JP2003258551A - Temperature compensation circuit for oscillation circuit and temperature compensation method thereof - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a temperature compensation circuit for an oscillation circuit capable of realizing a temperature compensation operation with high accuracy in following to a change in an operating environment temperature while maintaining low power consumption. <P>SOLUTION: A correction interval decision circuit 12 obtains a change in temperature on the basis of a detection temperature from a temperature sensor 16 and decides a correction interval for correcting an oscillation frequency of an oscillation circuit 7 in response to the change in temperature. A selection circuit 14 selects a clock signal with a frequency corresponding to the correction interval and gives the selected clock signal to a compensation operation control circuit 15. A temperature-digital signal conversion circuit 17 converts a temperature sensed by the temperature sensor 16 into digital temperature data. A correction value decision circuit 18 reads a correction value corresponding to the temperature data and sets the correction value to a correction value register 19. Switches S1 to Sn of the oscillation circuit 7 are switched on/off depending on storage contents of the correction value register 6 to change the capacitance of capacitors C1 to Cn. <P>COPYRIGHT: (C)2003,JPO

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention is applied to an oscillation circuit or the like which is incorporated in an electronic device and operates by a backup power supply even when the main power supply of the electronic device is cut off. The present invention relates to a temperature compensating circuit for an oscillating circuit, which detects the temperature and compensates the temperature of the oscillating circuit based on the detected temperature, and a temperature compensating method thereof.

[0002]

2. Description of the Related Art Conventionally, an example shown in FIG. 9 is known as an example of a temperature compensation circuit of this type of oscillation circuit. As shown in FIG. 9, the temperature compensation circuit 1 includes a compensation operation control circuit 2, a temperature sensor 3, a temperature-digital signal conversion circuit 4,
It is composed of a correction value determination circuit 5 and a correction value register 6.

The oscillation circuit 7 to be temperature-compensated in the temperature compensation circuit 1 is, for example, an inverter type oscillation circuit. That is, as shown in FIG. 9, the oscillator circuit 7 includes an inverter 8, a crystal unit 9, resistors R1 and R2, a plurality of electronic switches S1 to Sn, and switches S1 to Sn.
It is composed of a plurality of capacitors C1 to Cn connected in series with Sn. Then, by turning on / off the switches S1 to Sn, the capacities of the capacitors C1 to Cn are changed to adjust the oscillation frequency.

Next, the operation of the temperature compensating circuit 1 having such a configuration will be described with reference to FIGS. 9 and 10. The compensating operation control circuit 2 receives, for example, 0.1 from the outside.
A clock signal of [Hz] is input, and each operation of the temperature sensor 3, the temperature-digital signal conversion circuit 4, the correction value determination circuit 5, and the correction value register 6 is performed based on the clock signal. It is designed to be controlled.

That is, the compensation operation control circuit 2 outputs a trigger signal to the temperature-digital signal conversion circuit 4 at the timing when the clock signal is input, and the temperature-digital signal conversion circuit 4 detects the temperature detected by the temperature sensor 3. Is controlled so as to be converted into temperature data composed of a digital signal. The temperature data is output to the correction value determination circuit 5. next,
Since the compensation operation control circuit 2 puts the correction value determination circuit 5 into the operating state, the correction value determination circuit 5 fetches the temperature data.

The correction value determination circuit 5 reads out the correction value corresponding to the temperature data from the correction data table stored in advance in the memory based on the temperature data taken in, and the read correction value is stored in the correction value register 6. Output, and then the operation is stopped. As a result, the correction value is set in the correction value register 6, and the switches S1 to Sn of the oscillation circuit 7 are controlled to be turned on / off in accordance with the content of the correction value to select (set) the capacitors C1 to Cn. As a result, the oscillation frequency of the oscillation circuit 7 is adjusted (controlled).
To be done.

The temperature compensating operation of the oscillation circuit 7 by the temperature compensating circuit 1 as described above is carried out at every timing when a clock signal is inputted to the compensating operation control circuit 2, as shown in FIG. It is performed once or so intermittently.

[0008]

By the way, the low-frequency oscillation circuit may be used as a clock function circuit (timer circuit) incorporated in an electronic device or as an oscillation source of the clock function circuit. . In this case, operation with a backup power source such as a battery is required when the main power source is off. When operating the backup power supply, low power consumption operation is required.

