JP2000023386A - Charging circuit - Google Patents

Abstract

(57) Abstract: A first control unit for stepping down a commercial AC voltage to a charging voltage using an inverter circuit, and a charging voltage supplied from the first control unit to a secondary battery. In a charging circuit that detachably connects the second control unit 14 for applying the voltage via the electrode unit 15, a contact signal of the electrode unit 15 is caused without requiring a control signal line. Malfunction can be prevented beforehand. SOLUTION: While a second control unit 14 includes a charge control unit that detects a state of charge of a secondary battery 13 and limits charging when the secondary battery 13 is fully charged, a charge control unit in a first control unit 12 is configured to operate due to a decrease in charging current. When the load detecting means detects that the charging voltage has increased, the load detecting means performs an operation of limiting the power output from the inverter circuit 16.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a charging circuit for a secondary battery, and more particularly, to a charging circuit for converting a commercial AC voltage to a charging voltage and a small electric device for accommodating the secondary battery. The present invention relates to a device that is detachably provided via a power supply and that enables output control on the adapter side in accordance with the state of charge of the secondary battery.

[0002]

2. Description of the Related Art Conventionally, a charging circuit of this type has a two-stage structure for supplying a charging voltage from an adapter portion to a small electric device.
In general, one or a plurality of control lines for transferring control signals to each other are provided in addition to the power supply lines to perform a linked control operation between the two.

[0003]

However, in each of the above-described charging circuits, the charging control circuit previously configured as an integrated circuit is simply divided into two, so that a complicated control operation is performed. The more they try, the more electrodes are needed for the transfer of control signals.

On the other hand, in an electric device using a charging circuit of this type, an electrode portion of a connector is exposed to the outside like an electric shaver which can be washed with water, and insertion / removal is frequently repeated in a poor environment. In many cases, poor contact at the electrode portion causes malfunction. In particular, the control signal
Since the signal level is generally suppressed to a necessary minimum, the influence of the poor contact of the electrodes is large.

As a result of studying the above problem, the inventor of the present invention has found that when a means for restricting charging of a secondary battery is provided on either the charging adapter side or the electric device side having the secondary battery, Even if there is, the limiting state of charging by the limiting means appears as the magnitude of the charging current,
It has been found that a necessary control operation can be performed without providing a control line by actively using the charging current flowing through the electrode unit as control data.

[0006] The present invention has been made based on the above-mentioned findings, and the control state of charging the secondary battery is set to 2
An object of the present invention is to provide a charging circuit which does not need to transmit and receive a control signal through a control line by performing detection through a power supply line, and which has few malfunctions while maintaining a simple configuration.

[0007]

A charging circuit according to the present invention has a first control unit for stepping down a commercial AC voltage Vm to a predetermined charging voltage Vs as schematically shown in FIG. 12 and a second control unit 14 for applying the charging voltage Vs output from the first control unit 12 to the secondary battery 13, and both control units 12 and 14 via the electrode unit 15.
Is detachably connectable.

According to the present invention, when at least one of the first control unit 12 and the second control unit 14 satisfies a preset condition, charging of the secondary battery 13 can be restricted. Means for transmitting the information on the restriction state to the control unit not having the means for enabling the above-mentioned restriction by the magnitude of the charging current passed through the electrode unit 15. And

When the second control unit 14 satisfies a preset condition, charging of the secondary battery 13 can be limited, while the first control unit 12 is connected to the electrode unit 1.
5, the charging power supplied to the second control unit 14 can be limited in response to a decrease in the charging current supplied to the second control unit 14 via the control unit 5.

The first control unit 12 can limit charging power supplied to the second control unit 14 in response to satisfying a preset condition, while the second control unit 1
4 can be made to be able to charge the secondary battery 13 in accordance with the input timing of the charging voltage Vs which is not restricted by the first control unit 12.

