JPH09120323A - Method and device for power source control and electronic equipment - Google Patents

Abstract

PROBLEM TO BE SOLVED: To control fine power consumption reduction in conformity with the use state of the equipment. SOLUTION: The tilt of the electronic equipment is detected by an acceleration sensor 101 and a tilt detection part 102 and the detection result is outputted to a decision part 105. Further, the sight direction of the electronic equipment is detected by a CCD camera 104 and a sight direction detection part 103 and the detection result is outputted to the decision part 105. The decision part 105 outputs a signal making a power-off request to a CPU 106 when deciding that the detected tilt is larger than a specific angle and the sight is not directed to the electronic equipment. The CPU 106 once receiving this request controls a power source control part 110 to turn off a back light 111, thereby reducing the power consumption. When the tilt of the electronic equipment becomes less than the specific angle, control is so performed that the back light 111 is turned on.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a power supply control device and method, and an electronic device equipped with the power supply control device.

[0002]

2. Description of the Related Art Conventionally, portable electronic devices (hereinafter referred to as portable electronic devices) are driven by a battery when used while being carried. By the way, in the current battery performance, it is possible to use the battery for several hours continuously, which is very inconvenient for the user. Therefore, in order to enable driving for a long time, the power supply state of the electronic device is controlled to reduce the power consumption. For example, when no input is made for a certain period of time, the backlight of the liquid crystal display of the electronic device is turned off, or a transition to a low power consumption mode called sleep mode is performed to achieve low power consumption. doing.

[0003]

In the above-mentioned conventional example, the user generally sets a desired transition time until the backlight is turned off or the transition to the low power consumption mode is made. . However, many users continue to use the electronic device in the same state once the setting is made. That is, detailed switching of modes or setting of the transition time is not performed according to the usage situation. Further, the transition time is often set to be long, and power consumption cannot be effectively reduced. Therefore, for long-term use of electronic devices, there is a demand for finer control for lower power consumption that can be performed without disturbing the user.

The present invention has been made in view of the above-mentioned prior art, and provides a power supply control device and its method, and an electronic device capable of controlling the reduction of power consumption in accordance with the usage status of the device. The purpose is to do.

[0005]

The power supply control device of the present invention which achieves the above object has the following configuration. That is,
Consumption based on the first detection means for detecting the inclination of the device, the second detection means for detecting whether or not the device is in use, and the detection results by the first detection means and the second detection means A determining unit that determines whether to control the power reduction and a control unit that reduces the power consumption based on the determination result by the determining unit are provided.

Preferably, the second detecting means is
It is detected that the device is in use by detecting the direction of the user's line of sight. This is because, since the user's line-of-sight direction is detected, for example, it can be determined whether or not the user is paying attention to the device, and it is possible to make a determination according to the actual usage situation.

Further, preferably, in the determining means, the inclination of the device detected by the first detecting means is equal to or more than a predetermined angle, and the device is in an unused state by the second detecting means. When it is detected, it is determined to perform control of power consumption reduction.

Further, preferably, the control means controls the turning on and off of the backlight of the display screen. By turning off the backlight, which consumes a large amount of power, it is possible to effectively reduce power consumption.

Further, preferably, the control means saves the data stored in a memory requiring a refresh operation to a non-volatile memory which does not require the refresh operation and refreshes the memory requiring the refresh operation. To stop. This is because power consumption can be reduced by stopping the refresh operation.

[0010]

Preferred embodiments of the present invention will be described below with reference to the accompanying drawings.

[First Embodiment] FIG. 1 is a block diagram showing a hardware configuration of an electronic apparatus according to the first embodiment. In FIG. 1, 101 is an acceleration sensor for detecting the movement of the electronic device, and 102 is a tilt detection unit that receives a signal from the sensor 101 and detects in which direction and at which angle the electronic device is tilted. . Reference numeral 103 denotes a line-of-sight direction detection unit that captures an image from the CCD camera 104 and detects whether or not the user's line of sight is facing the device. The line-of-sight direction detection unit 103 captures an image from the CCD camera 104 at regular intervals and extracts the contour of the user's face and the positions of both eyes from the image. Note that there is a known method for this technique, and therefore its description is omitted here.

