A light source driving device for driving a light source module (22), includes a power stage circuit (20), a transformer and resonance circuit (21), a current balancing circuit (23), a feedback control circuit (25) and an fault detecting circuit (24). The power stage circuit converts received signals to alternating current (AC) signals. The transformer and resonance circuit converts the AC signals to electrical signals. The current balancing circuit balances current flowing through the light source module. The fault detecting circuit comprises a plurality of inputs (a1), (a2n (n=1, 2, 3, . . . , n)) and an output (b1). One of inputs is connected to one input of the current balancing circuit, other inputs are connected to outputs of the current balancing circuit, and the output outputs a fault signal. The feedback control circuit is used for controlling output of the power stage circuit.