JPH07302138A - Electronic equipment and its power control method - Google Patents

Abstract

PURPOSE:To provide an electronic equipment and its power control method which stores the history information on the accesses given to the devices for each application and then carries out a power down function most properly in response to each application and device. CONSTITUTION:An electronic equipment which carries out plural applications stores the access time intervals in an access time interval table 4 to have an access to each device for each application. Then a calculation/decision part 2 predicts the time when the corresponding application has the next access to the relevant device based on the access time interval stored in the table 4 when the application had an access to the device. A device control part 1 decides whether or not the device should be set in a low power consumption mode based on the predicted access time. Based on this deciding result, the corresponding device is operated in a low power consumption mode.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an electronic device capable of executing a plurality of applications, accessing each device by each application, and shifting to a low power consumption mode when access to each device ends The present invention relates to a power supply control method.

[0002]

2. Description of the Related Art In electronic equipment having a built-in microcomputer or the like, so-called power-down, in which the power is cut off or the power is turned off in a low power consumption mode (mode) when the memory or the display is not accessed for a predetermined time. There are devices with functions.

[0003]

However, in the above-described conventional power-down function, regardless of which application is being executed, the power-down state is entered if there is no access for a predetermined time. Even if the device is unnecessary for the device, it will not enter the power-down mode unless the device waits for a predetermined time. Therefore, the power consumption and the delay time until then were wasted.

Further, as will be described later with reference to FIG. 4, depending on the device, the power consumption may be higher than the normal state when shifting to the low power consumption mode or when shifting from the low power consumption to the high power consumption mode. The power may increase. In this case, after the access to a device is finished,
When a predetermined time has elapsed, the low power consumption mode is entered, and immediately after that, access is started and the original high power consumption mode is entered. As a result, the low power consumption mode is not switched and the high power consumption mode is kept. In this case, the total power consumption decreases.

The present invention has been made in view of the above conventional example. For each application, history information of access to each device is stored, and a power-down function is optimally executed according to the application and the device. An object is to provide an electronic device and a power supply control method in the device.

Another object of the present invention is to provide an electronic device which can reduce power consumption when there is no access and a power supply control method in the device.

Another object of the present invention is to predict the access time of each device for each application, determine whether to execute the power down function based on the predicted time, and execute the power down function. Another object of the present invention is to provide an electronic device and a power supply control method for the device.

[0008]

In order to achieve the above object, the electronic equipment of the present invention has the following configuration. That is, an electronic device that executes a plurality of applications, a storage unit that stores an access time interval for accessing each device for each application, and an access stored in the storage unit when the application finishes accessing the device. Prediction means for predicting a time at which the application next accesses the device based on a time interval, and judgment means for judging whether or not to set the device in the low power consumption mode based on the prediction by the prediction means. Low power consumption operating means for operating the corresponding device in the low power consumption mode based on the determination by the determination means.

In order to achieve the above object, the power supply control method for electronic equipment of the present invention comprises the following steps.
That is, a power control method in an electronic device that executes a plurality of applications, wherein a step of storing an access time interval for accessing each device for each application, and a stored access time at the end of device access by the application A step of predicting a time when the application next accesses the device based on the interval, a step of judging whether to set the device to the low power consumption mode based on the prediction, and a step of judging based on the judgment And operating the corresponding device in the low power consumption mode.

[0010]

In the above structure, the access time interval for accessing each device for each application is stored,
When the application finishes accessing the device, the time at which the application next accesses the device is predicted based on the stored access time interval. Based on the predicted time, it is determined whether to set the device in the low power consumption mode, and based on the determination, the corresponding device is operated to operate in the low power consumption mode.

[0011]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT A preferred embodiment of the present invention will now be described in detail with reference to the accompanying drawings.

[First Embodiment] FIG. 2 is a block diagram showing a hardware configuration of an electronic apparatus according to the present embodiment.

