TA8221 Ver la hoja de datos (PDF) - Toshiba
Número de pieza
componentes Descripción
Fabricante
TA8221 Datasheet PDF : 16 Pages
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TA8221AHQ / ALQ
5. Muting function
Through setting pin(1) (mute terminal) at about 1V or less, muting
becomes possible.
The interval circuit of IC is shown in Fig.5.
When pin(1) is set to low, Q1 and Q2 are turned to on, the charge
of the ripple condenser is discharged and the bias is cut. The mute
amount of 60dB or over can be obtained.
Since this muting function rapidly discharge the charge of the ripple
filter capacitor of pin(8), the pop noise is generated by the DC
fluctuation of the bias section.
Therefore, this muting function is not appropriate to the audio muting but it
is effective in muting at VCC→on.
6. Rapid ripple discharging circuit at the time of VCC off
This circuit is effective in such a mode where the VCC and the stand−by terminals become high / low
simultaneously ; for instance, for a pop noise produced when the power is turned on / off repeatedly by operating
the ignition key.
If VCC is off, VCC≒7V is detected internally on IC and
(1) The power stage bias circuit is cut, and
(2) Pin(8) : Ripple capacitor is rapidly discharged by turning Q3 on and then Q1 and Q2 on.
(Precaution 1)
When the stand−by terminal was put to the low level after the ripple rapid
discharging circuit was operated (VCC≒7V) at the time when VCC was turned
off, a pop noise may be generated. Therefore, VCC which makes the stand−by
terminal low shall be set at 8V or above so that (1) the stand−by terminal is
put at the low level and (2) the ripple rapid discharging circuit is turned on
when VCC is turned off (in order of (1) and (2)).
An example of application is shown in (Fig.7).
5
2006-04-28
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