JP5151642B2 - Device for stabilizing processing speed of asynchronous circuit and on-vehicle electronic device equipped with the same - Google Patents

Description

  The present invention relates to a processing speed stabilizing device for stabilizing the processing speed of an asynchronous circuit regardless of temperature conditions during operation, and an on-vehicle electronic device equipped with the processing speed stabilizing device.

  In recent years, the synchronization circuit, which is the mainstream of digital circuits, has a problem in that power consumption and noise increase as the clock frequency increases. As a solution to this problem, an asynchronous circuit that does not use a synchronous clock has attracted attention. Asynchronous circuits do not use a synchronous clock, and thus have low power consumption and low noise.

  However, since the asynchronous circuit does not use a clock, a mechanism for separately generating the data transfer timing of each circuit module is required. As a typical circuit system for that purpose, there are a two-wire circuit and a bundle data circuit.

  In the two-wire circuit, 1-bit data is encoded as 2-bit data. For example, 1-bit data “0” and “1” are expressed as “01” and “10” in the two-wire system. These are called valid data, and “00” is used as invalid data (spacer). Then, by transmitting valid data and invalid data alternately, it is possible to generate data transfer timing.

  In the bundle data circuit, the data transfer timing is generated by a delay generation circuit. The delay generation circuit is configured by a gate chain having a delay equal to or greater than that of the circuit module, and is activated simultaneously with the start of the circuit module operation. Then, it recognizes that the operation of the circuit module is completed when the output of the delay generation circuit changes. In this way, it is possible to generate the data transfer timing of the circuit module.

  However, in these asynchronous circuit systems, the processing speed changes due to temperature fluctuations and manufacturing variations of the IC chip in which the asynchronous circuit is incorporated, so the processing speed is kept constant as in a synchronous circuit using a clock. I can't keep it.

In order to solve this problem, there is a method of correcting fluctuations in the processing speed of the asynchronous circuit due to temperature or the like by the supply voltage of the asynchronous circuit (see, for example, Patent Document 1). The device described in Patent Document 1 adds a buffer to the output side or the input side of an asynchronous circuit, and controls the voltage supplied from the voltage adjustment circuit to the asynchronous circuit based on a signal indicating the amount of data stored in the buffer. Has a configuration. When the temperature of the asynchronous circuit is low and the processing speed is low, the amount of data stored in the buffer exceeds a certain reference value, so the supply voltage of the asynchronous circuit is lowered to slow down the processing speed. On the contrary, when the temperature is high, the processing of the asynchronous circuit is slowed down. Therefore, the processing speed is increased by increasing the supply voltage to the asynchronous circuit. Thereby, the processing speed of the asynchronous circuit can be made constant.
JP-A-5-265607

  However, the above-described device for controlling the supply voltage to the internal asynchronous electronic circuit by the feedback signal needs to temporarily store input data or output data in the buffer, and actually uses a FIFO for the buffer. It becomes difficult to provide the user with a short response time (time taken from input to output).

  The present invention has been made in view of such problems, and an object of the present invention is to provide an asynchronous circuit processing speed stabilizing device having a response time shorter than that of a conventional device.

  The asynchronous circuit according to claim 1, which has been made to solve such a problem (10: In this column, in order to facilitate understanding of the invention, the “Best Mode for Carrying Out the Invention” column is provided as necessary. The processing speed stabilizing device (5) is a process for keeping the processing speed of the asynchronous circuit (40) constant. A speed stabilizing device (5) comprising a periodic variation pulse generating means (50), a constant periodic pulse generating means (60), a pulse measuring means (70), a voltage adjusting means (80), and a voltage control signal generating means (90 ).

  The period fluctuation pulse generating means (50) generates a period fluctuation pulse whose period changes depending on the processing speed of the asynchronous circuit (40), and the period constant pulse generation means (60) has a period longer than the period of the period fluctuation pulse. A long-period constant pulse having a constant period is generated.

  The pulse measuring means (70) measures the number of pulses generated within a predetermined time, and the voltage adjusting means (80) adjusts the supply voltage to the asynchronous circuit (40), and the voltage control signal generating means (90 ) Generates a voltage control signal to the voltage adjusting means (80).

  Further, the pulse measuring means (70) receives the periodic fluctuation pulse generated by the periodic fluctuation pulse generating means (50) and the constant periodic pulse generated by the constant periodic pulse generating means (60) as input, and the inputted constant periodic pulse. Based on the above, the number of periodically varying pulses generated within a predetermined time is measured, and the measured number of periodically varying pulses is output to the voltage control signal generating means (90).

  The voltage control signal generation means (90) compares the number of periodically varying pulses input from the pulse measuring means (70) with the target pulse number set to stabilize the processing speed, and the period variation occurs from the target pulse number. When the number of pulses is small, a voltage control signal for increasing the supply voltage of the asynchronous circuit (40) is output to the voltage adjusting means (80), and when the number of periodically varying pulses measured is larger than the target number of pulses, the asynchronous circuit (40 ) Is output to the voltage adjusting means (80).

  Further, the voltage adjusting means (80) adjusts the supply voltage of the asynchronous circuit (40) based on the control signal input from the voltage control signal generating means (90), thereby processing speed of the asynchronous circuit (40). To be constant.

According to such a processing speed stabilizing device (5), the processing speed stabilizing device (5) of the asynchronous circuit (40) having a response time shorter than that of the conventional device can be realized. This will be described below.
In general, the asynchronous circuit (40) has a lower processing speed when the operating temperature is higher and a higher processing speed when the operating temperature is lower. Therefore, since the processing speed changes depending on the operating temperature, it is difficult to make the processing speed constant. In order to solve this problem, the voltage dependence of the processing speed, which is another feature of the asynchronous circuit (40), is used.

  When the supply voltage is increased, the asynchronous circuit (40) increases the processing speed, and when the supply voltage is decreased, the processing speed decreases. Using this feature, the difference in the current processing speed that occurs due to changes in the operating temperature is reduced as much as possible by adjusting the supply voltage of the asynchronous circuit (40) with respect to a certain processing speed (target processing speed) to be made constant. To do.

  That is, when the operating temperature of the asynchronous circuit (40) rises and the processing speed becomes slow and a difference with respect to the target processing speed occurs, the supply voltage of the asynchronous circuit (40) is increased in order to make the difference zero. Conversely, when the operating temperature of the asynchronous circuit (40) decreases, the processing speed increases, and a difference occurs with respect to the target processing speed, the supply voltage of the asynchronous circuit (40) is set to make the difference zero. Lower.

  The processing speed stabilizing device (5) according to claim 1 uses a periodic fluctuation pulse whose period varies depending on the processing speed of the asynchronous circuit (40) in order to detect the processing speed of the asynchronous circuit (40). . The period fluctuation pulse generating means (50) can be realized by, for example, a ring oscillator.

If the period variation pulse generating means (50) is provided in the vicinity of the asynchronous circuit (40), the period of the generated pulse varies with temperature in the same manner as the processing speed of the asynchronous circuit (40).
Moreover, if a device that can be designed and manufactured by the same process technology as the asynchronous circuit (40), such as a ring oscillator, is used as the periodic variation pulse generating means (50), the element characteristics of each other are the same, and the asynchronous circuit ( The processing speed of 40) and the pulse period of the period fluctuation pulse generating means (50) have a strong dependency.

  Therefore, the change in the pulse period of the period fluctuation pulse generating means (50) can be used as the change in the processing speed of the asynchronous circuit (40). In addition, since the pulse generation by the period variation pulse generation means (50) can be performed independently of the processing performed by the asynchronous circuit (40), the processing speed overhead of the asynchronous circuit (40) does not occur.

