TC62D722CFNG Datasheet, PDF (42/43 Pages) Toshiba Semiconductor – 16-Output constant current LED driver with the output gain control function and the PWM grayscale function

TC62D722CFG/CFNG
IC Usage Considerations
Notes on handling of ICs
[1] The absolute maximum ratings of a semiconductor device are a set of ratings that must not be exceeded,
even for a moment. Do not exceed any of these ratings.
Exceeding the rating(s) may cause the device breakdown, damage or deterioration, and may result injury
by explosion or combustion.
[2] Use an appropriate power supply fuse to ensure that a large current does not continuously flow in case of
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.
[3] If your design includes an inductive load such as a motor coil, incorporate a protection circuit into the
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. IC
breakdown may cause injury, smoke or ignition.
Use a stable power supply with ICs with built-in protection functions. If the power supply is unstable, the
protection function may not operate, causing IC breakdown. IC breakdown may cause injury, smoke or
ignition.
[4] Do not insert devices in the wrong orientation or incorrectly.
Make sure that the positive and negative terminals of power supplies are connected properly.
Otherwise, the current or power consumption may exceed the absolute maximum rating, and exceeding
the rating(s) may cause the device breakdown, damage or deterioration, and may result injury by
explosion or combustion.
In addition, do not use any device that is applied the current with inserting in the wrong orientation or
incorrectly even just one time.
[5] Carefully select external components (such as inputs and negative feedback capacitors) and load
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.
Points to remember on handling of ICs
(1) Heat Radiation Design
In 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 (T_J) 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.
(2) Back-EMF
When a motor rotates in the reverse direction, stops or slows down abruptly, a current flow back to the
motor’s power supply due to the effect of back-EMF. If the current sink capability of the power supply is
small, the device’s motor power supply and output pins might be exposed to conditions beyond
maximum ratings. To avoid this problem, take the effect of back-EMF into consideration in system design.
(3) Thermal Shutdown Circuit
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.
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2011-09-24