JPH10301523A - El driver circuit with composite function - Google Patents

Abstract

PROBLEM TO BE SOLVED: To drive an electromagnetic sounding body in addition to EL driving and to make the circuit small-sized and thin enough for surface mounting by providing a driving element with a switching terminal for an EL illumination command and a sounding body sounding command and effectively excluding the sound pressure band of the sounding body from the frequency band of a voltage boosting driving circuit for an EL light emission substrate. SOLUTION: The circuit block of an EL driver is constituted by short- circuiting electronic components such as the driving coil 132, chip capacitor 117, etc., of the electromagnetic sounding body 111 to a driving element 115 including an active element having terminals determined according to specifications instead of an inductance element on a circuit board. Thus, the driving coil 132 of the electromagnetic sounding body 111 is used instead of the inductance element of an EL driver circuit, so the arrangement of the inductance element from the EL driver can be eliminated. Consequently, the circuit board on which the EL driver circuit is mounted is more small-size and thinner and the entirety is regarded as one electronic component, which is effective in surface mounting.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an EL used for a backlight of a liquid crystal display device such as a cellular phone or a clock.
(Electroluminescence) The present invention relates to the configuration of an EL driver circuit for emitting light from a substrate. In particular, one of the electronic components of the EL driver circuit is configured by a driving coil of an electromagnetic sounding body, and the EL driver circuit has an EL lighting function. It has a composite function of the sounding body sound function.

[0002]

2. Description of the Related Art Conventionally, EL driver modules have been widely used to emit light from EL (Electroluminescence) elements used in backlights of liquid crystal display devices such as cellular phones and watches. As one of the conventional examples,
Japanese Patent Laying-Open No. 59-47853 (hereinafter referred to as Document A) discloses a configuration of an EL lighting circuit and a piezoelectric buzzer driving circuit.
The outline shown in FIG. 2 of Document A relates to (1) the configuration of the display unit and the driving circuit of the ringing unit of the individually selected calling receiver by ringing, and (2) the configuration of the display unit and the ringing unit. A feature of the configuration of the drive circuit is that a common step-up coil is provided for EL lighting and a piezoelectric buzzer drive, and this is switched by a switching transistor for operation.

FIG. 6 shows a configuration of a typical circuit block of a conventional EL driver, which has a function of converting a DC voltage to a required frequency, boosting the voltage, and driving an EL light emitting substrate. In the circuit block 200 of the EL driver, electronic components such as an inductance element 211 and a chip capacitor 212 are connected on a circuit board to a drive element 213 including an active element having a terminal determined in advance as described below. Be composed. Input power connection terminal 21
7 is a terminal 221 of the driving element 213, a terminal 215 of the drain-source voltage VDS is a terminal 222 of the driving element 213 via an inductance element 211, an EL lighting command terminal 216 is a terminal 220 of the driving element 213, and a chip capacitor. Reference numeral 212 denotes terminals 218 and 219 of the driving element 213.
The output terminals 223 and 224 of the drive element 213 are connected to the input terminals 226 and 227 of the EL substrate 214, respectively. There has been a strong demand for the EL driver circuit to be small and thin.

[0004]

However, document A
In (1) there is no mention that the drive circuit is configured to be surface mountable, (2) a common booster coil must be provided for EL lighting and piezoelectric buzzer drive, and a display unit and a sound generator are provided. However, there is a disadvantage that the drive circuit cannot be made smaller and thinner.

In the circuit configuration of an EL driver according to the prior art for a liquid crystal display device such as a watch, for example, an inductance element that controls the size of circuit mounting is indispensable, and the whole tends to be large. In addition, the function is limited to EL driving. For example, in order to add a function of driving a sounding body, a sounding body and a driving circuit of the sounding body must be provided separately, and a small and thin body is required. I couldn't. An object of the present invention is to eliminate the above-mentioned drawbacks and propose a configuration of a compact and thin EL driver circuit having a composite function capable of driving an electromagnetic sounding body in addition to EL driving and capable of being surface-mounted. Things.

