JPS6013154B2 - Crystal clock motor drive circuit - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a motor drive circuit for a quartz watch.

Conventionally, in the motor drive circuit of a quartz watch, the crystal oscillator load capacitor (capacitor) and oscillation integrated circuit are each independent, so even if the frequency of the quartz oscillator is adjusted, when each component is attached to the circuit board, floating occurs. The oscillation frequency shifts due to the influence of capacitance.

Therefore, it was necessary to insert a trimmer capacitor to adjust the frequency. The present invention eliminates the drawbacks of the prior art described above,
It is an object of the present invention to provide a motor drive circuit for a quartz watch in which there is almost no deviation in oscillation frequency after frequency adjustment.

An embodiment of the present invention will be described based on the drawings. As shown in FIG. 1, the inside of a metal base 1 is filled with airtight glass 2, and two terminal pins 3 and 4, which are external terminals, are installed as a shield. .

A circuit board 5 is erected on the base 1 by the terminal pins 3 and 4. Therefore, the specific configuration of the circuit board 5 is as follows.
The manufacturing process will be explained based on FIGS. 2A to 2C. The material of the circuit board 5 is non-conductive, such as glass, epoxy resin, Bakelite, etc., and the circuit board includes two base electrode films 6, 7 and their lead electrodes 6a, 7a, a ground electrode film 8, and an integrated circuit board. Electrode film 9 for die bonding a circuit Other circuit patterns 10, 11
form. Next, on the top surface of each base electrode film 6, 7,
As shown in Figure 2B, a dielectric film 12 is formed by vapor deposition of silicon monoxide, etc., except for both outer sides of this electrode film. Further, as shown in FIG. 2C, an outer electrode film 13 is deposited on the upper surface of the dielectric film 12 so as not to contact the exposed base electrode films 6 and 7, and this outer electrode film is used to connect the ground electrode film 8 and the die. It is electrically connected to the electrode film 9 for bonding. In this way, the circuit board 5 has the dielectric film 12 interposed between the base electrode films 6 and 7 and the outer electrode film 13 to form a load capacitance. Note that since the outer electrode film 13 only needs to be electrically conductive, the film thickness may be very thin. An integrated circuit (IC chip) 14 is firmly fixed on the top surface of the die bonding crab gokoku 9, and includes extraction electrodes 6a, 7a of the base electrode films 6, 7, the die bonding electrode film 9, and circuit patterns 10, 11. are connected to each circuit element of this IC chip by wire. Note that the terminal pins 3 and 4 are electrically connected to the circuit patterns 10 and 11 of the circuit board 5, respectively. By the way, on the base electrode films 6 and 7 exposed on the surface of the circuit board 5, conductive holding springs 15 and 15 are provided oppositely to each other so as to be electrically conductive with the base electrode films. There are various shapes of the holding spring 16, but as shown in FIGS. 3A to 3C, the holding springs 15a, 5b, and wings 5c are bonded and fixed to the rising pieces 16a, 16b, and 16c, respectively, and the circuit board 5. Joint piece 17a, also 7b? 17c is formed. The rising pieces 16a, 16b, 16c have competitive grooves 18a, 18 for competitively fixing the outer edge of the crystal resonator.
b, 18c are drilled. Therefore, as shown in FIG. 4, the crystal resonator 19 is held substantially parallel to the circuit board 5 with a gap therebetween by a holding spring 15. Drive electrode films 20 and 21 (not shown) are formed on both sides of the crystal resonator 19, and the respective lead electrodes 20a and 21a are drawn out in opposite directions and electrically connected to the holding springs 15 and 15. , are fixed with conductive adhesive. Therefore, by fitting the lower end of the metal cap 22 to the metal base 1, the circuit board 5 and the crystal resonator i9 are hermetically sealed. By the way, as shown in the first and fifth figures, there are holding plates 23, 23 which hold the ground electrode film 8 of the circuit board 5 and are elastically joined to the inner surface of the cap 22. The upper end of the circuit board 5 is held in a predetermined position by the holding plate 23, which not only cushions the impact caused by external force but also protects the metal cap 22.
The outer electrode film 13 of the load capacitor is electrically connected to the outer electrode film 13 of the load capacitor via the earth electrode film 8 of the circuit board. Next, the electrical connection state of the present invention will be explained with reference to the equivalent circuit diagram shown in FIG.

