JP2003098991A - Light emitting diode display device and control method therefor - Google Patents

Abstract

PROBLEM TO BE SOLVED: To make even many LEDs controllable, and to control a fluorescent display tube and the LEDs simultaneously. SOLUTION: A control signal from a timing control circuit 11 is supplied to a gate electrode of a high voltage FET 12. The drain electrode of the FET 12 is pulled up to +5 V, and the source electrode thereof is connected with a fluorescent display tube voltage circuit 16' via a pull-down resistor 13 and a terminal 15. The voltage circuit 16' is grounded. A grid driving signal/an anode driving signal is outputted from the source electrode of the FET 12 to the fluorescent display tube via an output terminal 14. When the FET 12 is OFF, the grid/anode electrode is pulled down to a negative voltage and thus electrons cannot get to the anode electrode, therefore, the fluorescent display tube is turned off. When the FET 12 is ON, the grid or anode electrode is pulled up to a positive voltage and thus the electrons are accelerated and get to the anode electrode, therefore, the fluorescent display tube is turned on.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a light emitting diode display device for controlling a fluorescent display tube or a light emitting diode used as a display device and a control method thereof.

[0002]

2. Description of the Related Art In many AV (Audio & Visual) devices such as VTRs (Video Tape Recorders), car audios and stereo components, fluorescent display tubes and light emitting diodes (LEDs) are used as display devices.
de) (hereinafter referred to as "LED"). In order to turn on a large number of LEDs, conventionally, a method of outputting a signal using a dynamic scan controller is generally used because of power consumption, wiring between components, and limitation of the number of ports for controlling LEDs. It was target. This is a so-called dynamic lighting system.

However, as LEDs have been replaced by other devices as display elements, LEDs have become more affordable.
Many of the dynamic scan controllers for PC have been discontinued, and most of them have disappeared at present.

On the other hand, LEDs have been developed to have ultra-high brightness and small size, which were not available in the past, and in terms of colors, blue and white, which were not available in the past, have been developed. Moreover, the demand for it has increased.

If a small amount of LEDs are used, it is possible to control them directly from the port of the microprocessor or use a data holding device, eg a latch, for static lighting. This is the so-called static lighting method.

[0006]

However, in order to control a large number of LEDs at the same time, the dynamic lighting method is more advantageous than the static lighting method in terms of power consumption and wiring between components, and sometimes the dynamic lighting method is used. A lighting method may be required.

However, as described above, most of the LED-dedicated controllers for operating the LEDs in the dynamic lighting system have disappeared from the market, so timer control can be performed by software using a vacant port of the microprocessor. There are more and more situations in which the method of generating timing by using is forced.

If the range (scale) in which the LED can be turned on by software is advantageous in terms of parts cost, once the number handled increases and exceeds the allowable amount, "LED lighting dedicated microcomputer (macro processor)""
The situation has also arisen.

Further, since one device, for example, a controller or a microprocessor does not have a function for controlling the fluorescent display tube and the LED at the same time,
Under the current circumstances, either one (in many cases, LED) control is redesigned according to the situation, or a control block is added as a separate circuit.

However, in many cases, the equipment uses a fluorescent display tube controller / driver (hereinafter referred to as “fluorescent display tube driver”) or a microprocessor equipped with a function (peripheral) for controlling the fluorescent display tube. Therefore, if the LED can be controlled in a unified manner by using this device or function, the load of software will be lightened and more flexible design will be possible.

Therefore, the object of the present invention is to provide a large number of LEs.
Even if it is D, it can be easily controlled, and the fluorescent display tube and LE
An object of the present invention is to provide a light emitting diode display device capable of controlling D and D at the same time, and a control method thereof.

[0012]

According to a first aspect of the present invention, in a light emitting diode display device for controlling lighting / extinguishing of a plurality of light emitting diodes, when a fluorescent display tube is connected, a plurality of grids are provided. And a second output terminal group for giving a drive signal selectively to a plurality of anodes when a fluorescent display tube is connected. Controller / driver, a plurality of switch elements having a plurality of control electrodes connected to at least one of the first and second output terminal groups, and a plurality of switch currents whose drive currents are turned on / off by the plurality of switch elements. A light emitting diode display device comprising a light emitting diode.

