JPH0956082A - Battery charger - Google Patents

Abstract

PROBLEM TO BE SOLVED: To enable a battery charger to charge a battery by automatically switching the charging mode and, at the same time, to reduce the size of the charger by setting protective timer to the charging time in accordance with the power output capacity and outputting a charging current for the charging time, and then, stopping the output of the charging current after the charging time has elapsed. SOLUTION: When starting charging, a control means 103 calculates the output capacity of a power source 101 from the detected results of a charging current detecting means 105 and sets at protective timer to the charging time from the output capacity of the power source 101. Then the control means 103 controls an output control means 106 to output a charging current until the charging time comes set to the protective timer and to stop the output of the charging current after the charging time has elapsed. Since the protective timer is automatically set in accordance with the output capacity of the power source 101 by detecting the charging current in such a way, a battery can be charged by automatically switching the charging mode and no hardware having a large circuit scale is required. Therefore, The size of a charging circuit can be reduced.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a battery charger, and more particularly to a battery charging device capable of detecting a charging current to identify the type or capacity of a battery and automatically switching between charging modes. The present invention relates to a battery charging device that does not require hardware with a large circuit scale and can be downsized.

[0002]

2. Description of the Related Art Conventionally, in a battery charging device such as a Ni-Cd battery, in addition to standard charging, full charging without overcharging or rapid charging in which a larger charging current is performed in a short time is performed. Various configurations have been proposed that can deal with auxiliary charging (trickle charging) for charging.

For example, a charging current corresponding to each of standard charging, rapid charging and supplementary charging is provided with a constant current circuit capable of switching output, or another additional circuit for rapid charging is provided to be used by switching. There is a battery charger with a configuration.

[0004]

However, in the above-mentioned conventional battery charger, according to the user's request,
Alternatively, the user has to manually set the charging mode according to the type of the battery and the battery capacity, and there is a problem in that complete automation cannot be achieved.

Further, there is a problem that a relatively large hardware having a large circuit scale such as a constant current circuit requiring a radiator and an additional circuit for rapid charging is required, and the device cannot be downsized. .

The present invention has been made in view of the above-mentioned conventional problems, and a battery pack in which a battery to be charged includes a unique identification element for identifying the type or capacity of the battery. It is an object of the present invention to provide a battery charger that can identify the type or capacity based on the detection of the charging current and automatically switch the charging mode to perform charging.

Another object of the present invention is to provide a battery charger capable of miniaturizing the device by eliminating the need for relatively complicated hardware having a large circuit scale such as a constant current circuit requiring a radiator. is there.

[0008]

In order to solve the above-mentioned problems, the battery charging device of the first feature of the present invention comprises a power source for charging, an output control means for controlling the output current of the power source,
A battery charged by the output of the output control means, a charging current detection means for detecting the charging current of the battery, a protection timer for setting the charging time of the battery, and a charging start time,
The output capacity of the power supply is calculated based on the result of the charging current detection means, the charging time is set in the protection timer based on the output capacity of the power supply, and the output control means sets the charging time according to the protection timer until the charging time is reached. And a control means for outputting the charging current and stopping the output of the output control means after the charging time has elapsed.

A second aspect of the present invention is a battery charging device, a power source for charging, output control means for controlling an output current of the power source, and a battery charged by the output of the output control means. A battery pack including an identification element having a unique physical quantity for identifying the type or capacity of the battery; a charging current detection means for detecting a charging current or a part of the charging current flowing through the identification element; and the battery And a protection timer for setting the charging time of the battery, and at the start of charging, the capacity of the battery is calculated based on the result of the charging current detection means, the charging current is determined based on the battery capacity, and the battery capacity and the charging current are determined. Set the charging time to the protection timer based on
According to the protection timer, there is provided control means for causing the output control means to output the determined charging current until the charging time, and stopping the output of the output control means after the charging time has elapsed.

The battery charging device of the third aspect of the present invention is the battery charging device according to claim 1 or 2, wherein the power source can control the output capacity or the output voltage.

