HT66FV1x0 Integrated Audio Amplifier Application Guideline
AN0486EN V1.10
9 / 16
June 8, 2021
Power On/Off Pop Noise
Pop noise is produced by the transient impact of various operations at the moment of power on or
power off of audio devices. To suppress pop noise, pay special attention to the following processes.
Process of Starting Voice Playing
(1)
Power On Sequence
Power On
SPI On
(pin PC7/SCSAB
→
1)
Ramp Up
Ready
SPI On
Enable VDDIO
PBS0[1:0]
→
11B
Enable SPI Pin
PCS1
→
0x55
set SAMLS, SACSEN
SPIAC0
→
0x00
SPIAC1
→
0x0C
set SPIAEN
SPIAEN
→
1
Return
When starting to read the Flash, setting the PC7/SCSAB pin from 1 to 0 will cause V33 to
change instantaneously, which will affect VCC resulting in unstable output. To solve this
problem, set the PC7/SCSAB pin from 1 to 0 and then initiate the ramp up process. This will
ensure a stable power supply when playing voices with reduced pop noise.
(2)
Ramp Up
When powering on, charge the output pins (SP+/SP-) gradually to a level of 1/2 V
DD
, wait for
a certain time until the power amplifier has a stable output, then output voice to the speaker. By
following this sequence, pop noise can be effectively suppressed. The specific settings are
summarised below.
Initial status:
(PLADH/PLADL)=0000H
,
DAEN=1
,
PAEN=0
,
MUTEB=1
,
USVC6~USVC0=000_0000
Increase the value of PLADH/PLADL gradually from 0000H to 8000H
Volume setup: USVC6~USVC0
=
target value
MUTEB=0
Enable the power amplifier
(PAEN=1)
, wait for a certain time until it has a stable output
Enable the speaker
(MUTEB=1)
for voice playing