  Here, “in the vicinity of the asynchronous circuit (40)” means a range in which the change in the processing speed of the asynchronous circuit (40) strongly depends on the periodic fluctuation pulse generated by the periodic fluctuation pulse generating means. For example, the asynchronous circuit (40) and the ring oscillator are mixedly mounted on the same IC chip.

  The pulse measuring means (70) receives as input a periodic variation pulse and a periodic constant pulse having a period longer than that of the periodic variation pulse and a constant period. The constant period pulse generating means (60) can be realized by, for example, a high precision crystal oscillator.

The pulse measuring means (70) can detect a change in the period varying pulse period by measuring the number of pulses generated by the period varying pulse means within the period of the constant period pulse.
The voltage control signal generation means (90) receives a control signal to the voltage adjustment means (80) for adjusting the supply voltage of the asynchronous circuit (40) by using the number of measurement pulses obtained by the pulse measurement means (70) as an input. Generate. The voltage control signal generation means (90) compares the number of input measurement pulses with a preset target pulse. Here, the target pulse number indicates a target processing speed to be made constant.

  After the comparison, if the number of measurement pulses is less than the target number of pulses, the voltage control signal generation means (90) determines that the current processing speed is lower than the target processing speed, and determines the number of measurement pulses as the target pulse number. In order to correct the number, a control signal for increasing the supply voltage of the asynchronous circuit (40) is transmitted to the voltage adjusting means (80).

  Conversely, if the number of measurement pulses is larger than the target pulse number, it is determined that the current processing speed exceeds the target processing speed, and the asynchronous circuit (40) is used to correct the measurement pulse number to the target pulse number. A control signal for lowering the supply voltage is sent to the voltage adjusting means (80).

  The voltage adjusting means (80) receives the control signal from the voltage control signal generating means (90) and adjusts the supply voltage of the asynchronous circuit (40). The voltage adjusting means (80) can step up or down the output voltage according to the input voltage and the control signal. By using this output voltage as the supply voltage of the asynchronous circuit (40), the processing speed of the asynchronous circuit (40) can be changed.

  As described above, by configuring the processing speed stabilizing device (5), the processing speed of the asynchronous circuit (40) is constant without buffering, and the time from input to output is shortened compared to the conventional device. Will be able to.

By the way, if the value of the target pulse number set for stabilizing the processing speed is fixed to one, the processing speed cannot be changed or adjusted.

Accordingly, as described in claim 2 , the voltage control signal generation means (90) stores a plurality of target pulse numbers in the storage means (92) capable of storing or rewriting and storing a plurality of target pulses, and the storage means (92). from the target number of pulses, by selecting any one of a number of target pulses, to comprise, a process speed changing means for changing the processing speed of the asynchronous circuit (40, 42) (130) for a predetermined reduction Good.

In this way, the value of the target pulse number can be made variable or multiple, and one can be selected from the multiple, so that the processing speed can be finely adjusted or changed as required. You will be able to

By the way, depending on the user and the intended use of the asynchronous circuit (40, 42), there may be a case where a variation in the processing speed of the asynchronous circuit (40, 42) is allowed to some extent. Therefore, as described in claim 3, in the voltage control signal generating means (90), instead of the target value to limit a numerical value definitive of the number of target pulses, by the use of the target range, that is, to limit certain target value Instead of a value, the target value is given a range and used as a target range.

As a result, the voltage adjustment means (80) does not always operate to set the difference between the measurement value ( number of measurement pulses ) and the target value to 0, but if there is a difference, it is within the target range. Since it is not necessary to operate the means (80), redundant operation can be omitted.

  The processing speed stabilizing device (5, 7, 9) of the asynchronous circuit (40, 42) described above does not need to be constantly operated although it depends on the intended use. For example, the periodic fluctuation pulse generating means (50) of the processing speed stabilizing device (5, 7, 9) of claim 1 is oscillated only when necessary or intermittently without always oscillating. Thus, redundant operation can be omitted.

Therefore, as described in claim 4 , an operation condition acquisition means (110) for acquiring conditions for operating the processing speed stabilizing device (5, 7, 9) of the asynchronous circuit (40, 42), and operation condition acquisition An operation control means (130) for operating the processing speed stabilizing device (5, 7, 9) of the asynchronous circuit (40, 42) only when the operation condition acquired by the means (110) satisfies a predetermined condition; It is advisable to provide

  In this way, the processing speed stabilizing device (5, 7, 9) of the asynchronous circuit (40, 42) can be operated only when a predetermined condition is satisfied, so that redundant operation and excessive operation can be performed. Thus, power consumption and aging degradation as a device can be suppressed.

By the way, when the user can set the operating conditions of the processing speed stabilizing device (5, 7, 9), the processing speed stabilizing device (5, 7, 9) is easy to use for the user. Therefore, as described in claim 5, the apparatus includes an operation condition setting unit (120) for a user to set an operation condition, and the operation condition acquisition unit (110) is set by the operation condition setting unit (120). It is recommended to acquire the operating conditions.

  In this way, the user can set the operation conditions of the processing speed stabilizing device (5, 7, 9), for example, the operation / non-operation of the processing speed stabilizing device (5, 7, 9). Therefore, the processing speed stabilizing device (5, 7, 9) is easy to use.

  By the way, the on-vehicle electronic devices (1, 2) on which the asynchronous circuits (40, 42) are mounted may change the operation state depending on the situation inside or outside the vehicle. For example, when the vehicle-mounted electronic device (1, 2) has a driving support function for supporting safe driving as one function and is configured by an asynchronous circuit (40, 42), the vehicle is at an intersection. When there is a danger of coming into contact with other vehicles while driving or driving, the driving support function is focused on; otherwise, functions other than the driving support function are focused on Conceivable.

Therefore, as described in claim 6 , the vehicle inside / outside situation obtaining means (140) for obtaining the inside or outside situation of the vehicle on which the processing speed stabilizing device (5, 7, 9) is mounted is provided. The operation condition acquisition means (110) may acquire the operation conditions of the asynchronous circuit (40, 42) based on the internal or external situation of the vehicle acquired from the vehicle inside / outside situation acquisition means (140).

  In this way, the processing speed stabilizing device (5, 7, 9) of the asynchronous circuit (40, 42) only when the internal or external situation of the vehicle acquired by the vehicle internal / external status acquisition means (140) satisfies a predetermined condition. When the asynchronous circuit (40, 42) mounted on the in-vehicle electronic device (1, 2) has to be operated as described above, the processing speed stabilizing device (5, 7) is operated. , 9) is operated, the processing speed of the asynchronous circuit (40, 42) can be made constant.

  In other words, the processing speed stabilizing device (5, 7, 9) operates by operating the processing speed stabilizing device (5, 7, 9) only when the asynchronous circuit (40, 42) needs to be operated. The number of times is reduced, the heat generation in the circuit part is suppressed, the power consumption is suppressed to extend the life of the vehicle-mounted battery, the processing speed stabilizing device (5, 7, 9) and the asynchronous circuit (40, 42) ) Over time.

  By the way, the asynchronous circuits (40, 42) need not always operate at the same processing speed. For example, depending on the situation, excessive processing can be omitted by increasing the processing speed only when necessary and by decreasing the processing speed when it is not necessary.

Accordingly, as described in claim 7 , a process for acquiring a processing speed change condition for changing the processing speed of the asynchronous circuit (40, 42) that is made constant by the processing speed stabilizing device (5, 7, 9). Only when the processing speed changing conditions acquired by the speed changing condition acquiring means (110) and the processing speed changing condition acquiring means (110) satisfy a predetermined condition, the processing speed stabilizing device (5, 7, 9). Processing speed change control means (135) for changing the processing speed of the asynchronous circuit (40, 42) to be fixed may be provided.

