Patent ID: 7227316
Filing Date: 2007-06-05
Classification: H05B

Abstract:
1. A measure device for cold cathode fluorescent lamps, said device comprises: a high frequency power source circuit utilising AC power source; a time delay circuit, wherein, when the electronic ballast is working stably, and the cold cathode fluorescent lamps are in full brightness and stable, there is a pause before determining the electronic ballast's “on”, “off” status, the functioning time thus deferred is contingent upon the number, characteristic and quality of a CCFL Cluster; a DC power source circuit, wherein the output terminal's DC voltage supplies the CCFL Cluster, the protect circuit, and the time delay circuit, or internal, external power supply from other independent system; the CCFL Cluster formed by joining multiple CCFL sets through parallel connection, each of said CCFL set comprising HF HV capacitor, cold cathode fluorescent lamp, measure resistor, limit current resistor and photocoupler primary, wherein the HV capacitor, cold cathode fluorescent lamp and measure resistor are serially connected, two terminals of the CCFL set are connected to HF HV terminal, while two terminals of the measure resistor are coupled in parallel connection with two terminals formed by serial connection of the limit current resistor and photocoupler LED terminal; and A protection circuit, wherein the photocoupler's two collect-emitter terminals are formed in serial connection to couple with the up and down limit comparators, so that when the up and down limit comparators send out signals, HF power source is cut off.