[0006]

Means for solving the problem according to the present invention is to provide a boosting drive circuit for an EL light emitting substrate comprising electronic components such as a drive element including an active element, an inductance element and a chip capacitor. In an EL driver circuit having a composite function mounted on a substrate, a part of the electronic component is constituted by a driving coil of a sounding body connected to an amplifier circuit, and an EL lighting instruction and a sounding body sound are provided to the driving element. A command switching terminal is provided, and the sound pressure frequency band of the sounding body is effectively excluded from the frequency band of the step-up driving circuit for the EL light emitting substrate.

In order to solve the problem according to the present invention, the electronic component includes an inductance element formed of a drive coil of an electromagnetic sounding body, and the driving element is connected to the sounding body when the EL lighting command is on. It is characterized in that the connected amplifier is turned off.

[0008] Further, a means for solving the problem according to the present invention is that the inductance element of the electronic component is constituted by a drive coil of an electromagnetic sounding body, and the drive element emits the sound when the sounding body sound command is on. The amplifier connected to the body is turned on.

In order to solve the problem according to the present invention, the frequency band of the sounding body is set to 50 Hz to 15 Hz.
The frequency range is in the range of kHz.

[0010]

Embodiments of the present invention will be described below with reference to the drawings. FIG. 1 is a configuration diagram of an EL driver circuit block having a composite function according to the present invention. FIG.
FIG. 2 is a circuit block diagram of the EL driver when the electromagnetic sounding body of the present invention is silent. FIG. 3 is a band frequency diagram of the sound pressure of the electromagnetic sounding body of the present invention. FIG. 4 (A) shows E of the present invention.
FIG. 8B is a diagram for explaining a sounding command signal of the L driver circuit, and FIG. FIG. 5 is a configuration diagram of an EL driver circuit block when the electromagnetic sounding body of the present invention sounds.

In FIG. 1, in a circuit block 100 of an EL driver, electronic components such as a drive coil 132 of an electromagnetic sounding body 111 and a chip capacitor 117 are determined in advance on a circuit board in place of an inductance element according to specifications. Driving device (IC) including active device having terminal
115 is connected as follows. The connection terminal 114 of the input power supply voltage VDD is connected to the terminal 12 of the driving element 115.
3, the terminal 129 of the drain-source voltage VDS is connected to the terminal 128 of the driving element 115 via the driving coil 132.
Connected to. The sounding body input terminal 112 is provided on the base.
Is connected to a terminal 128 of the driving element 115, and an emitter of the transistor 113 is connected to the ground. EL / sounding body switching signal input terminal (hereinafter, signal switching terminal) 118 is a terminal 1 of driving element 115
25, the chip capacitor 117 is connected to the terminals 126 and 127 of the driving element 115, the ground terminal 124 of the driving element 115 is appropriately connected to the ground, and the output terminals 119 and 120 of the driving element 115 are connected to the input terminal 1 of the EL substrate 116.
21, 122.

In FIG. 2, when an EL lighting command is input to the signal switching terminal 118, the base 112 of the transistor 113 is in a low circuit configuration as shown by a dotted line, and the transistor 113 is turned off, The drive coil 132 of the expression speaker 111 is directly connected to the drive element 115. 6 of the related art has an inductance value of about 2.5 mH and a DC resistance value of about 60 ohms. The inductance value of the electromagnetic speaker of the embodiment of the present invention is about 0.6 to 10 mH, and Resistance value 10
~ 100 ohms. This indicates that the inductance value and the resistance value of the inductance element and the electromagnetic sounding body 111 are almost the same.

In FIG. 3, the sound pressure frequency characteristics of the electromagnetic sounding body 111 are shown as an input voltage of 2 to 20 V and a current of 10 to 100 m.
Although the sound pressure changes in the range of A, the frequency characteristics hardly change, and it is shown that the sound pressure is within the range of approximately 50 Hz to 10 kHz within the audible frequency range. Therefore, if the driving frequency of the EL substrate 116 is equal to or higher than 15 kHz, the electromagnetic sounding body 111 does not substantially sound but behaves only as an inductance element.

