JP2012251946A - Sensor module - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an easy-to-use sensor module which reduces time required for measurement to be started by shortening a warm-up period without increasing the number of components.SOLUTION: A sensor module 10 includes a physical quantity sensor 20 which detects a predetermined physical quantity and outputs the same as a detection signal; and a heating component 30 which generates heat when used. The heating component has a switching control section 46 which switches a plurality of operation modes. The switching control section, by switching between a normal operation mode to make the physical quantity sensor detect the physical quantity as well as output output data on the basis of the detection signal and a warm-up mode which changes a temperature of the physical quantity sensor to a target temperature, controls the warm-up mode to be executed before the normal operation mode when a predetermined condition is satisfied with a saturation temperature in the normal operation mode as the target temperature.

Description

  The present invention relates to a sensor module and the like.

  In recent years, sensor modules in which a physical quantity sensor that detects a predetermined physical quantity (for example, pressure, acceleration, and the like) and an arithmetic processing unit that performs arithmetic processing on a detection signal have been integrated. In the sensor module, a part other than the physical quantity sensor (for example, an arithmetic processing unit or the like) can be a heat source for increasing the temperature of the physical quantity sensor.

  The physical quantity sensor is easily affected by a change in temperature. For example, when the sensor module is activated, accurate measurement cannot be performed immediately. In general, a sensor module has a measurement waiting time (warm-up time) until the temperature becomes stable after activation. The shorter the warm-up time, the quicker the measurement can be started after startup, so it can be said that the sensor module is easy to use.

  For example, Patent Document 1 is an example of a pressure measuring device, but discloses an invention that reduces the influence of the operating environment temperature and shortens the warm-up time.

JP-A-8-178775

  However, in the method of Patent Document 1, it is necessary to symmetrically mount many components such as an F / V converter in addition to the pressure sensor on the sensor module. As a result, it becomes difficult to meet the demands for downsizing the sensor module and reducing the cost.

  On the other hand, if the physical quantity sensor is arranged away from the influence of heat from the heat source, the warm-up time may be shortened. However, with the downsizing of the sensor module, it has become difficult to separate the physical quantity sensor from a heat source such as an arithmetic processing unit.

  The present invention has been made in view of such problems. According to some aspects of the present invention, it is possible to provide an easy-to-use sensor module that shortens the warm-up time and increases the time to start measurement without increasing the number of parts.

(1) The present invention is a sensor module including a physical quantity sensor that detects a predetermined physical quantity and outputs it as a detection signal, and a heat generating component that generates heat when used, and the heat generating component includes a plurality of heat generating components. A switching control unit that switches an operation mode, wherein the switching control unit causes the physical quantity sensor to detect the predetermined physical quantity and outputs output data based on the detection signal; and targets the temperature of the physical quantity sensor Switching between a warm-up mode for changing to a temperature, and when a given condition is satisfied, control is performed so that the warm-up mode is executed before the normal operation mode, and saturation in the normal operation mode is performed. Let temperature be the target temperature.

(2) In this sensor module, the switching control unit may set the given condition as being at the time of activation.

  According to these inventions, for example, when a predetermined condition is satisfied before the normal operation mode in which data is output based on the detected value or the like, the temperature of the physical quantity sensor is changed to the target temperature. Run the mode. At this time, the time required for warm-up can be shortened without increasing the number of parts. For this reason, a sensor module that is easy to use is realized by shortening the time to start measurement.

  Here, the target temperature is a saturation temperature in the normal operation mode. The saturation temperature refers to a stable temperature in a saturated state that is reached when a sensor module or a subsequent circuit (for example, MCU) operates normally. Since the warm-up mode is an operation mode different from the normal operation, the effect of increasing the temperature is high. Moreover, since the target temperature is the saturation temperature, the effect of stabilizing the temperature is high.

  At this time, for example, the given condition for executing the warm-up mode may be a startup time. Further, for example, the given condition may be that the temperature of the physical quantity sensor is lowered from the saturation temperature by a predetermined temperature. Since the warm-up mode is performed only when necessary, a predetermined physical quantity can be detected efficiently.

  In these inventions, the temperature of the physical quantity sensor is stabilized at the saturation temperature in the normal operation mode by controlling the heat-generating component as a heat source. At this time, there is no increase in parts as in the invention of Patent Document 1. The predetermined physical quantity is, for example, pressure, acceleration, angular velocity, speed, etc., but is not limited thereto.

(3) In this sensor module, the switching control unit is a clock supplied to the heat-generating component, and is a normal operation clock used in the normal operation mode and a warm-up used in the warm-up mode. And the first highest frequency including the normal operation clock may be used as the frequency of the warm-up clock.

  According to the present invention, in the warm-up mode, the highest first frequency including the normal operation mode is used as the frequency of the clock supplied to the heat generating component. Therefore, the temperature of the physical quantity sensor can be quickly raised. A relatively simple method of selecting the clock frequency realizes a sensor module that shortens the warm-up time and has a short waiting time until the start of measurement.

(4) In this sensor module, in the warm-up mode, the switching control unit sets the frequency of the warm-up clock until the temperature of the physical quantity sensor reaches a first temperature exceeding the target temperature. Then, the second frequency may be lower than the first frequency.

  According to the present invention, in order to converge to the saturation temperature in the warm-up mode, the frequency of the clock supplied to the heat-generating component is initially set to the highest first frequency, but has become the first temperature exceeding the target temperature. If so, switch to a lower second frequency. Since the two clock frequencies are switched and used according to the situation, it is easy to converge to the saturation temperature in the warm-up mode.

