tb2901h TOSHIBA Semiconductor CORPORATION, tb2901h Datasheet - Page 4

• Manufacturer Part Number: tb2901h
• Description: Maximum Power 47 W Btl 4-ch Audio Power Ic
• Manufacturer: TOSHIBA Semiconductor CORPORATION

3. Muting Function
Figure 4 Muting Function
Audio muting function is enabled when pin 22 is Low. When the time constant of the muting function is
determined by R
the power or muting function is turned ON/OFF will vary according to the time constant. (Refer to Figure 4
and Figure 5.)
The pin 22 is designed to operate off 5 V.
Moreover, this terminal (pin 22) serves as the source switch of current of an internal mute circuit. And it is
designed so that the discharge current of this terminal (pin 22) may serve as 200 mA. The outside pull-up
resistor R
ex) When control voltage is changed in to 6 V from 5 V.
To obtain enough mute attenuation, a series resistor, R
5 V
R
1
6 V/5 V ´ 47 k = 56 k
C
1
4
is determind on the basic of this value.
22
1
and C
1 kW
Stand-By
(pin 22)
V
4,
CC
it should take into account the pop noise. The pop noise which is generated when
Small current capacity switch
Large current capacity switch
Mute ON/OFF
control
V
CC
Battery
– Standby Switch Method –
Battery
– Conventional Method –
Figure 3
4
Figure 5 Mute Attenuation - - - - V
1
-100
-120
From microcomputer
at pin 22 should be 47 kW or more.
-20
-40
-60
-80
20
0
0
V CC = 13.2 V
f = 1kHz
R L = 4 W
V OUT = 20dBm
V
Stand-By
CC
0.5
Pin 22 control voltage: V MUTE (V)
V
1
Relay
CC
ATT – V
1.5
MUTE
From
microcomputer
Battery
Battery
2
2.5
2002-11-06
TB2901H
MUTE
3
(V)