JP2018107552A - Camera system - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a camera system in which a residual relation of a plurality of batteries mounted to a battery grip is not imbalanced as much as possible.SOLUTION: A camera system includes: a battery grip including a selection part which can be mounted to a camera, in which two batteries can be loaded, in which a battery voltage of the batteries can be compared by a comparator, and selects one battery from the two batteries; and a camera capable of charging the battery loaded to the battery grip in a state where the battery grip is mounted. Before the start of the charging of the battery, a battery mounting detection part detects a loading state of the battery loaded to the battery grip. When it is detected that a whole battery is loaded, the selection part controls the selection of the battery of which a battery voltage is the lowest.SELECTED DRAWING: Figure 1

Description

  The present invention relates to a camera system capable of charging a plurality of secondary batteries mounted on a battery grip.

  A rechargeable secondary battery is used as a battery as a power source for the camera. In addition, a lithium ion battery having many advantages such as a long cycle life and high energy density is used for this battery. In a conventional camera system, it is necessary to use a dedicated charger to charge the secondary battery. In order to use the camera for a longer time, there is a hassle of carrying a replacement battery or a charger.

  As one of the solutions, a camera system equipped with a battery grip capable of mounting a plurality of batteries is known. The plurality of batteries attached to the battery grip has a high battery voltage by comparing the battery voltages so that the remaining battery amount can be reduced substantially evenly without reducing the plurality of batteries attached as in Patent Document 1. The battery is controlled to be selected.

  In addition, a system for charging a plurality of batteries mounted on a battery grip from a commercial power source or the like via a camera body has been disclosed recently (Patent Document 2). The charge control feature of this system is that test charging is performed for a plurality of batteries mounted on the battery grip, the discharge current of each battery is acquired by the control unit of the camera body, and a battery with a higher discharge current is selected as a charging target. It is controlled to do.

  Such a battery grip has a small arrangement area of connection terminals between the battery grip and the camera, has a limited number of connection terminals that can be arranged, and is required to provide a more inexpensive battery grip to the user. The configuration should be simplified.

  In addition, as described above, when power is supplied from the battery grip to the camera, it is preferable to control the battery selection so that the remaining amount of the battery is reduced substantially evenly without reducing the plurality of batteries attached to the battery grip. . If the battery is used in such a way that the installed battery is reduced, there may be a case where the supply source is switched from a battery that has been used to the limit to a battery that has sufficient battery voltage. For example, when this switching timing is encountered during the operation of the camera, it may cause a deviation in accuracy such as a deviation in control such as mechanical braking due to a sudden voltage fluctuation, or a factor causing a malfunction, which is not preferable.

  Therefore, when charging the battery, it is preferable to charge the battery while making the remaining battery level of the attached battery substantially equal, assuming that the camera is used with the charging interrupted. For this purpose, it is necessary to select a battery having a smaller remaining battery capacity when charging a plurality of batteries mounted on the battery grip.

Japanese Patent Laid-Open No. 9-80580 JP2013-102625A

  However, in Patent Document 2, in order to select the battery to be charged based on the measurement result of the charging current at the time of test charging, if one of the plurality of batteries attached to the battery grip is in an overdischarged state, the remaining battery level However, the charging current during test charging is low. As a result, the battery with the more remaining battery charge is charged, and the relationship between the remaining battery levels of the plurality of batteries attached to the battery grip becomes unbalanced.

  Therefore, an object of the present invention is to prevent an unbalanced relationship between the remaining amounts of a plurality of batteries attached to a battery grip as much as possible.

  In order to achieve the above object, the camera system according to the present invention can be mounted on a camera, can be loaded with two batteries, and the battery voltages of these batteries are compared by a comparator to compare the two batteries. A battery grip having a selection unit for selecting one of the batteries, and a camera capable of charging the battery loaded in the battery grip with the battery grip attached. Before starting charging, detection is performed by a battery attachment detection unit that detects the loading state of the battery loaded in the battery grip, and when it is detected that all the batteries are loaded, the selection unit Control is performed to select the battery having the lowest voltage.

