JP2000125477A - Charging circuit, charging method and recording medium thereof - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a charging circuit, a charging method and a recording medium which can suppress the decline in service life of a battery cell or other circuit components of electronic equipment due to overvoltage and improve safety, in a charging operation and the reliability of the electronic equipment. SOLUTION: A supply voltage is compared with a reference voltage by a comparator 121. If the supply voltage is not lower than the reference voltage, a signal of level 'L' is supplied to the gate electrode of a control FET 111, to turn off the control FET 111 and a charging path is cut off. Further, if an overvoltage is applied continuously for a period not less than a predetermined time, a user is informed of the fact that an overvoltage is applied or that charging operation is discontinued through an alarm message, alarm sound, etc., by using a display device 119 or a buzzer 127. Moreover, time information such as the date, time, etc., of that occasion and physical information such as the temperature, an overvoltage value, a supply current value, etc., at that time are recorded in a memory 117.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a charging circuit and a charging method applied to a battery-driven portable electronic device such as a cellular phone and a video camera, and a recording medium storing a program for executing the charging method. In particular, the present invention relates to a charging circuit, a charging method, and a recording medium that suppress a decrease in the life of a battery cell or other circuit components of an electronic device due to an overvoltage, and further improve safety in charging operation and reliability of the electronic device.

[0002]

2. Description of the Related Art Conventionally, in a battery-driven portable electronic device such as a cellular phone or a video camera, the battery cell is charged by applying charging energy supplied from an external charger to the battery cell. Charging circuit for charging. In such a charging circuit, an overcharge protection circuit that prevents overcharging in which a voltage is applied from the outside even after the charging is completely completed, and an overcharge protection circuit that prevents overdischarging in which the battery cell continues to discharge beyond the final voltage. In general, the battery pack has a discharge protection circuit, and further has an overvoltage protection circuit to protect the battery cell when the voltage applied from the external charger to the battery cell is overvoltage. is there.

As the simplest configuration of the overvoltage protection circuit, for example, there is a configuration in which an external charger is connected and a zener diode is reversely connected between a positive electrode terminal and a negative electrode terminal to which a charging voltage is applied. This utilizes the reverse characteristic of a Zener diode, and suppresses the voltage applied to a battery cell to a Zener voltage by Zener breakdown of the Zener diode even when an overvoltage is applied between the positive and negative terminals. It is.

On the other hand, in order to prevent an excessive voltage or current from being output from an output terminal on the external charger side, for example, when a commercial power supply voltage is applied as it is due to a malfunction or a malfunction, the external charging is performed. If an excessive voltage or current is to be output from the output terminal by providing a fuse or the like inside the device, the fuse may be cut to prevent output of excessive voltage or current. Had been

[0005]

Incidentally, portable electronic devices provided with such a charging circuit are generally sold with a dedicated external charger attached to the portable electronic device. Also, when charging the built-in battery cell, it is announced that a dedicated external charger or a charger specified by the manufacturer is used. However, when charging a battery cell of a portable electronic device, a user does not necessarily have a dedicated external charger,
In some cases, an unscheduled external charger may be used that is not expected by the developer.

When an overvoltage is supplied due to such an unexpected use of an external charger or a malfunction of the external charger,
In the charging circuit of the above-described conventional portable electronic device, it is possible to suppress the overvoltage to the Zener voltage by the Zener diode of the overvoltage protection circuit, but a voltage having a Zener voltage level higher than the normal charging voltage is applied to the battery cell. Will be done. Therefore, when charging by the overvoltage cannot be recognized by the user, the Zener voltage is applied to the battery cell for a long time, and as a result, there is a problem that the life of the battery cell is shortened.

Furthermore, electronic components used in portable electronic devices often have low withstand voltage, and the supply of overvoltage or zener voltage is not only required for battery cells but also for charging circuits and portable electronic devices. There is also a problem that even the electronic parts of the circuit part are damaged or the life of the electronic parts is shortened.

SUMMARY OF THE INVENTION The present invention has been made in view of the above circumstances. Even when an overvoltage is supplied due to an unexpected use of an external charger, a malfunction of the external charger, or the like, a battery cell, a charging circuit, or an electronic device may be provided. A charging circuit and charging method that further improves the safety in charging operations and the reliability of electronic devices by eliminating factors that lead to damage to electronic components and shortened component life in other circuit parts of the device And a recording medium.

