JP2003164070A - Battery charger - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a battery charger which can simultaneously charge a battery pack installed in an electrical apparatus and a spare battery pack which is not installed in the electrical apparatus, while considering inexpensive battery packs without a built-in charging circuit. <P>SOLUTION: A battery charger 1 has a first feed terminal 12 to charge a battery pack 4a installed in a cellular phone 3, a second feed terminal 13 to charge a single spare battery pack 4b, and a charging circuit 14 to control charging of the spare battery pack 4b. Based on an input voltage Vcc to the charging circuit 14, charging operation of the spare battery pack 4b is controlled by turning on and off. <P>COPYRIGHT: (C)2003,JPO

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a charger for charging a battery pack containing secondary battery cells, and more particularly to a battery pack mounted on an electric device and a spare battery not mounted on the electric device. The present invention relates to a charger that simultaneously charges a pack.

[0002]

2. Description of the Related Art FIG. 7 is a schematic diagram showing an example of a conventional charger and peripheral equipment. The charger 1'of this figure (a) is
The battery pack 4a 'attached to the electric device 3'is charged and has a function as a stand for holding the electric device 3'being charged. The charger 1'includes a power receiving connector 11 that receives power supply from the AC adapter 2 ', and a power feeding terminal 12 that feeds power to the electric device 3', and the power receiving connector 11 and the power feeding terminal 12 are connected to each other. , Connected by internal wiring.

The AC adapter 2'is a power supply device for supplying power to the charger 1 ', and has an AC commercial power supply as an input.
A C plug 21, a power supply circuit 22 for converting the commercial power supply into a predetermined DC power supply and a constant current / constant voltage circuit 23, a power supply connector 24 connected to the power receiving connector 11 and supplying DC power to the charger 1 ′, Comprising.

The electric equipment 3'includes a power receiving terminal 31 connected to the power feeding terminal 12 and receiving power supply from the charger 1 ',
Charging circuit 32 for controlling the charging operation of the battery pack 4a '
And. The charging circuit 32 includes a diode 321 for preventing backflow and a transistor 322 for controlling charging voltage.
And an internal circuit 323 for controlling the base current of the transistor 322 according to the charge state of the battery pack 4a '.

Using the charger 1'having the above structure,
It is possible to charge the battery pack 4a 'attached to the electric device 3'without removing it from the electric device 3'. Therefore, if the spare battery pack 4b '(this drawing (b)) replaceable with the battery pack 4a' is not owned, only the charger 1'is sufficient as the charging means.

On the other hand, when the spare battery pack 4b 'other than the battery pack 4a' is owned, the spare battery pack 4b '
In order to charge the battery, a charger 5 ′ (this figure (b)) capable of charging the spare battery pack 4b ′ by itself is separately used, or the spare battery pack is attached to the electric device 3 ′ and then the charger 1 ′. Had to use. Especially, when the spare battery pack 4b 'is charged while the electric device 3'is in use,
Battery pack 4a 'and spare battery pack 4b' mounted on the
When charging a single body at the same time, not only the charger 1 ′ but also the charger 5 ′ was essential.

The charger 5'in this figure (b) is an electric device 3 '.
A spare battery pack 4b 'not attached to the battery pack is charged by itself, an AC plug 51 that receives an AC commercial power supply as an input, a power supply circuit 52 that converts the commercial power supply into a predetermined DC power supply, and a constant current constant voltage Circuit 53 and spare battery pack 4
It comprises a charging circuit 54 for controlling the charging operation of b ′ and a power supply terminal 55 for supplying power to the spare battery pack 4b ′. The charging circuit 54 has the same configuration as the charging circuit 32 described above, and includes a diode 541 for preventing backflow, a transistor 542 for controlling a charging voltage, and a base current of the transistor 542 depending on the charging state of the spare battery pack 4b ′. And an internal circuit 543 for controlling the.

If the charger 5'having the above structure is used,
It is possible to charge the spare battery pack 4b 'by itself without mounting it on the electric device 3'. Therefore,
The spare battery pack 4b 'can be charged alone while the electric device 3'is in use or the battery pack 4a' is being charged.

The battery pack 4a 'and the spare battery pack 4b' described above do not have a built-in charging circuit for controlling the charging operation, and the secondary battery cells 41a, 41b and a safety circuit for preventing overcharging or overdischarging. This is a type of battery pack that only contains (not shown). Further, the battery pack 4a 'and the spare battery pack 4b' have a structure that can be easily attached to and detached from the electric device 3'and the charger 5 '.

