JP2018196222A - Electronic equipment, control method and program - Google Patents

Abstract

To stop electronic equipment in a normal shutdown sequence without abnormally terminating the electronic equipment even when excess current is generated by a user-driven operation.SOLUTION: Electronic equipment (15) has: input voltage detection means for detecting an input voltage level of the electronic equipment; input impedance detection means for detecting input impedance of the electronic equipment; first calculation means for calculating voltage drop on the basis of an operation mode of the electronic equipment, the input voltage level of the electronic equipment, and the input impedance of the electronic equipment; second calculation means for calculating a threshold which does not become less than a threshold for stopping the electronic equipment on the basis of the calculated voltage drop; and update means for updating a threshold for excess current protection which is currently set by the calculated threshold when the calculated threshold is lower than the threshold for excess current protection which is currently set, and lower than a threshold by a normally supposed load.SELECTED DRAWING: Figure 1

Description

  The present invention relates to an electronic device capable of detecting an overcurrent, a control method thereof, and a program related thereto.

  In an electronic device with an externally exposed power supply terminal for supplying power to the lens unit or external accessory (eg, interchangeable lens camera), there is a high possibility that the power supply terminal will be shorted and the circuit inside the electronic device will be shorted. Become. Therefore, in such an electronic device, when an overcurrent occurs due to a short circuit of a power supply terminal or the like, a function for protecting a circuit in the electronic device from the overcurrent is required. The overcurrent can be detected from the voltage value at both ends of a current detection resistor connected in series to the power supply line, or can be detected from the coil current of the choke coil. When an overcurrent occurs, the circuit in the electronic device is protected by stopping the operation of the electronic device.

  Patent Document 1 describes a method of continuing the operation of an electronic device while protecting the specific circuit by stopping only the DC / DC converter that supplies power to the specific circuit in which an overcurrent is detected. Yes.

JP 2011-62060 A

  However, in the method described in Patent Document 1, depending on the input voltage level of the electronic device, the operating load, or the input impedance to the DC / DC converter, the input voltage level determines whether the electronic device continues to operate when an overcurrent occurs. May be lower than the drive control voltage. In that case, the electronic device ends abnormally.

  Therefore, the present invention is to stop an electronic device in a normal shutdown sequence without abnormally ending the electronic device even when an overcurrent occurs in a user-driven operation (such as replacement of a lens unit). For the purpose.

  In order to achieve the above object, an electronic device according to the present invention includes an input voltage detection unit that detects an input voltage level of the electronic device, an input impedance detection unit that detects an input impedance of the electronic device, First calculation means for calculating a voltage drop from an operation mode, an input voltage level of the electronic device, and an input impedance of the electronic device, and a threshold for stopping the electronic device from the calculated voltage drop is not less than A second calculating means for calculating a threshold value, and when the calculated threshold value is lower than a currently set threshold value for overcurrent protection and lower than a threshold value in a normally assumed load, And updating means for updating the threshold value for overcurrent protection that is used with the calculated threshold value.

  In order to achieve the above object, a control method according to the present invention is a method for controlling an electronic device, wherein an input voltage detection step for detecting an input voltage level of the electronic device and an input impedance of the electronic device are detected. From the input impedance detection step, the operation mode of the electronic device, the input voltage level of the electronic device, the first calculation step of calculating the voltage drop from the input impedance of the electronic device, and the calculated voltage drop, A second calculation step of calculating a threshold value that does not fall below a threshold value for stopping the electronic device, and the calculated threshold value is lower than a currently set threshold value for overcurrent protection, and is normally at an assumed load; If the threshold value is lower than the threshold value, an update step of updating the currently set threshold value for overcurrent protection with the calculated threshold value is included.

