JP2008167543A - Charge control device, portable terminal device, and charge control method - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a charge control device wherein overcharging of a secondary battery can be constantly prevented. <P>SOLUTION: The charge control device includes: an external power supply detection unit 101 that detects an external power supply 200 supplying power to a secondary battery 300; a secondary battery voltage detection unit 102 that detects the voltage of the secondary battery 300; and a charge control unit 103 that prohibits charging of the secondary battery 300 by the external power supply 200 when the external power supply 200 is detected by the external power supply detection unit 101 and the voltage of the secondary battery 300 is higher than a predetermined charge determination voltage used when the external power supply 200 is detected. As a result, it is possible to constantly prevent overcharging of the secondary battery and lengthen the life of the battery. <P>COPYRIGHT: (C)2008,JPO&INPIT

Description

  The present invention relates to a charge control device that controls charging of a secondary battery, a portable terminal device, and a charge control method.

  In charging the secondary battery, charging is generally started when the battery is set in the charger, and charging is terminated in a state where the battery is fully charged. FIG. 6 is a schematic diagram of a conventional charging system. A conventional charging system includes an external power source 601, a charge FET (Field Effect Transistor) 602, a resistor 603, a secondary battery 604, and a charge control unit 605. In this charging system, the charging control unit 605 is configured to always start charging the secondary battery 604 when the external power source 601 is applied or when the voltage of the secondary battery 604 falls below a predetermined threshold. Control is in progress.

In addition, even if a secondary battery is set in the charger, the temperature of the secondary battery is detected via a thermistor, an A / D converter, and a battery temperature calculation unit so as not to start charging immediately. A timer for measuring the elapsed time after the end of the quick charge of the secondary battery is provided, the battery temperature detected when the secondary battery is set in the charging device is equal to or higher than a predetermined value, and the elapsed time measured by the timer 2. Description of the Related Art A secondary battery charging device having a charging control unit that prohibits rapid charging when the value is less than a predetermined value is known (see, for example, Patent Document 1).
JP 2004-102339 A

  However, since the secondary battery charging device described in Patent Document 1 tries to prevent overcharging only when the temperature is abnormal by temperature detection, when the temperature of the secondary battery is a normal value, The overcharge cannot be prevented regularly.

  The present invention has been made in view of such circumstances, and an object of the present invention is to provide a charge control device, a portable terminal device, and a charge control method capable of regularly preventing overcharge of a secondary battery. .

  In order to achieve the above object, a first charge control device of the present invention includes an external power supply detection unit that detects an external power supply that supplies power to a secondary battery, and a secondary battery that detects the voltage of the secondary battery. When the external power source is detected by the voltage detection unit and the external power source detection unit, and the voltage of the secondary battery is higher than a predetermined charge determination voltage used when the external power source is detected, the external power source And a charging control unit that prohibits charging of the secondary battery.

  According to this configuration, it is possible to prevent the secondary battery from being overcharged steadily and extend the battery life.

  The second charge control device of the present invention is configured such that, when the external power source is detected by the external power source detection unit, the charge control unit causes the presentation unit to present that the external power source has been detected. .

  With this configuration, it is possible to notify the user that the external power source has been connected even when charging is not actually performed even though the external power source is connected.

  In the third charge control device of the present invention, when the charge control unit has passed a predetermined time after the external power source is detected by the external power source detection unit, or the voltage of the secondary battery is the charge When at least one of the cases where the voltage is lower than a predetermined charging restart voltage lower than the determination voltage is satisfied, the secondary battery is charged from the external power source.

  With this configuration, for example, even when charging is not performed when an external power supply is connected, charging can be performed after a certain period of time or when the remaining battery capacity becomes insufficient, and necessary power can always be secured. Is possible.

  Moreover, the 4th charge control apparatus of this invention has the charge completion voltage setting part which sets the charge completion voltage for completing the charge to the said secondary battery, The said charge control part is the said secondary battery. The charging is performed until the charging completion voltage is reached.

  With this configuration, it is possible to prevent the battery from being always charged until it is fully charged by flexibly setting a desired charge completion voltage by the user, and to extend the battery life.

  The fifth charge control device of the present invention includes a control mode designating unit that designates a control mode indicating which control is performed by the charge control unit, and the charge control unit enters the control mode. It is set as the structure which performs control based on.

  With this configuration, by setting the desired control mode flexibly by the user, various charging controls can be performed, and comfortable charging can be performed according to the environment in which the user is placed.