Terminal pin 4 is an output terminal for driving a clock, and electrode 11
It is wire-bonded to the clock drive circuit 24 of the IC chip 14 via. 25 is a frequency dividing circuit, 26 is a buffer, and 27 is an amplifier.

The metal cap 22 is connected to a holding plate 23 to be grounded, and the holding plate 23 and the grounding electrode film 8 are connected to each other.
, the outer electrode film 13 is connected to the IC chip 14 via the die-ponding electrode film 9.Next, the driving state of the timepiece by the crystal oscillator according to the present invention will be explained with reference to FIG. 7.Inductor Drive coil 28 of motor M
A capacitor 29 is connected in series with the IC.
A DC fin source 30 is connected in series through a switching circuit in the drive circuit 24 of the chip 11. Therefore, a current is passed in one direction through the drive coil 28, and the capacitor 29 is charged, and the capacitor is discharged by switching the switching circuit, and a current is made to flow in the other direction through the drive coil. In this way, the driving inductor motor M is rotationally driven. The present invention having the above configuration has the following features: - The load capacitor is formed on the circuit board and hermetically sealed together with the integrated circuit for disturbance in one cap, and furthermore, the clamping plate is the load capacitor formed on the inner surface of the metal cap and the circuit board. Since the outer electrode knee of the capacitor is electrically connected, this metal cap and this outer electrode film are grounded to the same potential, and as a result, there is no deviation in the oscillation frequency due to the influence of stray capacitance. In addition, since the area of the load capacitance can be configured wide, the capacitance can be increased, and since the load capacitance is hermetically sealed, the load capacitance is not affected by temperature, increasing reliability. do not need. In addition, a fall fin plate is provided that holds the circuit board and is elastically bonded to the inner surface of the cap, allowing the cap to be used as an external terminal.Furthermore, since the circuit board is held in place, it is protected from shocks caused by external forces. earthquake resistance is improved. Furthermore, since the number of parts is very small, assembly is very simple and workability is excellent.

[Brief explanation of the drawing]

The drawings show an embodiment of the present invention, and FIG. 1 is a sectional view;
Figures 2A to 2C are plan views showing the order in which load capacitance is applied to the circuit board, Figures 3A to 3C are perspective views showing embodiments of the retaining spring, and Figure 4 is the same as the one shown in Figure 1. W-
5 is a sectional view taken along the line V--V in FIG. 1, FIG. 6 is an equivalent circuit diagram, and FIG. 7 is a wiring diagram of the drive circuit of the drive motor. 1...Metal base, 3...Output terminal for clock drive, 4...Power terminal, 5...Circuit board, 6
, 7... Base electrode film, 8... Earth electrode film,
9... Electrode film for die bonding, 10, 11
...Circuit pattern, 12...Dielectric film,
13... Outer electrode film, 14... Integrated circuit, 15... Holding spring 19... Crystal resonator, 22... Metal cap, 23...・・・・・・
Holding plate. Fig. 1 Fig. 2A Fig. 28 Fig. 2C Fig. 3A Fig. 38 Fig. 3C Fig. 4 Fig. 5 Fig. 6 Fig. 6 Koji

Claims (1)

[Claims] 1. A circuit board standing up on a base, an integrated circuit die-bonded on the circuit board,
A load capacitor formed on the circuit board, a crystal oscillator held in electrical continuity with the base electrode film of the load capacitor via a holding spring, a crystal oscillator fitted on the base, and a crystal oscillator fitted on the base and connected to the circuit board and the crystal oscillator. a metal cap hermetically sealed; and a clamping member that is in elastic contact with the inner surface of the metal cap to maintain a constant positional relationship of the circuit board with respect to the cap and electrically conductive between the metal cap and the outer electrode film of the circuit board. A motor drive circuit for a crystal clock, characterized in that it is composed of a plate and more.