Circuit Protection Design Considerations for LCD TV Power Supplies and I/O Ports:Advanced LCD technology has resulted in larger screens, wider
viewing angles, and higher-quality video images. However, as
LCD TV screens grow bigger, and brighter, they require more
power to operate, increasing the need for more robust and
reliable circuit protection techniques.
A variety of circuit protection devices can be used to help protect
the LCD screen from damage caused by excessive current or
voltage transients. Overcurrent protection may take the form of a
fuse or a resettable PPTC (polymeric positive temperature
coefficient) device. Deciding whether to specify a PPTC device or a
single-use fuse depends on the LCD design, the types of threats the
device may be exposed to, and the relevant safety requirements.
PPTC devices are commonly applied to circuits that experience
high inrush currents on startup. PPTC devices are resilient to inrush currents and help eliminate the nuisance of blown fuses. Fuses
are well suited to circuit designs where resettablity is not desirable, or where faults occur only in a system failure condition. They
are also a practical solution when soft-start circuitry is used to limit inrush current. Tyco Electronics provides both small form
factor PPTC devices and single-use chip fuses, to give designers an array of overcurrent protection solutions.Tyco Electronics also offers a broad range of overvoltage and ESD (electrostatic discharge) suppression devices, for a variety of
LCD TV applications, as described below.