  In order to achieve the above object, a program according to the present invention includes a computer, an input voltage detection unit that detects an input voltage level of an electronic device, an input impedance detection unit that detects an input impedance of the electronic device, and the electronic device. A first calculating means for calculating a voltage drop from an operation mode of the equipment, an input voltage level of the electronic equipment, and an input impedance of the electronic equipment; and a threshold for stopping the electronic equipment from the calculated voltage drop. A second calculating means for calculating a threshold value that does not fall below, and when the calculated threshold value is lower than a currently set threshold value for overcurrent protection and lower than a normally assumed load threshold value, This is a program for causing a currently set threshold value for overcurrent protection to function as an updating unit that updates a calculated threshold value.

  According to the present invention, even when an overcurrent occurs in a user-driven operation (such as replacement of a lens unit), the electronic device can be stopped in a normal shutdown sequence without abnormally terminating the electronic device. .

FIG. 3 is a block diagram for explaining components of the electronic device 15 according to the first embodiment. 4 is a flowchart for explaining an operation example in the electronic device 15. 3 is a block diagram for explaining components of a threshold control unit 17. FIG. 3 is a timing chart in the first embodiment.

  Hereinafter, embodiments of the present invention will be described with reference to the drawings. However, the present invention is not limited to the following embodiments.

[Embodiment 1]
FIG. 1 is a block diagram for explaining components of the electronic device 15 according to the first embodiment. In the first embodiment, an example in which the electronic device 15 operates as an imaging device capable of exchanging lens units will be described.

  Upon receiving a command from a system control unit 2 in a CPU (central processing unit) 1 that controls the entire electronic device 15, the imaging control unit 3 controls an AFE (analog front end) 4 based on the command. The AFE 4 plays a role of driving control of the image sensor 5 in accordance with an instruction from the image capture control unit 3 and converting an image signal obtained from the image sensor 5 into image signal data and delivering it to the CPU 1. The commands from the imaging control unit 3 are serial communication for changing register settings of the AFE 4 and the like, a reference clock signal of the imaging sensor 5, a horizontal drive signal HD, a vertical drive signal VD, and the like.

  Light from the subject is photoelectrically converted by the image sensor 5 controlled in this way, converted to image data by the AFE 4, and taken into the memory 6 of the CPU 1. In the imaging standby state in which the through image is displayed, the image data captured from the imaging sensor 5 and the AFE 4 in response to the through image thinning drive command from the system control unit 2 is developed in the memory 6. The acquired image data is converted into display data by the display image conversion unit 9 and displayed on the display unit 11 via the display driver 10. When the user presses the release button, the image data generated by the AFE 4 according to an instruction from the imaging control unit 3 is taken into the memory 6. The image data developed on the memory 6 is corrected by the image correction unit 8 and recorded in the recording unit 12 as a still image or a moving image. In addition, it has a mode lever 16 for setting the operation mode of the electronic device 15. Although not shown for the sake of simplification, a shutter unit for capturing a still image, a motor for shutter control, a motor driver for driving the motor, and an operation unit for user input are also provided.

  The electronic device 15 is provided with a mechanical holding structure and an electric contact for transmitting an electric signal so that the user can freely select and remove the interchangeable lens unit 49 having different optical characteristics and functions. It has been. The electric contacts are roughly classified into two types, that is, a power contact 52 such as a power source for driving and a ground terminal, and a communication contact 50 for transmitting a control signal such as communication. The communication contact 50 is configured to connect the communication control unit 7 in the CPU 1 of the electronic device 15 and the lens control unit 51 in the lens unit 49. The communication control unit 7 exchanges information with the system control unit 2, transmits a command from the system control unit 2 to the lens control unit 51, and performs system control on state information of the lens unit 49 sent from the lens control unit 51. It plays the role of transmitting to part 2. On the other hand, the power contact 52 plays a role of transmitting lens driving power supplied from the power supply unit 13 in the electronic device 15 to be described later. The lens driving unit 53 drives a focus motor, a camera shake correction motor, and the like in the lens unit 49 using electric power supplied via the power contact 52 based on a command from the lens control unit 51. These operations enable imaging that reflects the user's intention.

