Patent ID: 7830102

Claim:
A light source driving device for driving a plurality of light sources, comprising: a power stage circuit, for converting received signals to alternating current (AC) signals; a transformer and resonance circuit, connected between the power stage circuit and the light sources, for converting the AC signals to electrical signals adapted for driving the light sources; a current balancing circuit, connected to the light sources, for balancing currents flowing through the light sources; a fault detecting circuit comprising a plurality of inputs and an output, for detecting whether one or more of the light sources is faulty; wherein one input of the fault detecting circuit is connected to one input of the current balancing circuit, other inputs of the fault detecting circuit are connected to outputs of the current balancing circuit, and the output of the fault detecting circuit outputs an fault signal, wherein the fault detecting circuit comprising: a primary switching component comprising a base, a drain and a source, wherein the base of the primary switching component is electronically connected to one input of the fault detecting circuit, the drain of the primary switching component is connected to a power source, and the source of the primary switching component is defined as the output of the fault detecting circuit; a plurality of secondary switching components each comprising a base, a drain and a source, wherein each of the base of the secondary switching components is respectively connected to one of the other inputs of the fault detecting circuit, the source of a first one of the secondary switching components is grounded, the drain of the first one of the secondary switching components is connected to the source of a second one of the secondary switching components, and the drain of the last one of the secondary switching components is connected to the base of the primary switching component; a bias resistor, connected between the base of the primary switching component and the power source; and a capacitor, connected between the base of the primary switching component and the ground; and a feedback control circuit, connected between the fault detecting circuit, the current balancing circuit and the power stage circuit, for controlling output of the power stage circuit according to the currents flowing through the light sources and the fault signal.