Reference numeral 105 denotes a determination unit that receives signals from the inclination detection unit 102 and the line-of-sight direction detection unit 103 and determines the power supply control. Reference numeral 106 is a CPU that controls the entire electronic device, 107 is a display control unit that controls the display, and 108 is a display memory that stores information to be displayed on the display screen. Reference numeral 109 denotes a display suitable for a portable electronic device such as a liquid crystal display (LCD), 110 denotes a power supply control unit that receives a signal from the determination unit 105 and controls lighting of the backlight 111, 11
Reference numeral 1 is a backlight for the display display 109.

Reference numeral 112 denotes a RAM, which provides a work area when the CPU 106 executes various controls. Also,
A ROM 113 stores various control programs executed by the CPU 106. It should be noted that the control program executed by the CPU 106 is read from a memory card (not shown) or the like.
It may be configured to be loaded into the AM 112 and executed by the CPU 106.

Next, the power supply control operation of the electronic apparatus of the first embodiment having the configuration shown in FIG. 1 will be described.

FIG. 2 is a flow chart showing the power supply control procedure in the first embodiment. In the flowchart of FIG. 2, the processes by the determination unit 105, the CPU 106, and the power supply control unit 110 are shown as a series of processes. Note that CP
It is assumed that the control program for realizing the control shown in this flowchart in U106 is stored in the ROM 113. Further, in FIG. 1, the CPU 106 and the determination unit 105 are separately configured, but it is obvious that both configurations may be realized by one CPU.

Now, it is assumed that the acceleration sensor 101 detects the movement of the electronic device and sends a signal to the tilt detecting section 102. The tilt detection unit 102 detects from the signal which direction the electronic device is tilted in which direction, and sends the detection result to the determination unit 105. There is a known method for detecting which direction and which angle is tilted, and the description thereof is omitted here because it is not a characteristic configuration of the present embodiment.

In step S201, the determination unit 105
When receives a tilt detection signal from the tilt detection unit 102, the process proceeds to step S202. In step S202, the usage state of the electronic device is determined based on the detection result from the line-of-sight direction detection unit 103.

The usage status of the electronic device is determined as follows. Now, from the image captured from the CCD camera 104, the contour of the user's face and the positions of both eyes are
It is assumed that the data can be extracted as shown in FIG. Here, 701 is the outline of the extracted face, and 702 is the extracted both eyes. Further, A and B are the distances between the left and right eyeball positions and the extracted face contour, respectively. In such an eyeball position extraction state, the line-of-sight direction detection unit 103 (1) if A ≧ C and B ≧ C, the user's line-of-sight direction is toward the electronic device, and (2) if other than (1) It is determined that the user's line of sight is not facing the device. Here, C is a predetermined constant value, and is a value that takes into consideration that the electronic device is tilted to some extent when the usage state is determined. The reason is as follows. Since the tilt detection signal is sent when determining the usage state, the relative tilt between the electronic device and the user has already occurred. Therefore, when setting the value of C, if the value of C is increased,
Even if the value of the relative inclination is small, there is a high possibility that the user is determined not to face the device. As described above, even if the user intends to face the device, there is a high possibility that the user is determined not to face the device. Therefore, the value of C is determined in consideration of such a situation.

When it is determined that the line-of-sight direction is directed to the electronic device, the line-of-sight direction detection unit 103 sends a signal indicating the in-use state of the electronic device to the determination unit 105, and when it is determined that the line-of-sight direction is not directed, The determination unit 105 determines the signal indicating the unused state.
Send to Here, when the contour of the face cannot be extracted, it is determined that the user is not in front of the device, and a signal indicating the non-use state of the electronic device is sent to the determination unit 105.

When the determination unit 105 receives a signal indicating that the electronic device is not in use from the line-of-sight direction detection unit 103, the determination unit 105 determines whether or not power supply control is performed based on the tilt detection signal (step S203). The judgment is performed by the following method.

First, it is judged whether or not the tilt detection signal is continuously sent for a fixed time, and if it is not sent, the control is not performed. The determination based on the tilt detection signal is made only when the data is continuously sent for a certain time or longer.

