JPH10290157A - Method and device for compensating temperature for crystal oscillation circuit - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide the method and device for compensating a temperature where component and manufacture management to match ranking of the temperature characteristic of a crystal oscillator is not required and temperature is surely compensated. SOLUTION: A rank discrimination terminal used to discriminate a temperature characteristic ranking of a crystal oscillator 101 is provided to a mount chip of the crystal oscillator 101. When the chip is mounted, a rank discrimination section 205 discriminates ranking of the crystal oscillator 101 through the rank discrimination terminal and a temperature discrimination section 203 discriminates the temperature based on a sensing signal from a temperature sensor 201. An arithmetic/control section 204 retrieves the temperature characteristic in a temperature characteristic memory 206 based on the discrimination ranking and the discrimination temperature and a control signal corresponding to a correction based on the discrimination temperature of the discrimination ranking is fed to a varactor element VC1 through a D/A converter circuit 209 to adjust the capacitance and to control the oscillated frequency.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an automatic frequency control circuit for stabilizing the oscillation frequency of an oscillation circuit using a crystal oscillator, and more particularly, to an automatic frequency control circuit which recognizes the temperature characteristics of each crystal oscillator and The present invention relates to an improvement in a temperature compensation method and device for reliably performing temperature compensation of an oscillation circuit by controlling a frequency.

[0002]

2. Description of the Related Art As a typical oscillator used in a radio device, a crystal oscillator using a crystal oscillator as an oscillation source is known. In general, a crystal oscillator has a variation as shown in FIG. 6, for example, in temperature-oscillation frequency characteristics due to the accuracy of cutting of a crystal oscillator. Needless to say, such variations in the temperature characteristics of the crystal oscillators X1 and X2 hinder stabilization of the frequency of the oscillation circuit including the crystal oscillators X1 and X2.

Therefore, as the most general method for stabilizing the oscillation frequency of a crystal oscillator, a method for improving the characteristics of a single crystal resonator as a single product can be considered. However, according to this method, it is costly to increase the cutting accuracy of the crystal unit, and the production cost is inevitably increased to improve the characteristics as desired. Therefore, as a more realistic method, there has been a method of stabilizing the oscillation frequency of the crystal oscillator based on the temperature characteristics of the crystal oscillation circuit in which the crystal oscillator is mounted.

FIG. 7 shows a circuit configuration of a conventional crystal oscillation circuit to which this method is applied. In this circuit, after the initial adjustment of the oscillation frequency is performed by changing the capacitance of the variable capacitance element C2, the transistor Tr, the capacitor C3,
The oscillation circuit constants and the temperature characteristics are determined so that the temperature characteristics of the crystal oscillator 101 are canceled by components such as C4 and C1.

In this crystal oscillation circuit, a capacitor C
The temperature characteristics of each component such as 2, C3, C4, C1, etc.
In principle, the temperature characteristics should be adjusted to 01. If a component that does not match the temperature characteristics of the crystal oscillator 101 is mounted by mistake, the crystal oscillator 10
If the temperature test is not performed, the temperature characteristics cannot be understood. Moreover, the characteristics of the once mounted chip component were not known at all.

In other words, in this circuit, accurate temperature compensation cannot be expected unless suitable components are mounted in accordance with the temperature characteristics of the crystal oscillator 101. This means that rank matching between the crystal oscillator 101 and other circuit components is indispensable, and for this rank matching, it is necessary to provide each circuit component with a rank identification unit for collating with the rank of the crystal oscillator 101. Means that. As a result, in this type of conventional circuit, component management and manufacturing management are extremely complicated.

[0007] In addition, as an example of frequency control of a crystal oscillator, there has been known a device that performs temperature compensation using a thermistor, a posistor, or the like, such as a TCXO (temperature controlled crystal oscillator). However, this type of conventional device does not have a function of determining the temperature characteristics of the crystal oscillator and controlling the frequency for each temperature characteristic.

[0008]

As described above, as a conventional automatic frequency control method for a crystal oscillator, there are the following methods.
The circuit constant is determined so as to cancel out the variation in the temperature characteristics of the crystal oscillator.

[0010] Like TCXO, temperature compensation is performed using the temperature characteristics of a temperature sensor or a circuit.

In the former method, the necessity of managing the temperature characteristics of circuit components in accordance with the variation in the temperature characteristics of the crystal oscillator complicates parts management and manufacturing control, and the latter method requires the latter method. The method (1) has a problem that the manufacturing method and the process become complicated due to the variation in the temperature characteristics of the crystal oscillator.