[0009] Another object of the present invention is to provide a system in which an overvoltage is supplied to a user when an overvoltage is supplied due to an unexpected use of an external charger or a malfunction of the external charger. An object of the present invention is to eliminate the application of the voltage at the Zener voltage level, thereby suppressing a reduction in the life of the battery cell or other circuit components of the electronic device, and further improving the reliability of the battery cell or the electronic device.

Still another object of the present invention is to record a history of time information and physical information of a circuit when an overvoltage is supplied due to an unexpected use of an external charger or a malfunction of the external charger. Accordingly, it is possible to enhance maintenance workability such as troubleshooting in an electronic device.

[0011]

In order to solve the above-mentioned problems, a charging circuit according to a first aspect of the present invention includes a battery cell that is stored by a voltage supplied from an external charger. A charging circuit of an electronic device to be driven, wherein the voltage comparing unit compares a voltage supplied from the external charger with a predetermined reference voltage, and the voltage is equal to or higher than the reference voltage based on a comparison result of the voltage comparing unit. Switching means for controlling the opening of the charging path when charging the battery cell when the overvoltage is exceeded.

The charging circuit according to a second aspect of the present invention is the charging circuit according to the first aspect, further comprising overvoltage suppressing means for suppressing a voltage supplied from the external charger, and wherein the voltage comparing means includes the overvoltage suppressing means. And comparing the obtained voltage with the reference voltage.

According to a third aspect of the present invention, in the charging circuit according to the first or second aspect, the control means controls opening and closing of the charging path by the switching means according to a comparison result of the voltage comparing means. It is characterized by having.

According to a fourth aspect of the present invention, there is provided the charging circuit according to the first, second, or third aspect, further comprising a notification unit configured to notify a user of the electronic device of the application of the overvoltage. .

According to a fifth aspect of the present invention, in the charging circuit according to the fourth aspect, the notifying means is an audio output means for generating a warning sound.

According to a sixth aspect of the present invention, in the charging circuit according to the fourth aspect, the notifying means is a display means for displaying a warning message.

The charging circuit according to claim 7 is the charging circuit according to claim 1, 2, 3, 4, 5, or 6,
A storage unit for storing time information when the overvoltage is applied or physical information in the charging circuit is provided.

The charging circuit according to claim 8 is the charging circuit according to claim 4, 5, 6, or 7, wherein the notification is provided when the overvoltage is continuously applied to the charging circuit for a predetermined time or more. Notification by means or recording by the storage means is performed.

According to a ninth aspect of the present invention, there is provided a method for charging a battery cell in an electronic device having the battery cell stored by a voltage supplied from an external charger.
A voltage comparison step of comparing a voltage supplied from the external charger with a predetermined reference voltage; and opening control of a charging path for charging the battery cell when the voltage is an overvoltage equal to or higher than the reference voltage. And an informing step of informing the user of the electronic device of the application of the overvoltage.

According to a tenth aspect of the present invention, in the charging method of the ninth aspect, the notification in the notification step is performed by generating a warning sound.

[0021] In a charging method according to an eleventh aspect, in the charging method according to the ninth aspect, the notification in the notification step is performed by displaying a warning message.

According to a twelfth aspect of the present invention, there is provided a method for charging a battery cell in an electronic device having a battery cell stored by a voltage supplied from an external charger. A voltage comparison step of comparing the voltage to be applied with a predetermined reference voltage, and when the voltage is an overvoltage equal to or higher than the reference voltage, an open control step of opening and controlling a charging path for charging the battery cell, Storing time information or physical information of the circuit when the overvoltage is applied.

The charging method according to claim 13 is the charging method according to claim 9, 10, 11, or 12,
When the overvoltage is continuously applied for a predetermined time or more,
The notification step or the storage step is performed.

Further, a computer-readable recording medium according to claim 14 is a computer-readable recording medium.
It is stored as a program for causing a computer to execute the charging method described in 1, 12, or 13.

In the charging circuit according to the first, second and third aspects of the present invention, the voltage supplied from the external charger is compared with the reference voltage by the voltage comparing means. Therefore, when this voltage is an overvoltage equal to or higher than the reference voltage, the charging path is opened. In particular, in the charging circuit according to claim 2, the overvoltage suppressing unit suppresses the voltage supplied from the external charger, and compares the suppressed voltage with the reference voltage by the voltage comparing circuit. Further, in the charging circuit according to the third aspect, the control means controls opening and closing of the charging path by the switching means according to the comparison result of the voltage comparing means.

