JP4739163B2 - Charge control device and charge control method - Google Patents

Description

  The present invention relates to a charge control device and a charge control method for controlling a charging current from an external power source to a secondary battery.

  As shown in FIG. 5, the conventional charge control device includes a second resistor 102 for detecting a charging current to the battery 11 and a field effect transistor (hereinafter simply referred to as a current effect transistor capable of limiting the current flowing through the second resistor 102). FET, 105), a charging current detecting means 103 for measuring a voltage drop in the second resistor 102 and detecting a current flowing through the second resistor 102, a battery voltage detecting means 109 for monitoring the voltage of the battery 11, Charge control means 107 for controlling the FET 105 is provided.

The charging control means 107 executes constant current charging control that keeps the output current of the external power source constant until the battery voltage reaches a predetermined voltage. When the battery voltage reaches the predetermined voltage, the battery voltage is kept constant. The control proceeds to charging current limit charging control that limits the charging current of the battery to a predetermined upper limit current value or less while maintaining the voltage of the battery 11 when the charging current of the battery falls below the predetermined lower limit current value. The process shifts to constant voltage charge control that maintains constant, and then shifts to constant voltage charge control to suppress heat loss in the FET 105 (see, for example, Patent Document 1).
JP 2004-222446 A

  However, in the conventional charging control device, it is determined that the charging is terminated when the charging current of the battery becomes equal to or lower than a predetermined current value. There is a problem that the charging current becomes equal to or less than a predetermined value and it is determined that charging is terminated.

  The present invention has been made to solve the conventional problem, and even when a device is used during charging, accurately controlling charging voltage and detecting charging current while limiting heat generation during charging. An object of the present invention is to provide a charge control device and a charge control method capable of performing the above.

  The charge control device of the present invention is a charge control device that is interposed between an external power source and a battery and controls a charging current of the battery, and includes a battery voltage detection unit that detects the voltage of the battery, and the external power source. Charging current detecting means for detecting a current from the battery and a charging current of the battery, and a constant current charging control for suppressing the current from the external power source to a first current value until the voltage of the battery reaches a predetermined voltage. When the voltage of the battery reaches a predetermined voltage, charging current limit charging control is performed to limit the current from the external power source to a second current value smaller than the first current value while keeping the battery voltage constant. Charging control means for transferring, and the charging current detection means charges the battery when the charging current limit charging control is released intermittently. And it has a structure for detecting the flow.

  With this configuration, it is possible to accurately control the charging voltage and detect the charging current while restricting heat generation during charging.

  The charging control device according to the present invention further includes a charging current determination unit that determines whether or not a charging current of the battery has become equal to or smaller than a third current value that is smaller than the second current value, and the charging control unit includes: When the charging current becomes equal to or less than the third current value, the configuration shifts to constant voltage charging control for keeping the voltage of the battery constant.

  With this configuration, it is possible to prevent the transition from the charging current limit charging control to the constant voltage charging control in a state where the charging rate of the battery is low.

  In the charging control apparatus according to the present invention, the charging current determining unit determines whether or not the charging current of the battery is equal to or lower than a fourth current value smaller than the third current value, and the charging control unit includes the battery When the charging current becomes equal to or less than the fourth current value, the current from the external power supply is stopped and the constant voltage charging control is completed.

  With this configuration, it is possible to prevent the transition from the charging current limit charging control to the constant voltage charging control in a state where the charging rate of the battery is low.

  The charge control device of the present invention includes a load current detection means for detecting a load current to the load from the current from the external power source and the charging current of the battery, and whether or not the load current is greater than a fifth current value. Load current determining means for determining, and when the load current is greater than or equal to the fifth current value, the load current determining means provides the charge control means until the charge current of the battery becomes less than or equal to the third current value. The charging current limiting charging control is continuously executed.

  With this configuration, it is possible to prevent the transition from the charging current limit charging control to the constant voltage charging control in a state where the charging rate of the battery is low.