  According to the present invention, the relationship between the remaining amounts of a plurality of batteries mounted on the battery grip can be prevented from being unbalanced as much as possible.

2 is a block diagram for explaining an example of a configuration of a camera system in Embodiment 1. FIG. 3 is a flowchart illustrating a battery charging operation 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.

  FIG. 1 is a block diagram for explaining an example of the configuration of a camera system according to the first embodiment. In FIG. 1, 10 is a camera body (hereinafter referred to as a camera), 20 is a battery grip, and 30 is a USB charger. First, the USB charger 30 rectifies the input commercial power supply 40 with a rectifier circuit (not shown), and outputs a DC voltage converted to a predetermined value to the camera 10 via the USB terminal 17.

  Next, the inside of the camera 10 will be described. Reference numeral 11 denotes a microcomputer for performing camera operation control and secondary battery charging control. Reference numeral 12 denotes a DCDC converter (hereinafter referred to as DC / DC), which inputs a voltage from a power supply path according to the connection state of the charger 30 and converts it into a voltage suitable for a microcomputer 11 and a circuit (not shown) inside the camera 10. And output.

  When the charger 30 is not connected to the camera 10, the power input of the DC / DC 12 is an output of a secondary battery (hereinafter referred to as a battery) 21 or 22. At this time, the microcomputer 11 controls the power supply line of the battery grip 20 and the DC / DC 12 to be connected with the switch 15 short-circuited and the switch 14 open.

  On the other hand, when the charger 30 connected to the commercial power source 40 is connected to the camera 10, an output (not shown) obtained by further converting the DC voltage input from the charger 30 into a predetermined voltage in the charge control circuit. It is. At this time, the microcomputer 11 performs control so that the connection between the battery grip 20 and the DC / DC 12 is cut off by opening the switch 15 and shorting the switch 14.

  When the microcomputer 11 detects that the USB charger 30 connected to the commercial power source 40 is connected to the camera, the microcomputer 11 short-circuits the switch 14 and opens the switch 15. When the switch 14 is short-circuited, the charging voltage line output from the charging control circuit and the power line of the battery grip 20 are connected. Further, when the switch 15 is opened, the connection between the power line of the battery grip 20 and the DC / DC 12 is cut off, and the input power of the DC / DC 12 becomes a voltage generated in the charge control circuit.

  In the charging control according to the first embodiment, constant current charging (hereinafter referred to as CC charging) or constant voltage charging (hereinafter referred to as CV charging) is performed according to the battery voltage of the battery 21 or 22 to be charged. A constant voltage circuit and a constant current circuit are provided (both not shown). In addition, the charge system regarding Embodiment 1 may be other than the constant current constant voltage control system.

  The microcomputer 11 performs CC charging until the battery voltage of the battery 21 or 22 to be charged reaches a predetermined voltage, and controls to switch to CV charging when the voltage reaches the predetermined voltage. In addition, the constant voltage circuit generates an output voltage from the USB charger so that the battery can be charged and is within the allowable input range to the DC / DC 12. The constant current circuit can switch the current value according to the battery voltage of the battery 21 or 22 to be charged, and this switching is controlled by the microcomputer 11.

  14 and 15 are switches, and the microcomputer 11 controls each state according to the connection state of the charger 30. When the charger 30 is not connected to the camera 10, the switch 15 is short-circuited to connect the DC / DC 12 to the power line of the battery grip 20 in order to supply power from the battery attached to the battery grip 20. Further, since there is no need to connect the power line of the battery grip 20 and the charge control circuit 13, the switch 14 is opened.

  When the charger 30 connected to the commercial power source 40 is connected to the camera 10, the microcomputer 11 controls the battery charging, so that the microcomputer 11 connects the power supply line of the battery grip 20 and the charging control circuit 13. Shorts switch 14. Also, since the DC / DC 12 input power supply during battery charging control is a constant voltage circuit output in the charging control circuit 13, the microcomputer 11 opens the switch 15 and shuts off the power line of the battery grip 20 and the DC / DC 12. To do. However, when the batteries 21 and 22 are not attached to the battery grip 20, since the battery cannot be charged, the microcomputer 11 controls the switch 14 to be opened.

  Reference numeral 16 denotes an attachment detection unit for detecting the battery attachment state of the battery grip 20 and can detect four states: attachment of both batteries, attachment of only the battery 21, attachment of only the battery 22, and non-attachment of both batteries. Two signals are input to the attachment detection unit 16 from the battery grip 20, and each signal is pulled up in the camera 10. When the battery 21 is attached to the battery grip, the mechanical contact 51 in the magazine 50 comes into contact with GND and outputs “L” from the terminal 5k. This signal is input to the attachment detection 16 via the terminals 2k, 2b, and 1b. When the battery 21 is not attached, the mechanical contact 51 is disconnected from the GND, so that the terminal 5k becomes high impedance (open), and “H” from the pull-up resistor is input to the attachment detection unit 16.

  Similarly, when the battery 22 is mounted, the mechanical contact 52 in the magazine 50 comes into contact with GND and outputs “L” from the terminal 5m. This signal is input to the attachment detection 16 via the terminals 2m, 2c, and 1c. When the battery 22 is not attached, the mechanical contact 52 is disconnected from the GND, so that the terminal 5m becomes high impedance (open), and “H” from the pull-up resistor is input to the attachment detection unit 16. Further, when the camera 10 is in the battery charging operation state, when the microcomputer 11 detects that both batteries are not attached, the switch 14 is turned on for a period until any battery is attached to the battery grip 20. Open.

  Next, the inside of the battery grip 20 will be described. 21 and 22 are secondary batteries. Each battery has a voltage output, a GND, a battery information input / output terminal, a battery cell (not shown), a battery microcomputer, and a memory. The batteries 21 and 22 are not directly attached to the battery grip 20 but are attached to the magazine 50 and the magazine 50 is set on the battery grip 20.

  When the battery 21 is mounted on the magazine 50, the mechanical contact 51 comes into contact with a GND level member in the magazine 50, and the "L" level is output from the terminal 5k. Similarly, when the battery 22 is mounted on the magazine 50, the mechanical contact 52 comes into contact with the GND level member in the magazine 50, and the "L" level is output from the terminal 5m.

  When the magazine 50 is set on the battery grip 20, the output of the terminal 5k is input to the mounting detection unit 16 via the terminals 2k, 2b, and 1b, and the output of the terminal 5m is input via the terminals 2m, 2c, and 1c, respectively. The voltage output of the battery 21 is supplied to the terminal of the switch 23 via the terminals 5f and 2f and the negative input of the comparator 25, the GND is supplied to the GND of the camera 10 via the terminals 5n, 2n, 2d and 1d. The terminals are connected to the terminals of the switch 28 via the terminals 5g and 2g, respectively.

  Similarly, the voltage output of the battery 22 is supplied to the terminal of the switch 24 and the plus input of the comparator 25 via the terminals 5h and 2h, and GND is supplied to the GND of the camera 10 via the terminals 5n, 2n, 2d and 1d. Input / output is connected to the terminal of the switch 29 via terminals 5j and 2j, respectively.

  Here, the information output from the battery information input / output is at least the remaining amount of the battery, and is output in the form of a voltage value or a percentage of the remaining amount. In addition, information such as temperature information inside the battery and the degree of deterioration is also output. The battery information input / output of each of the batteries 21 and 22 is connected to the microcomputer 11 via the switches 28 and 29 and the terminals 2e and 1e. The microcomputer 11 acquires various pieces of battery information of the battery 21 or the battery 22 from a battery microcomputer (not shown) inside each of the batteries 21 and 22 by using communication means such as UART communication.

  Reference numerals 23 and 24 denote switches. One terminal of the switch 23 is connected to the voltage output of the battery 21, and one terminal of the switch 24 is connected to the voltage output of the battery 22. At one terminal, the switches 23 and 24 are common (short circuit). The switches 23 and 24 are configured such that one of them is short-circuited according to a predetermined condition, and is connected to the camera 10 via the terminals 2a and 1a.

  In other words, when either one of these switches is in a short-circuit state, the battery is selected for power supply or battery charging. The switches 23 and 24 are controlled by a control signal. In the first embodiment, when the control signal is “L”, the switch is short-circuited, and when the control signal is “H”, the switch is open. This control signal corresponds to CMP1 which is the XNOR26 output in the switch 23, and CMP2 which is the inverted signal of CMP1 in the switch 24.

  When the charger 30 is not connected to the camera 10, that is, when the battery output of the battery 21 or 22 is supplied to the camera 10, the switch connected to the battery having the higher battery voltage is short-circuited. The switch is opened. That is, when power is supplied to the camera 10, the battery with the higher battery voltage is selected.

  Further, when the charger 30 connected to the commercial power source 40 is connected to the camera 10, that is, during the battery charging operation, the switch connected to the battery with the lower battery voltage is short-circuited, and one switch is It becomes an open state. That is, when charging the battery, the battery with the lower battery voltage is selected. The comparison of the voltages of the batteries 21 and 22 is performed by the comparator 25. If the output voltage of each battery is battery 21> battery 22, the output CMP0 of the comparator 25 is “L”, otherwise “H”. Is output.

  An XNOR circuit 26 is a logic circuit. One side of the input of the XNOR circuit 26 is connected to the output CMP0 of the comparator 25, and the other input is connected to the output (Smode) of the microcomputer 11 via the terminals 2b and 1b. The output (Smode) of the microcomputer 11 is a signal that the microcomputer 11 outputs according to the presence / absence of the battery charging operation and the battery mounting state. In the first embodiment, when the battery charging operation is performed, all the batteries are If it is in the mounted state, “L” is output, otherwise “H” is output.

  Thus, when the output (CMP1) of the XNOR circuit 26 outputs “L”, control is performed so as to select the battery having the lower battery voltage. For example, when the battery voltage is battery 21 <battery 22, since CMP0: H, Smode: L, CMP1: L, which is an XNOR output, switches 23 are short-circuited, and battery 21 is connected to the camera via terminals 2a and 1a. 10 is selected as a battery charging target.

  On the other hand, when battery 21> battery 22, because CMP0: L and Smode: L, CMP1: H and CMP1 output CMP2: L of CMP1 are input. The result switch 24 is short-circuited, the battery 22 is connected to the camera 10 via the terminals 2a and 1a, and is selected as a battery charging target. Here, since the battery selection operation is performed in real time with the battery voltages of a plurality of batteries, if the battery voltage of the selected battery to be charged exceeds the battery voltage of the non-selection battery during the charging operation, the battery selection operation was a non-selection battery. The target battery is switched to the other battery.

  Reference numerals 28 and 29 denote switches set in a communication line between the battery and the microcomputer 11. One terminal of the switch 28 is used for battery information input / output of the battery 21, and one terminal of the switch 29 is used for battery information input / output of the battery 22. Each is connected. One terminal is commonly (short-circuited) with the switches 28 and 29. The switch 28 is controlled by the control signal CMP1, the switch 29 is controlled by the control signal CMP2, and one of the switches is short-circuited in conjunction with the battery selection. This is the configuration.

  Therefore, when the battery 21 is selected, the switch 28 is short-circuited and the switch 29 is opened. When the battery 22 is selected, the switch 28 is opened and the switch 29 is short-circuited. The common terminal side of the switches 28 and 29 is connected to the microcomputer 11 via the terminals 2e and 1e. Using this line, the microcomputer 11 transmits request communication to a battery microcomputer (not shown) inside a battery (hereinafter, selected battery) selected by communication such as UART, and acquires various pieces of battery information.

