Application Design Center - LCD Projector

Circuit Protection of Light Bulb Switching Circuit

Solutions

• XT350A
• XT600A
• XT800A

Design Notes:

Protection Application:

The light bulb switching circuit controls the action of high-intensity bulb that provides light for the projector. Energy stored in the capacitor (C2) flows through the step-up transformer and ignites the bulb after the GDT fires (breaks over).

Solution Description:

As shown at the left, a switching GDT should be used as the switching device for the circuit. It is selected based upon the breakover level that is required by the storage capacitor and step-up transformer.

Companion Solutions:

The AC mains that supply power to this circuit should also be considered for circuit protection needs (fuse, MOV).

Regulatory Issues:

Does not apply.

Unique Features:

Does not apply.

Application Warnings:

Does not apply.