Circuit protection for LCD-TV backlighting, supplies - Electronic Products

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 voltage and current 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 polymeric positive temperature coefficient (PPTC) device. Deciding whether to specify a PPTC device or a single-use fuse depends on the LCD design and the types of threats the device may face.

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 resettability 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.

To enhance equipment safety and reliability, a variety of overvoltage protection devices including metal oxide varistors (MOVs), multilayer varistors (MLVs) and electrostatic discharge (ESD) surge protection devices can be used in a coordinated scheme with overcurrent protection devices, as discussed here.

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