Electronic apparatus and control method for the same

Abstract

To provide an electronic apparatus capable of suppressing a change of a supply voltage at the time of switching of power supply means to be used and a control method for the same.SOLUTION: An electronic apparatus can switch power supply means to be used. The electronic apparatus includes: a first voltage conversion circuit in which an output voltage is 1 / n (n is an integer equal to two or greater) of an input voltage; a second voltage conversion circuit that converts the input voltage into a set output voltage; and a third voltage conversion circuit that converts a higher one of the output voltages of the first and second voltage conversion circuits and supplies it to a load. In a case where the input voltage from the first voltage conversion circuit is supplied to the first voltage conversion circuit, the electronic apparatus sets the output voltage of the second voltage conversion circuit to a first voltage that is close to the output voltage of the first voltage conversion circuit when a voltage from the first voltage conversion circuit was input to the first voltage conversion circuit . The electronic apparatus then performs control for supplying the input voltage from the first power supply circuit to the first voltage conversion circuit after making a setting such that the output voltage of the second voltage conversion circuit will be the first voltage.SELECTED DRAWING: Figure 1

Description

[Technical field]

[0001] The present invention relates to an electronic device and a control method thereof. [Background technology]

[0002] In order to achieve stable operation in electronic devices that can use different power supply means, such as a power-supply interface, a battery, or an AC adapter, a function has been proposed to dynamically switch the power supply means to be used (Patent Document 1). [Prior art documents] [Patent documents]

[0003] [Patent Document 1] JP 2001-166854 A Summary of the Invention [Problem to be solved by the invention]

[0004] In Patent Document 1, when the power consumption of an electronic device exceeds the power that can be supplied through an interface, the operation of the electronic device is maintained by supplying power from a battery. However, if the supply voltage changes suddenly when the power supply means is switched, this can cause malfunctions or a decrease in processing quality. Patent Document 1 does not take such voltage fluctuations into consideration at all.

[0005] In consideration of the problems with the conventional technology, the present invention, in one embodiment, provides an electronic device and a control method thereof that are capable of suppressing changes in supply voltage when switching the power supply means used. [Means for solving the problem]

[0006] In one aspect, the present invention provides an electronic device capable of switching the power supply means used, the electronic device having: first voltage conversion means for converting an input voltage from a first power supply means or a second power supply means into an output voltage, the output voltage being 1 / n (n is an integer equal to or greater than 2) of the input voltage; second voltage conversion means for converting the input voltage from the second power supply means into a set output voltage; third voltage conversion means for converting the higher of the output voltage of the first voltage conversion means and the output voltage of the second voltage conversion means and supplying it to a load; and control means for controlling the operation of the second voltage conversion means, wherein when the input voltage from the first power supply means is supplied to the first voltage conversion means, the control means sets the output voltage of the second voltage conversion means to a first voltage that is close to the output voltage of the first voltage conversion means when the voltage from the first power supply means is input to the first voltage conversion means, and performs control to supply the input voltage from the first power supply means to the first voltage conversion means after setting the output voltage of the second voltage conversion means to the first voltage. Effect of the Invention

[0007] According to one embodiment of the present invention, it is possible to provide an electronic device capable of suppressing a change in supply voltage when switching the power supply means to be used, and a control method thereof. [Brief description of the drawings]

[0008] [Figure 1] FIG. 1 is a block diagram showing an example of the functional configuration of an imaging device as an example of an electronic device according to an embodiment. [Diagram 2] Flowchart of power supply control operation according to the embodiment [Diagram 3] Timing chart regarding power supply control operation according to the embodiment DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0009] The present invention will be described in detail below based on its exemplary embodiments with reference to the accompanying drawings. Note that the following embodiments do not limit the invention according to the claims. In addition, although multiple features are described in the embodiments, not all of them are necessarily essential to the invention, and multiple features may be combined arbitrarily. Furthermore, in the accompanying drawings, the same reference numbers are used for the same or similar configurations, and duplicated explanations are omitted.

[0010] In the following embodiment, the present invention will be described with respect to a case where the present invention is implemented in an imaging device (digital camera). However, imaging functionality is not essential to the present invention, and the present invention can also be implemented in any electronic device that can dynamically switch between multiple types of power supply means. Such electronic devices include video cameras, computer devices (personal computers, tablet computers, media players, PDAs, etc.), mobile phones, smartphones, game consoles, robots, drones, and drive recorders. These are merely examples, and the present invention can also be implemented in other electronic devices.