The condition for limiting charging on the first control unit 12 side is the elapse of a set time, and the condition for limiting charging on the second control unit 14 side is that the secondary battery 13 This is performed by detecting that a predetermined physical characteristic such as a battery temperature or a terminal voltage that changes with charging exceeds a set value.

The first control unit 12 is capable of supplying a very small amount of electric power to the second control unit 14 even after the charging power is limited. After the charging of the first control unit 12 is restricted,
The limited state is maintained by the minute power supplied from the side.

Furthermore, the charging current supplied from the first control unit 12 to the second control unit 14 is pulsed output from the inverter circuit 16 and the first control unit 1
The charging power limiting operation corresponding to the reduction of the charging current on the second side can be configured to be performed by detecting a voltage change of the output voltage from the inverter circuit 16 smoothed by a capacitor.

[0014]

As described above, according to the present invention, the charge control information is transmitted according to the change of the charge current. Therefore, the overall structure can be simplified without the need for a control signal line. In addition to the above, it is possible to prevent malfunction due to poor contact of the electrodes.

[0015]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Hereinafter, the configuration of a charging circuit according to the present invention will be specifically described based on an example in which the charging circuit is applied to a portable small electric device illustrated in FIG. Here, the small electric device is an electric device main body 17 having a built-in secondary battery 13.
And a charging adapter 20 which is detachably connected to the electric device main body 17 via a predetermined electrode portion 15.

The electric circuit provided on the side of the adapter 20 is a rectifier circuit for performing full-wave rectification of a commercial AC voltage of 100 V AC or more input through a power plug 21 and converting it into a predetermined pulsating voltage. 22, an inverter circuit 16 for intermittently converting a high-voltage pulsating voltage to a low-voltage pulse voltage, an output control circuit 23 for limiting output power from the inverter circuit 16, and charging is started. Timer circuit 24 for starting the output limiting operation in output control circuit 23 in response to the elapse of the set time from
And a load detection circuit 25 for starting the limiting operation of the output control circuit 23 in response to the charging current supplied from the adapter 20 to the secondary battery 13 of the electric device main body 17 falling below the set value. It is composed of

On the other hand, the electric circuit provided in the electric device main body 17 detects the input of the charging voltage whose output power is not restricted from the charging adapter 20 and detects the input of the charging voltage to the secondary battery 13. A charge timing control circuit 27 for starting the application of a charge signal and a predetermined detection signal 28 when it is detected that the battery temperature rises above a set value and it is determined that the battery is fully charged.
When the detection signal 28 is output from the temperature detection circuit 29, the charge control signal 30 is sent to the charge timing control circuit 27 to forcibly stop the application of the charge voltage to the secondary battery 13. And a latch circuit 31 that maintains the stopped state irrespective of the presence / absence of the detection signal 28 so that the stopped state of the charging can be maintained until the battery is reset even if the battery temperature decreases due to the stop of the charging. Is done.

With the above configuration, the charging adapter 20
When a commercial AC voltage is supplied to the charging adapter 20 through the power plug 21 in a state where the electric device main body 17 is connected to the charging device 20 via the electrode portion 15, the inverter circuit 16 starts outputting the charging voltage. At this time, since the output control circuit 23 does not limit the output of the inverter circuit 16 at all, the charging adapter 20 supplies a charging voltage to which the output power is not limited to the electric device body 17. Then, on the electric device main body 17 side, the charging timing control circuit 27 determines that the charging timing is reached, and charging is started by applying the input charging voltage to the secondary battery 13.

Here, the timer circuit 24 of the adapter 20 starts measuring the charging time from the above-described charging start timing, and when the preset charging time has expired, the output control circuit 2
3 to send an output control signal 32 to instruct the inverter circuit 16 to limit the output.

This output limitation is caused, for example, by the inverter circuit 1
6 is performed by changing its operation mode from a continuous driving state to an intermittent driving state, and the charging current is reduced when the charging power is forcibly reduced or stopped. Through the electrical equipment body 17 side,
The charging of the secondary battery 13 is forcibly stopped or limited.

Next, before the timer circuit 24 of the adapter 20 detects the elapse of the set time, if the temperature detection circuit 29 of the electric equipment main body 17 detects the set temperature, the detected state is latched. Through the circuit 31 and the charging timing control circuit 27, the operation is performed in such a manner that the application of the charging voltage to the secondary battery 13 is forcibly stopped or limited. When charging is limited in this way, the battery temperature decreases, but the output state of the charge control signal 30 is maintained as it is by the latch circuit 31 and the limited charging state is maintained thereafter.

On the other hand, even if the charging current is greatly reduced by stopping or controlling the charging of the secondary battery 13 as described above, the inverter circuit 16 of the adapter 20 maintains a continuous oscillation operation. For this reason, the charging voltage, which has been maintained at a value slightly higher than the terminal voltage of the secondary battery 13 during charging, changes from 3 V to 7 with a decrease in the load current.
It changes greatly to about V.

When the load detecting circuit 25 detects the rise of the charging voltage, it outputs a reset signal 3 to the timer circuit 24.
3, the output control signal 32 is sent to the output control circuit 23 at the same time as the initialization, and the output of the inverter circuit 16 is limited by changing the oscillation of the inverter circuit 16 from the continuous state to the intermittent state.

In the limited state of the charging power, the secondary battery 13 cannot be normally charged with a large current, but is provided for various detection or control provided in the charging adapter 20 or the electric device body 17. Since the minimum power required to maintain the operation in each circuit is maintained, the above-described control state is maintained as it is.

However, when the full charge is detected by the temperature detection on the electric device main body 17 side, by removing the electric device main body 17 from the adapter 20, even the supply of the limited charging voltage 11 from the adapter 20 side is eliminated. Then, the latched state of the detection signal 28 in the latch circuit 31 is also released and returns to the above-mentioned initial state.

On the other hand, the timer circuit 24 on the adapter 20 side
In the case where the full charge detection and the charge limiting operation are performed in step (1), the load detection circuit 25 performs a detection operation substantially similar to that described above by removing the electric device body 17 from the adapter 20, and the timer circuit 24 Reset signal 3
3 is sent back to the initial state.

[0027]

DESCRIPTION OF THE PREFERRED EMBODIMENTS Hereinafter, the present invention will be described more specifically based on an example in which the present invention is applied to a water-washable electric shaver illustrated in FIGS. 3 to 6, but is not limited thereto. It is needless to say that the present invention can be carried out in substantially the same manner for various small electric devices provided with the battery 13. Note that the same or similar portions as those in the above-described embodiments are denoted by the same reference numerals, and redundant description will be omitted.

An electric razor embodying the present invention is shown in FIG.
A charging stand 34 can be interposed between the power supply and the charging adapter 20 as needed.

The electric device main body 17 includes an upper case 35 and a lower case 36, and an inner blade 37 provided in the upper case 35.
Is connected to a main switch 38 disposed in front of the lower case 36.
The motor 3 provided in the lower case 36 in conjunction with the ON operation of
This is substantially the same configuration as that of the related art that enables shaving with the outer cutter 40 by reciprocating or rotating by a driving means such as 9.

Next, the charging stand 34 is connected to the plug 4 provided at the tip of the output cord 41 extending from the charging adapter 20.
2 is a flat and substantially rectangular base 43 provided with a socket 11 to which the electronic device 2 is detachably connected, and a receiving portion on the upper surface side of the base 43 and into which the lower part of the electric device body 17 is removably fitted. 44.

The receiving portion 44 is a cylindrical body having an inner peripheral surface substantially the same as the lower end portion of the lower case 36 of the electric device main body 17 and having a substantially U-shaped cross section with an open upper portion.
5 is formed so that the lower end surface 46 on the side of the electric device main body 17 can be engaged, so that when the electric device main body 17 is inserted into the receiving portion 44, the bottom surface 45 of the receiving portion 44 and the lower portion of the electric device main body 17 When the end surface 46 is in close contact, the end surface 46 is electrically connected via the electrode portion 15.