According to a third aspect of the present invention, in a light emitting diode display device for controlling lighting / extinguishing of a plurality of light emitting diodes, when a fluorescent display tube is connected, the phases are sequentially shifted with respect to a plurality of grids. A first signal generating means for generating a scan signal and a second signal generating means for selectively generating a drive signal for a plurality of anodes when the fluorescent display tube is connected; And a controller / driver having a plurality of switch elements having the plurality of control electrodes connected to the signal generating means, and a plurality of light emitting diodes whose driving currents are turned on / off by the plurality of switch elements. Is a light emitting diode display device.

According to a fourth aspect of the present invention, in a control method of a light emitting diode display device for controlling lighting / extinguishing of a plurality of light emitting diodes, when a fluorescent display tube is connected,
A controller / driver outputs a scan signal whose phase is sequentially shifted to a plurality of grids and a drive signal selectively to a plurality of anodes, and at least one of the scan signal and the drive signal controls a plurality of switch elements. A method of controlling a light emitting diode display device, characterized in that a driving current of the light emitting diode supplied to the electrodes is turned on / off by a plurality of switch elements.

According to a sixth aspect of the present invention, in a control method of a light emitting diode display device for controlling lighting / extinguishing of a plurality of light emitting diodes, when a fluorescent display tube is connected,
In the controller / driver, one of a scan signal that is sequentially generated with respect to a plurality of grids and a drive signal that is selectively generated with respect to a plurality of anodes is supplied to the control electrodes of the plurality of switch elements, A method of controlling a light emitting diode display device, comprising: a light emitting diode whose driving current is turned on / off by a plurality of switch elements.

In the inventions of claims 1 and 4, when the fluorescent display tube is connected, a scan signal whose phase is sequentially shifted from a controller / driver to a plurality of grids, and selective to a plurality of anodes. And the drive signal is output to the control electrodes of the plurality of switch elements, and the plurality of switch elements can turn on / off the drive currents of the plurality of light emitting diodes. That is, the controller / driver for the fluorescent display tube can control the turning on / off of the plurality of light emitting diodes.

In the inventions of claims 2 and 5, first output means for outputting the voltage and / or current for the fluorescent display tube, which are provided in the first and second output terminal groups of the controller / driver, and light emission The second output means for outputting the voltage and / or current for the diode can be appropriately switched according to the fluorescent display tube or the light emitting diode connected to the output section of the controller / driver. That is, lighting / extinction of the fluorescent display tube and lighting / extinction of the light emitting diode can be controlled by the same controller / driver for the fluorescent display tube.

In the inventions of claims 3 and 6, when the fluorescent display tube is connected, a scan signal whose phase is sequentially shifted with respect to a plurality of grids and a drive signal selectively with respect to a plurality of anodes. It is possible to directly control the turning on / off of the light emitting diode by a controller / driver having a switch element that turns on / off according to the scan signal or the driving signal.

[0019]

BEST MODE FOR CARRYING OUT THE INVENTION An embodiment of the present invention will be described below with reference to the drawings. It should be noted that components having the same function throughout the drawings are designated by the same reference numerals to avoid duplication of description. FIG. 1 shows a schematic configuration of a display control device of a first embodiment to which the present invention is applied. The interface 1 outputs the data signal input from the system bus to the local bus 3. The controller 2 generates and outputs a display signal according to the input of the data signal. The fluorescent display tube driver 4 is a driver for driving the fluorescent display tube, and outputs a predetermined drive signal, for example, a grid drive signal and an anode drive signal according to the display signal from the controller 2. The display panel 5 is composed of, for example, a fluorescent display tube and / or an LED, and displays according to a grid drive signal and an anode drive signal from the fluorescent display tube driver 4.

A control method for displaying on the display panel 5 will be described with reference to the flow chart shown in FIG. In step S11, the power of the apparatus main body is applied and control is started. In step S12, a so-called initialization operation of initializing the memory variable is executed.

In step S13, the controller transmits a control signal for reading a predetermined data signal from the system bus to the interface 1. The interface 1 receiving this control signal reads the data signal from the system bus, temporarily stores the data signal, and then transmits the data signal to the controller 2 via the local bus 3. That is, in this step, the data signal is fetched from the main board of the device.

In step S14, the controller 2 analyzes the data signal supplied from the interface 1, generates a display signal related to the operation state according to the analysis result, and outputs the display signal to the fluorescent display tube driver 4. .

In step S15, the current analysis result and the previous analysis result are compared to detect the presence or absence of change. When it is determined that the current analysis result and the previous analysis result are the same, control is returned to step S13, and when it is determined that the current analysis result and the previous analysis result are different, step S1
Control is transferred to 6.

In step S16, the fluorescent display tube driver 4 outputs a grid drive signal and an anode drive signal to the display panel 5 according to the input display signal. Then, the display panel 5 drives and displays the fluorescent display tube and / or the LED indicating the operating state in accordance with the input grid drive signal and anode drive signal.

In step S17, it is determined whether or not the display of all the fluorescent display tubes and / or LEDs to be displayed is completed. If it is determined that the entire display is completed, the control returns to step S13, and if it is determined that the entire display is not completed yet, the control returns to step S16.

In the control method of FIG. 2, the current analysis result and 1
The presence / absence of a change is detected by comparing with the immediately preceding analysis result, and when it is determined that there is a change, the grid drive signal and the anode drive signal are displayed on the display panel 5 only when there is the change.
However, the grid drive signal and the anode drive signal may be supplied to the display panel 5 according to the analysis result regardless of the previous analysis result.

Here, the principle of the dynamic scan type fluorescent display tube scanning will be described with reference to FIGS. The fluorescent display tube shown in FIG. 3 is a direct-heat type triode. Electrons emitted by passing a current through the filament are accelerated by the potential (plus potential) of the grid electrode, and the fluorescent substance When it collides with the applied anode electrode, it emits light (lights up). Further, when the voltage of the anode electrode or the grid electrode is set to a certain value or less, electrons cannot reach the anode electrode. In this case, the fluorescent display tube is turned off. In FIG. 3, the description is given by the “negative power supply method” in which the filament side is set to a negative potential and the grid electrode is set to a positive potential.

FIG. 4 shows the potential states of the grid drive signal and the anode drive signal during the dynamic scan of the grid electrode and the anode electrode. 4A, 4B, and 4C are examples of grid drive signals, and FIG.
4E and 4F are examples of the anode drive signal. In this example, 3 × 3 = 9 segments are controlled. The grid drive signal performs grid scanning in which the grid drive signals A, B, and C are sequentially set to a high level (hereinafter referred to as "H level") as shown in FIGS. 4A, 4B, and 4C.

During the grid scan, the anode drive signal selects which of the anode drive signals A, B, and C is set to the H level as shown in FIGS. 4D, 4E, and 4F. As shown in FIG. 4G, when both the grid drive signal and the anode drive signal become H level, the fluorescent display tube lights up.

In FIG. 4G, as an example, the thick lines indicate that the segments are on, and the thin lines indicate that the segments are off. In FIG. 4, since both drive signals are at the H level only when the combination of the grid drive signal A and the anode drive signal A and the combination of the grid drive signal C and the anode drive signal C are selected, among the nine segments This means that two lights and seven lights go out. Since the frequency of this grid scan is required to be fast enough for humans not to perceive flicker, it is often a cycle of 60 Hz to 400 Hz.

An example of the p-channel output type fluorescent display tube driver 4 is shown in FIG. The control signal output from the timing control circuit 11 has a high breakdown voltage F.
It is supplied to the gate electrode of the ET (Field Effect Transistor) 12. ON / OFF of the high breakdown voltage FET 12 is controlled by this control signal. The drain electrode of the high breakdown voltage FET 12 is pulled up to + 5V, and its source electrode is
It is connected to the terminal 15 via the pull-down resistor 13. A voltage circuit 16 for a fluorescent display tube is connected to the terminal 15. A negative voltage (pull-down voltage), generally a voltage of about several tens of volts is applied to the voltage circuit 16 for the fluorescent display tube. Further, a grid drive signal or an anode drive signal is output from the output terminal 14 derived from the source electrode of the high breakdown voltage FET 12 to the fluorescent display tube.

When the high breakdown voltage FET 12 is off, the grid or the anode electrode is pulled down (driven) to a negative voltage, and electrons cannot reach the anode electrode, so the fluorescent display tube is turned off. When the high breakdown voltage FET 12 is on, the grid or the anode electrode is pulled up to a positive voltage, so that electrons are accelerated and reach the anode electrode, so that the fluorescent display tube is turned on. As described above, many fluorescent display tube drivers or microcomputers incorporating the drivers incorporate the high breakdown voltage FET 12 and the pull-down resistor 13.

This fluorescent display tube is currently used in many electronic devices such as VTRs and car audio devices. Therefore, many types of controller / driver ICs (Integrated Circuits) for controlling the fluorescent display tube are provided by various companies. Moreover, even in built-in microcomputers, some of them have high withstand voltage specifications and are equipped with peripherals (peripheral devices) that directly control the fluorescent display tube. , Is a general display element. Therefore, if the control system of these devices can be applied to the LED, both elements can be treated in the same way, and improvement in product design efficiency can be expected.

Therefore, FIG. 6 shows a second embodiment in which the p-channel output type fluorescent display driver 4 shown in FIG. 5 is applied to an LED. Since there is often no negative voltage power supply in the circuit that lights only the LED, the circuit shown in FIG.
As shown in, the fluorescent display tube voltage circuit 16 'is grounded. That is, in this example, the pull-down voltage becomes the ground.

Then, referring to the timing chart of FIG. 4 described above, when the anode driving signal and the grid driving signal are at the H level at the same time during the grid scanning, the fluorescent display is lit up and the grid scanning is in progress. When the anode drive signal is at a low level (hereinafter, referred to as "L level"), the fluorescent display tube is turned off. Consider the lighting of the LED by utilizing this timing.

FIG. 7 shows a third embodiment in which an LED is driven by using the fluorescent display tube driver 4. The anode drive signal A from the fluorescent display tube driver 4 is an n-channel type F
It is supplied to the gate electrode of ET21 _A. The anode drive signal B from the fluorescent display tube driver 4 is an n-channel FE
It is supplied to the gate electrode of T21 _B. The anode drive signal C from the fluorescent display tube driver 4 is an n-channel type FET
It is supplied to the gate electrode of 21 _C. FET21 _A , 2
The drain electrodes of 1 _B and 21 _C are pulled up to the LED lighting power supply V _LED .

The anode electrodes of the LEDs 23 _A1 , 23 _A2 , and 23 _A3 are connected to the source electrode of the FET 21 _A via the resistor 22 _A. LEDs 23 _B1 , 23 _B2 , and 23
The anode electrode of _B3 is connected to the source electrode of the FET 21 _B via the resistor 22 _B. The anode electrodes of the LEDs 23 _C1 , 23 _C2 , and 23 _C3 are FETs via a resistor 22 _C.
It is connected to the source electrode of 21 _C.

The drain electrodes of the n-channel type FET 24 _A are connected to the cathode electrodes of the LEDs 23 _A1 , 23 _B1 , and 23 _C1 . The grid drive signal A is supplied from the fluorescent display tube driver 4 to the gate electrode of the FET 24 _A. The source electrode of the FET 24 _A is grounded.

The drain electrodes of the n-channel FET 24 _B are connected to the cathode electrodes of the LEDs 23 _A2 , 23 _B2 , and 23 _C2 . The grid drive signal B is supplied from the fluorescent display tube driver 4 to the gate electrode of the FET 24 _B. The source electrode of the FET 24 _B is grounded.

The cathode electrodes of the LEDs 23 _A3 , 23 _B3 , and 23 _C3 are connected to the drain electrodes of the n-channel FET 24 _C. The grid drive signal C is supplied from the fluorescent display tube driver 4 to the gate electrode of the FET 24 _C. The source electrode of the FET 24 _C is grounded.

Although the FET is used in FIG. 7,
A transistor may be used. However, when the transistor is used instead of the FET, a bias resistor is required depending on the circuit type.

As described above, FIG. 7 shows an example of a circuit which fully utilizes the dynamic scan function. This is a circuit in which an external FET and an LED are connected instead of the fluorescent display tube, and the fluorescent display driver 4 performs dynamic scan lighting of the LED.

Although FIG. 7 shows a form in which the LED is connected to the cathode electrode side to the common (common), the circuit can be configured in the same way even with the anode common type connection. A circuit that is turned on at the scan timing of the grid drive signal is connected to the common cathode electrode side of the LED. Similarly, a circuit that is turned on at the scan timing of the anode drive signal is also connected to the anode electrode side. Therefore, the LED can be controlled by the external circuit as it is without modifying the timing of the fluorescent display tube driver 4. In case of dynamic scanning, the LED also has 60Hz to prevent flickering.
Turn on at a cycle of 400 Hz. Therefore, the timing circuit can use exactly the same circuit. In addition, LED
In the circuit for lighting, the pull-down voltage is set to the ground similarly to the above.

The FET shown in FIG. 7 is of a type that turns on when the gate electrode becomes H level. According to the timing chart shown in FIG. 4, the LEDs are turned on during the time period when the anode drive signal and the cathode drive signal simultaneously become H level. Since this timing is the same as the timing of turning on the fluorescent display tube, the control of the controller is the same, and therefore the turning on / off can be performed by the same algorithm without considering the difference between the two.

Next, the fourth practical example when the number of LEDs is small.
FIG. 8 shows a connection example of the embodiment. This FIG. 8 shows three LEs.
D23_A, 23_B, And 23_CIs an example of driving
It These LEDs 23_A, 23_B, And 23_CThe Cassaw
The LED is grounded and these LEDs are only on the anode side.
ON / OFF is controlled. To apply this format
Therefore, the fluorescent display tube controller is as shown in FIG.
Even with dynamic scan type, static
It can also be used with the scan type. At this time, Dyna
Mick scan and static scan
In the case of lighting, there is a difference in lighting time.
Resistance 22 that determines the flow_A, 22_B, And 22 _CThe value of is different
Become. For example, in the case of dynamic scan, when it is lit
Since the time is short, in order to turn on the LED with the predetermined brightness
Is a resistor 22 for current limiting_A, 22_B, And 22_Cof
It is necessary to reduce the value.

FIG. 9 shows a fifth embodiment in which the LED is controlled by using the FET incorporated in the fluorescent display tube driver 4. The drain electrode of the FET 12 is LE
It is pulled up to the power supply V _LED for D lighting. One of the pull-down resistors 13 may be unconnected. The resistor 22 is inserted between the output terminal 14 and the anode electrode of the LED 23. The cathode electrode of the LED 23 is the driver circuit 31.
Connected with. The driver circuit 31 may be composed of the FETs 24 _A , 24 _B , and 24 _C as shown in FIG. 7 described above, or may be simply grounded as shown in FIG.

In this way, the fluorescent display tube driver 4 to L
The conditions for directly turning on / off the ED are as follows: the current flowing in the LED is covered by the FET incorporated in the fluorescent display tube driver 4, for example, the maximum rating of the current flowing in the LED is allowable by the fluorescent display tube driver 4. It can be used within the electric power, and the LED is turned on / off (lit / lit)
It is necessary to satisfy that the generated current can be used by the FET in the fluorescent display tube driver 4. -The power supply for the fluorescent display tube and the power supply for lighting the LED can be covered by the same power supply.-In many cases, the power supply described as "for LED lighting" is I
Since it is common with the power source of C itself, its voltage can also be used for LED lighting.

When such conditions are satisfied, the LED can be directly controlled by the fluorescent display tube driver 4, so that an external FET is not required, which is advantageous in terms of the number of parts and cost. In particular, since many types of LEDs that have achieved high brightness with a small current have been developed in recent years, it is possible to satisfy the usage environment within the maximum absolute rating even if the transistors in the fluorescent display tube are directly used. it can.

Further, in the example shown in FIG. 9, only one system is described, but it is the same as in FIG. 7 described above, and the FET built in the fluorescent display tube driver 4 directly turns on / off the current. Only the part that is performed is different from FIG. 7.

The fluorescent display tube driver 4 is used for the LE and the fluorescent display tube.
A sixth embodiment in which D and D are mixed and driven will be described with reference to FIG. The anode electrode of the diode 42 is connected to the input terminal 41, and the cathode electrode thereof is the FET 44.
Connected to the gate electrode of. A resistor 43 is provided between the cathode electrode of the diode 42 and the ground. The diode 42 is provided so that a negative voltage when driving the fluorescent display tube is not applied to the FET 44, and a high breakdown voltage diode is used. The resistor 43 is a pull-down resistor, and is used for pulling down to the L level to determine the potential when the FET 44 is off.

The drain electrode of the FET 44 is pulled up to the LED lighting power source V _LED . A resistor 4 is provided between the source electrode of the FET 44 and the anode electrode of the LED 46.
5 is inserted. The drain electrode / source electrode of the FET 54 is provided between the cathode electrode of the LED 46 and the ground.

The anode electrode of the diode 52 is connected to the input terminal 51, and the cathode electrode thereof is connected to the gate electrode of the FET 54. A resistor 53 is provided between the cathode electrode of the diode 52 and the ground. The diode 52 has a negative voltage of FE when driving the fluorescent display tube.
A high breakdown voltage diode is used so as not to cover T54. The resistor 53 is a pull-down resistor, and is used for pulling down to the L level for determining the potential when the FET 54 is off.

A seventh embodiment of the fluorescent display tube driver 4 which can be used as both a fluorescent display tube and an LED will be described with reference to FIG. The block diagram shown in FIG. 11 is an embodiment in which a circuit for selecting which of the fluorescent display tube and the LED is connected is mounted inside the IC of the fluorescent display tube driver 4. In this embodiment, the LED dynamic scan will be described as an example in which the cathode electrode is shared.

The timing generating block 61 is provided with a cathode control circuit 62 and a grid / anode control circuit 63. A pulse signal is supplied from the cathode control circuit 62 to the gate electrode of the FET 44. The drain electrode of the FET 44 is pulled up to the reference power supply V of the fluorescent display tube driver 4. The source electrode of the FET 44 has a voltage circuit 6 for a fluorescent display tube via a switch circuit 61 and a pull-down resistor 62.
Connected with 3. The source electrode of the FET 44 is connected to the anode electrode of the LED 46 via the resistor 45.

Grid / anode control circuit 63
From the pulse signal is supplied to the gate electrode of the FET 54. The drain electrode of the FET 54 is a switch circuit 64.
Is pulled up to the reference power source V of the fluorescent display tube driver 4 via. The source electrode of the FET 54 is connected to the switch circuit 66. Terminal 6 of switch circuit 66
6L is grounded, and the terminal 66F is connected to a fluorescent display tube voltage circuit 68 via a pull-down resistor 67. FET5
The drain electrode and the source electrode of 4 are the switch circuit 6
5 and is connected to the cathode electrode of the LED 46.

In the example of FIG. 11, an example in which the cathode electrode is used as a common is explained, but it is also possible to develop it into a form in which the anode electrode is used in common.

When the LED 46 is connected, the LED 46
Connect the FET44 that supplies power to the anode electrode of
The switch circuit 61 is turned off in order to stop the power supply from the fluorescent display tube power supply circuit 63. Further, the switch circuit 64 is turned off so that the reference voltage is not applied to the cathode electrode of the LED 46, and in order to connect the cathode electrode of the LED 46 and the drain electrode of the FET 54,
In the switch circuit 65, the terminal 65L is selected and the LED4
In order to ground the cathode electrode of 6, the switch circuit 66
Then, the terminal 66L is selected.

When a fluorescent display tube is connected, FET44
The switch circuit 61 is turned on in order to switch and output one of the positive power supply and the negative pull-down power supply for turning on / off the fluorescent display tube. F
In order to supply an H level signal to the grid electrode of the fluorescent display tube when the ET 54 is turned on, the switch circuit 6
4 is turned on, and in order to control the grid electrode of the fluorescent display tube, the terminal 65F is selected in the switch circuit 65 and connected to the source electrode of the FET 54. Then, in order to output the negative pull-down power supply for turning off the fluorescent display tube from the FET 54, the terminal 66F is selected in the switch circuit 66.

In FIG. 11, in the form of a switching circuit,
Although the functions are distinguished, it is not necessary to form the switch inside the IC, and another form may be used as long as the same operation is satisfied.

Further, the switching circuit shown in FIG.
Depending on the device connected to the IC port, it can be freely set from the outside. Therefore, the timing generation block 61 for generating the scan timing may be the same regardless of whether the fluorescent display tube or the LED is connected. On the other hand, it is only the voltage / current driver type that becomes the final output stage that distinguishes the two, and it is possible to support either component by only switching this part. .

For example, when the LED 46 is connected, the fluorescent display tube voltage circuit 68 may be grounded outside the fluorescent display tube driver 4 as shown in FIG.
In this case, the switch circuit 66 becomes unnecessary. Therefore, when the fluorescent display tube is connected, as shown in FIG. 5, the fluorescent display tube voltage circuit 6 is provided outside the fluorescent display tube driver 4.
8 is not grounded.

When the circuit of FIG. 11 is built in the microprocessor, the mask option setting function is used to
It is also possible to predetermine the method before or during the chip manufacturing process.

As described above, since the IC has a plurality of ports, it is possible to arbitrarily select how many of the plurality of ports are set to the fluorescent display tube specification and how many ports are set to the LED specification. By making it possible, one controller / driver IC can scan the fluorescent display tube and the LED in a mixed manner.

In this embodiment, the "negative power supply system" is described in which the filament side is set to a negative potential and the grid electrode is set to a positive potential. However, the grid electrode and the anode electrode are biased to a higher voltage. There is also a positive power supply system.
Even with the "positive power supply system", similar effects can be obtained with similar circuits.

Although a high breakdown voltage FET is used in this embodiment, a high breakdown voltage transistor may be used,
Bipolar transistors may be used.

In this embodiment, the LED is turned on when the FET provided on the anode electrode side and / or the cathode electrode side of the LED is turned on, and is turned off when the FET is turned off.
Is turned off, the LED may be turned on when the FET is turned off, and the LED may be turned off when the FET is turned on.

[0067]

According to the present invention, since the fluorescent display tube driver is used for lighting the LED, the function of the fluorescent display tube driver can be directly applied to the LED. For example, a fluorescent display tube has a dimmer function that changes the brightness of a display segment. This is a function of shortening the time for which the grid drive signal and the anode drive signal are at the H level at the grid scan timing to darken them. Similarly, in the LED, when the H level time is shortened, the FET ON time is also shortened, so that the apparent light emission intensity is lowered and the LED becomes dark. Therefore, if you use this function, you have not seen much before,
The brightness of the LED can be easily adjusted.

According to the present invention, by selecting the type of external FET / transistor, the fluorescent display tube and L
It is also possible to combine the EDs and control them with a single controller / driver. In this case, the external FET / transistor for controlling the LED may have a withstand voltage at a negative voltage (minus several tens of volts) and may be selected to have a characteristic of turning off at that voltage. Alternatively, by inserting a high breakdown voltage diode and a pull-down resistor in the gate electrode / base electrode, it is possible to easily realize a circuit in which the fluorescent display tube and the LED are mixed.

According to the present invention, it has been found that the fluorescent display tube driver can be applied to LED lighting with a simple device. Therefore, the LED dedicated driver will be abolished in the future, and the control will be concentrated only on the fluorescent display tube dedicated driver. It is possible.

According to the present invention, since the LED can be controlled even in the case of a static drive, even when the number of ports is limited, such as a built-in microcomputer, if there are extra ports for the fluorescent display tube, Since it is not necessary to prepare a dedicated port for the LED, it is possible to realize a circuit with more reduced parts and cost.

According to the present invention, by incorporating the circuit of the present invention and the circuit originally included in the fluorescent display tube driver into the same IC, an LSI capable of using both the fluorescent display tube and the LED can be obtained. Can be made. As described above, since the LEDs of recent years have been developed to have a small amount of current and high brightness, an IC of a type incorporating a drive element.
It makes sense to realize.

[Brief description of drawings]

FIG. 1 is a block diagram of a first embodiment of a display control device to which the present invention can be applied.

FIG. 2 is a flowchart for explaining control of the first embodiment of the display control device to which the present invention can be applied.

FIG. 3 is a schematic view of an example of a fluorescent display tube that can be applied to the present invention.

FIG. 4 is a timing chart of an example applicable to the present invention.

FIG. 5 is a block diagram of an example of controlling a fluorescent display tube by applying the present invention.

FIG. 6 is a block diagram of a second embodiment for controlling an LED to which the present invention has been applied.

FIG. 7 is a block diagram of a third embodiment for controlling an LED to which the present invention has been applied.

FIG. 8 is a block diagram of a fourth embodiment for controlling an LED to which the present invention has been applied.

FIG. 9 is a block diagram of a fifth embodiment for controlling an LED to which the present invention has been applied.

FIG. 10 is a block diagram of a sixth embodiment for controlling an LED to which the invention is applied.

FIG. 11 is a block diagram of a seventh embodiment for controlling an LED to which the invention is applied.

[Explanation of symbols]

11 ... Timing control circuit, 12 ... F
ET, 13 ... Pull-down resistance, 16, 16 '...
Voltage circuit for fluorescent display tube

   ─────────────────────────────────────────────────── ─── Continued front page    (72) Inventor Yutaka Sudo             6-735 Kita-Shinagawa, Shinagawa-ku, Tokyo Soni             -Inside the corporation F term (reference) 5C080 AA07 AA08 BB01 DD22 DD26                       FF10 HH14 JJ02 JJ03 JJ04                       KK42

Claims (6)

[Claims] 1. A light emitting diode display device for controlling lighting / extinguishing of a plurality of light emitting diodes, wherein when a fluorescent display tube is connected, a scan signal whose phase is sequentially shifted is given to a plurality of grids. A controller / driver including an output terminal group and a second output terminal group that selectively supplies a drive signal to a plurality of anodes when the fluorescent display tube is connected, and the first and second To at least one of the output terminal groups of
A light emitting diode display device comprising: a plurality of switch elements to which the plurality of control electrodes are connected; and a plurality of light emitting diodes whose driving current is turned on / off by the plurality of switch elements. 2. The first and second output terminal groups output a voltage and / or current for the fluorescent display tube and a voltage and / or current for the light emitting diode. And a second output means for switching the first and second output means appropriately according to the fluorescent display tube or the light emitting diode connected to the first and second output terminal groups. The light emitting diode display device according to claim 1, wherein 3. A light emitting diode display device for controlling lighting / extinction of a plurality of light emitting diodes, wherein when a fluorescent display tube is connected, a scan signal whose phase is sequentially shifted with respect to a plurality of grids is generated. And a second signal generating means for selectively generating drive signals for a plurality of anodes when the fluorescent display tube is connected to the signal generating means, and the first or second signal generating means. A light emitting diode comprising a controller / driver including a plurality of switch elements to which the plurality of control electrodes are connected, and a plurality of light emitting diodes whose driving current is turned on / off by the plurality of switch elements. Display device. 4. A method for controlling a light emitting diode display device for controlling lighting / extinguishing of a plurality of light emitting diodes, wherein phases are sequentially shifted from a controller / driver to a plurality of grids when a fluorescent display tube is connected. The scan signal and the drive signal are selectively output to the plurality of anodes, and at least one of the scan signal and the drive signal is supplied to the control electrodes of the plurality of switch elements. A method for controlling a light emitting diode display device, characterized in that a driving current is turned on / off. 5. The controller / driver has first output means for outputting voltage and / or current for the fluorescent display tube and second output means for outputting voltage and / or current for the light emitting diode. 5. The control of the light emitting diode display device according to claim 4, wherein the first and second output means are appropriately switched according to the connected fluorescent display tube or light emitting diode. Method. 6. A control method of a light emitting diode display device for controlling lighting / extinguishing of a plurality of light emitting diodes, wherein when a fluorescent display tube is connected, a phase generated with respect to a plurality of grids is generated in a controller / driver. One of the sequentially shifted scan signal and the drive signal selectively generated for the plurality of anodes is supplied to the control electrodes of the plurality of switch elements, and the drive current is turned on / off by the plurality of switch elements. A method of controlling a light emitting diode display device, comprising: a diode.