JP2015002068A - Electronic apparatus system, battery charger and electronic apparatus - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an electronic apparatus system allowing a battery charger to have a fail-safe function capable of finding an abnormality of a charge cable to improve a safety property for charging a secondary battery, the battery charger and an electronic apparatus.SOLUTION: An electronic apparatus system includes a battery charger 10, and an electronic apparatus 20. The battery charger 10 includes a power output unit 12, an impedance calculation unit 13, an output stop unit 14, and a charge cable K. The electronic apparatus 20 includes a terminal unit 30, and a secondary battery 40. The terminal unit 30 includes a shunt resistor 31, a current detection unit 32, a voltage detection unit 33, an information processing unit 34, and an electrical circuit 35, and has an internal load 36. The impedance calculation unit 13 calculates impedance Rof the charge cable K on the basis of a charge voltage value Vand a charge current value Iobtained from the power output unit 12, and a secondary battery charge current value I-Iand a secondary battery charge voltage value Vobtained from the information processing unit 34.

Description

  The present invention relates to an electronic device system, a charger, and an electronic device that can charge a secondary battery mounted on a portable terminal or the like.

  Electronic devices such as smartphones have been improved in performance and multifunction, and the capacity of secondary batteries used has increased (capacity increased), and the charging current has increased accordingly. Proposals have been made in which the performance of secondary batteries and the risk of heat generation are avoided (see, for example, Patent Documents 1 to 4).

  In Patent Document 1, a constant current stabilizing circuit, a constant voltage stabilizing circuit, a control unit, and the like are provided in a charger, and a thermal cutoff temperature based on the temperature of the secondary battery is provided for rapid charging of the secondary battery to generate heat of the battery. The risk due to is reduced.

  Patent Document 2 relates to a mobile terminal device, an authentication circuit, a built-in power supply that supplies power to the authentication circuit, and an authentication circuit that cuts off power supply from the external power supply to the terminal body while authenticating the external power supply. Power management means for supplying power to the power source. And the portable terminal main body can be protected by not using the external power source for authentication, and the power consumption of the built-in battery used for authentication can be reduced by supplying power only during the authentication period.

  In Patent Document 3, the power supply device includes a receiving unit that receives internal temperature data of the charging / discharging device, a temperature measuring unit that measures its own internal temperature, and power supplied to the charging / discharging device based on the temperature data. Power supply mode switching means for switching the power supply mode. And by measuring the temperature, the battery pack can be charged in an appropriate charging mode corresponding to the temperature condition, so charging due to overcurrent that occurs when charging the battery pack in a state that is not within the temperature appropriate range It is possible to suppress a decrease in capacity.

  Patent Document 4 relates to a battery charging device, and relates to a battery charging device. When the voltage value at both ends of the battery is smaller than the end-of-charge voltage value, charging control means for controlling the output of the charging power supply means so as to charge the battery at a required constant power value. It has. And a battery can be charged rapidly, the increase in the maximum required electric power which becomes a problem by constant current charge can be avoided, and the enlargement of a battery charging device can be prevented. In addition, the abnormality determination time and the abnormality determination current change amount are acquired, and charging including a battery or the like is performed depending on whether or not the change amount of the charging current value in the time longer than the abnormality determination time is smaller than the abnormality determination current change amount. The circuit abnormality is judged.

JP-A-8-308139 JP 2007-195021 A JP 2007-325500 A JP 2009-11068 A

  Although various proposals have been made with a function that takes into account safety during quick charging (see Patent Documents 1 to 4), abnormal values such as current and voltage are only detected. Even if these values are apparently normal, the charging cable that connects the charger and the electronic device may be in an abnormal state. The risk of charging and heat generation is increasing. However, no technology has been proposed that has a configuration for preventing these dangers.

  The present invention has been made in view of the above-mentioned reasons, and its purpose is to provide a fail-safe function capable of finding an abnormality of a charging cable directly or indirectly on the charger side, and safety of charging a secondary battery. It is an object of the present invention to provide an electronic device system, a charger, and an electronic device with improved performance.