  The charge control device of the present invention includes a load current detection means for detecting a load current to the load from the current from the external power source and the charging current of the battery, and whether or not the load current is greater than a fifth current value. A load current determining means for determining; and a time measuring means for measuring an elapsed time since the transition to the charging current charge control, wherein the load current determining means is configured such that when the load current is equal to or greater than the fifth current value, The charging control unit is configured to continuously execute the charging current limit charging control until the time measuring unit passes a preset time.

  With this configuration, it is possible to prevent the transition from the charging current limit charging control to the constant voltage charging control in a state where the charging rate of the battery is low.

  The charge control device of the present invention includes a first resistor having one end connected to the battery, a second resistor having one end connected to the other end of the first resistor, and a first terminal connected to the external power source. A second terminal connected to the second resistor; and a current limiting element that outputs a current from the external power source to the second resistor, and the charging current detecting means includes the first resistor and the second resistor. It has a configuration in which a current from an external power source is detected and a charging current of the battery is detected by the second resistor.

  With this configuration, it is possible to prevent the transition from the charging current limit charging control to the constant voltage charging control in a state where the charging rate of the battery is low.

  The charge control device of the present invention includes a third resistor having one end connected to the other end of the first resistor and the other end connected to a load, and a load current for detecting a load current to the load by the third resistor. Detecting means; and load current determining means for determining whether or not the load current is greater than a fifth current value, wherein the load current determining means is configured such that when the load current is greater than or equal to the fifth current value, the battery Until the charging current becomes equal to or lower than the third current value, the charging control means continuously executes the charging current limiting charging control.

  With this configuration, it is possible to prevent the transition from the charging current limit charging control to the constant voltage charging control in a state where the charging rate of the battery is low.

  The charge control device of the present invention includes a third resistor having one end connected to the other end of the first resistor and the other end connected to a load, and a load current for detecting a load current to the load by the third resistor. Detection means; load current determination means for determining whether or not the load current is greater than a fifth current value; and timing means for measuring an elapsed time since the transition to the charging current charge control. The determination means has a configuration in which when the load current is equal to or greater than the fifth current value, the charge control means continuously executes the charge current limiting charge control until the time measuring means passes a preset time. is doing.

  With this configuration, it is possible to prevent the transition from the charging current limit charging control to the constant voltage charging control in a state where the charging rate of the battery is low.

  In the charging control apparatus of the present invention, the load current determination unit receives threshold information indicating the fifth current value from the load.

  With this configuration, it is possible to prevent the transition from the charging current limit charging control to the constant voltage charging control in a state where the charging rate of the battery is low.

  An electronic apparatus according to the present invention has a configuration including the charge control device according to any one of claims 1 to 8.

  With this configuration, even when a device is used during charging, it is possible to accurately control the charging voltage and detect the charging current while limiting heat generation during charging.

  The charge control method of the present invention is a charge control method that is interposed between an external power source and a battery and controls the charging current of the battery, and is configured to reduce the current from the external power source until the voltage of the battery reaches a predetermined voltage. When constant current charging control is performed to suppress the current to a first current value, and the voltage of the battery reaches a predetermined voltage, the current from the external power source is smaller than the first current value while keeping the voltage of the battery constant. Transition to charge current limit charge control to limit to two current values or less, intermittently release the charge current limit charge control, detect the charge current of the battery when the charge current limit charge control is cancelled, When the charging current of the battery becomes equal to or lower than the third current value, the battery voltage is shifted to constant voltage charging control for keeping the voltage of the battery constant.

  With this configuration, it is possible to accurately control the charging voltage and detect the charging current while restricting heat generation during charging.

  In the charging control method of the present invention, it is determined whether the charging current of the battery is equal to or lower than a fourth current value smaller than the third current value, and the charging current of the battery is equal to or lower than the fourth current value. When the current from the external power source is stopped, the constant voltage charging control is completed.

  With this configuration, it is possible to prevent the transition from the charging current limit charging control to the constant voltage charging control in a state where the charging rate of the battery is low.