  The power supply unit 13 uses the power supplied from the battery 18 to convert it into a voltage necessary for various devices and supply power. Since each device requires different voltages and currents, there are a plurality of power supply systems. In FIG. 1, the electronic device 15 supplies power to the lens drive boosting power supply circuit 14, the CPU 1, and other loads 48. An example having other power supply circuit 47 will be described. Moreover, the electric power supplied to the power supply part 13 is protected by the protective element A19. Furthermore, since the booster power supply circuit 14 is supplied to the external lens driving unit 53 via the power contact 52, it is protected by the protective element B20. The step-up power supply circuit 14 supplies power not only for lens driving but also to another device driving circuit 46 in the electronic device 15. The power line for driving the lens via the power contact 52 exposed to the outside of the electronic device 15 is supplied via the protection SW 45 for short-circuit protection, and the power line to another device drive circuit 46 inside the apparatus is The connection is made without going through the protection SW 45. This is because when the lens drive power supply is short-circuited, the short-circuited lens drive power supply side cuts off the supply while allowing the supply to another device drive circuit 46 to be continued. If the entire boosting power supply circuit 14 is stopped at the time of a short circuit, the power supply to the separate device drive circuit 46 is also stopped, and the convenience of the user is impaired because the electronic device 15 must be restarted each time. This is the configuration. The protection SW 45 is configured to be cut off when an overcurrent is detected by the overcurrent detection circuit 44 and to be connected during normal operation. The overcurrent detection circuit 44 detects that an overcurrent has passed through the boost power supply circuit 14. When detected, the protection SW 45 is shut off. The threshold control unit 17 controls the threshold when the overcurrent detection circuit 44 detects the overcurrent.

  Next, an operation example in the electronic device 15 will be described with reference to FIG. 2, and components of the threshold control unit 17 will be described with reference to FIG. Hereinafter, a case where an overcurrent occurs in a user-driven operation (such as replacement of the lens unit 49) will be considered. Also in this case, the electronic device 15 does not end abnormally and stops in a normal sequence regardless of the input voltage level of the electronic device 15, the operating load of the electronic device 15, and the input impedance from the battery 18 to the power supply unit 13. Calculate the overcurrent protection threshold as possible.

  The threshold control unit 17 includes an input voltage detection unit 55 that detects a voltage output from the battery 18 and a mode detection unit 56 that detects an operation mode of the electronic device 15. The mode detection unit 56 detects the operation mode of the electronic device 15 based on a signal corresponding to the mode position set by the user with the mode lever 16. Furthermore, an input impedance detection unit 57 that detects an input impedance from the battery 18 to the power supply unit 13 is provided. Here, the input impedance detection unit 57 can calculate the voltage drop between the output voltage level of the battery 18 and the input voltage level of the power supply unit 13 when a known load current is drawn.

  When the electronic device 15 is activated, initial settings necessary for the operation of the electronic device 15 are made. Further, for the overcurrent detection circuit 44, a value stored in advance in a memory unit (not shown) in the CPU 1 is set by the threshold control unit 17 as an initial value of the overcurrent protection threshold Ith (step S201).

  The input voltage detection unit 55 detects the input voltage Vin, and the mode detection unit 56 detects the operation mode of the electronic device 15. Furthermore, information on the input impedance Z until the input impedance detection unit 57 inputs from the battery 18 to the power supply unit 13 is acquired (step S202).

  Next, the input voltage level Vmin when the overcurrent is generated is calculated by the second calculator 59 (step S203). First, the voltage drop ΔV when an overcurrent occurs is ΔV = Z × Iin (Iin: overcurrent). Therefore, the input voltage level Vmin when an overcurrent occurs can be calculated by Vmin = Vbatt−ΔV. Here, Vbatt is an input voltage level at no load.

  Next, the calculated Vmin is compared with each threshold value for determining whether or not the input voltage level can continue the operation of the electronic device 15. Here, it is assumed that two types of threshold values are set in the electronic device 15. One is a voltage level necessary for converting the voltage supplied to the CPU 1 or the like in the power supply unit 13 and is Vsys. When the voltage level supplied to the power supply unit 13 falls below Vsys, the electronic device 15 immediately stops all operations. When Vsys is detected and the electronic device 15 is stopped, the image being recorded cannot be stored, or the process of placing the lens barrel in the electronic device 15 cannot be executed. Therefore, as a second threshold value, Vlb which is a voltage level higher than Vsys is provided according to the normally assumed operating load so as not to fall below Vsys in the normally assumed operating load of the electronic device 15. When the voltage level supplied to the power supply unit 13 is lower than Vlb, it is assumed that Vlb is lower than Vsys in the normally assumed operating load of the electronic device 15, and thus the electronic device 15 is passed through a normal shutdown sequence. This is a threshold value to be stopped.

  The input voltage level Vmin when an overcurrent occurs is compared with Vlb (step S204). As a result of the comparison, if Vmin is higher than Vlb, the process returns to step S202. On the other hand, if it is lower than Vlb, it is compared with Vsys (step S205). As a result of comparison, if it is lower than Vsys, it is expected that if an overcurrent occurs, Vmin will fall below Vsys and all operations will be stopped immediately. Therefore, the first calculator 58 calculates an overcurrent protection threshold value such that Vmin does not fall below Vsys even when an overcurrent occurs (step S206). Next, in the threshold update unit 60, the overcurrent protection threshold at which the calculated Vmin is not lower than Vsys is compared with the currently set overcurrent protection threshold (step S207), and if it is higher, the process returns to step S202. On the other hand, if the calculated overcurrent protection threshold is lower than the threshold at the load that is normally assumed, the currently set overcurrent protection threshold is updated with the calculated overcurrent protection threshold. The process returns to step S202 again (step S208).

  On the other hand, if Vmin is higher than Vsys as a result of comparing Vmin and Vsys in step S205, when an overcurrent occurs, Vmin falls below Vlb, and the electronic device 15 is stopped through a normal shutdown sequence. Therefore, an overcurrent protection threshold is calculated so that Vmin does not fall below Vlb even when an overcurrent occurs (step S209).

  The overcurrent protection threshold value at which the calculated Vmin does not fall below Vlb is compared with the currently set overcurrent protection threshold value (step S210), and if it is higher, the process returns to step S202. On the other hand, if the calculated overcurrent protection threshold is lower than the normally assumed load threshold, the currently set overcurrent protection threshold is updated with the calculated overcurrent protection threshold. The process returns to step S202 again (step S210).

Next, an operation example of the electronic device 15 will be described with specific numerical values with reference to the timing chart of FIG. FIG. 4 is a diagram showing the time t on the horizontal axis and the voltage level V of Vbatt on the vertical axis. Here, it is assumed that the thresholds set to continue the operation of the electronic device 15 are Vlb = 3.0V and Vsys = 2.7V. First, state A shown in the range of time t1 to t2 is assumed that Vbatt = 3.7V, input impedance Z = 200Ω, and operation load Im = 0.8 A when electronic device 15 is in the live view display state. When overcurrent I1 = 2.0 A occurs in state A, the voltage drop ΔV of Vbatt is
ΔV = Z × (Im + I1) = 200Ω × (0.8A + 2.0A) = 0.56V.

  As a result, Vmin = Vbatt−ΔV = 3.7V−0.56V = 3.14V, and does not fall below the threshold value Vlb = 3.0V set for continuing the operation of the electronic device 15. Accordingly, when an overcurrent occurs, the overcurrent detection circuit 44 detects the overcurrent, the protection SW 45 can be set to OPEN, and the power supply only to the lens driving unit 53 can be stopped, so that the electronic device 15 operates. Can continue.

Next, state B shown in the range of time t3 to t4 is Vbatt = 3.5V, input impedance Z = 200Ω, and operating load Im = 0.8 A when electronic device 15 is in the live view display state. When the mechanical drive current I1 = 1.2 A normally assumed in the state B is generated, the voltage drop ΔV of Vbatt is
ΔV = Z × (Im + I1) = 200Ω × (0.8A + 1.2A) = 0.40V.

  As a result, Vmin = Vbatt−ΔV = 3.5V−0.40V = 3.1V, and does not fall below the threshold value Vlb = 3.0V set for continuing the operation of the electronic device 15. Therefore, as in the state A, when an overcurrent occurs in the user-driven operation, the overcurrent is detected by the overcurrent detection circuit 44 and the power supply only to the lens driving unit 53 can be stopped. 15 can continue the operation.

Next, state C shown in the range of time t5 to t6 is Vbatt = 3.5V, input impedance Z = 200Ω, and operating load Im = 0.8 A when electronic device 15 is in the live view display state. When overcurrent I1 = 2.0 A occurs in state B, the voltage drop ΔV of Vbatt is
ΔV = Z × (Im + I1) = 200Ω × (0.8A + 2.0A) = 0.56V.

As a result, Vmin = Vbatt−ΔV = 3.5V−0.56V = 2.94V, which is lower than the threshold value Vlb = 3.0V set for continuing the operation of the electronic device 15. As a result, in state B and state C, Vbatt, input impedance Z, and operating load Im are the same. However, when an overcurrent occurs, the overcurrent detection circuit 44 detects the overcurrent, and not only stops the power supply of the lens driving unit 53 but also stops the operation of the electronic device 15 through a normal shutdown sequence. It will be. Therefore, in the state B and the state C, the operation is continued during the normally assumed mechanical drive, and when an overcurrent occurs in the user-driven operation, the power supply only to the lens drive unit 53 is stopped, and the electronic device 15 operations are required to be continued. Accordingly, it is necessary to set ΔV to Vmin equal to or greater than 3.00V, that is, ΔV = Vbatt−Vmin = 3.5V−3.00V = less than 0.5V. Where ΔV is
ΔV = Z × (Im + I1)
It can be calculated with

  0.5V = 200Ω × (0.8A + I1), and if the overcurrent I1 can be detected at less than 1.7A, the operation of the electronic device 15 continues as shown by the state C ′ in the range of time t7 to t8. The threshold value Vlb set to be less than 3.0V is not exceeded. Furthermore, it is possible to stop the power supply of only the lens driving unit 53 and continue the operation of the electronic device 15. Therefore, the threshold control unit 17 sets the overcurrent protection threshold value to 1.6 A for the overcurrent detection circuit 44 (however, since it is necessary to operate it even during the normally assumed mechanical drive, Must be 1.2 A or more).

Next, it is assumed that the state D shown in the range of time t9 to t10 is Vbatt = 3.2V, input impedance Z = 200Ω, and the operation load Im = 0.8 A when the electronic device 15 is in the live view display state. When the mechanical drive current I1 = 1.2 A normally assumed in the state D is generated, the voltage drop ΔV of Vbatt is
ΔV = Z × (Im + I1) = 200Ω × (0.8A + 1.2A) = 0.40V.

  As a result, Vmin = Vbatt−ΔV = 3.2V−0.40V = 2.8V, and does not fall below the threshold value Vsys = 2.7V set for continuing the operation of the electronic device 15.

Next, it is assumed that the state E shown in the range of time t11 to t12 is Vbatt = 3.2V, input impedance Z = 200Ω, and the operation load Im = 0.8 A when the electronic device 15 is in the live view display state. When overcurrent I1 = 2.0 A occurs in state E, the voltage drop ΔV of Vbatt is
ΔV = Z × (Im + I1) = 200Ω × (0.8A + 2.0A) = 0.56V.

As a result, Vmin = Vbatt−ΔV = 3.2V−0.56V = 2.64V, which is lower than the threshold value Vsys = 2.7V set for continuing the operation of the electronic device 15. As a result, in state D and state E, Vbatt, input impedance Z, and operation load Im are the same. However, when an overcurrent occurs in a user-driven operation (such as replacement of the lens unit 49), the overcurrent detection circuit 44 detects the overcurrent and not only stops the power supply of the lens driving unit 53, but also an electronic device. All 15 operations will be stopped immediately. Therefore, in the state D and the state E, the operation is stopped by a normal shutdown sequence at the time of mechanical driving that is normally assumed. On the other hand, when an overcurrent occurs in the user-driven operation, it is required to stop the power supply of only the lens driving unit 53 and continue the operation of the electronic device 15. Therefore, it is necessary to set ΔV to Vmin equal to or higher than 2.7V, that is, ΔV = Vbatt−Vmin = 3.2V−2.7V = less than 0.5V. Where ΔV is
ΔV = Z × (Im + I1)
It can be calculated with

  0.5V = 200Ω × (0.8A + I1) If the overcurrent I1 can be detected at less than 1.7A, the operation of the electronic device 15 continues as shown by the state E ′ in the range of time t13 to t14. Therefore, the threshold value Vsys set to be less than 2.7V is not exceeded. As a result, it can be stopped by a normal shutdown sequence. Therefore, the threshold control unit 17 sets the overcurrent protection threshold value to 1.6 A for the overcurrent detection circuit 44 (however, since it is necessary to operate it even during the normally assumed mechanical drive, Must be 1.2 A or more).

Although not shown in FIG. 4, it is assumed that the state F is Vbatt = 3.3 V, the input impedance Z = 200Ω, and the operating load Im = 0.4 A when the electronic device 15 is in the standby mode. At this time, when the normally assumed mechanical drive current I1 = 1.2 A is generated, the voltage drop ΔV of Vbatt is
ΔV = Z × (Im + I1) = 200Ω × (0.4A + 1.2A) = 0.32V.

  As a result, Vmin = Vbatt−ΔV = 3.3V−0.32V = 2.98V, and does not fall below the threshold value Vsys = 2.7V set for continuing the operation of the electronic device 15.

On the other hand, when an overcurrent I1 = 2.0 A occurs in the state F, the voltage drop ΔV of Vbatt is
ΔV = Z × (Im + I1) = 200Ω × (0.4A + 2.0A) = 0.48V.

As a result, Vmin = Vbatt−ΔV = 3.3V−0.48V = 2.82V, and it is less than the threshold value Vsys = 2.7V set for continuing the operation of the electronic device 15 as in the mechanical drive. Absent. However, ΔV for setting Vmin, which is a threshold value Vlb = 3.0V or more set for continuing the operation of the electronic device 15, to 3.0V or more, that is, ΔV = Vbatt−Vmin = 3.3V−3.0V = 0. Must be less than 3V. Where ΔV is
ΔV = Z × (Im + I1)
It can be calculated with

  0.3V = 200Ω × (0.4A + I1), and if the overcurrent I1 can be detected at less than 1.1 A, the threshold value Vlb set to continue the operation of the electronic device 15 should be below 3.0V. It can be stopped with a normal shutdown sequence. However, since a current of 1.2 A is assumed at the time of the mechanical drive that is normally assumed, if the overcurrent protection threshold is set to 1.1 A, the mechanical drive cannot be performed, so the state F updates the overcurrent protection threshold. do not do.

  Further, when the overcurrent detection circuit 44 detects an overcurrent, the protection SW 45 is set to OPEN, and the power supply only to the lens driving unit 53 is stopped, the operation of the electronic device 15 is continued. May be supplied. In that case, the threshold update unit 60 determines the mode for restarting the power supply by closing the protection SW 45 according to the result of the mode detection unit 56 when the overcurrent detection circuit 44 detects the overcurrent. May be. For example, when the result of the mode detection unit 56 when the overcurrent is detected by the overcurrent detection circuit 44 is a mode with a large load, a larger load is applied to the protection element A19. That is, depending on the result of the mode detector 56, the damage given to the protective element is also different. Damage is accumulated in the protective element A19 by returning to the mode in which the load is larger than when the overcurrent is detected by the overcurrent detection circuit 44.

  As described above, according to the first embodiment, even when an overcurrent occurs during a user-driven operation (such as replacement of a lens unit), the electronic device 15 can be electronically operated in a normal shutdown sequence without abnormal termination. The device 15 can be stopped.

[Embodiment 2]
The various functions, processes, or methods described in the first embodiment can also be realized by a personal computer, a microcomputer, a CPU (central processing unit), a processor, and the like using a program. Hereinafter, in the second embodiment, a personal computer, a microcomputer, a CPU (central processing unit), a processor, and the like are referred to as “computer X”. In the second embodiment, a program for controlling the computer X and realizing the various functions, processes, or methods described in the first embodiment is referred to as “program Y”.

  The various functions, processes, or methods described in the first embodiment are realized by the computer X executing the program Y. In this case, the program Y is supplied to the computer X via a computer-readable storage medium. The computer-readable storage medium according to the second embodiment includes at least one of a hard disk device, a magnetic storage device, an optical storage device, a magneto-optical storage device, a memory card, a volatile memory, and a nonvolatile memory. The computer-readable storage medium in Embodiment 2 is a non-transitory storage medium.

  The embodiment of the present invention is not limited to the above-described first or second embodiment. Embodiments 1 and 2 that are changed or modified without departing from the gist of the invention are also included in the embodiments of the present invention.

  15 Electronic equipment

Claims (5)

Input voltage detection means for detecting the input voltage level of the electronic device;
Input impedance detection means for detecting the input impedance of the electronic device;
First calculation means for calculating a voltage drop from an operation mode of the electronic device, an input voltage level of the electronic device, and an input impedance of the electronic device;
Second calculation means for calculating a threshold value that does not fall below a threshold value for stopping the electronic device from the calculated voltage drop;
If the calculated threshold is lower than the currently set threshold for overcurrent protection and lower than the normally assumed load threshold, set the currently set threshold for overcurrent protection. And an updating means for updating with the calculated threshold value.   The electronic device according to claim 1, wherein the update unit determines an operation mode for resuming power supply in accordance with an operation mode of the electronic device when power supply is stopped.   The electronic device according to claim 1, further comprising a control unit that performs control for stopping power supply to the load in which the overcurrent is detected. An electronic device control method comprising:
An input voltage detecting step for detecting an input voltage level of the electronic device;
An input impedance detection step of detecting an input impedance of the electronic device;
A first calculation step of calculating a voltage drop from an operation mode of the electronic device, an input voltage level of the electronic device, and an input impedance of the electronic device;
A second calculation step for calculating a threshold value that does not fall below a threshold value for stopping the electronic device from the calculated voltage drop;
If the calculated threshold is lower than the currently set threshold for overcurrent protection and lower than the normally assumed load threshold, set the currently set threshold for overcurrent protection. And an updating step for updating with the calculated threshold value. Computer
Input voltage detection means for detecting the input voltage level of the electronic device;
Input impedance detection means for detecting the input impedance of the electronic device;
First calculation means for calculating a voltage drop from an operation mode of the electronic device, an input voltage level of the electronic device, and an input impedance of the electronic device;
Second calculation means for calculating a threshold value that does not fall below a threshold value for stopping the electronic device from the calculated voltage drop;
If the calculated threshold is lower than the currently set threshold for overcurrent protection and lower than the normally assumed load threshold, set the currently set threshold for overcurrent protection. A program for functioning as update means for updating with a calculated threshold value.

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