ta8271h TOSHIBA Semiconductor CORPORATION, ta8271h Datasheet - Page 5

• Manufacturer Part Number: ta8271h
• Manufacturer: TOSHIBA Semiconductor CORPORATION

4. AUX Input
5. Prevention of speaker burning accident
amplifier.
AUX amplifier.
input to pin 16 directly.
connected to PRE-GND (pin 13) via a capacitor.
current over 4 A flows, this IC makes a protection circuit operate and suppresses the current into a speaker.
circuit failure.(Note 1)
Note 1: It is appeared by biased input DC voltage
The pin 16 is for input terminal of AUX
The total gain is 0dB by using of AUX amplifier.
Therefore, the m-COM can directly drive the
BEEP sound or voice synthesizer signal can be
When AUX function is not used, this pin must be
When the direct current resistance between OUT + and OUT - terminal becomes 1 W or less and output
This system makes the burning accident of the speaker prevent as below mechanism.
<The guess mechanism of a burning accident of the speaker>
Abnormal output offset voltage (voltage between OUT + and OUT -) over 4 V is made by the external
The speaker impedance becomes 1 W or less as it is in a rare short circuit condition.
The current more than 4 A flows into the speaker and the speaker is burned.
(for example, large leakage of the input capacitor, short-circuit between copper patterns of PCB.)
(pin 16)
Less than 4 W
Current into a speaker
¯
¯
Figure 9
About 1 W
5
(In Case of Rare Short Circuit of Speaker)
Operating point of protector
m-COM
4 W
AUX-IN
Speaker impedance
IN
Figure 6 AUX Input
16
AUX AMP
-
20dB
20dB AMP.
2002-02-13
TA8271H
OUT (+)
OUT (-)