JP2000003222A - Power supply and information display device - Google Patents

Abstract

(57) [Problem] To provide a power supply device which is simple and extremely stable in power supply, and in which circuit damage to an external device hardly occurs due to careless high voltage output. Further, a display device including the power supply device is obtained. A low-voltage power supply for generating a low voltage for output to an external device, a coil connected in series to the low-voltage power supply, and a magnetic field generated by a current flowing through the coil are electrically detected. A magnetic element such as a Hall element, and a high-voltage power supply for generating a high voltage for output to an external device.The low-voltage power supply outputs a predetermined low voltage to the external device. After the detection, the high voltage power supply unit outputs a high voltage to the external device.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a power supply device which is simple, highly safe and has stable voltage characteristics, and an information display device such as a PDP (Plasma Display Panel) provided with the power supply device.

[0002]

2. Description of the Related Art In recent years, thin and lightweight liquid crystal display devices and plasma display devices have been put into practical use as information display devices replacing color CRTs. In these thin display devices, a display device portion such as a display panel and a power supply device portion for supplying power are often separated in order to maximize the feature of the thin display device. Hereinafter, a conventional information display device will be described using a plasma display as an example.

FIG. 7 is a view for explaining a conventional plasma display disclosed in Japanese Patent Application Laid-Open No. 8-314407. 7, reference numeral 36 denotes a display unit, 37 denotes a display panel, 38 denotes a power supply unit, 39 denotes a low-voltage power supply, 40 denotes a delay circuit, 41 denotes a high-voltage power supply, 42 denotes a low-voltage cable,
43 is a feedback cable, 44 is a high-voltage cable, 45 is G
An ND (ground potential) cable 46 is a connection terminal. Reference numeral 29 denotes a large-capacity capacitor, which will be described in detail later.
The low-voltage cable 42, the feedback cable 43, and the high-voltage cable 44 are often long cables, for example, 3 m to 10 m.
2 is composed of 2 to 3 pairs of wires and 1 to 2 pairs of wires for the high-voltage cable 44 to prevent a voltage drop.

Next, the operation of the plasma display of FIG. 7 will be described. When a switch (not shown) is turned on,
The low voltage Vcc is output from the low voltage power supply unit 39 of the power supply unit 38 to the display unit 36 via the low voltage cable 42. The display device unit 36 uses this low voltage to initialize a predetermined circuit such as a drive circuit (panel drive circuit) for driving the display panel 37 included in the display device unit 36 and to connect the feedback cable 43 The feedback voltage Vr is output to the power supply unit 38 via the power supply unit 38. After receiving the feedback voltage Vr, the power supply unit 38 supplies a high voltage Vs from the high voltage power supply unit 41 to the display unit 36 via the high voltage cable 44 after a predetermined delay time in the delay circuit 40. Output. Upon receiving the high voltage Vs, the display panel 37 of the display unit 36 starts the display operation.

As described above, the power supply unit 38 of the conventional plasma display is configured such that “the low voltage Vcc
"Receiving a signal indicating that the low voltage Vcc has been supplied normally from the display unit 36", "Display unit 36"
Have sequentially performed operations such as waiting for a period of time sufficient to end predetermined initialization at the low voltage Vcc (delay time) and "starting to supply the high voltage Vs to the display unit 36". This is to prevent the high voltage Vs from being applied when the display device section 36 has not been sufficiently initialized.

FIG. 8 is a view for explaining a plasma display disclosed in Japanese Patent Application Laid-Open No. 9-93804. 7 and 8 indicate the same or corresponding parts.

In FIG. 8, reference numeral 47 denotes a detection circuit, reference numeral 48 denotes a transistor, reference numeral 49 denotes a base of the transistor 48, reference numeral 50 denotes a collector of the transistor 48, and reference numeral 51 denotes a connection between the base 49 and a ground point 52 provided on the display unit 36. It is a relay cable for. The high-voltage power supply 41 has a collector 50
Is set to output a high voltage when the electric potential of 5 V is 5V.

Next, the operation of the plasma display of FIG. 8 will be described. When the relay cable 51 is not connected, the potential of the base 49 is 5V. Therefore, the transistor 48 is turned on, and the potential of the collector 50 becomes 0 V (substantially ground). Therefore, no high voltage is output from the high voltage power supply unit 41. On the other hand, when the relay cable 51 is connected, the potential of the base 49 is 0 V (substantially ground). Therefore, the transistor 48 is OFF and the potential of the collector 50 is 5V. Therefore, a high voltage is output from the high voltage power supply unit 41.