  Moreover, the 1st portable terminal device of this invention is set as the structure which has one of the said charge control apparatuses.

  With this configuration, it is possible to provide a portable terminal device that can regularly prevent overcharge of the secondary battery and extend the battery life.

  The first charge control method of the present invention includes an external power supply detection step of detecting an external power supply that supplies power to the secondary battery in a charge control device that controls charging of the secondary battery; A step of detecting a voltage of the battery, and when the external power supply is detected in the external power supply detection step and the voltage of the secondary battery is higher than a predetermined charge determination voltage, the external power supply to the secondary battery And a step of controlling to prohibit charging.

  By this method, it is possible to prevent overcharge of the secondary battery on a regular basis and extend the battery life.

  ADVANTAGE OF THE INVENTION According to this invention, the overcharge to a secondary battery can be prevented regularly and a battery life can be extended.

  Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings.

  FIG. 1 is a block diagram illustrating a configuration of the charging control apparatus 100. The charging control device 100 includes an external power source detection unit 101, a secondary battery voltage detection unit 102, a charging control unit 103, an input unit 104, an LED 105, and a communication unit 106. It is also possible to mount the charging control device 100 on a mobile terminal device such as a mobile phone.

  Further, the input unit 104 has functions as a “charging completion voltage setting unit” and a “control mode designation unit”. The LED 105 is an example of a “presentation unit”.

  The external power source detection unit 101 detects whether or not an external power source (for example, a 100 V commercial AC power source) 200 that supplies power to the secondary battery 300 is applied. The detection of application of the external power supply 200 is performed by sequentially detecting the external power supply voltage, for example. The secondary battery voltage detection unit 102 detects the voltage at that time of the secondary battery 300 such as a lithium ion secondary battery. The charging control unit 103 performs various controls when power is supplied from the external power source 200 to the secondary battery 300, and details of the function will be described later. The input unit 104 is used by a user who performs charging to input various types of information in order to arbitrarily perform various settings, such as a touch panel or a keyboard. The input unit 104 includes a charging completion voltage for completing the charging of the secondary battery 300, a control mode related to charging (a battery eco mode for operating the charging control device 100 with as little power consumption as possible, a secondary battery stamina mode) Etc.) and other information. The LED 105 is a light emitter that emits light when a predetermined condition is satisfied. The communication unit 106 performs communication for charging with other communication devices using a wired signal such as USB, and also communicates with other communication devices using a wireless signal such as infrared rays. Communication for charging between.

Next, charging control using voltage values performed by the charging control unit 103 will be described.
FIG. 2 is a diagram for explaining a charge control method based on the secondary battery voltage performed by the charge control unit 103. Note that “LED lighting” in FIG. 2 indicates whether or not the LED 105 is lit regardless of whether charging is actually performed, “ON” indicates that the LED 105 is lit, and “OFF” indicates that the LED 105 is lit. Indicates that it is turned off.

  When the external power supply detection unit 101 detects that the external power supply voltage is applied by the external power supply 200, the charge control unit 103 detects that the predetermined charge determination voltage (VM) used when the external power supply voltage is applied is more than the predetermined charge determination voltage (VM). When the secondary battery voltage is low, the secondary battery 300 is charged from the external power source 200 (see time a1). This charging is performed until the charging completion voltage (VH) is reached (until time a2). In addition, during the charging period, the charging control unit 103 controls the LED 105 to emit light so that the charging can be recognized.

  The charge determination voltage is a threshold value for determining whether or not to charge the secondary battery 300 when the external power supply detection unit 101 newly detects application of the external power supply 200. If the secondary battery voltage is higher than the charge determination voltage, charging is not performed, and if the secondary battery voltage is low, charging is performed.

  When the secondary battery voltage again falls below a predetermined charge restart voltage (VL) due to the use of the secondary battery 300 or the like, the charge control unit 103 at the time when the secondary battery voltage becomes lower than the charge restart voltage. Starts charging again (see time a3). This recharging is performed until the charging completion voltage is reached (until time a4).

  It should be noted that the charge restart voltage refers to whether the secondary battery 300 is charged when the external power supply detection unit 101 detects that the external power supply 200 is continuously applied even after the charging is completed. It is a threshold value for determining whether or not. If the secondary battery voltage is higher than the charge determination voltage, charging is not performed, and if the secondary battery voltage is low, charging is performed.

