JPS5944681A - Electronic clock - Google Patents

Abstract

PURPOSE:To drive a piezoelectric buzzer stuck directly to a metallic back cover in a push-pull mode without insulating between a case and a switch part, by providing a circuit for deciding the polarity of a signal inputted to a switching circuit. CONSTITUTION:One electrode of a piezoelectric buzzer is connected directly to a metallic back cover, and is driven in a push-pull molde. Therefore, the potential of a case repeats periodically Vdd and Vss. When a switch button is pushed when the piezoelectric buzzer is sounding, a switch spring is varied to VDD and VSS in accordance with its driving signal BZO, therefore, a switch input signal D becomes a shape taking AND of the driving signal BZO. A switch read control clock signal WS reads a signal BZ in an H period of a clock CL, and that which inverts it and the buzzer signal BZ are inputted to an NAND gate 3, therefore, when the switch is depressed for one period or more of WS, an FF1 decides that the fact is a switch input.

Description

[Detailed Description of the Invention] The present invention provides a sound generating device f (hereinafter abbreviated as an alarm device).
The present invention relates to a magnetic watch, and more particularly to a switch input determination method for an electronic watch with an alarm device, which has a pressure buzzer in which a pressure element is directly attached to a metal lid.

An object of the present invention is to simplify the structure of the switch input section of the electronic timepiece with an alarm device.

In recent years, electronic watches have become smaller and thinner.
Along with this, it has become necessary to review the relationship with alarm devices.

FIG. 1(a) shows a drive circuit for a piezoelectric buzzer commonly used at present, and FIG. 1(b) shows an example of a bush-pull drive circuit.

In FIG. 1(a), 1 is a piezoelectric element, 2 is a boosting coil, and 3 is a bipolar transistor for driving. In FIG. 1(b), 1 is a piezoelectric element, and 2 to 5 are for driving 10 built-in F Ej T (Field EffectTr
aneister), 2.4 FETs and 3.5
A driving signal with an opposite phase is applied to the gate of the FET.

As shown in Figure 1 (a), the current general drive system requires a boost coil and a bipolar transistor, which reduces the volume and cost (Figure 1 (1)).
The pull-pull drive system shown in Figure 3 is advantageous. Especially the boost coil O, even the smallest one has a diameter of 5 mm and a height of 2.5 mm.
Rin: To some extent, this is an obstacle to making watches smaller and thinner, but the Punyupuru drive method, which does not require this, can be said to be a very effective means.

However, in order to realize the bush-pull drive method, there is a problem with insulation in the structure of the switch button part.

In other words, as is clear from FIG. 1(b), in the bush-pull drive method, the potential across the piezoelectric element follows the drive signal as VDD ($-4) t lj, VBB
(Q potential) alternately. For this reason, in the case of a buzzer structure in which a piezoelectric element is attached to a metal back cover, the potential of the entire metal exterior case body changes periodically.

On the other hand, FIG. 2 is a sectional view of the switch button 7, (3).

In Figure 2, 1 is a switch button, 2 is a pipe N3
4 is a switch button fixing ring, 4 is a paragine, 5 is a switch spring, 6 is a circuit board, 7 is a contact on the circuit board, 8 is a piezoelectric element, and 9 is a contact spring. Normally, switch spring 5 is connected to VDII and is always in contact with the switch button. When switch button 1 is pressed, the switch spring is deflected and reaches the position shown by the dotted line 5' in the figure. , by energizing the contact 6 on the circuit board, it is recognized as a switch input. Therefore, if the switch button and pipe are made of metal,
The outer case body is grounded to VDD through the edge.

As described above, with this structure, it is not possible to periodically change the potential of the outer case body, so in order to perform pull drive, it is necessary to There was a core wall between them that had to be insulated in some way, which led to an increase in costs.

The present study aims to eliminate such problems and to develop a switch structure that enables bush-pull drive without increasing costs.
A switch input determination circuit is provided.

Hereinafter, a detailed explanation of the present invention will be added based on the drawings.

FIG. 3 is a sectional view of an example of the structure of the switch section according to the present invention.