  Next, the operation when the charger 30 connected to the commercial power supply 40 is connected to the camera 10 will be described using the flowchart of FIG. FIG. 2 is a flowchart illustrating the operation during battery charging in the first embodiment. When the microcomputer 11 detects that the charger 30 connected to the commercial power supply 40 is connected to the camera 10, the microcomputer 11 opens the switch 15 in order to cut off the power supply from the battery 21 or 22 to the camera 10. (Step S201). Note that the power supply to the camera 10 at this time is the DC voltage generated by the charge control circuit 13 as described above.

  Next, the microcomputer 11 acquires the battery mounting state of the battery grip 20 from the mounting detection unit 16 (step S202). When the battery mounting state is “all not mounted”, the process proceeds to step S208, and a battery charging operation end process is performed. The description after step S208 will be described later. When the battery mounting state is “one battery is not mounted”, in step S211, the microcomputer 11 sets the control signal Smode necessary for battery selection to “H”. At this time, the selection condition for battery selection is to select the battery with the higher battery voltage, that is, the attached battery.

  When the battery mounting state is “all mounted”, the microcomputer 11 sets the control signal Smode necessary for battery selection to “L” (step S203). At this time, the battery selection condition is the lower battery voltage. In step S204, the microcomputer 11 acquires the battery voltage of the selected battery to be charged from the battery information output of the selected battery, and compares the acquired battery voltage with a predetermined voltage in order to determine the necessity of charging the selected battery. When the acquired battery voltage information is equal to or higher than the predetermined voltage, the selected battery and the non-selected battery do not need to be charged, so the process proceeds to step S208, and the battery charging operation is terminated. The description after step S208 will be described later.

  On the other hand, when the acquired battery voltage information is less than the predetermined voltage, it is necessary to charge the selected battery. Therefore, the microcomputer 11 sets the switch 14 in a short-circuited state and selects the selected battery in the charging control circuit 13 and the battery grip 20. Connect (step S205) and start charging (step S206). When the battery charging is started, the microcomputer 11 acquires the battery voltage from the battery information input / output of the selected battery, and determines the necessity of continuing the charging (step S207). When the acquired voltage has not reached the predetermined voltage, the same step is periodically repeated, and when it reaches the predetermined voltage, the process proceeds to step S208.

  Here, since the selected battery is charged in step S206, the battery voltage increases. Since the battery is selected in real time, when the battery voltage of the selected battery exceeds the battery voltage of the non-selected battery, the connection to the camera 10 can be switched using the non-selected battery as the battery to be charged.

  In step S208 and subsequent steps, switching from the battery grip 20 to the power supply to the camera 10 is performed, and the microcomputer 11 first opens the switch 14 in step S208 to select the battery selected by the charge control circuit 13 and the battery grip 20. Shut off. Next, in step S209, in order to change the state of the control signal Smode necessary for battery selection to the condition at the time of power feeding, “H” is set, and the battery selection condition is set to the higher battery voltage. Next, the microcomputer 11 short-circuits the switch 15 (step S210), connects the selected battery and the DC / DC 12, connects the selected battery to the camera 10, and ends the battery charging operation.

  As described above, according to the first embodiment, when charging a plurality of batteries mounted on the battery grip 20, the battery with the lower battery voltage is preferentially selected, so that the remaining battery level between the mounted batteries is uneven. Can be suppressed.

  In addition, this invention is not limited to the above-mentioned embodiment, A various deformation | transformation or change is possible within the range of the summary.

DESCRIPTION OF SYMBOLS 10 Camera 11 Control part 16 Battery mounting detection part 20 Battery grip 21, 21 Battery 25 Comparator 26, 27 Selection part

Claims (1)

A battery grip that can be mounted on a camera and that can be loaded with two batteries, and that has a selection unit that compares the battery voltages of these batteries with a comparator and selects one of the two batteries. When,
A battery capable of charging the battery loaded in the battery grip with the battery grip attached;
Before starting the charging of the battery, the battery mounting detection unit detects the loading state of the battery loaded in the battery grip, and when it is detected that all the batteries are loaded, the selection unit Controls to select the battery with the lowest battery voltage.