TB2904HQ Toshiba, TB2904HQ Datasheet - Page 6

• Manufacturer Part Number: TB2904HQ
• Manufacturer: Toshiba

Specifications of TB2904HQ

• No. Of Channels: 4
• Package: HZIP 25-P-1.00F
• Recommended Vcc (v): 13.2
• Rl=2 Ohm: Not Supported
• Rl=4 Ohm: 45W x 4
• Rl=8 Ohm: -
• Features/built-in Functions: 4 BTL channels, standby switch, mute, BiCD process, offset detection
• Operating Voltage (v): 9 to 18

5. Prevention of speaker burning accident
Note 1: It is appeared by biased input DC voltage
current over 4 A flows, this IC makes a protection circuit operate and suppresses the current into a speaker.
This system makes the burning accident of the speaker prevent as below mechanism.
When the direct current resistance between OUT+ and OUT− terminal becomes 1 Ω or less and output
(For example, large leakage of the input capacitor, short-circuit between copper patterns of PCB.)
<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
circuit failure.(Note 1)
The speaker imepedance becomes 1 Ω 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.
Less than 4A
↓
↓
Current into a speaker
Figure 8
About 1 Ω
6
(in case of rare short circuit of speaker)
Operating point of protector
4 Ω
Speaker Impedance
TB2904HQ(o)
2004-03-26