JP2006025336A - Piezoelectric oscillator and adjustment method thereof - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To solve problems of sacrificing a fault diagnostic function because there is no space margin for a package of a piezoelectric oscillator the downsizing of which is a requirement resulting in that provision of a measurement terminal exclusively for a crystal vibrator is impossible and of a low manufacturing efficiency because data of the piezoelectric oscillator single body cannot be confirmed after the mount of the crystal vibrator due to the absence of the measurement terminal resulting in that adjustment procedures of writing temperature compensation data to the oscillator are complicated. <P>SOLUTION: The piezoelectric oscillator is provided with: a piezoelectric vibrator; an oscillation circuit; a package including input output terminals and an adjustment terminal; first switching means inserted between the piezoelectric vibrator and the oscillation circuit; and second switching means inserted between the piezoelectric vibrator and the input output terminals. The first switching means set the connection between the piezoelectric vibrator and the oscillation circuit to either an interruption state or a conductive state on the basis of a selection signal, and the second switching means set the connection between the piezoelectric vibrator and the input output terminals to either a conductive state or an interruption state. <P>COPYRIGHT: (C)2006,JPO&NCIPI

Description

  The present invention relates to a piezoelectric oscillator and a method for adjusting the same.

A crystal oscillator is a piezoelectric oscillator that uses a crystal resonator as a piezoelectric element, and is widely used as an oscillation source having a highly stable reference frequency.
In particular, the demand for a temperature-compensated crystal oscillator (TCXO) having a temperature compensation circuit therein and stabilizing frequency temperature characteristics is particularly high. In recent years, due to a demand for miniaturization of a temperature compensated crystal oscillator (TCXO), an IC (TC-integrated TCXO) in which a temperature compensation circuit other than a crystal resonator and peripheral circuits are all integrated into one IC has become mainstream.

  Conventionally, a temperature-compensated crystal oscillator requires adjustment for writing temperature compensation data, but generally includes the following adjustment procedure. First, before mounting on a package, a crystal unit is placed in a thermostatic chamber, and frequency temperature characteristic data is acquired. Next, temperature compensation data is created from the frequency temperature characteristic data of the single crystal unit, the crystal unit is mounted in a package together with an IC, and the package is sealed. Then, the temperature compensation data is written from the write terminal of the package, the crystal oscillator is put in a thermostatic chamber, the frequency temperature characteristic is confirmed, and the adjustment is completed.

Here, since the frequency temperature characteristics of the crystal unit itself may change before and after mounting on the package, only the crystal unit is mounted on the package and this is placed in a thermostat to acquire the single unit data. In some cases, temperature compensation data is created from single data and an IC is mounted later. However, once the crystal unit and the IC are mounted on the package, they are electrically connected to each other. Therefore, in this state, the data of the crystal unit or the fault diagnosis is obtained. The characteristics of a single crystal unit cannot be confirmed.
Therefore, when some trouble such as a failure occurs in the crystal oscillator, it is difficult to easily determine whether the cause is on the crystal oscillator side or on the peripheral circuit side.
In addition, with the recent miniaturization of crystal oscillators, it has become very time consuming and difficult to perform fault diagnosis by removing the crystal resonator from the package. Japanese Laid-Open Patent Publication No. 9-246868 discloses a method for performing fault diagnosis by immediately confirming the characteristics of a crystal unit without replacing the crystal unit while it is mounted.

FIG. 5 shows a block diagram of the crystal oscillator disclosed in Japanese Patent Laid-Open No. 9-246868. The conventional crystal oscillator shown in FIG. 5 has an oscillation circuit 1, a crystal resonator 2, a power supply terminal 3, a ground terminal 4, an output terminal 5, and connection terminals 6, 7, and 8 and is entirely sealed in a metal case. The crystal oscillator module 9, the analog switch 10, the crystal oscillator 11 having the same characteristics as the crystal oscillator 2, the crystal oscillator module 9, the analog switch 10, and the second crystal oscillator 11 are mounted. And a printed circuit board 12.
Here, wiring patterns 13a, 13b, 13c, and 13d for mounting and connecting these components are formed on the printed circuit board 12.