On the other hand, the oscillator circuit is required to have a high accuracy of the oscillation frequency. In this case, the temperature compensating circuit intermittently performs the temperature compensating operation as described above to reduce the power consumption of the temperature compensating circuit. Is effective. However, in the conventional temperature compensating circuit of the oscillation circuit, the temperature compensating operation is intermittently performed.
The operation interval is relatively long, about once every 0 seconds. Moreover, as shown in FIG. 10, the operation interval is fixed regardless of the magnitude of the temperature change.

For this reason, when the oscillation circuit having the temperature compensation circuit is used by being incorporated in an electronic device such as a computer, the temperature in the housing immediately after the main power of the electronic device is turned on. Rapid changes (eg, within a few minutes,
Fluctuation of several tens of degrees Celsius). As a result, the conventional temperature compensating operation by the temperature compensating circuit has a disadvantage that it cannot follow such a rapid change in environmental temperature.

Further, in the temperature compensating circuit of the oscillator circuit, in the case of the operation by the backup power source as described above, it is desired to prioritize low power consumption. On the other hand, in the case of the operation by the main power source, it is also desired to use the temperature compensation operation with higher accuracy. Therefore, it is also desirable to use such that one of both uses can be selected as needed.

Therefore, in view of the above points, an object of the present invention is to provide a temperature compensating circuit for an oscillator circuit, which can realize a highly accurate temperature compensating operation by following a change in operating environment temperature while maintaining low power consumption. And to provide a temperature compensation method therefor. Another object of the present invention is to use the temperature compensation circuit of the oscillation circuit and the temperature compensation circuit of the oscillation circuit which can be used according to need, which enables use in which low power consumption is prioritized or precision in temperature compensation operation is prioritized. To provide a method.

[0013]

In order to solve the above problems and achieve the object of the present invention, the inventions described in claims 1 to 8 are configured as follows. That is, claim 1
The invention described in (1) is a temperature compensation circuit of an oscillation circuit, which detects the ambient temperature of the oscillation circuit with a temperature sensor and performs temperature compensation of the oscillation circuit based on the detected temperature. A correction interval determining means for determining a temperature change over time, and determining a predetermined correction interval for correcting the oscillation frequency of the oscillation circuit according to the calculated temperature change, and a correction determined by the correction interval determining means. An oscillation frequency control unit that takes in the temperature detected by the temperature sensor at each interval and adjusts the oscillation frequency of the oscillation circuit according to the detected temperature is provided.

According to a second aspect of the present invention, in the temperature compensating circuit for the oscillation circuit according to the first aspect, the correction interval determining means determines the correction interval when the calculated temperature change exceeds a set value. The correction interval is determined to be small, and the correction interval is determined to be larger when the temperature change is less than the set value. According to a third aspect of the present invention, in the temperature compensating circuit for the oscillator circuit according to the first or second aspect, the correction interval determining means is
A signal generated when the main power of the oscillation circuit is turned on is received, and a predetermined correction interval is determined when the signal is received. It is a thing. According to a fourth aspect of the invention, in the temperature compensation circuit of the oscillation circuit according to the third aspect,
The signal received by the correction interval determining means is a signal from a main power supply voltage detection circuit that monitors turning on or off of the main power supply. According to a fifth aspect of the present invention, in the temperature compensation circuit of the oscillation circuit according to any one of the first to third aspects, the correction interval determination means has a consumption current priority mode in which reduction of consumption current is prioritized.
The correction priority mode in which the accuracy of the oscillation frequency of the oscillation circuit is prioritized is set from the outside.

According to a sixth aspect of the present invention, in the temperature compensating circuit for the oscillation circuit according to the fifth aspect, the correction interval determining means determines the calculated temperature when the current consumption priority mode is set. The change is compared with a first allowable range, the correction interval currently determined is maintained if the temperature change is within the first allowable range, and the temperature change exceeds the first allowable range. The correction interval currently determined is decreased, and the correction interval currently determined is increased when the temperature change falls below the first allowable range, and the correction priority mode is set. In the case where the temperature change is determined, the obtained temperature change is compared with a second allowable range, and if the temperature change is within the second allowable range, the currently determined correction interval is maintained, and the temperature change is Above the second tolerance If the temperature change is below the second allowable range, the correction interval currently determined is reduced to a predetermined correction interval according to the degree of exceeding the currently determined correction interval. It is characterized by being made larger.