  In this way, the processing speed of the asynchronous circuit (40, 42) that is stabilized by the processing speed stabilizing device (5, 7, 9) can be changed only when a predetermined condition is satisfied. Operation / excessive operation can be eliminated, and as a result, power consumption and deterioration over time as a device can be suppressed.

  By the way, when the user can set the processing speed change condition of the asynchronous circuit (40, 42) that is stabilized by the processing speed stabilizing device (5, 7, 9), the processing speed that is easy for the user to use. It becomes a stabilizing device (5, 7, 9).

Therefore, as described in claim 8 , the processing speed change condition setting means (120) for the user to set the processing speed change condition is provided, and the operation condition acquisition means (110) is a processing speed condition setting means (110). It is preferable to acquire the processing speed change condition of the asynchronous circuit (40, 42) to be stabilized by the processing speed stabilization processing device (5, 7, 9) set in 120).

  In this way, the user can set the processing speed of the asynchronous circuit (40, 42) that is stabilized by the processing speed stabilizing device (5, 7, 9) with respect to a predetermined condition. It becomes an easy processing speed stabilizing device (5, 7, 9).

  By the way, when the asynchronous circuit (40, 42) is mounted on the vehicle, the operation speed may be changed depending on the situation inside or outside the vehicle. For example, when the asynchronous circuit (40, 42) is incorporated in the in-vehicle electronic device (1, 2) for supporting safe driving, the vehicle may come into contact with other vehicles when approaching an intersection or during traveling. When there is a serious danger, the processing speed of the asynchronous circuit (40, 42) is increased in order to make the driving support function focus, and otherwise, the processing speed of the asynchronous circuit (40, 42) is decreased. It is conceivable that functions other than the driving support function are operated with priority.

Therefore, as described in claim 9 , the vehicle inside / outside situation acquisition means (140) for acquiring the inside or outside situation of the vehicle on which the processing speed stabilizing device (5, 7, 9) is mounted is provided. The processing speed change condition acquisition means (110) sets the processing speed change condition of the processing speed stabilizing device (5, 7, 9) based on the internal or external situation of the vehicle acquired from the vehicle inside / outside situation acquisition means (140). You should get it.

  In this way, an asynchronous circuit (5, 7, 9) that is stabilized by the processing speed stabilizing device (5, 7, 9) when the vehicle internal or external situation acquired by the vehicle inside / outside situation acquisition means (140) satisfies a predetermined condition. 40, 42) can be changed, the asynchronous circuit (40, 42) incorporated in the on-vehicle electronic device (1, 2) as described above has a processing speed according to the inside / outside situation of the vehicle. Can be changed.

  In other words, if the asynchronous circuit is incorporated in the in-vehicle electronic device, for example, if the user sets the processing speed of the asynchronous circuit (40, 42) to be constant for a certain vehicle inside / outside situation A, In the vehicle inside / outside situation A, the heat generation of the asynchronous circuit is suppressed, the power consumption is reduced to extend the life of the vehicle-mounted battery, the processing speed stabilizing device (5, 7, 9) and the asynchronous circuit (40, 42). ) Can be suppressed over time. In addition, for example, if the processing speed of the asynchronous circuit (40, 42) to be fixed is set to a high speed for a certain vehicle inside / outside situation B, the functions of the asynchronous circuit in the vehicle situation B are maximized. be able to.

By the way, the processing speed stabilizing circuit (40, 42) can also suppress power consumption by changing the frequency of comparing the target pulse numbers in addition to changing the operation and processing speed of the circuit.

Therefore, as described in claim 10, it is performed based on the number of comparison times the target number of pulses, in order to change the frequency of the supply voltage setting to the asynchronous circuit (40, 42) by the voltage adjusting means (80) Processing frequency change condition acquisition means (110) for acquiring the processing frequency change condition of the asynchronous circuit (80) by the voltage adjustment means (80) based on the processing frequency change condition acquired by the processing frequency change condition acquisition means (110). 40) and a processing frequency changing means (90, 130) for changing the frequency of the supply voltage to 40).

In this case, the supply voltage setting to the asynchronous circuit (40, 42) by the voltage adjusting means (80) performed based on the target pulse number according to the processing frequency changing condition acquired by the processing frequency changing condition acquiring means (110). You can change the frequency.

  Then, when it is not necessary to frequently perform voltage adjustment, the frequency of voltage adjustment is reduced, so that the processing load is reduced and the processing load is reduced, so that the processing speed stabilization circuit (40, 42) is consumed. Electric power can be suppressed.

  By the way, when the user can change the processing frequency changing condition of the processing speed stabilizing device (5, 7, 9), the processing speed stabilizing device (5, 7, 9) that is easy for the user to use is provided. Become.

Accordingly, as described in claim 11 , the processing frequency change condition setting means (120) for the user to set the processing frequency change condition is provided, and the processing frequency change condition acquisition means (110) includes the processing frequency change condition. The processing frequency change condition of the processing speed stabilization processing device (5, 7, 9) set by the setting means (120) may be acquired.

  In this way, the user can change the processing frequency changing condition of the processing speed stabilizing device (5, 7, 9), that is, the processing frequency of the processing speed stabilizing device (5, 7, 9). Therefore, the processing speed stabilizing device (5, 7, 9) is easy to use.

By the way, when the asynchronous circuit (40, 42) is mounted on the vehicle, the operation speed may be changed depending on the situation inside or outside the vehicle as described above. Therefore, as described in claim 12 , the vehicle inside / outside situation obtaining means (140) for obtaining the inside or outside situation of the vehicle on which the processing speed stabilizing device (5, 7, 9) is mounted is provided. The processing frequency change condition acquisition means (110) sets the processing frequency change condition of the processing speed stabilizing device (5, 7, 9) based on the internal or external situation of the vehicle acquired from the vehicle inside / outside situation acquisition means (140). You should get it.

  In this way, the processing speed stabilizing device (5, 7, 9) of the asynchronous circuit (40, 42) only when the internal or external situation of the vehicle acquired by the vehicle internal / external status acquisition means (140) satisfies a predetermined condition. The processing frequency can be changed.

  Therefore, for example, if the user sets the processing frequency per unit time of the processing speed stabilizing device (5, 7, 9) low in a certain vehicle inside / outside situation C, the processing speed stabilizing device in the inside / outside situation C of the vehicle. (5, 7, 9) reduces the frequency of setting the supply voltage to make the processing speed of the asynchronous circuit (40, 42) constant, thereby suppressing the heat generation of the circuit part and the power consumption. It is possible to extend the life of the vehicle-mounted battery and to suppress the deterioration over time of the processing speed stabilizing device (5, 7, 9).

  Conversely, for example, if the user sets a high processing frequency per unit time of the processing speed stabilizing device (5, 7, 9) in a certain vehicle inside / outside situation D, the processing speed stabilizing device (5, 7, 9) Since the frequency of setting the supply voltage to make the processing speed of the asynchronous circuit (40, 42) constant becomes high, the processing speed of the asynchronous circuit (40, 42) is constant with high accuracy in the vehicle inside / outside situation D. Can be

The on-vehicle electronic device (1, 2) according to claim 13 is a processing speed stabilizing device (5, 7, 9) of the asynchronous circuit (40, 42) according to any one of claims 1 to 12. It is provided with. Such an in-vehicle electronic device (1, 2) has the features described in claims 1 to 9 .