A fourth aspect of the present invention is the battery charger of claim 1, wherein the output control means is turned on / off according to a control signal from the control means. The switching means outputs the charging current determined by periodic ON / OFF control during charging.

A fifth aspect of the present invention is the battery charger according to claim 1, 2, or 3, wherein the battery charger has a pulse width corresponding to a control signal from the control means. Drive means for generating a pulse width modulation signal, the output control means is switching means for turning on / off according to the pulse width modulation signal from the driving means, and the pulse width modulation signal is supplied during charging. The charging current determined by the ON / OFF control of is output.

A sixth aspect of the present invention is the battery charging device according to any one of claims 1, 2, 3, 4 or 5, wherein the battery charging device detects the voltage of the battery. The control means is provided with a detecting means, and when the control means determines from the detection result of the voltage detecting means that the voltage of the battery has reached a voltage value of a fixed ratio of the rated voltage, the control timer is reset and reset at a predetermined time. After setting, supplementary charging is performed with a predetermined minute charging current.

Furthermore, the battery charging device of the seventh feature of the present invention is the battery charging device according to claim 1, 2, 3, 4, 5 or 6, wherein the control means is a microcomputer.

[0015]

BEST MODE FOR CARRYING OUT THE INVENTION Hereinafter, an outline of a battery charger of the present invention and an embodiment of a battery charger of the present invention will be described in order of [First Embodiment] and [Second Embodiment] with reference to the drawings. The details will be described.

[Outline of Battery Charging Device of the Present Invention] FIG.
It is a principle explanatory view of the battery charging device concerning the present invention. In the figure, 101 is a power source for charging, 106 is output control means for controlling the output current of the power source 101, 102 is a battery charged by the output of the output control means 106, and 104 is a battery 1
02 is an identification element having a unique physical quantity (R) for identifying the type or capacity, 110 is a battery pack including the battery 102 and the identification element 104, 105 is the charging current of the battery 102, or the identification element 104 flows. Charging current detecting means for detecting charging current or part of charging current, 103
Is a control means, and 107 is a voltage detection means for detecting the voltage of the battery 102. The control means 103 includes a battery 102.
Timer and pulse width modulation signal V to set the charging time of
It includes drive means for generating s.

In the battery charging device of the first feature of the present invention,
At the start of charging, the control means 103 controls the charging current detecting means 1
The output capacity of the power supply 101 is calculated based on the result of 05,
The charging time is set in the protection timer based on the output capacity of the power source 101, the charging current is output from the output control means 106 until the charging time is reached according to the protection timer, and the output of the output control means 106 is output after the charging time elapses. I'm trying to stop it. In this way, the charging current is detected and the power supply 1
Since the protection timer is automatically set according to the output capacity of 01, relatively complex and large-scale hardware such as a constant current circuit requiring a radiator is not required, and the device can be downsized.

Further, in the battery charger of the second feature of the present invention, at the start of charging, the control means 103 controls the capacity of the battery 102 based on the charging current flowing through the identification element 104 detected by the charging current detecting means 105. Calculate the battery 1
The charging current is determined based on the capacity of 02, the charging time is set in the protection timer based on the battery capacity and the charging current, and the determined charging current is output from the output control means 106 until the charging time is reached according to the protection timer. The output is performed, and the output of the output control unit 104 is stopped after the charging time has elapsed.

In this way, the battery 10 is detected by detecting the charging current.
Since the charging current is determined according to the capacity of 2 and the protection timer is automatically set according to the battery capacity and the determined charging current, manual switching work according to the charging mode is unnecessary and automation can be achieved. At the same time, relatively complicated and large-scale hardware such as a constant current circuit that requires a radiator is not required, and the device can be downsized.

Further, in the battery charger of the third feature of the present invention, it is desirable that the power supply 101 can control the output capacity or output voltage. As a result, an appropriate charging current can be set according to each charging mode, and charging can be performed accurately.