The sounding body sounding command signal 13 shown in FIG.
1 is input to the signal switching terminal 118 in FIG.
1B is input to the base 112 of the transistor 113 shown in FIG. 1, and the base 112 of the transistor 113 has a high circuit configuration. The transistor 113 is turned on, and the electromagnetic speaker 111 sounds.

In FIG. 5, when the electromagnetic sounding body 111 is sounding, as shown by the dotted line, the driving element 115 is driven.
, The EL substrate 116 does not light up, and the electromagnetic sounding body 111 continues to sound for a fixed time.

In the embodiment of the present invention, the driving frequency of the EL substrate 116 is 15 kHz or more, and the band frequency of the electromagnetic sounding body is 10 kHz or less. There is no sound. In addition, since the inductance value and the resistance value of the conventional inductance element and the drive coil of the electromagnetic sounding body can be set to values that are substantially similar, the illuminance during EL lighting can be made substantially the same.

[0017]

According to the present invention, since the driving coil of the electromagnetic sounding body is used instead of the inductance element of the EL driver circuit, the arrangement of the inductance element can be omitted from the EL driver circuit, so that the EL driver circuit is mounted. The resulting circuit board is further reduced in size and thickness, and is effective for surface mounting as a whole as one electronic component.

Further, according to the present invention, the driving frequency of the EL driver circuit is set outside the band frequency of the electromagnetic sounding body, so that the sounding of the electromagnetic sounding body is practically nonexistent, and the illuminance when the EL is turned on is low. Sufficiently secured.

[Brief description of the drawings]

FIG. 1 is a configuration diagram of an EL driver circuit block having a composite function according to the present invention.

FIG. 2 is a circuit block diagram of an EL driver when the electromagnetic sounding body of the present invention has no sound.

FIG. 3 is a band frequency diagram of the sound pressure of the electromagnetic sounding body of the present invention.

FIG. 4A is an explanatory diagram of a sounding command signal of the EL driver circuit of the present invention, and FIG. 4B is an explanatory diagram of a sounding body sounding signal.

FIG. 5 is a configuration diagram of an EL driver circuit block when the electromagnetic sounding body of the present invention sounds.

FIG. 6 is a typical circuit block diagram of a conventional EL driver.

[Explanation of symbols]

 REFERENCE SIGNS LIST 100 EL driver circuit block 111 electromagnetic sounding body 112 sounding body input terminal 113 sounding body drive transistor 114 connection terminal of input power supply voltage 115 drive element 116 EL substrate 117 chip capacitor 118 EL / sounding body signal switching terminal 124 ground terminal 130 sounding Body sound signal 131 Sound body sound command signal 132 Drive coil

──────────────────────────────────────────────────続 き Continued on the front page (51) Int.Cl. ⁶ Identification symbol FI // G09G 5/00 510 G09G 5/00 510Q

Claims (4)

[Claims] 1. An electronic device such as a driving element including an active element, an inductance element, and a chip capacitor.
An EL driver circuit having a composite function in which a step-up driving circuit for an L light emitting substrate is mounted on a circuit board, wherein a part of the electronic components is constituted by a driving coil of an electromagnetic sounding body connected to an amplifier circuit; A switching terminal for an EL lighting command and a sounding body sounding command is provided in the driving element, and the sound pressure frequency band of the electromagnetic sounding body is effectively excluded from the frequency band of the step-up driving circuit for the EL light emitting substrate. An EL driver circuit having a complex function. 2. An electronic device comprising: an inductance element of an electronic component comprising a drive coil of an electromagnetic sounding body;
2. The EL driver circuit having a combined function according to claim 1, wherein the amplifier connected to the sounding body is turned off when the lighting command is turned on. 3. An electronic device, wherein the inductance element of the electronic component comprises a drive coil of an electromagnetic sounding body, and the amplifier connected to the sounding body is turned on when the driving element is in a sounding body sounding command. The EL driver circuit having a composite function according to claim 1, wherein: 4. The frequency range of the electromagnetic sounding body is 50H.
2. The frequency range of z to 15 kHz.
An EL driver circuit having the composite function described in the above.