Embodiments to which the present invention is applied will be described below with reference to the drawings. The embodiment of the present invention is not limited to the following embodiment, and can take various forms as long as they belong to the technical scope of the present invention.
[First Embodiment]
FIG. 1 is a block diagram showing a schematic configuration of a driving support device 1 on which a processing speed stabilizing device 5 according to the present invention is mounted.

  The driving support device 1 is a device for driving support that has a car navigation function, receives radio waves from roadside devices such as ETC, and provides ETC and other information services. As shown in FIG. A position detector 10, a data input device 20, an operation switch group 22, a control device 30, an external memory 32, an audio output device 34, a display device 36, and a processing speed stabilizing device 5 are provided.

  The position detector 10 includes a known geomagnetic sensor 12, gyroscope 14, distance sensor 16, and GPS receiver 18. Since these sensors 12, 14, 16, and 18 have errors of different properties, they are configured so that the position of the vehicle can be detected while interpolating with a plurality of sensors. Depending on the accuracy, the sensor may be constituted by a part of the above-described sensors, and further, a steering rotation sensor and a wheel sensor of each rolling wheel may be used.

  The data input device 20 is a device for inputting various data including so-called map matching data, map data, and landmark data in order to improve position detection accuracy. As a medium, a CD-ROM or DVD is generally used because of its data amount, but a medium such as a memory card or an HDD device may be used.

  The operation switch group 22 is a switch for a user such as a driver to operate the driving support device 1. For example, a touch switch or a mechanical switch integrated with the display device 36 is used.

  In addition, the operation switch group 22 selects one of a plurality of target pulse numbers stored in the memory 92 of the voltage control signal generation unit 90 of the processing speed stabilizing device 5 described later, and performs processing of the asynchronous circuit 40. It is also used to change the speed and rewrite the value of the target pulse number.

  The external memory 32 is an HDD device or a memory stick, and stores various data such as voice data output from the voice output device 34 and personal information of the driver used for various settings of the driving support device 1.

  The audio output device 34 includes a speaker, an audio amplifier, and the like (not shown). The sound to be output is data stored in the external memory 32 or synthesized by the control device 30.

  Further, the audio output device 34 can be omitted as a component device of the driving support device 1. In that case, for example, an audio output device provided in another device such as an audio device of the vehicle main body may be used.

  The display device 36 displays a plurality of selection switch images (corresponding to the touch switches of the operation switch group 22) for operating a map and equipment for route guidance, and from an LCD, an organic EL display, or the like. Constructed and color display is possible.

  Further, on the image of the display device 36, the vehicle current position mark input from the position detector 10, the map data input from the data input device 20, and additional data such as a guide route to be displayed on the map are displayed in an overlapping manner. Can do.

The control device 30 includes a CPU, ROM, RAM, I / O (not shown), a bus line connecting these, and the like.
When a destination is input from the operation switch group 22, the control device 30 automatically selects an optimum route from the current position to the destination, calculates a guidance route, and displays it on the display device 36. It has a route guidance function. As a method for automatically calculating the optimum route, a known method such as the Dijkstra method is used.

In addition to executing the route guidance function, the control device 30 performs an operation output of another device based on an operation command input from the operation switch group 22.
The processing speed stabilizing device 5 is provided in the control device 30 and is a device for keeping the processing speed of the asynchronous circuit 40 constant in the portion of the control device 30 that is configured by the asynchronous circuit 40.

(Configuration of processing speed stabilizing device 5)
Next, the processing speed stabilizing device 5 will be described with reference to FIG. FIG. 2 is a block diagram showing a schematic configuration of the processing speed stabilizing device 5.

  As shown in FIG. 2, the processing speed stabilizing device 5 includes a periodic fluctuation pulse generating unit 50, a periodic constant pulse generating unit 60, a pulse measuring unit 70, a voltage regulator 80, a voltage control signal generating unit 90, an operation / processing speed. A change condition acquisition unit 110, an operation / processing speed change condition setting unit 120, and an operation / processing speed change control unit 130 are provided.

  The period fluctuation pulse generation unit 50 generates a period fluctuation pulse whose period changes depending on the processing speed of the asynchronous circuit 40. In the first embodiment, the period variation pulse generation unit 50 is configured by a ring oscillator having an oscillation frequency of 64 MHz at an operating temperature of 25 ° C. Since the oscillation frequency of the ring oscillator varies depending on the operating temperature as well as the processing speed of the asynchronous circuit 40, the ring oscillator can generate a periodic variation pulse whose period depends on the processing speed of the asynchronous circuit 40.

  The constant period pulse generation unit 60 generates a constant period pulse having a constant period. The constant cycle pulse generator 60 generates a constant cycle pulse whose cycle is always constant with respect to temperature fluctuations and whose cycle length is sufficiently larger than the periodic fluctuation pulse.

  In the first embodiment, the constant-period pulse generation unit 60 is configured using a high-precision crystal oscillator with an oscillation frequency of 32 KHz. Since the crystal oscillator can make the oscillation frequency constant with extremely high accuracy with respect to the operating temperature, it can generate a constant period pulse.

  The pulse measuring unit 70 measures the number of pulses generated within a predetermined time, and inputs the periodic variation pulse generated by the periodic variation pulse generation unit 50 and the periodic constant pulse generated by the periodic constant pulse generation unit 60. As described above, the number of period fluctuation pulses generated within the period of the constant period pulse is measured, and the number of measurement pulses is output to the voltage control signal generation unit 90.

  In the first embodiment, the pulse measuring unit 70 is configured using a 12-bit binary counter. This binary counter receives the periodic variation pulse generated by the periodic variation pulse generation unit 50 and the constant periodic pulse generated by the constant periodic pulse generation unit 60 as an input, and the number of periodic variation pulses generated within the period of the constant periodic pulse. Count.

  The pulse measuring unit 70 (binary counter) resets the counter at the same time as the rise of the constant cycle pulse (first time) and starts counting the period variation pulse, and at the same time as the next rise of the constant cycle pulse (second time). Hold the value of the counter.

  For example, assuming that the operating temperature of the asynchronous circuit 40 is normal temperature, the frequency of the constant period pulse is 32 KHz and the frequency of the period variation pulse is 64 MHz, so the count value 2000 is held as the number of measurement pulses from 64 MHz / 32 kHz. . Then, the held number of measurement pulses is output to the voltage control signal generation unit 90.

  The voltage regulator 80 adjusts the supply voltage to the asynchronous circuit 40, and adjusts the supply voltage of the asynchronous circuit 40 based on the voltage control signal input from the voltage control signal generation unit 90. The processing speed of the circuit 40 is made constant. Since the voltage regulator 80 is well-known (for example, 1 is described in patent document), detailed description is abbreviate | omitted.

  The voltage control signal generation unit 90 generates a voltage control signal to the voltage regulator 80, and includes the number of periodic fluctuation pulses input from the pulse measurement unit 70, the target pulse number set for stabilizing the processing speed, and the like. When the number of periodically varying pulses is less than the target pulse number, a voltage control signal for increasing the supply voltage of the asynchronous circuit 40 is output to the voltage regulator 80, and when the number of pulses measured is larger than the target pulse number, A voltage control signal for lowering the supply voltage of the asynchronous circuit 40 is output to the voltage regulator 80.

  Therefore, the voltage control signal generation unit 90 includes a memory 92 and a comparator 94. The memory 92 is a memory that can store and rewrite a plurality of target pulse numbers, and the comparator 94 includes the number of periodically varying pulses input from the pulse measuring unit 70 and the target pulse number stored in the memory 92. Are compared.

