Electronic device, electronic equipment, electronic equipment system, air conditioning system and air conditioning apparatus

Abstract

To provide an electronic device that can itself improve a frequency accuracy of an operation clock generated by the electronic device.SOLUTION: An electronic device 1 has: an oscillation circuit 16 for generating an operation clock; a reception circuit 11 for receiving a communication signal synchronized with a high-accuracy clock from an upstream device 3 that operates with a high-accuracy clock having a frequency accuracy higher than a frequency accuracy of the operation clock; a measurement circuit 17 for measuring a pulse width, which is a width of a pulse included in the communication signal, based on the operation clock; a memory 13 for storing a reference value of the pulse width; and a correction circuit 18 for correcting a frequency of the operation clock based on a result of comparing a measured value of the pulse width measured by the measurement circuit 17 with the reference value.SELECTED DRAWING: Figure 2

Description

[Technical Field]

[0001] The present disclosure relates to an electronic device, an electronic equipment, an electronic equipment system, an air conditioning system, and an air conditioning apparatus. [Background technology]

[0002] A technique is known in which a low-precision oscillator is used in the oscillation circuit of a driver IC, and the oscillation frequency of the driver IC is corrected based on the results of measuring the frequency of the clock output from the driver IC using a microcomputer (see, for example, Patent Document 1). [Prior art documents] [Patent documents]

[0003] [Patent Document 1] Japanese Patent Application Laid-Open No. 2006-31585 Summary of the Invention [Problem to be solved by the invention]

[0004] The conventional technology has had the problem of imposing a heavy processing load on other devices that control the electronic device whose clock oscillation frequency is to be corrected.

[0005] The present disclosure has been made in consideration of these points, and aims to enable an electronic device itself to improve the frequency accuracy of the clock it generates. [Means for solving the problem]

[0006] An electronic device according to a first aspect of the present disclosure includes an oscillator circuit that generates an operating clock, a receiver circuit that receives a communication signal synchronized with a high-precision clock from an upstream device that operates on the high-precision clock with a frequency precision higher than that of the operating clock, a measurement circuit that measures a pulse width that is the width of a pulse included in the communication signal based on the operating clock, a memory that stores a reference value for the pulse width, and a correction circuit that corrects the frequency of the operating clock based on a result of comparing the pulse width measured by the measurement circuit with the reference value. This allows the electronic device itself to improve the frequency precision of the operating clock generated by the electronic device.

[0007] The oscillator circuit may have a trimming circuit that changes the frequency of the operating clock based on an input voltage, and the correction circuit may correct the frequency of the operating clock by inputting a voltage based on the difference between the measured value and the reference value to the trimming circuit, thereby enabling the electronic device to correct the frequency over a wide frequency range.

[0008] The oscillator circuit may have a reference clock generation circuit that generates a reference clock having a frequency different from that of the operating clock, and a phase locked loop circuit that generates the operating clock by dividing or multiplying the reference clock, and the correction circuit may correct the frequency of the operating clock by changing an internal parameter of the phase locked loop based on a result of comparing the measured value with the reference value, thereby enabling the electronic device to correct the frequency with high precision.

[0009] The oscillator circuit may include a trimming circuit that changes the frequency of the operating clock based on an input voltage, a reference clock generation circuit that generates a reference clock having a frequency different from that of the operating clock, and a phase locked loop circuit that generates the operating clock by dividing or multiplying the reference clock, and the correction circuit may correct the frequency of the operating clock by inputting a differential voltage based on the difference between the measurement value and the reference value to the trimming circuit, and then correct the frequency of the operating clock by changing an internal parameter of the phase locked loop based on a result of comparing the measurement value obtained by measuring the pulse width of the new communication signal with the reference value. This allows the electronic device to correct frequencies with high precision over a wide frequency range.

[0010] The correction circuit may correct the frequency of the operating clock at a first resolution by inputting the differential voltage to the trimming circuit, and then correct the frequency of the operating clock at a second resolution higher than the first resolution by changing an internal parameter of the phase-locked loop, thereby enabling the electronic device to correct the frequency with high resolution and high accuracy over a wide frequency range.

[0011] The electronic device may further include a data acquisition circuit that acquires setting data for the reference value and stores the acquired reference value in the memory, thereby enabling the electronic device to correct the frequency regardless of the communication speed of the communication signal transmitted by the upstream device.

[0012] The memory may store a plurality of reference value candidates, and the correction circuit may compare the measured value with the reference value selected from the plurality of reference value candidates based on the pulse width measured by the measurement circuit. This allows the electronic device to correct the frequency even when a plurality of communication speeds are assumed as the communication speed of the communication signal transmitted by the upstream device.

[0013] The electronic device may further include a data acquisition circuit that acquires instruction data including an instruction to correct the frequency of the operating clock, and the correction circuit may correct the frequency of the operating clock in response to the reception of the instruction data by the receiving circuit, thereby enabling the electronic device to correct the frequency when a user of an electronic device equipped with the electronic device wants the electronic device to correct the frequency.

[0014] The electronic device may further include a temperature sensor for measuring an internal temperature of the electronic device, and the correction circuit may correct the frequency of the operation clock when a deviation of the temperature measured by the temperature sensor from a reference temperature exceeds a threshold value, thereby reducing a frequency deviation of the operation clock of the electronic device caused by temperature deviation.

[0015] The memory may further store an accumulated period during which the electronic device is in operation, and the correction circuit may correct the frequency of the operating clock when the accumulated period reaches a predetermined period, thereby reducing frequency deviation of the operating clock of the electronic device due to aging.

[0016] According to a second aspect of the present disclosure, there is provided an electronic device comprising: a first electronic device operating on a high-precision clock with a first frequency accuracy; and a second electronic device generating an operating clock with a second frequency accuracy lower than the first frequency accuracy, the second electronic device including an oscillator circuit for generating the operating clock, a receiver circuit for receiving a communication signal synchronized with the high-precision clock from the first electronic device, a measurement circuit for measuring a pulse width of a pulse included in the communication signal based on the operating clock, a memory for storing a reference value for the pulse width included in the communication signal, and a correction circuit for correcting the frequency of the operating clock based on a result of comparing the pulse width measured by the measurement circuit with the reference value. This makes it possible to improve the frequency accuracy of the electronic device included in the electronic device while suppressing an increase in the cost of the electronic device.

