JPH0437609B2 - - Google Patents

Description

[Detailed description of the invention]

The present invention relates to an individual selective calling receiver having a ringing function, and more particularly to a driving circuit for a display unit and a sounding unit for an individual selective calling receiver, which has a function of transmitting information by a display as well as a sound. It is. Since individual selective calling receivers are generally used while being carried, progress has been made in making them smaller and lowering their power consumption. The receiving section can be operated with a single dry cell battery (1.0 to 1.5 V), and the sounding section uses an alarm phone that can be driven with a voltage of about 1 V from the dry cell battery. Further, as the display element of the display section, a liquid crystal display element is usually used especially from the viewpoint of low power consumption. However, in order to further reduce the size and power consumption of the sounding section, it is possible to use a piezoelectric buzzer instead of the alarm phone. Table 1 shows a comparison of the current consumption of small alarm phones and piezoelectric buzzers.

[Table] Furthermore, when using a liquid crystal element in the display section, since the liquid crystal itself does not emit light, it is difficult to obtain a clear display in dark places such as at night. It is used. However, when the miniature light bulb is used, since light is applied from the outer periphery of the display element, the brightness on the display surface becomes uneven, making it difficult to read. small size,
Electroluminescence or electroluminescence is used as a display backlight element that satisfies the requirements for low power consumption and provides clear display.
The use of Luminescence (EL) elements is considered. However, when using the piezoelectric buzzer and EL element, there was a problem with the driving voltage. That is,
Even if recent low-voltage, high-brightness ELs are used to drive EL elements, AC of several hundred to several KHz is required.
A voltage of 35 to 60 V is required, and a voltage of 4 to 10 several KHz is required to drive the piezoelectric buzzer. On the other hand, the receiving section uses a low bias voltage type circuit, and only uses a single dry cell battery as a power source. Therefore, in order to drive the piezoelectric buzzer and the EL element, a drive circuit using a booster coil is required. However, in this case, the frequency for driving the boost coil is low, around 2KHz, so a relatively large coil is required to obtain sufficient voltage to drive the piezoelectric buzzer and boost coil. Providing such large booster coils separately for driving the piezoelectric buzzer and for driving the EL element has the disadvantage of being a major inconvenience due to the need to miniaturize the device. The present invention uses a tap in the middle of the boost coil to share the drive circuit for the piezoelectric buzzer and EL element, reducing the number of components in the drive circuit, resulting in a compact, low power consumption system.
Moreover, an individual selective call receiver with a display that can provide a clear display regardless of whether it is a bright place or a dark place can be obtained. According to the present invention, as a light source for illuminating the display section.
A display selection call receiver is provided, which includes an EL element, a piezoelectric buzzer as a sounding body of a sounding part, and a drive circuit having a boost coil and shared for driving the EL element and the piezoelectric buzzer. It will be done. Next, embodiments of the present invention will be described with reference to the drawings. FIG. 1 is a block diagram of a conventional selective call receiver with display, and FIG. 2 is a block diagram of a selective call receiver with display according to the present invention. FIG. 3 is a time chart of waveforms of various parts in the embodiment of the present invention.
Further, the boost coil section is shown separately in FIG. The following description will be made with reference to these drawings. First, the operation of a conventional selective call receiver with display will be explained. When a signal is received by the antenna 1, it is sent to a receiving section 2 including an amplifying section and a demodulating section.
The output from the receiving section 2 includes an individual calling number and calling information. When this is sent to the calling number comparison unit 3, it is compared with the receiver's own number stored internally, and if they match, the calling information is stored in the calling information storage unit 4, and at the same time the ringing An output command is sent to the output control section 5. A timer included in the output control section 5 and an external switch 6 control whether the contents stored in the call information storage section 4 are displayed on the call information display section 7 or whether a sound is emitted. The calling number comparison section 3, the calling information storage section 4, the output control section 5, and the external switch 6 are realized by a ``wireless selective calling receiver equipped with a display device'' (Utility Application No. 51687/1987). From the output control unit 5, an intermittent ringing signal as shown in FIG. 3A and a call information display signal corresponding to the received call information content as shown in FIG. 9 BCD is shown)
is output. The sound signal is generated by controlling a frequency dividing circuit 9 that divides the signal from the oscillator 8 into audio frequencies.
An intermittent sound is output to the speaker 10. On the other hand, the call information display signal is sent to the call information display section 7 and displayed. Further, a miniature light bulb 11 is used for illuminating the display section, and is turned on and off (ON-OFF) by a push switch 12. In addition,
The battery 13 is used as a common power source for this receiver. On the other hand, the selective call receiver with display according to the present invention will be explained with reference to FIG. In Figure 2, 1 to 4
and 6 and 7 have exactly the same configuration as the one in FIG. 1, and operate in the same way. In addition to the intermittent sound signal A and the call information signal B described in the explanation with reference to FIG. , a continuous signal D is output. The signals C and D are sent to the OR gate 15, and either the signal C or the signal D is logic "1" (high level).
In the state of , the output of the OR gate 15 becomes high level. In particular, the signal D is turned on and off by the push switch 12, and is transmitted to the OR gate 15 only when the EL element is lit. This output is the audio frequency (e.g. 2KHz)
The signal E is sent to the AND gate 17 together with the output of the oscillator 16 which oscillates the signal E. The configuration using the oscillator 16 and the AND gate 17 has the same function as the configuration using the oscillator 8 and frequency dividing circuit 9.
The temporal relationship between the signals A to E and the signal F, which will be described later, is as shown in FIG. The signal E causes the switching transistor 18 to
When the voltage is interrupted, a back electromotive current is generated in the boost coil 19 due to rapid fluctuations in the collector current flowing at that time. Regarding the booster parts 18 and 19, the fourth
Shown in the figure. The back electromotive current generated in the boost coil 19 is proportional to the temporal fluctuation of the collector current of the switching transistor 18 and the inductance of the boost coil 19. That is, if the rising time of the switching transistor 18 during switching is t, and the inductance of the boosting coil 19 is L, then L/t
is proportional to. By selecting this appropriately, it is possible to obtain an AC voltage of 40V across the entire boost coil. The 40V generated in this boost coil remains as it is.
This is used as the voltage for driving the EL element, and by taking an intermediate tap at the turn ratio m:n=4:1 as shown in FIG. 4, it is possible to obtain a piezoelectric buzzer driving voltage of 10V. The voltage of 40V boosted by the boosters 18 and 19 is supplied to the EL element 22 via a push switch 23 linked to the push switch 12. On the other hand, the 10V taken out from the intermediate tap
The voltage is interrupted in the switching circuit 20 by the sound intermittent signal A, and a signal having the pattern shown in F in FIG. 3 is supplied to the piezoelectric buzzer 21 to generate a sound. The switching circuit 20 can be realized by a general analog switch. According to the present invention, as explained above, EL
By sharing the boost coil for driving the element and the piezoelectric buzzer, the circuit is simplified and a small, low power consumption type that can provide clear display regardless of bright or dark places. You can get a selective call receiver with display.