  The charge control method of the present invention detects a load current to the load from the current from the external power source and the charge current of the battery, and when the load current is equal to or greater than the fifth current value, the charge current of the battery is The charging current limit charging control is continuously executed until the third current value or less is reached.

  With this configuration, it is possible to prevent the transition from the charging current limit charging control to the constant voltage charging control in a state where the charging rate of the battery is low. Further, the configuration can be simplified because a component for detecting the load current is not required.

  The charge control method of the present invention detects a load current to the load from the current from the external power source and the charge current of the battery, and sets a preset time when the load current is equal to or greater than the fifth current value. The charging current limiting charging control is continuously executed until a lapse of time.

  With this configuration, it is possible to prevent the transition from the charging current limit charging control to the constant voltage charging control in a state where the charging rate of the battery is low.

  The present invention provides a charge control device and a charge control method capable of accurately controlling a charging voltage and detecting a charging current while limiting heat generation during charging even when a device is used during charging. It is something that can be done.

  Hereinafter, a charge control device and a charge control method according to an embodiment of the present invention will be described with reference to the drawings.

(First embodiment)
FIG. 1 is a block diagram showing the configuration of the charge control device according to the first embodiment of the present invention. As shown in FIG. 1, the charge control device includes a battery voltage detection means 109 for detecting the voltage of the battery 11, a charge current detection means 103 for detecting a current from the external power source 13 and a charge current of the battery 11, and a battery. The constant current charging control is performed to suppress the current from the external power source 13 to the first current value until the voltage of the battery 11 reaches the predetermined voltage. When the voltage of the battery 11 reaches the predetermined voltage, the voltage of the battery 11 is kept constant. Charging control means 107 for shifting to charging current limiting charging control for limiting the current from the external power source 13 to a second current value lower than the first current value while maintaining the charging current of the battery 11 smaller than the second current value. Charging current determination means 151 for determining whether or not the current value is equal to or less than three current values.

  The charging current detection means 103 detects the charging current of the battery 11 when the charging current limit charging control is released intermittently.

  When the charging current of the battery 11 becomes equal to or lower than the third current value, the charging control means 107 shifts to constant voltage charging control that keeps the voltage of the battery 11 constant.

  The charging current determination unit 151 determines whether or not the charging current of the battery 11 is equal to or lower than a fourth current value that is smaller than the third current value, and the charging control unit 107 determines that the charging current of the battery 11 is equal to or lower than the fourth current value. At this time, the current from the external power supply 13 is stopped and the constant voltage charging control is completed.

  The charge control device also includes a first resistor 101 having one end connected to the battery 11, a second resistor 102 having one end connected to the other end of the first resistor 101, and a first terminal connected to the external power supply 13. And a second terminal connected to the second resistor 102, and an FET (current limiting element) 105 that outputs a current from the external power supply 13 to the second resistor 102.

  Since a load is always connected to the battery 11, when the battery 11 is charged, as shown in FIG. 7, a current 501 from the external power source 13 includes a charging current 502 of the battery 11 and a load current 503 flowing through the load. The sum of

The charging current detection means 103 detects the current from the external power supply 13 with the second resistor 102 and detects the charging current of the battery 11 with the first resistor 101 .

The charge control means 107 adjusts the voltage applied to the gate of the FET 105 so as to limit the current flowing between the drain and source, and executes constant current charge control , constant voltage charge control , and charge current limit charge control. Yes.

The time measuring means 309 measures the time during which the charging current limiting charging control is executed when the charging control means 107 executes the charging current limiting charging control . On the other hand, when the charging current limiting charging control is executed, the charging control unit 107 starts the time counting unit 309 and executes the charging current limiting charging control until a preset time elapses.

The charging current limiting charging control is control for limiting the voltage of the battery 11 to a predetermined voltage and limiting the upper limit value of the charging current to a predetermined value or less.

  Next, the operation of the charge control device of the present embodiment will be described.