  The electronic device system of the present invention is an electronic device system including an electronic device having a built-in secondary battery, a charger, and a charging cable for connecting the electronic device and the charger. A charging voltage is applied to the electronic device via the charging cable, and a charging current is supplied to the electronic device, and the electronic device charges the charging voltage to at least the secondary battery. And a voltage supplied to at least the secondary battery charging current and an internal load of the electronic device, the voltage being divided into a voltage drop generated in a circuit through which the secondary battery charging current supplied to the secondary battery flows. The electronic device transmits at least the value of the secondary battery charging voltage and the value of the secondary battery charging current to the charger, and the charger Also the value of the charging voltage, the value of the charging current, the value of the secondary battery charging voltage, based on the value of the secondary battery charging current, and calculates the impedance of the charging cable.

  As a variety of electronic device systems of the present invention, for example, the internal load is branched and connected from the electric circuit, and the secondary battery charging current is obtained by subtracting the load current from the charging current. The voltage drop is generated by the product of the secondary battery charging current and the shunt resistance provided in the electric circuit, and the charger stores the value of the shunt resistance.

  For example, the electronic device further includes a current detection unit that detects the secondary battery charging current using the shunt resistor.

For example, the charging voltage value is V _OUT , the charging current value is I _CHG , the secondary battery charging voltage value is V _BATT , and the load current value is I. _L, and the value of the shunt resistor when R _1, the charger by the following formula (1) to calculate the impedance R _CBL of the charging cable.

  For example, when the impedance of the charging cable is larger than a predetermined value, the charger stops applying the charging voltage and supplying the charging current.

  The electronic device system of the present invention is an electronic device system including an electronic device having a built-in secondary battery, a charger, and a charging cable for connecting the electronic device and the charger. A charging voltage is applied to the electronic device via the charging cable, and a charging current is supplied to the electronic device, and the electronic device charges the charging voltage to at least the secondary battery. And a voltage supplied to at least the secondary battery charging current and an internal load of the electronic device, the voltage being divided into a voltage drop generated in a circuit through which the secondary battery charging current supplied to the secondary battery flows. The electronic device transmits at least the value of the secondary battery charging voltage and the value of the drop voltage to the charger, and the charger The value of the electric voltage, the value of the charging current, the value of the secondary battery charging voltage, based on the value of the voltage drop to calculate the impedance of the charging cable.

  As a variety of electronic device systems of the present invention, for example, the internal load is branched and connected from the electric circuit, and the secondary battery charging current is obtained by subtracting the load current from the charging current. The voltage drop is generated by the product of the secondary battery charging current and the shunt resistance provided in the electric circuit.

  For example, the electronic device further includes a current detection unit that detects the secondary battery charging current using the shunt resistor.

For example, the charging voltage value is V _OUT , the charging current value is I _CHG , the secondary battery charging voltage value is V _BATT , and the load current value is I. _L , and when the shunt resistance value is R ₁ , the drop voltage value is V _DROP = R ₁ × (I _CHG −I _L ), and the charger is charged by the following equation (2). The cable impedance R _CBL is calculated.

  For example, when the impedance of the charging cable is larger than a predetermined value, the charger stops applying the charging voltage and supplying the charging current.

  The charger of the present invention is a charger capable of charging an electronic device having a built-in secondary battery, and receives a power supply from an external power source and outputs a charging voltage and a charging current suitable for the electronic device to be charged. A power output unit, a charging connection unit that is connectable to the electronic device via a charging cable, applies the charging voltage to the electronic device and supplies the charging current to the electronic device, and the electronic device. A signal connection unit for receiving at least a secondary battery charging voltage value for charging the secondary battery and a secondary battery charging current value to be supplied to the secondary battery, at least the charging voltage value, and the charging current. And an impedance calculator that calculates the impedance of the charging cable based on the value of the secondary battery charging voltage and the value of the secondary battery charging current.