[0010]

Certainly, if both the chargers 1'and 5'having the above-mentioned configuration are owned, the chargers 1'and 5'are properly used depending on the object to be charged, or the battery pack 4a is used. It is easy to use because both'and the spare battery pack 4b 'can be charged at the same time. However, owning both the chargers 1 ′ and 5 ′ not only imposes a cost burden on the user, but also is extremely disadvantageous from the viewpoint of portability.

If the chargers 1'and 5'are simply combined by, for example, incorporating the charging circuit 54 and the feeder terminal 55 of the charger 5'in parallel with the feeder terminal 12 of the charger 1 ', the battery is It is possible to realize a single charger capable of charging both the pack 4a 'and the spare battery pack 4b'. However,
In the charger having such a configuration, the battery pack 4a '
When simultaneously charging the battery pack and the spare battery pack 4b ', the AC adapter 2'exceeds the power supply capacity and causes an abnormal output fluctuation.
Since the charging circuits 32 and 54 may malfunction, it cannot be said that the configuration is realistic.

Further, as shown in FIG. 8, the charging circuit 42
a, 42b built-in type battery pack 4a ", 4
If "b" is adopted as the charging target, the battery pack 4a "and the spare battery pack 4 are provided by the charger 1" that simply branches the power source input to the power receiving connector 11 to the power supply terminals 12 and 13.
It is possible to charge both b ". However, the battery packs 4a", 4b having the charging circuits 42a, 42b built-in.
b "is a battery pack 4 that does not include the aforementioned charging circuit.
Since it is more expensive than a ′ and 4b ′, there is a problem that the running cost of the battery pack, which is a consumable item, is high.

In view of the above problems, the present invention aims to charge an inexpensive battery pack which does not have a built-in charging circuit, but which is mounted on an electric device and a spare battery pack which is not mounted on the electric device. It is an object of the present invention to provide a charger capable of simultaneous charging.

[0014]

In order to achieve the above object, a charger according to the present invention is a first power supply terminal for charging a secondary battery having no charge control function in an electric device. And a second power feeding terminal for charging the secondary battery in a state where the secondary battery is not attached to the electric device, and a charging circuit for controlling charging of the secondary battery connected to the second power feeding terminal. , The second voltage based on the input voltage to the charging circuit
The charging operation of the secondary battery connected to the power supply terminal is turned on / off.

In the charger having the above structure,
The charging circuit has a protection circuit that turns on the charging operation of the secondary battery connected to the second power supply terminal when the input voltage to the charging circuit exceeds a first threshold value, and turns off the charging operation when the input voltage falls below the second threshold value. It is recommended that the configuration be configured as follows.

In the charger having the above structure,
The charging circuit has means for maintaining the charging current to the secondary battery connected to the second power supply terminal at a rated output current or less of a power supply device for supplying power to the charging circuit. Good to do.

[0017]

1 is a schematic configuration diagram showing an embodiment of a charger and peripheral equipment according to the present invention, and FIG. 2 is a schematic vertical sectional view of the charger and peripheral equipment according to the present invention. The charger 1 of the present embodiment is capable of charging both the battery pack 4a attached to the mobile phone 3 and the spare battery pack 4b not attached to the mobile phone 3, and the mobile phone 3 being charged and the spare battery pack 4b. It has a function as a stand for holding the battery pack 4b.

The charger 1 has a power receiving connector 11 for receiving power from the AC adapter 2, a first power feeding terminal 12 for feeding power to the mobile phone 3, and a second power feeding terminal for feeding power to the spare battery pack 4b. 13 and a charging circuit 14 that controls the charging operation of the spare battery pack 4b. Output voltage V of the AC adapter 2 input to the power receiving connector 11
cc is directly supplied to the first charging terminal 12,
It is also supplied to the second charging terminal 13 via the charging circuit 14. The power receiving connector 11 and the first and second power feeding terminals 1
2, 13 and the charging circuit 14 are all connected to the circuit board 15.

The charger 1 of this embodiment has a first recess 16 in which the mobile phone 3 is mounted, a first locking claw 17 for fixing the mobile phone 3, and a second battery pack 4b in which the spare battery pack 4b is mounted. The second recess 18 has a structure having a recess 18 and a second lock claw 19 for fixing the spare battery pack 4b.
Is formed by digging the bottom of the first recess 16 by the thickness of the spare battery pack 4b. In this way, the first and second
If the recesses 16 and 18 have a two-stage structure, the mobile phone 3 and the spare battery pack 4b can be mounted at the same time without increasing the size of the charger 1, so that the portability of the charger 1 can be improved. .