As described above, the power supply unit 38 of the conventional plasma display detects that the various cables are normally connected by the relay cable 51 and the detection circuit 47, and after the detection, sends a high signal to the display unit 36. It is configured to output a voltage.

[0010]

As described above, for example, a display device such as a plasma display, particularly a power supply device used for a type in which a power supply unit and a display unit are separated from each other, requires a sufficient setup. The configuration is such that a high voltage is not applied to the display device, and circuit breakage is unlikely to occur.

However, in the power supply device shown in FIG. 7 shown in Japanese Patent Application Laid-Open No. 8-314407, it is necessary to provide a dedicated line such as a feedback cable 43 for feeding back a low voltage, and the cable becomes thicker. When it became hard, there was a problem in its handling. Further, wiring and a circuit for adjusting the voltage of the feedback cable 43 must be provided on the display device section 36 side. Further, even if the connection of various cables could be confirmed, it was not possible to confirm whether the display device section 36 was operating normally (whether or not there was a failure).

Further, in a power supply device shown in FIG.
And the detection circuit 47 requires a resistor to be inserted directly into the output of the low-voltage power supply 39, so that the output impedance of the low-voltage power supply 39 increases. I will. For this reason, the load on the display device section 36 easily affects the output fluctuation of the low-voltage power supply section 39 as it is, causing a problem that power supply stability is deteriorated. Similarly, even if the connection of various cables could be confirmed, it was not possible to confirm whether the display device section 36 was operating normally.

Further, in an information display apparatus such as a plasma display, the display unit 36 is driven by a high-voltage pulse switching operation.
When the pulse rises and falls, a large charge / discharge current flows to the high-voltage power supply unit 41. Therefore, a large-capacity capacitor (for example, FIG.
And a capacitor 29) in FIG. 8 is generally inserted, but since the voltage is held at the added voltage value (that is, in this case, a high voltage), the power supply device The output terminal of the high-voltage power supply unit 41 remains at a high voltage for a certain period of time even after the power supply is turned off. If the high-voltage cable 44 is inserted or removed in such a state, a circuit such as a panel drive circuit included in the display unit 36 may be damaged.

The present invention has been made in order to solve the above-described problems in such a situation, and the safety of the present invention is such that the circuit of an external device is unlikely to be damaged by an inadvertent high-voltage output. An object is to obtain a high power supply device with a simple structure. Another object is to obtain a display device including the power supply device.

[0015]

A power supply device according to the present invention comprises: a low-voltage power supply for generating a low voltage for output to an external device; and a magnetic generating element connected in series to the low-voltage power supply. A magneto-electric element such as a Hall element for electrically detecting a magnetic field generated by a current flowing through the magnetism generating element, and a high-voltage power supply unit for generating a high voltage for output to the external device, The high-voltage power supply unit outputs a high voltage to the external device after the low-voltage power supply unit detects that the low-voltage power supply unit outputs a predetermined low voltage to the external device using the magnetoelectric element.

Further, the power supply device according to the present invention, after detecting that a predetermined low voltage is output from the low-voltage power supply unit to the external device, waits a while after the high-voltage power supply unit supplies the external device with a high voltage. A voltage is output.

In the power supply device according to the present invention, a diode having a forward direction from the external device toward the low-voltage power supply unit is connected in parallel to the magnetic field generating element.

Further, the power supply device according to the present invention comprises a low-voltage power supply for generating a low voltage, a high-voltage power supply for generating a high voltage, and an impedance connected between the high-voltage power supply and GND. A switching element that is turned off with a predetermined correlation with the output of the low-voltage power supply, and is turned on with a predetermined correlation with the output of the high-voltage power supply. is there.

The power supply device according to the present invention includes a low-voltage power supply unit for generating a low voltage for output to an external device;
A medium-voltage power supply for generating a medium voltage for output to the external device; and a high-voltage power supply for generating a high voltage for output to the external device, the low-voltage power supply and the medium-voltage power supply. Output a low voltage and a medium voltage to the external device, and receive a signal indicating that the external device operates normally by the low voltage and the medium voltage. This is to output a voltage.

Further, an information display device according to the present invention includes the power supply device and a display device driven by the power supply device.