The voltage control signal generation unit 90 performs the following processes (A) to (G).
(A) After the pulse measurement unit 70 holds the counter value, the number of measurement pulses is input from the pulse measurement unit 70.

(A) The comparator 94 compares the input measurement pulse number with the target pulse number stored in the memory 92.
(D) If the number of measurement pulses is less than the target number of pulses stored in the memory 92, a voltage control signal (+ ΔV) for increasing the supply voltage of the asynchronous circuit 40 is output to the voltage regulator 80.

(E) If the number of measurement pulses is larger than the target number of pulses, a voltage control signal (−ΔV) for lowering the supply voltage of the asynchronous circuit 40 is output to the voltage regulator 80.
(G) If the number of measurement pulses is equal to the target number of pulses, a voltage control signal (correction unnecessary signal) for maintaining the current supply voltage of the asynchronous circuit 40 is output.

  The operation / processing speed changing condition setting unit 120 is used by the user to set conditions. The operation / non-operation conditions of the processing speed stabilizing device 5 or the processing to be constant by the processing speed stabilizing device 5 is used. This is a switch for the user to set a change condition for changing the speed or the comparison frequency between the number of measurement pulses and the target pulse number.

  How often the user wants to operate the processing speed stabilizing device 5 for a certain situation, or in what situation the processing speed stabilizing device 5 wants to change the processing speed, Alternatively, the operation / processing speed change condition setting unit 120 sets whether to change the comparison frequency between the number of measurement pulses and the target pulse.

  The operation / processing speed change condition acquisition unit 110 operates according to the conditions set by the operation / processing speed change condition setting unit 120 (operation-on frequency for each situation), processing speed change conditions, or processing frequency change conditions (hereinafter referred to as “processing frequency change conditions”). These conditions are also referred to as operation / processing speed change conditions).

  The operation / processing speed change control unit 130 sets the processing speed stabilizing device 5 of the asynchronous circuit 40 only when the operation / processing speed change condition acquired by the operation / processing speed change condition acquisition unit 110 satisfies a predetermined condition. Make it work.

  Specifically, the operation / processing speed change control unit 130 sets, for example, an operation frequency of the operation / processing speed change condition acquired by the operation / processing speed change condition acquisition unit 110 if it is an operation condition. Based on the above, the crystal oscillator of the constant period pulse generator 60 is operated to generate a pulse, and when the operation is off, the crystal oscillator is stopped to stop the pulse.

  If the processing speed change condition is satisfied, the target pulse number stored in the voltage control signal generation unit 90 is changed to change the processing speed of the asynchronous circuit 40 to be made constant. Furthermore, if the processing frequency change condition is satisfied, the comparison frequency with the target pulse number in the voltage control signal generation unit 90 is changed.

(Operation of processing speed stabilizing device 5)
In the first embodiment, at the operation frequency set by the user, the operation / processing speed change control unit 130 operates the crystal oscillator of the constant period pulse generation unit 60 to generate a pulse, and the processing speed stabilization device 5 Start operation.

  When the operation starts, the comparator 94 detects three equivalent patterns with the number of measurement pulses larger or smaller than the target number of pulses, and outputs them to the voltage regulator 80 as a voltage control signal. Then, by comparing the measurement of the period variation pulse with the target pulse number and generating the voltage control signal a plurality of times, the operation is performed to correct the measurement pulse number to the target pulse number.

  For example, assuming that the target pulse number stored in the memory 92 is 1900, the measurement pulse number 2000 is 100 more than the target pulse number, so that the supply voltage of the asynchronous circuit 40 is controlled by −ΔV (for example, 0.05 V lower). The signal is output to the voltage regulator 80.

  In the next measurement, when 1950 is obtained as the number of measurement pulses, it is 50 more than the target number of pulses 1900, so the supply voltage of the asynchronous circuit 40 is again set to -ΔV (lower by 0.05 V) as a voltage control signal. Output to the regulator 80.

Finally, when the number of measurement pulses matches the number of target pulses 1900, a correction unnecessary signal is output until a difference occurs again between the number of measurement pulses and the number of target pulses.
As described above, the comparator 94 compares the number of measurement pulses with the target number of pulses, and the comparison frequency is changed based on the comparison frequency changed by the operation / processing speed change control unit 130.

(Features of the driving support device 1)
According to the driving support device 1 as described above, the processing speed of the asynchronous circuit 40 having a shorter response time than the conventional device (the device of Reference 1) can be made constant. Since the processing speed of the asynchronous circuit 40 changes depending on the operating temperature, it is difficult for a general driving support apparatus having the asynchronous circuit 40 to keep the processing speed constant.

  However, in the driving assistance device 1, when the operating temperature of the asynchronous circuit 40 increases, the operating temperature of the ring oscillator provided in the asynchronous circuit 40 increases in the same manner. And the period of the pulse which a ring oscillator generates becomes long. On the contrary, when the operating temperature of the asynchronous circuit 40 decreases, the operating temperature of the ring oscillator also decreases in the same manner, so that the period of pulses generated by the ring oscillator is shortened.

  The number of periodic fluctuation pulses generated by the ring oscillator is measured by the pulse measuring unit 70 between the falling and rising of the constant periodic pulse generated by the constant periodic pulse generating unit 60, and the measured number of pulses is set in advance. The compared target pulses are compared by the comparator 94, and if the number of measurement pulses is less than the target pulse number, the voltage control signal generator 90 determines that the current processing speed is lower than the target processing speed, In order to correct the number of measurement pulses to the target number of pulses, a control signal for increasing the supply voltage to the asynchronous circuit 40 is transmitted to the voltage regulator 80.

  Conversely, if the number of measurement pulses is greater than the target pulse number, it is determined that the current processing speed exceeds the target processing speed, and the asynchronous circuit 40 is supplied to correct the measurement pulse number to the target pulse number. A control signal for lowering the voltage is transmitted to the voltage regulator 80.

The voltage regulator 80 receives the control signal from the voltage control signal generator 90 and adjusts the supply voltage of the asynchronous circuit 40 by raising and lowering it.
As described above, according to the driving support device 1 having the processing speed stabilizing device 5, the processing speed of the asynchronous circuit 40 is made bufferless and the time from input to output is shortened compared to the conventional device. Will be able to.

  Further, since the pulse generation by the period fluctuation pulse generation unit 50 (ring oscillator) can be performed independently of the processing performed by the asynchronous circuit 40, the processing speed overhead of the asynchronous circuit 40 does not occur.

  Furthermore, when the user sets an operation condition (operation frequency), a processing speed, or a condition for changing the comparison frequency in the operation condition setting unit, the operation speed stabilizing device 5 of the asynchronous circuit 40 can be operated redundantly or asynchronously. It is possible to eliminate the excessive processing speed of the circuit 40, and consequently, it is possible to suppress power consumption as a device and aging degradation of the device and the asynchronous circuit 40.

[Second Embodiment]
Next, a second embodiment will be described with reference to FIGS. FIG. 3 is a block diagram illustrating a schematic configuration of the driving support device 2, and FIG. 4 is a block diagram illustrating a schematic configuration of the processing speed stabilizing device 7 mounted on the driving support device 2. Since the driving support apparatus 2 in the second embodiment has many parts in common with the driving support apparatus 1 in the first embodiment, the common parts are denoted by the same reference numerals and description thereof is omitted.

  As shown in FIG. 3, the driving support device 2 is obtained by adding a millimeter wave radar 140 to the driving support device 1. The millimeter wave radar 140 is for acquiring a surrounding situation when the vehicle on which the driving support apparatus 2 is mounted is traveling, and detects a person in front of the vehicle and other vehicles.