The conventional crystal oscillator shown in FIG. 5 operates as follows.
First, it is assumed that the crystal oscillator shown in FIG. 5 has failed for some reason (for example, the oscillation is stopped). Therefore, when the selection signal is set so that the terminals 11b and 11c of the analog switch 10 are conducted, the connection between the connection terminal 6 and the connection terminal 8 is cut off, and the crystal resonator 2 is separated from the oscillation circuit 1. In addition, the crystal unit 11 is connected to the oscillation circuit 1 through the analog switch 10.
Therefore, the signal output to the output terminal 5 is checked, and if a predetermined oscillation signal is output from the output terminal 5, the cause of the oscillation stop is on the crystal resonator 2 side, and the oscillation is stopped. If there is, it can be diagnosed that the cause of the oscillation stop is the oscillation circuit 1 side.

Here, the crystal unit 11 is a component necessary only for failure diagnosis, and only a wiring pattern for mounting may be formed on the printed circuit board 12, and this may be mounted only when a failure occurs. For example, in a state where the crystal resonator 11 is not mounted, the terminals 11b and 11c of the analog switch 10 are set to be conductive, and the crystal resonator 2 is separated from the peripheral components. Therefore, if a measuring device such as a network analyzer is connected to the connection terminals 7 and 8, the characteristics of the crystal unit 2 alone can be confirmed.
When this is manufactured as a temperature-compensated crystal oscillator, the frequency temperature characteristic data of the single crystal unit 2 is acquired and the temperature compensation is performed from the frequency temperature characteristic data of the single crystal unit 2 as in the above-described example. It is necessary to make adjustments such as creating data and writing it to the oscillation circuit 1, but by using the connection terminals 7 and 8, it is possible to acquire single frequency temperature characteristic data even after the crystal resonator 2 is mounted. Has advantages.
Japanese Patent Laid-Open No. 9-246844

However, the conventional crystal oscillator shown in FIG. 5 has the following problems.
That is, this crystal oscillator has the advantage that even after the crystal resonator 2 is mounted, the data of the crystal resonator alone can be confirmed or acquired by connecting a measuring device such as a network analyzer to the connection terminals 7 and 8. When downsizing is required (especially IC TCXO), there is no room in the package, and thus such connection terminals cannot be provided. Therefore, in order to reduce the size, the function of confirming the characteristics of the crystal unit alone must be sacrificed.

  In addition, a conventional IC TCXO (quartz oscillator) that is required to be miniaturized prepares temperature compensation data from the adjustment work of acquiring a frequency temperature characteristic data by storing a crystal unit alone in a thermostatic chamber. Because adjustment work, assembly work for mounting crystal units and ICs in the crystal oscillator package, and adjustment work for writing temperature compensation data to the crystal oscillator must be executed in sequence, the adjustment work is interrupted However, the production efficiency will deteriorate. In addition, equipment for storing a crystal unit in a thermostat and acquiring frequency temperature characteristic data for the single unit, and equipment for storing a crystal oscillator in a thermostat after writing temperature compensation data and checking the frequency temperature characteristics Since it is necessary to prepare these separately, the manufacturing space of the factory is occupied, which is not preferable in manufacturing.

  The present invention has been made in order to solve the above-mentioned problems, has an adjustment procedure with high manufacturing efficiency, and can easily separate a single crystal unit and check its characteristics even when a defect occurs, and can be downsized. An object of the present invention is to provide a piezoelectric oscillator capable of satisfying the requirements.

  In order to solve the above-mentioned problem, in the invention described in claim 1, the piezoelectric vibrator, the oscillation circuit, an input / output terminal for inputting or outputting a signal, and an adjustment terminal are provided. A first housing that is inserted between the piezoelectric vibrator and the oscillation circuit, and a second switching means that is inserted between the piezoelectric vibrator and the input / output terminal. Wherein the first switching means sets the connection between the piezoelectric vibrator and the oscillation circuit to a disconnected state or a conductive state based on a selection signal input to the adjustment terminal. The second switching means sets the connection between the piezoelectric vibrator and the input / output terminal to either a conductive state or a disconnected state based on the selection signal.

  According to a second aspect of the present invention, in the piezoelectric oscillator according to the first aspect, the second switching means is inserted between the first switching means and the input / output terminal, Based on a selection signal, the connection between the piezoelectric vibrator and the input / output terminal is set to either a conductive state or a disconnected state via the first switching means. According to a third aspect of the present invention, in the piezoelectric oscillator according to the first or second aspect, the input / output terminal is any one of a power supply terminal, a ground terminal, a frequency control terminal, and an oscillation signal output terminal. It is.

  According to a fourth aspect of the present invention, in the piezoelectric oscillator according to the first, second, or third aspect, the oscillation circuit, the piezoelectric vibrator, the first switching unit, and the second switching unit. Are integrated in an IC chip. According to a fifth aspect of the present invention, in the piezoelectric oscillator according to the first, second, third, or fourth aspect, the oscillation circuit includes storage means for storing temperature compensation data; And a temperature compensation circuit for performing temperature compensation based on the temperature compensation data stored in the storage means.

  According to a sixth aspect of the present invention, in the piezoelectric oscillator according to the fifth aspect, the package includes a write terminal for inputting the temperature compensation data from the outside and writing it into the storage means.

  According to a seventh aspect of the present invention, in the piezoelectric oscillator according to the sixth aspect, an adjustment step of storing the piezoelectric vibrator in a thermostatic chamber, a selection signal is input to the adjustment terminal, and the first switching means is An adjustment step for setting the second switching means to the conductive state, and connecting the measuring device to the input / output terminal and changing the temperature in the thermostat to change the temperature-temperature characteristic data of the piezoelectric vibrator alone An adjustment step of acquiring temperature compensation data from the acquired frequency temperature characteristic data of the single piezoelectric vibrator, and an adjustment of inputting the temperature compensation data to the write terminal and writing it to the storage means And a step.

  The piezoelectric oscillator according to the present invention includes a piezoelectric vibrator, an oscillation circuit, a package having an input / output terminal, a first switching means inserted between the piezoelectric vibrator and the oscillation circuit, the piezoelectric vibrator and the front And a second switching unit inserted between the input output terminal and the first switching unit. The first switching unit connects the piezoelectric vibrator and the oscillation circuit based on the input selection signal. The second switching means sets the connection between the piezoelectric vibrator and the input / output terminal based on the selection signal in a conductive state or a disconnected state. It is set to either. Therefore, according to the present invention, it is possible to check the frequency temperature characteristics and data of the piezoelectric vibrator alone after mounting the piezoelectric vibrator, and to easily check the characteristics of the piezoelectric vibrator alone in the mounted state even when a failure occurs. An object of the present invention is to provide a piezoelectric oscillator capable of performing failure diagnosis in a short time and having good manufacturing efficiency and capable of being downsized.

The present invention will be described based on the embodiments shown in the drawings.
FIG. 1 shows a block diagram of a first embodiment of a piezoelectric oscillator according to the present invention.
1, the piezoelectric oscillator of the present invention includes a power supply terminal 14, a frequency control terminal 15, a ground terminal 16, an output terminal 17, a write terminal 18, and an adjustment terminal 19, a package 20, a crystal resonator 21, and a temperature compensation. An oscillation circuit 22 having a circuit, storage means 23 for storing temperature compensation data input from the write terminal 18, and inserted between the crystal resonator 21 and the oscillation circuit 22 and input to the adjustment terminal 19 First switching means 24a and 24b for switching connection based on a selection signal, and a second switching unit which is inserted between the crystal resonator 21 and the power supply terminal 14 and the frequency control terminal 15 to switch connection based on the selection signal. Switching means 25a, 25b, the oscillation circuit 22, the storage means 23, the first switching means 24a, 24b, and the second switching means 25a, 25b, It is integrated in the C26. Further, the IC 26 and the crystal resonator 21 are mounted on a package 20, and the entire package 20 is sealed.

The piezoelectric oscillator shown in FIG. 1 operates as follows.
First, the Hi voltage of the CMOS interface is input to the adjustment terminal 19 as a selection signal. (This state is hereinafter referred to as “oscillator mode”.) At this time, the first switching means 24a and 24b are connected as shown in FIG. 2A in accordance with the selection signal, and the crystal resonator 21 and the oscillation circuit 22 are connected. It becomes a state. Further, according to the selection signal, the second switching means 25a and 25b are connected as shown in FIG. 2A, the power supply terminal 14 is connected to the oscillation circuit 22 and the storage means 23, and power is supplied. The control terminal 15 is connected to the oscillation circuit 22.
Therefore, in this state, the oscillation circuit 22 is activated and an oscillation signal is output to the output terminal 17. In general, it is used in this state, and the frequency control terminal 15 is used as a terminal for inputting a DC voltage or a frequency modulation signal in order to control the frequency of the oscillation signal.

Next, the Lo voltage of the CMOS interface is input to the adjustment terminal 19 as a selection signal.
(Hereinafter, this state is referred to as “vibrator mode”.) At this time, the first switching means 24 a and 24 b are connected as shown in FIG. The connection is broken. Further, according to the selection signal, the second switching means 25a, 25b are connected as shown in FIG. 2B, the connection between the oscillation circuit 22, the storage means 23 and the power supply terminal 14 is cut off, and the crystal resonator 21 is The power supply terminal 14 and the frequency variable terminal 15 are connected. That is, the crystal resonator 21 is disconnected from the oscillation circuit 22 and connected to the power supply terminal 14 and the frequency control terminal 15.
Therefore, a measurement device such as a network analyzer is connected to the power supply terminal 14 and the frequency control terminal 15 to check the data of the crystal unit 21 alone. Since the first switching means 24a, 24b and the second switching means 25a, 25b do not operate unless power is supplied to the power supply terminal 14, a bias T circuit or the like is provided between the power supply terminal 14 and the measuring device. Insert it so that it can supply power.

In this way, by inputting a predetermined selection signal to the adjustment terminal 19 and changing the setting from the “oscillator mode” to the “vibrator mode”, the crystal resonator 21 can be easily disconnected from the oscillation circuit 22 and the crystal resonator The power supply terminal 14 and the frequency control terminal 15 can be used as the 21 measurement terminals. Further, it is not necessary to separately provide a connection terminal dedicated to the crystal unit for failure diagnosis in the package 20, and it is possible to reduce the size. Although the power supply terminal 14 and the frequency control terminal 15 are used as the measurement terminals of the crystal resonator 21, the present invention is not limited to this. For example, the ground terminal 16 and the output terminal 17 may be connected as measurement terminals, or two of these input / output terminals that are optimal as measurement terminals are considered in consideration of the wiring pattern. You may choose one.
Further, a wiring pattern connected to the adjustment terminal 19 in the IC 26 may be pulled up to a power source through a resistor. In this way, when the adjustment terminal 19 is opened, the piezoelectric oscillator of the present invention enters the “oscillator mode”, and when the adjustment terminal 19 is grounded, the “oscillator mode” is entered. Needless to say.

Next, a second embodiment of the piezoelectric oscillator according to the present invention will be described.
FIG. 3 shows a block diagram of a second embodiment of the piezoelectric oscillator according to the present invention.
The piezoelectric oscillator shown in FIG. 3 is different from that of the first embodiment shown in FIG. 1 only in the arrangement of the second switching means 25a and 25b, and the other configurations are completely the same. In the second embodiment shown in FIG. 3, the second switching means 25a is inserted between the first switching means 24a and the power supply terminal 14, and the second switching means 25b is connected to the first switching means 25b. It is inserted between the frequency control terminal 15. Since the operation is the same as that of the first embodiment described above, a detailed description is omitted. However, if the Hi voltage of the CMOS interface is input to the adjustment terminal 19 or is opened, the first switching means 24a, 24b and the second switching means 25a, 25b are connected as shown in FIG. 4A and are set to the “oscillator mode”. When the voltage of Lo of the CMOS interface is input to the adjustment terminal 19 or is grounded, the first switching means 24a and 24b and the second switching means 25a and 25b are connected as shown in FIG. “Transducer mode” is set. As described above, in the first and second embodiments described above, the arrangement of the first and second switching means and the connection state thereof are shown. The crystal resonator 21 is separated from the oscillation circuit 22, As long as it is connected to the input / output terminal, the arrangement of the first and second switching means, the number of switching means, and the connection between the switching means may be any.

Next, an adjustment method for writing temperature compensation data in the piezoelectric oscillator of the present invention will be described.
Note that the adjustment method is exactly the same in both the first and second embodiments, and therefore, the first embodiment will be described here.
First, a piezoelectric oscillator is housed in a thermostat, a measuring device such as a network analyzer is connected to the power supply terminal 14 and the frequency control terminal 15, and a measuring device such as a spectrum analyzer is connected to the output terminal 17. Therefore, the Lo voltage of the CMOS interface is input to the adjustment terminal 19 or the ground state is set, and the piezoelectric oscillator is set in the “vibrator mode”. Next, the temperature in the thermostat is changed, and the frequency temperature characteristic data of the crystal unit 21 alone is acquired by the measuring device such as the network analyzer. Next, temperature compensation data is created from the frequency temperature characteristic data of the crystal unit 21 alone.

Next, the Hi voltage of the CMOS interface is input to the adjustment terminal 19 or is opened, and the piezoelectric oscillator is set to the “oscillator mode”. Therefore, the temperature compensation data is input to the writing terminal 18 and written and stored in the storage means 23. Next, the temperature in the thermostatic chamber is changed, and the frequency temperature characteristic of the oscillation signal output to the output terminal 17 is confirmed with a measuring device such as the spectrum analyzer, thereby completing the adjustment. Since the write terminal 19 often uses a three-wire serial interface, it has a plurality of terminals such as an SCLK (serial clock input) terminal, a DIO (data input / output) terminal, and a CS (chip select) terminal. Is normal.
Therefore, the selection signal may be created inside the IC 26 by a combination of signals inputted to these terminals, and this may be given to the first and second switching means. In this way, the adjustment terminal can be shared by a plurality of write terminals, which is an effective means for further miniaturization.

As described above, the piezoelectric oscillator according to the present invention is housed in a thermostatic chamber in a state where the assembly is completed, and the process from acquisition of the characteristics of the crystal unit alone to writing of temperature compensation data is performed by one measurement facility. This eliminates the need for housing the crystal unit alone in a thermostatic chamber, thus greatly improving production efficiency. In addition, the crystal resonator 21 can be easily separated from the oscillation circuit 22 by grounding the adjustment terminal 19 and there is no need to provide a dedicated measurement terminal on the package, so that failure diagnosis can be easily performed and the size can be reduced. It provides a tremendous effect in providing a simple piezoelectric oscillator.

1 is a block diagram showing a first embodiment of a piezoelectric oscillator according to the present invention. 1 is a block diagram showing a first embodiment of a piezoelectric oscillator according to the present invention. The block diagram which shows the 2nd Example of the piezoelectric oscillator which concerns on this invention. The block diagram which shows the 2nd Example of the piezoelectric oscillator which concerns on this invention. The block diagram of the conventional crystal oscillator.

Explanation of symbols

1, 2... Oscillation circuits 2, 11, 21... Crystal oscillators 3 and 14... Power supply terminals 4 and 16 .. Ground terminals 5 and 17. Crystal oscillation module 10 .. Analog switch 12. Printed circuit board 15. Frequency control terminal 18. Write terminal 19. Adjustment terminal 20 Package 23 Storage means 24a, 24b First switching means 25a 25b, second switching means 26, IC

Claims (7)

  A package including a piezoelectric vibrator, an oscillation circuit, an input / output terminal for inputting or outputting a signal, and an adjustment terminal, and housing the piezoelectric vibrator and the oscillation circuit; and A piezoelectric oscillator comprising a first switching means inserted between and a second switching means inserted between the piezoelectric vibrator and the input / output terminal, wherein the first switching means The connection between the piezoelectric vibrator and the oscillation circuit is set to either a disconnected state or a conductive state based on a selection signal input to the adjustment terminal, and the second switching means includes the selection signal. The piezoelectric oscillator is characterized in that the connection between the piezoelectric vibrator and the input / output terminal is set to either a conductive state or a disconnected state. The second switching means is inserted between the first switching means and the input / output terminal, and based on the selection signal, the piezoelectric vibrator and the input are connected via the first switching means. 2. The piezoelectric oscillator according to claim 1, wherein the connection with the output terminal is set to either a conductive state or a disconnected state.   3. The piezoelectric oscillator according to claim 1, wherein the input / output terminal is any one of a power supply terminal, a ground terminal, a frequency control terminal, and an oscillation signal output terminal.   4. The oscillating circuit, the piezoelectric vibrator, the first switching unit, and the second switching unit are integrated in an IC chip. The piezoelectric oscillator as described.   The oscillation circuit includes storage means for storing temperature compensation data, and a temperature compensation circuit that performs temperature compensation based on the temperature compensation data stored in the storage means. The piezoelectric oscillator according to claim 2, claim 3, or claim 4.   6. The piezoelectric oscillator according to claim 5, wherein the package includes a write terminal for inputting the temperature compensation data from the outside and writing the data into the storage means. An adjustment step of storing the piezoelectric vibrator in a thermostatic chamber; an adjustment step of inputting a selection signal to the adjustment terminal to turn off the first switching means and to turn on the second switching means; From the adjustment step of connecting the measuring device to the input / output terminal and changing the temperature in the thermostatic chamber to acquire the frequency temperature characteristic data of the piezoelectric vibrator alone, and from the acquired frequency temperature characteristic data of the piezoelectric vibrator alone 7. The piezoelectric oscillator according to claim 6, further comprising: an adjustment step of creating temperature compensation data; and an adjustment step of inputting the temperature compensation data to the write terminal and writing the data to the storage means. how to.

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