Driving circuit of vacuum fluorescent display

A technology for driving circuits and displays, applied in static indicators, instruments, telephone communications, etc., can solve problems such as filament damage, increase the processing load of the external controller 40, etc., and achieve the effect of improving reliability

Inactive Publication Date: 2004-09-29
SANYO ELECTRIC CO LTD
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

However, this is also a factor that increases the processing load of the external controller 40
Furthermore, the external controller 40 has a problem in that due to an increase in its own processing load, it takes considerable time from the moment it detects the abnormal state of the filament pulse voltage to the moment it executes a predetermined response (for example, turning off the power supply of the filament drive circuit 110). long time, resulting in damage or ignition of the filament 11

Method used

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  • Driving circuit of vacuum fluorescent display
  • Driving circuit of vacuum fluorescent display
  • Driving circuit of vacuum fluorescent display

Examples

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no. 1 example

[0061] === Abnormal state detection unit ==

[0062] Reference Figure 4 The circuit structure of the abnormal state detection unit 213 as the first embodiment of the present invention will be described.

[0063] As shown in the figure, the abnormal state detection unit 213 has a pulse detection unit 80, a level detection unit 90, and a selection unit 100.

[0064] The pulse detection unit 80 detects that the level of the filament pulse voltage is fixed according to the number of pulses of the filament pulse voltage input from the DETIN terminal for each predetermined time period TP.

[0065]The level detection unit 90 detects that the level of the filament pulse voltage is fixed based on the level of the direct current (DC) rectified voltage generated by integrating the filament pulse voltage input from the DETIN terminal.

[0066] The level of the DC rectified voltage is set in a low range of about "5-20%" with respect to the duty ratio of the filament pulse voltage, because the...

no. 2 example

[0102] The VFD drive circuit 20 according to the second embodiment of the present invention controls the output of at least one of the segment driver 209, the grid driver 210, and the filament pulse control unit 212 according to the output of the abnormal state detection unit 213 (abnormal state detection signal), The driving of at least one of the segment electrode 13, the grid electrode 12, and the filament 11 is terminated.

[0103] The operations of the above-mentioned controlled segment driver 209, grid driver 210, and filament pulse control unit 212 will be described separately.

[0104] == Control of the output of the grid driver or segment driver ==

[0105] Reference Figure 7 , The operation of the segment driver 209 or the grid driver 210 based on the abnormal state detection signal (the output of the abnormal state detection unit 213) will be described. In the following description, the description of the grid driver 210 that performs the same operation as the segment ...

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Abstract

A driving circuit for a vacuum fluorescent display for pulse-driving a filament of the vacuum fluorescent display with a pulse voltage. The driving circuit comprises a detecting unit for detecting that the level of the pulse voltage is fixed, and outputs a detection signal indicative of the result of the detection. Preferably, the driving circuit comprises a control unit for controlling at least one output of the outputs of the filament driving unit, the grid driving unit and the segment driving unit in order to terminate the driving of at least one of the filament, the grid electrode and the segment electrode, based on the detection signal.

Description

[0001] Cross-references to related applications [0002] This application claims the priority rights of Japanese Patent Application Nos. 2003-86466 and 2003-86465 filed on March 26, 2003, the contents of which are incorporated herein by reference. Technical field [0003] The invention relates to a driving circuit of a vacuum fluorescent display. Background technique [0004] A vacuum fluorescent display (hereinafter, referred to as "VFD") is a self-luminous display device that is used to generate heat from a directly heated cathode called a filament by applying a voltage to it in a vacuum chamber to make the filament emit heat The grid electrode is used to accelerate the hot electrons, and the hot electrons collide with the fluorescent material on the anode (segment) electrode to emit light, thereby displaying a desired pattern. VFD has excellent characteristics in terms of visibility, multi-coloring, low operating voltage, reliability (environmental resistance), etc., and is use...

Claims

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Application Information

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Patent Type & Authority Applications(China)
IPC IPC(8): G09G3/30G09G3/22
CPCG09G2330/08G09G3/22H04M1/0214H04M1/0225
Inventor 新井启之茂木修治木村毅德永哲也
Owner SANYO ELECTRIC CO LTD
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