In Figure 6, 1 to 9 are the same as those in Figure 2, and 10
These are metal fixing screws for fixing the switch spring 1d5 and the contact spring 9 to the circuit board, and at the same time ensuring electrical continuity with the wiring pattern on the circuit board. In this (4-structure), the switch spring is not insulated from the VDD wiring pattern on the circuit board, and is connected to one drive output of the bush-pull circuit in Fig. 1 (b), that is, to one side of the piezoelectric element, and by extension to the outer case. This structure solves the problem of insulation between the switch spring and the switch button, and between the switch button and the outer case body.On the other hand, with this structure, , When the piezoelectric buzzer is ringing, the potential of the switch spring is the same as that of the outer case body (F) and VDD and ■811+ are periodically repeated, so determining the switch input at that time becomes a problem, and the present invention solves this problem. The law also provides.

The method will be explained below.

FIG. 4 shows a specific example (a) of the switch input determination circuit according to the present invention, and a timing chart (b) at the time of switch input when the piezoelectric buzzer is ringing in the bush pull rA shift.
It is.

In FIG. 4, 1 is the mask slave W F/F (
Flip-flop L 2fi master type F'/F'.

3 is a two-man powered WAND gate, 4 is an inverter, (a)
The SW in is a switch, and its closing is the 6th
In the figure, the switch spring 5 contacts the contact point on the circuit board 7, and the SW in (b) is the period when the SW in (a) is closed. Other than that, it is expressed as "LO" (=vdayday). moreover,
The whiskers at both ends of the continuous "H" period are chattering due to the mechanical contacts. Also, 1
The number is the signal of the contact on the circuit board, and this is the actual switch input number. Signal AL indicates that the buzzer is ringing, and while the bell is ringing, it becomes "H Engineering J." Signal BZ indicates that No. 100 A
This is a signal that outputs a buzzer ringing signal when L is "H", and an arbitrary key signal for forming a signal WS to be described later.

Signal BZO is a drive signal that rings a piezoelectric buzzer, and when this is "H work", the outer case body becomes VDD.

The WS controls the reading of the switch and uses the self-turn signal.
- Signal SWQ is the output of the switch input determination circuit, and when this signal becomes "H", it is assumed that there is a switch input, and switch processing is performed.

Now, if the switch button is pressed while the pressure buzzer is ringing, the switch spring will respond to the VJ signal BZO.
DD, vss, the switch input signal is in the form of ANDing SW and drive signal BZO.
The timing chart (1)) shows this. Here, the switch read control clock signal WS is 20F
/ F makes No. 100 BZ clock OL's "H engineering"
It is read in the period of Always synchronized. Also, 1
Since the force signal RI is read and the judgment output SWQ is output from Q, if the switch SW is pressed for at least one cycle of WS, it is definitely judged as a switch input.

As described above, according to the present invention, by simply adding a simple Jφ circuit, a piezoelectric buzzer directly affixed to a metal back cover can be operated without a complicated insulation structure that increases costs.
Nibble drive becomes possible. ! ! *When the buzzer is not driven, turn on FETZ & 3 shown in Figure 1(b),
, 4 & 5 are turned off, and the outer case body feVDn
If it is made conductive, there will be no problem with the switch input when the buzzer is not driven, and by doing so, it will be resistant to malfunctions caused by the electromotive force of the piezoelectric element when the watch is dropped.

Furthermore, according to the present invention, since the buzzer drive signal and the switch read control clock signal are synchronized, this method is particularly effective for electronic watches that have sounds with varying drive frequencies, such as melodies or chime sounds with varying pitches. Demeru.

In addition, the method of forming the switch read clock signal is as follows:
The circuit is not limited to the circuit example shown in FIG. 4 as long as it is synchronized with the buzzer drive signal.

[Brief explanation of the drawing]

Figure 1... (&) Typical piezoelectric buzzer drive circuit value)
Example of a bush-pull drive circuit FIG. 2: Cross-sectional view of a switch button portion FIG. 3: Cross-sectional view of an example of the structure of a switch portion according to the present invention FIG. 4: (a) Specification of a switch input determination circuit according to the present invention Example (b) The above timing chart Applicant Suwa Seikosha Co., Ltd. Agent Patent attorney Mogami Bo-442 (α) (b) Home 1 day

Claims (1)

[Claims] In an electronic watch that includes a piezoelectric buzzer that can be activated by attaching a piezoelectric element to a metal back cover and setting the buzzer on a metal body, and a drive circuit that pushes and pulls and drives the piezoelectric buzzer, the switch spring and the metal body are A switch part is electrically conductive, and a clock signal for reading and controlling the switch is provided at least while the wake-up buzzer is ringing.
The number of percentages is 4, which is based on having a switch input judgment circuit that is synchronized with one sound that fully drives the recording pressure buzzer.
Child clock.