[0011] 1 is a block diagram showing an example of the functional configuration of an imaging device 101 as an example of an electronic device according to the present invention. Note that Fig. 1 mainly shows the functional configuration related to power supply, and only a part of the other functional configuration is shown.

[0012] The imaging device 101 can dynamically switch between a plurality of power supply means. In this example, the power supply means available are an external power source 200 connected to the interface 102 and a battery 107. However, there is no particular limit to the number (two or more) and type of power supply means. For example, the battery 107 may be either detachable (e.g., a battery pack) or non-detachable.

[0013] The interface 102 is an interface, such as a USB interface, that can receive power from an external device connected to the imaging device 101. Therefore, the imaging device 101 can receive power through the interface 102, the power being determined according to the specifications of the interface 102 and the specifications of the external device connected to the interface 102.

[0014] Here, the external device connected to the interface 102 via the cable 300 is assumed to be an external power source 200 such as an AC adapter or a portable battery. However, the external device does not have to be a power source. Hereinafter, the supply of power via the interface 102 will be referred to as external power supply.

[0015] The power receiving circuit 103 outputs (through output) the voltage supplied through the interface 102 without converting it. The power receiving circuit 103 may have a load switch. The power receiving circuit 103 also has a function of limiting the current flowing through the interface 102 to an upper limit value determined according to the specifications of the interface 102, for example. Note that the function of limiting the current flowing through the interface 102 may be provided by an external device (here, the external power supply 200) connected to the interface 102.

[0016] The battery 107 is, for example, a removable battery pack. The battery 107 has a maximum output voltage according to its configuration. The output voltage of the battery 107 varies according to the state of the battery 107. In this embodiment, the battery 107 has two lithium ion cells, and the output voltage of the battery 107 varies between 8.4 V (when fully charged) and 5.0 V according to the state of charge. The output voltage of the battery 107 is input to the third switch 110 and the second voltage conversion circuit 108.

[0017] The third switch 110 is provided between the connection path between the power receiving circuit 103 and the first voltage conversion circuit 104 and the output of the battery 107. When the third switch 110 is ON, the output voltage of the battery 107 is applied to the connection path through the third switch 110. When the third switch 110 is OFF, the output voltage of the battery 107 is not applied to the connection path.

[0018] When power is not being supplied to the imaging device 101 from the external power source 200 via the interface 102 and the imaging device 101 operates on power from the battery 107, the third switch 110 is turned ON. This causes the output voltage of the battery 107 to be input to both the first voltage conversion circuit 104 and the second voltage conversion circuit 108. In addition, when power is being supplied to the imaging device 101 from the external power source 200 via the interface 102, the third switch 110 is turned OFF. The ON and OFF of the third switch 110 is controlled by a power supply control circuit 112.

[0019] The imaging device 101 has a first voltage conversion circuit 104, a second voltage conversion circuit 108, and a third voltage conversion circuit 111. The higher of the output voltages of the first voltage conversion circuit 104 and the second voltage conversion circuit 108 is input to the third voltage conversion circuit 111. The range of input voltages allowed by the third voltage conversion circuit 111 includes the normal ranges that the output voltages of the first voltage conversion circuit 104 and the second voltage conversion circuit 108 can take.

[0020] The first voltage conversion circuit 104 has a higher voltage conversion efficiency than the second voltage conversion circuit 108. There is no limitation on the method for satisfying such a relationship in voltage conversion efficiency. Here, the first voltage conversion circuit 104 and the second voltage conversion circuit 108 use different voltage conversion methods. Specifically, the first voltage conversion circuit 104 is a switched capacitor converter, and the second voltage conversion circuit 108 is a switching DC-DC converter.

[0021] In a switched capacitor converter, the ratio of the output voltage to the input voltage is an integer. Since the first voltage conversion circuit 104 is used as a step-down circuit, the output voltage is n times or 1 / n times (n is an integer of 2 or more) the input voltage. In this embodiment, the first voltage conversion circuit 104 uses two flying capacitors 105 to convert the input voltage to 1 / 2 and output the input voltage.

