KR100796650B1 - A Device of vacuum fluorescent display and its driving circuit - Google Patents

Abstract

The present invention relates to a vacuum fluorescent display device and a driving circuit thereof.

In the present invention, a predetermined number of diodes for reducing the predetermined external voltage applied from the outside to adjust the appropriate filament supply voltage of the vacuum fluorescent display device; A DC / DC converter converting an external voltage into a driving DC voltage; An inductor for storing and applying energy having a predetermined magnitude input from the outside through switching of the DC / DC converter; A frequency adjusting capacitor for controlling the switching speed of the DC / DC converter; A rectifier diode for rectifying the voltage output from the inductor and the DC / DC converter; A predetermined number of resistors for varying a voltage output from the rectifying diode to an appropriate driving voltage of the vacuum fluorescent display and the driving circuit thereof; And a predetermined number of capacitors for stabilizing an external voltage and a driving voltage. This results in cost savings and productivity improvements due to a reduction in total volume, material costs and component count.

Vacuum Fluorescent Display, Driving Circuit, Transformerless, DC / DC Converter, One-chip IC.

Description

A device of vacuum fluorescent display and its driving circuit

1 is a schematic configuration diagram of a vacuum fluorescent display device according to the prior art;

2 is a detailed power circuit diagram of a vacuum fluorescent display device according to the prior art;

3 is a block diagram of a vacuum fluorescent display device according to an embodiment of the present invention;

4 is a detailed circuit diagram of a vacuum fluorescent display device (excluding a driver) according to an exemplary embodiment of the present invention.

※ Explanation of code for main part of drawing ※

1: VFD power supply

2: VFD drive driver

3: Vacuum Fluorescent Display

10: DC / DC converter

12: diode

20: VFD drive module

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a vacuum fluorescent display and a driving circuit thereof, and more particularly, to a vacuum fluorescent display and a driving circuit for supplying driving power to a vacuum fluorescent display module for driving a vacuum fluorescent display. .

Vacuum Fluorescent Display (Vacuum Fluorescent Display) is a self-light emitting device that displays a variety of colored letters, symbols and figures using the phosphor by selectively colliding electrons emitted from the filament to the fluorescent layer under the control of the grid electrode and the anode electrode As a multi-color display is possible and low voltage driving is possible, it is easy to apply a semiconductor component and has high reliability, so it is used for various purposes in various fields.

The vacuum fluorescent display for supplying driving power to the vacuum fluorescent display module for driving the vacuum fluorescent display device is as follows.

FIG. 1 is a schematic configuration diagram of a vacuum fluorescent display device according to the related art. Referring to FIG. 1, a vacuum fluorescent display device includes a power supply unit 1, a driving driver 2, and a vacuum fluorescent display unit 3. The modules form a structure formed by being placed independently of each other.

The power supply unit 1 generates the power supply Ef for supplying the filament which is the cathode source of the vacuum fluorescent display unit 3 and the power supply VH for the drive driver 2 to generate the vacuum fluorescent display unit 3 and the drive driver 2. Will be printed respectively.

The driving driver 2 generates a voltage for driving the pattern in the vacuum fluorescent display 3 using the voltage applied from the power supply 1 and outputs the voltage to the vacuum fluorescent display 3.                         

The detailed configuration and operation process of the vacuum fluorescent display device having the above structure are as follows.

2 is a detailed power circuit diagram of a vacuum fluorescent display device according to the related art. Referring to FIG. 2, a power supply circuit of a conventional vacuum fluorescent display device has a transistor in which an input voltage Vcc is connected to a smoothing circuit C1 (C2), a starting resistor R1, and a speed-up diode D1 (D2). Q2) and (Q1) are connected to the primary winding NP of the transformer T / F1, and the secondary terminal of the transformer T / F1 is applied to the voltage terminal EF1 applied to the filament of the vacuum fluorescent display device. (EF2), a diode (D3), a capacitor (C3) (C4), a resistor (R2) (R3), a zener diode (ZD1) for determining the base level of the transistor (Q2); A half-wave rectifier circuit comprising a diode D4 and a capacitor C5 and C6 for generating a voltage applied to the grid and the anode of the vacuum fluorescent display; A constant voltage circuit composed of a resistor R5, a capacitor C5, and a zener diode ZD2 for moving the cathode potential of the vacuum fluorescent display device by the zener diode potential is connected.

In the power supply circuit of the conventional vacuum fluorescent display device configured as described above, the input voltage VCC flows to the base of the transistor Q2 through the smoothing capacitor C1 and C2 and the starting resistor R1 to conduct the transistor Q2. Let's go.