Thus, when an overvoltage is supplied due to an unexpected use of the external charger, a malfunction of the external charger, or the like, the charging path can be immediately cut off to stop the charging, and the overvoltage application state can be stopped. Can be eliminated, and the cause of battery cell life reduction can be eliminated, and the occurrence of malfunctions such as ignition, smoke, rupture or liquid leakage of the battery cell can be suppressed, thus eliminating the cause of the battery cell becoming unusable. it can. In particular, since the overvoltage supplied from the external charger is suppressed by being configured in combination with the overvoltage control means, even if an electronic component having a low withstand voltage is used for the charging circuit or another circuit of the electronic device, the electronic circuit can be used. There is no risk of parts being destroyed by an overvoltage or the charging circuit or the electronic device becoming unusable, and safety in charging operation and reliability of the electronic device can be further improved.

In the charging circuit according to the fourth, fifth and sixth aspects, the charging method according to the ninth, tenth and eleventh aspects, and the recording medium according to the fourteenth aspect, the voltage supplied from the external charger and the reference The voltage is compared with the voltage by voltage comparison means (voltage comparison step). If the voltage is an overvoltage equal to or higher than the reference voltage based on the comparison result of the voltage comparison means (voltage comparison step), the charging path is switched by the switching means (open control step). Is opened, and the notification unit (notification step) notifies the user of the electronic device of the application of the overvoltage. In particular, in the charging circuit according to the fifth aspect and the charging method according to the tenth aspect, a warning sound is generated by the audio output means, and in the charging circuit according to the sixth aspect and the charging method according to the eleventh aspect, the warning means is displayed by the display means. Display a message.

Thus, when an overvoltage is applied due to an unexpected use of the external charger, a malfunction of the external charger, or the like, the user is notified of this and the connection between the electronic device and the external charger is established. It is possible to prompt the user to release the connection immediately or to disconnect the commercial power supply from the external charger. Therefore, the applied state of the overvoltage to the battery cell, the charging circuit, or other electronic components of the electronic device can be eliminated in a shorter time, and the damage and shortening of the life of the battery cell, the charging circuit, or other electronic components of the electronic device can be suppressed. Therefore, the reliability of the battery cell, the charging circuit, or the electronic device can be further improved. The charging method according to the ninth aspect also has the above-described operation and effect in the charging circuit according to the first aspect.

A charging circuit according to claim 7 and claim 1.
In the charging method according to the second aspect and the recording medium according to the fourteenth aspect, the storage unit (storage step) stores time information when an overvoltage is applied to the charging circuit or physical information of the charging circuit. Here, the time information corresponds to, for example, year, month and day, and the date and time, and the physical information of the circuit corresponds to, for example, electrical information such as a temperature, an overvoltage value, and a current value.

Thus, the time when the overvoltage is applied can be known from the stored time information, and the state of the electronic device when the overvoltage is applied can be known from the physical information of the circuit. When the electronic device repairs the electronic device or the like, the cause of the failure can be efficiently investigated, and maintenance workability such as troubleshooting of the electronic device can be improved. Further, if the time information and the physical information of the circuit recorded in the storage means are transmitted as history information to the network management side together with the ID number of the electronic equipment by the transmission means provided in the electronic equipment, The administrator can also grasp the usage history such as whether an overvoltage has been applied to the electronic device under management.

[0031] Further, a charging circuit according to claim 8 and claim 1.
In the charging method according to the third aspect and the recording medium according to the fourteenth aspect, when an overvoltage is continuously applied to the charging circuit for a predetermined time or more, a notification by a notification unit (notification step), for example, a warning sound by an audio output unit. Alternatively, notification by a warning message by the display means or recording by the storage means (storage step) is performed. As described above, the notification and the warning are performed only when the elapsed time of the overvoltage application is equal to or longer than the predetermined time, so that the overvoltage or the like impulsively caused by the rush current or the like when the electronic device is connected to the external charger. And unnecessary notifications, warnings and the like are prevented from being performed. In other words, the user returns to the normal state and resumes charging without notifying the user of the momentarily applied overvoltage, so that the user is notified and warned only when continuous overvoltage is applied. Etc. can be performed.

[0032]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Embodiments of a charging circuit, a charging method and a recording medium according to the present invention will be described below in detail with reference to the drawings. In the description of the embodiment, the charging circuit and the charging method according to the present invention will be described in detail, but the recording medium according to the present invention is a recording medium that records a program for executing the charging method.
The description is included in the following description of the charging method.

The charging circuit of the present embodiment is intended for charging a battery cell such as a nickel cadmium storage battery, a nickel metal hydride storage battery, or a lithium ion secondary battery, and includes an electronic notebook, a mobile phone, a liquid crystal television, a video camera, and a notebook computer. It is used in various battery-powered portable electronic devices.

FIG. 1 is a circuit diagram showing a charging circuit according to one embodiment of the present invention. In the figure, the charging circuit of this embodiment forms a part of a portable electronic device, and includes a positive terminal 101, a negative terminal 103, a battery cell 105, a Zener diode 109, an overcharge protection circuit 107, a control field effect transistor. (Hereinafter referred to as control FET) 11
1, a charge control circuit 113, a regulator 123, a comparator 121, a microcomputer (hereinafter, referred to as a microcomputer) 115, a display element 119, a drive circuit 125, a buzzer 127, and a memory 117. In addition, the charging circuit includes, in addition to the above components, a thermistor that detects whether or not charging is performed within a predetermined temperature range and controls charging, a charging temperature detection circuit, an overdischarge protection circuit, and the like. However, since it is not directly related to the present invention, the description of the configuration and operation is omitted.

Battery cell (unit cell) 105
Is a unit battery configured to include a negative electrode, a positive electrode, an electrolyte, a current collector, and the like as its structure. In the case of a lithium-ion battery, since it is not strong against extreme overcharging, the internal structure of the
It has an element, a safety valve, a low melting point separator and the like. For example, in the case of having a cylindrical battery structure, the PTC element is made of a resin containing conductive carbon, and when a large current flows and the temperature rises, the resin expands and cuts the path of the conductive carbon. Cut off the current. The safety valve is made of a metal thin film or the like, and is a component that is destroyed when the internal pressure of the voltage is increased due to vaporization of the electrolyte or decomposition gas when the temperature rises, thereby preventing the battery from being destroyed. Further, the separator uses porous polyethylene, polypropylene or a composite film thereof. If a large current flows due to an external short circuit or the like and the battery temperature rises above the melting point of the separator, clogging occurs and the current is cut off.

The Zener diode 109 corresponds to the overvoltage suppressing means described in the claims, and the positive terminal 1
01 and the negative terminal 103 are connected in reverse. When an excessive supply voltage (overvoltage) is supplied from an external charger, the Zener diode 109 suppresses a voltage applied to the battery cell to a Zener voltage due to a Zener breakdown having a reverse characteristic of the Zener diode 109. .
This can prevent an overvoltage from being applied to the battery cell, the charging circuit, and electronic components of other circuit parts of the portable electronic device. However, a voltage having a Zener voltage level higher than a normal charging voltage can be reduced. Since the voltage is applied to parts and the like, it is necessary to reduce the time during which the Zener voltage is applied by the operation of the components described below in order to further reduce the effect.

The overcharge protection circuit 117 includes, for example, a current detecting means and a field effect transistor (hereinafter referred to as an FET).
And the like, and the battery cell 10 is charged from the overcharge where the voltage is externally applied even after the charging is completed.
5 to protect the battery cell 105 by the current detecting means.
The charging current supplied to the battery cell 105 is detected, and when the charging current becomes equal to or lower than the level corresponding to the termination of charging, the path of the charging current supplied to the battery cell 105 is cut off using the FET. For example, in the overcharge protection circuit 117 in which the charging end current is set to 70 mA, when the charging current supplied to the battery cell 105 is detected to be 70 mA or less, the control signal supplied to the gate electrode of the FET is set to “L”. The potential is set to the level, the FET is turned off, the charging path is cut off, and charging is stopped.

The charging control circuit 113 obtains physical (electrical) information in the charging circuit and supplies the information to the microcomputer 115. In particular,
The supply voltage and the supply current supplied from the external charger are detected, and the supply voltage value and the supply current value (digital value) are detected.
Is supplied to the microcomputer 115.

The regulator 123 is connected to the battery cell 1
The comparator 1 generates a predetermined constant voltage based on the voltage of the comparator 05 as a reference voltage (Vref) for detecting an overvoltage.
21. Note that the regulator 123 may be a regulator used in another circuit in the portable electronic device, and does not need to be newly configured for the charging circuit of the present embodiment.

