CS44800 datasheet(44/80 Pages) CIRRUS

44 / 80 page

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).

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

CS44800 Fiches technique(PDF) 44 Page - Cirrus Logic