wherein switch circuit sc of half bridge or full bridge topology is provided on the switching electronic ballast circuit 100 and through the resonant circuit to produce alternate sine wave voltage of high frequency a transformer t 1 will convert the alternate sine wave voltage to the secondary of the transformer t 1 to output the alternate sine wave voltage with high frequency required by ccfl lamp 1 lampn in order to supply the energy to the ccfl 200 the ccfl abnormal detective circuit 201 detects abnormality of every ccfl lamp 1 lampn an impedance matching device at positive end 202 is utilized to balance current and an impedance matching device at negative end 203 can be provided on the circuit to balance current in order to balance the current of every ccfl lamp 1 lampn within a required range an adjusting and enabling control device 103 controls periodic operations of the switching electronic ballast circuit 100 via a low frequency adjustable signal lpwm such that the brightness and the timing and order of the operations of the ccfl lamp 1 lampn can be controlled the auxiliary power circuit 101 produces a stable voltage of direct current for providing the required power source to the ccfl abnormal detective circuit 201 fig3 indicates schematic view of the improved power supply circuit of a lcd panel in accordance with another preferred example of the present invention the ccfl abnormal detective circuit 201 of the circuit in fig3 replaces the diodes d 13 dn 3 of fig2 with transistors q 11 qn 1 to achieve the same effect when the output of the transformer t 1 is at the positive period voltage detective capacitors c 13 cn 3 operate equivalent functions as the above mentioned circuit in fig2.