Therefore, the current flowing out from the emitter of transistor Q2 is applied to the base terminal of transistor Q1 to conduct the transistor Q1. At this time, the transistors Q2 and Q1 are used as relatively high power transistors by Darlington connection.

Therefore, since the current flows in the primary winding line NP of the transformer form T / F1 due to the conduction of the transistor Q1, the voltage V1 is generated, and the generated voltage is formed in the transformer form T / F1. Since the voltage is generated by being induced in the secondary winding Ns (Nb) of the transistor, the transistors Q2 and Q1 become conductive again by the voltage generated in the secondary winding Nb.

By performing such a series of operations repeatedly, the voltage VBB applied to the grid and the anode of the vacuum fluorescent display device and the filament of the vacuum fluorescent display device are applied from the secondary side of the transformo T / F1. The EF voltages F1 and F2 are output.

As shown in FIGS. 1 and 2, the power supply circuit in the vacuum fluorescent display device which performs such a structure (a structure including a transformer) and an operation process is scattered with a large number of other circuit components including a transformer. Not only increases the area of the substrate but also raises manufacturing costs and decreases productivity.

In addition, the power supply unit including the transformer (1 in FIG. 1) and the driving driver for the vacuum fluorescent display device (2 in FIG. 2) are formed independently of each other, thereby causing problems such as an increase in the total area.

SUMMARY OF THE INVENTION The present invention has been made to solve the above problems, and is formed such that a power supply unit including a DC / DC converter IC, not a transformer, and a driving driver for a vacuum fluorescent display device are integrated on a single chip. A vacuum fluorescent display device and a driving circuit thereof are provided.                         

The present invention also provides a vacuum fluorescent display device and a driving circuit thereof that occupy a small area as well as productivity improvement and material cost reduction due to a reduction in the number of parts.

The driving circuit of the vacuum fluorescent display device for achieving the above object,

A predetermined number of diodes for reducing a predetermined external voltage applied from the outside to adjust an appropriate filament supply voltage of the vacuum fluorescent display device;

A DC / DC converter converting the external voltage into a driving DC voltage;

An inductor storing and applying energy having a predetermined magnitude input from the outside through switching of the DC / DC converter;

A frequency adjusting capacitor controlling the switching speed of the DC / DC converter;

A rectifier diode for rectifying the voltage output from the inductor and the DC / DC converter;

A predetermined number of resistors for varying a voltage output from the rectifying diode to an appropriate driving voltage of the vacuum fluorescent display and its driving circuit; And

A predetermined number of capacitors to stabilize the external voltage and the driving voltage

Characterized in that it comprises a.

Vacuum fluorescent display device according to another aspect of the present invention,

A vacuum fluorescent indicator for selectively colliding the electrons emitted from the filament with the fluorescent layer under the control of the grid electrode and the anode electrode to display various colored letters, symbols, and figures using the phosphor;

A driving voltage generator including a conversion switching element for converting a predetermined external voltage applied from the outside to generate a predetermined driving voltage for driving the vacuum fluorescent indicator; And

A driving driver that outputs a pattern driving signal applied from the outside to the vacuum fluorescent indicator together with the driving voltage applied from the driving voltage generator.

Including;

The driving voltage generator and the driving driver are formed to be integrated into a single chip.

A predetermined number of diodes for reducing a predetermined external voltage applied from the outside to adjust an appropriate filament supply voltage of a vacuum fluorescent display device and a driving circuit thereof;

A DC / DC converter converting the external voltage into a driving DC voltage;

An inductor for storing and applying the external voltage through switching of the DC / DC converter;

A frequency adjusting capacitor controlling the switching speed of the DC / DC converter;

A rectifier diode for rectifying the voltage output from the inductor and the DC / DC converter;

A predetermined number of resistors for varying a voltage output from the rectifying diode to an appropriate driving voltage of the vacuum fluorescent display and its driving circuit; And

A predetermined number of capacitors to stabilize the external voltage and the driving voltage                     

Characterized in that it comprises a.

Hereinafter, a vacuum fluorescent display device and a driving circuit thereof according to an embodiment of the present invention will be described in detail with reference to the accompanying drawings.

3 is a block diagram illustrating a vacuum fluorescent display device according to an exemplary embodiment of the present invention.

Referring to FIG. 3, the VFD driving module 20 of the vacuum fluorescent display device includes a DC / DC converter 10, an N-bit driving driver 2, and a vacuum fluorescent display 3, and the N-bit driving driver. (2) includes an N-bit shift register (4), a latch (5), a gate array (6), wherein the DC / DC converter 10 and the N-bit drive driver 2 are integrated. It forms a structure formed on a single chip.