According to a seventh aspect of the present invention, there is provided a temperature compensating method for an oscillation circuit, wherein an ambient temperature of the oscillation circuit is detected by a temperature sensor, and the temperature of the oscillation circuit is compensated based on the detected temperature. The temporal temperature change of the temperature detected by the sensor is obtained, and a predetermined correction interval for correcting the oscillation frequency of the oscillation circuit is determined according to the obtained temperature change,
The temperature detected by the temperature sensor is fetched at each of the determined correction intervals, and the oscillation frequency of the oscillation circuit is adjusted according to the detected temperature.

According to an eighth aspect of the present invention, in the temperature compensation method for an oscillation circuit according to the seventh aspect, the correction interval is
It is characterized in that it is decided to be small when the obtained temperature change exceeds a set value, and is decided to be large when the temperature change is below the set value. According to the present invention having such a configuration, it is possible to realize a highly accurate temperature compensation operation that follows changes in the operating environment temperature while maintaining low power consumption.

Further, according to the present invention, it is possible to prioritize low power consumption or prioritize the accuracy of temperature compensation operation, so that it can be used as required.

[0019]

BEST MODE FOR CARRYING OUT THE INVENTION The configuration of an embodiment of the present invention will be described below with reference to FIG. As shown in FIG. 1, the temperature compensation circuit 11 according to this embodiment includes a correction interval determination circuit 12, a correction interval register 13, and a selection circuit 14.
And a compensation operation control circuit 15, a temperature sensor 16, a temperature-digital signal conversion circuit 17, a correction value determination circuit 18, and a correction value register 19.

Here, the correction interval determination circuit 12, the correction interval register 13 and the selection circuit 14 form a correction interval determination means. Further, the correction value determination circuit 18 and the correction value register 19 form an oscillation frequency control means. The temperature compensating circuit 11 detects a temperature change with respect to time around the oscillation circuit 7 and, according to the magnitude of the temperature change (temperature gradient), as shown in FIG. Is made different. That is, when the temperature change is large, the temperature compensation operation interval is shortened to frequently perform temperature compensation, and when the temperature change is small, the temperature compensation operation interval is lengthened.

Here, the oscillation circuit 7 to be temperature-compensated.
Is, for example, an inverter type oscillation circuit, and is similar to the oscillation circuit 7 in FIG. Therefore, the same constituent elements are designated by the same reference numerals and the description thereof will be omitted. Correction interval determination circuit 1
Reference numeral 2 denotes temperature data obtained by converting the temperature detected by the temperature sensor 16 by the temperature-digital signal conversion circuit 17, a main power-on signal or a main power-off signal generated and output by the main power supply voltage detection circuit 23 shown in FIG. Based on the priority control signal indicating the above or the operation mode setting signal output from the timer circuit 21 shown in FIG. 4 which will be described later, the correction interval when the temperature compensation (temperature correction) operation of the oscillation circuit 7 is performed will be described later. It is a circuit to decide. Once the main power-on signal is input, the state is maintained until the main power is turned off. The correction interval register 13 includes a correction interval determination circuit 12
It is a register that stores the data of the correction interval determined in.

The selection circuit 14 determines, for example, 0.1 according to the correction interval data stored in the correction interval register 13.
It is a circuit that selects one of the clock signals of [Hz], 1 [Hz], 4 [Hz], 16 [Hz], or 64 [Hz]. The selected clock signal is supplied to the compensation operation control circuit 15. The compensation operation control circuit 15 is a circuit that controls at least the correction value register 19 based on the clock signal from the selection circuit 14. When the power consumption is reduced, the compensation operation control circuit 15 may control the temperature sensor 16, the temperature-digital signal conversion circuit 17, and the correction value determination circuit 18 in addition to the correction value register 19. In the following, description will be given on the premise of controlling each unit. The temperature sensor 16 is a sensor that detects (measures) the temperature of the environment in which the oscillator circuit 7 is used, and the temperature-digital signal conversion circuit 17 converts an analog signal corresponding to the detected temperature.
To be supplied to.

The temperature-digital signal conversion circuit 17 is a circuit for converting an analog signal corresponding to the detected temperature detected by the temperature sensor 17 into temperature data composed of digital signals. The obtained temperature data is supplied to the correction value determination circuit 18 and the correction interval determination circuit 12, respectively. The correction value determination circuit 18 is a circuit that, when temperature data is captured from the temperature-digital signal conversion circuit 17, determines a correction value based on the captured temperature data. That is, the correction value determination circuit 18 has a correction value table, reads the correction value corresponding to the temperature data by referring to the correction value table, and outputs the read correction value to the correction value register 19. It has become.