As shown in FIG. 8, the charging control means 107 responds to a signal 601 from the time measuring means 309 (the section for canceling the charging current limited charging control is shown) and charges for a certain time 603 (T1). Release the current limit charge control . On the other hand, the charging current determination unit 151 responds to a signal 602 from the time measuring unit 309 (a signal indicating a section for comparing charging currents), and a period 604 (T2) in which the charging control unit 107 cancels the charging current limiting charging control. a) compares the charging current and the predetermined value of the battery 11 detected by the charging current detection unit 103, the interval in which the charging control unit 107 executes a charging current limiting charging control, the charging current of the battery 11 with a predetermined value Do not perform comparisons.

By the signals 601 and 602, the charging current determination unit 151 compares the charging current after the charging control unit 107 cancels the charging current limiting charging control, and executes the charging current limiting charging control after the comparison of the charging current is completed. is doing. T1> T2 is set so that the charging current of the battery 11 is not compared with a predetermined value during the period in which the charging control unit 107 executes the charging current limiting charging control .

  As described above, the charging control device according to the present embodiment detects the charging current of the battery when the charging current limiting charging control is intermittently released. While limiting, it is possible to accurately control the charging voltage and detect the charging current.

  In addition, since the charging control device shifts to constant voltage charging control that keeps the battery voltage constant when the charging current of the battery becomes the third current value or less, the charging current limiting charging is performed in a state where the charging rate of the battery is low. Transition from control to constant voltage charge control can be prevented.

  In the charging control device, the charging current determining unit determines whether or not the charging current of the battery is equal to or lower than a fourth current value smaller than the third current value, and the charging control unit determines that the charging current of the battery is fourth. When the current value becomes lower than the current value, the current from the external power supply is stopped and the constant voltage charging control is completed. Therefore, it is possible to prevent the constant voltage charging control from being completed when the charging rate of the battery is low.

  The charge control method according to the present embodiment is a charge control method that is interposed between an external power source and a battery and controls the charge current of the battery, and the current from the external power source until the battery voltage reaches a predetermined voltage. When the battery voltage reaches a predetermined voltage, the current from the external power source is smaller than the first current value while maintaining the battery voltage constant. The battery charging current is detected when the charging current limiting charging control is released, the charging current limiting charging control is intermittently canceled, and the charging current limiting charging control is canceled. When the current becomes 3 current values or less, the control shifts to constant voltage charging control that keeps the battery voltage constant. With this configuration, the charging voltage is controlled and charged while limiting the heat generation during charging. It is possible to detect the current accurately.

  In addition, the charge control method determines whether or not the battery charging current is equal to or smaller than a fourth current value smaller than the third current value, and when the battery charging current is equal to or smaller than the fourth current value, Since the constant current charge control is completed, the transition from the charge current limited charge control to the constant voltage charge control can be prevented in a state where the charge rate of the battery is low.

(Second Embodiment)
A charging control apparatus according to the second embodiment of the present invention will be described with reference to FIG. Among the components of the charge control device according to the second embodiment, the same components as those of the charge control device according to the first embodiment are denoted by the same reference numerals and description thereof is omitted.

  As shown in FIG. 2, the charge control device includes a first resistor 101, a second resistor 102, a third resistor 301, a charge current detection means 103, an FET 105, a charge control means 107, and a battery voltage detection means. 109, a charging current determination unit 151, a load current detection unit 303, a load current determination unit 305, and a timing unit 309.

  The third resistor 301 is an element necessary for detecting the current flowing to the load.

  The load current detection unit 303 detects a voltage drop at the third resistor 301 and calculates a load current output to the load via the third resistor 301.

  The load current determination unit 305 determines whether or not the current of the third resistor 301 exceeds a preset threshold value.

When the load current is equal to or greater than the fifth current value, the load current determining means 305 causes the charge control means 107 to continuously execute the charge current limiting charge control until the charge current of the battery 11 becomes equal to or less than the third current value. It has become.

Here, when the load current is greater than or equal to the fifth current value, the load current determination unit 305 causes the charge control unit 107 to continuously execute the charge current limiting charge control until the time measuring unit 309 passes a preset time. You may do it.

  Next, the operation of the charge control device of the present embodiment will be described.

  It is detected by the load current determination means 305 whether or not the load current is in a large state. For example, when the third resistor 301 and the load current detection unit 303 detect the load current as 200 mA and the threshold value for determining that the load current is large is 100 mA, the load current determination unit 305 indicates that the load current is large. Is transmitted to the charging control means 107 and the charging current determination means 151, and the charging current limiting and the charging current detection are intermittently performed in the charging current limiting charging control.

  As described above, the charging control device of the present embodiment detects the current from the external power source with the first resistor and detects the charging current of the battery with the second resistor, so that the charging rate of the battery is low. It is possible to prevent the transition from the charge current limit charge control to the constant voltage charge control.

  In addition, when the load current is equal to or greater than the fifth current value, the charge control device according to the present embodiment continuously performs the charge current limiting charge control until the charge current of the battery becomes equal to or less than the third current value. It is possible to prevent the transition from the charging current limit charging control to the constant voltage charging control in a state where the charging rate is low.

  In addition, when the load current is greater than or equal to the fifth current value, the charge control device according to the present embodiment continuously performs the charge current limit charge control until a preset time elapses. It is possible to prevent transition from charge current limit charge control to constant voltage charge control in a low state.

(Third embodiment)
With reference to FIG. 3, a charge control apparatus according to a third embodiment of the present invention will be described. Among the components of the charge control device according to the third embodiment, the same components as those of the charge control device according to the first embodiment are denoted by the same reference numerals and description thereof is omitted.

  As shown in FIG. 3, the charge control device includes a first resistor 101, a second resistor 102, a charge current detection means 103, an FET 105, a charge control means 107, a battery voltage detection means 109, and a charge current determination. Means 151, load current detection means 303, load current determination means 305, and timing means 309 are provided.

  The load current detecting means 303 detects the load current to the load from the current from the external power source 13 and the charging current of the battery 11.

  For example, when the current of the first resistor 101 is 200 mA (in the direction of flowing into the battery 11) and the current of the second resistor 102 is 500 mA, the current flowing through the load can be detected as 500 mA−200 mA = 300 mA.

  The load current determination unit 305 determines whether or not the load current is smaller than the fifth current value. When the load current is equal to or larger than the fifth current value, the charge control is performed until the charging current of the battery 11 becomes equal to or smaller than the third current value. The means 107 is configured to continuously execute the charging current limit charging control.

  In addition, when the load current is equal to or greater than the fifth current value, the load current determination unit 305 causes the charge control unit 107 to continuously execute the charge current limiting charge control until the time measuring unit 309 passes a preset time. It may be.

  For example, if the current output to the load is 200 mA and the preset current value is 100 mA, the current output to the load exceeds the preset current value. Comparisons are made intermittently.

  As described above, when the load current is equal to or greater than the fifth current value, the charge control device according to the present embodiment continuously performs the charge current limiting charge control until the battery charge current becomes equal to or smaller than the third current value. Therefore, it is possible to prevent the transition from the charging current limit charging control to the constant voltage charging control in a state where the charging rate of the battery is low.

  When the load current is equal to or greater than the fifth current value, the charge control device according to the present embodiment continuously executes the charge current limit charge control until a preset time has elapsed, so that the battery charge rate is low. Thus, it is possible to prevent the transition from the charging current limit charging control to the constant voltage charging control.

(Fourth embodiment)
A charging control apparatus according to a fourth embodiment of the present invention will be described with reference to FIG. Among the components of the charge control device according to the fourth embodiment, the same components as those of the charge control device according to the first embodiment are denoted by the same reference numerals and description thereof is omitted.

  As shown in FIG. 4, the charging control device includes a first resistor 101, a second resistor 102, a charging current detecting unit 103, an FET 105, a charging control unit 107, a battery voltage detecting unit 109, and a time measuring unit 309. And charging current determination means 151.

  In the present embodiment, the load (apparatus) 307 includes load current determination means 311 for determining whether or not the load current exceeds a preset threshold value. The load current determination means 311 has a table in which the load current value of each operation mode of the load 307 is shown, and the consumption current of the load 307 is determined using this table.