[Brief explanation of drawings]

Fig. 1 is a block diagram of a conventional selective call receiver with display, Fig. 2 is a block diagram of an embodiment of the present invention, Fig. 3 is a time chart of waveforms of various parts in an embodiment of the present invention, and Fig. 4 is a booster. FIG. 3 is an example circuit diagram of a circuit section. In the figure, 1... Antenna, 2... Receiving section, 3... Calling number comparison section, 4... Calling information storage section, 5, 14...
Output control section, 6... External switch, 7... Calling information display section, 8, 16... Oscillator, 9... Frequency dividing circuit, 10...
Speaker, 11... Mini light bulb for lighting, 12, 23... Push switch, 13... Battery, 15... OR gate, 17... AND gate, 18... Switching transistor, 19... Boost coil, 20... Switching circuit, 21... Piezoelectric Buzzer, 22... is an EL element.

Claims (1)

[Claims] 1 a first means for detecting a paging signal assigned to the local station from a received signal and generating first and second control signals in response to this detection; and a first means for generating first and second control signals in response to the detection; A power supply voltage boosting coil that is continuously driven for a period of time, and an EL as a light source for illuminating the display unit that receives a first boosted voltage from the power supply voltage boosting coil and is driven by the first boosted voltage.
(Electric Luminescence) element and a second boosted voltage lower than the first boosted voltage is supplied from an intermediate tap between the power supply voltage boosting coil and is used as a sounding body of a sounding section that is driven by the second boosted voltage. a piezoelectric buzzer; and second means for intermittently driving the piezoelectric buzzer in a predetermined pattern for a predetermined period of time in response to the second control signal.