In FIG. 2, reference numeral 11 is a CPU, which is a main memory 2.
The entire device is controlled in accordance with the control program stored in 4. An input unit (input device) 12 is a pointing device such as a keyboard or a mouse.
An input control circuit 13 outputs various data input from the input unit 1 to the CPU 11. 14 is a liquid crystal or CRT
The data sent under the control of the CPU 11 is displayed under the control of the display control circuit 15 on the display unit (display device) such as. A ROM 16 stores various data such as font data. 17 is a RAM,
It is used as a work area for temporarily storing various data by the CPU 11. Reference numeral 18 denotes a memory control circuit, which performs read / write control on the ROM 16 and RAM 17 and exchanges data with the hard disk controller 20. 19 is a hard disk drive unit (HDD), 20 is a hard disk (HDD) 1
9 is a hard disk control circuit that controls writing of data to the hard disk 9 and reading of data from the hard disk 19. A communication unit (communication device) 21 includes a communication control circuit 2
Data is exchanged between the CPU 11 and the communication line via the communication line 2. Reference numeral 23 is a power supply for supplying electric power to the entire device including the above-mentioned units. A main memory 24 is a control program (see FIG. 7) executed by the CPU 11.
And the flow chart of FIG. 8)
It is used as a work area for various control operations by U11. Reference numeral 25 denotes a timer built in the CPU 11, which starts time counting when the power of this device is turned on, and measures the elapsed time and the like.

Under the control of each control circuit, each of the above-mentioned units can make a transition between two states of mode H (high power consumption mode) and mode L (low power consumption mode). The mode is in the mode H while each part is in use, and is in the mode L when not in use. However, from mode H to L,
Alternatively, it takes some time to transit from the mode L to the mode H. In addition, in the transitional state during this transition, there are devices that require more power than in the steady state. Therefore, when it is necessary to transit to mode H immediately after transiting to mode L, as a result, It is determined that the power consumption will be lower if it is left as it is, and the state transition is not executed.

Therefore, in the electronic device of this embodiment, the mode H
When there is no access for a predetermined time in this state, it is determined whether or not the state transition to the mode L is performed.

Next, the state transition in the present embodiment will be described with reference to an example of the state transition.

FIG. 3 is a timing chart showing an example of state transition. When a trigger indicating that the device has been used is generated at time t1, the state transition to mode L is started. As a result, after a transition from the mode H to the mode L, the steady state of the mode L is reached at time t2. Further, at time t3, the transition to the mode H is started by the use trigger due to the access of the part. After the transitional state due to the transition from mode L to mode H, the steady state of mode H is reached at time t4.

Here, the steady state of mode L, the steady state of mode H, the transient state from mode H to L, and the mode L
Power consumption in each of the transition states from H to H is p1, p2, p3, and p4, respectively.

Time t1 when the above-mentioned state transition is performed
The power consumption w1 from to t4 is given by the following equation.

W1 = p3 × (t2-t1) + p1 × (t3-t2) + p4 × (t4-t3) Equation (1) When no transition is performed (shown by the broken line in FIG. 3)
Power consumption amount w2 from time t1 to time t4 is given by the following equation.

W2 = p2 × (t4−t1) Equation (2) If the above two equations are calculated, it is determined whether or not the transition is performed.
You can see which power is large. Each value of the power consumption p1, p2, p3, p4 and the time (t2-t1) and (t4-t3) required for the state transition in each state described above is specified for each device (each part).

When an end trigger is generated at time t1, the time t3 is predicted at the time t1, and whether to transit to the mode L depending on which of the above two equations (1) and (2) is larger. Decide. Then, if the time t3 at which the usage trigger is applied satisfies the following expression (3), it is determined that the power consumption is smaller when the mode is changed to the mode L after the end trigger is generated in the mode H, and if the following expression (3 If the condition (1) is not satisfied, it is determined that the power consumption is smaller if the mode is not transited to the mode L even if the end trigger is generated in the mode H.

(T3-t2) × (p2-p1)> (p3-p2) × (t2-
From t1) + (p4-p2) × (t4-t3) t3> t2 + {(p3-p2) × (t2-t1) + (p4-p2) × (t4-t3)} / (p2-p1)… Expression (3) As described above, in this embodiment, at the time of time t1, the time
By predicting t3, it is determined whether to transit from mode H to mode L.