On the other hand, the charging circuit 14, which is a characteristic part of the charger 1 according to the present invention, includes the transistor 1 for controlling the charging voltage.
41, a backflow prevention diode 142, and a charging circuit 1
Resistor 143 for detecting the output current of 4 (charging current to the spare battery pack 4b), a constant current charge control circuit 144 for controlling the base current of the transistor 141 so as to maintain the output current at a predetermined value, and an AC adapter. 2 output voltage Vc
and a protection circuit 145 for controlling on / off of the charging operation of the spare battery pack 4b according to c.

By having the charging circuit 14 having the above-mentioned configuration, the battery pack 4a is included in the charger 1 of the present embodiment.
In addition to the single charging of the spare battery pack 4b, the battery pack 4a and the spare battery pack 4b can be simultaneously charged. The battery pack 4a and the spare battery pack 4b
The charging operation of 1 and the operations of the constant current charging control circuit 144 and the protection circuit 145 which form the charging circuit 14 will be described in detail later.

Next, the AC adapter 2 will be described.
The AC adapter 2 is a power supply device that supplies power to the charger 1, and includes an AC plug 21 that receives an AC commercial power supply as an input,
A power supply circuit 22 and a constant current / constant voltage circuit 23 that convert the commercial power supply into a predetermined DC power supply, and a power supply connector 24 that is connected to the power receiving connector 11 and supplies DC power to the charger 1.
And.

The constant current / constant voltage circuit 23 includes a battery pack 4a.
And an output characteristic adapted to the charging characteristic of the spare battery pack 4b. FIG. 3 is a diagram showing the output characteristics of the AC adapter 2, in which the vertical axis represents the output voltage Vcc of the AC adapter 2 and the horizontal axis represents the output current Ibat of the AC adapter 2. In the figure, V1 is the rated output voltage of the AC adapter 2, V2 is the constant voltage control start voltage of the AC adapter 2, I1 is the maximum output current of the AC adapter 2, and I2 is A.
The rated output current of the C adapter 2 and I3 are constant current set values preset in the charging circuit 14, respectively.

As shown in the figure, the output voltage Vcc of the AC adapter 2 is controlled by the constant current / constant voltage circuit 23 to be either a constant current or a constant voltage according to the output current Ibat of the AC adapter 2. . That is, AC adapter 2
The output characteristics of can be divided into a constant current charging area X and a constant voltage charging area Y.

The constant current charging area X is AC
The output current Ibat of the adapter 2 is a region where the output current Ibat is maintained near the maximum output current I1 that exceeds the rated output current I2 regardless of the increase in the output voltage Vcc. The constant voltage charging region Y is the charging circuit 14 , 32 limits the current,
After the output current Ibat becomes close to or below the rated output current I2, the output voltage Vcc of the AC adapter 2 becomes equal to the output current I2.
It is a region where the rated output voltage V1 is maintained regardless of the decrease of bat. In addition, arrows a and b in the figure
Shows a charge control flow of each of the battery packs 4a and 4b over time. These charge control flows will be individually described later in detail.

Next, the mobile phone 3 will be described. The mobile phone 3 includes a power receiving terminal 31 that is connected to the power feeding terminal 12 and receives power supply from the charger 1, and a charging circuit 32 that controls the charging operation of the battery pack 4a. The charging circuit 32 includes a diode 321 for preventing backflow, a transistor 322 for controlling the charging voltage, and an internal circuit 323 for controlling the base current of the transistor 322 according to the charging state of the battery pack 4a.

The mobile phone 3 having the above-mentioned configuration is used as the charger 1.
When mounted in the first recess 16 formed in the mobile phone 3,
Is fixed to the first recess 16 by the first lock claw 17,
The 1st electric power feeding terminal 12 and the electric power receiving terminal 31 will be in the state electrically conducted. Therefore, when the AC adapter 2 is connected to the charger 1, the output voltage Vcc of the AC adapter 2 is supplied to the charging circuit 32 via the charger 1, and the charging circuit 32 charges the battery pack 4a.

Next, the battery pack 4a and the spare battery pack 4b will be described. The battery pack 4a and the spare battery pack 4b do not have a built-in charging circuit for controlling the charging operation,
This is a battery pack of a type that includes only the secondary battery cells 41a and 41b and a safety circuit (not shown) that prevents overcharge and overdischarge. The battery pack 4a and the spare battery pack 4b have a structure that can be easily attached to and detached from the charger 1 and the mobile phone 3.

When the spare battery pack 4b having the above structure is mounted in the second recess 18 formed in the charger 1, the spare battery pack 4b is attached to the second recess 18 by the second lock claw 19.
The second power supply terminal 13 and the secondary battery cell 41b are electrically connected to each other. Therefore, when the AC adapter 2 is connected to the charger 1, the charging circuit 14 charges the battery pack 4b.