For example, the electronic device may divide the charging voltage into at least the secondary battery charging voltage and a voltage drop generated in an electric circuit through which the secondary battery charging current flows, The charging current is divided into at least the secondary battery charging current and a load current supplied to the internal load of the electronic device, and the drop voltage is the shunt resistance provided in the secondary battery charging current and the electric circuit. The charger stores the value of the shunt resistor, the charging voltage value is V _OUT , the charging current value is I _CHG , and the secondary battery charging voltage value is V _BATT, the load current is _{I L,} when the value of the shunt resistor is _{R 1,} the impedance calculation unit by the following formula (1), the impedance of the charging cable _{R C} To calculate the _L.

  For example, when the impedance of the charging cable is larger than a predetermined value, the power output unit stops applying the charging voltage and supplying the charging current.

  The charger of the present invention is a charger capable of charging an electronic device having a built-in secondary battery, and receives a power supply from an external power source and outputs a charging voltage and a charging current suitable for the electronic device to be charged. A power output unit, a charging connection unit that is connectable to the electronic device via a charging cable, applies the charging voltage to the electronic device and supplies the charging current to the electronic device, and the electronic device. A signal connection unit for receiving at least a value of a secondary battery charging voltage for charging the secondary battery and a value of a voltage drop generated in a circuit through which a secondary battery charging current supplied to the secondary battery flows; and at least the charging An impedance calculation unit that calculates the impedance of the charging cable based on the voltage value, the charging current value, the secondary battery charging voltage value, and the drop voltage value , Comprising a.

For example, the electronic device may divide the charging voltage into at least the secondary battery charging voltage and a voltage drop generated in an electric circuit through which the secondary battery charging current flows, The charging current is divided into at least the secondary battery charging current and a load current supplied to the internal load of the electronic device, and the drop voltage is the shunt resistance provided in the secondary battery charging current and the electric circuit. generated by the product of the value is V _OUT of the charge _voltage, the value I _CHG of the charging _current, the value V _BATT of the battery charge _voltage, the value of the load current is I _L, the shunt when the value of the resistor is _{R 1,} the value _V dROP = _{R 1} × of the voltage drop _(I CHG -I _L), the charger by the following formula (2), the impedance of the charging cable To calculate the _CBL.

  The electronic device of the present invention can be connected to the charger via a secondary battery that can be charged by a charger and a charging cable, and a charging voltage is applied from the charger, and a charging current is supplied from the charger. Between the charging connection section to which the charging current is supplied, the electric path through which the charging current flows, the internal load branched and connected from the electric circuit, the connection point of the electric circuit and the internal load, and the secondary battery, A shunt resistor provided in an electric circuit; and a current detector that detects a secondary battery charging current that flows through the shunt resistor and is supplied to the secondary battery, wherein the charging voltage includes at least the secondary battery. A load that is divided into a charging voltage for the secondary battery to be charged and a voltage drop generated in the shunt resistor, and the charging current is supplied to at least the secondary battery charging current and the internal load. It is diverted to flow Prefecture, further the electronic device comprises a signal connection unit for transmitting a value of at least the value of the secondary battery charging voltage and the battery charging current to the battery charger.

  The electronic device of the present invention can be connected to the charger via a secondary battery that can be charged by a charger and a charging cable, and a charging voltage is applied from the charger, and a charging current is supplied from the charger. Between the charging connection section to which the charging current is supplied, the electric path through which the charging current flows, the internal load branched and connected from the electric circuit, the connection point of the electric circuit and the internal load, and the secondary battery, A shunt resistor provided in an electric circuit; and a current detector that detects a secondary battery charging current that flows through the shunt resistor and is supplied to the secondary battery, wherein the charging voltage includes at least the secondary battery. A load that is divided into a charging voltage for the secondary battery to be charged and a voltage drop generated in the shunt resistor, and the charging current is supplied to at least the secondary battery charging current and the internal load. It is diverted to flow Prefecture, further the electronic device comprises a signal connection unit for transmitting the values of and the voltage drop of at least the secondary battery charging voltage to the battery charger.