FIG. 4 is a diagram for explaining the conventional state transition. In this case, the state transition from the mode H to the mode L does not occur immediately at the time when the end trigger occurs, and the time
After (t1'-t1) has passed, a state transition from mode H to mode L has occurred. Then, at time (t2'-t1 '), a state transition from H to L occurs, and at time t3, a use trigger occurs and a state transition from mode H to mode L occurs.

Comparing FIG. 3 and FIG. 4, the time (t4-t1) from the generation of the end trigger to the generation of the use trigger in mode H is the same, but the power consumption thereof is the same. It can be seen that the conventional method has several stages more than the present embodiment.

Next, a case where such an idea is applied to a multitask system will be described. Now, the application is once every a seconds, and the application B is once every b seconds.
Assuming that the application C accesses a device at a rate of once every c seconds, the device will perform {(1 / a) + (1 / b) + (1 / c)} times per second. Accessed at a rate. In other words, 1 / {(1 / a)
+ (1 / b) + (1 / c)} is accessed once per second.

Therefore, the time t3 at which the use trigger occurs can be predicted as t3 = t1 + 1 / {(1 / a) + (1 / b) + (1 / c)} equation (4), By substituting this time t3 into the above equation (3), it is determined whether or not to transit to the mode L.

As shown in FIG. 5, a time interval in which each application accesses each device such as the input unit 12, the display unit 14, the ROM 16, the RAM 17, the hard disk 19 and the communication unit 21 (the next access is made after the last access). Is stored in a table format. The values of a, b, c, etc. described above are determined according to these access time intervals. Each value in this table is updated by the following method each time each application (AE) actually accesses each device described above.

FIG. 6 shows the time when the last access to each device in each application was completed. In FIG. 6, it is represented by an absolute time (second) according to the elapsed time (second) after the use of this system. In the following description, these times will be similarly represented.

Now, when a certain application accesses a certain device, a value obtained by subtracting the time shown in FIG. 6 (the time when the previous access is finished) from the current time is the time interval until the current access. However, in order to predict the time interval until the next access, it is considered that a more appropriate access time interval can be obtained by referring to the past time interval rather than referring only to the time interval only this time. To be Therefore, the time interval until an application accesses a certain device (the value obtained by subtracting the time shown in FIG. 6 from the current time), and the past access time interval to the device given by the application (the value shown in FIG. 5)
And the new access time interval as shown in FIG.
Update the table value corresponding to the application and device shown in.

When an application finishes accessing a device, the time value for the device of the corresponding application in FIG. 6 is updated to the current time at that time.

Based on the above functions, a functional block diagram of this embodiment is shown in FIG.

Reference numeral 1 denotes a device control section, which corresponds to the control circuits 13, 15, 18, 20 and 22 of each section in FIG. Reference numeral 2 is a calculation / determination unit, which is the CP in FIG.
It corresponds to U11 and the main memory 24. The calculation / judgment unit 2 calculates each of the above-mentioned formulas, and judges whether to make a state transition from the mode H to the mode L according to the calculation result. A time counting unit 3 corresponds to, for example, the timer 25 in FIG. 2 and measures the elapsed time (absolute time) after the use of the electronic device of this embodiment is started. An access time interval table 4 stores the access time interval at which each application accesses each unit (each device) in the format shown in FIG. 5, for example. An access time table 5 stores the absolute time when the last access to each device of each application is completed, as shown in FIG. Access time interval table 4 and access time table 5
The item is added each time a new application is executed. Then, when the execution of the application is completed, the time information is stored in the access time table 5, but the item of the access time table 5 corresponding to the application is not referred to in the calculation of Expression (4). Then, when the application is re-executed, the current time counted by the time counting section 3 is stored in the access time table 5 corresponding to the application. The tables 4 and 5 may be stored in the main memory 24 or the ROM 16.

The operation when a certain application accesses a certain device (for example, the HDD 19) in the present embodiment will be described using specific numerical values with reference to the flowchart of FIG. The control program for executing this process is stored in the main memory 24, and is executed by the CPU 11 executing the process according to this control program.