The tilt detection signal is sent in polar coordinates (r, θ) (see FIG. 3). Here, θ represents the direction of inclination, and r represents the magnitude of the inclination. The determination unit 105 determines whether to perform power supply control using this tilt detection signal. Here, the conditions used by the determination unit 105 are: condition 1: power ON control if r ≦ a, condition 2: power OFF control if r> a. Here, in the determination in step S203, the magnitude of the tilt angle (regardless of the direction) continues for a certain time or more (for example, over a predetermined number of times of sampling).
When it is detected that the inclination is larger than a, it is determined that the power supply control is performed.

The determination unit 105 sends a power OFF control request signal to the CPU 106 when the condition 2 is satisfied. That is, the process proceeds from step S203 to step S204, and the power OFF control request signal is output to the CPU 106. CP
U106 receives the power OFF signal and instructs the power control unit 110 to turn off the power. Upon receiving this instruction, the power supply control unit 110 controls the power supply of the electronic device. Here, the backlight is turned off (step S204).

Further, the tilt detecting section 102 continues to detect the tilt of the electronic device, and when the judging section 105 satisfies the above condition 1 (step S205), the judgment signal (power ON control signal) is sent to the CPU 106. Send to. CPU1
06 instructs the power supply control unit 110 to turn on the power supply. The power supply control unit 110 receives this signal and turns on the backlight again (step S206).

FIG. 4 is a diagram showing an example of the external appearance of the electronic apparatus of this embodiment. In the figure, 401 is an electronic device main body, 402 is an input / output unit in which a display unit and a digitizer are integrated, 403 is an input pen for inputting to the digitizer, and 404 is a pen holder for storing the input pen. . In addition, a CCD is provided in a predetermined portion of the electronic device 401.
The camera 104 is attached.

With the above arrangement, the backlight is turned off when the user does not face the electronic device and the electronic device is tilted at the predetermined angle or more continuously for a certain time or longer. You can do it. Therefore, there is an effect that the power consumption can be reduced according to the usage state of the electronic device and the electronic device can be driven for a long time without the user being aware of it.

[Second Embodiment] In the first embodiment, the power supply control operation of the electronic device is performed by the backlight 1 of the display screen.
Although the control for 11 is made, it is also possible to make this another operation. In the second embodiment, an example in which the display memory is the control target is shown.

The operation flowchart of FIG. 5 and FIG. 6 will be described below.
Differences from the first embodiment will be described with reference to the hardware configuration block diagram.

FIG. 6 is a block diagram showing the hardware configuration of the electronic device of the second embodiment. In the figure, the same components as those in FIG. 1 are designated by the same reference numerals as those in FIG. 1, and detailed description thereof will be omitted. 601 is a flash memory.

When the power OFF control is instructed in step S203, that is, when the condition 2 is satisfied, the backlight is turned off in step S204, and the process proceeds to step S501. In step S501, the contents of the display memory 108 are transferred to the flash memory 601. The display memory is usually a DRAM (Dynamic Random A) that requires a refresh operation at regular intervals.
access memory), the flash memory does not require a refresh operation, and since it is a non-volatile memory, its contents are not lost even when the power is turned off.

Therefore, in step S502, the refresh operation of the display memory 108 is stopped. Further, in step S503, power supply to the display control unit 107 is also stopped.

Subsequently, in step S205, when the condition 1 is satisfied, first, the power supply to the display control unit 107 is restarted (step S504), and the flash memory 60.
1 is transferred to the display memory 108 (step S
505). Next, the refresh operation of the display memory 108 is restored (step S506). Finally, the backlight is turned on (step S206) and the display is restarted.

With the above structure, in addition to the effect of reducing the power consumption, the display data can be protected when the device is tilted. Therefore, even if the device is tilted due to falling, the display data is saved to the flash memory, and the display data can be prevented from crashing. Of course, data other than the display data stored in the DRAM may be saved in the flash memory.