  According to the electronic device system, the charger, and the electronic device of the present invention, the impedance of the charging cable that electrically connects the charger and the electronic device, the value of the charging voltage, the value of the charging current, and the charging voltage of the secondary battery And the value of the secondary battery charging current are directly or indirectly calculated on the charger side. Therefore, it is possible to constantly calculate and monitor the impedance of the charging cable on the charger side to find out in the initial state any abnormality of the charging cable that may be disconnected, and to prevent the risk of overcharging and heating of the charging cable in advance. It is possible to avoid it.

The block diagram which shows an example of the electronic device system which concerns on this invention, a charger, and an electronic device. (A) The schematic diagram which shows an example of the electronic device system which concerns on this invention, a charger, and an electronic device, (b) The A section enlarged view of (a).

  Hereinafter, preferred embodiments of an electronic device system, a charger, and an electronic device according to the present invention will be described in detail with reference to FIGS.

  FIG. 1 is a block diagram illustrating an example of an electronic device system, a charger, and an electronic device according to the present invention.

  The electronic device system includes a charger 10 and an electronic device 20. The charger 10 includes a plug that can be electrically connected to an external commercial AC power source, and includes a rectifier 11, a power output unit 12, an impedance calculation unit 13, and an output stop unit 14. Further, the charger 10 acquires a signal sent from the electronic device 20 and a charging connection portion P that is directly or electrically connected to a charging cable K made of USB or the like that can be electrically connected to the electronic device 20. A signal connection S is provided.

The rectifier 11 is an AC / DC converter. The power output unit 12 outputs power suitable for the electronic device 20 to be charged based on the power converted by the rectifier 11. The impedance calculation unit 13 calculates (calculates) the impedance R _CBL of the charging cable K based on the current and voltage values transmitted from the electronic device 20. In addition, the impedance calculation unit 13 obtains the charging voltage value V _OUT and the charging current value I _CHG from the power output unit 12. The output stop unit 14 stops the power supplied from the power output unit 12 based on the calculation result of the impedance calculation unit 13.

  The electronic device 20 includes a terminal unit 30 and a secondary battery 40 that is built in the electronic device 20 and is detachable from the terminal unit 30. The electronic device 20 is a mobile device that is operated by the secondary battery 40, such as a mobile phone such as a smartphone, a mobile terminal such as a tablet, a digital camera, a portable personal computer, and a wireless device. The terminal unit 30 includes a shunt resistor 31, a current detection unit 32, a voltage detection unit 33, an information processing unit 34, a charging connection unit Q, a signal connection unit T, and an electric circuit 35 that electrically connects them, Is provided.

In the terminal unit 30, in addition to the above-described configuration, various circuits that control the terminal unit 30 and the like are mounted, and there is an internal load 36 that is generated by operating during charging of the secondary battery 40. As an example, the internal load 36 is described in a state where it is branched and connected from the electric circuit 35 between the charging connection portion Q and the shunt resistor 31 (see FIG. 1). Also as I _L the value of the load current flowing through the internal load 36.

Shunt resistor 31 is a resistor for detecting a current flowing through the electrical path 35, it is arranged paths on 35 with a value R ₁ of the shunt resistor (implementation). The current detection unit 32 is arranged in parallel with the shunt resistor 31 and detects the value of the secondary battery charging current flowing through the electric circuit 35 (the value obtained by subtracting the load current from the charging current: I _CGH −I _L ). The voltage detection unit 33 detects the value V _BATT of the secondary battery charging voltage supplied to the electric circuit 35. As will be described later, the charging voltage is divided into a secondary battery charging voltage and a voltage drop generated in the electric circuit 35. The information processing unit 34 includes a microprocessor (CPU), etc., values of I _CGH -I _L and the secondary battery charging voltage of the secondary battery charging current sent from the current detector 32 and the voltage detection unit 33 V _BATT is acquired and transmitted to the charger 10 side via the signal connection unit T.

  The secondary battery 40 is, for example, a secondary battery such as a lithium ion secondary battery or a nickel hydride secondary battery. The secondary battery 40 is charged by the power supplied from the external charger 10 or the like, and is supplied to the terminal unit 30 by the charged power. Operate the various configurations provided. Further, the secondary battery 40 includes a PTC (Positive Temperature Coefficient) 41 having a positive resistance temperature characteristic for monitoring the temperature in the secondary battery 40, a battery cell 42, and a protection circuit (protection FET) 43. ing.

  Fig.2 (a) is a schematic diagram which shows an example of the electronic device system which concerns on this invention, a charger, and an electronic device, (b) is the A section enlarged view of (a).

The charging cable K is directly wired from the charger 10, and the end of the charging cable K is electrically connected to the charging connection portion Q of the electronic device 20 by fitting a connector or the like. In the charging cable K, a plurality of copper wires D are bundled (for example, 20 wires) and covered with heat-resistant vinyl or the like. On the user side, since the charging cable is freely bent or the like, a load may be applied to the copper wire D and the wire may be broken (see arrow B). When it is completely disconnected, it may be found as a failure in which the charging current does not flow in the charging cable. However, when breakage of wire, no change was observed in the value V _BATT values I _CGH -I _L and the secondary battery charging voltage of the secondary battery charging current, there is a danger that considered normal charging. If the charging is continued as it is, the charging voltage value _VOUT rises (for example, 4V → 6V, etc.), a load is applied to the charging cable K, and heat may be generated. At that time, the impedance R _CBL of the charging cable K increases. For example, when half of the 20 copper wires D are broken, the impedance R _CBL increases from 0.1Ω (normal value) to 0.2Ω.

The present invention constantly monitors the impedance R _CBL of the charging cable K, finds an abnormality in the charging cable K that may be disconnected in the initial state, and avoids the risk of disconnection. In addition, the disconnection refers to a state in which the copper wire D is only partially connected before being completely disconnected in addition to a state in which the disconnection is about to occur, and the impedance R _CBL of the charging cable K is increased (increased). Say.

The impedance value R _CBL of the charging cable K can be derived from the following formula (1).

In Equation (1), R _CBL is the impedance of the charging cable K, _VOUT is the value of the charging voltage, V _BATT is the value of the secondary battery charging voltage, R ₁ is the value of the shunt resistor 31, and I _CHG is the charging current. , _IL is a load current value. That is, the value _{V DROP (= R 1 × I} CGH -I L) the value of the voltage obtained by subtracting _{(V OUT} of voltage drop by a value _{V BATT} and the shunt resistor 31 of the secondary battery charging voltage from the value _{V OUT} of the charging voltage The impedance R _CBL can be calculated by dividing −V _BATT −R ₁ × (I _CGH −I _L )) by the charging current value I _CGH . Each value will be described in detail below with reference to FIG.

When the charger 10 and the electronic device 20 are electrically connected via the charging cable K, the charging voltage is supplied from the power output unit 12 to the electronic device 20 via the charging connection portion P, the charging cable K, and the charging connection portion Q. Is applied and a charging current is supplied. The charging voltage value _VOUT and the charging current value I _CHG supplied from the power output unit 12 to the electronic device 20 are transmitted from the power output unit 12 to the impedance calculation unit 13. The impedance calculation unit 13 stores a charging voltage value _VOUT and a charging current value I _CHG together with a normal value of the impedance R _CBL of the charging cable K stored in advance.

Some of the charging current is shunted as the load current required internal load 36 (the value I _L), the value of the current obtained by subtracting the load current becomes a value I _CGH -I _L of the rechargeable battery charging current. The charging voltage is divided into a secondary battery charging voltage and a voltage drop generated by the shunt resistor 31 on the electric circuit 35. The value _{V DROP} of the voltage drop is calculated by the value _I CGH -I _L and the product _{R 1} value of the shunt resistor 31 of the secondary battery charging current. That is, V _DROP = R ₁ × (I _CGH −I _L ).

The current detector 32 detects the secondary battery charging current flowing between the shunt resistors 31, and the voltage detector 33 detects the secondary battery charging voltage that has passed through the shunt resistor 31. Then, the value V _BATT of the detected secondary battery charging voltage by the current detection unit 32 the value of the detected secondary battery charge current I _CGH -I _L and the voltage detection unit 33 is transmitted to the information processing unit 34 . The information processing unit 34 transmits the acquired value to the impedance calculation unit 13 of the charger 10 via the signal connection unit T, the charging cable K, and the signal connection unit S. The value R ₁ of the shunt resistor 31 may be stored in the information processing unit 34 and transmitted to the impedance calculation unit 13 and stored in the impedance calculation unit 13 when the charger 10 and the electronic device 20 are connected. The impedance calculation unit 13 may store the information in advance.

The impedance calculation unit 13 includes the acquired charging voltage value V _OUT , charging current value I _CHG , secondary battery charging current value I _CGH −I _L , secondary battery charging voltage value V _BATT, and shunt resistance 31. calculating the impedance _{R CBL} of charging cable K on the basis of the value _{R 1.} See equation (1) above. When the calculated impedance R _CBL is larger than a predetermined value, a command (command) is issued to the output stop unit 14, and the output stop unit 14 applies the charging voltage from the power output unit 12 and the charging current based on the command. Stop supplying.

Although it has been described that the impedance calculation unit 13 calculates all, the value that the information processing unit 34 can acquire on the electronic device 20 side may be calculated in advance. In other words, the value V _DROP (= R ₁ × (I _CGH −I _L )) of the drop voltage is calculated by the information processing unit 34 and transmitted to the impedance calculation unit 13. Then, the impedance calculator 13 calculates the impedance R _CBL of the charging cable K based on the following equation (2).

In Equation (2), R _CBL is the impedance of the charging cable K, _VOUT is the charging voltage value, V _BATT is the secondary battery charging voltage value, V _DROP is the drop voltage value, and I _CHG is the charging current value. Value.

The impedance calculation unit 13 of the charger 10 constantly or intermittently calculates the impedance R _CBL of the charging cable K based on the acquired various values. When the impedance calculation unit 13 determines that the calculated value of the impedance R _CBL is greater than a predetermined value, the charging voltage from the power output unit 12 of the charger 10 to the electronic device 20 via the output stop unit 14 is determined. The application and supply of charging current are stopped. By this operation, an abnormality such as disconnection of the charging cable K can be found in the initial state, and the danger of overcharging and heat generation of the charging cable K can be avoided in advance.

In the embodiment of FIG. 1, it has been described above that the current detection unit 32 is arranged in parallel with the shunt resistor 31. However, instead of the current detection unit 32, a voltage detection unit 33 is arranged to directly detect a voltage drop. It may be a configuration. Dividing the value _{V DROP} of the detected voltage drop in the value _{R 1} of the shunt resistor 31, the secondary battery charging current value _{I CGH -I L (= V DROP} / R 1) can be calculated.

  In addition, this invention is not limited to embodiment mentioned above, A deformation | transformation, improvement, etc. are possible suitably. In addition, the material, shape, dimension, numerical value, form, number, arrangement location, and the like of each component in the above-described embodiment are arbitrary and are not limited as long as the present invention can be achieved.

  An electronic device system, a charger, and an electronic device according to the present invention include a charging cable when charging a secondary battery such as a mobile phone such as a smartphone, a mobile terminal such as a tablet, a digital camera, a portable personal computer, or a radio. It can be applied to the purpose of preventing abnormalities in advance.

DESCRIPTION OF SYMBOLS 10: Charger 11: Rectifier 12: Power output part 13: Impedance calculation part 14: Output stop part 20: Electronic device 30: Terminal part 31: Shunt resistance 32: Current detection part 33: Voltage detection part 34: Information processing part 35 : path 36: the internal load 40: secondary battery K: charging cable P, Q: charge connection portions S, T: signal connection I _CGH: value of the charging current I _L: the value of the load current I _CGH -I _L: two Secondary battery charging current value R ₁ : Shunt resistance value R _CBL : Charging cable impedance V _OUT : Charging voltage value V _BATT : Secondary battery charging voltage value

Claims (17)