  The charging control device of the third embodiment is that the load current determination means 311 of the load 307 determines the magnitude of the load current in each operation mode of the external device. Is different.

  For example, when the load current value in the voice call mode is 200 mA and the preset threshold is 100 mA, it is determined that the load current is in a large state. On the other hand, the charging control unit 107 intermittently executes the charging current limiting charging control based on the determination result of the load current determination unit 311.

  As described above, in the charge control device of the present embodiment, the load current determination unit of the load determines whether or not the load current exceeds a preset threshold value. Since the effect similar to the effect which the charge control apparatus which concerns on embodiment of this invention show | plays can be acquired, and the element which detects a load current is not required, a circuit can be simplified.

  As described above, the charging control device according to the present invention has the effect of accurately controlling the charging voltage and detecting the charging current while restricting heat generation during charging, and is driven by a secondary battery. Useful for.

The block diagram which shows the structure of the charge control apparatus which concerns on the 1st Embodiment of this invention. The block diagram which shows the structure of the charge control apparatus which concerns on the 2nd Embodiment of this invention. The block diagram which shows the structure of the charge control apparatus which concerns on the 3rd Embodiment of this invention. The block diagram which shows the structure of the charge control apparatus which concerns on the 4th Embodiment of this invention. Block diagram showing the configuration of a conventional charge control device Characteristic diagram showing the change in charge current from constant current charge control to constant voltage charge control The figure where each current flow of the charge control device of the present invention was shown typically A signal indicating a section in which the charge control means of the charge control device of the first to third embodiments of the present invention cancels the charge current limited charge control, and the charge current detection means detects the charge current, and the charge current The chart figure in which the timing with the signal in which the determination means compares the charging current is shown

Explanation of symbols

DESCRIPTION OF SYMBOLS 11 Battery 13 External power supply 101 1st resistance 102 2nd resistance 103 Charging current detection means 105 FET (current limiting means)
107 charge control means 109 battery voltage detection means 151 charge current determination means 301 third resistor 303 load current detection means 305 load current determination means 307 load (device)
309 Timekeeping means 311 Load current determination means 401 Time change of charge current in charge control method before heat generation countermeasure 402 Time change of charge current in charge control method 403 Charge current limit Limit value of charge current in charge control (second Current value)
501 current 502 Battery charging current 503 load current 601 charging current limiting charging control the release to interval indicated signal 602 signal 603 charge current limit charging control is the section for comparing a charging current indicated to the load from the external power source 604 to cancel the charge Interval to compare the charging current

Claims (14)

A charge control device that is interposed between an external power source and a battery and controls a charging current of the battery,
Battery voltage detection means for detecting the voltage of the battery;
Charging current detecting means for detecting a current from the external power source and a charging current of the battery;
A constant current charge control is performed to keep the current from the external power source at a first current value until the battery voltage reaches a predetermined voltage. When the battery voltage reaches a predetermined voltage, the battery voltage is kept constant. Charge control means for transitioning to charge current limit charge control for limiting the current from the external power source to a second current value smaller than the first current value or less while maintaining
The charging control device according to claim 1, wherein the charging current detecting means detects a charging current of the battery when the charging current limiting charging control is intermittently released. Charging current determining means for determining whether or not the charging current of the battery has become equal to or smaller than a third current value smaller than the second current value;
The charging control means shifts to constant voltage charging control that keeps the voltage of the battery constant without limiting the current from the external power source when the charging current of the battery becomes equal to or less than the third current value. The charge control device according to claim 1, wherein: The charging current determining means determines whether or not the charging current of the battery is equal to or lower than a fourth current value smaller than the third current value;
3. The charge control unit according to claim 2, wherein when the charging current of the battery becomes equal to or lower than the fourth current value, the charging control unit stops the current from the external power source and completes the constant voltage charging control. The charging control device described. Load current detection means for detecting a load current to the load from the current from the external power supply and the charging current of the battery;
Load current determining means for determining that the load current is large when the load current is larger than a fifth current value that is a predetermined threshold for use in determining whether or not the load current is large. ,
When the load current determination unit determines that the load current is large , the load current determination unit causes the charge control unit to continuously execute the charge current limiting charge control until a charge current of the battery becomes equal to or less than the third current value. The charge control device according to claim 3. Load current detection means for detecting a load current to the load from the current from the external power supply and the charging current of the battery;
Load current determining means for determining that the load current is large when the load current is larger than a fifth current value that is a predetermined threshold for use in determining whether or not the load current is large ;
Comprising time measuring means for measuring the elapsed time since the transition to the charging current charging control,
When the load current determination unit determines that the load current is large , the load current determination unit causes the charge control unit to continuously execute the charge current limiting charge control until a predetermined time elapses. The charge control device according to claim 3. A first resistor having one end connected to the battery;
A second resistor having one end connected to the other end of the first resistor;
A first terminal connected to the external power source and a second terminal connected to the second resistor; and a current limiting element that outputs a current from the external power source to the second resistor.
The charging current detection means detects a current from the external power source with the second resistor, and detects a charging current of the battery with the first resistor. Charge control device. A third resistor having one end connected to the other end of the first resistor and the other end connected to a load;
Load current detection means for detecting a load current to the load with the third resistor;
Load current determining means for determining that the load current is large when the load current is larger than a fifth current value that is a predetermined threshold for use in determining whether or not the load current is large. ,
When the load current determination unit determines that the load current is large , the load current determination unit causes the charge control unit to continuously execute the charge current limiting charge control until a charge current of the battery becomes equal to or less than the third current value. The charge control device according to claim 6. A third resistor having one end connected to the other end of the first resistor and the other end connected to a load;
Load current detection means for detecting a load current to the load with the third resistor;
Load current determining means for determining that the load current is large when the load current is larger than a fifth current value that is a predetermined threshold for use in determining whether or not the load current is large ;
Comprising time measuring means for measuring the elapsed time since the transition to the charging current charging control,
When the load current determination unit determines that the load current is large , the load current determination unit causes the charge control unit to continuously execute the charge current limiting charge control until a predetermined time elapses. The charge control device according to claim 6.   The charge control device according to claim 7 or 8, wherein the load current determination unit receives threshold information indicating the fifth current value from the load.   An electronic device comprising the charge control device according to any one of claims 1 to 8. A charge control method for interposing between an external power source and a battery and controlling a charging current of the battery,
A constant current charge control is performed to suppress the current from the external power source to the first current value until the battery voltage reaches a predetermined voltage,
When the voltage of the battery reaches a predetermined voltage, the process shifts to charge current limit charge control for limiting the current from the external power source to a second current value smaller than the first current value while keeping the battery voltage constant. And
The charge current limit charge control is intermittently released, and when the charge current limit charge control is released, the charge current of the battery is detected,
When the charging current of the battery becomes equal to or less than the third current value, the battery voltage shifts to constant voltage charging control that keeps the voltage of the battery constant without limiting the current from the external power source . Charge control method. Determining whether the charging current of the battery is equal to or less than a fourth current value smaller than the third current value;
The charging control method according to claim 11, wherein when the charging current of the battery becomes equal to or less than the fourth current value, the current from the external power supply is stopped and the constant voltage charging control is completed. Detecting a load current to the load from the current from the external power source and the charging current of the battery,
When the load current is equal to or greater than a fifth current value that is a predetermined threshold for use in determining whether the load current is large, it is determined that the load current is large, and the charging current of the battery is The charge control method according to claim 12, wherein the charge current limit charge control is continuously executed until the current value becomes equal to or less than a third current value. Detecting a load current to the load from the current from the external power source and the charging current of the battery,
When the load current is equal to or greater than the fifth current value, which is a predetermined threshold for use in determining whether the load current is large, the load current is determined to be large, and a preset time is determined. The charge control method according to claim 12, wherein the charge current limit charge control is continuously executed until a lapse of time.

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