TA8252H
TOSHIBA Bipolar Linear Integrated Circuit Silicon Monolithic
TA8252H
Max Power 37W BTL × 4ch Audio Power IC
The TA8252H is 4ch BTL audio power amplifier for car audio
application.
This IC can generate more high power: P
OUT
MAX = 37W
as it is included the pure complementary PNP and NPN
transistor output stage.
It is designed low distortion ratio for 4ch BTL audio power
amplifier,built−in stand−by function, muting function,clip
detector,and diagnosis circuit.
Additionally, the AUX.amplifier is built−in, it can make the beep
signal etc.output to 2 channnels (out
1
and 4).It contains various
kind of protectors for car audio use.
Features
·
High power
: P
OUT
MAX (1) = 37W (typ.)
(V
CC
=
14.4V,
f =
1kHz,
EIAJ max., R
L
= 4Ω)
: P
OUT
MAX (2) = 35W (typ.)
(V
CC
=
13.7V,
f =
1kHz,
EIAJ max., R
L
= 4Ω)
: P
OUT
(1) = 24W (typ.)
(V
CC
=
14.4V,
f =
1kHz,
THD =
10%,
R
L
= 4Ω)
: P
OUT
(2) = 21W (typ.)
(V
CC
=
13.2V,
f =
1kHz,
THD =
10%,
R
L
= 4Ω)
·
·
·
·
·
·
·
·
Built−in clip detector & diagnosis circuit.(pin(25))
Low distortion ratio: THD = 0.02% (typ.)
(V
CC
=
13.2V,
f =
1kHz,
P
OUT
= 5W, R
L
= 4Ω)
Weight: 9.8g (typ.)
Low noise: V
NO
= 0.10mV
rms
(typ.)
(V
CC
=
13.2V,
R
g
= 0Ω, G
V
= 26dB, BW = 20~20kHz)
Built−in stand−by switch function (pin(2))
Built−in multing function (pin(24))
Built−in AUX. amplifier from single input (pin(16)) to 2 channels output; out1 and 4
Built−in various protection circuit
: Thermal shut down, Over voltage, Out to GND, Out to V
CC,
Out to Out short.
Operating supply voltage: V
CC (opr)
= 9~18V
1
2002-10-30
TA8252H
Block Diagram
C
5
1
20
6
TAB
V
CC1
+
V
CC2
OUT1(+)
17
15
IN1
C
1
+
-
GND1
-
-
18
OUT1(-)
OUT2(+)
19
+
14
23
IN2
C
1
+
-
-
GND2
22
OUT2(-)
21
16
AUX IN
OUT3(+)
+
11
9
IN3
C
1
+
-
-
GND3
8
OUT3(-)
OUT4(+)
7
+
12
3
IN4
C
1
PRE-GND
13
+
-
-
GND4
4
OUT4(-)
5
RIP
10
CLIP OUT
&
STBY DIAGNOSIS OUT MUTE
2
25
24
+
C
2
-
+
R
1
-
C
4
C
3
R
L
R
L
R
L
R
L
+
2
2002-10-30
TA8252H
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. 1
Input
+
−
Amp. 2A
+
−
Amp. 2B
+
−
(Fig.1) Block diagram
The voltage gain of amp.1: G
V1
= 0dB
The voltage gain of amp.2A, B: G
V2
= 20dB
The voltage gain of BTL connection: G
V (BTL)
= 6dB
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(2))
By means of controlling pin(2) (stand-by terminal) to high
and low, the power supply can be set to on and off.
The threshold voltage of pin(2) is set at about 3V
BE
(typ.),
and the power supply current is about 2µA (typ.) at the
stand-by state.
V
CC
ON
OFF
Power
2
10kΩ
≈2V
BE
to Bias
cutting circuit
Control voltage of pin(2): V
(SB)
Stand-by
On
Off
Power
Off
On
V
(SB)
(V)
0~1.5
3~6
(Fig.2) With pin(2) set to High,
Power is turned ON
Adjustage of stand-by SW
(1) Since V
CC
can directly be controlled to on or off by the microcomputer, the switching relay can be omitted.
(2) Since the control current is microscopic, the switching relay of small current capacity is satisfactory for
switching
3
2002-10-30
TA8252H
Relay
Battery
V
CC
Large current capacity switch
Battery
V
CC
From
microcomputer
－
Conventional Method
－
Small current capacity switch
Directly from
microcomputer
Battery
Stand-By V
CC
Stand-By V
CC
Battery
―
Stand-by switch method
―
(Fig.3)
3. Multing function (pin(24))
By means of controlling pin(24) less than 0.5V, 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; R
1
must be set up less than
15kΩ,
we recommend
10kΩ.
The muting function have to be controlled by a transistor, FET and µ-COM port which has
I
MUTE
> 250µA ability.
Terminal (24) must not be pulled up and it shall be controlled by open / low.
ATT – V
mute
20
R1 = 15kΩ
10kΩ
5kΩ
C
4
I(100µA)
I
MUTE
(OFF)
24
R
1
A
Mute attenuation ATT (dB)
0
I
MUTE
V
MUTE
−20
−40
−60
−80
−100
0
VCC = 13.2 V
Po = 10 W
RL = 4
Ω
f = 1 kHz
0.4
0.8
1.2
1.6
2
2.4
2.8
Pin(24) voltage : V
mute
(V)
(Fig.4) Muting function
(Fig.5) Mute attenuation-Vmute (V)
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2002-10-30
TA8252H
4.AUX. input (pin(16))
The pin(16) is for input terminal of AUX. amplifier.
The total gain is 0dB by using of AUX. amplifier.
Therfore, the µ-COM can directly drive the AUX. amplifier.
Beep sound or voice synthesizer signal can be input to pin(16) directly.
µ-COM
20dB AMP.
IN
+
−
AUX-IN
16
−20dB
AUX AMP
+
OUT(+)
−
OUT(−)
(Fig.6) AUX input
5. Diagnosis output (pin(25))
The diagnosis output terminal of pin(25) has open collector output structure on clip as shown in Fig.7.
In unusual case that output terminal of power amp. is condition of output to V
CC
or output to GND short and
over voltage input mode, 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).
(Application)
5V
25
5V
25
V3
5V
GND
t
Clip detector
output
Diagnosis
output
µ-COM
LED/LCD
(Flashing)
Alarm (Announcement
from a speaker.)
Regulator→OFF
(Relay→OFF)
Memory (Count and record)
Outpout short or over voltage input
Pin(25): Open collector output (active low)
(Fig.7)
(Fig.8)
5
2002-10-30
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