The comparator 121 corresponds to a voltage comparing means, and supplies a supply voltage (Vad) supplied from an external charger.
d) is compared with the reference voltage (Vref) output from the regulator 123, and when the supply voltage (Vadd) is lower than the reference voltage (Vref), a signal having an “H” level potential is output; When the supply voltage (Vadd) is equal to or higher than the reference voltage (Vref), it is determined that an overvoltage has been detected, and a signal having an “L” level potential is output. The output signal (OVR) of the comparator 121 is supplied to the gate electrode of the control FET 111 as a control signal, and is also supplied to the microcomputer 115 as an interrupt signal. Note that a difference value between the reference voltage (Vref) and the supply voltage (Vadd) may be obtained by using an OP amplifier instead of the comparator 121 and may be used as an output signal (OVR).

The control FET 111 corresponds to a switching means, is inserted into a path (charging path) of a charging current flowing from the external charger to the battery cell 105, and responds to an output signal (OVR) as a comparison result of the comparator 121. The charging path is opened and closed by switching control of on / off operation.
That is, when overvoltage is detected by the comparator 121, the charging path is turned off to control the opening of the charging path, and otherwise, the charging path is maintained by the on operation. For example, in the case of an overvoltage due to an inrush current or the like, the control FET 111 is turned off instantaneously, but in many cases, the overvoltage due to the inrush current is impulsively applied. Will be performed. In the present embodiment, an n-channel MOSFET for power is used for the control FET 111, but another semiconductor switching element such as a bipolar transistor may be used instead. However, it is desirable to use a power element also in a bipolar transistor or the like.

The microcomputer 115 corresponds to a control means, uses the output signal (OVR) of the comparator 121 as an interrupt signal, and executes an interrupt process when the supply voltage (Vadd) is an overvoltage. That is, the output signal (OVR) of the comparator 121 is input to the external interrupt terminal of the microcomputer 115 as an interrupt signal, and when the interrupt signal (OVR) is valid (“L” level), the external interrupt is issued to the microcomputer 115. It takes.
In the interruption process of the microcomputer 115 by the external interruption, first, in order to eliminate the case where the impulsive overvoltage is applied, it is determined whether or not the overvoltage is continuously supplied for a certain period of time by a software timer or the like. The valid (“L” level) time is counted and determined. When the elapsed time exceeds a predetermined time, for example, 100 milliseconds, the microcomputer 115 determines that continuous application of the overvoltage has occurred, displays a warning message by the display element 119, generates a warning sound by the buzzer 127, and The memory 117 stores time information, physical (electrical) information, and the like.

The display element 119 corresponds to display means for notifying the user of the application of the overvoltage by displaying a warning message, and is realized by a liquid crystal display or the like. As the warning message displayed on the display element 119, a fixed phrase such as "excessive voltage has been applied" or "charging has stopped" may be displayed. In addition, a predetermined display area of the display element 119 may be set to a specific color, a displayed warning message may be highlighted, or the warning message may be displayed in an enlarged character to draw the user's attention by highlighting. good. Furthermore, as a warning message, in addition to displaying a fixed phrase, it is also conceivable that a mark or symbol such as a specific icon is graphically displayed to give a warning.

The buzzer 127 corresponds to audio output means for notifying the user of the application of an overvoltage by generating a warning sound, and the microcomputer 115 outputs a drive signal (DRV) from the microcomputer 115 to the drive circuit 125 by interrupt processing. When output, a warning sound such as a beep sound is generated by the drive of the drive circuit 125. Instead of the warning sound by the buzzer 127, a fixed message such as "excessive voltage has been applied" or "charging has stopped" may be issued by voice via a speaker. However, in this case,
A means for voice synthesizing these fixed messages is required inside the portable electronic device.

Further, the memory 117 corresponds to a storage means for storing time information when an overvoltage is applied and physical (electrical) information in the charging circuit, and is realized by a nonvolatile flash memory, an EEPROM, or the like. You. The recording process of the time information and the physical information is executed as an interrupt process of the microcomputer 115. That is, the date and time when a continuous overvoltage is applied are used as time information, the temperature measured by a thermopile or the like (not shown), the supply voltage value obtained by the charge control circuit 113,
The supply current value and the like are recorded in the memory 117 as physical information.

Next, an external charger (an external charger that does not conform to the specification of the battery cell) having a different specification such as an output capacity from a dedicated external charger attached to a portable electronic device provided with the charging circuit of the present embodiment, An external charger that is not specified by the manufacturer, particularly an external charger that supplies a higher voltage (overvoltage) than the charging voltage specified in the battery cell 105 or the portable electronic device (hereinafter, referred to as an external charger). The operation of the charging circuit of the present embodiment having the above-described configuration will be described with reference to the flowchart of FIG. 2, focusing on the case where an external charger that is not dedicated is used. FIG. 2 is a flowchart illustrating a charging process with overvoltage protection in the charging circuit of the present embodiment.

When an overvoltage is applied from a non-dedicated external charger, the overvoltage is suppressed to a zener voltage by a zener diode 109 reversely connected between the positive terminal 101 and the negative terminal 103. This can prevent an overvoltage from being applied to the battery cell, the charging circuit, and electronic components of other circuit parts of the portable electronic device. However, a voltage having a Zener voltage level higher than a normal charging voltage can be reduced. Since the voltage is applied to the components and the like, the time during which the Zener voltage is applied to the battery cells and the electronic components is reduced by the following processing in order to further reduce the influence on the battery cells and the electronic components.

First, in step S201, the comparator 121 supplies the supply voltage (V) supplied from the external charger.
add) and a reference voltage (Vref) supplied from the regulator 123. Next, in step S203, as a result of the comparison by the comparator 121, it is determined whether the supply voltage (Vadd) is equal to or higher than the reference voltage (Vref). The supply voltage (Vadd) is equal to the reference voltage (Vr).
ef), the process proceeds to step S205,
Normal charging processing is performed. That is, the comparator 1
21 is at "H" level and the control FE
Since T111 is an ON operation, the charging path is maintained and the battery cell 105 is normally charged. Note that the processing of steps S201 to S205 and the processing of step S206 are realized by hardware processing of the charging circuit, and steps S207 to S21 described below are performed.
The process of No. 5 is performed by an interrupt process according to an interrupt program of the microcomputer 115.

On the other hand, if the supply voltage (Vadd) is an overvoltage equal to or higher than the reference voltage (Vref) in step S203, the process proceeds to step S206 to stop charging. That is, the output signal (O
VR) is at the “L” level, and the control FET 111 is turned off, so that the charging path is cut off and charging of the battery cell 105 is stopped. At this time, the comparator 121
Output signal (OVR) is used as an interrupt signal by the microcomputer 1
15, the microcomputer 115 starts the interrupt processing after step S207.

First, in steps S207 to S210,
The time during which the interrupt signal (OVR) is valid ("L" level) is counted by a software timer or the like, and it is determined whether or not the overvoltage is continuously supplied for a predetermined time or more.
This means that if an impulse-like overvoltage is applied,
This is because the interruption and restoration of the charging path are only performed instantaneously and continuously by the off / on operation of the control FET 111, and the processing of the following steps S211 to S215 is not performed. That is, when the timer counts a predetermined time (for example, 100 milliseconds), the interrupt signal (OV
When R) is valid (“L” level), the microcomputer 11
No. 5 judges that continuous overvoltage application has occurred, and proceeds to steps S211 to S215.

In step S211, a warning message is displayed on the display element 119 connected to the microcomputer 115. In step S213, a warning sound is generated using the buzzer 127. Further, in step S215, the microcomputer 115 outputs time information such as date, date and time,
In addition, physical information such as a temperature, a supply voltage value, and a supply current value is recorded in the memory 117. In FIG. 2, for simplicity, steps S <b> 211 to S <b> 215 are described as being processed in parallel, but these three processes may be performed substantially simultaneously and continuously (in any order). There is no need to be.

As described above, the charging circuit of this embodiment includes the comparator 121 and the control FET 111, and compares the supply voltage supplied from the external charger with the reference voltage supplied from the regulator 123 by the comparator 121. When the supply voltage is equal to or higher than the reference voltage, an "L" level signal is supplied to the gate electrode of the control FET 111 to turn off the control FET 111 and cut off the charging path. Accordingly, when an overvoltage is supplied due to an unexpected use of an external charger, a malfunction of the external charger, or the like, the charging path can be immediately cut off to stop charging, and the overvoltage application state can be eliminated. Therefore, it is possible to eliminate the cause of the shortening of the life of the battery cell 105 and to suppress the occurrence of troubles such as ignition, smoking, rupture or liquid leakage of the battery cell 105, thereby eliminating the cause of the battery cell 105 becoming unusable. it can.