[0022] The second voltage conversion circuit 108 converts the input voltage supplied from the battery 107 into an output voltage according to a set value. The second voltage conversion circuit 108 is not a switched capacitor converter, and the output voltage is not limited to n times or 1 / n times (n is an integer of 2 or more) the input voltage. The output voltage of the second voltage conversion circuit 108 is set by the power supply control circuit 112.

[0023] The first voltage conversion circuit 104 is connected to the third voltage conversion circuit 111 via a first switch 106. The second voltage conversion circuit 108 is connected to the third voltage conversion circuit 111 via a second switch 109. The outputs of the first switch 106 and the second switch 109 are connected together before the third voltage conversion circuit 111. The first switch 106 and the second switch 109 are examples of circuits that prevent backflow to the first voltage conversion circuit 104 and the second voltage conversion circuit 108, respectively.

[0024] For example, the first switch 106 and the second switch 109 may each be a diode with a cathode connected to the third voltage conversion circuit 111, or may be a load switch. When the first switch 106 and the second switch 109 are realized as load switches, they may be configured to turn on when a voltage is applied from an upstream voltage conversion circuit and prevent reverse current when in the on state. When a load switch is used, the conduction loss can be reduced compared to when a diode is used. Also, the first switch 106 and the second switch 109 may be realized as a semiconductor device called an ideal diode.

[0025] Therefore, the third voltage conversion circuit 111 receives the higher of the output voltages of the first voltage conversion circuit 104 and the second voltage conversion circuit 108. In a state in which the imaging device 101 operates with power from the battery 107, the output voltage of the second voltage conversion circuit 108 is set to a value close to and above the lower limit of the voltage at which the third voltage conversion circuit 111 can operate. For example, the output voltage of the second voltage conversion circuit 108 is set to a voltage that is higher than the lower limit of the voltage at which the third voltage conversion circuit 111 can operate by a predetermined value. As a result, in a state in which the output voltage of the battery 107 is high, the output voltage of the first voltage conversion circuit 104 is output to the third voltage conversion circuit 111. Then, even if the voltage of the battery 107 drops and the output voltage of the first voltage conversion circuit 104 falls below the output voltage of the second voltage conversion circuit 108, the third voltage conversion circuit 111 is supplied with an operable voltage from the second voltage conversion circuit 108.

[0026] This makes it possible to utilize the first voltage conversion circuit 104, which has good voltage conversion efficiency, when the output voltage of the battery 107 is high, and to maintain the operation of the third voltage conversion circuit 111 by the second voltage conversion circuit 108 when the output voltage of the battery 107 drops.

[0027] The third voltage conversion circuit 111 converts an input voltage within an allowable range into one or more output voltages required for the operation of various circuits included in the downstream load 120. The third voltage conversion circuit 111 may be, for example, a switching DC-DC converter. Although the imaging circuit 113 and the CPU 114 are shown in FIG. 1 as circuits included in the load 120, these are merely examples. Note that the power supply control circuit 112 may also be included in the load 120.

[0028] The imaging circuit 113 converts a subject image formed by an imaging optical system of the imaging device 101, such as an imaging element, into an electrical signal or data for each pixel. The CPU 114 performs overall control of the imaging device 101 by loading a program stored in the ROM into the RAM and executing it.

[0029] The power supply control circuit 112 is, for example, a one-chip microcomputer incorporating a CPU, a ROM, and a RAM. The power supply control circuit 112 controls the operations of the power receiving circuit 103, the first voltage conversion circuit 104, the second voltage conversion circuit 108, the third voltage conversion circuit 111, and the third switch 110. The power supply control circuit 112 also has a function of executing operations according to the standard to which the interface 102 complies, such as detecting whether an external device is connected to the interface 102 and communicating with the external device.

[0030] Next, the specific operations of the above-mentioned components will be described with further reference to FIG. 2 and FIG. 3. In the following description, The external power supply 200 is a source device that complies with the USB Power Delivery standard (hereinafter referred to as the USB PD standard) and is capable of supplying 27 W (9.0 V, 3.0 A). The allowable input voltage of the third voltage conversion circuit 111 is 2.5V to 5.5V. The output voltage of battery 107 is 5.0V. The output voltage of the first voltage conversion circuit 104 is half the input voltage. The initial setting of the output voltage of the second voltage conversion circuit 108 is 2.6V. The imaging device 101 is a sink device that complies with the USB PD standard (the interface 102 is a USB interface that complies with the USB PD standard) For convenience, it is assumed that the voltage conversion efficiency of each voltage conversion circuit is 100%.

