TA8270H
Block Diagram
C
5
1
TAB
20
V
CC1
6
V
CC2
OUT1 (+)
9
C
1
11
IN1
PW-GND1 8
OUT1 (−)
C
7
R
2
R
2
C
7
C
3
R
L
RF
7
OUT2 (+)
C
1
12
IN2
PW-GND2 2
OUT2 (−)
C
7
R
2
R
2
C
7
5
R
L
RR
3
CENTER
16
C
6
OUT3 (+)
C
1
15
IN3
PW-GND3 18
OUT3 (−)
C
7
R
2
R
2
C
7
17
R
L
LF
19
OUT4 (+)
C
1
14
IN4
PW-GND4 24
OUT4 (−)
C
7
R
2
R
2
C
7
21
R
L
LR
23
PRE-GND
13
RIP
10
C
2
STBY
4
DIAGNOSIS
MUTE
OUT
25
22
R
1
C
4
: PRE-GND
: PW-GND
000707EBF2
•
This product generates heat during normal operation. However, substandard performance or malfunction may cause the product
and its peripherals to reach abnormally high temperatures.
The product is often the final stage (the external output stage) of a circuit. Substandard performance or malfunction of the
destination device to which the circuit supplies output may cause damage to the circuit or to the product.
•
The products described in this document are subject to the foreign exchange and foreign trade laws.
•
The information contained herein is presented only as a guide for the applications of our products. No responsibility is assumed by
TOSHIBA CORPORATION for any infringements of intellectual property or other rights of the third parties which may result from its
use. No license is granted by implication or otherwise under any intellectual property or other rights of TOSHIBA CORPORATION or
others.
•
The information contained herein is subject to change without notice.
2
TA8270H
Caution and Application Method
(Description is made only on the single channel.)
1. Voltage Gain Adjustment
This IC has no NF (negative feedback) terminals. Therefore, the voltage gain can’t adjusted, but it makes
the device a space and total costs saver.
Amp. 2A
Amp. 1
Input
Amp. 2B
Figure 1
Block Diagram
The voltage gain of Amp.1:
G
V1
=
0 dB
The voltage gain of Amp.2A, B:
G
V2
=
20 dB
The voltage gain of BLT Connection: G
V (BTL)
=
6 dB
Therefore, the total voltage gain is decided by expression below.
G
V
=
G
V1
+
G
V2
+
G
V (BTL)
=
0
+
20
+
6
=
26 dB
2. Stand-by SW Function
(pin 4)
By means of controlling pin 4 (stand-by terminal)
to high and low, the power supply can be set to ON
and OFF. The threshold voltage of pin 4 is set at
about 3V
BE
(typ.), and the power supply current is
about 2
µA
(typ.) at the stand-by state.
V
CC
ON Power
OFF
4
10 kΩ
≈
2V
BE
to BIAS
CUTTING CIRCUIT
Control Voltage of pin 4: V
SB
Stand-by
ON
OFF
Power
OFF
ON
V
SB
(V)
0~1.5
3~V
CC
Figure 2 With pin 4 set to High,
Power is turned ON
Adjustage of Stand-by SW
(1)
(2)
Since V
CC
can directly be controlled to ON or OFF by the microcomputer, the switching relay can be
omitted.
Since the control current is microscopic, the switching relay of small current capacity is satisfactory
for switching
3
TA8270H
Large current capacity switch
BATTERY
RELAY
BATTERY
V
CC
V
CC
– Conventional Method –
FROM
MICROCOMPUTER
Small current capacity switch
BATTERY
DIRECTLY FROM
MICROCOMPUTER
BATTERY
Stand-By V
CC
Stand-By V
CC
– Stand-by Switch Method –
Figure 3
3. Muting Function
(pin 22)
By means of controlling pin 22 less than 0.5 V, it can make the audio muting condition.
The muting time constant is decided by R
1
and C
4
and these parts is related the pop noise at power
ON/OFF.
The series resistance; R1 must be set up less than 10 kΩ to get enough muting attenuation.
The muting function have to be controlled by a transistor, FET and
µ-COM
port which has I
MUTE
>
250
µA
ability.
Pin 22 terminal voltage has the temperature characteristics of 4.6 V (low temperature) to 3.2 V (high
temperature).
Therefore, it is need to design with attention as using the microcontroller of which operating voltage is
less than 5 V.
Terminal 22 may not be pulled up and shall be controlled by OPEN/LOW.
When it is obliged to do, it must be pulled up via diode, because it has to defend flowing reverse current
to internal circuit of pin 22.
<Recommended Application>
ATT – V
MUTE
20
I (100
µA)
I
MUTE (OFF)
22
C
4
R
1
A
(dB)
10 kΩ
0
5 kΩ
Mute attenuation ATT
I
MUTE
V
MUTE
−20
−40
−60
−80
−100
0
0.4
0.8 1 1.2
1.6
VCC
=
13.2 V
Po
=
10 W
PL
=
4
Ω
f
=
1 kHz
BW
=
400~30 kHz
2
2.4
2.8 3
<Application for pulled up>
I (100
µA)
I
MUTE (OFF)
22
C
4
R
1
I
MUTE
V
MUTE
Point A voltage: VMUTE
(V)
Figure 4
Muting Function
Figure 5
Mute Attenuation
−
V
MUTE
(V)
4
TA8270H
4.
Center Amp Pin: Center (pin 16)
Output from the center amp, which determines the
reference voltage for output in the IC, is connected to
this pin.
Connecting a capacitor to the pin rejects the ripple
component, reducing the distortion ratio of the audio
output.
CENTER
16
Center amp
PW-GND
Figure 6
5.
CENTER
Diagnosis Output
(pin 25)
This diagnosis output terminal of pin 25 has open collector output structure on chip as shown in Figure 7.
In case diagnosis circuit that detect unusual case is operated, NPN transistor. (Q1) or (Q2) is turned on.
It is possible to protect all the system of apparatus as well as power IC protection.
In case of being unused this function, use this IC as open-connection on pin 25.
5V
Output clip
detector
Output short
protector
Over voltage
protector
5.8 kΩ
Output offset
voltage detector
25
Q2
5V
Q1
GND
t
Q1 is turned on
Q2 is turned on
pin 25: Open collector output (active low)
Figure 7
5.1
Self Diagnosis Output
In Case of Shorting Output to V
CC
/GND or Over Voltage Power Supplied
NPN transistor. (Q1) is turned on.
Threshold of over voltage protection: V
CC
=
22 V (typ.)
5V
µ-COM
LED/LCD
ALARM
(Flashing)
(Announcement from a speaker.)
(Relay
→
OFF)
25
REGULATOR
→
OFF
MEMORY (Count and record)
Figure 8
5.2
In Case of Shorting Output to Output
Application 1
NPN transistor. (Q1) is turned on and off in response to the input signal voltage.
5
ST MEMS传感器创意设计大赛专区
京公网安备 11010802033920号
Copyright © 2005-2026 EEWORLD.com.cn, Inc. All rights reserved
电子工程世界
