CS42L56 datasheet(44/92 Pages) CIRRUS

44 / 92 page

DS851F2

CS42L56

When the rail voltages are set to VCP, the amplifiers will operate in their least efficient mode. When the

rail voltages are held at ±VCP/2, the amplifiers will operate in their most efficient mode, but will be clipped

if required to amplify a full-scale signal. Note: The ±VCP/2 curve ends at the point at which the output of

the amplifiers reaches 10% THD+N.

The benefit of Bi-Modal Class H is shown in the solid trace on the graph. At lower output levels, the am-

plifiers operate on the ±VCP/2 curve. At higher output levels, they operate on the ±VCP curve. The dura-

tion the amplifiers will operate on either of the two curves (±VCP/2 or ±VCP) depends on both the content

and the output level of the program material being amplified. The highest efficiency operation will result

from maintaining an output level that is close to, but not exceeding, the clip threshold of the ±VCP/2 curve.

4.6

Beep Generator

The Beep Generator generates audio frequencies across approximately two octave major scales. It offers

three modes of operation: Continuous, multiple, and single (one-shot) beeps. Sixteen On and eight Off times

are available.

It should be noted that the beep is generated before the limiter and may affect desired limiting performance.

If the limiter function is used, it may be necessary to set the beep volume sufficiently below the threshold to

prevent the peak detect from triggering. Since the master volume control, MSTxVOL[7:0], will affect the

beep volume, the DAC volume may alternatively be controlled using the PMIXxVOL[6:0] bits.

Figure 28. Class H Power to Load vs. Power from VCP Supply - 16



All Supplies= 1.8 V

RL = 16

CS42L56 Datasheet(PDF) 44 Page - Cirrus Logic