[0021]

DESCRIPTION OF THE PREFERRED EMBODIMENTS Embodiment 1 FIG. 1 is a schematic configuration diagram illustrating a plasma display as an example of an information display device according to a first embodiment of the present invention. In the following description, the same reference numerals as those in the related art indicate the same or corresponding parts. In the figure, 1 is a power supply unit 38
A detecting unit for detecting that the display device unit 36 is normally connected and that a predetermined low voltage is normally output from the power supply unit 38 to the display device unit 36;
2 is a high-voltage power supply unit 4 based on the detection result of the detection unit 1 and the like.
1 is a power supply control circuit, 3 is a low-voltage load unit in the display unit 36, 4 is a high-voltage load unit, and 5 is a converter that converts video data input from the outside into predetermined data to perform various display controls. A drive control unit 6 is a high-voltage control unit that controls various drive units 8 to 10 described later, and 7 is a various drive unit 8 described later.
An internal power supply for supplying a predetermined voltage to the display panel 10, an X drive unit 8 for scanning the X electrodes of the display panel 37, a Y drive unit 9 for maintaining the display of the display panel 37, and a display panel 3
Reference numeral 45 denotes a GND (ground) cable which turns ON / OFF the W electrode 7 based on display data.

Next, the operation will be described. Hereinafter, the first power supply unit 38 and the display unit 36 are normally connected.
State, the power supply unit 38 and the display unit 36 are normally connected but the display unit 36 is not operating normally. The second state is that the power supply unit 38 and the display unit 36 are normal. The operation in the third state where no connection is made will be described sequentially.

(Explanation of First State) First, as shown in FIG. 1, the power supply unit 38 and the display unit 36 are normally connected by the low-voltage cable 42, the high-voltage cable 44, and the GND cable 45. The first state will be described. When a power supply (not shown) is turned on, a low voltage of, for example, about 5 V, which is mainly used for a logic power supply of a control system, is output from the low voltage power supply section 39, and the display device section is connected via the detection section 1 and the low voltage cable 42. It is supplied to 36 low voltage load units 3.
The low-voltage load unit 3 including the drive control unit 5 converts the video data input from the outside into a predetermined data format, initializes the drive control unit 5 that controls the display operation, and starts various controls. At this time, a logic part (not shown) of the high-voltage control unit 6 is also initialized. On the other hand, in the detection unit 1 connected in series to the low-voltage power supply unit 39, a current starts to flow at the same time as the low-voltage power supply unit 39 starts outputting a low voltage. The detection unit 1 outputs a detection signal 35 to the power supply control circuit 2 when the current value reaches a predetermined value. Upon receiving the detection signal 35, the power supply control circuit 2 controls the high voltage power supply 41 to start outputting a high voltage of, for example, about 150 to 200 V with a predetermined delay. The internal power supply 7 is approximately 150 to
A predetermined voltage is generated based on a high voltage output of 200 V and supplied to various circuits. For example, about 70 V is applied to the W drive unit 10 for driving the W electrode, and about 9 V is applied to the X drive unit 8 for scanning the X electrode.
0 V and about 300 V are supplied to the Y drive unit 9 for maintaining the display of the display panel 37 by generating an erase pulse. According to the above configuration, the display device section 36 receives a high voltage after the low voltage is input and the predetermined initialization of the low voltage load section 3 is completed, and the predetermined initialization is completed. Circuit breakage or the like due to high voltage being applied before can be prevented.

(Explanation of Second State) Next, the power supply unit 38 and the display unit 36 are normally connected by the low-voltage cable 42 and the like, but the display unit 36 is operating normally. A description will be given of a state where there is not. In this case, the current from the low-voltage power supply unit 39 is often lower or higher than when the display device unit 36 is operating normally. Therefore, based on the detected current value of the detection unit 1, the display unit 36
The output of the high voltage and / or the low voltage from the power supply unit 38 is stopped when the abnormality is detected. Thus, it is possible to prevent a higher voltage from being supplied to the display device unit 36 in the abnormal state, thereby preventing a further large failure from occurring. Further, a surge voltage is applied to the internal power supply 7 and the control system such as the high-voltage control unit 6 of the display device unit 36 when a large current temporarily flows through the display device unit 36, thereby preventing a failure such as circuit breakage. Can also be expected.

