Emphasis Control (Dem[1:0]); Ramp Configuration (Address 05H); Ramp-Up/Down Setting (Ramp[1:0]); Ramp Speed (Ramp_Spd[1:0]) - Cirrus Logic CS44600 Manual

6-channel digital amplifier controller

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7.5.4

De-Emphasis Control (DEM[1:0])

Default = 00

00 - no de-emphasis

01 - 32 kHz de-emphasis filter

10 - 44.1 kHz de-emphasis filter

11 - 48 kHz de-emphasis filter

Function:

Enables the appropriate digital filter to maintain the standard 15 ms/50 ms digital de-emphasis filter re-

sponse.

7.6

Ramp Configuration (address 05h)

RESERVED

7.6.1

Ramp-Up/Down Setting (RAMP[1:0])

Default = 00

00 - Ramp-up and ramp-down are disabled

01 - Ramp-up is disabled. Ramp-down is enabled.

10 - Reserved

11 - Ramp-up and ramp-down are enabled. Note that after a ramp-up sequence has completed, audio will

not play until RAMP[1:0] is set to 01.

Function:

When ramping is enabled, the duty cycle of the output PWM signal is increased (ramp-up) or decreased

(ramp-down) at a rate determined by the Ramp Speed variable (RAMP_SPDx). This function is used in

single-ended applications to reduce pops in the output caused by the DC-blocking capacitor. When the

ramp-up/down function is disabled in single-ended applications, there will be an abrupt change in the out-

put signal. Refer to Section 5.1.1 .

If ramp-up or down is not needed, as in a full-bridge application, these bits should be set to 00. If ramp-

up or down is needed, as in a single-ended half-bridge application, these bits must be used in the proper

sequence as outlined in

Down Sequence" on page

7.6.2

Ramp Speed (RAMP_SPD[1:0])

Default = 01

00 - Ramp speed = approximately 0.1 seconds

01 - Ramp speed = approximately 0.2 seconds

10 - Ramp speed = approximately 0.3 seconds

11 - Ramp speed = approximately 0.65 seconds

Function:

This feature is used in single-ended applications to reduce pops in the output caused by the DC-blocking

capacitor. The Ramp Speed sets the time for the PWM signal to linearly ramp-up and down from the bias

point (50% PWM duty cycle). Refer to Section 5.1.1

RESERVED

RAMP1

"Recommended Power-Up Sequence" on page 43

45.

RAMP0

RESERVED

and

CS44600

RAMP_SPD1

RAMP_SPD0

"Recommended Power-

DS633F1

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