Now, for example, in step S1, when the absolute time is 3600 seconds, the application A is the HDD
Suppose you have accessed 19. Then, the process proceeds to step S2, and the end time when the application accessed the HDD 19 last time is read from the access time table 5 shown in FIG. For example, in the case of the HDD 19, the mode H corresponds to the rotating state of the motor, and the mode L corresponds to the stopped state of the motor. In FIG. 6, since the last access time is 3592 seconds, in this case, step S3
In, the elapsed time from the end of the previous access by the application A to the present (3600-359
Find from 2). This shows that it is 8 seconds.
Then, the process proceeds to step S4, the average of the current access time interval (8 seconds) and the past access time interval (value stored in the table of FIG. 5, 20 seconds) is calculated, and then the process proceeds to step S5. Access time interval table 5
Set to.

That is, the HDD 1 by the application A
The past access time interval to 9 is, for example, 20 from FIG.
Since it is seconds, the average of 8 seconds described above and 20 seconds obtained from FIG. 5 is obtained, and the average value "14 seconds" is determined as a new access time interval. Based on the determined value, the HDD 19 by the application A shown in FIG.
Access time table value is "20" seconds to "14"
Updated in seconds.

The operation when the access to the device by a certain application is completed will be described with reference to the flowchart of FIG. This processing is also executed by the CPU 11, and the control program for executing this processing is stored in the main memory 24.

If it is determined in step S11 that the access to the HDD 19 is completed when the current time is 3602 seconds, the process proceeds to step S12, and the corresponding time in the access end time table 5 is updated. Specifically, the time when the access of the HDD 19 by the application A of the table value of FIG. 6 is finished is changed from “3592” to “360.
The time t3 is updated to 2 ″ seconds. Next, in step S13, the time t3 is obtained by the following equation using the above equation (4).

T3 = t1 + 1 / {(1 / a) + (1 / b) + (1 / c) + (1 / d) + (1 / e)} ... It can be obtained by the equation (5). Here, t1 is 3602 seconds.

As mentioned above, a is "20" to "14".
Has been updated to. Further, each of b to e is b = 30, c = 30, d = 300, and e = 1800 from FIG. Therefore, t3 is calculated to be about 3609 seconds. As a result, t3 = 3609 is substituted into the above equation (3),
When the expression (3) is satisfied, the HDD 19 is transited to the mode L, and when it is not satisfied, the transition to the mode L is not performed.

Conventionally, as shown in FIG. 4 described above, a general method is to wait from a device end trigger (t1) to a certain time (t1 '), and then transition to mode L if no usage trigger arrives. is there.

On the other hand, as in this embodiment, by changing to the mode L at time t1, (p2-p1) * (t1'-t
The power consumption of 1) can be saved.

Equation (4) shows that the value of t3 decreases as more applications with shorter access intervals are executed at the same time. Therefore, in such a case, the number of cases in which the expression (3) is satisfied is reduced, and as a result, it becomes difficult to transit to the mode L. Therefore, there is an effect of suppressing the influence of power consumption and delay time in the transitional transition state.

Further, in the present embodiment, after the access to a certain device is completed, it is judged whether or not to shift to the low power consumption mode without waiting for the elapse of a predetermined time, so that the low power consumption can be performed more efficiently. The power down function can be realized by setting the power mode.

[Second Embodiment] In the second embodiment, a history of when the next access is made after the access to a certain device is completed. The power consumption w1 (t3) is calculated by the equation (1) at each time t3 in the past n accesses, and the expected values w3 of the power consumption are obtained by averaging them.

W3 = {Σ ((p3 × (t2-t1) + p1 × (t3-t2) + p4 × (t4-t3))} / n Equation (6) where Σ is n It represents the sum of the power consumption for each batch.

Here, the above equations (2) and (6) are calculated, and the magnitudes of these are compared to determine whether or not the mode L is to be entered. And w3 <w2
If so, it transitions, otherwise it does not transition.

In the above equation (6), p1, p3, p
Since the values of 4, (t2-t1) and (t4-t3) are specified for each device, (t3-t2) when each device is accessed corresponding to each application as shown in FIG. A table for storing the value of (time in mode L) is provided.

In this way, the expected value of the power consumption is compared when the state transition from the mode H to the mode L is performed and when it is not performed, and it is determined whether or not the transition is made based on the magnitude of these values. This has the effect of increasing the possibility of selecting a transition that reduces power consumption.