  When the external power supply is temporarily interrupted (see time a5) and then the external power supply detection unit 101 detects the application by the external power supply 200, the secondary battery voltage at that time is higher than the charge determination voltage. Is higher and lower than the charging completion voltage, that is, when the secondary battery voltage is in the range between the arrows in C1 in FIG. 2, the charging control unit 103 switches from the external power source 200 to the secondary battery 300. Control is performed so that charging is not performed (see time a6). Further, during a predetermined time period (for example, 10 seconds) from time a6 to time a7 when the external power supply detection unit 101 detects application of the external power supply 200, the charging control unit 103 controls the LED 105 to emit light (FIG. 2 in C2). In order to recognize the difference between the light emission of the LED 105 indicating that charging is being performed and the LED 105 indicating that the application of the external power source 200 has been detected although charging to the secondary battery 300 is not performed, The emission color can be changed. Furthermore, it is not limited to the color development of the LED 105, but it is also possible to notify the user of the state by voice or the like.

  The application of the external power source 200 is temporarily interrupted (see time a8), and then the external power source detection unit 101 detects the application by the external power source 200, and the secondary battery voltage at that time is a predetermined charge. When the voltage is lower than the restart voltage, the charging control unit 103 charges the secondary battery 300 from the external power source 200 (see time a9). This charging is performed until the secondary battery voltage reaches the charging completion voltage (until time a10).

  In this way, for example, even when the external power source 200 is attached to a charging device to charge the secondary battery 300, the secondary battery voltage at that time is lower than the charge completion voltage and the charge determination voltage If the external power supply 300 is higher than the external power supply 300, charging is not performed even when the external power supply 300 is applied. It is possible.

  Further, for example, when the external power source 200 is attached to a charging device for charging, the LED 105 is lit regardless of whether or not charging is performed, and the user is informed that the external power source 200 is attached. Is possible.

  Next, charging control using a timer (not shown in FIG. 1) performed by the charging control unit 103 will be described. FIG. 3 is a diagram for explaining a charge control method based on a timer performed by the charge control unit 103. In charge control using a timer, the charge determination voltage which is the threshold described above is not taken into consideration, and the charge restart voltage also has a role as the charge determination voltage. The charging control unit 103 has a timer function for managing time.

  Further, “LED ON” in FIG. 3 indicates whether the LED 105 is ON regardless of whether charging is actually performed, “ON” indicates that the LED 105 is ON, and “OFF” indicates that the LED 105 is ON. Indicates that it is turned off. The “charging mode” indicates whether or not charging is actually being performed, “ON” indicates that charging is in progress, and “OFF” indicates that charging is not in progress.

  When the external power source detection unit 101 detects that an external power source is applied by the external power source 200, the charge control unit 103 starts from the external power source 200 when the secondary battery voltage is lower than a predetermined charging restart voltage. The secondary battery 300 is charged (see time b1). This charging is performed until the charging completion voltage is reached (until time b2). In addition, during the charging period, the charging control unit 103 controls the LED 105 to emit light so that the user can recognize that charging is being performed.

  The application of the external power source 200 is temporarily interrupted (see time b3), and then the external power source detection unit 101 detects the application by the external power source 200, and the level of the secondary battery voltage at that time is the charge restart When the voltage is higher than the voltage and lower than the charging completion voltage, the charging control unit 103 performs control so as not to charge the secondary battery from the external power source (see times b4 and C3). In addition, the user recognizes that the application of the external power supply 200 is detected during a T2 period from a time b4 to a time b5 when the external power supply detection unit 101 detects the application of the external power supply 200 (for example, 10 seconds). For this reason, the charging control unit 103 controls the LED 105 to emit light. The elapse of the T2 period is monitored by the charge control unit 103 measuring time. In order to recognize the difference between the light emission of the LED 105 indicating that charging is being performed and the LED 105 indicating that the application of the external power source 200 has been detected although charging to the secondary battery 300 is not performed, The emission color can be changed.

  The charging control unit 103 measures the elapsed time with the time b4 when the external power supply detection unit 101 detects the application of the external power supply 200 as the start time of the elapsed time measurement. When the charging control unit 103 recognizes that a predetermined T1 period (for example, 24 hours) has elapsed since the start of application of the external power supply, charging is performed even when the secondary battery voltage at that time is higher than the charging restart voltage. Is started (see time b6, C4). Here, the period from the time b4 to the time b6 when the application start time of the external power supply 200 corresponds to the T1 period. This charging is performed until the secondary battery voltage reaches the charging completion voltage (until time b7).