Furthermore, the provision of the Zener diode 109 suppresses the voltage supplied from the external charger, so that the charging circuit or other circuits of the portable electronic device are driven at a low voltage, especially with a low withstand voltage. Even if components are used, there is no risk that these electronic components will be destroyed by overvoltage or that the charging circuit or the portable electronic device will not be usable, thereby further improving the safety in charging operation and the reliability of the portable electronic device. It becomes possible.

Further, the charging circuit of this embodiment includes the display element 119 and the buzzer 127, and when an overvoltage is continuously applied for a predetermined time or more, a warning message or a warning sound indicates that the overvoltage has been applied. Alternatively, the user is notified using the display element 119 or the buzzer 127 that the charging has been stopped. Accordingly, when an overvoltage is applied for a predetermined time or more due to an unexpected use of the external charger or a malfunction of the external charger, the user is notified that the overvoltage is applied, and the external charger of the portable electronic device is used. Can prompt the user to disconnect from the power supply immediately or disconnect the external charger from the commercial power supply, so that the load on the battery cell 105, the charging circuit, or the portable electronic device can be reduced. The applied state can be eliminated. At the same time, the life of the battery cell 105, the charging circuit, or other electronic components of the portable electronic device can be suppressed from being shortened, and the reliability of the battery cell 105, the charging circuit, or the portable electronic device can be further improved.

Further, when a predetermined time has passed since the application of the overvoltage, a notice or a warning is given for the first time, so that an impulse current such as an inrush current when the portable electronic device is connected to an external charger is obtained. , So that no warning is issued. In other words, for an overvoltage applied instantaneously, the user is returned to a normal state and restarted charging without giving unnecessary notice, warning, etc. to the user. The user can be notified, warned, etc. only at

Further, the charging circuit of the present embodiment includes a memory 117, and when an overvoltage is applied to the charging circuit for a predetermined time or more, the microcomputer 115 outputs time information such as date, date and time, and temperature. , Physical information such as an overvoltage value and a supply current value. Thus, the time when the overvoltage is applied can be known from the time information stored in the memory 117, and the state of the portable electronic device when the overvoltage is applied can be known from the physical information of the circuit. When the manufacturer of the portable electronic device repairs the portable electronic device or the like, the cause of the failure can be efficiently investigated, and maintenance workability such as troubleshooting of the portable electronic device can be improved.

The time information and the physical information of the circuit recorded in the memory 117 are transmitted as history information to the network management side together with the ID number of the electronic device and the like by transmitting means provided in the portable electronic device. By doing so, the system administrator of the network can also grasp the usage history such as when and what overvoltage is applied to the portable electronic device under management.

[0058]

As described above, according to the charging circuit of the present invention, the voltage supplied from the external charger is compared with the reference voltage by the voltage comparing means. Therefore, when this voltage is an overvoltage equal to or higher than the reference voltage, the charging path is controlled to be opened, so that if an overvoltage is supplied due to an unexpected use of an external charger or a malfunction of the external charger, the charging path is immediately started. To stop charging and eliminate the over-voltage application state, eliminating the cause of battery cell life reduction, and preventing malfunctions such as battery cell ignition, smoke, rupture or liquid leakage. Since the occurrence is suppressed, it is possible to provide a charging circuit capable of eliminating a factor that makes the battery cell unusable. In particular, if the overvoltage supplied from the external charger is suppressed by the overvoltage control means, even if an electronic component having a low withstand voltage is used for the charging circuit or another circuit of the electronic device, the electronic component is destroyed by the overvoltage, There is no possibility that the charging circuit or the electronic device becomes unusable, and the safety in the charging operation and the reliability of the electronic device can be further improved.

According to the charging circuit, the charging method and the recording medium of the present invention, the voltage supplied from the external charger is compared with the reference voltage by the voltage comparing means (voltage comparing step). From the comparison result of the comparison step), when this voltage is an overvoltage equal to or higher than the reference voltage,
The switching means (opening control step) controls the opening of the charging path, and the notifying means (notifying step) notifies the user of the electronic device of the application of the overvoltage. If an overvoltage is applied due to a malfunction of the charger or the like, the user is notified that the overvoltage is applied, and the connection between the electronic device and the external charger is immediately released, or the connection of the commercial power supply to the external charger is released. In such a manner, the state of application of overvoltage to the battery cell, the charging circuit, or other electronic components of the electronic device can be eliminated in a shorter time, so that the battery cell, the charging circuit, or other electronic components of the electronic device can be eliminated. It is possible to provide a charging circuit, a charging method, and a recording medium that can suppress breakage of components and decrease in life and can further improve the reliability of a battery cell, a charging circuit, or an electronic device.