The electrode portion 15 is a set of a positive electrode and a negative electrode for a charging voltage, and further includes a first electrode 18 provided on the electric device main body 17 side and a second electrode 19 provided on the charging stand 34 side. You.

Here, the first electrode 18 is connected to the electric device main body 17.
Of the positive electrode and the negative electrode are arranged so as to be substantially separated from each other. On the other hand, the second electrode 19 is connected to the bottom surface 45 of the receiving portion 44.
At the upper contact position with the first electrode 18, the electric device main body is made to protrude upward from the bottom surface 45 and is urged upward by a spring body (not shown) to the receiving portion 44. When the lower end of 17 is inserted, it is immersed in the bottom surface 45 so that the first and second electrodes 18 and 19 maintain a contact state at a predetermined contact pressure.

Next, the charging adapter 20 allows the plug blade 48 to protrude from the rectangular main body case 47 so as to be directly connectable to an outlet 49 provided on the wall surface and to connect the output cord 41 to the outside from the main body case 47. To be extended.

The commercial AC voltage input to the rectifier circuit 22 shown in FIG. 4 via the plug blade 48 is supplied to a protection circuit 52 including a temperature fuse 50 and a surge voltage absorbing element 51, a full-wave rectifier 53, and a filter. It is applied to the inverter circuit 16 via the circuit 54.

The inverter circuit 16 has substantially the same configuration as that of the prior art, and the current flowing through the primary coil 55 is regulated on and off by a switching element 56 such as a transistor, so that the inverter circuit 16 is wound around the same iron core as the primary coil 55 as shown in FIG. By extracting a pulse-like low voltage from the secondary coil 57 and the tertiary coil 58 indicated by the symbol corresponding to the time when the switching element 56 is turned off, a predetermined drive power is supplied to each section.

That is, while the ON timing of the switching element 56 is regulated by the feedback circuit 59 of the inverter circuit 16, the rise of the current flowing through the primary coil 55 is detected by the OFF timing regulating circuit 60 by the voltage across the resistor 61, and the set current is detected. The switching element 56 is rapidly turned off by grounding the control terminal 62 of the switching element 56 in response to the timing exceeding.

The output control circuit 23 for controlling the output from the inverter circuit 16 controls the oscillation period of the inverter circuit 16 by grounding the output control signal applied to the control terminal 62 of the switching element 56 with the transistor switch 63. It is done.

Further, when the commercial AC voltage input to the power supply voltage detecting circuit 64 provided in the rectifier circuit 22 exceeds 100 V, the period of the control is controlled by the voltage dividing resistor 65 and the Zener circuit. Detected by the diode 66, and the inverter circuit 16
, So that substantially the same output power can be obtained regardless of the difference between the input commercial AC voltage of 100 V and 250 V.

Further, the output control signal 32 output from the timer circuit 24 and the load detection circuit 25 shown in FIG. 5 is sent to the output control circuit 23 via the photocoupler 67 having the light emitting element 67a and the light receiving element 67b. The control mode can be changed from a continuous or nearly oscillating state of the inverter circuit 16 to a state in which the oscillation is normally stopped but the output power is limited by intermittently oscillating for a short time.

Here, the timer circuit 24 includes the tertiary coil 5
8 is further stabilized by a constant-voltage diode 68 and a large-capacity capacitor 69 as a drive voltage, counting is started from the start of application of the drive voltage, and a predetermined time elapses after finishing counting the set number. When it is determined that the driving voltage is high, the output control signal 32 of “H” level having a magnitude corresponding to the magnitude of the driving voltage is sent to the output control circuit 23 via the transistor 70 and the photocoupler 67 to force the inverter circuit 16 to operate. Performs output stop control.