  Note that the T1 period is related to the level of the secondary battery voltage from the time when the application of the external power source 200 is detected or the time when the charging to the secondary battery 300 is completed although the secondary battery is not charged. It is a predetermined period until the next charging is started. Note that the charging control unit 103 resets the measurement of the elapsed time when charging of the secondary battery 300 is started during the measurement of the elapsed time of the T1 period.

  When the secondary battery voltage again falls below a predetermined charge restart voltage due to the use of the secondary battery 300 or the like, the time T1 elapses from the application start time (time b7) of the external power source 200, that is, the time b9. Even before, the charging control unit 103 charges the secondary battery 300 from the external power source 200 (see times b8 and C5). This charging is performed until the secondary battery voltage reaches the charging completion voltage (until time b10).

  The charging control unit 103 measures the elapsed time with the time b10 when the charging of the secondary battery 200 is completed as the start time of the elapsed time measurement. The secondary battery voltage at time b11, which is the end point of the T1 period, is higher than the charging restart voltage, but the charging control unit 103 charges the secondary battery 300 from the external power source 200 (see C6).

  As described above, when the external power source 200 is applied within a predetermined period and the voltage of the secondary battery 200 at that time is equal to or higher than the charging restart voltage, the charging control unit 103 is not charged. It is possible to control, and it is possible to prevent overcharge constantly. In addition, when the state in which the external power source 200 is not charged for a certain period of time has continued after the external power source 200 is applied, the charge control unit 103 charges the secondary battery 300 from the external power source 200 regardless of the voltage of the secondary battery 200 at that time. Can be done. Further, even if the voltage of the secondary battery 200 at that time is lower than the charge restart voltage even within a predetermined period after the external power supply 200 is applied, the charge control unit 103 is connected to the external power supply 200 from the external power supply 200. The secondary battery 300 can be charged.

Next, the setting by the user of the charging completion voltage will be described.
The procedure for changing the charge completion voltage is as follows. First, when the input unit 104 inputs a desired charge completion voltage (desired voltage) in accordance with a user instruction for charging, the charge control unit 103 sets the input desired voltage. recognize. The charging control unit 103 changes the charging completion voltage at that time to the desired voltage recognized.

  Here, FIG. 4A shows time-voltage characteristics according to each charging completion voltage. In FIG. 4A, the characteristic of a curve 401 is a characteristic when the charge completion voltage for charging up to 100% of the battery capacity (full charge) is the charge completion voltage A. For example, the charge completion voltage A is 4 .2V. The characteristic of the curve 402 is a characteristic when the charge completion voltage for charging up to about 90% of the battery capacity is the charge completion voltage B. For example, the charge completion voltage B is 4.1V. In the curve 401 and the curve 402, the difference in charging time from 0 V to the charging completion voltage is almost the same.

  However, as shown in FIG. 4B, the battery capacity characteristic with respect to the number of cycles based on the number of times of charging is larger than that when the charging completion voltage A is set (corresponding to the curve 403) as the number of cycles increases. When the completion voltage B is set (corresponding to the curve 404), the battery capacity tends to decrease less. This is because, in the case of the charging completion voltage B, charging is terminated in a voltage state that is always lower than the full charging voltage during charging. FIG. 4B shows the cycle number capacity characteristics for each charge completion voltage. By selecting the charge completion voltage B as the charge completion voltage, the battery life can be further extended. For example, if the charge completion voltage A is 4.2 V and the charge completion voltage B is 4.1 V, the life of the secondary battery 300 is approximately 1.3 times longer.

  In this way, it is possible to select different charge completion voltages as desired by the user. For example, the charging completion voltage B is normally selected, and the charging completion voltage A is selected in a situation where the charging operation cannot be performed for a certain period of time. It is also possible to extend the life of the secondary battery 300 while ensuring a sufficient battery capacity. The charge completion voltage is not limited to the two types of charge completion voltage A and charge completion voltage B, and there may be more types.

  In addition, the charging completion voltage can be set based on various charging conditions (for example, external charging conditions such as USB charging and non-contact charging not shown) instead of setting the charging completion voltage by the user. For example, the communication unit 106 receives a charging signal including information on a charging completion voltage transmitted from an external power source 200 that is a charging source connected by USB or an external power source 200 that can be connected by wireless communication, and detects an external power source. This can be realized by the unit 101 detecting this charging signal and the charging control unit 103 changing the charging completion voltage based on this charging signal.

