hi team,
my customer use 6304 in Infotainment, but meet pop noise even with power-down detect circuit to pull down STANDBY/ before PVDD and VABT go to 0. in this power-down detect circuit, Turn-on voltage is about 8.5V, and power-off shutdown voltage is about 7.7V.
1. Under the condition of playing sine wave such as 1KHz (sine wave frequency less than 3KHz, POP sound is more obvious), suddenly turn off the Standby pin to GND, it will produce POP sound
2. Under the condition of playing a sine wave such as 1KHz (sine wave frequency less than 3KHz, POP sound is more obvious), suddenly restart the Standby pin to 3.3V, the moment the output returns to normal, a POP sound will be generated , as Figure 3, Figure 4.
The above situation does not occur when playing digital silence, white noise, normal music, etc. It only occurs under sine wave conditions. When the speaker is changed to pure electronic synchronously, the POP sound waveform disappears. It is suspected that the continuous sinusoidal vibration of the speaker suddenly stops and starts. POP tone caused by the back EMF, as Figure 5.
please give some advice.