(5) In this sensor module, in the warm-up mode, the switching control unit is configured when the frequency of the warm-up clock is the second frequency, and the temperature of the physical quantity sensor is lower than the target temperature. After reaching the second temperature, the frequency of the warm-up clock may be a third frequency that is lower than the first frequency and higher than the second frequency.

  According to the present invention, in order to converge to the saturation temperature in the warm-up mode, the highest first frequency and the second lower frequency are switched and used as the frequency of the clock supplied to the heat generating component. And when it is the 2nd frequency, after it becomes 2nd temperature lower than target temperature, it switches to the 3rd frequency further. Here, the third frequency is lower than the first frequency but higher than the second frequency. Since the three clock frequencies are switched and used according to the situation, it is easy to converge to the saturation temperature in the warm-up mode.

(6) In the sensor module, in the warm-up mode, the switching control unit performs control so that the temperature of the physical quantity sensor does not exceed the target temperature based on temperature information, and the temperature of the physical quantity sensor is As the temperature approaches the target temperature, the frequency of the warm-up clock may be lowered.

(7) In the sensor module, the switching control unit may determine at least one of a frequency and a period of the warm-up clock based on an elapsed time from the start of the warm-up mode.

  According to these inventions, in order to converge to the saturation temperature in the warm-up mode, first, the first frequency that is the highest as the frequency of the clock supplied to the heat-generating component is used, and the frequency gradually increases as the temperature approaches the saturation temperature. Switch to a lower clock. At this time, it becomes possible to approach the saturation temperature stepwise and accurately.

  At this time, during the warm-up mode, the temperature of the physical quantity sensor is equal to or lower than the saturation temperature that is the target temperature. The rising temperature can be predicted based on the elapsed time from the start of the warm-up mode. Therefore, the clock may be gradually switched to a lower frequency based on this elapsed time. The timing for switching from the warm-up mode to the normal operation may also be determined based on the elapsed time from the start of the warm-up mode. The operation switching control based on the elapsed time makes it possible to simplify the control method and reduce the circuit scale.

  The temperature information may be obtained from a physical quantity sensor, or may be information obtained from a separate temperature sensor included in the sensor module. The sensor module is integrated so that at least heat is transmitted. Therefore, frequency adjustment or the like can be performed based on the temperature in real time based on any temperature information.

(8) In this sensor module, the physical quantity sensor may detect at least a pressure as the predetermined physical quantity.

  According to the present invention, the physical quantity sensor may be a pressure sensor. Since the pressure information detected by the pressure sensor is easily affected by temperature fluctuations, the temperature needs to be stable during the measurement. The sensor module of the present invention that can shorten the warm-up time makes it possible to measure an accurate value quickly after activation.

The block diagram of the sensor module in 1st Embodiment. FIG. 2A is a block diagram showing connection of the sensor module in the first embodiment. FIG. 2B is a cross-sectional view of a physical structure example of the sensor module. FIG. 3A to FIG. 3B are flowcharts of the first embodiment. FIG. 4A is a relationship diagram of the heat generation amount in the normal operation mode of the first embodiment. FIG. 4B is a diagram illustrating changes in temperature and detected pressure according to the first embodiment. FIG. 5A is a diagram illustrating an example of a temperature change only in a normal operation process. FIG. 5B is a diagram illustrating the start-up time when there is a warm-up process. The figure showing the execution conditions of a warm-up process. FIG. 7A is a diagram showing a change with time in temperature and pressure (first example). FIG. 7B is a diagram (first example) illustrating an example of specific control of the MCU and the pressure sensor. FIG. 8A is a diagram (second example) showing temporal changes in temperature and pressure. FIG. 8B is a diagram showing a specific example of control of the MCU and the pressure sensor (second example). FIG. 9A is a diagram showing a change over time in temperature and pressure (third example). FIG. 9B is a diagram showing a specific example of control of the MCU and the pressure sensor (third example). FIG. 10A is a diagram showing a change over time in temperature and pressure (fourth example). FIG. 10B is a diagram illustrating a specific control example of the MCU and the pressure sensor (fourth example). FIG. 11A to FIG. 11C are diagrams showing an example of arrangement of parts of the sensor module. FIG. 12A to FIG. 12C are diagrams showing another example of the arrangement of parts of the sensor module. The block diagram of the sensor module in 2nd Embodiment.

  Embodiments of the present invention will be described below with reference to the drawings. In the description of the second embodiment, the same elements as those in the first embodiment are denoted by the same reference numerals, and the description thereof is omitted.

1. First embodiment 1.1. Configuration of Sensor Module A first embodiment of the present invention will be described with reference to FIGS. 1 to 12C. FIG. 1 is a block diagram of a sensor module 10 of the present embodiment.

  The sensor module 10 of this embodiment includes a pressure sensor 20 and an MCU 30. The pressure sensor 20 is a physical quantity sensor that detects pressure. Further, the MCU 30 has a property as a heat generating component that generates heat during operation and affects the temperature of the pressure sensor 20. The sensor module 10 of this embodiment additionally includes a TCXO (temperature compensated crystal oscillator) 50. The TCXO 50 is a temperature compensated crystal oscillator and supplies a temperature compensated clock signal 150 to the pressure sensor 20.

  Here, the sensor module 10 is required to be reduced in size while reducing the circuit scale. On the other hand, the MCU 30 requires a plurality of clock signals, and there is a demand to reduce power consumption by dynamically stopping and operating these clock signals.

  For example, there may be a configuration in which a plurality of TCXOs are prepared as the clock source of the MCU 30. However, it is not realistic because it goes against the demand for downsizing the sensor module 10. In order to stop and operate a dynamic clock signal, the MCU 30 itself preferably includes an oscillation circuit. Therefore, the sensor module 10 of this embodiment includes only one TCXO 50 that supplies a clock signal only to the pressure sensor 20.

