Discharge Tube Drive Circuit

Abstract

A discharge tube drive circuit for driving a plurality of discharge tubes is proposed with reduced number of parts and in a down-sized form. A first balance transformer is provided in a first drive circuit block, and a plurality of primary coils of a plurality of drive transformers in the first drive circuit block and a secondary coil of the first balance transformer are connected in series. A second balance transformer is provided in a second drive circuit block, and a plurality of primary coils of a plurality of drive transformers in the second drive circuit block and a secondary coil of the second balance transformer are connected in series. Further, a primary coil of the balance transformer and a primary coil of the second balance transformer are connected in series to configure the discharge tube drive circuit of the present invention.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 shows a circuit diagram of a discharge tube drive circuit according to a first embodiment of the present invention;

FIG. 2 shows a circuit diagram of a discharge tube drive circuit according to a second embodiment of the present invention;

FIG. 3 shows a circuit diagram of a discharge tube drive circuit according to a third embodiment of the present invention;

FIG. 4 shows a circuit diagram of a discharge tube drive circuit according to a forth embodiment of the present invention;

FIG. 5 shows a circuit diagram of a discharge tube drive circuit according to a fifth embodiment of the present invention;

FIG. 6 shows a circuit diagram of a discharge tube drive circuit according to a sixth embodiment of the present invention;

FIG. 7 shows a circuit diagram of a discharge tube drive circuit according to a seventh embodiment of the present invention; and

FIG. 8 shows a circuit diagram of a modified discharge tube drive circuit of each embodiment including drive circuit section having available drive transistors of the preceding embodiments according to the other embodiment of the present invention.

Claims

1. A discharge tube drive circuit comprising: a first and a second drive circuit blocks each having a plurality of drive transformers;a plurality of switches for generating high frequency signals; anda control unit for controlling said plurality of switches, whereinsaid first drive circuit block includes a first balance transformer; whereina plurality of primary coils of the plurality of drive transformers in the first drive circuit block and a secondary coil of the first balance transformer are connected in series;said second drive circuit block includes a second balance transformer;a plurality of primary coils of the plurality of drive transformers in said second drive circuit block and a secondary coil of the second balance transformer are connected in series; andsaid primary coil of the first balance transformer and the primary coil of the second balance transformer are connected in series.

2. A discharge tube drive circuit including a plurality of drive transformers for driving a plurality of discharge tubes comprising: at least two drive circuit blocks being formed by dividing said plurality of drive transformers, and including a balance transformer, respectively, whereinprimary coils of the drive transformer are connected in series to a secondary coil of the balance transformer in each of said drive circuit blocks; andone of terminals of a primary coil of the balance transformer is connected to an output terminal of an inverter including a plurality of switches in each of said drive circuit blocks.

3. The discharge tube drive circuit according to claim 1, wherein said balance transformer is configured to have a primary and a secondary coils having a turn ratio of 1:N (N is a positive integer).

4. The discharge tube drive circuit according to claim 3, wherein (N-1) balance transformers are provided with regard to the primary coils of the series-connected N drive transformers in each of said drive circuit blocks.

5. A discharge tube drive circuit for driving a LCD panel having a plurality of discharge tubes comprising: a plurality of drive circuit blocks for lighting said plurality of discharge tubes, whereineach of said plurality of drive circuit blocks includes a plurality of drive transformers in which primary coils of the drive transformers are connected in series; andeach of said plurality of drive circuit blocks includes a balance transformer in which a secondary coil of the balance transformer and the primary coils of the drive transformers are connected in series in order to conform currents flowing through said each of the drive circuit blocks.

6. A discharge tube drive circuit for lighting a plurality of discharge tubes comprising: a plurality of drive circuit blocks, whereineach of said drive circuit blocks includes a plurality of drive transformers; andprimary coils of the drive transformers are connected in series.

7. The discharge tube drive circuit according to claim 5, wherein said balance transformer is configured to have a primary and a secondary coils having a turn ratio of 1:N (N is a positive integer).

8. The discharge tube drive circuit according to claim 7, wherein (N-1) balance transformers are provided with regard to the primary coils of the series-connected N drive transformers in each of said drive circuit blocks.

9. The discharge tube drive circuit according to claim 2, wherein said balance transformer is configured to have a primary and a secondary coils having a turn ratio of 1:N (N is a positive integer).

10. The discharge tube drive circuit according to claim 9, wherein (N-1) balance transformers are provided with regard to the primary coils of the series-connected N drive transformers in each of said drive circuit blocks.