[0017] According to a third aspect of the present disclosure, there is provided an electronic device system comprising a first electronic device and a second electronic device capable of communicating with the first electronic device, the first electronic device having a first electronic device operating on a high-precision clock with a first frequency accuracy, the second electronic device having a second electronic device generating an operating clock with a second frequency accuracy lower than the first frequency accuracy, the second electronic device having an oscillator circuit generating the operating clock, a receiver circuit receiving a communication signal from the first electronic device synchronized with the high-precision clock, a measurement circuit measuring a pulse width of a pulse included in the communication signal based on the operating clock, a memory storing a reference value for the pulse width included in the communication signal, and a correction circuit correcting the frequency of the operating clock based on a result of comparing the pulse width measured by the measurement circuit with the reference value. This arrangement improves the frequency accuracy of the electronic device included in the second electronic device while minimizing cost increases for the second electronic device.

[0018] A fourth aspect of the present disclosure provides an air conditioning system including an indoor unit and an outdoor unit, wherein one of the indoor unit and the outdoor unit has a first electronic device that operates on a high-precision clock with a first frequency accuracy, and the other of the indoor unit and the outdoor unit has a second electronic device that generates an operating clock with a second frequency accuracy lower than the first frequency accuracy, the second electronic device having an oscillator circuit that generates the operating clock, a receiving circuit that receives a communication signal synchronized with the high-precision clock from an apparatus having the first electronic device, a measurement circuit that measures a pulse width of a pulse included in the communication signal based on the operating clock, a memory that stores a reference value for the pulse width included in the communication signal, and a correction circuit that corrects the frequency of the operating clock based on a result of comparing the pulse width measured by the measurement circuit with the reference value. This allows for improved frequency accuracy of the electronic device included in the indoor unit or the outdoor unit while minimizing cost increases for the indoor unit or the outdoor unit in the air conditioning system.

[0019] A fifth aspect of the present disclosure provides an air conditioner capable of communicating with a communication device equipped with a first electronic device that operates on a high-precision clock with a first frequency accuracy, the air conditioner including a second electronic device that generates an operating clock with a second frequency accuracy lower than the first frequency accuracy, the second electronic device including an oscillator circuit that generates the operating clock, a receiver circuit that receives a communication signal from the communication device synchronized with the high-precision clock, a measurement circuit that measures a pulse width of a pulse included in the communication signal based on the operating clock, a memory that stores a reference value for the pulse width included in the communication signal, and a correction circuit that corrects the frequency of the operating clock based on a result of comparing the pulse width measured by the measurement circuit with the reference value. This allows for improved frequency accuracy of the electronic device included in the electronic device while suppressing increases in the cost of the air conditioner. [Brief explanation of the drawings]

[0020] [Figure 1] FIG. 1 is a diagram illustrating an overview of an electronic device 100. [Figure 2] 1 is a diagram showing a configuration of an electronic device 1. FIG. [Figure 3] FIG. 2 is a diagram illustrating an example of the configuration of a phase locked loop 163. [Figure 4] 10A and 10B are diagrams illustrating examples of pulses that are targets of measurement by the measurement circuit 17. FIG [Figure 5] 10 is a flowchart showing the flow of processing for correcting the operating clock in the electronic device 1. [Figure 6] 10 is a diagram showing another example of the configuration of the electronic device 1. FIG. [Figure 7] 1 is a diagram showing an embodiment of an electronic device 1. FIG. [Figure 8] 10A and 10B are diagrams illustrating another embodiment of the electronic device 1. [Figure 9] 1 is a diagram showing the configuration of an electronic device 200. FIG. [Figure 10] 1 is a diagram showing the configuration of an electronic device 300. FIG. [Figure 11] FIG. 4 is a diagram showing the configuration of an electronic device 400. [Figure 12] FIG. 2 is a diagram showing the configuration of an air conditioning system S1. [Figure 13] FIG. 2 is a diagram showing the configuration of an air conditioning system S2. [Figure 14] FIG. 2 is a diagram showing the configuration of an air conditioning system S3. DETAILED DESCRIPTION OF THE INVENTION

[0021] [Overview of Electronic Device 100] 1 is a diagram illustrating an overview of an electronic device 100. The electronic device 100 is a device having an electric circuit that operates based on a clock, such as an air conditioner. The electronic device 100 has an electronic device 1, an oscillator 2, an upstream device 3, and an oscillator 4.

[0022] The electronic device 1 is, for example, a semiconductor device that operates based on an operating clock generated by oscillating an oscillator 2. The electronic device 1 generates an operating clock by dividing or multiplying the oscillation signal generated by the oscillator 2, and operates an internal circuit using the operating clock. The electronic device 1 can make the frequency accuracy of the operating clock higher than the frequency accuracy of the oscillator 2 by correcting the frequency of the operating clock using a communication signal input from an upstream device 3.

[0023] The resonator 2 oscillates while connected to the electronic device 1. The resonator 2 is, for example, a ceramic resonator. The accuracy of the oscillation frequency of the resonator 2 is lower than the accuracy of the oscillation frequency of the oscillator 4, for example, ±0.5%.

[0024] The upstream device 3 is a device capable of transmitting a communication signal to the electronic device 1. The upstream device 3 operates on a high-precision clock with a higher frequency accuracy than the frequency accuracy of the operating clock generated by the electronic device 1. The upstream device 3 generates a communication signal based on the high-precision clock generated by oscillating an oscillator 4. The communication signal is, for example, a serial signal such as a UART (Universal Asynchronous Receiver Transmitter) or SPI (Serial Peripheral Interface).

[0025] The oscillator 4 provides an oscillation signal to the upstream device 3. The oscillator 4 is, for example, a crystal oscillator. The frequency accuracy of the oscillator 4 is higher than that of the resonator 2, for example, ±0.001%. The oscillator 4 may be a temperature compensated crystal oscillator (TCXO) or an oven-controlled crystal oscillator. Note that instead of the oscillator 4, a crystal resonator with a higher frequency accuracy than the resonator 2 may be used. The upstream device 3 operates using a high-precision clock based on the oscillation signal provided by the oscillator 4.