Next, the charging circuit 14, which is a characteristic part of the charger 1 according to the present invention, will be described in more detail.

First, the constant current charging control circuit 144 which constitutes the charging circuit 14 will be described. The constant current charging control circuit 144 is a circuit that controls charging of the spare battery pack 4b together with the transistor 141, the diode 142, and the resistor 143. The constant current charging control circuit 144 includes various charging functions according to a predetermined charging sequence (installation detection of the spare battery pack 4b, charging start, charge abnormality detection, charge timer, temperature detection, full charge detection, recharge, supplementary charge). , Full charge, charge current setting, charge on / off, etc.), and a general-purpose charge control IC capable of appropriately controlling the charge of the spare battery pack 4b may be used.

Further, the constant current charging control circuit 1 of the present embodiment
As described above, 44 has a function of setting the charging current Ibat2 to the spare battery pack 4b to a constant value. In the present embodiment, the constant current setting value I3 of the charging current Ibat2 is set.
Is set to the rated output current I2 of the AC adapter 2 or less.

By performing such constant current setting,
When charging the spare battery pack 4b, the output voltage Vcc of the AC adapter 2 is always driven in the constant voltage charging region Y (see FIG. 3). For example, when the battery pack 4a and the spare battery pack 4b mounted on the mobile phone 3 are simultaneously charged, even if the load on the mobile phone 3 side fluctuates and the output current Ibat of the AC adapter 2 increases, the maximum output current If it is within the range of I1, the AC adapter 2 can absorb it. Thus, the charger 1 of this embodiment
Since the output voltage Vcc hardly fluctuates even if the load fluctuates on the mobile phone 3 side, the protection circuit 14 described later
The malfunction of 5 is also unlikely to occur, and the charging operation of the spare battery pack 4b can be stably continued without interruption.

Next, the protection circuit 1 constituting the charging circuit 14
45 will be described. Normally, the AC adapter 2 has only a charging capacity for one battery pack in order to reduce the circuit scale. Therefore, both of the battery packs 4a are in an empty charge state.
When the charging of the battery pack and the spare battery pack 4b is started at the same time, the output current Ibat of the AC adapter 2 reaches the maximum output current I1, and the output characteristic of the AC adapter 2 unintentionally shifts to the constant current charging region X (see FIG. 3). There is a risk that

When this happens, the AC adapter 2
The output voltage Vcc of the charging circuit 14 may drop below the operation guarantee voltage V5 of the charging circuit 14, and the charging circuit 14 may not be able to perform proper charging control in the normal charging sequence. Further, if the balance of current supply to the charging circuits 14 and 32 is lost and one of the charging currents Ibat1 and Ibat2 is reduced, full charging may be erroneously detected and normal charging control may not be performed. Furthermore, when the total load exceeds the maximum output current I1 of the AC adapter 2, the AC adapter 2 may detect an abnormal current and cut off the output.

In order to avoid such a trouble of simultaneous charging, when the battery pack 4a and the spare battery pack 4b are simultaneously charged, it is only necessary to determine that the AC adapter 2 has the simultaneous power supply capability. It is necessary to control so as to charge 4b. Therefore, the protection circuit 145 of the present embodiment determines whether or not the backup battery pack 4b can be charged based on the output voltage Vcc of the AC adapter 2.
In order to control the charging of the spare battery pack 4b on / off, a charge control signal (hereinafter, referred to as a constant current charge control circuit 144
It is configured to output a RES signal).

Here, the protection circuit 145 of this embodiment is
The output level of the generated RES signal is set to the L level when the output voltage Vcc of the AC adapter 2 exceeds the first threshold voltage V3, and is set to the second threshold. When it falls below the voltage V4 (<V3), it is set to the H level. The first threshold voltage V
3 shows the output characteristics of the AC adapter 2 in the constant voltage charging area Y
(See FIG. 3) The constant voltage control start voltage V2 is set near the start voltage V2, and the second threshold voltage V4 is set to the charging circuit 1
4 is set sufficiently higher than the operation guarantee voltage V5.

On the other hand, the constant current charging control circuit 1 of this embodiment
44, the RES signal output from the protection circuit 145 is L
When the level is on, charging of the spare battery pack 4b is turned on, and H
It has a function to turn off charging when the level is reached.