The correction value register 19 stores the content of the correction value in the oscillation circuit 7 under the control of the compensation operation control circuit 15.
It is a register that temporarily stores the switches S1 to Sn to turn them on and off. Next, an example of the operation of the embodiment having such a configuration will be described with reference to FIGS.

In the following, the operation after the main power is turned on will be described assuming that the correction interval determination circuit 12 does not receive the operation mode setting signal. First, at the initial stage when the main power is turned on, the correction interval determination circuit 12 determines the correction interval data for performing the temperature compensation operation of the oscillation circuit 7 as an initial value, for example, once a second, and the correction interval data is determined. Is set in the correction interval register 13. As a result, the selection circuit 14 selects 1 [H
z], and the selected clock signal is supplied to the compensation operation control circuit 15. The compensation operation control circuit 15 outputs the trigger signal a as shown in FIG. 3A at the timing when the clock signal is input. Based on this trigger signal a, the temperature-digital signal conversion circuit 17 takes in the temperature detected by the temperature sensor 16 and obtains temperature data T = T1 consisting of a digital signal.

Next, the compensation operation control circuit 15 puts the correction value determination circuit 18 into operation, so that the correction value determination circuit 1
8 fetches the temperature data T1 as shown in FIG. The correction value determination circuit 18 reads a correction value c corresponding to the temperature data T1 from the correction value table based on the fetched temperature data T1, and the read correction value c is supplied to the correction value register 19. (Fig. 3
(See (C)).

The read correction value c is set in the correction value register 19, the on / off control of the switches S1 to Sn of the oscillation circuit 7 is controlled according to the content f of the correction value register 19, and the capacitors C1 to Cn. Is selected. As a result, the oscillation frequency of the oscillation circuit 7 is adjusted. After that, when the second clock signal is input to the compensation operation control circuit 15 and the second trigger signal a is output from the compensation operation control circuit 15 as shown in FIG. -The digital signal conversion circuit 17 obtains temperature data T = T2 based on the temperature detected by the temperature sensor 16. Further, the correction value determination circuit 18 takes in the temperature data T2 as shown in FIG. 3B, reads the correction value c corresponding to the temperature data T2, and the read correction value c is the correction value c. It is output to the register 19 (see FIG. 3C).

Then, as shown in FIG. 3 (E), when the switching timing signal e is output from the compensation operation control circuit 15, the correction value register 19 outputs the correction value c determined by the correction value determination circuit 18. take in. Therefore, the content f of the correction value register 19 is rewritten as shown in FIG.
The switches S1 to Sn of the oscillation circuit 7 are controlled to be turned on and off according to the content f, and the capacitors C1 to Cn are selected.

On the other hand, the temperature data T2 obtained by the temperature-digital signal conversion circuit 17 as described above is supplied to the correction interval determination circuit 12. Therefore, the correction interval determination circuit 12 calculates the temperature change (temperature gradient) R with time from the previous temperature data T1 and the current temperature data T2 by the following equation (1). R = | T2-T1 | / S (1) where S is the measurement interval between the previous temperature data T1 and the current temperature data T2, that is, the correction interval data determined by the correction interval determination circuit 12. (The trigger signal a in FIG.
Interval).

Next, the correction interval determination circuit 12 compares the obtained temperature change R with a preset allowable range. As a result of the comparison, if the temperature change R falls within the allowable range, the correction interval determination circuit 12 maintains the correction interval data without changing the currently determined correction interval data.

On the other hand, when the temperature change R exceeds the allowable range (set value), the correction interval data is made smaller than the current value. Therefore, the correction interval determination circuit 12
For example, the selection circuit 14 determines the correction interval data for selecting the clock signal of 4 [Hz]. The determined correction interval data is obtained when the switching timing signal h is output from the compensation operation control circuit 15 as shown in FIG.
It is taken into the correction interval register 13 at that timing (see FIG. 3 (G)).

On the other hand, when the temperature change R is below the allowable range, the correction interval data is made larger than the current value. Therefore, the correction interval determination circuit 12 determines the correction interval data so that, for example, the selection circuit 14 selects the clock signal of 0.1 [Hz].
Is output to. Hereinafter, the series of operations described above is repeated. Therefore, as shown in FIG. 2B, the temperature compensating circuit 11 intermittently performs the temperature compensating operation of the oscillating circuit 7 at the correction interval determined according to the temperature change.

As described above, in this embodiment,
The temperature change with respect to the time around the oscillation circuit 7 is obtained, and when this temperature change exceeds the allowable range, the temperature correction operation interval of the oscillation circuit is shortened to frequently perform temperature compensation. On the other hand, when the temperature change is small, the correction interval of the temperature compensation operation is increased to perform temperature compensation to the extent that the oscillation frequency of the oscillation circuit can maintain a predetermined accuracy.

Therefore, according to this embodiment, it is possible to realize a highly accurate temperature compensation operation that follows changes in the operating environment temperature of the oscillation circuit while maintaining low power consumption. next,
The oscillation circuit 7 including the temperature compensation circuit 11 according to the embodiment of the present invention is applied to an oscillation source of a timer circuit included in an electronic device (electronic system) such as a computer, and a configuration example of the electronic device in this case is described. 4 will be described with reference to FIG.

In such an electronic device, the timer circuit (clock function circuit) 21 needs to be operating even when the main power supply is turned off. At this time, power is supplied from a backup power supply such as a battery. It is like this. As shown in FIG. 4, the switching of the power source is performed by the power source switching circuit 22 and the voltage detection circuit 23. That is, the power supply switching circuit 22 is normally connected to the backup power supply side, and the timer power supply circuit 22 is driven by the backup power supply. However, when the main power supply voltage detection circuit 23 detects that the main power supply has been turned on, it sends a main power supply turn-on signal to that effect to the power supply switching circuit 22. The power supply switching circuit 22 is adapted to automatically switch the power supply from the backup power supply to the main power supply in response to the main power-on signal.

Further, the main power-on signal of the main power-supply voltage detection circuit 23 is also supplied to the timer circuit 21, and the timer circuit 21 switches from the backup mode to the main power-supply mode based on the main power-on signal and the low voltage is supplied. The current consumption operation mode is switched to the normal mode.
Further, the main power-on signal of the main power supply voltage detection circuit 23 is
Correction interval determination circuit 12 of temperature compensation circuit 11 according to the present invention
Is supplied as a priority control signal of high priority. This is used as the correction interval determination information of the correction interval determination circuit 12 and is preferentially controlled within a certain period of time, as will be described later, when the temperature in the housing rapidly changes immediately after the main power is turned on. This is to allow it. As a result, the temperature compensating circuit 11 can realize a temperature compensating operation that follows a rapid change in temperature.

Further, the timer circuit 21 is the temperature compensation circuit 1
1, a current consumption priority mode that prioritizes reduction of current consumption,
An operation mode setting register 24 is provided that can arbitrarily set either one of the temperature correction priority modes that prioritize the accuracy of the temperature compensation operation of the oscillator circuit 7. Therefore, by presetting the operation mode according to the required accuracy of the device used in the operation mode setting register 24, or by the controller 25 in the electronic device shown in FIG. 4, the main power supply state of the electronic device is set. Of the temperature compensation circuit 11 and the power saving control program, the temperature compensation circuit 11 can change the setting of the operation mode as needed.
The temperature compensation operation can be performed according to the operation mode.

Next, an operation example (determination processing example) of the correction interval determination circuit 12 of the temperature compensation circuit 11 in the electronic device as shown in FIG. 4 will be described with reference to the flowchart of FIG. 6A shows the relationship between the upper limit value R1 and the lower limit value R2, which is the allowable range (first allowable range) in the current consumption priority mode, and FIG. 6B shows the allowable range in the correction priority mode ( It is a figure for demonstrating the relationship between the upper limit R3 and the lower limit R4 which are 2nd allowable range), and a correction | amendment interval. In FIG. 6B, when the temperature change R exceeds the upper limit value R3, or when the main power source is turned on or off, a predetermined correction interval according to the extent of exceeding the currently set correction interval. For example, the description will be made assuming that the shortest value is set.

First, in step S1, the voltage detection circuit 2
Based on the presence / absence of the main power-on signal from 3, it is determined whether or not it is the priority control mode. If the result of this determination is that there is a main power-on signal and it is determined to be the priority control mode, the routine proceeds to step S2. In step S2, the correction interval determination circuit 12 determines the shortest correction interval in order to minimize the correction operation interval of the oscillation circuit 7. The determined correction interval data is stored in the correction interval register 13 so that the selection circuit 14 selects and outputs the clock signal of 64 [Hz]. On the other hand, if it is determined in step S1 that there is no main power-on signal and it is not the priority control, the process proceeds to the next step S3. In step S3, it is determined which of the current consumption priority mode and the correction priority mode is set. If the result of this determination is that the current consumption priority mode has been set, the next step S
Go to 4.

In step S4, it is determined whether or not the temperature change R obtained by the equation (1) as described above exceeds the upper limit value R1 of the allowable value (see FIG. 6A). As a result of the determination, if the temperature change R exceeds the upper limit R1 of the allowable value, the process proceeds to step S5. In step S5, the correction interval determination circuit 12 determines a correction interval that is one step smaller than the current correction interval in order to reduce the correction operation interval of the oscillation circuit 7 by one step. The determined correction interval data is stored in the correction interval register 13, and the selection circuit 14 selects and outputs the clock signal according to the correction interval data.

On the other hand, when the temperature change R is less than or equal to the upper limit value R1 of the allowable value, the process proceeds to the next step S6. Step S6
Then, it is determined whether or not the temperature change R obtained by the equation (1) is not less than the allowable value R2 (see FIG. 6A). As a result of the determination, when the temperature change R is equal to or more than the lower limit value R2 of the allowable value,
Go to step S7. In step S7, the correction interval determination circuit 12 maintains the correction operation interval of the oscillation circuit 7 at the current value. Therefore, in this case, the correction interval register 1
The contents of 3 are not rewritten.

On the other hand, if the temperature change R is less than the lower limit value R2 of the allowable value, the process proceeds to step S8. In step S8, the correction interval determination circuit 12 determines a correction interval that is one step larger than the current correction interval in order to increase the correction operation interval of the oscillation circuit 7 by one step. The determined correction interval data is stored in the correction interval register 13, and the selection circuit 14 selects and outputs the clock signal according to the correction interval data.

On the other hand, when it is determined in step S3 that the correction priority mode is set, step S3 is performed.
Proceed to 9. In step S9, it is determined whether or not the temperature change R obtained by the equation (1) exceeds the upper limit R3 of the allowable value (see FIG. 6 (B)). As a result of the judgment, the temperature change R
When exceeds the upper limit R3 of the allowable value, the process proceeds to step S10. In step S10, the correction interval determination circuit 12 determines the shortest correction interval in order to minimize the correction operation interval of the oscillation circuit 7. The determined correction interval data is stored in the correction interval register 13, whereby the selection circuit 14 selects and outputs the clock signal of 64 [Hz].

On the other hand, if the temperature change R is less than or equal to the upper limit value R3 of the allowable value, the process proceeds to the next step S11. Step S
In 11, it is determined whether or not the temperature change R obtained by the equation (1) is not less than the lower limit value R4 of the allowable value (see FIG. 6 (B)). As a result of the determination, if the temperature change R is not less than the lower limit value R4 of the allowable value, the process proceeds to step S12. In step S12,
The correction interval determination circuit 12 maintains the interval of the correction operation of the oscillation circuit 7 at the current value. Therefore, in this case, the contents of the correction interval register 13 are not rewritten.

On the other hand, when the temperature change R is less than the lower limit value R4 of the allowable value, the process proceeds to step S11. In step S11, the correction interval determination circuit 12 determines a correction interval that is one step larger than the current correction interval in order to increase the correction operation interval of the oscillation circuit 7 by one step. The determined correction interval data is stored in the correction interval register 13,
The selection circuit 14 selects and outputs a clock signal according to the correction interval.

As described above, the temperature compensation circuit 1 shown in FIG.
With No. 1, when the main power is turned on, the interval of the correction operation of the oscillation circuit 7 can be frequently performed with the shortest value. Therefore, when the main power is turned on, the temperature compensation operation is performed according to the temperature change even if the operating environment temperature of the oscillation circuit changes rapidly, and it is possible to prevent the oscillation accuracy of the oscillation circuit 7 from temporarily lowering. Further, in the temperature compensating circuit 11, when the oscillation circuit 7 or the timer circuit 21 is used as a backup power source, if the consumption current priority mode is set as the operation mode, the temperature compensation as in steps S4 to S8 in FIG. You can take action. Therefore, in the consumption current priority mode, it is possible to improve the oscillation accuracy of the oscillator circuit while reducing the consumption current of the backup power supply. Further, in the temperature compensating circuit 11, when the main power supply is used, if the correction priority mode is set as the operation mode, steps S9 to S9 of FIG.
A temperature compensation operation like S13 can be performed. Therefore, in the correction priority mode, the accuracy of the oscillation frequency of the oscillation circuit can be prioritized.

Next, the operation when the main power supply is cut off will be described with reference to FIG. As shown in FIG. 2, when the main power supply is cut off at a certain arbitrary time point, the backup power supply is switched to, and when the correction interval determination circuit 12 shown in FIG. 1 detects the main power supply disconnection signal, it is fixed as an initial value of the correction interval data. During the time, the shortest value is preferentially determined, for example, and this is set in the correction interval register 13. Then, after the main power supply is cut off and the shortest value is set, as shown in FIG. 2, the temperature inside the electronic device decreases and the correction interval by the temperature compensating circuit 11 is set according to the temperature gradient. The temperature compensation operation is performed. Since this compensating operation is the same as the operation when the main power source is turned on, detailed description thereof will be omitted. Note that, in this operation, the consumption current priority mode or the correction priority mode can be selected, as described above. Further, the same effect as that obtained by the operation after the main power is turned on can be obtained. In the above embodiment, the temperature compensation target of the temperature compensation circuit 11 has been described as the oscillation circuit 7 including an inverter type oscillation circuit as shown in FIG.

However, in the temperature compensating circuit 11, instead of the oscillating circuit 7, an oscillating circuit 31 made of a CMOS transistor as shown in FIG. 7 or an oscillating circuit 41 made of a bipolar transistor as shown in FIG. 8 is used. Can be compensated. The oscillator circuit 31 shown in FIG.
It is composed of an S inverter 32, a crystal oscillator 33, variable capacitance diodes 34 and 35, a control terminal 36, and the like. Then, an oscillation control voltage is externally applied to the control terminal 36, whereby the electrostatic capacitances of the variable capacitance diodes 34 and 35 are varied, and the oscillation frequency can be adjusted.

In this case, the temperature compensating circuit 11 operates as shown in FIG.
In addition to the above-mentioned constituent elements, an A / D conversion circuit (not shown) for converting the content stored in the correction value register 19 into an analog voltage is provided, and the output voltage of this A / D conversion circuit is controlled by the control terminal 36 to oscillate. It will be configured to be applied as a voltage. Further, the oscillator circuit 41 shown in FIG. 8 includes a bipolar transistor 42, a crystal oscillator 43, and a variable capacitance diode 4.
4, control terminal 45 and the like. Then, the output voltage from the A / D conversion circuit is applied to the control terminal 45 as a control voltage, thereby varying the capacitance of the variable capacitance diode 44 and adjusting the oscillation frequency. Further, in the oscillation circuit of the above-described embodiment, the case where the crystal oscillator is applied to the present invention as the oscillation source has been described, but the present invention is not limited to this, and the piezoelectric ceramic,
A vibrator made of lithium tantalate or lithium niobate may be used. The same effect can be obtained by using a surface acoustic wave resonator.

[0050]

As described above, according to the present invention,
It is possible to realize a highly accurate temperature compensation operation that follows changes in the operating environment temperature while maintaining low power consumption. Further, according to the present invention, it is possible to prioritize low power consumption or prioritize accuracy of temperature compensation operation.
It is convenient because it can be used as needed.

[Brief description of drawings]

FIG. 1 is a configuration diagram showing a configuration of a temperature compensation circuit according to an embodiment of the present invention together with a configuration of an oscillation circuit.

FIG. 2 is a diagram showing a time course when the temperature compensating circuit according to the embodiment of the present invention intermittently performs the temperature compensating operation according to a temperature change.

FIG. 3 is a timing chart of an example for explaining the operation of each part of the temperature compensation circuit according to the embodiment of the present invention.

FIG. 4 is a block diagram showing an example of the configuration of an electronic device in which an oscillation circuit including a temperature compensation circuit according to an embodiment of the present invention is applied to an oscillation source of a timer circuit included in the electronic device.