[0026] The upstream device 3 generates a communication signal using a high-precision clock. When the design value of the communication speed of the communication path between the electronic device 1 and the upstream device 3 is 9600 bps, the design value of the minimum pulse width of the communication signal is 104.16 μs, and when the communication speed of the communication path is 19200 bps, the design value of the minimum pulse width of the communication signal is 52.08 μs. In the following description, the design value of the pulse width of the communication signal transmitted by the upstream device 3 is referred to as the reference value.

[0027] The electronic device 1 measures the pulse width of the received communication signal based on the operating clock generated by oscillating the oscillator 2. If the operating clock of the electronic device 1 has the same accuracy as the high-precision clock of the upstream device 3, the measured pulse width will match the above-mentioned reference value. However, if the frequency of the operating clock of the electronic device 1 is lower than the design frequency, the pulse width measured by the electronic device 1 will be shorter than the reference value. If the frequency of the operating clock of the electronic device 1 is higher than the design frequency, the pulse width measured by the electronic device 1 will be longer than the reference value. The electronic device 1 compares the measured pulse width value with the reference value and corrects the operating clock based on the magnitude of the difference between the measured value and the reference value.

[0028] By configuring the electronic device 1 in this way, even if the frequency accuracy of the resonator 2 used by the electronic device 1 to generate an operating clock is low, the frequency accuracy of the operating clock generated by the electronic device 1 based on the resonator can be made higher than the frequency accuracy of the resonator 2. As a result, high frequency accuracy is not required of the resonator 2, and the cost of the resonator 2 can be reduced.

[0029] [Configuration of Electronic Device 1] 2 is a diagram showing the configuration of the electronic device 1. The electronic device 1 has a receiving circuit 11, a data acquisition circuit 12, a memory 13, a temperature sensor 14, an AD converter 15, an oscillation circuit 16, a measurement circuit 17, and a correction circuit 18. Some or all of the functions of the receiving circuit 11, the data acquisition circuit 12, the measurement circuit 17, and the correction circuit 18 may be realized by a processor that executes a program, or may be realized by a hardware logic circuit.

[0030] The receiving circuit 11 receives a communication signal synchronized with the high-precision clock generated by the upstream device 3 from the upstream device 3. The receiving circuit 11 has, for example, a receiving buffer, and inputs a digital signal in a state in which the rising and falling timings of the received communication signal are maintained to the measurement circuit 17. The receiving circuit 11 extracts data contained in the communication signal based on the operating clock output from the oscillation circuit 16, and inputs the extracted data to the data acquisition circuit 12.

[0031] The data acquisition circuit 12 acquires the data output by the receiving circuit 11. The data acquisition circuit 12 acquires, for example, setting data for a reference value of the pulse width of a communication signal transmitted by the upstream device 3. The data acquisition circuit 12 stores the reference value included in the acquired setting data in the memory 13.

[0032] The data acquisition circuit 12 may acquire instruction data including an instruction to correct the frequency of the operating clock. The instruction is input, for example, by a user of the electronic device 100 operating an operation unit of the electronic device 100. The data acquisition circuit 12 acquires the instruction data input via the operation unit of the electronic device 100. For example, the data acquisition circuit 12 acquires the instruction data included in a communication signal transmitted by the upstream device 3 that has acquired the instruction data input via the operation unit.

[0033] The memory 13 is, for example, a random access memory (RAM). The memory 13 may also include a read only memory (ROM). The memory 13 stores, for example, a reference value for the pulse width of a communication signal transmitted by the upstream device 3. The memory 13 may further store an accumulated period during which the electronic device 1 is operating.

[0034] The temperature sensor 14 is a sensor that measures the temperature around or inside the electronic device 1. The temperature sensor 14 includes, for example, a silicon diode, and outputs a voltage corresponding to the temperature.

[0035] The AD converter 15 converts the voltage output by the temperature sensor 14 into temperature data, which is digital data indicating the temperature. The AD converter 15 inputs the temperature data to the correction circuit 18.

[0036] The oscillation circuit 16 outputs an operating clock based on an oscillation signal generated by oscillating the oscillator 2. The oscillation circuit 16 includes a reference clock generation circuit 161, a trimming circuit 162, and a phase locked loop circuit 163.

[0037] The reference clock generation circuit 161 has an amplifier for oscillating the oscillator 2, and generates a reference clock by oscillating the oscillator 2 at the oscillation frequency of the oscillator 2. The reference clock generation circuit 161 generates a reference clock having a different frequency from the operating clock output by the phase locked loop 163. The reference clock generation circuit 161 inputs the generated reference clock to the phase locked loop 163.

[0038] The trimming circuit 162 changes the frequency of the operating clock based on the input voltage. The trimming circuit 162 is a circuit for adjusting the frequency of the reference clock generated by the reference clock generation circuit 161, and includes, for example, a variable capacitance diode whose capacitance decreases as the applied voltage increases. The trimming circuit 162 changes the frequency of the reference clock by changing the capacitance of the oscillation loop formed by the amplifier of the reference clock generation circuit 161 according to the voltage input from the correction circuit 18.

[0039] The phase locked loop 163 generates an operating clock by dividing or multiplying the reference clock generated by the reference clock generating circuit 161. The phase locked loop 163 has, for example, a PLL (Phase Locked Loop) having a VCO (Voltage Controlled Oscillator). The phase locked loop 163 has a register in which internal parameters of the PLL are set, and the VCO outputs an operating clock of a frequency according to the internal parameters set in the register. The phase locked loop 163 can adjust the frequency with a higher resolution than the frequency adjustment resolution of the trimming circuit 162, and can adjust the operating clock with a resolution of, for example, 0.3 ppm.

[0040] 3 is a diagram showing an example of the configuration of the phase locked loop 163. The phase locked loop 163 shown in FIG.