[Third Embodiment] Hard Disk (HDD)
In the case of 19, the file is generally accessed as a file in many cases. Further, it may be accessed for the purpose of saving memory such as virtual memory. Therefore, the access time interval changes depending on whether the file is open or the virtual memory is turned on. FIG. 10 shows an example of access time intervals in each state.

In FIG. 10, the time interval for accessing the HDD 19 is off (O) when the virtual memory is on.
It can be seen that the time interval is shorter than that in the FF) state, and the time interval when the file is opened is much shorter than when it is closed.

By using FIG. 10 as the time interval table, it is determined whether or not the state transition is performed as in the first embodiment. Other devices are often handled as files, and the same applies.

According to this embodiment, the access of the device can be predicted from the time interval not only for each application but also for each system state.

[Fourth Embodiment] Referring to FIG.
If the delay time required for the state transition from when the use trigger is input at t3 until the device is actually available at time t4 is long, it causes the user to wait longer, which adversely affects the operability.

Therefore, as shown in the timing chart of FIG. 11, the virtual power consumption is added to the actual power consumption p4 in the transient state from the mode L to the mode H, and it is set to p5. Then, the following equation (7) is used instead of the above equation (3) to determine whether or not the transition to the mode L is made.

T3> t2 + {(p3-p2) × (t2-t1) + (p5-p2) × (t4-t3)} / (p2-p1) Equation (7) Since p5> p4, , Equation (7) is less likely to satisfy the inequality, and transition to mode L is less likely.

As described above, according to the fourth embodiment, even if the power consumption is a little large, it is effective when the transition from the mode L to the mode H is required at high speed.

By adjusting the value of p5, the trade-off between the power consumption and the state transition speed from mode L to mode H can be adjusted.

The present invention may be applied to a system composed of a plurality of devices or an apparatus composed of a single device. The present invention can also be applied to the case where it is achieved by supplying a program for implementing the present invention to a system or an apparatus.

As described above, according to this embodiment, the time for each application program to access the device next after the access to the device is predicted is predicted, and the power down function is based on the prediction. By determining whether or not to execute, it is possible to perform the optimum power down with the power consumption suppressed.

Further, according to the present embodiment, since unnecessary power down transition processing is reduced, it is possible to suppress power consumption as a whole.

Further, according to this embodiment, after the access to the device is completed, the next access time is predicted and it is determined whether or not the power down is performed. Therefore, there is no access after the access is completed as in the conventional case. There is no need to wait for a predetermined time as it is, and there is an effect that the power-down processing can be executed efficiently.

Further, according to the present embodiment, for each access,
Since the access time interval of each device is updated, it is possible to more accurately predict the next access time and achieve the power down function.

[0064]

As described above, according to the present invention, the history information of access to each device is stored for each application, and the power down function can be optimally executed according to the application and the device. There is.

Further, according to the present invention, there is an effect that the power consumption can be suppressed low when there is no access.

Further, according to the present invention, the access time of each device is predicted for each application, and the power down function is executed by judging whether to execute the power down function based on the predicted time. There is an effect that the optimal low power consumption mode can be set.

[0067]

[Brief description of drawings]

FIG. 1 is a functional block diagram of an electronic device according to an embodiment of the present invention.

FIG. 2 is a block diagram showing a hardware configuration of an electronic device according to an embodiment of the present invention.

FIG. 3 is a timing chart showing the timing of mode transition and the transition of power consumption according to an embodiment of the present invention.

FIG. 4 is a diagram for explaining a conventional mode transition.

FIG. 5 is a diagram showing an example of an access time interval table according to the present embodiment.

FIG. 6 is a diagram showing an example of an access time table according to the present embodiment.

FIG. 7 is a flowchart showing an access time interval table update process during device access according to the first embodiment of this invention.

FIG. 8 is a flowchart showing a process of determining whether or not to enter a mode L at the end of access to the device according to the first embodiment of this invention.

FIG. 9 is a diagram showing an example of a table that stores a history of times when an application A accesses an HDD according to the second embodiment of this invention.

FIG. 10 is a diagram showing an example of a time interval table for accessing an HDD in the third embodiment of the present invention.