5 is a flowchart illustrating an operation example of a correction interval determination circuit of the temperature compensation circuit in the electronic device shown in FIG.

FIG. 6 is an explanatory diagram illustrating a determination process performed by a correction interval determination circuit.

FIG. 7 is a circuit diagram showing an example of a CMOS oscillation circuit which is an oscillation circuit to be temperature-compensated by the temperature compensation circuit according to the embodiment of the present invention.

FIG. 8 is a circuit diagram showing an example of an oscillation circuit that is a target of temperature compensation of the temperature compensation circuit according to the embodiment of the present invention and that uses a bipolar transistor.

FIG. 9 is a configuration diagram showing a configuration of a conventional temperature compensation circuit together with a configuration of an oscillation circuit.

FIG. 10 is a diagram showing a lapse of time in the case where the conventional temperature compensation circuit intermittently performs the temperature compensation operation according to a temperature change.

[Explanation of symbols]

7 Oscillation circuit 11 Temperature compensation circuit 12 Correction interval determination circuit 13 Correction interval register 14 Selection circuit 15 Compensation operation control circuit 16 Temperature sensor 17 Temperature-digital signal conversion circuit 18 Correction value determination circuit 19 Correction value register

Claims (8)

[Claims] 1. A temperature compensation circuit for an oscillation circuit, which detects the ambient temperature of the oscillation circuit with a temperature sensor and compensates the temperature of the oscillation circuit based on the detected temperature, the time of the temperature detected by the temperature sensor. And a correction interval determined by the correction interval determining means for determining a predetermined correction interval for correcting the oscillation frequency of the oscillation circuit according to the obtained temperature change. A temperature compensating circuit for an oscillation circuit, comprising: an oscillation frequency control unit that takes in the detection temperature of the temperature sensor for each time and adjusts the oscillation frequency of the oscillation circuit according to the detection temperature. 2. The correction interval determination means determines the correction interval smaller when the obtained temperature change exceeds a set value, and determines the correction interval larger when the temperature change falls below the set value. The temperature compensation circuit for an oscillation circuit according to claim 1, wherein 3. The correction interval determining means is adapted to receive a signal generated when the main power supply is turned on or off, and when the signal is received,
The temperature compensation circuit for an oscillation circuit according to claim 1 or 2, wherein a predetermined correction interval is determined. 4. The temperature compensation of the oscillation circuit according to claim 3, wherein the signal received by the correction interval determining means is a signal from a main power supply voltage detection circuit that monitors turning on or off of the main power supply. circuit. 5. The correction interval determination means is configured such that a current consumption priority mode that prioritizes reduction of current consumption and a correction priority mode that prioritizes accuracy of the oscillation frequency of the oscillation circuit are set from the outside. The temperature compensation circuit for an oscillation circuit according to claim 1, wherein the temperature compensation circuit is a temperature compensation circuit. 6. The correction interval determination means, when the consumption current priority mode is set, compares the obtained temperature change with a first permissible range, and if it falls within the first permissible range. Maintain the currently determined correction interval, and if the temperature change exceeds the first allowable range, decrease the currently determined correction interval so that the temperature change does not exceed the first allowable range. When the value is below the range, the correction interval currently determined is increased, and when the correction priority mode is set, the obtained temperature change is compared with the second allowable range, When the temperature change exceeds the second allowable range, the correction interval that is currently determined is maintained when the temperature falls within the second allowable range, and the correction interval that is currently determined is exceeded when the temperature change exceeds the second allowable range. Depending on the prescribed supplement Was reduced to interval,
6. The temperature compensating circuit for an oscillator circuit according to claim 5, wherein when the temperature change falls below the second allowable range, the currently determined correction interval is increased. 7. A method for temperature compensation of an oscillation circuit, wherein the temperature of the oscillation circuit is detected by a temperature sensor, and the temperature of the oscillation circuit is compensated based on the detected temperature. Temperature change is determined, a predetermined correction interval for correcting the oscillation frequency of the oscillation circuit is determined according to the calculated temperature change, and the temperature detected by the temperature sensor is captured at each of the determined correction intervals. A temperature compensating method for an oscillation circuit, wherein the oscillation frequency of the oscillation circuit is adjusted according to the detected temperature. 8. The correction interval is determined to be smaller when the calculated temperature change exceeds a set value and larger when the calculated temperature change is below the set value. A method for compensating a temperature of an oscillator circuit according to.