CS44800 datasheet(44/81 Pages) CIRRUS

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DS632PP1

CS44800

5.1.4

Recommended Power-Down Sequence

1. Mute all channel outputs by setting the corresponding CHxx_MUTE bits to ‘1’b.

2. When driving a single-ended (half-bridged) power output stage, set the RAMP[1:0] bits to ‘01’b and

the required ramp speed, to initiate a ramp cycle when the channel is powered down.

3. Power down each channel’s PWM modulator by setting the PDN_PWMxx bit to ‘1’b. If single-ended,

this will initiate a sequence which will slowly decrease the DC voltage, from Vpower÷2 to 0 V, across

the AC-coupling capacitor.

4. The ramp-down function can be configured to cause an interrupt condition when the ramp period has

completed. This will be indicated by an active INT signal.

5. Once the ramp-down sequence has completed, set the appropriate GPIO pin, or other control signal,

to power down the power output stage.

6. For full-bridged power output stage configurations, the ramp-down sequence is not required. Powering

down the power output stage will not cause an audible pop from the speaker.

7. Concurrently with the ramp-down sequence, if desired, stop all clocks on the DAI interface

(DAI_MCLK, DAI_SCLK, DAI_LRCK).

8. Set the PDN bit to ‘1’b to put the CS44800 in the power down state.

Set PSR_EN = 1b

Set PSR_EN = 0b

Read DEC_OUTD[23:0]

3FEF90h <

DEC_OUTD[23:0] <

400FFFh?

Done

DEC_OUTD[23:0] >

400FFFh?

PSR =CPSR - 9Bh

Set PSR_RESET = 1b

PSR =CPSR + 9Bh

Figure 30. PSR Calibration Sequence

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