Patent ID: 7394212

Claim:
An inverter unit for use in a display panel module including a lamp, comprising: a converter for receiving at least one drive signal and outputting a duty voltage signal accordingly; a transformer, selectively coupled with the lamp, for receiving the duty voltage signal, wherein when the transformer is coupled with the lamp, the transformer outputs an output voltage to the lamp according to the duty voltage signal to light up the lamp; a feedback circuit for receiving a feedback signal from the lamp and outputting a feedback voltage signal accordingly; and an open lamp lock circuit, electrically coupled with the feedback circuit, for receiving a control signal and selectively receiving the feedback voltage signal to detect whether the lamp is coupled, and for selectively disabling the at least one drive signal according to the feedback voltage signal and the control signal, wherein the open lamp lock circuit comprises: at least a diode having a negative electrode and a positive electrode for receiving the at least one drive signal; and a comparator having an input end and an output end electrically coupled with the negative electrode of the at least one diode, wherein the input end of the comparator receives the control signal and either of the feedback voltage signal and a reference voltage signal, and the comparator outputs a comparison-outcome signal accordingly; wherein when the inverter unit is at an initial state, the comparison-outcome signal turns off the at least one diode for the at least one drive signal to be transmitted to the converter.