(Explanation of Third State) Next, the low voltage cable 42 and the like are connected to the power supply unit 38 or the display unit 36.
A third state in which no connection is made on the side or both sides will be described. In this case, the low voltage cable 42 or the GN
Since the D cable 45 is not connected, no current flows to the detection unit 1. Therefore, even if the power switch is ON, the high voltage power supply unit 41 does not operate because the detection unit 1 does not output the valid detection signal 35 (that is, the high voltage is not output). This guarantees security when the cable is not properly connected.

(Basic Circuit Configuration) FIG.
FIG. 3 is a diagram illustrating a basic circuit configuration of the detection unit 1 shown in FIG. In the following description, the same reference numerals as those described above indicate the same or corresponding parts. FIG. 2 (a)
In the figure, reference numeral 11 denotes the low-voltage power supply unit 39 shown in FIG.
2 is connected to the GND, 13 is connected to the low-voltage cable 42 via the connection terminal 46 shown in FIG. 1, and 14 is the GND cable 45 via the connection terminal 46 shown in FIG.
Connected to. Reference numeral 15 denotes a coil which is a magnetism generating element which is electrically connected to the low voltage power supply unit 39 shown in FIG. 1 so as to be in series. A diode for preventing an abnormal voltage from being generated in the power supply system, a Hall element 17 for electrically (here, a potential difference) detecting a magnetic field generated from the coil 15, and a potential difference 18 detected in the Hall element 17. An amplifier for amplification, 19 is a reference voltage source, 20 is a comparator for comparing the output voltage of the amplifier 18 with the reference voltage output from the reference voltage source 19, and 21 is ON / OFF according to the output voltage from the comparator 20. In addition, the collector 22 is connected to the power supply control circuit 2 shown in FIG. 1, and outputs a detection signal 35 as a detection output to the power supply control circuit 2, and 23 is a resistance element. . FIG. 3 is a connection diagram showing a circuit configuration when the detection unit 1 shown in FIG. 2 is incorporated in the power supply unit 38 shown in FIG.

FIG. 2B shows the coil 1 shown in FIG.
FIG. 5 is a diagram for explaining a magnetic field generated when a current flows through the reference numeral 5. Thus, the coil 15 forms a solenoid, and a magnetic field is formed by flowing an electric current. The magnitude of the magnetic field formed depends on the number of turns of the coil 15 and the coil 15
Is proportional to the magnitude of the current flowing through
And the direction of the flowing current.

FIG. 2C is a view for explaining the Hall element 17 shown in FIG. 2A. A to D in the figure are electrodes, and when a magnetic field (N → S direction in the figure) is applied in a state where a voltage E is applied between the electrode A and the electrode B in the configuration shown in the figure, the left hand of Fleming Voltage V is generated between electrode C and electrode D according to the law. Therefore, a change in the magnetic field outside the Hall element 17 can be taken out as a change in the voltage. In the first embodiment, the Hall element 17 having such characteristics is placed on the center line around which the coil 15 is wound, for example. , The magnitude and direction of the magnetic field generated by the coil 15 are detected by the magnitude and polarity of the voltage output from the Hall element 17, respectively.

(Explanation of Operation) Hereinafter, the operation of the detection unit 1 will be described with reference to FIG. Since the output (voltage V in FIG. 2C) generated in the above-described Hall element 17 is weak, the output is once amplified by the amplifier 18. The amplified output is compared with a reference voltage output from a reference voltage source 19 by a comparator 20, and the voltage from the comparator 20 is applied to a transistor 2 functioning as a switching element.
1 is input to the base (terminal). Therefore, the transistor 21 performs a switching operation of turning on or off according to the output of the comparator 20, and the voltage of the collector 22 changes with this switching operation. The voltage of the collector 22 is output to the power supply control circuit 2 as a detection signal 35.

Here, the case where the Hall element 17 is used has been described. However, an element capable of electrically detecting a magnetic field, that is, a so-called magneto-electric element is not limited to the Hall element 17 and may be the same as described above. Applicable to Other magneto-electric elements include, for example, a magneto-resistance element whose resistance changes according to a magnetic field, and a semiconductor element utilizing a photoelectromagnetic effect in which an electromotive force is generated when a magnetic field is applied in a state where the surface is irradiated with light. .

In this case, the detection signal 35 is applied to the collector 2 by using the comparator 20 and the transistor 21.
2 ON or OFF (this state is, for example, HIGH /
(It may correspond to the LOW potential). However, for example, transistor 2
If a plurality of 1s are used, or if an AD converter or various arithmetic units are used, a multi-valued detection signal 3 corresponding to more situations
5 can be obtained, and the power supply unit 38 and / or the display unit 36 can be controlled according to complicated control logic.