The DC / DC converter 10 performs duty and frequency control of the external power sources Vcc and 11 applied from the outside through the switching operation of the IC. The DC / DC converter 10 controls the external power source by the vacuum fluorescent display unit. 3) It converts into DC voltage (VH) which drives and outputs it.

The N-bit driving driver 2 converts the DC voltage applied from the DC / DC converter 10 into an appropriate voltage for driving the vacuum fluorescent display 3, or outputs the various patterns in the vacuum fluorescent display 3. Signals for controlling A1, A2, ..., An, G1, G2, ..., Gn) are externally applied and then sequentially output in proper combination.

The N-bit shift register 4 sequentially applies n-bit data and pattern driving signals applied from the outside.                     

When the predetermined pattern driving signal applied to the N-bit shift register 4 forms a predetermined bit, the latch 5 outputs the control signal according to a control signal (Enable, Clock, etc.) applied from the outside.

The gate array 6 outputs a predetermined combination of pattern driving signals of a predetermined bit output from the latch 5 through logic gates AND, NOR, and OR gates.

An operation process of the VFD driving module 20 in the vacuum fluorescent display device having the above structure is as follows.

First, when a predetermined voltage (approximately 5V to 12V, 11) is applied from the outside, the diode 12 connected to the external power input terminal is varied (reduced) to an appropriate voltage for driving the vacuum fluorescent display unit 3. To print.

In this case, the diode 12 reduces the voltage applied from the outside, and reduces the voltage of approximately 1V per diode. For this reason, the number of the diodes also varies according to the filament voltage Ef1 which varies according to the area and type of the vacuum fluorescent display unit 3 and the like.

On the other hand, the predetermined voltage applied from the outside is converted to the DC vacuum fluorescent display drive voltage (VH) through the DC / DC converter 10, and then the vacuum fluorescent display 3 via the N-bit drive driver (2) Is applied. At this time, the N-bit driving driver 2 converts the pattern driving signal applied from the outside appropriately and outputs it to the vacuum fluorescent display unit 3 according to a control signal (Enable, Clock, etc.) applied from the outside. .                     

As described above, the VFD driving module of the vacuum fluorescent display device according to the present invention is adapted to convert a predetermined external power supply Vcc applied from the outside into a predetermined appropriate voltage for driving the vacuum fluorescent display unit 3. A DC / DC converter IC is used instead of a transformer, and the DC / DC converter 10 and the N-Bit driver 12 are formed to be integrated in a single chip.

The VFD driving module 20 excluding the N-Bit driving driver in the vacuum fluorescent display device performing the structure and operation process will be described in detail as follows.

4 is a detailed circuit diagram of a vacuum fluorescent display device and a driving circuit thereof (except a driving driver) according to an exemplary embodiment of the present invention.

Referring to FIG. 4, a power supply device for applying a predetermined driving voltage to the vacuum fluorescent display unit 3 includes peripheral elements connected to a DC-DC converter and a DC-DC converter, and among the peripheral elements, a diode D2 is represented. The external voltage Vcc applied from the outside is decompressed, and the two resistors R1 and R2 are changed by the variable characteristics (type, size, etc.) of the driving voltage VH for driving the vacuum fluorescent display 3. Voltage, etc., the switching waveform of the DC-DC converter changes the voltage rectified via the diode D1 to an appropriate driving voltage VH, and the capacitor C3 controls the switching speed of the DC-DC converter. Frequency control is performed for the capacitors, and the capacitors C2 and C1 perform stabilization of the external voltage and stabilization of the driving voltage.

The operation process of the power supply device having the above structure is as follows.

First, a predetermined external voltage Vcc (approximately 5V to 12V) applied from the outside is changed to an appropriate voltage Ef1 for driving the vacuum fluorescent display unit 3 through a diode D2 connected to an external power input terminal. After (reduction), it is applied to the filament power source Ef1 of the vacuum fluorescent display unit 3.

On the other hand, the input energy of the external voltage is stored in the inductor (L1) and converted into a drive voltage for driving the vacuum fluorescent display unit 3 through the rectifying diode (D1) through the switching action of the DC / DC converter Is applied to the vacuum fluorescent display 3. In this case, the switching speed of the DC / DC converter is controlled by the control frequency of the capacitor C3, and the driving voltage is changed by two resistors R1 and R2 connected to the DC / DC converter. do. That is, the driving voltage is controlled by feedback control by the two resistors R1 and R2 because the driving voltage is variable according to the type, size, etc. of the vacuum fluorescent display.