An electronic device system including an electronic device having a built-in secondary battery, a charger, and a charging cable for connecting the electronic device and the charger,
The charger applies a charging voltage to the electronic device via the charging cable, and supplies a charging current to the electronic device.
The electronic device divides the charging voltage into at least a secondary battery charging voltage for charging the secondary battery and a voltage drop generated in a circuit through which a secondary battery charging current supplied to the secondary battery flows, The charging current is divided into at least the secondary battery charging current and a load current supplied to the internal load of the electronic device,
The electronic device transmits at least the value of the secondary battery charging voltage and the value of the secondary battery charging current to the charger,
The charger calculates an impedance of the charging cable based on at least the value of the charging voltage, the value of the charging current, the value of the secondary battery charging voltage, and the value of the secondary battery charging current. , Electronic equipment system. The electronic device system according to claim 1,
The internal load is branched and connected from the electric circuit, and the secondary battery charging current is obtained by subtracting the load current from the charging current,
The drop voltage is generated by a product of the secondary battery charging current and a shunt resistor provided in the electric circuit,
The electronic device system, wherein the charger stores a value of the shunt resistor. The electronic device system according to claim 2,
The electronic device system further comprising: a current detection unit that detects the secondary battery charging current using the shunt resistor. The electronic device system according to claim 2 or 3,
The value of the charging voltage _{V OUT,} the value of the charging current _{I CHG,} value _{V BATT} of the battery charge voltage, the value of the load current is _{I L,} the value of the shunt resistor is _{R 1} The charger calculates the impedance R _{CBL of the} charging cable according to the following equation.

The electronic device system according to any one of claims 1 to 4,
When the impedance of the charging cable is greater than a predetermined value, the charger stops applying the charging voltage and supplying the charging current. An electronic device system including an electronic device having a built-in secondary battery, a charger, and a charging cable for connecting the electronic device and the charger,
The charger applies a charging voltage to the electronic device via the charging cable, and supplies a charging current to the electronic device.
The electronic device divides the charging voltage into at least a secondary battery charging voltage for charging the secondary battery and a voltage drop generated in a circuit through which a secondary battery charging current supplied to the secondary battery flows, The charging current is divided into at least the secondary battery charging current and a load current supplied to the internal load of the electronic device,
The electronic device transmits at least the value of the secondary battery charging voltage and the value of the drop voltage to the charger;
The charger calculates an impedance of the charging cable based on at least the value of the charging voltage, the value of the charging current, the value of the secondary battery charging voltage, and the value of the voltage drop. system. The electronic device system according to claim 6,
The internal load is branched and connected from the electric circuit, and the secondary battery charging current is obtained by subtracting the load current from the charging current,
The voltage drop is generated by a product of the secondary battery charging current and a shunt resistor provided in the electric circuit. The electronic device system according to claim 7,
The electronic device system further comprising: a current detection unit that detects the secondary battery charging current using the shunt resistor. The electronic device system according to claim 7 or 8,
The value of the charging voltage _{V OUT,} the value of the charging current _{I CHG,} value _{V BATT} of the battery charge voltage, the value of the load current is _{I L,} the value of the shunt resistor is _{R 1} When the drop voltage value V _DROP = R ₁ × (I _CHG −I _L ), the charger calculates the impedance R _{CBL of the} charging cable according to the following equation.

The electronic device system according to any one of claims 6 to 9,
When the impedance of the charging cable is greater than a predetermined value, the charger stops applying the charging voltage and supplying the charging current. A charger capable of charging an electronic device with a built-in secondary battery,
A power output unit that receives power supply from an external power source and outputs a charging voltage and a charging current suitable for the electronic device to be charged;
A charging connection unit that is connectable to the electronic device via a charging cable, and that applies the charging voltage to the electronic device and supplies the charging current to the electronic device;
A signal connection unit that receives a value of a secondary battery charging voltage for charging at least the secondary battery and a value of a secondary battery charging current supplied to the secondary battery from the electronic device;
Based on at least the value of the charging voltage, the value of the charging current, the value of the secondary battery charging voltage, and the value of the secondary battery charging current, an impedance calculator that calculates the impedance of the charging cable;
With a charger. The charger according to claim 11, wherein
The electronic device divides the charging voltage into at least the secondary battery charging voltage and a voltage drop generated in an electric circuit through which the secondary battery charging current flows, and the charging current is at least the secondary battery charging current. And the load current supplied to the internal load of the electronic device,
The drop voltage is generated by a product of the secondary battery charging current and a shunt resistor provided in the electric circuit,
The charger stores the value of the shunt resistor, the charging voltage value is V _OUT , the charging current value is I _CHG , the secondary battery charging voltage value is V _BATT , and the load current is is I _L, when the value of the shunt resistor is R _1, the impedance calculation unit by the following formula to calculate the impedance R _CBL of the charging cable, charger.