  The millimeter wave radar 140 transmits a millimeter wave radio wave, receives a reflected wave of the transmitted radio wave, and receives the reflected wave reception intensity, reception direction, and the distance from the Doppler shift of the reflected wave to a person in front of the vehicle or another vehicle And detect azimuth and relative speed.

  The processing speed stabilizing device 7 is a processing speed stabilizing device that maintains a constant processing speed of the asynchronous circuit 42 that can be controlled by the program. As shown in FIG. 3, the asynchronous circuit 42 that implements the processing speed stabilizing program, It is composed of a constant period pulse generation unit 60, a voltage regulator 80, an operation / processing speed change condition acquisition unit 110, and an operation / processing speed change control unit 130. Note that the constant-period pulse generation unit 60 and the voltage regulator 80 are the same as those in the first embodiment, and a description thereof will be omitted.

  The operation / processing speed change condition acquisition unit 110 acquires a situation outside the vehicle (distance, direction and relative speed of a person in front of the vehicle or another vehicle) from the millimeter wave radar 140, and the operation / processing speed change control unit 130 The operation frequency of the processing speed stabilizing device 7 of the asynchronous circuit 42, the processing speed of the asynchronous circuit 42, and the comparison frequency are changed when the external situation of the vehicle acquired from the operation / processing speed change condition acquisition unit 110 satisfies a predetermined condition. To do.

  In this case, the predetermined condition is that the distance of the person or other vehicle is within a certain distance (for example, 100 m) from the vehicle, the azimuth is within a certain distance (for example, 5 m) from the vehicle width, and When approaching the direction of the vehicle.

  The operation / processing speed change control unit 130 changes the operation frequency of the processing speed stabilizing device 7 of the asynchronous circuit 42 only when the external condition of the vehicle acquired from the operation / processing speed change condition acquisition unit 110 satisfies a predetermined condition. Or rewriting a target instruction number (to be described later) for making the processing speed stored in the memory inside the asynchronous circuit 42 constant, or changing the processing speed of the asynchronous circuit 42, or measuring the instruction number and the target Change the frequency of comparison with the number of instructions.

  The asynchronous circuit 42 outputs to the voltage regulator 80 a voltage control signal for adjusting the supply voltage to the input unit for inputting the constant cycle pulse generated by the constant cycle pulse generation unit 60 and the voltage regulator 80. A signal output unit is provided.

In addition, the asynchronous circuit 42 is mounted with a program (processing speed stabilization processing program) that can execute the following processes (a) to (c).
(H) The number of instructions of the asynchronous circuit 42 that can be executed within a predetermined time is measured based on the inputted constant period pulse.

(G) Compare the measured number of instructions with the target number of instructions set to stabilize the processing speed.
(G) When the number of measurement instructions is less than the target instruction number, a voltage control signal for increasing the voltage supplied to the asynchronous circuit 42 is output to the voltage regulator 80.

(S) If the number of measurement instructions is higher than the target instruction number, a voltage control signal for lowering the voltage supplied to the asynchronous circuit 42 is output to the voltage regulator 80.
(Processing speed stabilization program processing contents)
Next, processing contents of the processing speed stabilization program will be described with reference to FIG. FIG. 5 is a flowchart showing the processing contents of the processing speed stabilization program. In the processing speed stabilization program, as shown in FIG. 5, an operation / processing speed change command is acquired from the operation / processing speed change control unit 130 in S100, and in S105, an operation / processing speed change command is issued in S100. It is determined whether or not it has been acquired.

  When it is determined that the operation / processing speed change command has been acquired (S105: Yes), the process proceeds to S110, and when it is determined that the operation / processing speed change command cannot be acquired (S105: No), the processing Is returned to S100.

  In S110, of the operation / processing speed change commands acquired in S105, the frequency of comparing the measured command count with the target command count is acquired, and the operation waits based on the value. In other words, if the comparison frequency acquired in S105 is set to the maximum value, the standby is eliminated, the process proceeds to S115, and the standby time is increased as the acquired comparison frequency becomes lower. After the elapse of time, the process proceeds to S115.

  In S115, the register 45 in the asynchronous circuit 42 is reset, and in S120, the increment of the register 45 is started at the falling edge of the constant cycle pulse input from the constant cycle pulse generation unit. In subsequent S125, the increment of the register 45 is stopped at the rising edge of the constant period pulse input from the constant period pulse generation unit.

  In the subsequent S130, the increment value is acquired from the register 45, and in the subsequent S135, the increment value acquired in S130 is compared with the target value. This target value is a target value specified in the processing speed change command acquired in S100. Therefore, the target value is changed according to the external situation obtained by the millimeter wave radar 140, so that the processing speed is changed.

  In subsequent S140, it is determined whether or not to correct the supply voltage. That is, in the comparison between the increment value and the target value in S135, if the increment value and the target value are different (S140: Yes), it is determined to correct the supply voltage, and the process proceeds to S145, where the increment is performed. When the value and the target value are the same (S140: No), it is determined not to correct the supply voltage, and the process proceeds to S150.

In S145, after a voltage control signal for correcting ± ΔV is output to the voltage regulator 80, the process returns to S100, and the processing speed stabilization process is repeated.
That is, when the increment value is larger than the target value, a preset value of −ΔV is output to the voltage regulator 80 as a voltage control signal, and when the increment value is smaller than the target value, After a preset value of + ΔV is output to the voltage regulator 80 as a voltage control signal, the process returns to S100, and the processing speed stabilization process is repeated.

In S150, after the correction unnecessary signal is output to the voltage regulator 80, the process is returned to S100, and the processing speed stabilization process is repeated.
(Features of the driving support device 2)
In the driving support device 2 as described above, the asynchronous circuit 42 that can be controlled by the program measures the number of instructions of the asynchronous circuit 42 that can be executed within a predetermined time based on the inputted constant period pulse, When the number of measured instructions is smaller than the target instruction number, the voltage control signal for increasing the voltage supplied to the asynchronous circuit 42 is output to the voltage regulator 80. If the number of measurement commands is higher than the target number of commands, the voltage control signal for lowering the voltage supplied to the asynchronous circuit 42 is programmed to be output to the voltage regulator 80.

The voltage regulator 80 receives the control signal from the voltage control signal generator 90 and adjusts the supply voltage of the asynchronous circuit 42.
As described above, when the asynchronous circuit 42 can be controlled by a program such as a microcomputer, the additional circuit can be made small and the processing speed can be made constant by effectively utilizing the function originally provided in the asynchronous circuit 42.

  As described above, the function of the asynchronous circuit 42 originally provided is used to substitute the additional circuit for stabilizing the processing speed shown in the first embodiment, and further, the processing speed of the asynchronous circuit 42 is made constant while the reference circuit 1 is described. With the configuration in which the processing speed is made constant by using the feedback signal of the buffer, it is possible to shorten the time required from the input to the output of the asynchronous circuit 42.

  Further, only when the external situation of the traveling vehicle acquired by the millimeter wave radar 140 satisfies a predetermined condition, the operation speed of the processing speed stabilizing device 7 of the asynchronous circuit 42 is increased to increase the accuracy of the processing speed to be stabilized. Or the processing speed of the asynchronous circuit 42 to be fixed can be changed at high speed, or the frequency of comparing the measured number of instructions with the target number of instructions can be changed.

  In other words, when the processing speed of the asynchronous circuit 42 does not have to be constant with high accuracy, or the constant processing speed does not have to be increased, the number of operations of the processing speed stabilizing device 7 is reduced. Or, by changing the processing speed that is stabilized by the processing speed stabilizing device 7 to a low speed, or by reducing the frequency of comparing the measured number of instructions with the target number of instructions, The power consumption can be suppressed to extend the life of the vehicle-mounted battery, and the aging deterioration of the processing speed stabilizing device 7 and the asynchronous circuit 42 can be suppressed.

[Third Embodiment]
In 3rd Embodiment, since the structure of the driving assistance device is the same as the driving assistance device 1 in 1st Embodiment, description of the driving assistance device 1 is abbreviate | omitted. In addition, since the processing speed stabilizing device 9 in the third embodiment has many parts in common with the processing speed stabilizing device 5 in the first embodiment, the common parts are denoted by the same reference numerals and description thereof is omitted. .

  FIG. 6 is a block diagram showing a schematic configuration of the processing speed stabilizing device 9. As illustrated in FIG. 6, the processing speed stabilizing device 9 includes an asynchronous circuit 40, an operating temperature sensor 100, a voltage adjustment unit 80, and a voltage control signal generation unit 90.

  The operating temperature sensor 100 measures the operating temperature inside or on the surface of the asynchronous circuit 40. Thermistor, chromel, and the like that are attached to the components of the asynchronous circuit 40 whose characteristics are easily changed by heat. It is a temperature measuring element such as an alumel thermocouple.

  The voltage control signal generation unit 90 includes a memory 92 and a comparator 96. The memory 92 is a storage device that stores a correspondence table of measured operation temperature values and supply voltages set to stabilize the processing speed, and the comparator 96 is a measurement operation of the asynchronous circuit 40 input from the operation temperature sensor 100. The temperature value is compared with the operating temperature value of the correspondence table stored in the memory 92.

  An example of this correspondence table is shown in FIG. The correspondence table of FIG. 7 is composed of a combination of a measurement operation temperature for making the processing speed of the asynchronous circuit 40 constant and a supply voltage to the asynchronous circuit 40, and may be obtained by simulation before design. The temperature characteristics may be obtained and set after the asynchronous circuit 40 is manufactured.

  In addition, the voltage control signal generation unit 90 inputs the operating temperature of the asynchronous circuit 40 from the operating temperature sensor 100, and sets the supply voltage based on the correspondence table stored in the memory 92 from the input operating temperature of the asynchronous circuit 40. The voltage control signal is output to the voltage regulator 80 using the set supply voltage as a voltage control signal.

  In the correspondence table shown in FIG. 7, a temperature range of ± 0.5 [° C.] is defined with respect to the measured operating temperature value, and when the measured operating temperature value falls within this temperature range, the measured temperature value is The corresponding supply voltage is output. For example, when the operating temperature value is 50.1 [° C.], a supply voltage of 2.05 [V] is output.

(Operation of processing speed stabilizing device 9)
In the processing speed stabilizing device 9 configured as described above, the operation frequency set by the user in the operation / processing speed changing condition setting unit 120 or the comparison frequency between the measured operating temperature and the operating temperature value in the correspondence table is changed. The operation of the processing speed stabilizing device 9 starts based on the change condition for doing so.

  When the operation starts, the operating temperature sensor 100 arranged in or on the surface of the asynchronous circuit 40 measures the operating temperature of the asynchronous circuit 40 and outputs the measured operating temperature value to the voltage control signal generator 90.

  Next, the voltage control signal generation unit 90 receives the measured operating temperature value as an input, and sets the voltage based on the correspondence table of the measured operating temperature value and the supply voltage to the asynchronous circuit 40 set to stabilize the processing speed. A control signal is output to the adjuster 80.

  At this time, the comparator 96 of the voltage control signal generation unit 90 compares the measured operating temperature with the operating temperature value of the correspondence table. This comparison frequency is changed by the operation / processing speed change control unit 130. It is changed based on the comparison frequency.

The voltage regulator 80 receives the control signal from the voltage control signal generator 90 and adjusts the supply voltage of the asynchronous circuit 40.
In the driving support device 1 as described above, the operating temperature of the asynchronous circuit 40 is measured by the operating temperature sensor 100 disposed inside or on the surface of the asynchronous circuit 40, and the operating speed of the asynchronous circuit 40 is set to be constant. The supply voltage to the asynchronous circuit 40 is adjusted from the correspondence table between the measured operating temperature value and the supply voltage of the asynchronous circuit 40.

  As described above, when the asynchronous circuit 40 is used in an environment where the operating temperature changes slowly, by using the processing speed stabilizing device 9, the processing speed of the asynchronous circuit 40 can be kept constant with a simpler configuration than before. Can be

  In addition, the numerical value in the correspondence table between the measured operation temperature value and the supply voltage is used as a target range with a range. Therefore, the voltage regulator 80 does not always operate in order to set the difference between the measured operating temperature value and the target value to 0. If there is a difference, but is within the target range, the voltage regulator 80 is operated. Therefore, redundant operations can be omitted.

Further, the user reselects the operation condition (operation frequency) and the processing speed change condition in the operation / processing speed change condition setting unit 120 (in some circumstances, the correspondence table of the measured operation temperature value and the supply voltage of the asynchronous circuit 40). Or changing the processing speed of the asynchronous circuit 40) or setting the frequency of comparison between the measured temperature and the operating temperature value of the correspondence table, the redundant operation of the processing speed stabilizing device 9 of the asynchronous circuit 40, or asynchronous It is possible to eliminate the excessive processing speed of the circuit 40, and consequently, it is possible to suppress power consumption as a device and aging degradation of the device and the asynchronous circuit 40.
[Other Embodiments]
(1) In the above embodiment, the processing speed stabilizing devices 5, 7, 9 use one target value (target pulse number, target command number) or one correspondence table of measured operation temperature value and supply voltage. The processing speed of the memory 92 and the asynchronous circuit 40 may be selected or set by the user.

  For example, the voltage control signal generation unit 90 shown in FIG. 2 stores not only one target pulse number 1900 but also three other target pulse numbers 1800 and 1700 in total. By making it possible to select from the operation switch group 22 according to the above, it is possible to have three types of processing speeds that can be made constant. Furthermore, by enabling the user to rewrite the target number of pulses, it becomes possible to adjust the processing speed to a desired level within an allowable range.

  (2) In the first embodiment, a ring oscillator is used as the period fluctuation pulse generation unit 50. However, in addition to the ring oscillator, for example, a certain amount of processing ends in addition to normal processing performed by the asynchronous circuit 40. You may comprise the mechanism which outputs a pulse for every. This mechanism can be used as the period fluctuation pulse generation unit 50 because the oscillation frequency of the pulse changes as in the case of the ring oscillator when the processing speed changes according to the temperature change.

  (3) In the first embodiment, ΔV is a fixed value as the control voltage value. However, ΔV may be determined according to the difference between the number of measurement pulses and the target pulse number. Thereby, the correction time required for making the processing speed of the asynchronous circuit 40 constant can be shortened.

  (4) In the second embodiment, the situation outside the vehicle is acquired by the millimeter wave radar 140, but the processing speed may be changed by acquiring the situation inside the vehicle. As the situation inside the vehicle, the driving state of the driver can be considered.

  That is, if the driver's eyelid is kept closed for a certain time from the driver's face image acquired by a CCD camera installed so that the driver's face image can be acquired in the front part of the passenger compartment, the driver's face image is a doze state. It can be considered that the processing speed of the driving support device 2 is increased.