According to the charging circuit, the charging method and the recording medium of the present invention, the storage means (storage step)
Since the time information when the overvoltage is applied to the charging circuit or the physical information of the charging circuit is stored, when the electronic device manufacturer repairs the electronic device, the cause of the failure is efficiently investigated. It is possible to provide a charging circuit, a charging method, and a recording medium that can improve maintenance workability such as troubleshooting in an electronic device.

[Brief description of the drawings]

FIG. 1 is a circuit configuration diagram showing a charging circuit according to an embodiment of the present invention.

FIG. 2 is a flowchart illustrating a charging process with overvoltage protection in the charging circuit of the embodiment.

[Explanation of symbols]

 101 Positive terminal 103 Negative terminal 105 Battery cell 107 Overcharge protection circuit 109 Zener diode (overvoltage suppression means) 111 Control FET (switching means) 113 Charge control circuit 115 Microcomputer (control means) 117 Memory 119 Display element (notification means; display) Means) 121 Comparator (Voltage Comparison Means) 123 Regulator 125 Drive 127 Buzzer (Notification Means; Audio Output Means)

Continued on the front page F term (reference) 5G003 AA01 BA01 CA14 CC02 EA08 FA04 5H030 AA03 AA06 AS11 BB01 FF43 FF52

Claims (14)

[Claims] 1. A charging circuit for an electronic device driven by a battery cell, wherein the battery cell is charged by a voltage supplied from an external charger. A voltage comparing unit that compares a reference voltage, and a switching unit that opens and controls a charging path for charging the battery cell when the voltage is an overvoltage equal to or higher than the reference voltage based on a comparison result of the voltage comparing unit. , A charging circuit comprising: 2. An overvoltage suppression unit for suppressing a voltage supplied from the external charger, wherein the voltage comparison unit compares the suppressed voltage with the reference voltage. 2. The charging circuit according to 1. 3. According to a comparison result of the voltage comparison means,
3. The charging circuit according to claim 1, further comprising control means for controlling opening and closing of the charging path by the switching means. 4. The charging circuit according to claim 1, further comprising a notification unit configured to notify a user of the electronic device of the application of the overvoltage. 5. The charging circuit according to claim 4, wherein said notifying means is an audio output means for generating a warning sound. 6. The charging circuit according to claim 4, wherein said notification means is a display means for displaying a warning message. 7. A storage device for storing time information when the overvoltage is applied or physical information in the charging circuit.
7. The charging circuit according to 5 or 6. 8. The method according to claim 4, wherein when the overvoltage is continuously applied to the charging circuit for a predetermined time or more, the notification by the notification unit or the recording by the storage unit is performed. Or the charging circuit according to 7. 9. A method of charging a battery cell in an electronic device including a battery cell stored by a voltage supplied from an external charger, comprising: a voltage supplied from the external charger; a predetermined reference voltage; A voltage comparison step of comparing, when the voltage is an overvoltage equal to or higher than the reference voltage, an open control step of opening and controlling a charging path for charging the battery cell, and applying the overvoltage to the electronic device. A notification step of notifying a user. 10. The charging method according to claim 9, wherein the notification in the notification step is performed by generating a warning sound. 11. The notification of the notification step is performed by displaying a warning message.
The charging method described. 12. A method of charging a battery cell in an electronic device having a battery cell charged by a voltage supplied from an external charger, comprising: a voltage supplied from the external charger; a predetermined reference voltage; A voltage comparison step of comparing, when the voltage is an overvoltage equal to or higher than the reference voltage, an open control step of opening and controlling a charging path for charging the battery cell; and a time when the overvoltage is applied. A storage step of storing information or physical information of a circuit. 13. The notifying step or the storing step is performed when the overvoltage is continuously applied for a predetermined time or longer.
Or the charging method according to 12. 14. The method of claim 9, 10, 11, 12, or 1.
A computer-readable recording medium stored as a program for causing a computer to execute the charging method according to 3.