By adopting the configuration as described above, the detection unit 1 can detect the output state of the low-voltage power supply unit 39 without substantially affecting the output impedance of the low-voltage power supply unit 39 with respect to the DC component. Power supply device and an information display device provided with the power supply device. That is, the power supply unit 38 which can supply a stable voltage with respect to a load fluctuation having a low output impedance can be obtained, and the connection status, operation, failure, and the like of the display unit 36 can be detected, thereby improving reliability and safety. I do.

The power supply control circuit 2 controls the high voltage power supply section 41 based on the detection signal 35 of the detection section 1 so that after the predetermined initialization of the low voltage load section 3 by the input of the low voltage is completed, It is possible to perform control such as starting application of a high voltage, and to prevent occurrence of circuit breakage due to application of a high voltage before initialization. In addition, it is possible to improve safety when a cable is inserted or removed during use.

In addition, since the low voltage output can be monitored by the power supply unit 38 alone without providing a dedicated cable, a power supply unit and an information display device having a simple configuration and ensuring safety can be obtained. be able to.

The detection value (detection level) of the current flowing through the coil 15 can be changed by changing the reference voltage output from the reference voltage source 19 in FIG. Is easy. The coil 15
Although it is possible to increase the sensitivity of the detection unit 1 by increasing the number of turns, the wire length of the coil 15 increases when the number of turns increases, and the impedance of the coil 15 increases. Therefore, the low voltage cable 4
2 is composed of multiple pairs or multiple cables,
When the method of detecting the current flowing through a part of the plurality of pairs or the plurality of cables is adopted, the current flowing into the detection unit 1 is hardly distributed. In such a case, it is better to connect the detection unit 1 to each wiring of each cable constituting the low-voltage cable 42.

Furthermore, by inserting a diode 16 (sometimes called a fast recovery diode) connected in parallel with the coil 15, the coil 1
5, the occurrence of overvoltage and reverse voltage at the time of rise and fall of the power supply caused by the inductance can be suppressed,
Circuit protection can be provided. In particular, when the display element of the display panel 37 is a capacitive load such as an AC type plasma display and charge and discharge are repeated during high-voltage switching, the diode 16 is used.
(First recovery diode) has a great effect of circuit protection.

Embodiment 2 FIG. 4 is a diagram illustrating another power supply unit 38 according to the second embodiment of the present invention. In the following description, the same reference numerals as those described above indicate the same or corresponding parts. Further, description of the same parts as those in the first embodiment will be omitted.

In FIG. 4, 24 is a delay circuit, 25 is a transistor as a switching element, 26 is a load resistor, 27 is a high voltage output section of the high voltage power supply section 41, and 28 is a GND section (ground) of the high voltage power supply section 41. And a capacitor 29 connected to the high-voltage output unit 27. As described above, in the second embodiment, the high voltage output unit 27 and the GND
By providing a transistor 25 as a switching element between the unit 28 and the transistor 25 and turning on / off the transistor 25 in accordance with the output of the detection unit 1, it is possible to reliably and easily protect various circuits and prevent electric shock. It is what was constituted.

Hereinafter, the operation of the power supply unit 38 shown in FIG.
Will be described. Power supply unit 38 shown in FIG.
When the display unit 36 and the display unit 36 are normally connected to each other by the low-voltage cable 42 or the like, a high voltage is output to the display unit 36 basically in the following order. That is, when a low voltage is normally output from the low-voltage power supply unit 39, a predetermined current flows through the detection unit 1 as described above, and the detection unit 1 outputs the detection signal 35 to the power supply control circuit 2 (more specifically, Output to the delay circuit 40) and the delay circuit 24. The delay circuit 24 supplies an output obtained by delaying the detection signal 35 for a predetermined period to the base of the transistor 25, and thereby the transistor 2
5 is turned OFF, and the load resistor 26 is connected to the ground potential (GND unit 2).
8) Disconnect from Next, after a predetermined delay time (hereinafter referred to as a power-on delay time), the power supply control circuit 2 starts outputting a high voltage from the high voltage power supply unit 41.