It is a block diagram which shows the structure of the outline of the driving assistance apparatus 1 by which the processing speed stabilization apparatus 5 is mounted. 3 is a block diagram showing a schematic configuration of a processing speed stabilizing device 5. FIG. It is a block diagram which shows the structure of the outline of the driving assistance apparatus 2 in which the processing speed stabilization apparatus 7 is mounted. 3 is a block diagram showing a schematic configuration of a processing speed stabilizing device 7. FIG. It is a flowchart which shows the processing content of a processing speed fixed program. 3 is a block diagram showing a schematic configuration of a processing speed stabilizing device 9. FIG. It is a correspondence table | surface of measured operation temperature value and supply voltage.

Explanation of symbols

  DESCRIPTION OF SYMBOLS 1,2 ... Driving assistance device 5,7,9 ... Processing speed stabilizing device, 10 ... Position detector, 12 ... Geomagnetic sensor, 14 ... Gyroscope, 16 ... Distance sensor, 18 ... GPS receiver, 20 ... Data Input device, 22 ... operation switch group, 30 ... control device, 32 ... external memory, 34 ... audio output device, 36 ... display device, 40, 42 ... asynchronous circuit, 45 ... register, 50 ... periodic fluctuation pulse generator, 60 ... Periodic pulse generation unit, 70 ... Pulse measurement unit, 80 ... Voltage regulator, 90 ... Voltage control signal generation unit, 92 ... Memory, 94, 96 ... Comparator, 100 ... Operating temperature sensor, 110 ... Operation / processing speed Change condition acquisition unit, 120... Operation / processing speed change condition setting unit, 130... Operation / processing speed change control unit, 140.

Claims (13)

A processing speed stabilizing device that keeps the processing speed of an asynchronous circuit constant,
Periodic fluctuation pulse generating means for generating a periodic fluctuation pulse whose period changes depending on the processing speed of the asynchronous circuit;
A period constant pulse generating means for generating a period constant pulse having a period longer than the period of the period variation pulse and a constant period;
A pulse measuring means for measuring the number of pulses generated within a certain period of time;
Voltage adjusting means for adjusting a supply voltage to the asynchronous circuit;
Voltage control signal generating means for generating a voltage control signal to the voltage adjusting means;
With
The pulse measuring means includes
The periodic fluctuation pulse generated by the periodic fluctuation pulse generating means and the periodic constant pulse generated by the constant periodic pulse generating means are input, and the number of periodic fluctuation pulses generated within the period of the inputted constant periodic pulse is measured. And output the measured number of periodically varying pulses to the voltage control signal generating means,
The voltage control signal generating means is
The number of periodically varying pulses input from the pulse measuring means is compared with the number of target pulses set to stabilize the processing speed, and when the number of periodically varying pulses is less than the target number of pulses, the asynchronous circuit A voltage control signal for increasing the supply voltage is output to the voltage adjusting means, and when the number of period fluctuation pulses is larger than the target pulse number, a voltage control signal for decreasing the supply voltage of the asynchronous circuit is output to the voltage adjusting means. ,
The voltage adjusting means is
The processing speed of the asynchronous circuit is made constant by adjusting the supply voltage of the asynchronous circuit based on the voltage control signal input from the voltage control signal generating means. Device. In the asynchronous circuit processing speed stabilizing device according to claim 1 ,
The voltage control signal generating means is
Storage means capable of storing a plurality of the target pulse numbers or storing them by rewriting;
A processing speed changing means for changing a processing speed to be constant by selecting any one of the target pulse numbers from the target pulse numbers stored in the storage means;
An apparatus for stabilizing the processing speed of an asynchronous circuit, comprising: In the asynchronous circuit processing speed stabilizing device according to claim 1 or 2 ,
The voltage control signal generating means is
A processing speed stabilizing device for an asynchronous circuit, wherein a permissible range is provided for a processing speed to be stabilized by using a target range instead of a target value for limiting a numerical value in the target pulse number. In the asynchronous circuit processing speed stabilizing device according to any one of claims 1 to 3 ,
Operating condition acquisition means for acquiring conditions for operating the processing speed stabilizing device of the asynchronous circuit;
Operation control means for operating the processing speed stabilizing device of the asynchronous circuit only when the operation condition acquired by the operation condition acquisition means satisfies a predetermined condition;
An apparatus for stabilizing the processing speed of an asynchronous circuit, comprising: In the asynchronous circuit processing speed stabilizing device according to claim 4 ,
Provided with an operating condition setting means for the user to set operating conditions,
The operating condition acquisition means includes
An apparatus for stabilizing the processing speed of an asynchronous circuit, wherein the operating condition set by the operating condition setting means is acquired. In the asynchronous circuit processing speed stabilizing device according to claim 4 ,
A vehicle inside / outside situation obtaining means for obtaining an inside or outside situation of a vehicle in which the processing speed stabilizing device is mounted;
The operating condition acquisition means includes
The processing speed stabilizing device, wherein the operating condition of the asynchronous circuit is acquired based on an internal or external situation of the vehicle obtained from the vehicle inside / outside situation obtaining means. In the asynchronous circuit processing speed stabilizing device according to any one of claims 1 to 6 ,
Processing speed change condition acquisition means for acquiring a processing speed change condition for changing the processing speed of the asynchronous circuit that is made constant by the processing speed stabilizing device;
A processing speed change control means for changing the processing speed of the asynchronous circuit that is fixed by the processing speed stabilizing device only when the processing speed change condition acquired by the processing speed change condition acquisition means satisfies a predetermined condition; ,
An apparatus for stabilizing the processing speed of an asynchronous circuit, comprising: In the asynchronous circuit processing speed stabilizing device according to claim 7 ,
A processing speed change condition setting means for a user to set a processing speed change condition is provided,
The processing speed change condition acquisition means includes
A processing speed stabilizing device for an asynchronous circuit, wherein the processing speed changing condition for an asynchronous circuit that is made constant by the processing speed stabilization processing device set by the processing speed changing condition setting means is acquired. In the asynchronous circuit processing speed stabilizing device according to claim 7 ,
A vehicle inside / outside situation obtaining means for obtaining an inside or outside situation of a vehicle in which the processing speed stabilizing device is mounted;
The processing speed change condition acquisition means includes
The processing speed stabilizing device, wherein the processing speed changing condition of the processing speed stabilizing device is acquired based on an internal or external situation of the vehicle acquired from the vehicle internal / external status acquisition means. In the asynchronous circuit processing speed stabilizing device according to any one of claims 1 to 9 ,
The performed based on the number of comparison times between the target pulse number, the processing frequency change condition acquiring means for acquiring a processing frequency change condition for changing the frequency of the supply voltage setting to the asynchronous circuit according to said voltage adjustment means,
Processing frequency changing means for changing the frequency of the supply voltage to the asynchronous circuit by the voltage adjusting means based on the processing frequency changing condition acquired by the processing frequency changing condition acquiring means;
An apparatus for stabilizing the processing speed of an asynchronous circuit, comprising: In the asynchronous circuit processing speed stabilizing device according to claim 10 ,
A processing frequency change condition setting means for the user to set a processing frequency change condition is provided,
The processing frequency change condition acquisition means includes
A processing speed stabilizing device for an asynchronous circuit, wherein the processing frequency changing condition of the processing speed stabilizing processing device set by the processing frequency changing condition setting means is acquired. In the asynchronous circuit processing speed stabilizing device according to claim 10 ,
A vehicle inside / outside situation obtaining means for obtaining an inside or outside situation of a vehicle in which the processing speed stabilizing device is mounted;
The processing frequency change condition acquisition means includes
The processing speed stabilizing device, wherein the processing frequency changing condition of the processing speed stabilizing device is acquired based on an internal or external situation of the vehicle acquired from the vehicle internal / external status acquisition means. An in-vehicle electronic device comprising the asynchronous circuit processing speed stabilizing device according to any one of claims 1 to 12 .

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