MIME-Version: 1.0 Content-Location: file:///C:/A1174539/HUYGENSMCDTECHNOLOGY.htm Content-Transfer-Encoding: quoted-printable Content-Type: text/html; charset="us-ascii" HUYGENS MCD TECHNOLOGY

HUYGENS MCD TECHNOLOGY

MCD stands for "MHz Class-D", A new amplifier technology from John.Fu(Fumac) and Zhaolian.Fu. This New Class D amplifier technology runs a very high sampling rate Frequency (from around 700KHz~2.6Mhz, at a fixed frequency). This technology enables us to produce amplifiers of high power(up to 800w), Low THD(0.00x%), Low phase-shift, and a Class A like sound all from a compact, cool running, environmentally friendly design, perfect for a HiFi, AV system, active speaker or professional amplifier.



MCD amplifiers feature two feedback paths (Figure 1), one to produce the Hi= gh Frequency oscillation frequency, the other for AF error feedback, this AF feedback includes the output filter to ensure load independent performance. By combining these two loops, you can create a system with both outstanding technical and subjective performance.





AF Error Feelback , Low THD
MCD has an AF error feedback from the speaker terminal , this feedback can = fix the large THD from the filter , so MCD can get a very low THD also at very = high power output. Figure 5: samples of THD in high power ou= tput .


THD spectrum analyzer of MCD-300 at 2W 6ohm,
THD=3D0.0035%(-87db) at 1k ,THD=3D0.0100%(-80db) at 7k ,THD=3D0.0112%(-79db= ) at 15k



THD spectrum analyzer of MCD-300 at 100W(rms) 6= ohm,
THD=3D0.016%(-76db) at 100Hz ,THD=3D0.012%(-78db) at 1k ,THD=3D0.016%(-74.5= db) at 7k

The Higher The Sample Frequency , The More Detail=
Previous Class D technology ran below 100KHz. This is not quick enough for full-range (10Hz~20KHz) audio performance, and c= an only be consider suitable for subwoofer (10Hz to 250Hz) applications.
More recently Class D designers have been able to increase the switching frequency of their designs to 200k~250k. These type of Class D amplifiers can produce close to full range audio (about 10hz ~18KHz= ). Typically these designs had great bass but poor treble. Still these amplifi= ers have found homes in AV systems, sub woofers, and Mid F= i applications. Figure 2 show level error at different speed of damp.
Bringing us up to date, there are some very good designs that now run at between 350¨C400KHz. These are the first designs that can reproduce the accepted "full bandwidth" (10Hz~22kHz) with f= inesse . However, the phase shift between bass and treble is to great to produce a fully cohesive sound. (Figure 3)..




High Frequency, Low Phase-shift, Low EMI
MCD runs at speeds of between 700KHz to 2.6MHz (up to 6 times faster then t= he current state of the art), It has an extended audio bandwidth from below 1H= z to beyond 60KHz with a simple filter (80KHz Low Pass Filter), as the high switching speed makes this possible.
Looking at he picture(Figure 3 and Figure 4), th= e MCD generates lower EMI, has less phase shift and has a greater bandwidth than other D Class amplifiers. With a AF error feedba= ck, the phase shift can be zero.




Balance response
A Butterworth filter is inside most of HIFI class-d amps, this is make the lowest EMI of damp, make it work well with others.
Some old class-d amp have a 3V carrier frequency output= (about 280mW, like a ).Class-d amp running in 400k have 0.8V(about 20mW to 4ohm, l= ike the output power of wireless microphone) . Through the speaker line, it will transmit to anywhere. MCD just have less than 0.1V(about 0.3mW ) carrier frequency output. It's very lower than the others.
A simple filter can't make the balance with audio frequency flag , low phase shift and lowest carrier frequency output, except the carrier frequency far away from the audioband. = But MCD can, because the very high frequency(700k~2.65MHz).(Figure 3 Figure 4 )=

Active loads=
Speakers have different loads, a 4ohm speaker some times between 2ohm to 8o= hm, sometimes we use a same AMP to drive different speakers, this is call active load character.
The simple filter of class-d amp response like Figure 5= , we found that the treble will different in the different load.
Figure 6 shows the active load character include 400k class-d amp and MCD, = we found that the MCD have a more flag response than the 400K class-d amp (13.= 7dB VS 7.5dB from 1ohm to 16ohm) . This is meaning MCD can driver different load with a same-like response.
MCD with a very strong current output, most types of MCD can driver 1ohm lo= ad.





15 Years Experience, offer customs design
John.Fu and ChaoLian.Fu are the designer of MCD . They have Experience worki= ng in RF design and AF design for 15 years, Good at super high speed PCB design a= nd Hi-FI audio design. This make the MCD work in ve= ry high performance. We offer our designs to other companies for Custom design all around the world.



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copy right: john.fu zhaoli= an.fu 2006~2007
email: fumac1@gmail.com (skype)
website: www.class-d.net