Further, in the battery charger of the fourth feature of the present invention, the output control means 106 is a switching means which is turned on / off according to the control signal Vs from the control means 103, and is periodically charged during charging. The charging current determined by the on / off control is output.

Further, the battery charger of the fifth feature of the present invention is provided with a driving means (not shown) for generating a pulse width modulation signal Vs having a pulse width according to the control signal from the control means 103, The output control means 106 is a switching means for turning on / off according to the pulse width modulation signal Vs from the driving means, and outputs a charging current determined by on / off control of the pulse width modulation signal Vs during charging. I have to.

Further, in the battery charger of the sixth feature of the present invention, the control means 103 judges that the voltage of the battery 102 has reached a voltage value of a fixed ratio of the rated voltage, based on the detection result of the voltage detection means 107. At times, the protection timer is reset and reset to a predetermined time, after which supplementary charging with a predetermined minute charging current is performed.

Further, in the battery charger of the seventh feature of the present invention, it is desirable that the control means 103 is realized by a microcomputer. The digital control of the microcomputer enables even finer and more flexible control.

[Embodiment 1] FIG. 2 is a configuration diagram of a battery charger according to Embodiment 1 of the present invention. In the figure, the battery charger of this embodiment is a battery charger applied to, for example, a mobile phone system, and includes a power source 101 for charging, a charger 201, a battery pack 202 to be charged, and
The telephone unit 203 is provided.

The charger 201 is a charging stand, and is provided with only a resistor 211 for current-voltage conversion and current limitation inside. In addition, the battery pack 202 is configured to include a battery 102 such as a Ni—Cd battery and a resistor 212 (identification element in the claims) inside. Battery pack 20
The resistor 212 in 2 determines one input potential in the differential amplifier circuit described later, and the resistance value R2 is the battery 10
It is set individually in advance according to the capacity of 2.

In the telephone unit 203, a differential amplifier circuit for charging current detection (charging current detection means) and an A / D converter 20 are provided for charging the battery.
4, a control means 103 including a microprocessor 205 and a drive circuit 206, a transistor 221 (output control means in the claims) which is switching-controlled by the control means 103, and a diode for blocking the flow of the charging current in the opposite direction. 220 is provided.

Therefore, in the control means 103 of this embodiment,
Operation control related to battery charging is realized by digital control. Further, the voltage detecting means in the claims is such that the microprocessor 205 is connected to one terminal of the diode 220.
Corresponds to the signal line of the detection voltage ΔV supplied to.

The differential amplifier circuit for detecting the charging current is composed of resistors 211 to 218 and a differential amplifier 219. Between the output voltage Vdd of the power source 101 and the ground potential GND, resistors 212 and 213 and a resistor 214 are provided. The differential amplifier 219 takes the difference between the potential divided by and the potential divided by the resistors 211 and 216 and the resistor 217.

That is, the differential voltage which is the output of the differential amplifier 219 serves as a parameter for detecting the charging current as a physical quantity related to the potential difference across the resistor 211 connected in series to the charging current path. Also, the differential voltage detected by the differential amplifier circuit is converted into a digital value Vcur by the A / D converter 204, and the microprocessor 205
Is taken into.

The drive circuit 206 is the microprocessor 2
The pulse width modulation signal pwm corresponding to the drive circuit control voltage Vref from 05 is generated. The transistor 221 is turned on and the charging current is supplied to the battery 102 only while the pulse width modulation signal pwm is at the “H” level (pulse width Ton). The relationship between the period T of the pulse width modulation signal pwm and the pulse width Ton is represented by the duty ratio defined by the following equation. Duty ratio = Ton / (T / 2) [%]

As the drive circuit 206, for example, a configuration using an operational amplifier as shown in FIG. 4 can be considered. In the concrete example shown in FIG. 4, a triangular wave is generated by the operational amplifiers 401 and 402, and the triangular wave is compared by the operational amplifier 403 (comparator) with a potential determined by the value of the power supply VCC and the variable resistor 407 to generate a pulse. This is a configuration for generating the width modulation signal pwm. The pulse width is set by changing the value of the variable resistor 407 according to the drive circuit control voltage Vref to control the potential applied to the (+) terminal of the operational amplifier 403.