That is, the two resistors R1 and R2 adjust the output voltage VH through a relational expression such as a driving voltage VH = reference voltage × {1+ (R2 / R1)} of the DC / DC converter IC.

As described above, the vacuum fluorescent display device according to the present invention uses a DC / DC converter IC formed to be integrated with a single driver and a single chip, and a plurality of various patterns using a predetermined number of peripheral elements connected to the DC / DC converter IC. The driving voltage VH and the filament-side power supply Ef are supplied to the vacuum fluorescent display module for emitting light.

Although the above has been described with reference to a preferred embodiment of the present invention, those skilled in the art will be able to variously modify and change the present invention without departing from the spirit and scope of the invention as set forth in the claims below. It will be appreciated.

According to the present invention described above, by reducing the number of peripheral devices by using a DC / DC converter IC instead of the transformer and the power supply unit for supplying power for driving the vacuum fluorescent display module to control the transformer, It is possible to improve productivity including the reduction of material cost and the number of parts, and to drive the VFD to the one-chip IC module by integrating the power supply unit with the driver IC for driving. It has an effect.

Claims (6)

A predetermined number of diodes connected to the external voltage and the vacuum fluorescent display to regulate an appropriate filament supply voltage of a vacuum fluorescent display by reducing a predetermined external voltage applied from the outside; A DC / DC converter having a first stage connected to the external voltage to convert the external voltage into a DC voltage for driving; A first stage is connected to the external voltage and a second stage is connected to a second stage of the DC / DC converter to store and apply energy of a predetermined magnitude input from the outside through switching of the DC / DC converter. Inductors; A frequency adjusting capacitor connected to a second end of the DC / DC converter to control a switching speed of the DC / DC converter; A rectifying diode connected to a second end of the inductor and a second end of the DC / DC converter to rectify a voltage output from the inductor and the DC / DC converter; A predetermined number of resistors connected between the first stage of the DC / DC converter and the rectifying diode to vary a voltage output from the rectifying diode to an appropriate driving voltage of the vacuum fluorescent display and its driving circuit; And A predetermined number of capacitors connected between the external voltage and the vacuum fluorescent display to stabilize the external voltage and the driving voltage The driving circuit of the vacuum fluorescent display device comprising a. A vacuum fluorescent indicator for selectively colliding the electrons emitted from the filament with the fluorescent layer under the control of the grid electrode and the anode electrode to display various colored letters, symbols, and figures using the phosphor; A driving voltage generator including a conversion switching element for converting a predetermined external voltage applied from the outside to generate a predetermined driving voltage for driving the vacuum fluorescent indicator; And A driving driver that outputs a pattern driving signal applied from the outside to the vacuum fluorescent indicator together with the driving voltage applied from the driving voltage generator. Including; And the driving voltage generator and the driving driver are integrated in a single chip. The method of claim 2, The conversion switching device, A vacuum fluorescent display device comprising a DC / DC converter IC. The method according to claim 2 or 3, The driving voltage generator, A predetermined number of diodes configured to reduce the predetermined external voltage applied from the outside to adjust to an appropriate filament supply voltage of the vacuum fluorescent display; An inductor storing energy of a predetermined external voltage applied from the outside and transmitting the external voltage through switching of the DC / DC converter; A frequency adjusting capacitor controlling the switching speed of the DC / DC converter; A rectifier diode for rectifying the voltage output from the inductor and the DC / DC converter into a DC voltage; A predetermined number of resistors varying a DC voltage output from the rectifying diode to a driving voltage of an appropriate level; And A predetermined number of capacitors to stabilize the external voltage and the driving voltage Vacuum fluorescent display device comprising a. The method of claim 4, wherein The predetermined number of resistors include first and second resistors, and a relationship between the first resistor, the second resistor, and the driving voltage is Drive voltage = DC / DC converter IC The reference voltage x {1+ (2nd resistance / 1st resistance)} is followed, The vacuum fluorescent display device characterized by the above-mentioned. The method according to claim 2 or 3, The drive driver, A shift register sequentially applying pattern driving signals of a predetermined bit applied from the outside; A latch for applying the pattern driving signal according to a control signal (Data_IN, Clock, etc.) applied from the outside when the pattern driving signal applied to the shift register satisfies a predetermined bit; And A gate array for properly combining the pattern driving signal applied from the latch using a logic gate, and then outputting the driving signal output from the DC / DC converter to the vacuum fluorescent indicator. Vacuum fluorescent display device comprising a.

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