When the inverter circuit 16 is stopped in this way, the output from the tertiary coil 58 is also stopped. However, since the power consumption by the timer circuit 24 is extremely small, the decrease in the drive voltage output from the drive power supply 92 is small, and The output control signal 32 output from the timer circuit 24 is held as it is.

On the other hand, when the output from the secondary coil 57 is stopped, the output from the driving power supply 93 decreases, the current supply to the photocoupler 67 decreases, and the light from the light emitting element 67a constituting the photocoupler 67 decreases. When the output decreases, the light receiving element 67b is turned off, the inverter circuit 16 resumes oscillation, and a pulse signal is output from the secondary coil 57.

Then, the large-capacity capacitor 69 is charged by the pulse signal, and the photocoupler 6 is charged in a very short time.
As a result, the output control signal is sent to the output control circuit 23, and the inverter circuit 16 is stopped again. In this way, by operating the inverter circuit 16 intermittently for a short period of time, a minimum power supply output required to maintain the operation of the timer circuit 24 is output by the inverter circuit 16.

On the other hand, the load detection circuit 25
7 is operated as a driving power source by stabilizing the output from the large-capacity capacitor 71. This voltage is applied to the electrode 1
5 is a pulse-like signal sent as a charging voltage to the electric device main body 17 through the capacitor 5, and is smoothed by the capacitor 71, but does not include a means for regulating the peak value. As a result, the voltage value fluctuates greatly.

Therefore, a voltage value of about 3 V, which is substantially equal to the terminal voltage of the secondary battery 13 when charging is performed on the electric device body 17 side, and increased when charging is stopped. A change in the voltage value of about 7 V is detected by the Zener diode 72, and a current is caused to flow through the resistor 73 in conjunction with the output voltage from the power supply provided for driving the load detection circuit 25 exceeding a set value. 7
By turning on 0, the output control signal 32 is sent to the output control circuit 23.

Further, when the voltage is detected by the load detection circuit 25, the resistance 7 is connected via the Zener diode 72.
4, a current also flows, and when the transistor 75 is turned on, the count value of the timer circuit 24 is reset.

Next, as shown in FIG. 6, the charging timing control circuit 27 provided in the electric equipment main body 17 converts the charging voltage inputted through the electrode 18 into the secondary battery 13 through the diode 76 and the overcurrent fuse 77. A transistor switch 78 connected in Darlington, and a switch contact 79 for regulating charging that is turned on and off in conjunction with the main switch 38 that regulates the timing of energizing the motor 39. I have.

With this configuration, when a charging voltage is applied to the electrode 18 during the off period of the main switch 38, the transistor switch 78 is turned on, and the secondary battery 13 is charged. However, the motor 39 stops because the battery capacity of the secondary battery 13 is extremely reduced, and even if the charging voltage is supplied from the adapter 20 to the electrode 18 while the main switch 38 is on, the transistor switch 7
The base end of the switch 8 is grounded by a switch contact 79 which is turned on in conjunction with the main switch 38, and the transistor switch 78 is forcibly turned off to prevent unnecessary charging.

The power for light emission is supplied by the charging voltage input from the electrode section 15, and the light emitting diode 8 is turned on by the transistor switch 78 of the charging timing control circuit 27.
A display circuit 81 that regulates the energization timing for 0;
The charging time for the secondary battery 13 can be displayed.

The temperature detecting circuit 29 uses, as a power source, a charge voltage input through the electrode 18 and stabilized by a diode 82 and a large-capacity capacitor 83, and is further disposed on the secondary battery 13 and at a reference position. The comparator 85 compares the voltages at both ends of the first and second thermistors 84a and 84b. If the difference between the two voltages exceeds a set value, the surface temperature of the secondary battery 13 exceeds the temperature at the time of full charge. The detection signal 28 is sent to the latch circuit 31.

When the detection signal 28 is output from the temperature detection circuit 29, the latch circuit 31 turns on the first transistor 86, and when the first transistor 86 is turned on, a current flows through the resistor 87 to turn on the second transistor 88. Turn on. Then, the voltage generated at both ends of the resistor 95 when the second transistor 88 is turned on turns on the third transistor 90 via the diode 89. As a result, the signal input side of the charging timing control circuit 27 is grounded, and the transistor switch 78 is turned off. Then, the charging of the secondary battery 13 is forcibly terminated.

At the same time, the voltage generated across the resistor 95 is applied to the first transistor 86 via the diode 91.
Of the first to third transistors 86 and irrespective of the presence or absence of the detection signal 28 thereafter.
The on / off states of 88 and 90 are maintained as they are, the transistor switch 78 of the charging timing control circuit 27 is kept off, and the charging of the secondary battery 13 is maintained in a stopped state.

The above-described latch circuit 31 is configured such that when the electric device main body 17 is removed from the charging stand 34, the input of the charging voltage via the electrode portion 15 is cut off, and the first
The ON state of the third transistors 86, 88 and 90 is also released, and the state automatically returns to the initial state.

In performing the full charge control of the secondary battery 13 on the side of the electric device main body 17, instead of or in addition to the above-described detection of the change in the surface temperature of the secondary battery 13, the charging time is changed. It is possible to detect the time of full charge, which has been conventionally proposed, such as a method of detecting a voltage at which the terminal voltage of the secondary battery 13 drops by a peak value or a predetermined voltage or a method of determining a charging time by a timer. Various methods can be employed.

Instead of providing the latch circuit 31 on the electric device main body 17 side to maintain the regulated state of the charging timing, the charging of the electric device main body 17 is stopped or restricted as described above, and the load is reduced. When the load detection circuit 25 detects that the load has become light, the output from the inverter circuit 16 is limited to a necessary minimum, and the limit state can be maintained by a latch circuit provided on the adapter 20 side. . In this case, the position where the latch circuit is interposed is not limited to the secondary side as well as the primary side of the inverter circuit 16 as long as the operation of the inverter circuit 16 can be limited.

Further, instead of performing the charging control state on the electric device main body 17 side by detecting a change in the charging voltage in the load detection circuit 25, a change in the load current flowing through the electrode section 15 is detected. It is also possible to know by doing. Further, the control circuit that uses the change in the charging current flowing through the electrode unit 15 as control information is not limited to the above-described one, and can be implemented by appropriately increasing or decreasing the number of control circuits. If a charging voltage can be generated, the inverter circuit 16
It goes without saying that any charging power source can be used instead of.

Further, a socket 11a having the same configuration as the socket 11 provided on the base 43 of the charging stand 34 is provided on the lower end surface 46 of the electric device main body 17 as shown in FIG. By connecting in parallel with
For example, when the user brings the device with him / her on a trip or the like, only the electric device body 17 and the charging adapter 20 need to be carried. In this case, the charging adapter 20 can be used without the charging stand 34.
The plug 42 is directly connected to the socket 11a of the electric device body 17.
, A charging current can be supplied directly from the charging adapter 20. In addition, the configuration of the electrode portion 15 that connects the electric device main body 17 and the charging adapter 20 is not limited to the above-described configuration, and can be appropriately changed and implemented.

As described above, instead of or in addition to supplying the charging voltage from the charging adapter 20 for stepping down the commercial AC voltage, as shown in FIG.
4 can be used as a charging power source. in this case,
The solar cell panel 94 can be provided alone, or can be swingably provided at an appropriate position such as the back side of the charging stand 34.

[Brief description of the drawings]

FIG. 1 is a schematic diagram showing a basic configuration of the present invention.

FIG. 2 is a block diagram showing an overall configuration of a charging circuit according to the present invention.

FIG. 3 is a perspective view showing an example in which the present invention is applied to an electric shaver.

FIG. 4 is an electric circuit diagram specifically showing a circuit configuration of an output portion provided in the charging adapter.

FIG. 5 is an electric circuit diagram specifically showing a circuit configuration of a control portion provided in the charging adapter.

FIG. 6 is an electric circuit diagram specifically showing a configuration of each circuit provided in the electric device main body.

FIG. 7 is a perspective view showing another embodiment of the present invention.

[Explanation of symbols]

 12 First control unit 13 Secondary battery 14 Second control unit 15 Electrode unit 16 Inverter circuit 17 Electric equipment body 18 First electrode 19 Second electrode 20 Charging adapter 21 Power plug 22 Rectifier circuit 23 Output control circuit 24 Timer circuit 25 Load detection circuit 27 Charge timing control circuit 28 Detection signal 29 Temperature detection circuit 30 Charging control signal 31 Latch circuit 32 Output control signal 33 Reset signal 34 Charging stand 38 Main switch 41 Output code 42 Plug 43 Base 44 Receiver 45 Bottom 46 Lower End face 52 Protection circuit 53 Full-wave rectifier 54 Filter circuit 55 Primary coil 56 Switching element 57 Secondary coil 58 Tertiary coil 60 Off time regulation circuit 63 Transistor switch 64 Power supply voltage detection circuit 67 Photocoupler 68 Constant voltage diode 78 Transistor switch 79 Switch contact 80 Light emitting diode 81 Display circuit 85 Comparator 86 First transistor 88 Second transistor 90 Third transistor 94 Solar panel

Claims (7)

[Claims] A first controller configured to reduce a commercial AC voltage to a predetermined charging voltage; and a second controller configured to apply a charging voltage output from the first controller to a secondary battery. A second control unit (14) and a charging circuit capable of being detachably connected to each other via an electrode unit (15), wherein at least the first control unit (12) and the second control unit (14) On the other hand, while a means is provided for enabling charging of the secondary battery (13) to be limited when a preset condition is satisfied, information on the limited state is controlled by a control not provided with the means for enabling the above-described limitation. To the electrode (1
5) A charging circuit for transmitting the charging current according to the magnitude of the charging current passed through the charging circuit. 2. The second control section (14) enables charging of the secondary battery (13) to be restricted when a predetermined condition is satisfied, while the first control section (12) Electrode part (1
The charging according to claim 1, wherein the charging power supplied to the second control unit (14) can be limited in response to a decrease in the charging current supplied to the second control unit (14) via (5). circuit. 3. The first control unit (12) responds to a condition that is set in advance to satisfy a second control unit (1).
While the charging power to be supplied to 4) can be limited, the second control unit (14) described above responds to the input timing of the charging voltage that is not limited by the first control unit (12). The charging circuit according to claim 1, wherein charging of the secondary battery is enabled. 4. The condition for limiting charging on the first control unit (12) side is the lapse of a set time, and the condition for limiting charging on the second control unit (14) side is: 4. The charging circuit according to claim 3, wherein the detection is performed by detecting that a predetermined physical characteristic of the secondary battery that changes with charging exceeds a set value. 5. The first control section (12) is capable of supplying a very small amount of power to the second control section (14) even after the charging power is limited. The charging circuit according to claim 4, wherein (14) maintains the limited state by the small amount of power supplied from the first control unit (12) even after charging of the secondary battery (13) is limited. 6. The charging current supplied from the first control unit (12) to the second control unit (14) is a pulse-like output from the inverter circuit (16), 6. The charging circuit according to claim 5, wherein the operation of limiting the charging power corresponding to the reduction of the charging current on the part (12) side is performed by detecting a change in the output voltage from the inverter circuit (16). 7. A solar cell is connected to the second control section (14) via an electrode section instead of the first control section (12), and an output voltage from the solar cell is a charging voltage. The charging circuit according to claim 3, wherein the charging circuit is supplied to the secondary battery (13).