[0041] Divider 31 divides the reference clock by a division ratio M (M is a natural number). Divider 31 inputs the divided clock to phase comparator 33. Divider 32 divides the operating clock output by VCO 35 by a division ratio N (N is a natural number). Divider 32 inputs the divided clock to phase comparator 33.

[0042] Phase comparator 33 calculates the phase difference between the clock input from frequency divider 31 and the clock input from frequency divider 32, and inputs a voltage corresponding to the phase difference to LPF 34. LPF 34 is a low-pass filter that removes high-frequency components from the voltage input from phase comparator 33.

[0043] The VCO 35 outputs an operating clock having a frequency corresponding to the voltage input from the LPF 34. The frequency of the operating clock output by the VCO 35 is determined by multiplying the frequency of the reference clock by the division ratio N / the division ratio M. The division ratios M and N are internal parameters of the phase locked loop 163, and the correction circuit 18 can fine-tune the frequency of the operating clock by setting the division ratios M and N in the registers of the phase locked loop 163.

[0044] The measurement circuit 17 measures the width of a pulse included in the communication signal based on the operating clock output by the oscillation circuit 16. The measurement circuit 17 has, for example, a timer that counts up based on the operating clock, and measures the time between multiple level change points as the pulse width by counting up from one level change point of the communication signal to another level change point. The measurement circuit 17 inputs the measured pulse width value to the correction circuit 18.

[0045] 4 is a diagram showing an example of a pulse to be measured by the measurement circuit 17. For example, the measurement circuit 17 measures the time T1 from the falling edge to the rising edge of the communication signal. The measurement circuit 17 may measure the time T2 from the rising edge to the falling edge of the communication signal, or may measure the time T3 from the falling edge to the next falling edge of the communication signal.

[0046] The measurement circuit 17 may measure the cumulative period during which the electronic device 1 is operating. The measurement circuit 17 measures the cumulative time since the start of operation, for example, by using a timer that operates based on an operation clock, and stores the measured cumulative time in the memory 13 periodically (for example, once a day).

[0047] The correction circuit 18 corrects the frequency of the operating clock based on the result of comparing the measured value of the pulse width measured by the measurement circuit 17 with a reference value. The correction circuit 18 corrects the frequency of the operating clock, for example, by inputting a voltage based on the difference between the measured value and the reference value to the trimming circuit 162.

[0048] If the measured value is greater than the reference value, the correction circuit 18 determines that the frequency of the operating clock is higher than the frequency of the high-precision clock. Therefore, the correction circuit 18 applies a voltage to the trimming circuit 162 that is smaller than the voltage previously applied to the trimming circuit 162, thereby increasing the capacitance of the variable capacitance diode, thereby lowering the frequency of the reference clock generated by the reference clock generation circuit 161. As a result, the frequency of the operating clock also decreases.

[0049] If the measured value is smaller than the reference value, the correction circuit 18 determines that the frequency of the operating clock is lower than the frequency of the high-precision clock. Therefore, the correction circuit 18 applies a voltage to the trimming circuit 162 that is greater than the voltage previously applied to the trimming circuit 162, thereby reducing the capacitance of the variable capacitance diode and increasing the frequency of the reference clock generated by the reference clock generation circuit 161. As a result, the frequency of the operating clock also increases. If the difference between the measured value and the reference value is within a predetermined range in which a change in the operating clock frequency is unnecessary, the correction circuit 18 maintains the voltage previously applied to the trimming circuit 162, thereby not changing the operating clock frequency.

[0050] The range of frequencies that can be changed by trimming circuit 162 is larger than the range of frequencies that can be changed by changing the internal parameters of the PLL. Therefore, correcting the frequency of the operating clock by correction circuit 18 using trimming circuit 162 is suitable when the deviation of the operating clock from the reference value is relatively large.

[0051] The correction circuit 18 can also correct the frequency of the operating clock by changing the internal parameters of the phase locked loop 163 based on the result of comparing the measured value with the reference value. If the measured value is greater than the reference value, the correction circuit 18 increases the frequency of the operating clock, for example, by increasing the division ratio N / division ratio M of the phase locked loop 163. If the measured value is smaller than the reference value, the correction circuit 18 decreases the frequency of the operating clock, for example, by decreasing the division ratio N / division ratio M of the phase locked loop 163.

[0052] The frequency resolution that can be corrected by changing the internal parameters of the phase locked loop 163 is higher than the frequency resolution that can be corrected by changing the voltage applied to the trimming circuit 162. Therefore, correcting the frequency of the operating clock by the correction circuit 18 using the internal parameters of the phase locked loop 163 is suitable for fine-tuning the frequency.

[0053] The correction circuit 18 may correct the frequency of the operating clock by inputting a differential voltage based on the difference between the measured value and a reference value to the trimming circuit 162, and then correct the frequency of the operating clock by changing the internal parameters of the phase locked loop 163 based on the result of comparing the measured value obtained by measuring the pulse width of a new communication signal with the reference value. In other words, the correction circuit 18 corrects the frequency of the operating clock at a first resolution by inputting the differential voltage to the trimming circuit 162, and then corrects the frequency of the operating clock at a second resolution higher than the first resolution by changing the internal parameters of the phase locked loop 163.

[0054] By operating in this manner, the correction circuit 18 can correct the frequency difference corresponding to the difference between the measured value and the reference value even if the frequency difference that needs to be corrected exceeds the range of frequencies that can be corrected with the second resolution by the phase-locked loop 163. Thus, the correction circuit 18 can correct the frequency of the operating clock with high precision with the second resolution.

[0055] The communication speed of the communication path between the electronic device 1 and the upstream device 3 may vary depending on the electronic device 100. The communication speed may also change depending on the operation mode. The pulse width measured by the measurement circuit 17 may be a pulse width corresponding to one bit of the communication signal, or may be a pulse width corresponding to two or more bits. Therefore, the memory 13 may store multiple reference value candidates, and the correction circuit 18 may compare the measured value with a reference value selected from the multiple reference value candidates based on the pulse width measured by the measurement circuit 17.

[0056] As an example, if the communication speed of the communication path between the electronic device 1 and the upstream device 3 is assumed to be one of 9600 bps, 14400 bps, and 19200 bps, the memory 13 stores the following as candidate reference values: a 1-bit pulse width of 104.16 μs at 9600 bps, a 2-bit pulse width of 208.32 μs at 9600 bps, a 1-bit pulse width of 69.44 μs at 14400 bps, and a 2-bit pulse width of 138.88 μs at 14400 bps.

[0057] Correction circuit 18 compares the measured value with the reference value, using as the reference value the reference value candidate that indicates the pulse width closest to the pulse width indicated by the measured value from among the multiple reference value candidates stored in memory 13. By configuring correction circuit 18 in this way, correction circuit 18 can correct the operating clock based on the communication signal even if the pulse width of the communication signal is variable.

[0058] The correction circuit 18 corrects the frequency of the operating clock when a preset condition is satisfied. For example, the correction circuit 18 corrects the frequency of the operating clock in response to the reception of instruction data by the receiving circuit 11. This allows, for example, a user of the electronic device 100 to perform an operation for correction when using the electronic device 100 for an application requiring high accuracy, thereby improving the accuracy of the operating clock of the electronic device 1.

[0059] The correction circuit 18 may correct the frequency of the operating clock when the deviation of the temperature measured by the temperature sensor 14 from the reference temperature is equal to or greater than a threshold value. This allows the accuracy of the frequency of the operating clock of the electronic device 1 to be maintained high even when the temperature of the environment in which the electronic device 100 is used changes. If the temperature deviation is less than the threshold value, the correction circuit 18 does not need to compare the measured value with the reference value. If the temperature deviation is small, the correction circuit 18 does not perform the correction process, thereby reducing the power consumed by the correction circuit 18.

[0060] The correction circuit 18 may correct the frequency of the operating clock when the accumulated period since the electronic device 1 started operating reaches a predetermined period. For example, the correction circuit 18 corrects the frequency of the operating clock every time one month has passed since the electronic device 1 started operating. This allows the correction circuit 18 to maintain high accuracy of the frequency of the operating clock of the electronic device 1 even if the electrical characteristics of the electronic device 1 or the resonator 2 change over time.

[0061] [Processing flow in electronic device 1] Fig. 5 is a flowchart showing the flow of processing for correcting the operating clock in the electronic device 1. The processing shown in the flowchart in Fig. 5 is executed by a processor or circuit functioning as the measurement circuit 17 and the correction circuit 18. The processing may be executed by the processor and the circuit working together.

[0062] The correction circuit 18 determines whether the data acquisition circuit 12 has acquired instruction data including an instruction to correct the frequency (S11). If the data acquisition circuit 12 has acquired the instruction data (YES in S11), the correction circuit 18 causes the measurement circuit 17 to measure the pulse width of the communication signal (S14).

[0063] If the data acquisition circuit 12 has not acquired the instruction data (NO in S11), the correction circuit 18 compares the temperature indicated by the temperature data input from the AD converter 15 with a reference temperature and calculates the temperature deviation. The correction circuit 18 determines whether the temperature deviation is equal to or greater than a first threshold value (S12). If the temperature deviation is equal to or greater than the first threshold value (YES in S12), the correction circuit 18 causes the measurement circuit 17 to measure the pulse width of the communication signal (S14).

[0064] If the temperature deviation is less than the first threshold value (NO in S12), correction circuit 18 determines whether a predetermined period has passed since the previous frequency correction by referring to the cumulative period stored in memory 13 (S13). If the predetermined period has passed (YES in S13), correction circuit 18 causes measurement circuit 17 to measure the pulse width of the communication signal (S14).

[0065] When the measurement circuit 17 measures the pulse width of the communication signal, the correction circuit 18 compares the measured value with a reference value stored in the memory 13 to calculate a difference value (S15). If the difference value is equal to or greater than the second threshold value (YES in S16), the correction circuit 18 corrects the frequency of the reference clock generated by the reference clock generation circuit 161 with the first resolution by changing the voltage input to the trimming circuit 162 according to the difference value (S17). If the difference value is less than the second threshold value (NO in S16), the correction circuit 18 ends the correction process.

[0066] After correcting the frequency of the reference clock, correction circuit 18 causes measurement circuit 17 to measure the pulse width of the communication signal (S18). If the difference between the measured value and the reference value is equal to or greater than the second threshold (YES in S19), correction circuit 18 corrects the frequency of the operating clock with the second resolution by changing the internal parameters of the PLL (S20). If the difference between the measured value and the reference value is less than the second threshold (NO in S19), correction circuit 18 ends the correction process.

[0067] 5, the processes in S11, S12, and S13 may be performed or not, and the order of these processes may be arbitrary. The electronic device 1 may continue to perform the processes from S14 to S20 without performing the processes from S11 to S13.

[0068] [Other configuration examples of electronic device 1] Fig. 6 is a diagram showing another example of the configuration of the electronic device 1. In the electronic device 1 shown in Fig. 2, the data acquisition circuit 12 acquires the setting data and instruction data via the receiving circuit 11, but the data acquisition circuit 12 may acquire the setting data and instruction data via a communication path different from the communication path over which the communication signal is transmitted.

[0069] [Example of Electronic Device 1] Fig. 7 is a diagram showing an embodiment of the electronic device 1. The electronic device 1 shown in Fig. 7 has a CPU (Central Processing Unit) 20, and a receiving circuit 11, a memory 13, an AD converter 15, an oscillation circuit 16, a measurement circuit 17, and a correction circuit 18 are connected to a data bus DB1 of the CPU 20. In this embodiment, the correction circuit 18 obtains a measurement value indicating a pulse width from the measurement circuit 17 via the data bus DB1, and sets data for correcting the operating clock in the oscillation circuit 16 via the data bus DB1.

[0070] Fig. 8 is a diagram showing another embodiment of the electronic device 1. The electronic device 1 shown in Fig. 8 differs from the electronic device 1 shown in Fig. 7 in that it has a data bus DB2 in addition to the data bus DB1. An oscillation circuit 16, a measurement circuit 17, and a correction circuit 18 are connected to the data bus DB2.

[0071] The oscillator circuit 16, the measurement circuit 17, and the correction circuit 18 transmit and receive data for correcting the operating clock via the data bus DB2, and transmit and receive other data via the data bus DB1. Specifically, the measurement circuit 17 notifies the correction circuit 18 of the measurement value of the pulse width of the communication signal via the data bus DB2, and the correction circuit 18 notifies the oscillator circuit 16 of the data for correcting the operating clock via the data bus DB2. By the oscillator circuit 16, the measurement circuit 17, and the correction circuit 18 correcting the operating clock frequency using the data bus DB2, the CPU 20 and the data bus DB1 are not used for the frequency correction process, and therefore a decrease in the performance of the CPU 20 can be prevented.

[0072] [Modifications of the configuration of electronic devices] 9 is a diagram showing the configuration of an electronic device 200. While the electronic device 100 shown in FIG. 1 includes one electronic device 1, the electronic device 200 differs from the electronic device 100 in that it further includes an electronic device 1A and an electronic device 1B. The electronic device 1A generates a reference clock based on an oscillator 2A that, like the oscillator 2, has lower frequency accuracy than the oscillator 4, and the electronic device 1B generates a reference clock based on an oscillator 2B that, like the oscillator 2, has lower frequency accuracy than the oscillator 4.

[0073] The electronic device 1 functions as an upstream device relative to the electronic device 1A, and the electronic device 1A corrects the frequency of its operating clock based on the result of measuring the pulse width of a communication signal input from the electronic device 1. The electronic device 1A functions as an upstream device relative to the electronic device 1B, and the electronic device 1B corrects the frequency of its operating clock based on the result of measuring the pulse width of a communication signal input from the electronic device 1. According to the configuration shown in the electronic device 200, even if more electronic devices 1 are mounted than the number of communication signals that the upstream device 3 can output, the frequency accuracy of the operating clocks of the multiple electronic devices 1 can be improved.

[0074] FIG. 10 is a diagram showing the configuration of an electronic device 300. Like the electronic device 200, the electronic device 300 also has an electronic device 1A and an electronic device 1B. However, the electronic device 300 differs from the electronic device 200 shown in FIG. 9 in that the electronic device 1A and the electronic device 1B are directly connected to an upstream device 3. Like the electronic device 1, the electronic device 1A and the electronic device 1B correct the operating clock based on the oscillator 2A by measuring the pulse width of a communication signal received from the upstream device 3. According to the configuration shown in the electronic device 300, even if the electronic device 1 does not have a function of outputting a communication signal, the frequency accuracy of each operating clock of the multiple electronic devices 1 can be improved.

[0075] 11 is a diagram showing the configuration of an electronic device 400. In the electronic device 400, the electronic device 1 functions as an upstream device relative to the electronic devices 1A and 1B. The electronic devices 1A and 1B measure the pulse width of a communication signal output by the electronic device 1, and thereby correct the operating clocks of the electronic devices 1A and 1B. With the configuration shown in the electronic device 400, even if the upstream device 3 can output only one communication signal and the electronic devices 1A and 1B cannot output any communication signals, the frequency accuracy of the operating clocks of the multiple electronic devices 1 can be improved.

[0076] [First example of air conditioning system] 12 is a diagram showing the configuration of an air conditioning system S1. The air conditioning system S1 is an example of an electronic device system having an indoor unit 500, which is a first electronic device, and an outdoor unit 600, which is a second electronic device. The indoor unit 500 has a first electronic device that operates on a high-precision clock with a first frequency accuracy, and the outdoor unit 600 has a second electronic device that operates on an operating clock with a second frequency accuracy that is lower than the first frequency accuracy. The first electronic device corresponds to the upstream device 3 in FIG. 1, and the second electronic device corresponds to the electronic device 1 in FIG. 1.

[0077] The outdoor unit 600 has a compressor device 610 and a fan device 620 as second electronic devices. The outdoor unit 600 also has an oscillator 630 and an resonator 640. The compressor device 610 is an electronic device for controlling the compressor. The fan device 620 is an electronic device for controlling the fan. The compressor device 610 operates using an oscillator 630 with a frequency accuracy lower than that of an oscillator included in the indoor unit 500. The fan device 620 operates using an oscillator 640 with a frequency accuracy lower than that of an oscillator included in the indoor unit 500.

[0078] The compressor device 610 has the same function as the electronic device 1 shown in Fig. 1, and corrects the frequency of the operating clock generated by the oscillation of the oscillator 630 by measuring the pulse width of the communication signal received from the indoor unit 500. The fan device 620 also has the same function as the electronic device 1 shown in Fig. 1, and corrects the frequency of the operating clock generated by the oscillation of the oscillator 640 by measuring the pulse width of the communication signal received from the compressor device 610.

[0079] 1, the indoor unit 500 operates based on an oscillator with higher frequency accuracy than the oscillators 630 and 640. The indoor unit 500 has a PLL that generates an oscillation signal synchronized with a clock or signal supplied from a communication network, and may generate a communication signal based on the oscillation signal generated by the PLL. Because the frequency accuracy of the clock or signal supplied from the communication network is extremely high, the frequency accuracy of the oscillation signal synchronized with the clock or signal is higher than the frequency accuracy of the oscillators 630 and 640.

[0080] As an example, in response to receiving an operation to start operation, the indoor unit 500 transmits a communication signal including instruction data for correcting the frequency to the compressor device 610. When the compressor device 610 completes correction of the frequency of its own operating clock, it transmits a communication signal including instruction data for correcting the frequency to the fan device 620. This enables devices (e.g., inverters) included in the outdoor unit 600 to operate with an operating clock of an appropriate frequency while suppressing the cost of the oscillator of the outdoor unit 600. As a result, the compressor and fan operate at appropriate speeds, making it possible to reduce power consumption.

[0081] The compressor device 610 and the fan device 620 may correct the operating clock when they detect that the temperature of the outdoor unit 600 has become too high or too low and outside a predetermined range. For example, when the temperature deviation is equal to or greater than a first threshold, the compressor device 610 requests the indoor unit 500 to transmit a communication signal, and corrects the frequency of the operating clock based on the measured value of the pulse width of the communication signal transmitted by the indoor unit 500. This configuration is suitable for an outdoor unit 600 used outdoors where temperatures change drastically.

[0082] The indoor unit 500 may be connected to a communication network, and the first electronic device may have a PLL that generates an oscillation signal synchronized with a clock or signal supplied from the communication network. In this case, the first electronic device generates a communication signal based on the oscillation signal with a first frequency accuracy generated by the PLL.

[0083] Furthermore, the indoor unit 500 may have the upstream device 3 and the electronic device 1. In this case, the indoor unit 500 transmits a first communication signal based on the high-precision clock generated by the upstream device 3 to the electronic device 1, and transmits a second communication signal based on the high-precision clock generated by the upstream device 3 to the outdoor unit 600.

[0084] In the outdoor unit 600, the fan device 620 may receive a communication signal from the indoor unit 500, and the compressor device 610 may receive a communication signal from the fan device 620.

[0085] [Second example of air conditioning system] 13 is a diagram showing the configuration of an air conditioning system S2. The air conditioning system S2 differs from the first embodiment in that the outdoor unit 600 has a first electronic device that operates on a high-precision clock based on a first frequency accuracy, and the indoor unit 500 has a second electronic device that operates on an operating clock with a second frequency accuracy that is lower than the first frequency accuracy, but is otherwise the same as the first embodiment.

[0086] The outdoor unit 600 has a compressor device 610 and a fan device 620. As an example, the frequency accuracy of an oscillator 650 connected to the compressor device 610 is higher than that of an oscillator 640 connected to the fan device 620, and the compressor device 610 functions as the upstream device 3 shown in FIG. 1. The fan device 620 functions as the electronic device 1 shown in FIG. 1.

[0087] The compressor device 610 transmits a first communication signal based on the high-precision clock to the fan device 620, and transmits a second communication signal based on the high-precision clock to the indoor unit 500. The fan device 620 has the same function as the electronic device 1 shown in FIG. 1 , and corrects the frequency of the operating clock generated by the fan device 620 by measuring the pulse width of the communication signal received from the outdoor unit 600.

[0088] The second electronic device included in the indoor unit 500 has the same function as the electronic device 1 shown in Fig. 1, and corrects the frequency of the operating clock generated by the second electronic device by measuring the pulse width of the communication signal received from the outdoor unit 600. This enables the indoor unit 500 to operate at an appropriate frequency while keeping the cost of the oscillator low.

[0089] The frequency accuracy of the oscillator 640 connected to the fan device 620 may be higher than that of the oscillator 650 connected to the compressor device 610, and the fan device 620 may function as the upstream device 3 shown in Fig. 1. In this case, the fan device 620 transmits a communication signal, and the compressor device 610 and the indoor unit 500 correct their operating clocks based on the communication signal.

[0090] [Third example of air conditioning system] 14 is a diagram showing the configuration of an air conditioning system S3. The air conditioning system S3 has an indoor unit 500, which is an air conditioner connected to a communication device 700, and an outdoor unit 600, which is also an air conditioner that can communicate with the indoor unit 500. As an example, the communication device 700 is a router or an access point connected to a communication network (e.g., the Internet or a local area network), and transmits data indicating the status of the indoor unit 500 or the outdoor unit 600 to a server.

[0091] The communication device 700 has the upstream device 3 shown in Fig. 1 as a first electronic device that operates on a high-precision clock with a first frequency accuracy. The communication device 700 has a PLL that generates an oscillation signal synchronized with a clock or signal supplied from a communication network, and generates a communication signal based on the oscillation signal generated by the PLL. Because the frequency accuracy of the clock or signal supplied from the communication network is extremely high, the frequency accuracy of the oscillation signal generated by the PLL is higher than the frequency accuracy of the operating clock of the indoor unit 500 or the outdoor unit 600.

[0092] The indoor unit 500 and the outdoor unit 600 have the electronic device 1 shown in FIG. 2 as a second electronic device that operates at an operating clock with a lower frequency accuracy than the first frequency accuracy. The electronic device 1 of the indoor unit 500 corrects the frequency of the operating clock based on an oscillator possessed by the indoor unit 500 based on a communication signal received from the communication equipment 700. The electronic device 1 of the outdoor unit 600 corrects the frequency of the operating clock based on an oscillator possessed by the outdoor unit 600 based on a communication signal received from the indoor unit 500. This configuration allows the air conditioner S2 to use an oscillator with low frequency accuracy, thereby reducing costs while increasing the frequency accuracy of the operating clock.

[0093] In FIG. 14, the outdoor unit 600 is connected only to the indoor unit 500, but the outdoor unit 600 may also be connected to the communication device 700, and the outdoor unit 600 may correct the frequency of the operating clock based on the communication signal received from the communication device 700.

[0094] [Effects of Electronic Device 1] As described above, the electronic device 1 includes the measurement circuit 17 that measures the pulse width, which is the width of a pulse included in a communication signal transmitted from an upstream device, based on the operating clock, and the correction circuit 18 that corrects the frequency of the operating clock based on the result of comparing the pulse width measured by the measurement circuit 17 with a reference value. With the electronic device 1 configured in this way, the electronic device 1 itself, which has an oscillator 2 with relatively low frequency accuracy, can improve the frequency accuracy of the operating clock generated based on the oscillator.

[0095] The present disclosure has been described above using embodiments, but the technical scope of the present disclosure is not limited to the scope described in the above embodiments, and various modifications and changes are possible within the scope of the gist thereof. For example, all or part of the device can be configured by functionally or physically distributing or integrating in any unit. Furthermore, new embodiments resulting from any combination of multiple embodiments are also included in the embodiments of the present disclosure. The effects of the new embodiments resulting from the combination also have the effects of the original embodiments. [Explanation of symbols]

[0096] 1. Electronic Devices 2 oscillators 3 Upstream Device 4. Oscillators 11 Receiving circuit 12 Data acquisition circuit 13. Memory 14 Temperature Sensor 15 AD converter 16 Oscillator Circuit 17 Measurement circuit 18 Correction circuit 20 CPU 31 Frequency divider 32 frequency divider 33 Phase comparator 100 Electronic equipment 161 Reference clock generation circuit 162 Trimming circuit 163 Phase-locked circuit 200 Electronic equipment 300 Electronic equipment 400 Electronic equipment 500 indoor unit 600 outdoor unit 610 Compressor Devices 620 Fan Device 630 Oscillator 640 Oscillator 650 Oscillator

Claims

1. an oscillator circuit for generating an operating clock; a receiving circuit that receives a communication signal synchronized with a high-precision clock from an upstream device that operates on a high-precision clock having a frequency precision higher than that of the operating clock; a measurement circuit that measures a pulse width that is a width of a pulse included in the communication signal based on the operation clock; a memory that stores the reference value of the pulse width; a correction circuit that corrects the frequency of the operating clock based on a result of comparing the pulse width measured by the measurement circuit with the reference value; An electronic device having:

2. the oscillator circuit has a trimming circuit that changes the frequency of the operating clock based on an input voltage; the correction circuit corrects the frequency of the operating clock by inputting a voltage based on the difference between the measured value and the reference value to the trimming circuit. The electronic device of claim 1 .

3. The oscillator circuit comprises: a reference clock generation circuit that generates a reference clock having a frequency different from that of the operating clock; a phase locked loop circuit that generates the operating clock by dividing or multiplying the reference clock; and the correction circuit corrects the frequency of the operating clock by changing an internal parameter of the phase locked loop based on a result of comparing the measured value with the reference value; The electronic device of claim 1 .

4. The oscillator circuit comprises: a trimming circuit that changes the frequency of the operating clock based on an input voltage; a reference clock generation circuit that generates a reference clock having a frequency different from that of the operating clock; a phase locked loop circuit that generates the operating clock by dividing or multiplying the reference clock; and the correction circuit corrects the frequency of the operating clock by inputting a differential voltage based on the difference between the measured value and the reference value to the trimming circuit, and then corrects the frequency of the operating clock by changing an internal parameter of the phase locked loop based on a result of comparing the measured value obtained by measuring the pulse width of the new communication signal with the reference value. The electronic device of claim 1 .

5. the correction circuit corrects the frequency of the operation clock with a first resolution by inputting the differential voltage to the trimming circuit, and then corrects the frequency of the operation clock with a second resolution higher than the first resolution by changing an internal parameter of the phase locked loop; The electronic device according to claim 4 .

6. a data acquisition circuit for acquiring setting data of the reference value and storing the acquired reference value in the memory; 6. The electronic device according to claim 1.

7. the memory stores a plurality of reference value candidates; the correction circuit compares the measured value with the reference value selected from the plurality of reference value candidates based on the pulse width measured by the measurement circuit; 6. The electronic device according to claim 1.

8. a data acquisition circuit for acquiring instruction data including an instruction to correct the frequency of the operating clock; the correction circuit corrects the frequency of the operating clock in response to the reception of the instruction data by the receiving circuit; 6. The electronic device according to claim 1.

9. a temperature sensor for measuring an internal temperature of the electronic device; the correction circuit corrects the frequency of the operating clock when a deviation of the temperature measured by the temperature sensor from a reference temperature becomes equal to or greater than a threshold value.

6. The electronic device according to claim 1.

10. the memory further stores a cumulative time period during which the electronic device is in operation; the correction circuit corrects the frequency of the operating clock when the accumulation period reaches a predetermined period.

6. The electronic device according to claim 1.

11. a first electronic device that operates on a high-precision clock with a first frequency precision; a second electronic device that generates an operating clock having a second frequency accuracy lower than the first frequency accuracy; and The second electronic device is an oscillator circuit for generating an operating clock; a receiving circuit for receiving a communication signal synchronized with the high-precision clock from the first electronic device; a measurement circuit that measures a pulse width that is a width of a pulse included in the communication signal based on the operation clock; a memory that stores the reference value of the pulse width included in the communication signal; a correction circuit that corrects the frequency of the operating clock based on a result of comparing the pulse width measured by the measurement circuit with the reference value; An electronic device having:

12. a first electronic device and a second electronic device capable of communicating with the first electronic device; the first electronic device has a first electronic device that operates on a high-precision clock with a first frequency precision; the second electronic device has a second electronic device that generates an operating clock with a second frequency accuracy lower than the first frequency accuracy, The second electronic device is an oscillator circuit for generating an operating clock; a receiving circuit for receiving a communication signal synchronized with the high-precision clock from the first electronic device; a measurement circuit that measures a pulse width that is a width of a pulse included in the communication signal based on the operation clock; a memory that stores the reference value of the pulse width included in the communication signal; a correction circuit that corrects the frequency of the operating clock based on a result of comparing the pulse width measured by the measurement circuit with the reference value; An electronic device system having:

13. An air conditioning system comprising an indoor unit and an outdoor unit, one of the indoor unit and the outdoor unit has a first electronic device that operates on a high-precision clock with a first frequency precision; the other of the indoor unit and the outdoor unit has a second electronic device that generates an operation clock having a second frequency accuracy lower than the first frequency accuracy, The second electronic device is an oscillator circuit for generating an operating clock; a receiving circuit for receiving a communication signal synchronized with the high-precision clock from an apparatus having the first electronic device; a measurement circuit that measures a pulse width that is a width of a pulse included in the communication signal based on the operation clock; a memory that stores the reference value of the pulse width included in the communication signal; a correction circuit that corrects the frequency of the operating clock based on a result of comparing the pulse width measured by the measurement circuit with the reference value; An air conditioning system having:

14. An air conditioner capable of communicating with a communication device provided with a first electronic device that operates on a high-precision clock with a first frequency precision, the air conditioner has a second electronic device that generates an operating clock with a second frequency accuracy lower than the first frequency accuracy, The second electronic device is an oscillator circuit for generating an operating clock; a receiving circuit for receiving a communication signal synchronized with the high-precision clock from the communication device; a measurement circuit that measures a pulse width that is a width of a pulse included in the communication signal based on the operation clock; a memory that stores the reference value of the pulse width included in the communication signal; a correction circuit that corrects the frequency of the operating clock based on a result of comparing the pulse width measured by the measurement circuit with the reference value; An air conditioning device having:

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