  The pressure sensor 20 includes a pressure detection unit 22 that detects pressure, a temperature detection unit 24 that detects temperature, and a logic unit 26 that controls input and output of data between these detection units and the MCU 30.

  The pressure detection unit 22 receives an instruction from the outside of the sensor module 10 as the control signal 121 via the logic unit 26 and operates according to the content of the control signal 121. During operation, for example, pressure data 122 detected in real time is output as sensor data 126 via the logic unit 26.

  Here, the pressure detected in the present embodiment is the atmospheric pressure around the pressure sensor 20, but is not limited thereto. The pressure data 122 may be output at predetermined time intervals, or the logic unit 26 may average or select the pressure data 122 and output it as sensor data 126.

  The temperature detection unit 24 receives an instruction from the outside of the sensor module 10 as the control signal 123 via the logic unit 26 and operates according to the content of the control signal 123. During operation, for example, temperature data 124 detected in real time is output as sensor data 126 via the logic unit 26.

  Here, the temperature detected in the present embodiment is the temperature around the pressure sensor 20, but is not limited thereto. For example, the surface temperature of the pressure sensor 20 may be used. The temperature data 124 may be output at a predetermined time interval, or the logic unit 26 may average or select the temperature data 124 and output it as sensor data 126.

  In the present embodiment, the sensor module 10 is hermetically sealed, and the temperature of the pressure sensor 20 is the same as the temperature of other parts inside the sensor module 10. In the following description, the temperature of the pressure sensor 20 may be simply expressed as temperature.

  As described above, the logic unit 26 controls data input / output between the pressure detection unit 22, the temperature detection unit 24, and the MCU 30. A control signal 130 based on an instruction from the outside of the sensor module 10 is received from the MCU 30 and output to at least one of the pressure detection unit 22 and the temperature detection unit 24. Further, the pressure data 122 and the temperature data 124 are output to the MCU 30 as sensor data 126. The logic unit 26 may add, for example, time stamp information to the sensor data 126 and output the data for data management.

  The communication method between the pressure sensor 20 and the MCU 30 may be parallel transfer or serial transfer. In the case of serial transfer, for example, a communication method such as I2C (Inter-Integrated Circuit) or SPI (Serial Peripheral Interface) may be used.

  The MCU 30 switches the operation mode of the sensor module 10, the communication control unit 44 that controls communication with the outside of the sensor module 10, and the operation mode of the sensor module 10, and generates a clock signal having a frequency according to the operation mode. A clock generation switching unit 46 for generating and supplying and a CR oscillation circuit 47 are included.

  The MCU 30 temporarily stores the sensor data 126 and outputs it as sensor data 132. The pressure data 134 and the pressure information temporarily store the temperature information 135 obtained by calculating the sensor data 132 related to pressure and temperature, respectively. An information storage unit 38, a temperature information storage unit 40, and a communication data storage unit 42 for temporarily storing communication data with the outside of the sensor module 10 may be included.

  Further, the MCU 30 includes a sensor operation setting unit 36 that converts an instruction from the outside of the sensor module 10 into a control signal 130 of the pressure sensor 20 and outputs the control signal 130, and an activation time measurement unit 48 that measures activation time when the power is turned on. You may go out.

  An appropriate clock signal is supplied to each of these functional blocks from the clock generation switching unit 46, but is not shown in FIG. In addition, all of these functional blocks are not essential components and can be omitted as appropriate.

  The MCU 30 stores the sensor data 126 from the pressure sensor 20 in the sensor data storage unit 32. Then, sensor data 132 is read from the sensor data storage unit 32 at a predetermined timing, and the arithmetic processing unit 34 performs arithmetic processing.

  In the present embodiment, the sensor data 126 is so-called raw data detected by the pressure sensor 20. For example, unprocessed data in which pressure and temperature are expressed as relative values with respect to a reference value built in the pressure sensor. And it is converted into a format as output data of the sensor module 10 by the arithmetic processing performed by the arithmetic processing unit 34. For example, the arithmetic processing unit 34 outputs pressure information 134 in units of “Pa” and temperature information 135 in units of “° C.” from the sensor data 132 that is raw data.

  The pressure information 134 and the temperature information 135 are temporarily stored in the pressure information storage unit 38 and the temperature information storage unit 40, respectively, and then read out as the pressure information 136 and the temperature information 140 and temporarily stored in the communication data storage unit 42. . At this time, conversion into a format suitable for communication is performed. Then, it is output as MCU output data 100 at a predetermined transfer rate based on the communication timing signal 144 from the communication control unit 44.

  The communication data storage unit 42 temporarily stores the MCU input data 102. The MCU input data 102 is an instruction to the pressure sensor 20 from the outside of the sensor module 10. The sensor operation setting unit 36 receives the MCU input data 137 temporarily stored from the communication data storage unit 42, converts it into a control signal 130 for the pressure sensor 20, and outputs it.

  Here, the communication method between the sensor module 10 and the outside may be parallel transfer or serial transfer. In the case of serial transfer, for example, I2C or SPI may be used, or UART (Universal Asynchronous Receiver Transmitter) or USB (Universal Serial Bus) may be used.

  Then, the CR oscillation circuit 47 supplies the original oscillation clock signal 147 to the activation time measurement unit 48 and the clock generation switching unit 46. The CR oscillation circuit 47 has a function as an oscillation circuit unit in the MCU 30.

  The activation time measuring unit 48 measures the activation time based on the original oscillation clock signal 147 and outputs a timing signal 148 to the clock generation switching unit 46. The clock generation switching unit 46 switches the operation mode based on the timing signal 148 and the like.

  The clock generation switching unit 46 generates a necessary clock signal corresponding to the operation mode from the original clock signal 147 and supplies it to other functional blocks. The generation of the clock signal may be performed by frequency division, for example. The clock generation switching unit 46 has a function as a clock generation circuit and a function as an operation mode switching control unit.

  The clock generation switching unit 46 outputs a clock signal 146 that operates the counter of the communication control unit 44. The communication control unit 44 generates a communication timing signal 144 that determines the input / output timing of communication data based on the counter value.

  The communication control unit 44 and the clock generation switching unit 46 receive the temperature information 140 from the temperature information storage unit 40, and perform a counter cycle for determining the operation mode switching timing (that is, the period of each operation mode) and the communication timing. You may adjust.

1.2. Connection of Sensor Module FIG. 2A is a diagram illustrating a connection between the sensor module 10 and a host MCU (hereinafter referred to as a host) 14 that communicates with the sensor module 10 in the electronic device 1. Note that the same elements as those in FIG.

  As shown in FIG. 2A, the sensor module 10 of this embodiment is connected to the host 14 via the format conversion module 12. The format conversion module 12 converts the format of communication data during communication. For example, when the host 14 is a part of a PC (personal computer), the output data 104 and the input data 106 of the format conversion module 12 may conform to a USB communication system. At this time, even if the communication method of the sensor module 10 itself is not USB, communication with the host 14 can be performed.

  Through the format conversion module 12, even if the sensor module 10 conforms to one communication method, the types of hosts 14 that can communicate with the sensor module 10 can be increased. When the sensor module 10 and the host 14 can be directly connected, the format conversion module 12 may be omitted.

  FIG. 2B is a diagram illustrating a structure example of the sensor module 10 and the format conversion module 12 of the present embodiment. The module group 2 in FIG. 2B corresponds to the module group 2 illustrated by the dotted line in FIG. In addition, the same code | symbol is attached | subjected to the same element as FIGS. 1-2 (A), and description is abbreviate | omitted. Note that illustrations of a cover for covering the sensor module 10 and the format conversion module 12 are omitted.

  The module group 2 in FIG. 2B is configured by connecting the sensor module 10 and the format conversion module 12 with a connector 64. FIG. 2B shows a cross-sectional view of the module group 2. The format conversion module 12 arranges a format conversion circuit 13 that converts communication data and a host connection connector 66 that is, for example, a USB connector on a substrate 62 as shown in FIG. ing.

  In the sensor module 10, the pressure sensor 20 and the MCU 30 are arranged on both surfaces of the substrate 60, respectively. Here, it is difficult to dispose the pressure sensor 20 and the MCU 30 sufficiently apart from each other in order to meet the recent demand for miniaturization. However, since the MCU 30 operates as a heat source (see the arrow in FIG. 2B), if the pressure sensor 20 is disposed nearby, the temperature will be increased. When the temperature rises (when it fluctuates), an error due to temperature fluctuation occurs in the detection signal (sensor data) from the pressure sensor 20, so that it is difficult to detect an accurate value.

  Here, even in the structure as shown in FIG. 2B, it is known that the temperature of the pressure sensor 20 is saturated when the MCU 30 continues to operate for a certain time. When the pressure is detected in a state where the temperature is saturated, it is possible to avoid the occurrence of an error due to temperature fluctuation.

  Therefore, it is considered to saturate the temperature at an early stage by devising the operation control of the MCU 30 as a heat source so as to suppress the temperature fluctuation of the pressure sensor 20. Below, after explaining the flow of the operation mode of the sensor module 10, the operation control of the MCU 30 in this embodiment will be described in detail.

1.3. Flow of Operation Mode FIGS. 3A to 3B are flowcharts of the operation mode of the sensor module in this embodiment. The pressure sensor and MCU included in the sensor module perform a predetermined operation according to the operation mode or enter a standby state that is a standby state. In addition, the sensor module has a control unit (switching control unit) that switches the operation mode inside or outside, but in this embodiment, the clock generation switching unit (see FIG. 1) has the function.

  Here, the sensor module generally warms up when it is activated. During the warm-up period, the sensor module changes from a low temperature state to a state where the temperature is stable and an accurate pressure can be detected (a state where the temperature is saturated). And normal operation is performed after warm-up.

  FIG. 3A is a flowchart of the operation mode of the sensor module in the present embodiment. First, the necessity of a warm-up process is determined (S10). If necessary (S10Y), a warm-up process is performed (S12), followed by normal operation (S20). If it is determined that the warm-up process is unnecessary (S10N), the process immediately moves to the normal operation process (S20). The condition (S10) for executing the warm-up process may be that the temperature of the pressure sensor is lower than the saturation temperature, or may be at the time of startup.

  In the sensor module according to the present embodiment, if there is no end instruction (S30N), the process returns to S10 and the series of processes is repeated. For example, if there is an end instruction from the user or an end instruction accompanying the elapse of the set time, the sensor module ends the operation (S30Y).

  Here, the normal operation step (S20) is a step corresponding to an operation such as a sensing operation or outputting of data in a predetermined format that the sensor module performs during normal operation.

  As shown in FIG. 3B, the normal operation step (S20) includes steps corresponding to three operation modes. Specifically, a pressure sensor operation step (S22), an MCU operation step (S24), and a standby step (S26). In the present embodiment, these steps are performed in order, but the standby step (S26) may be omitted.

  In the pressure sensor operation step (S22), the clock generation switching unit performs pressure sensor operation control and causes the pressure sensor to perform a sensing operation. At this time, the clock generation switching unit may operate only the sensor data storage unit (see FIG. 1) that receives the sensor data in the MCU to suppress power consumption.

  In the MCU operation step (S24), the clock generation switching unit performs MCU operation control and causes the MCU to perform sensor data calculation processing. At this time, the clock generation switching unit may place the pressure sensor in a standby state.

  In the standby step (S26), the clock generation switching unit may perform standby control and operate only the MCU communication function. At this time, the clock generation switching unit may place the pressure sensor in a standby state. The clock generation switching unit may operate the MCU communication function also in the pressure sensor operation step (S22) and the MCU operation step (S24).

  As described above, the operation mode of the sensor module is changed, and the operation states of the pressure sensor and the MCU are also changed. On the premise of this change, it is necessary to control the operation of the MCU so as to make the warm-up period as short as possible.

1.4. Saturation Temperature An example of the saturation temperature of the sensor module in the present embodiment will be described with reference to FIGS. 4 (A) to 4 (B).

  FIG. 4A shows a comparison between the heat generation amount Q1 in the pressure sensor operation process and the heat generation amount Q2 in the MCU operation process in the present embodiment. In this embodiment, in the MCU operation process, the frequency of the clock signal of the MCU is selected so that data can be transmitted to the host at a necessary transfer rate. The period of the MCU operation process is also adjusted so that the heat generation amount Q2 is the same as the heat generation amount Q1.

  FIG. 4B shows the relationship between temperature and detected pressure. In this example, the calorific value Q2 is set to be the same as the calorific value Q1, so that the temperature is stable and the pressure is not affected by temperature fluctuations. At this time, the constant temperature in FIG. 4B can be set as the saturation temperature.

  This saturation temperature is set as the target temperature in the warm-up mode. By selecting the saturation temperature as the target temperature, temperature fluctuation can be suppressed and stabilized even when switching from the warm-up mode to the normal operation mode.

  It is known that even when the calorific value Q2 is different from the calorific value Q1, it eventually saturates to a certain temperature due to the relationship between the heat generated from the pressure sensor and MCU and the heat radiation of the sensor module. However, since it takes time until the temperature stabilizes at this time, the temperature reached when a sufficient time (for example, several minutes) has elapsed may be set as the saturation temperature. The saturation temperature may be obtained by calculation or may be determined based on data obtained by actual measurement in advance.

  Here, it is considered that the temperature of the standby process varies depending on the period. It is considered that the temperature is maintained when the period of the standby process is short. And if it is long, there is a possibility of a drop from the saturation temperature, so that it is necessary to perform the warm-up mode as will be described later.

1.5. Warm-up Conditions Here, an example of a case where warm-up is necessary (see S10Y in FIG. 3A) will be described with reference to FIGS.

FIG. 5A to FIG. 5B are diagrams for explaining the effect of the warm-up process at the time of startup. FIG. 5A is a comparative example, and shows a temperature change when only the normal operation process is performed from the start-up. In this case, when the temperature reaches the saturation temperature T _s at the temperature rising period T _A0 as shown in FIG. 5 (A), the then to a temperature stabilization period T _B in which the temperature hardly changes. However, since the temperature rise period T _{A0 in} which the temperature change affects the detected pressure value continues for a long time, accurate measurement cannot be performed immediately after activation.

Therefore, in the sensor module of the present embodiment, a warm-up process is performed in which operation is performed so that a large amount of current flows through the MCU that is a heat source at the time of startup or the like. Then, as in FIG. 5 (B), is shortened temperature rising period T _A1 is, moves to the temperature stabilization period T _B early. Therefore, an easy-to-use sensor module with a quick start-up time can be realized.

Further, even at times other than the start-up, the temperature may decrease when the standby process in the normal operation process continues for a long time. Also in this case, it is preferable to return the temperature of the sensor module to the saturation temperature T _s early. In such a case, in this embodiment, the warm-up process is executed after the standby process as shown in FIG. Thereby, the sensor module which can detect a pressure stably is realizable.

  Here, the warm-up process is not necessary when the temperature is not lowered due to the standby process except at the time of startup. For this reason, in the present embodiment, whether or not to perform the warm-up process can be determined according to the situation (see S10 in FIG. 3A).

  In addition, you may judge the presence or absence of the temperature fall by a standby process by the period of a standby process. At this time, when the warm-up process is performed, the period during which the temperature is increased by the warm-up process may be adjusted based on the length of the standby process. For example, when the standby process is long (for example, several seconds), it is determined that the temperature is greatly reduced, so the period of the warm-up process may be lengthened (for example, 500 ms).

1.6. Specific example of control of clock generation switching unit 1.6.1. First Example FIG. 7A is obtained by adding data (pressure) detected by a pressure sensor to the graph of temperature change at the time of activation in FIG. 5B. As shown in FIG. 7A, when the temperature is stabilized, the data detected by the pressure sensor is also stabilized. Normal operation including sensing operation is performed after t _b when the temperature is stabilized.

  FIG. 7B is a diagram illustrating specific control for the MCU and the pressure sensor in each step performed by the clock generation switching unit. For the MCU, control is performed to switch the clock. Here, it is assumed that different clocks are used in the pressure sensor operation process, the MCU operation process, the standby process, and the warm-up process.

  Here, for convenience of description, clocks used in the pressure sensor operation process, the MCU operation process, and the standby process are referred to as a first clock, a second clock, and a third clock, respectively. A clock signal used in the warm-up process is called a fourth clock. At this time, the first to third clocks are divided into normal operation clocks used in the normal operation mode. The fourth clock is a warm-up clock.

  As for the pressure sensor, the clock signal is always supplied from the TCXO (see FIG. 1), and the clock generation switching unit controls whether or not to enter the standby state. The standby state means a state other than the sensing operation such as a stopped state.

In this embodiment, the clock generation switching unit generates four clocks based on the original oscillation clock signal from the CR oscillation circuit. The four frequencies F ₀ , F ₁ , F ₂ , and F ₃ assigned to each clock are assumed to have a relationship of F ₀ ≦ F ₁ <F ₂ <F ₃ .

In the first embodiment, the period of the warm-up process corresponds to the temperature increase period. And it is preferable that the period of a warm-up process is as short as possible. Therefore, the fourth clock of the warm-up process, assign the highest frequency (first frequency) F _3. At this time, since the amount of heat generated by the MCU increases, the period of the warm-up process can be shortened.

In the first example, the frequency of the fourth clock remains unchanged at F _3. Therefore, the control is simple, and the circuit scale of the clock generation switching unit can be reduced. Note that the pressure sensor is in a standby state. Although it may be stopped, a dummy operation may be performed in order to further increase the amount of heat generated in the warm-up process.

Of the normal operation process, a high frequency clock signal is preferably used in the MCU operation process in which the processing capacity needs to be increased. Therefore, the second clock MCU operating process, assigns a frequency _{F 2.} At this time, the pressure sensor is in a standby state.

Of the normal operation steps, in the standby step, the clock signal having the lowest frequency is preferably used in order to reduce power consumption. Therefore, the frequency F ₀ is assigned to the third clock in the standby process. The pressure sensor is also in a standby state, and it is preferable to suppress power consumption.

Among normal operation process, the first clock of the pressure sensor operation step, assigning a frequency F _1. This is to reduce power consumption while executing processing for storing sensor data. At this time, the pressure sensor performs a sensing operation.

  As described above, the clock generation switching unit can realize the effect of speeding up the activation time and the like of the sensor module of the first embodiment by performing the control as shown in FIG. 7B. In this embodiment, a different clock is generated and switched for each operation process. However, only one clock is supplied to the MCU, and the frequency may be changed for each operation process. .

1.6.2. Second Example FIG. 8A is a diagram illustrating changes in temperature and pressure at start-up when the control of the second example is performed. In addition, the same code | symbol is attached | subjected to the same element as FIG. 7 (A)-FIG.7 (B), and description is abbreviate | omitted. Normal operation also comprising sensing operation in the example of FIG. 8 (A) is carried out after t _b the temperature stabilizes.

Unlike the example of FIG. 7A (first example), in FIG. 8A, a first temperature T ₁ equal to or higher than the saturation temperature T _s is reached during the warm-up process (time t _a ), and thereafter It has converged to the saturation temperature T _s (time t _b ). Depending on the combination of the highest frequency (first frequency) and the period of the warm-up process, the saturation temperature T _s that is the target temperature may be exceeded during the warm-up process as shown in FIG. 8A. In addition, if the temperature is rapidly increased so as to exceed the saturation temperature T _s during the warm-up process, the period of the warm-up process can be further shortened.

  In the second example, two clock frequencies (first frequency and second frequency) are switched and used in the warm-up process. Thereby, in the warm-up process, it becomes easier to converge to the saturation temperature than in the first example.

In this embodiment, the clock generation switching unit generates a normal operation clock and a warm-up clock based on the original oscillation clock signal from the CR oscillation circuit. Here, the five frequencies F ₀ , F ₁ , F ₂ , F ₃ , and F ₄ assigned to these clocks have a relationship of F ₀ ≦ F ₁ <F ₂ <F ₄ and F ₃ <F ₄ . Shall.

FIG. 8B is a diagram showing specific control. In the warm-up process, the following control is performed. The warm-up clock is first assigned the highest F ₄ as the first frequency. Then, after reaching the first temperature _{T 1} (time _{t a} the following figures 8 (A)), _{F 3} is assigned as the second frequency. Since there is a relationship of F ₃ <F ₄ , the temperature falls from the first temperature T ₁ and converges to the saturation temperature T _s .

The normal operation process is the same as in the first example. That, is used the clock high frequency F ₂ in MCU operation step For greater processing power, the clock of a lower frequency F ₀ in the standby step it is desired to suppress power consumption is used, the frequencies F ₁ is a pressure sensor operating step A clock is used. Further, the pressure sensor is the same as that in the first example, and thus the description thereof is omitted.

In this way, the clock generation switching unit can make the startup time of the sensor module faster by performing the control as shown in FIG. 8B. Note that first temperature T ₁ may be determined based on the saturation temperature T _s. For example, predetermined temperature than the saturation temperature T _s (for example, several ° C.) may be as high temperatures, a constant ratio to the saturation temperature T _s (e.g., 110%) may be a temperature obtained by multiplying a.

1.6.3. Third Example FIG. 9A is a diagram illustrating changes in temperature and pressure at start-up when the control of the third example is performed. In addition, the same code | symbol is attached | subjected to the same element as FIG. 7 (A)-FIG. 8 (B), and description is abbreviate | omitted. In the example of FIG. 9A, the normal operation including the sensing operation is performed after t _b when the temperature is stabilized.

In addition to the change in the example of FIG. 8A (second example), in FIG. 9A, a second temperature T _{2 lower} than the saturation temperature T _s is reached during the warm-up process (time t _a1 ), After that, it converges to the saturation temperature T _s (time t _b ). The period of the warm-up process can be further shortened by performing a rapid temperature rise exceeding the saturation temperature T _s during the warm-up process and then a temperature decrease below the saturation temperature T _s .

  In the third example, three clock frequencies (first frequency, second frequency, and third frequency) are switched and used in the warm-up process. Thereby, in the warm-up process, it becomes easier to converge to the saturation temperature than in the second example.

In this embodiment, the clock generation switching unit generates a normal operation clock and a warm-up clock based on the original oscillation clock signal from the CR oscillation circuit. Here, the six frequencies F ₀ , F ₁ , F ₂ , F ₃ , F ₄ , F ₅ assigned to these clocks are F ₀ ≦ F ₁ <F ₂ <F ₅ and F ₃ <F ₄ < it is assumed that there is a relationship of F _5.

FIG. 9B is a diagram showing specific control. In the warm-up process, the following control is performed. The warm-up clock is first assigned the highest F ₅ as the first frequency. Then, after reaching the first temperature T ₁ (after time ta _{0 in} FIG. 9A), F ₃ is assigned as the second frequency. Since there is a relationship of F ₃ <F ₅ , the temperature falls from the first temperature T ₁ , and in this example, becomes a _second temperature T ₂ lower than the saturation temperature T _s (time t in FIG. 9A). _a1 ).

Thereafter, F ₄ is assigned as the third frequency. Since there is a relationship of F ₃ <F ₄ <F ₅ , the temperature rises from the second temperature T ₂ and converges to the saturation temperature T _s .

The normal operation process is the same as in the first example. That, is used the clock high frequency F ₂ in MCU operation step For greater processing power, the clock of a lower frequency F ₀ in the standby step it is desired to suppress power consumption is used, the frequencies F ₁ is a pressure sensor operating step A clock is used. Further, the pressure sensor is the same as that in the first example, and thus the description thereof is omitted.

As described above, the clock generation switching unit can make the startup time of the sensor module faster by performing the control as shown in FIG. 9B. The temperature T ₂ of the second may be determined based on the saturation temperature T _s. For example, predetermined temperature than the saturation temperature T _s (for example, several ° C.) may be used as the low temperature, a constant ratio to the saturation temperature T _s (e.g., 90%) may be a temperature obtained by multiplying a. Further, a third temperature, a fourth temperature,... May be determined, and frequencies corresponding to these temperatures may be set to further shorten the period of the warm-up process.

1.6.4. Fourth Example FIG. 10A is a diagram illustrating changes in temperature and pressure at start-up when the control of the fourth example is performed. In addition, the same code | symbol is attached | subjected to the same element as FIG. 7 (A)-FIG. 9 (B), and description is abbreviate | omitted. In the example of FIG. 10A, the normal operation including the sensing operation is performed after t _b when the temperature is stabilized.

As shown in FIG. 10A, in this example, control is performed so as not to exceed the saturation temperature T _s that is the target temperature. Since the temperature rises with time, temperature control can be performed based on the elapsed time. At this time, the timing for switching the frequency, an appropriate clock frequency, and the like can be easily obtained by, for example, simulation or calculation by MCU.

For example, first, the highest frequency F _n (corresponding to the first frequency) is assigned, and when the time t _a0 is reached, the frequency F _n−1 (<F _n ) is switched. Then, when the time t _a1 is reached, the frequency is switched to the frequency F _n−2 (<F _n−1 ). By such control, it is possible to converge to the saturation temperature T _s with a monotone increase.

FIG. 10B is a table showing this control. The frequencies F ₀ , F ₁ , F ₂ , F ₃ ,... F _n are prepared, and for three or more subscripts, the frequency is increased as it increases. In the warm-up process, at least two frequencies are switched. Thereby, it is possible to converge to the saturation temperature T _s by simple control based on the elapsed time. Here, n is a natural number and is 4 or more.

The normal operation process is the same as in the first example. That, is used the clock high frequency F ₂ in MCU operation step For greater processing power, the clock of a lower frequency F ₀ in the standby step it is desired to suppress power consumption is used, the frequencies F ₁ is a pressure sensor operating step A clock is used. Further, the pressure sensor is the same as that in the first example, and thus the description thereof is omitted.

1.7. About arrangement | positioning of the component of a sensor module In 1st Embodiment, it is not necessary to arrange | position the MCU used as a heat source, and a pressure sensor separately. This increases the degree of freedom of component placement in the sensor module and enables further miniaturization.

  In the warm-up process, it is more effective to shorten the startup time and the like when the MCU and the pressure sensor are arranged close to each other. Hereinafter, an example of the arrangement of components in the sensor module suitable for the first embodiment will be described with reference to FIGS. 11 (A) to 12 (C).

  FIG. 11A shows a state where the pressure sensor 20 and the TCXO 50 are disposed on the surface of the substrate 60. On the other hand, FIG. 11B shows a state in which a connector 64 for connecting the MCU 30 and a format conversion module or the like is disposed on the back surface of the substrate 60.

Here, FIG. 11C is a cross-sectional view taken along line xx of FIGS. 11A and 11B. The pressure sensor 20 and the MCU 30 are arranged so as to overlap each other by a width W _o with the substrate 60 interposed therebetween. For this reason, heat from the MCU 30 is easily transmitted to the pressure sensor 20, and there is an effect of shortening the temperature rise period in the warm-up process. For example, the effect is enhanced by mounting the pressure sensor 20 and the MCU 30 on COB (Chip On Board) having high heat conductivity. Furthermore, the effect can be further enhanced by making the substrate 60 thinner.

Here, the width W _o is a value larger than zero. In the example of FIG. 11 (C), the when the width of the pressure sensor 20 has a width of _W s, MCU 30 and _{W m,} is smaller than the width of the smaller one of _{W s} and _{W m.} That is, in the example of FIG. 11C, the pressure sensor 20 and the MCU 30 partially overlap. There are no particular restrictions on the overlapping direction.

  FIGS. 12A to 12C show another example of arrangement of parts. In addition, the same code | symbol is attached | subjected to the same element as FIG. 11 (A)-FIG.11 (C), and description is abbreviate | omitted.

In this example, as shown in FIGS. 12A to 12B, the MCU 30 and the pressure sensor 20 are arranged to overlap as much as possible. As shown in the cross-sectional view of FIG. 12C, in this example, the width W _o is equal to the width W _s of the pressure sensor. Therefore, the heat from the MCU 30 is more easily transmitted to the pressure sensor 20, and there is an effect of further shortening the temperature rise period in the warm-up process. Moreover, in the example of FIG. 12 (A)-FIG.12 (C), the way of heat transmission becomes uniform.

2. Second Embodiment A second embodiment of the present invention will be described with reference to FIG. In addition, the same code | symbol is attached | subjected to the same element as FIGS. 1-12C, and description is abbreviate | omitted.

  FIG. 13 is a block diagram of the sensor module 10A of the present embodiment. Unlike the sensor module of the first embodiment, an acceleration sensor 20A is included instead of a pressure sensor. In the present embodiment, acceleration information is obtained instead of pressure information. It also includes a temperature sensor 20B that detects the temperature for use in clock frequency selection in the warm-up process.

  However, even if the sensor portion changes in this way, the configuration of the MCU 30A and the control performed by the clock generation switching unit 46 are hardly changed. Therefore, a sensor module including various physical quantity sensors (acceleration sensor in the second embodiment) can be realized by the same control method as in the first embodiment.

3. Others The present invention is not limited to these examples, and the present invention includes configurations that are substantially the same as the configurations described in the embodiments (for example, configurations that have the same functions, methods, and results, or configurations that have the same purposes and effects). . In addition, the invention includes a configuration in which a non-essential part of the configuration described in the embodiment is replaced. In addition, the present invention includes a configuration that exhibits the same operational effects as the configuration described in the embodiment or a configuration that can achieve the same object. Further, the invention includes a configuration in which a known technique is added to the configuration described in the embodiment.

DESCRIPTION OF SYMBOLS 1 ... Electronic device, 2 ... Module group 10, 10A ... Sensor module, 12 ... Format conversion module, 13 ... Format conversion circuit, 14 ... Host MCU (host), 20 ... Pressure sensor, 20A ... Acceleration sensor, 20B ... Temperature Sensor, 22 ... Pressure detection unit, 24 ... Temperature detection unit, 26 ... Logic unit, 30, 30A ... MCU, 32 ... Sensor data storage unit, 34 ... Calculation processing unit, 36 ... Sensor operation setting unit, 38 ... Pressure information storage 38A ... Acceleration information storage unit 40 ... Temperature information storage unit 42 ... Communication data storage unit 44 ... Communication control unit 46 ... Clock generation switching unit 47 ... CR oscillation circuit 48 ... Start-up time measurement unit 50 ... TCXO, 60, 62 ... Board, 64 ... Connector, 66 ... Host connection connector, 100 ... MCU output data, 10 137 ... MCU input data 104 ... Output data 106 ... Input data 121 ... Control signal 122 ... Pressure data 123 ... Control signal 124 ... Temperature data 126,126A, 126B ... Sensor data 130,130A, 130B ... Control signal 132 ... Sensor data 134 ... Pressure information 134A ... Acceleration information 135 ... Temperature information 136 ... Pressure information 136A ... Acceleration information 140 ... Temperature information 144 ... Communication timing signal 146 ... Clock signal 147 ... Original oscillation clock signal, 148 ... Timing signal, 150 ... Clock signal

Claims (8)

A sensor module,
A physical quantity sensor that detects a predetermined physical quantity and outputs it as a detection signal;
Including heat-generating components that generate heat when used,
The heat generating component is
Including a switching control unit for switching a plurality of operation modes,
The switching control unit
Switching between a normal operation mode for causing the physical quantity sensor to detect the predetermined physical quantity and outputting output data based on the detection signal, and a warm-up mode for changing the temperature of the physical quantity sensor to a target temperature,
Control so that the warm-up mode is executed before the normal operation mode when a given condition is satisfied;
A sensor module having a saturation temperature in the normal operation mode as the target temperature. The sensor module according to claim 1,
The switching control unit
A sensor module having the given condition as being at startup. The sensor module according to claim 1,
The switching control unit
A clock supplied to the heat-generating component, and a normal operation clock used in the normal operation mode, and a warm-up clock used in the warm-up mode,
A sensor module that uses the highest first frequency among the warm-up clock frequencies including the normal operation clock. The sensor module according to claim 3, wherein
The switching control unit
In the warm-up mode, the frequency of the warm-up clock is set to the first frequency until the temperature of the physical quantity sensor reaches a first temperature exceeding the target temperature, and then the frequency is higher than the first frequency. Sensor module with a low second frequency. The sensor module according to claim 4, wherein
The switching control unit
In the warm-up mode, when the frequency of the warm-up clock is the second frequency and the temperature of the physical quantity sensor becomes a second temperature lower than the target temperature, the warm-up clock A sensor module, wherein a clock frequency is a third frequency lower than the first frequency and higher than the second frequency. The sensor module according to claim 3, wherein
The switching control unit
In the warm-up mode, based on the temperature information, control so that the temperature of the physical quantity sensor does not exceed the target temperature,
A sensor module that lowers the frequency of the warm-up clock as the temperature of the physical quantity sensor approaches the target temperature. The sensor module according to claim 7,
The switching control unit
A sensor module that determines at least one of a frequency and a period of the warm-up clock based on an elapsed time from the start of the warm-up mode. The sensor module according to any one of claims 1 to 7,
The physical quantity sensor
A sensor module that detects at least pressure as the predetermined physical quantity.

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