JP2015012710A - Electronic apparatus and electronic apparatus system - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an electronic apparatus that has a fail-safe function capable of directly or indirectly detecting abnormality of a charging cable on an electric apparatus side to improve the reliability of charging to a secondary battery, and to provide an electronic apparatus system.SOLUTION: An electronic apparatus system is composed of a charger 10 and an electronic apparatus 20. The charger 10 includes a power output unit 12, an output stop unit 13, and a charging cable K. The electronic apparatus 20 is composed of a terminal part 30 and a secondary battery 40. The terminal part 30 includes a cut-off circuit 31, a shunt resistor 32, a current detection unit 33, a voltage detection unit 34, an impedance calculation unit 35, a charging-cable status determination unit 36, and an electrical path 37, and has an internal load 38. The impedance calculation unit 35 calculates the impedance Rof the charging cable K on the basis of the value of a charging voltage V, the value of a charging current I, the value of a secondary-battery charging current I-I, and the value of a secondary-battery charging voltage V.

Description

  The present invention relates to an electronic device and an electronic device system 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 electronic device side, and safety of charging a secondary battery. It is an object of the present invention to provide an electronic device and an electronic device system with improved performance.

  The electronic device of the present invention can be connected to the charger via a rechargeable battery that can be charged by a charger and a charging cable, and a charging voltage is applied and a charging current is supplied from the charger. A charging connection unit capable of receiving the value of the charging voltage and the value of the charging current from the charger, at least the value of the charging voltage, the value of the charging current, and a secondary battery charging for charging the secondary battery; An impedance calculator that calculates an impedance of the charging cable based on a voltage value and a secondary battery charging current value supplied to the secondary battery.

  Examples of the electronic apparatus according to the present invention include, for example, an electric circuit through which the charging current flows, an internal load that is branched from the electric circuit, and a connection point between the electric circuit and the internal load and the secondary battery. In addition, a shunt resistor provided in the 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 is at least the The voltage is divided into a secondary battery charging voltage and a voltage drop generated in the shunt resistor, and the charging current is divided into at least the secondary battery charging current and a load current supplied to the internal load.

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 in the value of the shunt resistor when R _1, the impedance calculation unit by the following formula to calculate the impedance R _CBL of the charging cable.

  Examples of the electronic apparatus according to the present invention include, for example, an electric circuit through which the charging current flows, an internal load that is branched from the electric circuit, and a connection point between the electric circuit and the internal load and the secondary battery. In addition, a shunt resistor provided in the electric circuit, and a voltage detection unit that detects a voltage drop generated in the shunt resistor, the charge voltage is at least the secondary battery charge voltage and the voltage drop. While being divided, the charging current is divided into at least the secondary battery charging current and the load current supplied to the internal load.

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 drop voltage value is V _DROP. In this case, the impedance calculation unit calculates the impedance R _{CBL of the} charging cable according to the following equation.

  For example, the electronic device according to the present invention further includes a communication connection unit that transmits an impedance value of the charging cable to the charger.

  As a variety of electronic devices of the present invention, for example, when the impedance value of the charging cable is larger than a predetermined value, a charging cable state determining unit that determines that the impedance is abnormal, and the charging cable state determining unit include And a communication connection unit that transmits an impedance abnormality signal to the charger when it is determined that the impedance is abnormal.

  For example, the electronic device according to the present invention further includes a cut-off circuit that cuts off the application of the charging voltage and the supply of the charging current from the charger when the abnormal impedance signal is transmitted.

  As a variety of electronic devices of the present invention, for example, when the impedance value of the charging cable is larger than a predetermined value, a charging cable state determining unit that determines that the impedance is abnormal, and the charging cable state determining unit include And a communication connection unit for transmitting to the charger a stop command command for stopping the application of the impedance abnormality signal, the charging voltage, and the supply of the charging current when it is determined that the impedance is abnormal.

  For example, the electronic apparatus according to the present invention further includes a cutoff circuit that cuts off the application of the charging voltage and the supply of the charging current from the charger when the impedance abnormality signal and the stop command are transmitted.