The charger according to claim 11 or 12,
When the impedance of the charging cable is greater than a predetermined value, the power output unit stops applying the charging voltage and supplying the charging current. A charger capable of charging an electronic device with a built-in secondary battery,
A power output unit that receives power supply from an external power source and outputs a charging voltage and a charging current suitable for the electronic device to be charged;
A charging connection unit that is connectable to the electronic device via a charging cable, and that applies the charging voltage to the electronic device and supplies the charging current to the electronic device;
A signal connection unit for receiving, from the electronic device, at least a value of a secondary battery charging voltage for charging the secondary battery and a value of a voltage drop generated in an electric circuit through which a secondary battery charging current supplied to the secondary battery flows; ,
Based on at least the value of the charging voltage, the value of the charging current, the value of the secondary battery charging voltage, and the value of the voltage drop, an impedance calculator that calculates the impedance of the charging cable;
With a charger. The charger according to claim 14, wherein
The electronic device divides the charging voltage into at least the secondary battery charging voltage and a voltage drop generated in an electric circuit through which the secondary battery charging current flows, and the charging current is at least the secondary battery charging current. And the load current supplied to the internal load of the electronic device,
The drop voltage is generated by a product of the secondary battery charging current and a shunt resistor provided in the electric circuit,
The value of the charging voltage _{V OUT,} the value of the charging current _{I CHG,} value _{V BATT} of the battery charge voltage, the value of the load current is _{I L,} the value of the shunt resistor is _{R 1} when a value _V dROP = _{R 1} × of the voltage drop _(I CHG -I _L), the charger according to the following equation to calculate the impedance _{R CBL} of the charging cable, charger.

A secondary battery that can be charged by a charger;
A charging connection that is connectable to the charger via a charging cable, is applied with a charging voltage from the charger, and is supplied with a charging current from the charger;
An electric circuit through which the charging current flows;
An internal load branched and connected from the electrical circuit;
Between the connection point of the electric circuit and the internal load and the secondary battery, a shunt resistor provided in the electric circuit,
A current detector that flows through the shunt resistor and detects a secondary battery charging current supplied to the secondary battery, and an electronic device comprising:
The charging voltage is divided into at least a secondary battery charging voltage for charging the secondary battery and a voltage drop generated in the shunt resistor, and the charging current is at least the secondary battery charging current and the internal voltage. Is shunted to the load current supplied to the load,
The electronic device further includes a signal connection unit that transmits at least the value of the secondary battery charging voltage and the value of the secondary battery charging current to the charger. A secondary battery that can be charged by a charger;
A charging connection that is connectable to the charger via a charging cable, is applied with a charging voltage from the charger, and is supplied with a charging current from the charger;
An electric circuit through which the charging current flows;
An internal load branched and connected from the electrical circuit;
Between the connection point of the electric circuit and the internal load and the secondary battery, a shunt resistor provided in the electric circuit,
A current detector that flows through the shunt resistor and detects a secondary battery charging current supplied to the secondary battery, and an electronic device comprising:
The charging voltage is divided into at least a secondary battery charging voltage for charging the secondary battery and a voltage drop generated in the shunt resistor, and the charging current is at least the secondary battery charging current and the internal voltage. Is shunted to the load current supplied to the load,
The electronic device further includes a signal connection unit that transmits at least the value of the secondary battery charging voltage and the value of the drop voltage to the charger.

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