That is, the protection circuit 145 of the present embodiment.
If the output voltage Vcc is higher than the first threshold voltage V3, it is determined that the AC adapter 2 has the simultaneous power supply capability, and the charging of the spare battery pack 4b is turned on, while the output voltage Vcc is the second threshold voltage. If the voltage is below V4, AC
It can be said that it is a circuit that turns off the charging of the spare battery pack 4b when it is determined that the adapter 2 does not have the simultaneous power supply capability.

By providing the protection circuit 145 as described above, when the battery pack 4a and the spare battery pack 4b, both of which are in an empty charge state, are charged at the same time, the battery pack 4a attached to the mobile phone 3 is charged first. , The battery pack 4
When the charging of a has advanced to some extent, the spare battery pack 4b
Will start charging. Therefore, the output voltage Vcc of the AC adapter 2 is the operation guarantee voltage V5 of the charging circuit 14.
Or the current supply balance to the charging circuits 14 and 32 is not disturbed, so that the above-mentioned troubles associated with simultaneous charging of a plurality of battery packs can be avoided.

Hereinafter, the operations of the constant current charging control circuit 144 and the protection circuit 145 described above will be described more specifically in accordance with the actual charging operation.

First, the battery pack 4a and the spare battery pack 4
The charge control characteristics when charging b simultaneously will be described. FIG. 4 is a diagram showing charge control characteristics when the battery pack 4a and the spare battery pack 4b are simultaneously charged, the vertical axis shows voltage and current, and the horizontal axis shows elapsed time from the start of charging.

In the figure, Vcc is the output voltage of the AC adapter 2, Vbat1 and Vbat2 are the output voltages of the charging circuits 32 and 14 (the terminal voltages of the battery pack 4a and the spare battery pack 4b), and V1 is the AC. The rated output voltage of the adapter 2, V2 is the constant voltage control start voltage of the AC adapter 2, V3 and V4 are the first and second threshold voltages of the protection circuit 145 (charge on / off detection voltage of the spare battery pack 4b), and V5 is The operation guarantee voltage of the charging circuit 14, V6 is the rated output voltage of the charging circuits 14 and 32, Ibat is the output current of the AC adapter 2, Ibat1 and Ibat2 are the charging currents for the battery pack 4a and the spare battery pack 4b (the charging circuit 32). , 14), I1 is the maximum output current of the AC adapter 2, I2 is the rated output current of the AC adapter 2,
I3 is a constant current set value preset in the charging circuit 14,
4 and I5 are full charge detection currents of the charging circuits 32 and 14,
Are shown respectively.

First, the charge control characteristics from the start of charging to time T1 (single charging period of the battery pack 4a) will be described.

When the mobile phone 3 is attached to the charger 1, the charging current Ibat1 in the battery pack 4a becomes A
The maximum output current I1 of the C adapter 2 starts to flow. At this time, since the terminal voltage Vbat1 of the battery pack 4a is low and the internal impedance is also low, the output voltage Vcc of the AC adapter 2 is the charge-on detection voltage V3 of the backup battery pack 4b.
Is less than In such a state, the charging circuit 14 is turned off by the protection circuit 145, so that the charging current Ibat2 to the spare battery pack 4b does not flow. Therefore, the terminal voltage Vbat2 of the spare battery pack 4b is not charged and remains at the initial value.

On the other hand, the battery pack 4a mounted on the mobile phone 3 has the charging circuit 3a immediately after the start of charging as described above.
Charged by 2. At this time, as the charging current Ibat1 to the battery pack 4a, the maximum output current I1 of the AC adapter 2 is supplied almost as it is, and the charging control in the constant current charging region X (see FIG. 3) described above is performed.

As described above, in the period from the start of charging to the time T1, as if the battery pack 4a reaches the terminal voltage Vbat1 near the rated output voltage V6.
The battery pack 4a has the charging characteristics as if it were charged by itself.
Charging progresses.

Next, from time T1 to time T2 (simultaneous charging period of battery pack 4a and spare battery pack 4b [first half])
The charge control characteristic of is described.

Battery pack 4a mounted on the mobile phone 3
When the charging of the AC adapter 2 progresses and the output voltage Vcc of the AC adapter 2 rises and reaches the vicinity of the constant voltage control start voltage V2, the charging circuit 32 gradually starts decreasing the charging current Ibat1 to the battery pack 4a. On the other hand, the output voltage Vc of the AC adapter 2
c rises and the charge-on detection voltage V of the spare battery pack 4b is detected.
When the number exceeds 3, the RES signal output from the protection circuit 145 becomes L level, so that the constant current charge control circuit 144 starts charging the spare battery pack 4b.

When the charging of the spare battery pack 4b is started, the output current Ibat of the AC adapter 2 increases, so that the output voltage Vcc of the AC adapter 2 sharply drops. At this time, if the output voltage Vcc of the AC adapter 2 falls below the charge-off detection voltage V4 of the backup battery pack 4b, the RES signal output from the protection circuit 145 becomes H level, so the backup battery by the constant current charge control circuit 144 is used. Pack 4
The charging of b is stopped. As a result, the load current Ibat of the AC adapter 2 starts to decrease again, so that the output voltage Vcc of the AC adapter 2 suddenly rises and the charging of the spare battery pack 4b is restarted.

As described above, in the period from time T1 to time T2, the AC adapter 2 is in the area indicated by the shaded area A.
The charging on / off of the spare battery pack 4b is repeated within a range in which the output current Ibat of the above does not exceed the maximum output current I1. During this time, the spare battery pack 4
As the charging of b progresses, the charging current Ibat2 gradually increases. On the other hand, the battery pack 4a attached to the mobile phone 3 is continuously charged while the charging current Ibat1 is reduced regardless of whether the spare battery pack 4b is charged or not.

Next, from time T2 to time T3 (simultaneous charging period of the battery pack 4a and the spare battery pack 4b [second half])
The charge control characteristic of is described.

As the charging of the battery pack 4a and the spare battery pack 4b progresses, the output current Ibat of the AC adapter 2 is increased.
Is less than the maximum output current I1 and near the rated output current I2, the output voltage Vcc of the AC adapter does not fall below the charge-off detection voltage V4 of the spare battery pack 4b, so the spare battery pack 4b is always in the charge-on state, Continuous charging is performed at the constant current setting value I3.

On the other hand, the charging current Ibat1 of the battery pack 4a attached to the mobile phone 3 further decreases as the charging progresses. Then, the charging current Ib of the battery pack 4a
When at1 drops to the full-charge detection current I4 of the charging circuit 32 or when the terminal voltage Vbat1 of the battery pack 4a rises to a voltage corresponding to the charging completed state, the charging circuit 32 determines that charging of the battery pack 4a is completed. Then, the recharge standby mode is entered, and the charging of the battery pack 4a is stopped.

Next, the charge control characteristics from time T3 to time T5 (single charging period of the spare battery pack 4b) will be described.

Even after the charging of the battery pack 4a is completed, the spare battery pack 4b is continuously charged at the constant current setting value I3. The charging of the spare battery pack 4b progresses, and at time T4,
When the terminal voltage Vbat2 of the spare battery pack 4b reaches near the rated output voltage V6 of the spare battery pack 4b, the charging circuit 14 causes the charging current Ibat2 to the spare battery pack 4b.
Gradually lower. Then, the charging current Ibat2 of the spare battery pack 4b is equal to the full-charge detection current I5 of the charging circuit 14.
Or the terminal voltage Vba of the spare battery pack 4b
When t2 rises to a voltage corresponding to the charging completed state, the charging circuit 14 determines that the charging of the spare battery pack 4b is completed, and shifts to the recharging standby mode, where the backup battery pack 4b
The charging of b is stopped.

As described above, the charger 1 of this embodiment is
When the battery pack 4a and the spare battery pack 4b are simultaneously charged, the output current Ibat of the AC adapter 2 is set between the maximum output current I1 of the AC adapter 2 and the vicinity of the rated output current I2 so that the battery pack 4a and Spare battery pack 4
The configuration is such that the charging currents Ibat1 and Ibat2 to b are controlled. With such a configuration, the output voltage Vcc of the AC adapter 2 can be constantly output in a stable manner, so that the battery pack 4a and the spare battery pack 4b can be properly charged and controlled.

Next, the charge control characteristics when the battery pack 4a is charged individually will be described. Figure 5 shows the battery pack 4
It is a figure which shows the charge control characteristic at the time of single charge of a, A vertical axis | shaft has shown the voltage and current, and the horizontal axis has shown the elapsed time from the start of charge. The variables (Vc
c, Vbat1, V1, V2, V6, Ibat, Iba
(t1, I1, I2, I4) all represent the same variables as in FIG.

When the mobile phone 3 is attached to the charger 1, the maximum output current I1 of the AC adapter 2 starts to flow in the battery pack 4a as the charging current Ibat1. At this time, since the terminal voltage Vbat1 of the battery pack 4a is low and the internal impedance is also low, the output voltage Vcc of the AC adapter 2 is reduced.
Becomes a state in which the constant current control start voltage V2 is not reached. Therefore, since the output characteristic of the AC adapter 2 is the constant current charging region X (see FIG. 3) described above, the output current Ibat of the AC adapter 2 is irrespective of the rise of the output voltage Vcc.
The maximum output current I1 exceeding the rated output current I2 is maintained in the vicinity.

As the charging of the battery pack 4a progresses, the output voltage Vcc of the AC adapter 2 rises and the constant voltage control start voltage V
When the battery charge reaches the vicinity of 2, the charging circuit 32 turns on the battery pack 4a.
The charging current Ibat1 to the battery starts gradually decreasing. Due to such current limitation, the output current Ibat of the AC adapter 2
Is less than or equal to the rated output current I2, the charging of the battery pack 4a is continued in a state where the output voltage Vcc of the AC adapter 2 is maintained near the rated output voltage V1 (constant voltage charging region Y). .

Then, the charging current Iba of the battery pack 4a
When t1 drops to the full-charge detection current I4 of the charging circuit 32 or the terminal voltage Vbat1 of the battery pack 4a rises to a voltage corresponding to the charging completed state, the charging circuit 32 determines that the charging of the battery pack 4a is completed. Then, the recharge standby mode is entered, and the charging of the battery pack 4a is stopped.

Next, the charge control characteristics when the spare battery pack 4b is charged alone will be described. FIG. 6 is a diagram showing charge control characteristics when the battery pack 4b is charged by itself, the vertical axis shows voltage and current, and the horizontal axis shows elapsed time from the start of charging. The variables (Vcc, Vbat2, V1, V2, V6, Ibat,
Ibat2, I2, I3, I5) all indicate the same variables as in FIG.

When the spare battery pack 4b is attached to the charger 1, the charging current Ibat2 starts to flow through the spare battery pack 4b. At this time, as described above, the current value of the charging current Ibat2 is equal to or less than the rated output current I2 of the AC adapter 2 by the constant current charging control circuit 144 (constant current setting value I3).
Controlled by. Therefore, unlike the battery pack 4a attached to the mobile phone 3, the spare battery pack 4b has a constant voltage charging area Y (see FIG. 3) from the beginning of charging.
Charging control is performed.

With such a configuration, the output voltage Vcc of the AC adapter 2 is always maintained near the rated output voltage V1 of the AC adapter 2 while the spare battery pack 4b is being charged. Therefore, even if the spare battery pack 4b in the over-discharged state is mounted on the charger 1, the output voltage Vcc of the AC adapter 2 is reduced by the protection circuit 145 due to the action of the protection circuit 145. The charging circuit 14 does not malfunction.

When the charging of the spare battery pack 4b progresses and the terminal voltage Vbat2 of the spare battery pack 4b rises to reach the vicinity of the rated output voltage V6, the charging circuit 14 gradually supplies the charging current Ibat2 to the spare battery pack 4b. Start lowering. Then, when the charging current Ibat2 drops to the full-charge detection current I5 of the charging circuit 14 or the terminal voltage Vbat2 of the backup battery pack 4b rises to a voltage corresponding to the charging completed state, the charging circuit 14 charges the backup battery pack 4b. Is determined to have been completed, the recharge standby mode is entered, and charging of the spare battery pack 4b is stopped.

[0066]

As described above, the charger according to the present invention includes the first power supply terminal for charging the secondary battery having no charge control function in a state where the secondary battery is mounted on the electric device, and the secondary battery. And a charging circuit for charging the secondary battery connected to the second power supply terminal. The charging operation of the secondary battery connected to the second power supply terminal is controlled to be turned on / off based on the input voltage.

With such a configuration, the first,
When simultaneously charging the secondary battery connected to the second power supply terminal, first charge the secondary battery connected to the first power supply terminal, and when the secondary battery is charged to a certain degree, the second battery is charged. Charging of the secondary battery connected to the power supply terminal can be started. Therefore, the output voltage of the power supply device that supplies power to the charging circuit does not fall below the operation guarantee voltage of the charging circuit, or the current supply balance to each charging circuit is not disturbed. It is possible to avoid troubles caused by simultaneous charging of the secondary batteries without increasing the size. In addition, in order to maximize the power supply capacity of the power supply device, charging of the secondary battery connected to the second power supply terminal is started without waiting for completion of charging of the secondary battery connected to the first power supply terminal. Therefore, it is possible to shorten the time required until the completion of the charging of the latter, as compared with the configuration in which the charging of the other is started after the completion of the charging of the one.

In the charger having the above structure,
The charging circuit has a protection circuit that turns on the charging operation of the secondary battery connected to the second power supply terminal when the input voltage to the charging circuit exceeds a first threshold value, and turns off the charging operation when the input voltage falls below the second threshold value. It is recommended that the configuration be configured as follows. With such a configuration, when the secondary batteries connected to the first and second power feeding terminals are simultaneously charged, the output current of the power supply device falls between the maximum output current and the vicinity of the rated output current. Thus, the charging current to each secondary battery can be controlled. Therefore, the output voltage of the power supply device can be constantly output in a stable manner, so that it is possible to correctly control the charging of the secondary batteries. Further, since the protection circuit according to the present invention has a very simple structure, it can contribute to cost reduction of the charging circuit.

In the charger having the above structure,
The charging circuit has means for maintaining the charging current to the secondary battery connected to the second power supply terminal at a rated output current or less of a power supply device for supplying power to the charging circuit. Good to do. With such a configuration, even if a slight load change occurs on the electric device side connected to the first power supply terminal, the output voltage of the power supply device is unlikely to change, so that the protection circuit malfunctions. It is difficult, and the charging operation of the secondary battery connected to the second power supply terminal can be stably continued without interruption. Therefore, it is possible to avoid the problem that the state of charge of the secondary battery connected to the second power supply terminal changes each time the electric device is operated during charging, and the state of charge display lamp repeatedly turns on and off. it can.

[Brief description of drawings]

FIG. 1 is a schematic configuration diagram showing an embodiment of a charger and peripheral devices according to the present invention.

FIG. 2 is a schematic vertical cross-sectional view of a charger and peripheral devices according to the present invention.

FIG. 3 is a diagram showing output characteristics of the AC adapter 2.

FIG. 4 is a diagram showing charge control characteristics when the battery pack 4a and the spare battery pack 4b are simultaneously charged.

FIG. 5 is a diagram showing charge control characteristics when the battery pack 4a is individually charged.

FIG. 6 is a diagram showing charge control characteristics when the backup battery pack 4b is charged alone.

FIG. 7 is a schematic configuration diagram showing an example of a conventional charger and peripheral devices.

FIG. 8 is a schematic configuration diagram showing another example of a conventional charger and peripheral devices.

[Explanation of symbols]

1 charger 11 Power receiving connector 12 First power supply terminal (for charging mobile phones) 13 Second power supply terminal (for charging spare battery pack) 14 Charging circuit 141 transistor 142 diode 143 resistance 144 constant current charging control circuit 145 protection circuit 15 circuit board 16 First recess (for mounting mobile phones) 17 1st lock claw (for fixing mobile phone) 18 Second recess (for mounting spare battery pack) 19 2nd lock claw (for fixing spare battery pack) 2 AC adapter 21 AC plug 22 Power circuit 23 Constant current constant voltage circuit 24 power supply connector 3 mobile phones 31 Power receiving electrode 32 charging circuit 321 diode 322 transistor 323 Internal circuit 4a battery pack 4b Spare battery pack 41a, 41b secondary battery cell Vcc Output voltage of AC adapter 2 Output voltage of Vbat1 charging circuit 32 Vbat2 Output voltage of charging circuit 14 Rated output voltage of V1 AC adapter 2 V2 AC adapter 2 constant voltage control start voltage First threshold voltage of V3 protection circuit 145 Second threshold voltage of V4 protection circuit 145 V5 Charging circuit 14 operation guarantee voltage Rated output voltage of V6 charging circuit 14, 32 Output current of Ibat AC adapter 2 Ibat1 Charge current to the battery pack 4a Ibat2 Charging current to spare battery pack 4b Maximum output current of I1 AC adapter 2 I2 AC adapter 2 rated output current I3 Constant current preset value for charging circuit 14 I4 Full charge detection current of charging circuit 32 I5 Full charge detection current of charging circuit 14 X constant current charging area Y constant voltage charging area

Claims (3)

[Claims] 1. A first power supply terminal for charging a secondary battery, which does not have a charge control function, in a state of being mounted in an electric device,
A second power feeding terminal for charging the secondary battery in a state where the secondary battery is not mounted on the electric device; and a charging circuit for controlling charging of the secondary battery connected to the second power feeding terminal, A charger characterized by performing on / off control of a charging operation of a secondary battery connected to a second power supply terminal based on an input voltage to a charging circuit. 2. The charging circuit turns on a charging operation of a secondary battery connected to a second power supply terminal when an input voltage to the charging circuit exceeds a first threshold value, and turns off when the input voltage falls below a second threshold value. The charger according to claim 1, further comprising a protection circuit. 3. The charging circuit has means for maintaining the charging current to the secondary battery connected to the second power supply terminal at a rated output current or less of a power supply device for supplying power to the charging circuit. The battery charger according to claim 1 or 2, wherein the battery charger comprises: