cap-xx.com/news/photogallery.htm#Network £ Listening to a Piece of Music: £ CAP-XX used a set of SonyEricsson MPS60 external speakers andaudio amplifier as a test bed. Engineers modified one set with asupercapacitor charged to 5V to power the audio amplifier, thenconnected a second pair of 8-ohm speakers to the original pair. £ The company played a piece of music to compare the unmodifiedMPS60 to the supercapacitor-powered one. The supercapacitor-modifiedsetup more than doubled peak audio power from 2.24W to 4.96W, so musicsounded fuller and richer. For visuals showing modified setup and testresults: £ http://www.cap-xx.com/news/photogallery.htm#Listen £ About CAP-XX: £ CAP-XX Limited, which is listed on the Alternative InvestmentMarkets (AIM) in London, is based in Sydney, Australia, has additionalproduction facilities in Malaysia, and sales offices in London, UK,South Carolina, USA and Taipei, Taiwan. For more information visithttp://www.cap-xx.com or email sales@cap-xx.com. £ Notes: For all BriteSound test-result visuals:http://www.cap-xx.com/news/photogallery.htm#Brite £ For technical details, a white paper is available:http://www.cap-xx.com/news/PumpUpTheVolume.pdf Copyright Business Wire 2007