  An electronic device system according to the present invention includes an electronic device and a charger.

  According to the electronic device and the electronic device system 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 value of the secondary battery charging voltage Based on the value of the secondary battery charging current, it is directly or indirectly calculated on the electronic device side. Therefore, it is possible to constantly calculate and monitor the impedance of the charging cable on the electronic device side to find out in the initial state any abnormality in the charging cable that may cause disconnection, and to prevent the risk of overcharging and heating of the charging cable in advance. It is possible to avoid it.

1 is a block diagram showing an example of a first embodiment of an electronic device and an electronic device system according to the present invention. (A) The schematic diagram which shows an example of the electronic device and electronic device system which concern on this invention, (b) The A section enlarged view of (a). The block diagram which shows an example of 2nd Embodiment of the electronic device and electronic device system which concern on this invention.

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

  FIG. 1 is a block diagram showing an example of a first embodiment of an electronic device and an electronic device system 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, and an output stop unit 13. 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 communication 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 output stop unit 13 stops the power supplied from the power output unit 12 based on the signal from the electronic device 20.

  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 cutoff circuit 31, a shunt resistor 32, a current detection unit 33, a voltage detection unit 34, an impedance calculation unit 35, a charging cable state determination unit 36, a charging connection unit Q, and a communication connection unit. T and the electric circuit 37 which electrically connects these are 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 38 that is generated by operating during charging of the secondary battery 40. As an example, the internal load 38 is described in a state where it is branched and connected from the electric circuit 37 between the cutoff circuit 31 and the shunt resistor 32 (see FIG. 1). Also as I _L the value of the load current flowing through the internal load 38.

The interruption circuit 31 receives the signal from the charging cable state determination unit 36 and interrupts the application of the charging voltage and the supply of the charging current from the charger 10. Shunt resistor 32 is a resistor for detecting a current flowing through the path 37, are arranged in tracks on the 35 has a value R ₁ of the shunt resistor (implementation). The current detection unit 33 is arranged in parallel with the shunt resistor 32 and detects the value of the secondary battery charging current flowing through the electric circuit 37 (the value obtained by subtracting the load current from the charging current: I _CGH −I _L ). The voltage detection unit 34 detects a value V _BATT of the secondary battery charging voltage supplied to the electric circuit 37. 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 37.

Impedance computing unit 35 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 33 and the voltage detection unit 34 V _{In addition} to obtaining _BATT , a charge voltage value _VOUT and a charge current value _ICHG transmitted from the power output unit 12 of the charger 10 are obtained. Then, the impedance R _CBL of the charging cable K is calculated (calculated) based on these acquired values. The charging cable state determination unit 36 determines whether the impedance of the charging cable K is abnormal based on the calculation result sent from the impedance calculation unit 35, and determines that the impedance is abnormal, the impedance abnormality signal And generate a stop command.

  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.

  2A is a schematic diagram illustrating an example of an electronic device and an electronic device system according to the present invention, and FIG. 2B is an enlarged view of a portion A in FIG.

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 the state in which the disconnection is about to occur, and is compared with a predetermined value (normal value) of the charging cable K. The impedance R _CBL is increased (increased).

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 32, and I _CHG is the charging current. , _IL is a load current value.

That is, the value _{V BATT} of battery charging voltage from the value _{V OUT} of the charge voltage, the value _I CGH -I _L value _{R 1} and the secondary battery charging current of the shunt resistor 32 product _{(R 1} × _I CGH -I _L ) and the value of the voltage minus (V _OUT −V _BATT −R ₁ × (I _CGH −I _L )). Then, the impedance R _CBL can be calculated by dividing the voltage value (V _OUT −V _BATT −R ₁ × (I _CGH −I _L )) by the charging current value I _CGH . The acquisition of each value, the calculation based thereon, and the abnormality determination based on the calculation result 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. Then, the charging voltage value V _OUT 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 communication connection unit S, and the charging cable K and the electronic device 20 It is transmitted to the impedance calculation unit 35 via the communication connection unit T. Impedance computing section 35, together with the value R ₁ of the shunt resistor 32 stored in advance, stores the value V _OUT of the received charge voltage value I _CHG of the charging current.