FIG. 11 is a diagram illustrating a transition of power consumption in mode transition according to the fourth embodiment of the present invention.

[Explanation of symbols]

 1 Device control unit 2 Calculation / determination unit 3 Time counting unit 4 Access time interval table 5 Access time table 11 CPU 12 Input unit 14 Display unit 17 Hard disk (HDD) 23 Power supply unit 24 Main memory 25 Timer

 ─────────────────────────────────────────────────── ─── Continuation of front page (72) Inventor Takashi Harada 3-30-2 Shimomaruko, Ota-ku, Tokyo Canon Inc. (72) Inventor Eisaku Tatsumi 3-30-2 Shimomaruko, Ota-ku, Tokyo Canon Incorporated (72) Inventor Shinichi Sunagawa 3-30-2 Shimomaruko, Ota-ku, Tokyo Canon Inc. (72) Inventor Ryoji Fukuda 3-30-2 Shimomaruko, Ota-ku, Tokyo Canon Inc. ( 72) Inventor Katsuhiko Nagasaki 3-30-2 Shimomaruko, Ota-ku, Tokyo Canon Inc.

Claims (12)

[Claims] 1. An electronic device that executes a plurality of applications, comprising: storage means for storing access time intervals for accessing each device for each application; and storage in the storage means when an application finishes accessing the device. A prediction unit that predicts a time at which the application will access the device next based on the access time interval, and determines whether to set the device to the low power consumption mode based on the prediction by the prediction unit. Determination means, and low power consumption operating means for operating the corresponding device in a low power consumption mode based on the determination by the determination means,
An electronic device comprising: 2. The electronic device according to claim 1, wherein the device includes at least one of an input unit, a display unit, and an external storage device. 3. A time storage means for storing an end time of access to the device, wherein the storage means is accessed by an end time stored in the time storage means and a time when the device is next accessed. Find the time interval,
The electronic device according to claim 1, wherein the time interval of the storage unit is updated with reference to the time interval stored in the storage unit. 4. The determining means determines a first amount of power saved by the prediction time predicted by the predicting means, a state transition to the low power consumption mode and a low power consumption mode by the next access. Compare the excess second power amount due to the state transition to the more normal state, and set the low power consumption mode when the first power amount is greater than the second power amount. The electronic device according to claim 1, wherein the electronic device is determined. 5. The expected power consumption value until the next access when the low power consumption mode is set based on the predicted time predicted by the predicting means,
Comparing the power consumption until the next access when the low power consumption mode is not set, and determining to set the low power consumption mode when the power consumption is larger than the expected power consumption value. The electronic device according to claim 1, wherein: 6. The electronic device according to claim 1, wherein the storage unit further stores an access time interval according to a state of the device. 7. The electronic device according to claim 4, wherein the determination unit virtually increases the second amount of power to reduce the probability of shifting to the low power consumption mode. 8. A method of controlling power in an electronic device that executes a plurality of applications, comprising: storing an access time interval for accessing each device for each application; and storing the access time interval when the application finishes accessing the device. A step of predicting a time at which the application next accesses the device based on the access time interval, and a step of judging whether to set the device to the low power consumption mode based on the prediction; And a step of operating a corresponding device in a low power consumption mode based on the determination. 9. The power supply control method according to claim 8, wherein the device includes at least one of an input unit, a display unit, and an external storage device. 10. The device further comprises a step of storing an access end time to the device, wherein an access time interval is obtained based on the stored access end time and the time when the device is next accessed, and the stored access is stored. 9. The power supply control method according to claim 8, wherein the access time interval is updated and stored by referring to the time interval. 11. The determining step comprises a first power amount saved by a predicted time, a state transition to the low power consumption mode and a state from the low power consumption mode to a normal state by the next access. And comparing the excess second power amount due to the transition, and determining to set the low power consumption mode when the first power amount is larger than the second power amount. The power supply control method according to claim 8. 12. The determination step includes the expected power consumption value until the next access when the low power consumption mode is set based on the predicted time and the next power consumption value when the low power consumption mode is not set. 9. The power supply control according to claim 8, wherein a power consumption amount up to access is compared, and when the power consumption amount is larger than the expected power consumption value, it is determined to set the low power consumption mode. Method.