electronic devices

Abstract

An electronic device is provided, comprising: a power supply unit (10) and a main body unit (20), wherein the power supply unit (10) converts power supplied from an external power source into a DC voltage of a first voltage value to output the result to the main body unit (20), and when the power supply from the external power source stops, changes the value of the output DC voltage to a second voltage value different from the first voltage value; and when the value of the DC voltage output by the power supply unit (10) changes to the second voltage value, the main body unit (20) performs a predetermined termination process.

Description

Technical Field

[0001] The present invention relates to an electronic device that operates by power supplied from an external alternating current (AC) power source. Background Technology

[0002] An electronic device is known that operates by power supplied from an AC source (e.g., a residential commercial power supply). Typically, in operating such an electronic device, an external or built-in power supply unit converts the power supplied from the AC power source into direct current (DC) power, and supplies the DC-converted power to the main body of the electronic device. Summary of the Invention

[0003] [Technical Issues]

[0004] Power from an external AC power source to the power supply unit may unexpectedly cease due to power failures or other reasons. In such cases, power from the power supply unit to the main unit of the electronic device will eventually be cut off, making it difficult for the main unit to continue operating. However, there are situations where, for example, it is anticipated that the power accumulated in the power supply unit may be used to perform the termination process of the main unit before the power to the main unit is completely cut off. To achieve this, the power supply unit needs to detect that the power has been cut off and notify the main unit of this event. However, receiving the notification from the power supply unit requires control signal lines for transmitting such notifications.

[0005] The present invention has been made in consideration of the above-described circumstances, and as an object thereof, it provides a method to perform processing based on power cut-off when external power has been cut off, without using control signal lines.

[0006] [Solution to the problem]

[0007] An electronic device according to one aspect of the present invention is an electronic device including a power supply unit and a main unit, wherein the power supply unit includes an output section and a control section, the output section converts power supplied from an external power source into a DC voltage of a first voltage value and outputs the voltage to the main unit, the control section changes the value of the DC voltage output by the output section to a second voltage value different from the first voltage value when the power supply from the external power source is cut off, and the main unit performs a predetermined termination process when the value of the DC voltage output by the power supply unit has been changed to the second voltage value.

[0008] According to one aspect of the present invention, a power supply unit is a power supply unit that provides power to the main body unit of an electronic device. The power supply unit includes an output section and a control section. The output section converts the power supplied from an external power source into a DC voltage of a first voltage value and outputs the voltage to the main body unit of the electronic device. The control section changes the value of the DC voltage output by the output section to a second voltage value that is different from the first voltage value when the power from the external power source is cut off. Attached Figure Description

[0009] Figure 1 This is a configuration block diagram illustrating the configuration of an electronic device according to an embodiment of the present invention.

[0010] Figure 2 This is a timing diagram used to illustrate the details of control performed by an electronic device according to an embodiment of the present invention. Detailed Implementation

[0011] The embodiments of the present invention are described in detail below with reference to the accompanying drawings.

[0012] Figure 1 This is a configuration block diagram illustrating the configuration of an electronic device 1 according to an embodiment of the present invention. The electronic device 1 is, for example, a personal computer or home game console, and includes a power supply unit 10 and a main unit 20. Furthermore, the electronic device 1 is connected to an external power source P via a power cable 30. In this embodiment, the external power source P is AC power, such as a residential commercial power supply.

[0013] The power supply unit 10 includes an AC / DC converter 11 and a control circuit 12.

[0014] AC / DC converter 11 converts AC power input from external power source P via power cable 30 into DC voltage of a predetermined value and outputs the voltage to main unit 20. In the following description, the AC voltage input from external power source P to AC / DC converter 11 is described as input voltage Vi, and the DC voltage output after conversion by AC / DC converter 11 from input voltage Vi is described as output voltage Vo. The output voltage Vo needs to be a voltage that allows main unit 20 to operate. Typically, the magnitude of output voltage Vo is assumed to be set to voltage value V1.

[0015] The control circuit 12 is an integrated circuit or the like, and detects when the power supply from the external power source P has been cut off. For example, there may be a situation where the power supply from the external power source P to the electronic device 1 is accidentally cut off due to a power failure or by the user pulling out the power cable 30. The control circuit 12 monitors the input voltage Vi and thereby detects whether the power supply from the external power source P to the power supply unit 10 has been cut off. The details of the control performed by the control circuit 12 in the case of power cut-off detection will be described later.

[0016] It should be noted that the power supply unit 10 includes a capacitor (not shown) for current smoothing, etc., and that power is accumulated in the capacitor when power is supplied from an external power source P. In the event that power from the external power source P has been disconnected, the power supply unit 10 can supply the power accumulated in the capacitor to the main unit 20. However, the power accumulated in the capacitor is assumed to be insufficient to allow the main unit 20 to operate for an extended period.

[0017] The main unit 20 includes a power supply circuit 21, a system circuit 22, and two resistors R1 and R2.

[0018] The power supply circuit 21 is an integrated circuit or the like, and converts the output voltage Vo from the power supply unit 10 into a voltage according to the specifications of the portion included in the main unit 20, to output the converted voltage. In this embodiment, the power supply circuit 21 reduces the output voltage Vo to the operating voltage Vr and outputs the operating voltage Vr to the system circuit 22. Although not shown here, the power supply circuit 21 may be a power supply circuit 21 that provides the voltage required for the operation of each portion of the main unit 20 other than the system circuit 22. The voltage to be applied to each portion may be the same as or different from the operating voltage Vr. Each portion of the main unit 20, including the system circuit 22, is operated by power supplied from the power supply circuit 21.

[0019] System circuit 22 is an integrated circuit or the like, and operates by power supplied from the operating voltage Vr supplied by power supply circuit 21. Specifically, in this embodiment, when power from external power supply P has been cut off, system circuit 22 performs a predetermined termination process. For example, this termination process could be a process of writing log data indicating the occurrence or shutdown of power cutoff, to stop the operation of the device's units under normal procedures.

[0020] The output voltage Vo from AC / DC converter 11 is gradually reduced by resistors R1 and R2 before being input to system circuit 22. In the following description, the voltage gradually reduced by resistors R1 and R2 and then input to system circuit 22 is described as a decreasing voltage Vd. The value of the decreasing voltage Vd is proportional to the value of the output voltage Vo. In other words, a proportionality constant r, defined according to the respective resistance values ​​of resistors R1 and R2, is established between the output voltage Vo and the decreasing voltage Vd as Vd = r·Vo. System circuit 22 includes an analog-to-digital (AD) converter 22a, and measures the magnitude of the decreasing voltage Vd based on the conversion of the magnitude of the analog value of the decreasing voltage Vd into a digital value by the AD converter 22a. By continuously performing this measurement of the decreasing voltage Vd, system circuit 22 detects changes in the output voltage Vo.

[0021] In the following description, the operation of electronic device 1 when power from external power source P has been cut off will be explained. Upon detecting a power cut-off from external power source P, control circuit 12 outputs a control command to change the magnitude of the output voltage Vo to that of AC / DC converter 11. Specifically, control circuit 12 changes the magnitude of the output voltage Vo of AC / DC converter 11 from voltage value V1 to a voltage value V2 that is different from voltage value V1. Voltage value V2 can be a value less than voltage value V1. However, voltage value V2 needs to be a value that allows power supply circuit 21 to achieve such control by outputting operating voltage Vr based on output voltage Vo. Therefore, voltage value V2 will be a value at least greater than the operating voltage Vr.

[0022] System circuit 22 monitors the value of the drop voltage Vd to detect changes in the output voltage Vo. When the output voltage Vo changes from voltage value V1 to voltage value V2, the value of the drop voltage Vd, which is proportional to the output voltage Vo, changes accordingly. As a specific example, the case of voltage values ​​V1 = 12V, V2 = 10V, and a proportionality constant r of 0.2 will be explained. Upon detecting a power cut-off, control circuit 12 changes the output voltage Vo of AC / DC converter 11 from 12V to 10V. Associated with this change, the drop voltage Vd input to system circuit 22 changes from 2.4V (=12V × 0.2) to 2V (=10V × 0.2). System circuit 22 detects this change in output voltage Vo by comparing the measured value of the drop voltage Vd with a predetermined threshold (e.g., 2.2V).

[0023] When a change in output voltage Vo from voltage value V1 to voltage value V2 is detected, system circuit 22 assumes that the power supply from external power source P to power supply unit 10 has been cut off. As described above, in the case of power cut-off from external power source P, power supply unit 10 intentionally changes the value of its own output voltage Vo, enabling system circuit 22 to detect the power cut-off without establishing a connection between power supply unit 10 and system circuit 22 via control signal lines. Upon detecting a power cut-off, system circuit 22 performs the aforementioned termination process. Note that voltage value V2 needs to be a different magnitude from voltage value V1, sufficient to allow system circuit 22 to recognize the change in drop voltage Vd without any error detection.

[0024] Will use Figure 2 A timing diagram is used to describe the control flow described above. Figure 2The upper part shows the time variation of the input voltage Vi input to the power supply unit 10, the middle part shows the time variation of the output voltage Vo of the power supply unit 10, and the lower part shows the time variation of the operating voltage Vr supplied by the power supply circuit 21 to the system circuit 22.

[0025] Figure 2 The instruction is to cut off power from external power source P at time t1. Triggered by the power cut-off, control circuit 12 changes the output voltage Vo of AC / DC converter 11 from voltage value V1 to voltage value V2. Under normal operation, a certain amount of power accumulates in power supply unit 10, and therefore, even if power from external power source P has been cut off, power supply unit 10 can continue to provide the accumulated power at voltage value V2. The change in the output voltage Vo causes a change in the drop voltage Vd that will be input to system circuit 22, and system circuit 22, having thus detected this change, begins the pre-determined termination process.

[0026] Even after the output voltage Vo has changed from voltage value V1 to voltage value V2, the power supply circuit 21 continues to gradually reduce the output voltage Vo and supplies power of the operating voltage Vr to the system circuit 22, as in the previous process. The system circuit 22 can use the power supplied from the power supply circuit 21 to perform the termination process.

[0027] Subsequently, if the remaining power in power supply unit 10 decreases, the AC / DC converter 11 becomes unable to maintain the output voltage Vo at the voltage value V2, the output voltage Vo drops, and ultimately, the power supply from power supply unit 10 to main unit 20 is cut off. Figure 2 In this context, the output voltage Vo is assumed to decrease further from the voltage value V2 at the timing point t2. Therefore, the system circuit 22 needs to complete the termination process during the period from time t1 to time t2 (i.e., the period during which the power supply unit 10 can continue to supply power to the voltage value V2 using the remaining power).

[0028] Note that if the system circuit 22 detects a further decrease in the output voltage Vo from the voltage value V2 within a predetermined time period, it may perform a different process than the process performed when the output voltage Vo has already changed to the voltage value V2. In this embodiment, the power supply unit 10 is assumed to provide power at voltage value V1 during normal operation and at voltage value V2 when power is cut off from the external power supply P. Therefore, if the output voltage Vo drops further below the voltage value V2 before a predetermined time period has elapsed since the timing of the drop in the output voltage Vo to the voltage value V2, an unexpected abnormality such as a failure of the power supply unit 10 may have occurred. Thus, if it is detected that within a predetermined time period after the detection that the drop in voltage Vd has dropped to a first threshold greater than r·V2, the drop in voltage Vd further decreases below a second threshold less than r·V2, the system circuit 22 may perform a different process than the termination process described above, such as writing log data indicating that an abnormality has occurred.

[0029] As described above, using the electronic device 1 according to this embodiment, when the power supply is cut off from the external power supply P, the power supply unit 10 changes the value of the output voltage Vo and detects the change in the value of the output voltage Vo by the system circuit 22 in the main unit 20, so that processing can be performed according to the power supply cut-off without separately performing the transmission / reception of control signals between the power supply unit 10 and the system circuit 22.

[0030] Note that the embodiments of the present invention are not limited to the embodiments explained above. For example, in the above description, the number of power lines between the power supply unit 10 and the main unit 20 has been assumed to be 1, but the power supply unit 10 may supply power to the main unit 20 via multiple power lines. In this case, the power supply unit 10 provides power to the multiple power lines with different voltage values. In this example, when a power cut-off is detected, the control circuit 12 of the power supply unit 10 changes the magnitude of the output voltage to a predetermined value so that the magnitude of the output voltage is output to any one of the multiple power lines. By detecting the change in the magnitude of the voltage value output via that one power line, the system circuit 22 can perform processing according to the power cut-off. Note that in this case, the power line whose voltage value is to be changed may be a different power line from the power line used to supply power to the system circuit 22. In this case, even if the magnitude of the voltage value changes relatively greatly, it has almost no effect on the power supply of the system circuit 22, making it easier for the system circuit 22 to detect the change in voltage value. Alternatively, the power supply unit 10 may perform such control as changing the voltage value of the power line used to supply power to the system circuit 22 and, for example, cutting off power from other power lines. In this situation, although system circuit 22 can perform the termination process by using power supplied from the power line whose voltage value has changed, power supply unit 10 can quickly cut off the power supply to the power line or line that has no effect on the termination process, and thus can continue to supply power to system circuit 22 for a relatively long period of time.

[0031] Furthermore, in the above description, the voltage value V2 of the output voltage Vo output by the power supply unit 10 during power cut-off detection has been assumed to be less than the voltage value V1 used during normal time. However, the voltage value V2 only needs to be the value of the voltage at which the power supply circuit 21 can output the operating voltage Vr to the system circuit 22; the voltage value V2 can be greater than the voltage value V1.

[0032] Furthermore, in the above description, it has been assumed that the power supply unit 10 is integrated into the electronic device 1; however, the power supply unit 10 may be a unit independent of the electronic device 1. Specifically, the power supply unit 10 may be an AC adapter or the like that connecting the electronic device 1 and an external power supply P. In this case, the power supply unit 10 changes the magnitude of the output voltage Vo upon detecting a power cut-off from the external power supply P, and the electronic device 1 detects the change in the output voltage Vo, enabling processing to be performed according to the power supply switching.

[0033] [List of Reference Symbols]

[0034] 1: Electronic devices

[0035] 10: Power Supply Unit

[0036] 11: AC / DC converter

[0037] 12: Control Circuit

[0038] 20: Main Unit

[0039] 21: Power supply circuit

[0040] 22: System Circuit

[0041] 22a: A / D converter

Claims

1. An electronic device, comprising: Power supply unit; as well as Main unit, wherein: The power supply unit includes: The output section converts the power supplied from the external power source into a DC voltage of a first voltage value and outputs the DC voltage to the main unit; and In the control section, when the power supply from the external power source has been cut off, the value of the DC voltage output by the output section is changed to a second voltage value that is lower than the first voltage value. When the value of the DC voltage output by the power supply unit has changed to the second voltage value, the main unit performs a predetermined termination process, and If, within a predetermined time period after the DC voltage value has changed to the second voltage value, the DC voltage value is detected to be lower than the second voltage value, the main unit performs a process different from the predetermined termination process.

2. The electronic device according to claim 1, wherein: The main unit includes a processing circuit that performs the predetermined termination process, and The second voltage value is a value greater than the operating voltage of the processing circuit.

3. The electronic device according to claim 1, wherein, The process, which differs from the predetermined termination process, includes writing log data indicating that an exception has occurred.

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