Document
TA8271HQ
TOSHIBA Bipolar Linear Integrated Circuit Silicon Monolithic
TA8271HQ
Max Power 41 W BTL × 4 ch Audio Power IC
The TA8271HQ is 4 ch BTL audio power amplifier for car audio application. This IC can generate more high power: POUTMAX = 41 W as it is included the pure complementary PNP and NPN transistor output stage. It is designed low distortion ratio for 4 ch BTL audio power amplifier, built-in stand-by function and muting function. Additionally, the AUX amplifier and various kind of protector for car audio use is built-in. Weight: 7.7 g (typ.)
Features
• High power: POUTMAX (1) = 41 W (typ.) (VCC = 14.4 V, f = 1 kHz, JEITA max, RL = 4 Ω) : POUTMAX (2) = 37 W (typ.) (VCC = 13.7 V, f = 1 kHz, JEITA max, RL = 4 Ω) : POUT (1) = 24 W (typ.) (VCC = 14.4 V, f = 1 kHz, THD = 10%, RL = 4 Ω) : POUT (2) = 21 W (typ.) (VCC = 13.2 V, f = 1 kHz, THD = 10%, RL = 4 Ω) • • • • • • • Low distortion ratio: THD = 0.02% (typ.) (VCC = 13.2 V, f = 1 kHz, POUT = 5 W, RL = 4 Ω) Low noise: VNO = 0.18 mVrms (typ.) (VCC = 13.2 V, Rg = 0 Ω, GV = 34dB, BW = 20 Hz~20 kHz) Built-in stand-by switch function (pin 4) Built-in muting function (pin 22) Built-in AUX amplifier from single input to 2 channels output (pin 16) Built-in various protection circuit : Thermal shut down, over voltage, out to GND, out to VCC, out to out short Operating supply voltage: VCC (opr) = 9~18 V
Note 1: Install the product correctly. Otherwise, it may result in break down, damage and/or degradation to the product or equipment. Note 2: These protection functions are intended to avoid some output short circuits or other abnormal conditions temporarily. These protect functions do not warrant to prevent the IC from being damaged. - In case of the product would be operated with exceeded guaranteed operating ranges, these protection features may not operate and some output short circuits may result in the IC being damaged.
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Block Diagram
C5
1 TAB
20 VCC1
6 VCC2 OUT1 (+) 9
C1
11
IN1 PW-GND1 8 OUT1 (−) 7 RL
OUT2 (+) 12 IN2
5 RL
C1
PW-GND2 2 OUT2 (−) 3
C6
16
AUX IN
OUT3 (+) 15 IN3
17 RL
C1
PW-GND3 18 OUT3 (−) 19
OUT4 (+) 14 IN4
21 RL
C1
PW-GND4 24 OUT4 (−) 23
PRE-GND
13 RIP 10 C2 STBY 4 R2 C7 MUTE2 25 C8 MUTE 22 R1 C4
: PRE-GND : PW-GND
Note3: Some of the functional blocks, circuits, or constants in the block diagram may be omitted or simplified for explanatory purpose.
C3
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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: GV1 = 8 dB The voltage gain of Amp.2A, B: GV2 = 20 dB The voltage gain of BLT Connection: GV (BTL) = 6 dB Therefore, the total voltage gain is decided by expression below. GV = GV1 + GV2 + GV (BTL) = 8 + 20 + 6 = 34 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 3VBE (typ.), and the power supply current is about 2 µA (typ.) at the stand-by state.
VCC ON Power OFF 4 10 kΩ ≈ 2VBE to BIAS CUTTING CIRCUIT
Control Voltage of pin 4: VSB
Stand-by ON OFF Power OFF ON VSB (V) 0~1.5 3~VCC
Figure 2 With pin 4 set to High, Power is turned ON
Adjustage of Stand-by SW
(1) (2) Since VCC 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
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Large current capacity switch BATTERY RELAY BATTERY
VCC
VCC – Conventional Method –
FROM MICROCOMPUTER
Small current capacity switch BATTERY
DIRECTLY FROM MICROCOMPUTER BATTERY
Stand-By VCC
Stand-By VCC – 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 R1, C4 and C8 and these parts is related the pop noise at power ON/OFF. The series resistance; R1 must be set up less than 5 kΩ. The muting function have to be controlled by a transistor, FET and µ-COM port which has IMUTE > 50 µA ability.
ATT – VMUTE
0 −10
I (20 µA) IMUTE (OFF)
(dB)
−20 −30 −40 −50 −60 −70 −80 −90 −100 1.2 1.4 1.6
R1 = 5 kΩ
25 C8
ATT
22 C4
R1 IMUTE
A
Mute attenuation
R1 = 2.2 kΩ
VMUTE
VCC = 13.2 V Po = 10 W RL = 4 Ω f = 1 kHz 1.8 2.0 2.2 2.4 2.6 2.8
Point A voltage: VMUTE
(V)
Figure 4 Muting Function
Figure 5 Mute Attenuation − VMUTE (V)
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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. Therefore, the µ-COM can directly drive the AUX amplifier. BEEP sound or voice synthesizer signal can be input to pin 16 direc.