[0031] Fig. 2 is a flowchart relating to the operation of the power supply control circuit 112 in this embodiment, and Fig. 3 is a timing chart corresponding to Fig. 2. Note that A to F in Fig. 2 and Fig. 3 respectively indicate corresponding timings.

[0032] The operation shown in Fig. 2 is realized by, for example, a CPU included in the power supply control circuit 112, which is a one-chip microcomputer, loading a program stored in an internal ROM into an internal RAM and executing it. The operation shown in Fig. 2 is started in a state in which the external power supply 200 is not connected to the interface 102 and the imaging device 101 is operating using power from the battery 107. In this state, the third switch 110 is ON, and the output voltage of the battery 107 is input to both the first voltage conversion circuit 104 and the second voltage conversion circuit 108.

[0033] The set value of the output voltage of the second voltage conversion circuit 108 is set to a value that does not fall below the lower limit 2.5V of the allowable input voltage of the third voltage conversion circuit 111 even if a voltage drop occurs due to an increase in current when the power consumption of the load 120 increases. Here, it is set to 2.6V, but it may be a higher value. However, if the set value is increased, the available capacity of the battery 107 decreases, so it is better to set it to a low value from the viewpoint of effective use of the battery 107. In addition, the voltage conversion efficiency of the switching DC-DC converter is improved when the difference between the input voltage and the output voltage is small. In this embodiment, the output voltage of the third voltage conversion circuit 111 is low, about 0.5 to 1.1V. Therefore, from the viewpoint of the voltage conversion efficiency of the third voltage conversion circuit 111, the set value of the output voltage of the second voltage conversion circuit 108 is also low.

[0034] Here, since the voltage of the battery 107 at the start of operation has dropped to 5.0 V, the output voltage of the first voltage conversion circuit 104 is 2.5 V (5.0 V / 2). On the other hand, the output voltage of the second voltage conversion circuit 108 is 2.6 V. Therefore, the output voltage of the second voltage conversion circuit 108, 2.6 V (>2.5 V), is input to the third voltage conversion circuit 111.

[0035] In S201, the power supply control circuit 112 determines whether or not an external device is connected to the interface 102. If it is determined that an external device is connected, S202 is executed, and if not, S201 is executed, for example, after a certain time has elapsed. The determination can be made in a manner according to the standard to which the interface 102 complies. In the case of a USB interface, it is possible to determine whether or not an external device is connected based on the voltage at the power supply terminal of the interface 102. When an external device is connected (time t1 in FIG. 3, timing A), the voltage at the power supply terminal of the interface 102 becomes 5.0 V in accordance with the USB standard.

[0036] When it is detected that an external device is connected to the interface 102, the power supply control circuit 112 performs communication with the connected external device via the interface 102 according to the standard. Through this communication, the power supply control circuit 112 acquires information on the type and capability of the external device (external power supply 200). As a result, the power supply control circuit 112 recognizes that the external power supply 200 connected to the interface 102 is a source device that complies with the USB PD standard and has a power supply capability of 27 W (9.0 V, 3.0 A). It is assumed that the power requested from the external device is set in the power supply control circuit 112 in advance. In this embodiment, the power supply control circuit 112 requests the external power supply 200 to supply a voltage higher than the voltage of the battery 107, out of the power supply capability of the external power supply 200.

[0037] In S202, the power supply control circuit 112 changes the set value of the output voltage of the second voltage conversion circuit 108 (time t2 in FIG. 3, timing B). Specifically, the power supply control circuit 112 changes the set value of the output voltage of the second voltage conversion circuit 108 to a value that is greater than the current value and smaller than the output voltage of the first voltage conversion circuit 104 based on the voltage required of the external power supply 200 connected to the interface 102.

