tb2959hq TOSHIBA Semiconductor CORPORATION, tb2959hq Datasheet - Page 23

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

19. Attention in Use
 Use an appropriate power supply fuse to ensure that a large current does not continuously flow in case of
 If your design includes an inductive load such as a motor coil, incorporate a protection circuit into the
 Use a stable power supply with ICs with built-in protection functions. If the power supply is unstable, the
 Carefully select external components (such as inputs and negative feedback capacitors) and load
 Over current Protection Circuit
 Thermal Shutdown Circuit
 Heat Radiation Design
 Installation to Heat Sink
over current and/or IC failure. The IC will fully break down when used under conditions that exceed its
absolute maximum ratings, when the wiring is routed improperly or when an abnormal pulse noise occurs
from the wiring or load, causing a large current to continuously flow and the breakdown can lead smoke
or ignition. To minimize the effects of the flow of a large current in case of breakdown, appropriate
settings, such as fuse capacity, fusing time and insertion circuit location, are required.
design to prevent device malfunction or breakdown caused by the current resulting from the inrush
current at power ON or the negative current resulting from the back electromotive force at power OFF. For
details on how to connect a protection circuit such as a current limiting resistor or back electromotive
force adsorption diode, refer to individual IC datasheets or the IC databook. IC breakdown may cause
injury, smoke or ignition.
protection function may not operate, causing IC breakdown. IC breakdown may cause injury, smoke or
ignition.
components (such as speakers), for example, power amp and regulator. If there is a large amount of
leakage current such as input or negative feedback condenser, the IC output DC voltage will increase. If
this output voltage is connected to a speaker with low input withstand voltage, overcurrent or IC failure
can cause smoke or ignition. (The over current can cause smoke or ignition from the IC itself.) In
particular, please pay attention when using a Bridge Tied Load (BTL) connection type IC that inputs
output DC voltage to a speaker directly.
Over current protection circuits (referred to as current limiter circuits) do not necessarily protect ICs under
all circumstances. If the Over current protection circuits operate against the over current, clear the over
current status immediately. Depending on the method of use and usage conditions, such as exceeding
absolute maximum ratings can cause the over current protection circuit to not operate properly or IC
breakdown before operation. In addition, depending on the method of use and usage conditions, if over
current continues to flow for a long time after operation, the IC may generate heat resulting in breakdown.
Thermal shutdown circuits do not necessarily protect ICs under all circumstances. If the Thermal
shutdown circuits operate against the over temperature, clear the heat generation status immediately.
Depending on the method of use and usage conditions, such as exceeding absolute maximum ratings
can cause the thermal shutdown circuit to not operate properly or IC breakdown before operation.
When using an IC with large current flow such as power amp, regulator or driver, please design the
device so that heat is appropriately radiated, not to exceed the specified junction temperature (Tj) at any
time and condition. These ICs generate heat even during normal use. An inadequate IC heat radiation
design can lead to decrease in IC life, deterioration of IC characteristics or IC breakdown. In addition,
please design the device taking into considerate the effect of IC heat radiation with peripheral
components.
Please install the power IC to the heat sink not to apply excessive mechanical stress to the IC. Excessive
mechanical stress can lead to package cracks, resulting in a reduction in reliability or breakdown of internal IC
chip. In addition, depending on the IC, the use of silicon rubber may be prohibited. Check whether the use of
silicon rubber is prohibited for the IC you intend to use, or not. For details of power IC heat radiation design and
heat sink installation, refer to individual technical datasheets or IC databooks.
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TB2959HQ
2011-11-08