Other Solutions - Stereo, Closed Loop and Higher Powers.

STEREO

It is possible to duplicate the above solution to give a 2

channel stereo solution. However if the oscillator

frequencies are not locked together, a beat can occur

which is acoustically audible. This is undesirable. A

stereo solution which avoids this problem can be

achieved by synchronising the operating frequencies

of both ZXCD1000’s class D controller IC’s, by slaving

one device from the other. This is illustrated in Figure 8.

Great care must be taken when linking the triangle

from the master to the slave. Any pickup can cause

slicing errors and result in increased distortion. The

best connection method is to run two tracks, side by

side, from the master to the slave. One of these tracks

would be the triangle itself, and the other would be the

direct local ground linking the master pin9 ground to

the slave pin 9 ground.

A demonstration board, ZXCD1000EVSOL, is available

for a stereo 25W solution.

ZXCD1000

ISSUE 2 - APRIL 2002

9

MASTER

SLAVE

Figure 8 Frequency synchronisation for stereo applications