A well-known frequency divider may be used as the drive circuit 206. When the drive circuit 206 is configured by the configuration of the operational amplifier and the configuration of the frequency divider, the means for generating the drive circuit control voltage Vref may be configured by using the general microprocessor 205. That is, if the above-mentioned operational amplifier is used,
The value of the variable resistor 407 is digitally controlled, and if the frequency divider is configured, the frequency division ratio is digitally controlled.

Further, a microcomputer having a pulse width modulation (PWM) mode, which has both the microprocessor 205 and the drive circuit 206, for example, "H8 / 3048" manufactured by Hitachi, Ltd. may be used. This microcomputer can select the counter clock and the counter clear factor, and outputs 1/0 of the output signal waveform.
By setting the output timing in a register and setting it in the PWM mode, a pulse signal with a predetermined pulse width modulation is output.

The pulse width Ton is also designated by the program with respect to the period T determined by the frequency designated by programming. That is, in the above microcomputer, the period T is determined by the selection of the counter clock and the counter clear factor, and the pulse width Ton is determined by the contents of the register that sets the 1/0 output timing of the output signal waveform. By using such a high-performance microcomputer, higher integration can be realized and the device can be downsized.

Next, a specific operation of charging the battery pack 202 using the battery charger of this embodiment will be described.

First, when the specifications such as the power capacity of the power source 101 used for charging are unknown, or when the power source used is switched, the battery capacity or the charging current required for 1C charging is known. The power capacity is calculated using a different battery pack and xC charging (eg x is x =
A duty ratio and protection timer set time correspondence table according to the range (0.2 to 1) are configured.

Here, “xC in xC charging” represents the magnitude of the charging current amount with respect to the battery capacity B [mAh], and the current i required for xC charging is obtained by i = x × B [mA] . For example, battery capacity B = 600 [mAh]
The charging current i required to charge the above battery with 0.2 C charge (x = 0.2) is i = 600 × 0.2 = 120 [mA]
It is.

The protection timer setting time is the setting time of the software timer implemented in the microprocessor 205 or the hardware timer implemented in the control means 103. This protection timer is set with a time corresponding to the battery capacity and the charging current in order to prevent overcharging of the battery, and when the protection timer times out, the microprocessor 205 ends the charging of the battery 102. The microprocessor 205 can also display the remaining charging time on the display device in the telephone unit 203 based on the set time of the protection timer.

For the above standard battery, the duty ratio of the pulse width modulation signal pwm is set in a certain range (for example, 0
〜100 [%]), the charging current at that time is
Differential amplifier circuit and A / D converter 2 for detecting charging current
Based on the charging current detection differential voltage Vcur of 04, the microprocessor 205 obtains the difference.

By detecting the charging current, the duty ratio of the charging current required to perform 1C charging for the standard battery capacity is set as D1 and held in a data memory (not shown). Further, based on the duty ratio of the 1C charging, a correspondence table of the duty ratio and the protection timer set time corresponding to each charging current is constructed and held in the data memory. For example, the contents are as follows.

[0042]

[Table 1]

If the duty ratio of the pulse width modulation signal pwm is changed within a certain range and the charge current i1 required for 1C charging is not reached, the duty ratio is 10%.
A correspondence table of the duty ratio and the protection timer set time corresponding to each charging current is constructed according to the charging current i ′ at 0 [%], and is held in the data memory. For example,
The contents are shown below.

[0044]

[Table 2]

Next, the operation for charging an arbitrary battery pack 202 having the resistor 212 as an identification element will be described.

At the start of charging, the duty ratio is set to D1 or 100 [%], and the charging current at that time is based on the charging current detecting differential voltage Vcur by the charging current detecting differential amplifier circuit and the A / D converter 204. , Microprocessor 205 determines. Further microprocessor 2
05 determines, based on the detected charging current, what kind of xC charging should be performed for the battery pack,
By referring to the above correspondence table, the duty ratio is set to determine the charging current, and the time of the protection timer is set.