As described above, according to the above-described embodiment, it is possible to more finely save the power consumption as compared with the conventional one, so that the operating time of the portable electronic device can be lengthened. There is an effect that can be done. Moreover, since the power consumption is automatically reduced by detecting the usage state of the electronic device, the user does not need to consider switching to the low power consumption mode or the like, and the user's convenience can be improved. It also has an effect.

Obviously, it may be used in combination with a conventional control configuration that automatically controls the power supply when an input operation or the like is not performed for a certain period of time. In this case, for example, when carrying the electronic device in a pocket of clothes, etc.,
Since the movement of the device is detected by the acceleration sensor, quick power supply control according to the above embodiment is executed. Also,
When the electronic device is left on the desk, the motion of the device is not detected, but power saving can be achieved by the conventional power supply control.

The present invention may be applied to either a system composed of a plurality of devices or an apparatus composed of a single device.

Further, an object of the present invention is to supply a storage medium storing a program code of software for realizing the functions of the above-described embodiments to the device, and the computer (or CPU or MPU) of the device stores the storage medium in the storage medium. Needless to say, this can be achieved by reading and executing the stored program code.

[0038]

As described above, according to the present invention,
It is possible to control the transition to the low power consumption mode according to the usage status of the device.

[0039]

[Brief description of the drawings]

FIG. 1 is a block diagram showing a hardware configuration of an electronic device according to a first embodiment.

FIG. 2 is a flowchart showing a power supply control procedure in the first embodiment.

FIG. 3 is a diagram illustrating a form of a tilt detection signal in the present embodiment.

FIG. 4 is a diagram showing an example of an external appearance of the electronic device of the present embodiment.

FIG. 5 is a flowchart illustrating an operation procedure of the electronic device according to the second embodiment.

FIG. 6 is a block diagram showing a hardware configuration of an electronic device according to a second embodiment.

FIG. 7 is a diagram illustrating a method of detecting a user's gaze direction in the present embodiment.

[Explanation of symbols]

 101 Acceleration Sensor 102 Tilt Detection Unit 103 User's Eye Direction Detection Unit 104 CCD Camera 105 Judgment Unit 106 CPU 107 Display Control Unit 108 Display Memory 109 Display Display 110 Power Supply Control Unit 111 Backlight 112 RAM

Claims (11)

[Claims] 1. A first detection means for detecting an inclination of a device, a second detection means for detecting whether or not the device is in use, and a detection by the first detection means and a second detection means. A power supply control characterized by comprising: a determining unit that determines whether or not to perform power consumption reduction control based on the result; and a control unit that executes low power consumption based on the determination result by the determination unit. apparatus. 2. The power supply control device according to claim 1, wherein the second detecting means detects that the device is in use by detecting the line-of-sight direction of the user. 3. The deciding means has an inclination of the device detected by the first detecting means of a predetermined angle or more,
The power supply control device according to claim 1, wherein when the second detection unit detects that the device is in an unused state, it is determined to perform control for reducing power consumption. 4. The control means controls the turning on and off of a backlight of a display screen.
The power supply control device according to. 5. The control means saves the data stored in a memory requiring a refresh operation to a non-volatile memory that does not require the refresh operation, and stops the refresh operation for the memory requiring the refresh operation. The power supply control device according to claim 1, wherein 6. A first detection step of detecting an inclination of a device, a second detection step of detecting whether or not the device is in use, and a detection by the first detection step and a second detection step. A power supply control comprising: a determination step of determining whether or not to perform power consumption reduction control based on the result, and a control step of executing low power consumption based on the determination result of the determination step. Method. 7. The power supply control method according to claim 6, wherein the second detecting step detects that the device is in use by detecting the direction of the line of sight of the user. 8. In the determining step, the inclination of the device detected in the first detecting step is equal to or more than a predetermined angle,
The power supply control method according to claim 6, wherein when the second detection step detects that the device is in an unused state, it is determined to perform control for reducing power consumption. 9. The control step controls the turning on and off of the backlight of the display screen.
The power supply control method described in. 10. The control step saves data stored in a memory requiring a refresh operation to a non-volatile memory that does not require the refresh operation, and stops the refresh operation for the memory requiring the refresh operation. The power supply control method according to claim 6, wherein: 11. An electronic device comprising the power supply control device according to claim 1. Description: