A Single-Switch High-Voltage Lamp Tester for Cold Cathode Fluorescent Lamps

This paper proposes a novel high-voltage generator served as a lamp tester for cold cathode fluorescent lamps (CCFLs). The proposed circuit consists of a buck-boost converter, an LC resonant network, and a step-up transformer. Only one active switch with simple control for turning on and off the switch at a high frequency is used. The proposed circuit has the advantage of simple configuration, small volume, and low cost. Besides, a high power factor at the ac line source can be obtained by operating the buck-boost converter at discontinuous conduction mode. A prototype circuit was built for testing 19-in CCFLs. It has proved that the proposed lamp tester can test the CCFLs quickly and effectively. Moreover, a test system is set up for obtaining the optical spectrum and the colorimetric values of CCFLs. By comparing the optical spectrum and colorimetric values of the test CCFL with the ones of the normal CCFL, light quality can be easily diagnosed. It provides an effective method to find out the possible defects in the manufacture process.