[0038] In this example, a power supply of 27 W (9.0 V, 3.0 A) is requested from external power source 200, and therefore the output voltage of first voltage conversion circuit 104 based on the requested power is 4.5 V. Therefore, power supply control circuit 112 changes the set value of the output voltage of second voltage conversion circuit 108 to a value (first voltage) that is greater than 2.6 V and a predetermined voltage lower than 4.5 V, for example, approximately 0.1 V to 0.2 V lower. Here, as an example, it is assumed that power supply control circuit 112 changes the set value of the output voltage of second voltage conversion circuit 108 to 4.4 V.

[0039] The reason for changing the set value of the output voltage of the second voltage conversion circuit 108 is to suppress a large fluctuation in the input voltage of the third voltage conversion circuit 111 when the power supply means is switched from the battery 107 to the external power source 200. For example, when the external power source 200 is connected to the interface 102 and 9V, which is a voltage required for the external power source 200, is supplied from the external power source 200, this voltage of 9V is output to the first voltage conversion circuit 104 via the power receiving circuit 103. Then, an output voltage of 4.5V, which is 1 / 2 of 9V, is output from the first voltage conversion circuit 102. Therefore, when the external power source 200 is connected in a state where the voltage of the battery 107 has dropped to nearly 5.0V, the voltage input to the third voltage conversion circuit 111 rises rapidly from 2.6V from the second voltage conversion circuit 108 to 4.5V from the first voltage conversion circuit 104. A sudden change in the input voltage may cause the output voltage of the third voltage conversion circuit 111 to fluctuate, and may affect the operation of the circuits included in the load 120.

[0040] The second voltage conversion circuit 108 takes a longer time until a change in the set value (change in the input voltage) is reflected in the output voltage than the first voltage conversion circuit 104, which is a switched capacitor converter. Alternatively, the second voltage conversion circuit 108 can control the time until a change in the set value is reflected in the output voltage by setting a slew rate or the like. Before switching the power supply means from the battery 107 to the external power supply 200, the output voltage of the second voltage conversion circuit 108 is gradually increased (for example, in a period of about 1 ms). This makes it possible to suppress fluctuations in the input voltage of the third voltage conversion circuit 111 that occur when power supply from the external power supply 200 is switched over.

[0041] Basically, the time it takes for the output voltage of the second voltage conversion circuit 108 to reach 4.4V from 2.6V is set to be longer than the time it takes for the output voltage to reach 4.5V after power is applied to the first voltage conversion circuit 104 from the external power source 200.

[0042] Note that instead of changing the set value of the output voltage of the second voltage conversion circuit 108 to 4.4 V at once, the set value may be changed stepwise from 2.6 V to 4.4 V. The set value may also be changed to a lower value, such as 4.0 V.

[0043] 3, after the output voltage of the second voltage conversion circuit 108 becomes 4.4V according to the changed set value, the power supply control circuit 112 executes S203 (time t4, timing C in FIG. 3). In S203, the power supply control circuit 112 turns off the third switch 110. Note that if the voltage of the battery 107 at time t3 is higher than 5.2V, the input to the third voltage conversion circuit 111 switches from the output of the first voltage conversion circuit 104 to the output voltage (4.4V) of the second voltage conversion circuit 108 between times t3 and t4.

[0044] In S204, the power supply control circuit 112 requests the external power supply 200 to supply 27 W (9.0 V, 3.0 A) through the interface 102. This causes the external power supply 200 to start supplying power in response to the request (t5 in FIG. 3, timing D). Note that if the output of the power receiving circuit 103 has been set to disabled, the power supply control circuit 112 sets the output of the power receiving circuit 103 to enabled at this timing.

[0045] When the output voltage of the power receiving circuit 103 exceeds 8.8V at time t6, the output voltage of the first voltage conversion circuit 104 becomes higher than 4.4V and starts to be input to the third voltage conversion circuit 111. Then, at time t7, the output of the power receiving circuit 103 reaches 9.0V, and the output voltage of the first voltage conversion circuit 104 reaches 4.5V.

[0046] Thereafter, for example, at time t8, when the power consumption of the load 120 exceeds 27 W, the power receiving circuit 103 limits the current to 3.0 A, and the output voltage of the first voltage conversion circuit 104 decreases. When the output voltage of the first voltage conversion circuit 104 falls below 4.4 V, the output voltage of the second voltage conversion circuit 108, 4.4 V, is input to the third voltage conversion circuit 111.