On the other hand, when the power of the power supply unit 38 is turned off, it basically operates in the following order.
When the power is turned off, the high-voltage power supply unit 41 immediately stops the high-voltage output. However, at this point, the voltage due to the charge accumulated in the output capacitor 29 is still output. After the high-voltage output from the high-voltage power supply unit 4 is stopped, the delay circuit 24 turns on the transistor 25 after a predetermined time (hereinafter, referred to as a power-off delay time) to turn the load resistor 26 to the ground potential (GND). Section 28). Thus, the time (time constant) according to the resistance value of the load resistor 26 is obtained.
Then, the electric charge accumulated in the capacitor 29 is discharged, and the voltage (output) based on the electric charge accumulated in the capacitor 29 can be rapidly attenuated. The time required for discharging the capacitor 29, which is determined by the capacitor 29 and the load resistor 26 (a so-called CR circuit), is preferably a time constant of 1 second or less for safety. further,
It is preferable that the relationship between the power-on delay time and the power-off delay time is (power-on delay time) ≧ (power-off delay time). By doing so, even if the power supply unit 38 is repeatedly turned on and off, stable high-voltage output can be ensured, and unnecessary heat generation in the load resistor 26 can be suppressed.

By configuring the power supply unit 38 as described above, the electric power accumulated in the capacitor 29 provided at the output unit of the high voltage load unit 4 after the power supply unit 38 is turned off. An external device (for example, the display device unit 36 shown in FIG. 1) which can quickly lower the voltage value, for example, by connecting and disconnecting the high-voltage cable 44 immediately after the power supply unit 38 is turned off. Can be avoided, and safety against electric shock and the like can be extremely increased. Furthermore, a power supply device capable of performing a stable operation even when the power supply is repeatedly turned on and off can be obtained.

Embodiment 3 FIG. 5 is a diagram illustrating a plasma display as an example of an information display device according to a third embodiment of the present invention. In the following description, the same reference numerals as those described above indicate the same or corresponding parts. Further, description of the same parts as those in the first embodiment will be omitted.

In FIG. 5, 30 is, for example, about 10 to 30.
An operation confirmation power supply that outputs a medium voltage of about V, 31 is a resistor connected in series to the operation confirmation power supply 30, 32 is a diode for preventing reverse voltage, and 33 is a low voltage power supply and operation of various circuits. A detection circuit portion for detection, 34 is a confirmation cable for transmitting an electric signal corresponding to the detection result of the detection circuit portion 33 to the power supply device portion.

Next, the operation will be described. At power on,
The power supply unit 38 outputs a low voltage from the low-voltage power supply unit 39 and outputs a medium voltage of about 10 to 30 V from the operation confirmation power supply 30. The output of the medium voltage is supplied to the high voltage load unit 4 through the high voltage cable 44. The low voltage output from the low-voltage power supply unit 39 is supplied to the low-voltage load unit 3 through the low-voltage cable 42.

The detection circuit section 33 detects (confirms) that the low voltage output from the low voltage power supply section 39 is normally applied, and detects the high voltage load by the medium voltage output from the operation confirmation power supply 30. It is confirmed whether or not a predetermined operation (for example, switching) in the unit 4 can be normally performed, and as a result, an output (signal) is output to the power supply unit 38 via the confirmation cable 34. The power supply unit 38 receives this output, and starts a predetermined high voltage output from the high voltage power supply unit 41 when the predetermined operation in the high voltage load unit 4 is normal. The resistance 31 is used when the high voltage load unit 4 of the display unit 36 is in a low impedance state.
It functions as a protection resistor for protecting various circuits of the power supply unit 38. In the detection of the operation in the high voltage load unit 4, for example, an output (eg, shift data output from the IC) from the last circuit (eg, the scanning IC) is fed back to the detection circuit unit 33. Checking the operation of various switch circuits It is possible to detect most failures in the high-voltage load unit 4 by detecting the voltage output of the internal power supply 7 or the like.

According to the above configuration, the power supply unit 3
After detecting and confirming that the display device 8 and the display device unit 36 are normally connected by the low-voltage cable 42 and the high-voltage cable 44, the predetermined initialization of the low-voltage load unit 3 and the high-voltage load unit 4 is performed. Since the high voltage can be supplied to the high voltage load unit 4 after the termination, it is possible to prevent the high voltage from being applied before the high voltage load unit 4 is initialized. Breakage due to application of voltage can be avoided.

Further, since it is confirmed that the high-voltage load unit 4 operates normally (that is, there is no failure), a high voltage is supplied to the high-voltage load unit 4. It is possible to prevent a portion where a chain failure occurs due to application of a high voltage to the generated portion, and to obtain a safe and reliable power supply device and information display device.

Embodiment 4 FIG. 6 is a diagram illustrating a plasma display as an example of an information display device according to a fourth embodiment of the present invention. In the following description, the same reference numerals indicate the same or corresponding parts. In the present embodiment, the detection unit 1 shown in FIG. 1 and the operation confirmation power source 30, the resistor 31, the diode 32, and the like shown in FIG.
This is a combination of a detection circuit section 33, a confirmation cable 34, and the like.

Next, the operation will be described. Power supply unit 3
8 detects that the low-voltage power supply section 39 has output a low voltage normally, the operation confirmation power supply 30 outputs a medium voltage of about 10 to 30 V after a predetermined delay time. 36. This medium voltage (about 10-30
The display device section 36 supplied with V) confirms whether the high-voltage load section 4 operates normally using the supplied medium voltage, and the high-voltage load section 4 operates normally without any failure. This is detected by the detection circuit unit 33. When the high voltage load unit 4 operates normally and detects that there is no failure, the detection circuit unit 33 outputs a signal to that effect to the power supply unit 38.
The power supply unit 38 receives this signal and starts supplying a high voltage from the high voltage power supply unit 41.

According to the above configuration, the power supply unit 3
8. It is possible to reliably prevent various circuits such as the high-voltage load unit 4 from being damaged due to mishandling of various cables such as the display unit 36 and the high-voltage cable 44. Similarly, safety against electric shock and the like can be secured.

As described above, the plasma display as an example of the power supply device and the information display device according to the present invention has been described through the first to fourth embodiments. However, the present invention is not limited to this. The present invention can be applied to a device using at least two power supplies in the same manner as described above. For example, large C
RT and LED display devices perform various signal processing and drive control using a low voltage of about 5 V,
Display driving is performed using high voltages of about 1 k to 2 kV and about 10 to 100 V, respectively. Also, for example, in devices other than the information display device such as an electric cooker, about 5 V
The heating control is performed using the low voltage of
Heating is performed using a high voltage of 200 V, so that the present invention can be applied.

[0052]

Since the present invention is configured as described above, it has the following effects.

In the power supply device according to the present invention, a low-voltage power supply for generating a low voltage to be output to an external device, a magnetism generating element connected in series to the low-voltage power supply, A magnetic element such as a Hall element for electrically detecting a magnetic field generated by a current flowing to the external device, and a high-voltage power supply for generating a high voltage for output to the external device. After detecting by the magnetoelectric element that a predetermined low voltage has been output to the external device,
Since the high-voltage power supply unit outputs a high voltage to the external device, the power supply device and the external device are used to detect that the low-voltage power supply unit outputs a predetermined low voltage to the external device. Even if a dedicated line is not provided between the power supply device and the power supply device, it is possible to obtain a power supply device that can prevent inadvertent output of a high voltage to an external device.

Further, in the power supply device according to the present invention, after detecting that a predetermined low voltage is output from the low-voltage power supply unit to the external device, a certain time is passed from the high-voltage power supply unit to the external device. Since high voltage is output,
A high voltage can be prevented from being applied to the external device before predetermined initialization is performed in the external device, and a power supply device that can reduce the failure of the power supply device and the external device can be obtained. .

Further, in the power supply device according to the present invention, since the diode whose forward direction is from the external device toward the low-voltage power supply unit is connected in parallel to the magnetism generating element,
An abnormal voltage can be prevented from being generated in the power supply device when the output current changes sharply, and a power supply device with high reliability and few failures can be obtained.

Further, in the power supply device according to the present invention, a low-voltage power supply for generating a low voltage, a high-voltage power supply for generating a high voltage, and a high-voltage power supply connected between the high-voltage power supply and GND. An impedance element and a series connection circuit of a switching element, wherein the switching element is turned off with a predetermined correlation with the output of the low-voltage power supply, and turned on with a predetermined correlation with the output of the high-voltage power supply.
Therefore, the charge accumulated in the capacitor (or the parasitic capacitance) in the output section of the high-voltage power supply section can be appropriately charged and discharged, and a power supply device excellent in safety and output characteristics can be obtained. .

In the power supply according to the present invention, a low-voltage power supply for generating a low voltage for output to an external device and a medium-voltage power supply for generating a medium voltage for output to the external device are provided. A high-voltage power supply for generating a high voltage for output to the external device, wherein the low-voltage power supply and the medium-voltage power supply output a low voltage and a medium voltage to the external device. After receiving a signal indicating that the external device operates normally by the medium voltage, the high-voltage power supply unit outputs a high voltage to the external device. The failure of the high-voltage load unit can be detected before the voltage is output, and a power supply device that does not cause a further failure by applying a high voltage to the failed high-voltage load unit can be obtained.

Further, in the information display device according to the present invention, since the power supply device as described above and the display device driven by the power supply device are provided, more reliable and safe information display is achieved. A device can be obtained.

[Brief description of the drawings]

FIG. 1 is a schematic configuration diagram illustrating a plasma display as an example of an information display device according to a first embodiment of the present invention;

FIG. 2 is a diagram illustrating an example of a detection unit according to the first embodiment of the present invention.

FIG. 3 is a diagram illustrating a plasma display and a detection unit according to the first embodiment of the present invention.

FIG. 4 is a diagram illustrating another power supply unit according to a second embodiment of the present invention.

FIG. 5 is a diagram illustrating a plasma display as an example of an information display device according to a third embodiment of the present invention.

FIG. 6 is a diagram illustrating a plasma display as an example of an information display device according to a fourth embodiment of the present invention.

FIG. 7 is a diagram illustrating a conventional plasma display.

FIG. 8 is a diagram illustrating another conventional plasma display.

[Explanation of symbols]

1 detection unit, 2 power supply control circuit, 3 low voltage load unit, 4 high voltage load unit, 5 drive control unit, 6 high voltage control unit, 7 internal power supply, 8 X drive unit, 9 Y drive unit, 10 W drive unit, 15 coils, 16, 32
Diode, 17 Hall element, 18 amplifier, 1
9 reference voltage source, 20 comparator, 21, 25, 48
Transistor, 22, 50 collector, 23 resistance element, 24, 40 delay circuit, 26 load resistance, 2
7 High-voltage output section, 28 GND section, 29 capacitor, 30 operation confirmation power supply, 31 resistor, 33 detection circuit section, 34 confirmation cable, 35 detection signal, 36 display device section, 37 display panel, 38
Power supply unit, 39 Low voltage power unit, 41 High voltage power unit, 42 Low voltage cable, 43 Return cable,
44 High voltage cable, 45 GND cable, 46
Connection terminal, 47 detection circuit, 49 base, 51
Relay cable, 52 ground point.

──────────────────────────────────────────────────続 き Continued on the front page (51) Int.Cl. ⁷ Identification symbol FI Theme coat ゛ (Reference) H02H 11/00 H02H 11/00 B

Claims (6)

[Claims] 1. A low-voltage power supply for generating a low voltage for output to an external device, a magnetism generating element connected in series to the low-voltage power supply, and a magnetic field generated by a current flowing through the magnetism generation element And a high-voltage power supply for generating a high voltage for output to the external device, wherein the low-voltage power supply unit supplies the external device with a predetermined low voltage. A power supply device, wherein the high-voltage power supply unit outputs a high voltage to the external device after detecting that the voltage has been output by the magnetoelectric element. 2. A high voltage is output from the high voltage power supply to the external device after a certain time has been detected after detecting that a predetermined low voltage has been output from the low voltage power supply to the external device. The power supply device according to claim 1, wherein: 3. The power supply device according to claim 1, wherein a diode having a forward direction from the external device toward the low-voltage power supply unit is connected in parallel to the magnetism generating element. 4. A low-voltage power supply for generating a low voltage, a high-voltage power supply for generating a high voltage, and the high-voltage power supply and GND.
A series connection circuit of an impedance element and a switching element connected between the switching element and the switching element. The switching element is turned off with a predetermined correlation with the output of the low-voltage power supply, and the output of the high-voltage power supply is A power supply device which is turned on with a correlation of 5. A low-voltage power supply for generating a low voltage for output to an external device, a medium-voltage power supply for generating a medium voltage for output to the external device, and a power supply for outputting to the external device. A high-voltage power supply for generating a high voltage, wherein the low-voltage power supply and the medium-voltage power supply output a low voltage and a medium voltage to the external device, and the external device operates normally by the low voltage and the medium voltage. A high-voltage power supply unit that outputs a high voltage to the external device after receiving a signal indicating that the operation has been performed. 6. An information display device comprising: the power supply device according to claim 1; and a display device section driven by the power supply device.