Multi-lamp drive device

Abstract

A multi-lamp drive device comprises a transformer, a drive circuit and at least a balanced inductor. The magnetic core of the transformer has a first side column, a second side column and at least a central column. A primary coil and a secondary coil are wound around the first side column and the second side column, respectively. The drive circuit can output an excitation power source to the transformer for driving lamps to be on based on the energy conversion characteristic of the transformer. With the help of the central column, the transformer can guide the counter magnetic flux generated by the load current without interfering the power conversion action of the transformer. Moreover, heat generated by the transformer due to a too larger load current can be reduced, and the protection function for the transformer during short circuit can also be accomplished.

Description

FIELD OF THE INVENTION [0001] The present invention relates to a multi-lamp drive device and, more particularly, to a transformer used for driving cold cathode fluorescent lamps and a multi-lamp drive device having this kind of transformer. BACKGROUND OF THE INVENTION [0002] Cold cathode fluorescent lamps (CCFLs) are used as the light source of a backlight system in an LCD panel. These CCFLs are driven by a drive circuit called an inverter. Because of technique progresses and consumer demands, the size of LCD panels increases continually. A single lamp can't meet the requirement for illumination of LCD panel. Two or more lamps are required instead. [0003] As shown in FIG. 1, a primary coil 42 and a secondary coil 43 are both wound around a central column 401 of a transformer 40 used in a conventional multi-lamp drive device. The primary coil 42 is connected with a drive circuit 47. When the drive circuit 47 generates an excitation power source, an excitation current will flow on the...

AI Technical Summary

Benefits of technology

This design effectively reduces heat and protects the transformer from short circuits, ensuring stable operation and preventing primary coil damage during load changes or secondary coil short circuits.

Problems solved by technology

Because of technique progresses and consumer demands, the size of LCD panels increases continually.

A single lamp can't meet the requirement for illumination of LCD panel.

Along with increase of the number of lamps, the required power rises to increase burdens to the drive circuit and the transformer.

Moreover, because the primary coil is subject to the interference from the secondary coil, normal function of the transformer will be affected.

If the secondary coil of the transformer is short circuited due to some factors, the primary coil will be burned out due to a very large counter magnetomotive force induced by the short-circuit current.

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