ta8276h TOSHIBA Semiconductor CORPORATION, ta8276h Datasheet - Page 6

• Manufacturer Part Number: ta8276h
• Manufacturer: TOSHIBA Semiconductor CORPORATION

Note 1: It is appeared by biased input DC voltage
5.3
5.4
current over 4 A flows, this IC makes a protection circuit operate and suppresses the current into a speaker.
circuit failure.(Note 1)
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.)
Prevention of speaker burning accident (In Case of Rare Short Circuit of Speaker)
Applications
25pin voltage that is smoothed out with LPF.
of LPF is changed according to an input signal.
(for example, Vth is set up to 4 V if 25pin is pulled up to 5 V line.)
When output terminals short-circuit to V
And when shorting OUT + to OUT -, “L” and “H” are switched according to an input signal.
Therefore, it is possible to judge how the power IC condition is if a micro-controller detects the
It is recommend that the threshold voltage (Vth) is set up as higher as possible because output level
Less than 4 W
Output voltage of L.P.F.
Current into a speaker
5 V
¯
¯
Operating point of protector
Figure 10
Figure 9
About 1 W
CC
6
or GND, the voltage of 25pin is fixed to “L”.
Operating point of protector
4 W
Speaker impedance
Output power
2002-02-13
TA8276H