tb2959hq TOSHIBA Semiconductor CORPORATION, tb2959hq Datasheet - Page 10

• Manufacturer Part Number: tb2959hq
• Description: Maximum Power 47w Btl  4-ch Audio Power Ic
• Manufacturer: TOSHIBA Semiconductor CORPORATION

11. Protection Functions
< Speaker damaging scenario >
GND, and out to out short circuit protections.
(1)
(2)
(3)
(4)
A DC current of over 4 V is applied to the speaker due to an external circuit failure (Note 6).
(Abnormal DC output offset)
The speaker impedance becomes 1  or less due to a layer short.
A current of over 4 A flows into the speaker, damaging the speaker.
This product has internal protection circuits such as thermal shut down, over-voltage, out to V
When the DC resistance between the OUT and OUT pins falls below 1 , the output current exceeds
4 A. At this time, the protection circuit is activated to limit the current draw into the speaker.
This feature prevents the speaker from being damaged, as follows:
Thermal shut down
Over-voltage
It operates when voltage exceeding operating range is supplied to V
return automatically. When it operates, output bias is turned off and an output is intercepted.
Short to V
It operates when each pin is in irregular connection. If irregular connection is canceled, it will return
automatically.
Short circuit protection can operate for each channel.
When it operates, output bias of corresponding output is turned off and an output is intercepted.
Example) If channel 1 output shorts, channel 1 is protected but other channels 2 to 4 are available.
Prevention of speaker damage (in case of a layer short-circuit of the speaker)
It operates when junction temperature exceeds 150°C (typ.).
When it operates, it is protected in the following order.
1.
2.
3.
In any case if temperature falls, it will return automatically.


All outputs become in a mute state, when temperature continues rising in spite of output
Shutdown function starts, when a temperature rise continues though all outputs are in a mute
An Attenuation of an output starts first and the amount of attenuation also increases according
attenuation.
to a temperature rising,
state.
CC
, Short to GND, Output to output short
10
CC
pin. If voltage falls, it will
TB2959HQ
2011-11-08
CC
, out to