Further, when supplementary charging (trickle charging) is performed in order to fully charge the battery 102, a protection timer is set to a predetermined time to charge C / 25 or C / 30.
Charging is performed with a very small current for charging.

As described above, according to the battery charger of the present embodiment, the charging timer is detected and the protection timer is automatically set according to the output capacity of the power source 101. The hardware, which is relatively complicated and has a large circuit scale, such as a current circuit is not required, and the device can be downsized.

At the start of charging, the charging current is detected to determine the charging current according to the capacity of the battery 102, and the protection timer is automatically set according to the battery capacity and the determined charging current. It does not require manual switching work depending on the charging mode, and automation can be achieved. Also, relatively complex and large-scale hardware such as a constant current circuit that requires a radiator is not required, and the amount of hardware is large and complicated. Since it is not necessary to separately provide a charging circuit, the device can be downsized.

The power supply 101 may be of a type whose output capacity or output voltage can be controlled. In this case, an appropriate charging current can be set according to each automatically set charging mode, and charging can be performed accurately.

Further, in the case of performing rapid charging such as 1C charging, even if the capacity of the power supply 101 is insufficient and the charging current is less than the charging current required for 1C charging, the charging current corresponding to the capacity of the power supply 101 is used. Is automatically determined and the time of the protection timer is set according to the charging current, so that it is possible to realize a battery charging device that can flexibly deal with the device environment.

[Embodiment 2] FIG. 3 is a configuration diagram of a battery charger according to Embodiment 2 of the present invention. In the battery charging device of the present embodiment, the operation control relating to battery charging performed by the control means described in the claims is realized by analog control.

In FIG. 3, the battery charger of the present embodiment comprises a battery pack 302 to be charged, a charging power source (9
[V]) are supplied to terminals 306 (Vdc terminal) and 30
7 (GND terminal), regulator 303, timer circuit 3
04, battery voltage detection circuit 305 (voltage detection means 107 in the claims), charging current detection circuit (charging current detection means 1
05), a transistor 325 (output control means 106),
A current control circuit (control means 103) for analog-controlling the collector current of the transistor 325, and a trickle charge control circuit for switching quick charge or standard charge to trickle charge are provided as peripheral circuits of the timer circuit 304.

In the battery pack 302, a battery 102 such as a Ni-Cd battery and a resistor 312 (identification element referred to in the claims).
Is provided. The resistor 312 in the battery pack 302 determines the detection gain of the charging current detection circuit described later, and the resistance value R10 is individually set in advance according to the capacity of the battery 102. In FIG. 3, reference numerals 308 to 311 are charging terminals that connect the battery charging device and the battery pack 302, and 341 and 342 are connected to devices that use the battery pack 302, such as a telephone unit. It is a terminal.

The charging current detecting circuit (charging current detecting means 105) for detecting the charging current is composed of a transistor 328.
˜332, resistors 312 and 321 to 324.

First, the transistor 332 is made to function as a diode, current-voltage conversion is performed by the resistor 324, and the base voltage (instruction voltage V1) of the transistor 331 is obtained.
Has been decided. Here, the base voltage is supplied via the transistor 332 because the base-emitter voltage VBE of the transistor 331 and the transistor 332 is canceled by this, and the resistor 323 receives the resistor 3
This is because the same potential as 24 appears and the voltage is transmitted, so that the accuracy of current detection can be improved.

Next, voltage amplification is performed by the transistors 331 and 329 and the resistors 323 and 312, and the amplified voltage (instruction voltage V2) is transmitted to the resistor 321.
In addition, transistors 328 and 330 and resistor 321
And 322 perform voltage amplification, and the amplified voltage (instruction voltage V3) is supplied to the current control circuit.

Next, a current control circuit (control means 103) for analog-controlling the collector current of the transistor 325.
Are transistors 326 and 327 and a resistor 32.
It is configured with 0.

The current control circuit compares the instruction voltage V5 with the instruction voltage V3 and controls the collector current flowing through the transistor 325 so that the instruction voltage V5 and the instruction voltage V3 match. The instruction voltage V5 is the regulator 303
Output voltage 5 [V] is applied by being divided by resistors 313 and 317. Electrolytic capacitor 334 stabilizes instruction voltage V5.

Next, the battery voltage detection circuit 305 determines that the battery 1
A potential V4 obtained by dividing the voltage of 02 by resistors 318 and 319.
Start signal START and stop signal STO according to
The P and reset signal RESET is output to the timer circuit 304. When the battery 302 is set as the start signal START and a voltage is generated between the charging terminals 308 and 311 (the potential V4 becomes a predetermined voltage or more), the stop signal STOP is when the battery 302 is charged and the charging terminal 308-
The voltage between 311 has reached a voltage value of a fixed ratio of the rated voltage of the battery 302 (the potential V4 has reached the rated equivalent voltage −ΔV).
When this is detected, the reset signal RESET indicates that the battery 3
When 02 is removed and the voltage between the charging terminals 308-311 becomes an open circuit voltage (potential V4), each becomes active and controls the timer circuit 304.

A trickle charge control circuit for switching the quick charge or the standard charge to the trickle charge as a peripheral circuit of the timer circuit 304 is a switching circuit including resistors 314 to 316 and a transistor 333. When the battery voltage detection circuit 305 detects that the quick charge or the standard charge has been completed (the potential V4 has reached the rated equivalent voltage −ΔV), the transistor 333 is turned on by the output of the timer circuit 304, and the rapid charge is performed. The instruction voltage V5 for charging or standard charging shifts to the instruction voltage V5 for trickle charging.

Next, the operation of the circuit will be described by assigning specific numerical values to the circuit constants in FIG. In this specific example, the power transistor 2SB1127 is used as the transistor 325.
(PC15 [W]), 2SC4181 is used for the transistors 326, 327 and 330, 2SA1179 is used for the transistors 328 and 329, and 2SD2100 is used for the transistors 331 and 332.

First, the relationship between the capacity of the battery 102 and the resistance value R10 of the resistor 312 (identification element) is set as follows.

In the battery charger of this embodiment, in the differential amplifier composed of the transistors 326 and 327,
Transistor 3 so that the indication voltages V3 and V5 match
25 is controlled, so V3 = (R10.R20.R22 / R19.R21) .I + VBE (1) where I is the charging current (see FIG. 3).

Now, the resistors 321 to 324 are respectively connected to R19.
= 330 [Ω], R20 = 1 [kΩ], R21 = 100
When [Ω] and R22 = 1 [Ω] are set, V3 = 0.03R10 · I + VBE (2) A battery of 600 [mAh] is used as a reference, and
If C charging is performed, V3 = 0.03 × 100 × 0.6 + 0.7 = 2.5 [V] Since this voltage matches the instruction voltage V5,
When V5 = 2.5 [V], the resistors 313 and 317 have R11 = R15, which is 2.2 [kΩ].

From the equation (2), V5 = 0.03R10 · I + VBE can be set, and the charging current I can be summarized as follows: I = (V5-VBE) /0.03R10=60/R10 (3)

Accordingly, if a resistance of R10 = 75 [Ω] is inserted in the battery pack 302 of 800 [mAh], I =
1C is charged with a charging current of 60/75 = 0.8 [A]. In addition, 1200 [mAh] battery pack 3
If a resistor of R10 = 50 [Ω] is put in 02, I = 60
1C is charged with the charging current of /50=1.2 [A].

Next, when the battery voltage detection circuit 305 detects that the quick charge or the standard charge is completed, the output of the timer circuit 304 turns on the transistor 333 to perform trickle charge. Since the current C / 25 to C / 30 is used as the trickle charging current for the instruction voltage V5 at that time, the relationship of (V5-VBE) /25=V3/25=0.072 [V] is established. Therefore, the instruction voltage V5 becomes V5 = 0.072 + 0.7 = 0.772 [V], and the resistance value of the resistor 316 that achieves this is R14.
= 400 [Ω]. On the contrary, this resistance value R14 = 400
The instruction voltage V5 set by [Ω] is V5 = {R14 / (R14 + R11)} · 5 = 0.769 [V]. Although slightly lower than the set voltage, C / 25 to C /
There is no problem in the range of 30.