Some of the charging current is diverted as required load current to the internal load 38 (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. Further, the charging voltage is divided into a secondary battery charging voltage and a voltage drop generated by the shunt resistor 32 on the electric circuit 37.

The current detector 33 detects the secondary battery charging current flowing between the shunt resistors 32, and the voltage detector 34 detects the secondary battery charging voltage that has passed through the shunt resistor 32. Then, the value V _BATT values I _CGH -I _L and detected by the voltage detection unit 34 the secondary battery charging voltage of the detected secondary battery charging current by the current detecting section 33 is transmitted to the impedance calculation unit 35 .

The impedance calculation unit 35 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 resistor 32. calculating the impedance _{R CBL} of charging cable K on the basis of the value _{R 1.} See equation (1) above. The calculated impedance R _CBL is transmitted to the charging cable state determination unit 36.

The charging cable state determination unit 36 also stores a predetermined value of the impedance R _CBL of the charging cable K transmitted from the charger 10. When the calculated impedance R _CBL is larger than a predetermined value, that is, when it is determined that the impedance of the charging cable K is abnormal, an impedance abnormality signal and a stop command are generated. Then, the charging cable state determination unit 36 transmits the impedance abnormality signal and the stop command command to the communication connection unit T of the terminal unit 30. Next, the communication connection unit T of the terminal unit 30 issues a stop command command for stopping the application of the impedance abnormality signal and the charging voltage and the supply of the charging current via the charging cable K and the communication connection unit S of the charger 10. It transmits to the output stop part 13 of the charger 10. Then, the output stop unit 13 that has received the impedance abnormality signal and the stop command command stops the application of the charging voltage and the supply of the charging current from the power output unit 12 based on the stop command command.

The impedance calculation unit 35 of the terminal unit 30 always calculates the impedance R _CBL of the charging cable K based on the acquired various values, and transmits the result to the charging cable state determination unit 36. When the charging cable state determination unit 36 determines that the calculated value of the impedance R _CBL is greater than a predetermined value, charging from the power output unit 12 of the charger 10 to the electronic device 20 via the output stop unit 13 is performed. The application of voltage and the 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.

  On the other hand, the charging cable state determination unit 36 transmits the impedance abnormality signal and the stop command command to the cutoff circuit 31 at the time of transmission to the communication connection unit T. The interruption circuit 31 interrupts the application of the charging voltage and the supply of the charging current from the charger 10 based on the stop command. By providing the interruption circuit 31, even when an abnormality such as a failure occurs on the charger 10 side and the application of the charging voltage and the supply of the charging current to the electronic device 20 are continued, the secondary battery 40 can be charged. Can be blocked. Accordingly, since the electronic device 20 can independently cut off the application of the charging voltage and the supply of the charging current from the charger 10 side, it is possible to prevent overcharging to the electronic device 20 and the like, and safety during charging. May improve.

FIG. 3 is a block diagram showing an example of the second embodiment of the electronic device and the electronic device system according to the present invention. The second embodiment is different from the first embodiment in that a voltage detection unit 34 is mounted in parallel with the shunt resistor 32. The voltage detection unit 34 acquires, for example, a value V _DROP of a drop voltage generated by the shunt resistor 32 and a value V _BATT of the secondary battery charging voltage by time-sharing control of a well-known changeover switch (not shown). The specific configuration is not particularly limited. Note that the description of the same operation and the like as in the first embodiment is omitted.

The voltage detection unit 34 detects the value V _{DROP of the} drop voltage generated by the shunt resistor 32 and the value V _BATT of the secondary battery charging voltage. When the charger 10 and the electronic device 20 are electrically connected via the charging cable K, the impedance calculation unit 35 receives from the power output unit 12 together with the shunt resistor 32 and the value R ₁ stored in advance. The charging voltage value V _OUT and the charging current value I _CHG are stored. Then, the impedance calculation unit 35 acquires the value V _{DROP of the} drop voltage generated by the shunt resistor 32 and the value V _BATT of the secondary battery charging voltage from the voltage detection unit 34.

Based on the charging voltage value V _OUT , the secondary battery charging voltage value V _BATT , the drop voltage value V _DROP, and the charging current value I _CHG , the impedance calculator 35 calculates the charging cable K using the following equation (2). The impedance value R _CBL is calculated.

That is, the value of the voltage obtained by subtracting the value _{V DROP} value _{V BATT} and voltage drop of the secondary battery charging voltage from the value _{V OUT} of the charging voltage _{(V OUT -V BATT -V DROP)} , the charging current value _{I CGH} The impedance R _CBL can be calculated by dividing by.

When the calculated impedance R _CBL is greater than a predetermined value, the charging cable state determination unit 36 generates an impedance abnormality signal and a stop command command, and passes through the communication connection unit T, the charging cable K, and the communication connection unit S. To the charger 10. Then, the output stop unit 13 that has received the impedance abnormality signal and the stop command command stops the application of the charging voltage and the supply of the charging current from the power output unit 12 based on the stop command command. At the same time, the interruption circuit 31 is interrupted, and the application of the charging voltage from the charger 10 to the electronic device 20 and the supply of the charging current are stopped as in the first embodiment.

In the first embodiment, the formula (1) is described above, and in the second embodiment, the formula (2) is described above. However, the formula (1) and the formula (2) may be used in both the first embodiment and the second embodiment. Is available. Expressions (1) and (2) are examples of calculating the impedance R _CBL of the charging cable K and are not particularly limited.

In the first embodiment, since the value _I CGH -I _L of the rechargeable battery charging current is able to detect, by calculating the value _{V DROP} of the voltage drop from the value _I CGH -I _L of the rechargeable battery charging current, Equation (2) can be used. That is, the value _{V DROP} of the voltage drop of the formula (2) can be calculated as the product of the values of _I CGH -I _L and the shunt resistor 32 of the secondary battery charging current _{(V DROP = R 1 × (} I CGH -I _L )). In the second embodiment, since the value _{V DROP} of the voltage drop is able to detect, by calculating the value _I CGH -I _L of the rechargeable battery charging current from the value _{V DROP} of the voltage drop, the formula (1) Can be used. That is, the value _I CGH -I _L of the rechargeable battery charging current of the formula (1) the value _{V DROP} of the voltage drop can be calculated by dividing the value _{R 1} of the shunt resistor _{32 ((I CGH -I L)} = V _DROP / _R 1).

  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.

  When an electronic device and an electronic device system according to the present invention charge 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 wireless device, an abnormality of the charging cable is detected. It can be applied to prevent use.

DESCRIPTION OF SYMBOLS 10: Charger 11: Rectifier 12: Power output part 13: Output stop part 20: Electronic equipment 30: Terminal part 31: Shut-off circuit 32: Shunt resistance 33: Current detection part 34: Voltage detection part 35: Impedance calculation part 36: charging cable state determination unit 37: path 38: the internal load 40: secondary battery K: charging cable P, Q: charge connection portions S, T: the communication connection section I _CGH: value of the charging current I _L: load current value I _CGH -I _L: battery value of the charging current R _1: the value of the shunt resistor R _CBL: impedance V _OUT of the charging cable: the value V _BATT of the charging voltage: the secondary battery charging voltage value

The electronic device of the present invention can be connected to the charger via a rechargeable battery that can be charged by a charger and a charging cable, and a charging voltage is applied and a charging current is supplied from the charger. A charging connection unit capable of receiving the value of the charging voltage and the value of the charging current from the charger, at least the value of the charging voltage, the value of the charging current, and a secondary battery charging for charging the secondary battery; An electronic apparatus comprising: an impedance calculation unit that calculates an impedance of the charging cable based on a voltage value and a value of a secondary battery charging current supplied to the secondary battery , wherein the charging current flows A shunt resistor provided in the electric circuit between the electric circuit, an internal load branched from the electric circuit and connected, a connection point of the electric circuit and the internal load, and the secondary battery, and the shunt A current detection unit that detects a secondary battery charging current supplied to the secondary battery and that is supplied to the secondary battery, wherein the charging voltage is a voltage drop generated at least in the secondary battery charging voltage and the shunt resistor. And the charging current is divided into at least the secondary battery charging current and the load current supplied to the internal load .

The electronic device of the present invention can be connected to the charger via a rechargeable battery that can be charged by a charger and a charging cable, and a charging voltage is applied and a charging current is supplied from the charger. A charging connection unit capable of receiving the value of the charging voltage and the value of the charging current from the charger, at least the value of the charging voltage, the value of the charging current, and a secondary battery charging for charging the secondary battery; An electronic apparatus comprising: an impedance calculation unit that calculates an impedance of the charging cable based on a voltage value and a value of a secondary battery charging current supplied to the secondary battery, wherein the charging current flows A shunt resistor provided in the electric circuit between the electric circuit, an internal load branched from the electric circuit and connected, a connection point of the electric circuit and the internal load, and the secondary battery, and the shunt A voltage detector for detecting a voltage drop generated in the resistor, wherein the charging voltage is divided into at least the secondary battery charging voltage and the voltage drop, and the charging current is at least the second voltage. The current is divided into a secondary battery charging current and a load current supplied to the internal load.

Claims (11)

A secondary battery that can be charged by a charger;
It can be connected to the charger via a charging cable, a charging voltage is applied from the charger and a charging current is supplied, and further, the charging voltage value and the charging current value can be received from the charger. A charging connection,
Based on at least the value of the charging voltage, the value of the charging current, the value of the secondary battery charging voltage for charging the secondary battery, and the value of the secondary battery charging current supplied to the secondary battery, An impedance calculator for calculating the impedance of the charging cable;
Electronic equipment comprising. The electronic device according to claim 1,
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 detects a secondary battery charging current that flows through the shunt resistor and is supplied to the secondary battery;
The charging voltage is divided into at least the secondary battery charging voltage 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. Electronic devices that are shunted into current. The electronic device according to claim 2,
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} In this case, the impedance calculation unit calculates the impedance R _{CBL of the} charging cable according to the following equation.

The electronic device according to claim 1,
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 voltage detection unit that detects a voltage drop generated in the shunt resistor, the charge voltage is divided into at least the secondary battery charge voltage and the voltage drop, and the charge current is at least An electronic device that is shunted into the secondary battery charging current and a load current supplied to the internal load. 5. The electronic device according to claim 4, wherein 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 drop voltage value is V _DROP. In this case, the impedance calculation unit calculates the impedance R _{CBL of the} charging cable according to the following equation.

The electronic device according to any one of claims 1 to 5,
An electronic apparatus further comprising a communication connection unit that transmits an impedance value of the charging cable to the charger. The electronic device according to any one of claims 1 to 5,
If the value of the impedance of the charging cable is greater than a predetermined value, a charging cable state determination unit that determines that the impedance is abnormal,
An electronic apparatus, further comprising: a communication connection unit that transmits an impedance abnormality signal to the charger when the charging cable state determination unit determines that the impedance is abnormal. The electronic device according to claim 7,
An electronic apparatus, further comprising: a cutoff circuit that cuts off the application of the charging voltage from the charger and the supply of the charging current when the impedance abnormality signal is transmitted. The electronic device according to any one of claims 1 to 5,
If the value of the impedance of the charging cable is greater than a predetermined value, a charging cable state determination unit that determines that the impedance is abnormal,
When the charging cable state determination unit determines that the impedance is abnormal, the communication connection unit transmits an impedance abnormality signal, a stop command command for stopping the application of the charging voltage and the supply of the charging current to the charger. And an electronic device. The electronic device according to claim 9,
An electronic apparatus, further comprising: a cutoff circuit that cuts off the application of the charging voltage and the supply of the charging current from the charger when transmitting the impedance abnormality signal and the stop command.   The electronic device system containing the electronic device of any one of Claim 1 to 10, and a charger.

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