  Next, each operation of the charging control apparatus 100 described so far will be described based on a case where the charging control apparatus 100 operates in a control mode desired by the user based on an input of the input unit 104 according to a user instruction.

  For example, the input unit 104 inputs in accordance with a user instruction so as to perform charge control using a voltage value as shown in FIG. 2, and based on this, the charge control unit 103 performs charge control using the voltage value. Transition to control mode. Further, if there is no input from the input unit 104, the charging control unit 103 can be prevented from shifting to this control mode.

  For example, even when charging is not performed, the input unit 104 inputs a user instruction to turn on the LED 105 for a certain period of time when an external power supply is applied, and even when the charging control unit 103 is not charged based on the input, The system shifts to a control mode in which the LED 105 is lit for a certain time when power is applied. Further, if there is no input from the input unit 104, the charging control unit 103 can be prevented from shifting to this control mode.

  Further, for example, the input unit 104 inputs in accordance with a user instruction so as to perform charge control using a timer as shown in FIG. 3, and based on this, the charge control unit 103 performs charge control using the timer. Transition to control mode. Further, if there is no input from the input unit 104, the charging control unit 103 can be prevented from shifting to this control mode.

  Further, for example, the input unit 104 inputs according to the user's instruction to set the charging completion voltage by the user, and based on this, the charging control unit 103 shifts to a control mode in which the charging completion voltage is set according to the user's instruction. . Further, if there is no input from the input unit 104, the charging control unit 103 can be prevented from shifting to this control mode.

Thus, by specifying the control mode desired by the user, the charging control apparatus 100 can operate in the desired control mode. In particular, charging control using a voltage value and a timer, and a control mode capable of changing the charging completion voltage are registered in advance in the charging control device 100 as a battery eco mode, a battery stamina mode, etc. It is possible to prevent overcharging.

Next, the operation of the charging control apparatus 100 described above will be described together.
FIG. 5 is a diagram for explaining an example of the operation of the charging control apparatus 100. In FIG. 5, only a part of the constituent parts of the charging control device 100 is described, and it does not indicate that the constituent parts not shown in FIG. 5 are not included in the charging control device 100. Further, “charge control” in the figure indicates a part of the operation of the charge control unit 103, and does not indicate all the operations of the charge control unit 103. In addition, the charging control unit 103 includes OR circuits 520 and 530 and timers 540 and 550.

  First, when the external power supply detection unit 101 detects application of an external power supply (step S501), the secondary battery voltage detection unit 102 detects a secondary battery voltage. When the external power source detection unit 101 does not detect the application of the external power source (step S502), the process ends.

  The charge control unit 103 determines whether or not the secondary battery voltage is equal to or lower than the charge determination voltage when performing the charge control using the voltage value shown in FIG. 2, and the charge control using the timer shown in FIG. To determine whether or not the secondary battery voltage is less than or equal to the charge restart voltage, and when the secondary battery voltage is less than or equal to the charge determination voltage or less than the charge restart voltage, charging is started, and the OR circuit A first charging signal is sent to 520 (step S503).

  On the other hand, when the charging control based on the voltage value shown in FIG. 2 is performed and the secondary battery voltage is equal to or higher than the charging determination voltage, the process ends (step S504). Further, in the case where the charging control based on the timer shown in FIG. 3 is performed and the secondary battery voltage is equal to or higher than the charging restart voltage, the signal control unit 103 generates a signal for starting time measurement in the T1 period. The timer 540 is sent to the timer 540 (step S505), the timer 540 starts time measurement for the T1 period, and the charge controller 103 sends a signal for starting time measurement for the T2 period to the timer 550 (step S506). Starts time measurement in the T2 period. The timer 550 sends a first light emission signal to the OR circuit 530 from the start of the measurement in the T2 period until the elapse of the T2 period is detected (step S507).

  When the timer 540 detects the elapse of the T1 period, it sends a second charging signal to the OR circuit 520 (step S508). When either the first charging signal or the second charging signal is input, the OR circuit 520 transmits a charging start signal instructing the start of charging (step S509). Based on the charging start signal, the charging control unit 103 starts charging the secondary battery 300 from the external power source 200 via the charging FET 560 and the resistor 570. This charging is continued until the transmission of the charging start signal is completed.

  The charging control unit 103 sends a charging display signal (second light emission signal) to the OR circuit 530 to inform the user that charging is in progress during the period in which the charging start signal is detected (step S510). When either the first light emission signal or the second light emission signal is input, the OR circuit 530 transmits an LED light emission signal instructing the start of light emission of the LED 105 (step S511). The charging control unit 103 emits light from the LED 105 based on the LED light emission signal. This light emission is continued until the LED light emission signal is transmitted.

  Further, in the selection of the charge completion voltage by the user setting, the input unit 104 inputs a desired charge completion voltage (in this case, the charge completion voltage A or the charge completion voltage B) according to a user instruction, and the input unit 104 is charged. A desired voltage signal related to the charging completion voltage input to the control unit 103 is transmitted (step S512). Further, although not shown, the charging completion voltage can be set based on various charging conditions (external charging conditions such as USB charging and non-contact charging).

  According to such a charging control apparatus 100, the external power supply detection unit 101 that detects the external power supply 200 that supplies power to the secondary battery 300, the secondary battery voltage detection unit 102 that detects the voltage of the secondary battery 300, and When the external power source 200 is detected by the external power source detection unit 101 and the voltage of the secondary battery 300 is higher than a predetermined charging determination voltage used when the external power source 200 is detected, With the configuration including the charge control unit 103 that prohibits charging of the battery 300, overcharge of the secondary battery can be regularly prevented and the battery life can be extended.

  INDUSTRIAL APPLICABILITY The present invention is useful for a charge control device, a portable terminal device, and the like that can prevent overcharge of a secondary battery constantly.

The block diagram which shows the structure of the charge control apparatus in embodiment of this invention. The figure for demonstrating the charge control method based on the secondary battery voltage which the charge control part in embodiment of this invention performs The figure for demonstrating the charge control method based on the timer which the charge control part in embodiment of this invention performs (A) Time voltage characteristics depending on each charging completion voltage in the embodiment of the present invention (b) Cycle number capacity characteristics depending on each charging completion voltage The figure for demonstrating an example of operation | movement of the charge control apparatus in embodiment of this invention. Overview of conventional charging system

Explanation of symbols

DESCRIPTION OF SYMBOLS 100 Charge control apparatus 101 External power supply detection part 102 Secondary battery voltage detection part 103 Charge control part 104 Input part 105 LED
106 Communication Unit 200 External Power Supply 300 Secondary Battery 520, 530 OR Circuit 540, 550 Timer 560 Charge FET
570 Resistor 601 External power supply 602 Charging FET
603 Resistor 604 Secondary battery 605 Charge control unit

Claims (7)

An external power supply detection unit for detecting an external power supply for supplying power to the secondary battery;
A secondary battery voltage detector for detecting the voltage of the secondary battery;
When the external power source is detected by the external power source detection unit and the voltage of the secondary battery is higher than a predetermined charge determination voltage used when the external power source is detected, the secondary battery is supplied from the external power source. And a charge control unit that prohibits charging the battery. The charge control device according to claim 1,
When the external power source is detected by the external power source detection unit, the charging control unit causes the presentation unit to present that the external power source has been detected. The charge control device according to claim 1,
The charging control unit may be configured such that when a predetermined time elapses after the external power source is detected by the external power source detecting unit, or a voltage of the secondary battery is lower than a predetermined charging restart voltage lower than the charging determination voltage. A charge control device that charges the secondary battery from the external power source when at least one of the low cases is satisfied. The charge control device according to claim 1,
A charging completion voltage setting unit for setting a charging completion voltage for completing charging of the secondary battery;
The charge control unit is a charge control device that performs charging of the secondary battery until the charge completion voltage is reached. The charge control device according to any one of claims 1 to 4,
A control mode designating unit for designating a control mode indicating which control the charge control unit performs;
The charge control unit is a charge control device that performs control based on the control mode.   The portable terminal device which has a charge control apparatus of any one of Claims 1 thru | or 5. In the charge control device that controls the charging of the secondary battery,
An external power source detection step for detecting an external power source for supplying power to the secondary battery;
Detecting a voltage of the secondary battery;
A step of controlling charging from the external power source to the secondary battery when an external power source is detected in the external power source detection step and the voltage of the secondary battery is higher than a predetermined charging determination voltage; A charge control method.

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