As described above, in the battery charger of this embodiment, the resistance value R of the resistor 312 in the battery pack 302 is
Since the charging current according to the capacity of the battery 102 is determined by 10 and automatically adjusted, it is possible to automate without requiring manual switching work according to the charging mode, and a constant current circuit that requires a radiator as in the past. It is possible to reduce the size of the device by eliminating the need for relatively complicated hardware with a large circuit scale.

Finally, a characteristic difference between the battery chargers of the first and second embodiments will be compared and explained.

First, in the first embodiment, the telephone unit 203
This is a configuration in which most of the charging circuit is provided. Therefore, at the time of charging, the telephone unit 203 and the battery pack 202 are combined and set on the charger (charging stand) 101. On the other hand, the charger (charging stand) 101 has only a resistor 211 for current-voltage conversion and current limitation, and has a simple configuration. On the other hand, in the second embodiment, the device using the battery pack 302 such as a telephone unit does not have a charging circuit, and the charging circuit is provided on the charger side.

Further, in the first embodiment, since the telephone unit 203 has the charging function, it is possible to add various functions to the telephone unit 203. For example, it is possible to add functions such as displaying the charging time and resetting the charging time by a call during charging. On the other hand, in Example 2,
Such a function cannot be added because the device that uses the battery pack 302 such as a telephone unit does not have a charging circuit, but the charger side must have at most one timer setting function. It is good and the charger can be made cheaper.

[0073]

As described above, according to the battery charging device of the first feature of the present invention, at the start of charging, the control means calculates the output capacity of the power source based on the result of the charging current detection means, The charging time is set in the protection timer based on the output capacity of the power source, the charging current is output from the output control means until the charging time is reached according to the protection timer, and the output of the output control means is stopped after the charging time elapses. Since the charging current is detected and the protection timer is automatically set according to the output capacity of the power supply, relatively complicated and large-scale hardware such as a constant current circuit that requires a radiator is not required, and the device It is possible to provide a battery charging device that can be downsized.

Further, according to the battery charger of the second aspect of the present invention, at the start of charging, the control means calculates the capacity of the battery based on the charging current flowing through the identification element detected by the charging current detecting means. Then, the charging current is determined based on the capacity of the battery, the charging time is set in the protection timer based on the battery capacity and the charging current, and the charging current determined from the output control means until the charging time is reached according to the protection timer. Is output, the output of the output control means is stopped after the charging time has elapsed, the charging current is detected, the charging current is determined according to the capacity of the battery, and the charging current is determined according to the battery capacity and the determined charging current. Since the protection timer is set automatically,
It does not require manual switching work according to the charging mode, and automation can be achieved, and relatively complicated and large-scale hardware such as a constant current circuit that requires a radiator is not required.
It is possible to provide a battery charger capable of downsizing the device.

Further, according to the battery charging device of the third feature of the present invention, since the output capacity or the output voltage of the power source can be controlled, an appropriate charging current can be set according to each charging mode and the accuracy can be improved. It can be charged well.

Further, according to the battery charger of the fourth feature of the present invention, the output control means is the switching means which is turned on / off according to the control signal from the control means, and is periodically turned on during charging. The charging current determined by the ON / OFF control is output, and according to the battery charging device of the fifth feature of the present invention, the pulse width modulation signal having the pulse width corresponding to the control signal from the control means is output. A driving means for generating the output control means, as a switching means for turning on / off the pulse width modulation signal from the driving means,
Since the charging current determined by the ON / OFF control of the pulse width modulation signal is output during charging, it is possible to perform charging with high accuracy with a simpler configuration.