[0047] When the power consumption of load 120 falls below 27 W at time t9, the output voltage of first voltage conversion circuit 104 returns to 4.5 V, and the output voltage of 4.5 V from first voltage conversion circuit 104 is input to third voltage conversion circuit 111. In this way, even if the power consumption of load 120 exceeds the power supplied from external power supply 200 via interface 102, the input voltage of third voltage conversion circuit 111 can be maintained in the range of 4.4 V to 4.5 V by using the power of battery 107.

[0048] In S205, the power supply control circuit 112 determines whether or not the connected external device (external power supply 200) has been disconnected from the interface 102. If it is determined that the external device has been disconnected, S206 is executed, and if not, S205 is executed, for example, after a certain period of time. When the external device is disconnected from the interface 102 (time t10 in FIG. 3, timing E), the voltage of the power supply terminal of the interface 102 changes to 0V.

[0049] As a result, the output voltage of the first voltage conversion circuit 104 becomes 0V, and the output voltage of the second voltage conversion circuit 108 , 4.4V, is input to the third voltage conversion circuit 111 .

[0050] In S206, the power supply control circuit 112 turns on the third switch 110. As a result, the output voltage of the battery 107 is also input to the first voltage conversion circuit 104. However, even if the battery 107 is fully charged, the output voltage of the first voltage conversion circuit 104 is 4.2 V, so the output voltage of 4.4 V from the second voltage conversion circuit 108 continues to be supplied to the third voltage conversion circuit 111.

[0051] Furthermore, the power supply control circuit 112 changes the setting value of the output voltage of the second voltage conversion circuit 108 from 4.4V to 2.6V (t11, timing F in FIG. 3). If necessary, the power supply control circuit 112 may change the setting of the second voltage conversion circuit 108 so that the output voltage of the second voltage conversion circuit 108 drops gradually (for example, over a period of about 1 ms). Note that instead of changing the setting value of the output voltage of the second voltage conversion circuit 108 from 4.4V to 2.6V in one go, the setting value may be changed in stages from 4.4V to 2.6V.

[0052] 3, the output voltage of the second voltage conversion circuit 108 becomes 2.6 V. If the voltage of the battery 107 at time t11 is higher than 5.2 V, the input to the third voltage conversion circuit 111 switches from the output of the second voltage conversion circuit 108 to the output voltage of the first voltage conversion circuit 104 between times t11 and t12.

[0053] As described above, according to this embodiment, when switching the power supply means, the voltage supplied by the current power supply means is changed before switching the power supply means so that a large fluctuation in the supply voltage does not occur. Therefore, even if there is a large difference in the voltage of the power supply means before and after switching, it is possible to suppress malfunctions of the device.

[0054] (Other embodiments) If the change in the input voltage of the third voltage conversion circuit 111 is sufficiently small even when the power supply means is switched from the battery 107 to the external power supply 200 (for example, if the voltage of the battery 107 is equal to or higher than a threshold value), the operations of S202 and S203 may be skipped.

[0055] The disclosure of the present embodiment includes the following electronic device, a control method for the electronic device, and a program. (Item 1) An electronic device capable of switching a power supply means to be used, a first voltage conversion means for converting an input voltage from a first power supply means or a second power supply means into an output voltage, the output voltage being 1 / n (n is an integer of 2 or more) of the input voltage; a second voltage conversion means for converting an input voltage from the second power supply means into a set output voltage; a third voltage conversion means for converting the higher of the output voltage of the first voltage conversion means and the output voltage of the second voltage conversion means and supplying the converted voltage to a load; A control means for controlling an operation of the second voltage conversion means, The control means when the input voltage from the first power supply means is supplied to the first voltage conversion means, the setting is performed so that the output voltage of the second voltage conversion means becomes a first voltage that is close to the output voltage of the first voltage conversion means when the voltage from the first power supply means is input to the first voltage conversion means; and performing control to supply an input voltage from the first power supply means to the first voltage conversion means after performing the setting so that the output voltage of the second voltage conversion means becomes the first voltage. (Item 2) An interface for connecting an external power supply; 2. The electronic device according to item 1, wherein the first power supply means is an external power supply connected to the interface, and the second power supply means is a battery. (Item 3) The electronic device described in item 2, characterized in that the control means performs control so as to supply the output voltage of the second power supply means to the first voltage conversion means when the first power supply means is not connected to the interface. (Item 4) The power supply circuit further includes a switch means provided between the second power supply means and the first voltage conversion means, The electronic device described in item 2 or 3, characterized in that the control means turns the switch means ON when the first power supply means is not connected to the interface, and turns the switch means OFF when the first power supply means is connected to the interface. (Item 5) 5. The electronic device according to any one of items 1 to 4, wherein the voltage conversion efficiency of the first power supply means is higher than the voltage conversion efficiency of the second power supply means. (Item 6) 6. The electronic device according to item 5, wherein the first power supply means is a switched capacitor converter. (Item 7) 7. The electronic device according to any one of items 1 to 6, wherein an input voltage from the first power supply means is higher than an input voltage from the second power supply means. (Item 8) The electronic device according to any one of claims 1 to 7, characterized in that the control means changes the output voltage setting of the second voltage conversion means to the first voltage by gradually changing the output voltage setting of the second voltage conversion means. (Item 9) The electronic device described in any one of items 1 to 8, characterized in that the control means controls the second voltage conversion means so that the time from when the first voltage conversion means is supplied with the input voltage from the first power supply means until the output voltage of the second voltage conversion means changes from a current output voltage to the first voltage is longer than the time from when the first voltage conversion means is supplied with the input voltage from the first power supply means until the output voltage of the first voltage conversion means changes to a value corresponding to the input voltage from the first power supply means. (Item 10) The electronic device described in item 2, characterized in that when the external power source is not connected to the interface, the control means controls the output voltage of the second voltage conversion means to be a second voltage that is higher by a predetermined value than the lower limit of the operable voltage of the third voltage conversion means, and when the external power source is connected to the interface, the control means controls the second voltage conversion means so that the output voltage of the second voltage conversion means changes from the second voltage to the first voltage. (Item 11) The electronic device described in item 10, characterized in that the interface receives power from the external power source in accordance with the USB Power Delivery standard, and the control means controls the interface to request a voltage from the external power source that is higher than the fully charged voltage of the battery. (Item 12) 12. The electronic device according to item 11, wherein the control means controls the external power source to request the higher voltage after the output voltage of the second voltage conversion means becomes the first voltage. (Item 13) 13. The electronic device according to item 12, wherein the first voltage is a voltage that is lower than 1 / n of the input voltage from the first power supply means by a predetermined voltage. (Item 14) a first voltage conversion means for converting an input voltage from a first power supply means or a second power supply means into an output voltage, the output voltage being 1 / n (n is an integer of 2 or more) of the input voltage; a second voltage conversion means for converting an input voltage from the second power supply means into a set output voltage; a third voltage conversion means for converting the higher of the output voltage of the first voltage conversion means and the output voltage of the second voltage conversion means and supplying the converted voltage to a load; a control means for controlling an operation of the second voltage conversion means, the control method being executed by an electronic device capable of switching a power supply means to be used, the control method comprising: performing the setting so that, when an input voltage from the first power supply means is supplied to the first voltage conversion means, an output voltage of the second voltage conversion means becomes a first voltage that is close to an output voltage of the first voltage conversion means when a voltage from the first power supply means is input to the first voltage conversion means; and performing control to supply an input voltage from the first power supply means to the first voltage conversion means after performing the setting so that an output voltage of the second voltage conversion means becomes the first voltage. (Item 15) A program for causing a computer to function as a control means possessed by the electronic device according to any one of items 1 to 13.

[0056] The present invention can also be realized by a process in which a program for implementing one or more of the functions of the above-described embodiments is supplied to a system or device via a network or a storage medium, and one or more processors in a computer of the system or device read and execute the program. The present invention can also be realized by a circuit (e.g., ASIC) that implements one or more of the functions. [Explanation of symbols]

[0057] Reference Signs List 101: imaging device, 102: interface, 103: power receiving circuit, 104: first voltage conversion circuit, 106: first switch, 107: battery, 108: second voltage conversion circuit, 109: second switch, 110: third switch, 111: third voltage conversion circuit, 112: power supply control circuit

Claims

1. An electronic device capable of switching the power supply means used, A first voltage conversion means that converts an input voltage from a first power supply means or a second power supply means into an output voltage, wherein the output voltage is 1 / n of the input voltage (where n is an integer of 2 or more), A second voltage conversion means that converts the input voltage from the second power supply means into a set output voltage, A third voltage conversion means converts the higher of the output voltage of the first voltage conversion means and the output voltage of the second voltage conversion means and supplies it to the load, The system includes a control means for controlling the operation of the second voltage conversion means, The control means is When supplying the input voltage from the first power supply means to the first voltage conversion means, the output voltage of the second voltage conversion means is set to a first voltage lower than 1 / n of the input voltage from the first power supply means. An electronic device characterized by performing control to supply an input voltage from the first power supply means to the first voltage conversion means after setting the output voltage of the second voltage conversion means to the first voltage.

2. The electronic device according to claim 1, characterized in that the first power supply means is an external power supply that can be connected to the electronic device, and the second power supply means is a battery inside the electronic device.

3. The electronic device according to claim 1, characterized in that the control means supplies the output voltage of the second power supply means to the first voltage conversion means and the second voltage conversion means when the first power supply means is not connected to the electronic device, and when it is detected that the first power supply means is connected to the electronic device, it supplies the input voltage from the second power supply means to the second voltage conversion means and controls the input voltage of the first voltage conversion means to switch from the input voltage from the second power supply means to the input voltage from the first power supply means.

4. The system further includes a switch means provided between the second power supply means and the first voltage conversion means, The electronic device according to claim 1, characterized in that the control means turns on the switch means when the first power supply means is not connected to the electronic device, and turns off the switch means when the first power supply means is connected to the electronic device.

5. The electronic device according to claim 1, characterized in that the control means controls the output voltage of the second voltage conversion means to be a second voltage that is a predetermined value higher than the lower limit of the operable voltage of the third voltage conversion means when the first power supply means is not connected to the electronic device, and controls the second voltage conversion means to change the output voltage of the second voltage conversion means from the second voltage to the first voltage when the first power supply means is connected to the electronic device.

6. The electronic device according to claim 2, wherein the electronic device receives power from the first power supply means in accordance with the USB Power Delivery standard, and the control means controls the first power supply means to request a voltage higher than the voltage of the fully charged battery.

7. The electronic device according to claim 6, characterized in that the control means controls the first power supply means to request the high voltage after the output voltage of the second voltage conversion means becomes the first voltage.

8. The electronic device according to claim 7, characterized in that the first voltage is a voltage that is lower by a predetermined voltage than 1 / n of the input voltage from the first power supply means.

9. The electronic device according to claim 1, characterized in that the voltage conversion efficiency of the first power supply means is higher than the voltage conversion efficiency of the second power supply means.

10. The electronic device according to claim 9, characterized in that the first power supply means is a switched-capacitor converter.

11. The electronic device according to claim 1, characterized in that the input voltage from the first power supply means is higher than the input voltage from the second power supply means.

12. The electronic device according to claim 1, characterized in that the control means changes the output voltage of the second voltage conversion means to the first voltage by gradually changing the setting of the output voltage of the second voltage conversion means.

13. The electronic device according to claim 1, characterized in that the control means controls the second voltage conversion means such that the time it takes for the output voltage of the second voltage conversion means to change from the current output voltage to the first voltage is longer than the time it takes from when the input voltage from the first power supply means is supplied to the first voltage conversion means until the output voltage of the first voltage conversion means becomes 1 / n of the input voltage from the first power supply means.

14. A first voltage conversion means that converts an input voltage from a first power supply means or a second power supply means into an output voltage, wherein the output voltage is 1 / n of the input voltage (where n is an integer of 2 or more), A second voltage conversion means that converts the input voltage from the second power supply means into a set output voltage, A third voltage conversion means converts the higher of the output voltage of the first voltage conversion means and the output voltage of the second voltage conversion means and supplies it to the load, A control method performed by an electronic device having control means for controlling the operation of the second voltage conversion means, and capable of switching the power supply means used, When supplying the input voltage from the first power supply means to the first voltage conversion means, the output voltage of the second voltage conversion means is set to a first voltage lower than 1 / n of the input voltage from the first power supply means, After setting the output voltage of the second voltage conversion means to the first voltage, control is performed to supply the input voltage from the first power supply means to the first voltage conversion means, A method for controlling electronic equipment, characterized by having the following features.

15. A program for causing a computer to function as a control means of an electronic device according to any one of claims 1 to 13.

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