JPH0447698A - Driving device for el lamp - Google Patents

Abstract

PURPOSE:To deal with driving plural kinds of EL lamps by means of a single driving device for EL lamp by selecting a drive frequency out of a storing device according to the kind of an EL lamp. CONSTITUTION:A CPU 1 reads data out of ports 1 to 3 of a built-in I/O port 1a, and reads the drive frequency of an EL lamp 15, which complies with the data read out of the ports 1 to 3, out of a ROM 12. The drive frequency read out of the ROM 12 is set in a frequency setting circuit 13, then a driving device for EL lamp is started in its operation to light the EL lamp 15. Then, after the decision on whether a request for resetting the drive frequency of the EL lamp exists or not is performed, if the result of the decision is YES, the data are read again out of the I/O port 1a. However, if the result is NO, the lighting operation of the EL lamp 15 continues at the present drive frequency. For example, if the I/O port 1a is based on a three-bit pattern, eight kinds of EL lamps at maximum are distinguished.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to an EL clamp driving device for driving an EL clamp used as a backlight for a liquid crystal display (hereinafter referred to as LCD).

[Prior Art] Conventionally, EL clamps have been widely used as backlights for LCDs, and EL clamp driving conditions vary depending on, for example, the EL clamp manufacturer and the EL clamp material.

Each EL clamp drive circuit is made to correspond to one specific type of EL clamp.

[Problems to be Solved by the Invention] However, in the above conventional example, as the number of EL clamp manufacturers increases, various types of EL clamps with different luminous colors and brightness have appeared on the market, and it is difficult to change the EL clamps.
A disadvantage is that the L-clamp drive circuit must be changed to adjust the drive frequency to an appropriate value.

[Means for Solving the Problems] The present invention has been made for the purpose of solving the above-mentioned problems, and includes the following configuration as one means for solving the above-mentioned problems.

That is, a storage means for storing a plurality of EL clamp drive frequencies, a discrimination means for discriminating the EL clamp type, and a means for selecting a drive frequency from the storage means based on the EL clamp type discriminated by the discrimination means. Equipped with

[Function] In the above configuration, the EL clamp can be lit at a drive frequency suitable for the EL clamp used.

[Embodiments] Hereinafter, preferred embodiments of the present invention will be described in detail with reference to the accompanying drawings.

FIG. 1 is a block diagram showing the configuration of an EL clamp motion device which is an embodiment of the present invention.

In FIG. 1, the CPUI controls the entire EL lamp driving device according to a program stored in the ROM 12. Further, a built-in I10 boat 1a is used as an input port, and switches 5 to 7 are connected to each port (ports 1 to 3). One side of each switch is connected to the power source (■) by resistors 8 to 10, respectively. It is pulled up to 0. Therefore, when switch 5 is ON, port
l becomes a ground potential (corresponding to logic 0), and becomes a power supply potential (corresponding to logic 1) when it is OFF. Other switches operate similarly.

The CPU reads the EL clamp drive frequency stored in the ROM 12 via a bus 11 consisting of an address bus, a data bus, and a control bus, and writes it to the frequency setting circuit 13. The frequency setting circuit 13 is
Inverter power supply 1 according to the frequency set by CPU1
The output signal fo is sent to 4. As a result, the inverter power supply 14 receives the signal f. The EL clamp 5 is excited and oscillates, driving the EL clamp 5 and lighting it up.

Next, the control procedure in the EL clamp motion device according to this embodiment will be explained according to the flowchart shown in FIG.

At step S1 in FIG.
The CPU reads data from ports 1 to 3 of the built-in I10 boat la. Then, in step S3, por
The driving frequency of the EL clamp 5 corresponding to the data read from t1 to t3 is read from the ROM 12. Continuation (In step S4, the drive frequency read from the ROM 12 is set in the frequency setting circuit 13, and then in step S5, the operation of the present EL lamp driving device is started, so that the EL clamp 5 is turned on.

In step S6, it is determined whether or not there is a request to reset the EL clamp drive frequency. If the result of the determination here is YES, the process returns to step S2 and data is read from the I10 boat 1a again. However, if the determination is NO, the EL clamp lighting operation continues at the current drive frequency.

In the EL clamp motion device of this embodiment, since the I10 port 1a has a 3-bit configuration, a maximum of eight types of EL clamps can be discriminated.

As explained above, according to this embodiment, the EL
The drive frequency suitable for the clamp can be set externally.
There is no need to prepare a drive circuit for the EL lamp, and the advantage is that it can always be driven at the optimum frequency.

Other examples Other embodiments according to the present invention will be described below.

FIG. 3 is a block diagram showing the configuration of an EL clamp motion device according to another embodiment. In this figure, the same components as those of the EL clamp motion device shown in FIG. 1 are given the same numbers, and detailed explanations will be omitted.

In FIG. 3, the EL unit 16 has an EL clamp 5 therein, and is connected to the EL clamp operating device main body 20 via a connector 17. The EL unit 16 has three power supply lines in addition to the two power supply lines, the GND line (corresponding to the 1st terminal of the connector) and the AC input power line (corresponding to the 2nd terminal of the connector), via the connector 17. The signal line (corresponding to terminals 3 to 5 of the connector) is immediately applied to determine the type of EL clamp.

When the EL unit 16 is connected to terminals 3 to 5 of the connector 17, the port of the I10 boat 1a built in the CPU
The potentials of rt1 to rt3 are determined, and from that potential pattern EL
The type of unit 16 can be determined. That is, the No. 5 terminal of the connector 17 is connected to portl of the I10 boat 1a.
, and its potential is at the GND level, so it is logically interpreted as 0. Similarly, terminals 3 and 4 of connector 17
The number terminals are connected to port 3.2 of I10 boat 1a, and at the same time, the power supply Vcc is connected to port 3.2 of I10 boat 1a.
Since it is pulled up to 1, its logic level is 1.

Needless to say, since the I10 boat 1a has a 3-bit configuration, a maximum of eight types of EL clamps can be discriminated.

As explained above, according to this embodiment, the type of EL clamp can be determined by connecting the unit housing the EL clamp to the EL clamp driving device, so there is no need to externally set the drive frequency according to the EL clamp. This has the advantage that driving can always be performed at the optimum frequency.

[Effects of the Invention] As explained above, according to the present invention, it is possible to set the optimum driving frequency for the EL clamp depending on the type of EL clamp, and the same EL lamp driving device can support multiple types of EL clamp driving. There is an effect that it can be done.

[Brief explanation of the drawing]

FIG. 1 is a block diagram showing the configuration of an EL clamp drive device according to an embodiment of the present invention, FIG. 2 is a flowchart showing a control procedure in the EL drive device according to the embodiment, and FIG. 3 is another embodiment. FIG. 2 is a block diagram showing the configuration of an EL clamp motion device according to the present invention. In the figure, 1-CPU, l a-・I10 port, 5-7・
...Switch, 8-10...Pull-up resistor, 11.
... bus, 12 ... ROM, 13 ... frequency setting circuit, 14 ... inverter power supply, 15 ... EL clamp 6 ... EL unit, 17 ... connector.

Claims (1)

[Scope of Claims] An EL lamp driving device that excites an EL lamp from the outside, comprising: storage means for storing drive frequencies of a plurality of EL lamps; discriminating means for discriminating the type of the EL lamp; and the discriminating means An EL lamp driving device comprising means for selecting a driving frequency from the storage means based on the determined type of EL lamp.