Further, according to the battery charger of the sixth aspect of the present invention, when the control means determines from the detection result of the voltage detection means that the voltage of the battery has reached a voltage value of a fixed ratio of the rated voltage. Since the protection timer is reset and reset for a predetermined time, supplementary charging with a predetermined minute charging current is performed, so that the battery can be fully charged automatically.

Further, according to the battery charging device of the seventh feature of the present invention, since the control means is realized by the microcomputer, it is possible to perform finer and more flexible control by digital control of the microcomputer.

[Brief description of drawings]

FIG. 1 is a diagram illustrating the principle of a battery charging device of the present invention.

FIG. 2 is a configuration diagram of the battery charging device according to the first embodiment of the present invention.

FIG. 3 is a configuration diagram of a battery charging device according to a second embodiment of the present invention.

FIG. 4 is a circuit diagram of a drive circuit that generates a pulse width modulation signal.

[Explanation of symbols]

 101 power supply 102 battery 103 control means 104 identification element 105 charging current detection means 106 output control means 107 voltage detection means 108 resistance 201 charger 202 battery pack 203 telephone unit 204 A / D converter 205 microcomputer 206 drive circuits 211 to 218 resistance 219 difference Dynamic amplifier 220 diode 221 transistor Vdd power supply voltage GND ground (potential) ΔV detection voltage Vcur charging current detection differential voltage Vref drive circuit control voltage pwm pulse width modulation signal 302 battery pack 303 regulator 304 timer circuit 305 battery voltage detection circuit 306 to 311 , 341, 342 Terminals 312-324 Resistances 325-333 Transistors 334 Electrolytic capacitors 401, 402, 403 Operational amplifier 4 4～406,408～413 resistance 407 variable resistor 414 and 415 capacitor

Claims (7)

[Claims] 1. A power source for charging, an output control means for controlling an output current of the power source, a battery charged by an output of the output control means, and a charging current detection means for detecting a charging current of the battery. A protection timer that sets the charging time of the battery, and at the start of charging, calculates the output capacity of the power supply based on the result of the charging current detection means, and sets the charging time in the protection timer based on the output capacity of the power supply. Then, according to the protection timer, there is provided a control means for causing the output control means to output a charging current until the charging time and for stopping the output of the output control means after the charging time elapses. apparatus. 2. A power source for charging, an output control means for controlling an output current of the power source, a battery charged by an output of the output control means, and a unique battery for identifying the type or capacity of the battery. A battery pack including an identification element having a physical quantity, a charging current detecting means for detecting a charging current or a part of the charging current flowing through the identification element, a protection timer for setting a charging time of the battery, and a charging timer at the start of charging. Calculating the capacity of the battery based on the result of the charging current detecting means, determining the charging current based on the battery capacity, setting the charging time in the protection timer based on the battery capacity and the charging current, A control means for causing the output control means to output the determined charging current until the charging time is reached according to a protection timer, and stopping the output of the output control means after the charging time elapses; A battery charger comprising: 3. The battery charger according to claim 1, wherein the power source is capable of controlling output capacity or output voltage. 4. The output control means is a switching means that turns on / off according to a control signal from the control means, and outputs the determined charging current by periodic on / off control during charging. The battery charging device according to claim 1, 2, or 3, wherein 5. The battery charging device includes drive means for generating a pulse width modulation signal having a pulse width according to a control signal from the control means, and the output control means includes pulse output from the drive means. 3. A switching means for turning on / off according to a width modulation signal, wherein the charging current determined by the on / off control of the pulse width modulation signal is output during charging. Three
The battery charger described. 6. The battery charging device has a voltage detection means for detecting the voltage of the battery, and the control means determines that the voltage of the battery is a fixed ratio of the rated voltage according to the detection result of the voltage detection means. 6. When it is determined that the voltage value has been reached, the protection timer is reset and reset for a predetermined time, and then supplementary charging is performed with a predetermined minute charging current. The battery charger described. 7. The battery charger according to claim 1, 2, 3, 4, 5 or 6, wherein the control means is a microcomputer.