The present invention eliminates the above-mentioned problems, simplifies component management and manufacturing control by eliminating the need to rank the temperature characteristics of the crystal oscillator and other circuit components, and reduces variation in the temperature characteristics of the crystal oscillator. It is an object of the present invention to provide a method and an apparatus for compensating temperature of a crystal oscillation circuit which can surely perform temperature compensation.

[0012]

In order to achieve the above object, according to a first aspect of the present invention, a chip having a crystal resonator mounted thereon is provided with a rank determination terminal indicating a temperature characteristic rank of the crystal resonator. In a state where the chip is mounted on the crystal oscillation circuit, a temperature characteristic rank of the crystal resonator in the chip is determined through the rank determination terminal, and an oscillation frequency of the crystal oscillation circuit is determined according to the determined temperature characteristic rank. It is characterized by controlling.

According to a second aspect of the present invention, in the first aspect of the present invention, the relationship between the correction control amount and the temperature is stored in advance as the temperature characteristic for each of the temperature characteristic ranks, and the temperature is stored together with the temperature characteristic rank. Determination, a correction control amount corresponding to the determined rank and temperature is searched from the temperature characteristic, and the oscillation frequency is adjusted by adjusting the capacity of the variable capacitance element in the crystal oscillation circuit based on the correction control amount. It is characterized by controlling.

According to a third aspect of the present invention, in the first aspect of the present invention, the rank determination terminal is connected to the GND of the chip.
The semiconductor device is characterized by comprising a plurality of terminals connected to the terminals, wherein a connection pattern between each of the terminals and the GND terminal is associated with a temperature characteristic rank of a crystal unit in the chip.

According to a fourth aspect of the present invention, in the third aspect of the present invention, a plurality of facing terminals respectively contacting the rank determining terminals when the chip is mounted are provided, and the rank determining terminals are connected through the facing terminals. The temperature characteristic rank is determined by recognizing a pattern.

According to a fifth aspect of the present invention, a crystal resonator is mounted, a crystal resonator chip having a rank determination terminal indicating a temperature characteristic rank of the mounted crystal resonator, and the chip is mounted on a crystal oscillation circuit. In the state, the rank determining means for determining the temperature characteristic rank of the crystal unit in the chip through the rank determining terminal, and controlling the oscillation frequency of the crystal oscillation circuit according to the temperature characteristic rank determined by the rank determining means. And control means for performing the control.

According to a sixth aspect of the present invention, in the fifth aspect of the present invention, a temperature determining means for determining a temperature, and a temperature characteristic indicating a relationship of a correction control amount with respect to the temperature are stored for each of the temperature characteristic ranks. Storage means, comprising a variable capacitance element for adjusting the oscillation frequency of the crystal oscillation circuit,
The control unit searches a correction control amount corresponding to the rank and the temperature determined by the rank determination unit and the temperature determination unit from the temperature characteristics, and adjusts the capacity of the variable capacitance element based on the correction control amount. The oscillation frequency is thereby controlled.

According to a seventh aspect of the present invention, in the fifth aspect of the invention, the rank determination terminal is connected to the GND of the chip.
The semiconductor device is characterized by comprising a plurality of terminals connected to the terminals, wherein a connection pattern between each of the terminals and the GND terminal is associated with a temperature characteristic rank of a crystal unit in the chip.

According to an eighth aspect of the present invention, in the invention of the seventh aspect, a plurality of facing terminals respectively contacting the rank determining terminals when mounting the chip, and connecting the rank determining terminals through the facing terminals. The temperature characteristic rank is determined by recognizing a pattern.

[0020]

Embodiments of the present invention will be described below in detail with reference to the accompanying drawings. FIG. 1 is a circuit diagram showing an embodiment of an automatic frequency control circuit according to the present invention. A crystal oscillation circuit section 10 and a temperature compensation circuit section 20 for performing temperature compensation of the oscillation frequency of the crystal oscillation circuit section 10 are shown.
It consists of.

The crystal oscillation circuit section 10 includes a crystal oscillator 101 using a crystal oscillator and variable capacitance elements VC1 and VC2 for adjusting the oscillation frequency of the crystal oscillator 101, as shown in FIG. It comprises a circuit element. On the other hand, the temperature compensation circuit 20
1. A / D conversion circuit (A / D) 202, temperature determination unit 20
3, arithmetic / control unit 204, rank determination unit 205, temperature characteristic memory 206, memory 207, D / A conversion circuit (D / A
A) It comprises 208 and 209.

In this automatic frequency control circuit, a crystal oscillator 101 mounted on a crystal oscillation circuit section 10 is formed by mounting a crystal oscillator on a chip component as shown in FIG. Based on a configuration in which a connection terminal for a crystal oscillator is formed at a position, and at another position on the chip, a crystal oscillator in the crystal oscillator 101 as shown in FIGS. Are provided with rank determination terminals 101a, 101b, and 101c for determining the temperature characteristic rank.

The rank determining terminals 101a, 101b,
101c is associated with the temperature characteristic rank of the crystal resonator mounted in the chip as described below. For example, the crystal oscillator 101 is used to improve the cutting accuracy of the crystal resonator mounted therein and the like.
In general, a variation in temperature characteristics as shown in FIG. 3A occurs for each of (X1 to Xn). In the present invention, the temperature characteristics of each of the crystal oscillators 101 are classified into A, B,... As shown in FIG. , 101b, and 101c are subjected to processing corresponding to the temperature characteristic rank of each crystal oscillator 101. Specifically, as shown in FIGS. 2B and 2C, the three rank determination terminals 101a, 101b, 1
01c forms a pattern line connected to the GND terminal on the chip, and cuts the pattern line with a pattern matching the temperature characteristic rank of the chip (crystal oscillator 101).

On the other hand, the rank determination unit 205
As shown in the figure, when the crystal oscillator 101 is mounted, the rank determination terminals 101a, 101b, 10
1c, three terminals 2051a, 205
1b, 2051c and these terminals 2051a, 205
Gate circuit 20 connected to each of 1b and 2051c
52a, 2052b, and 2052c.

In the rank determining section 205 having such a configuration, when the crystal oscillator 101 is mounted, the terminals 2051a, 2051
Rank determination terminal 101 that comes into contact with 051b and 2051c
When a, 101b, and 101c are connected to the GND terminal, these terminals 2051a, 2051b,
Gate circuits 2052a and 2052 corresponding to 2051c
b, 2052c to generate an output corresponding to the level “0”, and to output the terminals 2051a, 2051b, 2051c.
Determination terminals 101a, 101b, 101 that come into contact with
When c is cut off from the GND terminal, an output corresponding to level "1" is generated from the gate circuits 2052a, 2052b, 2052c corresponding to these terminals 2051a, 2051b, 2051c.

As a result, the rank determination unit 205, for example, shows (0, 0, 0) shown in FIG. 4A through the rank determination terminals 101a, 101b, and 101c on the crystal oscillator 101 mounted on the crystal oscillation circuit unit 10. Alternatively, a 3-bit output such as (1, 0, 0) shown in FIG. 2B can be obtained, and the arithmetic / control unit 204 determines the temperature characteristic rank of the crystal oscillator 101 being mounted based on the output. can do.

As described above, according to the present invention, by providing the crystal oscillator 101 having the configuration shown in FIG. 2 and the rank determination section 205 having the configuration shown in FIG. 4, the rank determination terminals 101a, 101b, and 101c on the crystal oscillator 101 are provided. About GN
According to the connection pattern with the D terminal, recognition of the temperature characteristic rank of three bits is realized.

Also, in the automatic frequency control circuit of the present invention,
In relation to the temperature characteristic rank of the crystal oscillator 101, the relationship between the correction control amount and the temperature is stored in the temperature characteristic memory 206 as temperature characteristic data for each temperature characteristic rank. This temperature characteristic data is, for example, a temperature characteristic rank A
In the case of, the crystal oscillator 1
This is data defining the temperature versus the correction control amount for each temperature characteristic rank of No. 01.

The arithmetic / control unit 204 is provided with the rank judging unit 20
The temperature characteristic data stored in the temperature characteristic memory 206 is searched based on the rank determination output obtained from No. 5 and the temperature determined by the temperature determining unit 203. For example, when the determination rank is A and the determination temperature is n ° C. By calculating data corresponding to the correction amount α necessary for stabilizing the frequency at this time, and applying the calculated data to the variable capacitance element VC1 through the D / A conversion circuit (D / A) 208, The capacity of the VC1 is variably controlled so as to cancel the quantity α.

Hereinafter, the operation of the automatic frequency control circuit in FIG. 1 will be described in more detail. In this circuit,
An ambient temperature is detected by a temperature sensor 201, and the detection signal is converted from an analog signal to a digital signal by an A / D conversion circuit (A / D) 202 and input to a temperature determination unit 203. The temperature determining unit 203 determines the temperature at this time from the detection signal of the temperature sensor 201, and calculates / determines the determined temperature.
Notify the control unit 204.

The temperature judgment by the temperature judgment section 203 can be made, for example, from the characteristic template of the temperature sensor 201, the ΔV / ΔT value of the detection signal of the temperature sensor 201, and the initial value at the reference temperature. For example, the memory 20
7, the temperature determination can be performed by holding the ΔV / ΔT value of the temperature sensor 201 and storing an initial value (for example, a sensor value at 25 ° C.).

On the other hand, the rank determining section 205 includes rank determining terminals 101a and 101a on the chip on which the crystal oscillator 101 is mounted.
Through 1b and 101c, the temperature characteristic rank of the crystal oscillator 101 is determined by the method described above, and the result of the rank determination is notified to the arithmetic / control unit 204.

After the rank is determined and the temperature is determined, the arithmetic / control unit 204 generates control voltage data for initial adjustment corresponding to the determined temperature, and outputs the control voltage data to a D / A conversion circuit (D / A). ) By giving to the variable capacitance element VC2 through 209, the initial adjustment of the oscillation frequency corresponding to the determination temperature is performed.

Next, the arithmetic / control section 204 specifies the temperature characteristic corresponding to the above-mentioned judgment rank from the temperature characteristic memory 206, reads out the correction amount corresponding to the above-mentioned judgment temperature in this temperature characteristic, and reads out the correction amount. The voltage value data necessary for the frequency correction control of the crystal oscillation circuit corresponding to the amount is calculated.
Then, this data is converted to a D / A conversion circuit (D / A) 208.
To control the oscillation frequency by variably adjusting the capacitance by converting it into an analog signal and supplying it to the variable capacitance element VC1. By this control, the frequency fluctuation according to the temperature characteristic of the crystal oscillator 101 mounted at this time is canceled, and the oscillation frequency is stabilized.

FIG. 5 is a circuit diagram showing a modification of the automatic frequency control circuit in FIG. In this variation, D
The circuit configuration is the same as that shown in FIG. 1 except for a portion including a / A conversion circuit (D / A) 301 and a GCA (gain control amplifier) 302. Therefore, also in this modification, in a state where the crystal oscillator 101 is mounted on the crystal oscillation circuit section 10, the rank determination terminals 101a, 101b, 10
1c, the temperature characteristic rank of the crystal oscillator 101 is determined, and the oscillation frequency can be controlled by adjusting the capacitance of the variable capacitance element VC1 according to the determined temperature characteristic rank.

Further, in this modified example, the output control of a radio device equipped with this automatic frequency control circuit is implemented by a portion comprising a D / A conversion circuit (D / A) 301 and a GCA (gain control amplifier) 302. I do. That is,
In this modified example, after the temperature is determined by the temperature determination unit 203 based on the detection signal of the temperature sensor 201, the calculation / control unit 20
4 provides a control signal via a D / A conversion circuit (D / A) 301 and changes the gain (VG) of the GCA 302 to control the transmission output at the J terminal. Some of today's various wireless devices have a transmission output control function having such a configuration. Therefore, in this type of radio, a crystal oscillator (chip) using an existing facility related to the transmission output control function and additionally having a rank determination terminal is provided.
101, the rank determination unit 205 and the temperature characteristic memory 20
The temperature compensation function according to the present invention can be realized extremely inexpensively by adding only a few circuits such as 6.

In the above-described embodiment, only the crystal oscillator is assumed as the object of the rank determination. However, the peripheral components other than the crystal oscillator can be ranked, and the rank of the determined component can be determined. The configuration may be such that the oscillation frequency is controlled accordingly.

[0038]

As described above, according to the present invention,
A rank determination terminal indicating a temperature characteristic rank of the crystal resonator is provided on a chip on which the crystal resonator is mounted, and the temperature characteristic rank of the crystal resonator is determined through the rank determination terminal while the chip is mounted on an oscillation circuit. Since the oscillation frequency is controlled by adjusting the capacitance of the variable capacitance element according to the determined temperature characteristic rank, it is not necessary to match the type of the special temperature correction capacitor and the rank of the crystal resonator. In addition, the rank of the crystal unit can be identified in a mounted state. As a result, the present invention has an excellent advantage that component management for temperature compensation is substantially unnecessary, components are easily manufactured, and temperature compensation can be reliably performed with an inexpensive configuration.

[Brief description of the drawings]

FIG. 1 is a circuit diagram showing an embodiment of an automatic frequency control circuit according to the present invention.

FIG. 2 is a diagram showing an external structure of a crystal resonator mounting chip used in the present invention.

FIG. 3 is a view for explaining temperature characteristics of a quartz oscillator used in the present invention and its ranking.

FIG. 4 is a circuit diagram of a rank determination unit of the automatic frequency control circuit according to the present invention.

FIG. 5 is a circuit diagram showing a modification of the automatic frequency control circuit according to the present invention.

FIG. 6 is a view for explaining variation in frequency versus temperature characteristics in a crystal resonator.

FIG. 7 is a circuit diagram showing a configuration of an oscillation frequency control function in a conventional crystal oscillation circuit.

[Explanation of symbols]

 Reference Signs List 10 crystal oscillation circuit section 101 crystal oscillator 101a, 101b, 101c rank determination terminal 20 temperature compensation circuit section 201 temperature sensor 202 A / D conversion circuit (A / D) 203 temperature determination section 204 calculation / control section 205 rank determination section 2051a, 2051b, 2051c Terminals 2052a, 2052b, 2052c Gate circuit 206 Temperature characteristic memory 207 Memory 208, 209, 301 D / A conversion circuit (D / A) 302 GCA (gain control amplifier)

Claims (8)

[Claims] 1. A chip having a crystal resonator mounted thereon is provided with a rank determination terminal indicating a temperature characteristic rank of the crystal resonator, and the chip mounted on a crystal oscillation circuit is connected to the chip through the rank determination terminal. A temperature compensation method for a crystal oscillation circuit, comprising: judging a temperature characteristic rank of a crystal resonator in the device; and controlling an oscillation frequency of the crystal oscillation circuit according to the determined temperature characteristic rank. 2. A relationship between a temperature and a correction control amount is stored in advance as a temperature characteristic for each temperature characteristic rank, a temperature is determined together with the temperature characteristic rank, and a correction control corresponding to the determined rank and temperature is performed. 2. The crystal oscillation circuit according to claim 1, wherein the oscillation frequency is controlled by retrieving an amount from the temperature characteristic and adjusting the capacitance of a variable capacitance element in the crystal oscillation circuit based on the correction control amount. Temperature compensation method. 3. The rank determination terminal is connected to the GND of the chip.
The terminal according to claim 1, comprising a plurality of terminals connected to the terminal, wherein a connection pattern between each terminal and the GND terminal is associated with a temperature characteristic rank of a crystal unit in the chip. Temperature compensation method for crystal oscillation circuit. 4. A temperature characteristic rank is determined by providing a plurality of facing terminals respectively contacting the rank determining terminals when mounting the chip, and recognizing a connection pattern of the rank determining terminals through the facing terminals. 4. The temperature compensation method for a crystal oscillation circuit according to claim 3, wherein: 5. A crystal resonator chip having a crystal resonator mounted thereon and having a rank determination terminal indicating a temperature characteristic rank of the mounted crystal resonator, and the chip mounted on a crystal oscillation circuit. Rank determining means for determining a temperature characteristic rank of the crystal unit in the chip through a determination terminal; andcontrol means for controlling an oscillation frequency of the crystal oscillation circuit according to the temperature characteristic rank determined by the rank determining means. A temperature compensation device for a crystal oscillation circuit, comprising: 6. A temperature determining means for determining a temperature, a temperature characteristic storing means for storing a temperature characteristic indicating a relationship between a temperature and a correction control amount for each temperature characteristic rank, and a variable for adjusting an oscillation frequency of the crystal oscillation circuit. A capacitive element,
The control unit searches a correction control amount corresponding to the rank and the temperature determined by the rank determination unit and the temperature determination unit from the temperature characteristics, and adjusts the capacity of the variable capacitance element based on the correction control amount. 6. The temperature compensation device for a crystal oscillation circuit according to claim 5, wherein the oscillation frequency is controlled by controlling the oscillation frequency. 7. The rank determination terminal is connected to the GND of the chip.
The terminal according to claim 5, comprising a plurality of terminals connected to the terminals, wherein a connection pattern between each of the terminals and the GND terminal is associated with a temperature characteristic rank of a crystal unit in the chip. Temperature compensation device for crystal oscillation circuit. 8. A method for determining the temperature characteristic rank by providing a plurality of facing terminals respectively contacting the rank determining terminals when mounting the chip, and recognizing a connection pattern of the rank determining terminals through the facing terminals. The temperature compensation device for a crystal oscillation circuit according to claim 7, wherein: