Patent ID: 7315136

Claim:
A protection apparatus used in a multi-lamp driving system comprising a driving apparatus for driving a plurality of lamps and a current balancer for balancing the current flowing through each of the lamps, the current balancer comprising a plurality of detection nodes, the protection apparatus comprising: at least a detecting unit comprising; a plurality of first impedance devices, a first end of each impedance device coupled with the corresponding detection node; and a second impedance unit coupled with a second end of each first impedance device, wherein a cross-voltage between a first end and a second end of the second impedance device is a sum of the voltage level of the detection nodes coupled with the first impedance devices; and a determining unit coupled with the second impedance device of the at least one determining unit; wherein the determining unit outputs a protection signal to disable the driving apparatus when the determining unit determines at least one lamp malfunctions according to the cross-voltage between the first end and the second end of the second impedance device of the at least one detection unit.