JPH0756586Y2 - Charger - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention will be described in the following order.

A Industrial field of use B Outline of the device C Conventional technology (Fig. 2) D Problems to be solved by the device (Fig. 2) E Means for solving the problems (Fig. 1) F Action ( Fig. 1) G Example (Fig. 1) H Effect of the invention A Industrial field of application The present invention relates to a charging device, for example, charging a plurality of nickel-cadmium (Ni-Cd) storage batteries used in a video camera or the like. It is suitable to be applied to a charging device made in this way.

B Outline of the Invention The present invention relates to a charging device that sequentially charges a plurality of mounted secondary batteries, and a main power supply that supplies a charging current having a first current value to the secondary battery and a second current value. The sub-power supply that supplies the charging current of
The charging current having the first current value is supplied to the selected secondary battery, and the first current value for the selected secondary battery is detected when a predetermined drop in the voltage of the selected secondary battery is detected. By stopping the supply of the charging current, it is possible to realize a charging device capable of preventing the malfunction of quick charging due to a user's erroneous operation.

C Conventional technology Nickel-cadmium (Ni
-Cd) A storage battery (Nitsukado battery) can be charged rapidly in a short time of about 1 hour. Generally, a charging device for charging a Nitsukado battery of this type requires that the terminal voltage of the Nitsukado battery first reaches the peak voltage. Drop voltage (-ΔV)
The battery is rapidly charged with a current value of about 1 C (so-called 1-hour rate) until the detection of (1) (Japanese Patent Publication No. 59-37654).

Furthermore, in practice, this quick charge cannot charge the nickel-cadmium battery to the state of full charge, so the charging device has a current value of about 0.1 C (10-hour rate) for the following predetermined period, It is designed to perform a charging state (so-called trickle charging).

Conventionally, as this charging device, for example, as shown in FIG.
A battery is used in which the nickel-cadmium battery in a roll is automatically switched to perform rapid charging one roll at a time.

That is, in this charging device 1, reference numeral 2 denotes a power supply circuit unit as a whole, for example, a commercial power supply 3 is rectified, and a constant DC current required for rapid charging is output from the positive terminal 2a and the negative terminal 2b via the output resistance RS. I _S is supplied to the charging circuit unit 4.

In this charging circuit unit 4, the direct current I _S is
Is supplied to the emitters of PNP transistors Q1 and Q2, for example, which are elements forming the switch circuit.

The collectors of the transistors Q1 and Q2 are connected to the positive side electrodes 5Aa and 5A of the first and second battery holders 5A and 5B via the first and second diodes D1 and D2 for backflow prevention, respectively.
The negative electrodes 5Ab and 5Bb connected to Ba are connected to the negative electrode end 2b of the power supply circuit unit 2.

The transistors Q1 and Q2 are on / off controlled by the first and second control voltages V _CNT1 and V _CNT2 applied to the respective bases from the system controller 7, and the first and second battery holders 5A and 5B. With the first and second nickel-cadmium batteries 6A and 6B attached to the transistor Q1
Or when Q2 is in the ON state, the first or second nickel-cadmium battery
A direct current I _S is supplied to 6A or 6B to perform quick charging.

Further, first and second resistors R1 and R2 are connected in parallel between the emitters and collectors of the transistors Q1 and Q2, respectively. The resistance values of the first and second resistors R1 and R2 are such that when the transistors Q1 and Q2 are in the off state, a trickle current having a current value of about 1/10 of the direct current I _S It is designed so that it can be supplied to the nickel-cadmium battery 6A or 6B.

Here, the system controller 7 causes the voltage drop ΔV ₁ after the peak voltage of the first and second nickel-cadmium batteries 6A and 6B is reached from the positive electrodes 5Aa and 5Ba of the first and second battery holders 5A and 5B, respectively. It is designed to detect ΔV ₂ .

In this configuration, the first and second nickel-cadmium batteries 6A and
When the battery 6B is attached to the first and second battery holders 5A and 5B, respectively, the charging device 1 will be installed in the respective nickel battery 6A and 5B.
6B is first precharged by the trickle current obtained via the resistors R1 and R2.

In this state, when the system controller 7 detects that the nickel-cadmium batteries 6A and 6B have been precharged for a predetermined amount, the system controller 7 turns on the transistor Q1 by the first control voltage V _CNT1. Thus, the direct current I _S is supplied to the first nickel-cadmium battery 6A to start the rapid charging.

Then, the system controller 7 is the first nickel-cadmium battery.
When the drop voltage ΔV ₁ after the peak voltage is reached is detected at 6A, the transistor Q1 is turned off by the first control voltage V _CNT1, and the trickle current by the trickle current is applied to the first nickel-cadmium battery 6A. Start.

The system controller 7 also receives the second control voltage.
The V _CNT2 controls the ON state of the transistor Q2, which supplies the direct current I _S to the second nickel-cadmium battery 6B to start the rapid charging.

In this way, in the charging device 1, the first and second nickel-cadmium batteries 6A and 6B are sequentially switched so that the two batteries can be charged to the fully charged state.

In this power supply circuit section 2, the commercial power supply 3 is input to the primary rectifier circuit 8, and the positive and negative rectified outputs of the commercial power supply 3 are connected through a smoothing capacitor C1 in parallel to the positive coil of the primary coil of the power transformer 9. It is input to the side end and the negative side end.

A secondary current obtained from the positive side end and the negative side end of the secondary coil of the power transformer 9 is a rectifying diode DS inserted in series at the positive side end and a smoothing capacitor C2 connected in parallel.
Is rectified through the secondary rectifying circuit 10 and thus the direct current I _S required for rapid charging is output through the output resistance RS of the positive terminal 2a and the negative terminal 2b of the power supply circuit 2.

Further, a FET composed of a gate circuit is provided at the negative end of the primary coil.
(Field effect transistor) element Q3 is provided, and part of the output current I _S is input to its gate
A control pulse V _PWM from a PWM (pulse width modulation) control circuit 11 is given.

Thus, the PWM control circuit 9 sends the control pulse V _PWM so that the output current I _S always becomes a constant current value, and the FET element Q3
For example, the conduction width is variably controlled, whereby the power supply circuit section 2 constitutes a switching regulator circuit as a whole and the direct current I _S which is always a constant current can be supplied to the charging circuit section 4. It is done like this.

D Problem to be Solved by the Invention By the way, in the charging device 1 having such a configuration, when the transistor Q1 or Q2 is in the ON state, the current for rapid charging supplied to the first and second nickel-cadmium batteries 6A or 6B and , When the transistor Q1 or Q2 is in an off state, the first and second nickel-cadmium batteries 6A or 6A via the first and second resistors R1 and R2.
The trickle charging current supplied to 6B and the trickle charging current are both obtained by shunting the direct current I _S controlled to a constant current value.

Therefore, as described above, the trickle current supplied to the second nickel-cadmium battery 6B is changed by the trickle charging of the second nickel-cadmium battery 6B while the first nickel-cadmium battery 6A is being rapidly charged. Change, the first Nitsukado battery
The fast charge current supplied to 6A fluctuates.

From this phenomenon, in practice, for example, when the user mounts the nickel-cadmium battery 6A only on the first battery holder 5A and fast-charges it while mounting the nickel-cadmium battery 6B on the second battery holder 5B,
If the system controller 7 detects this as the voltage drop ΔV ₁ after the peak voltage is reached, the rapid charging current of the first nickel-cadmium battery 6A is stopped. It causes malfunction.

That is, first of all, only the first battery holder 5A is provided with a nickel battery.
The current I ₁ flowing in the first nickel-cadmium battery 6A during the fast charging with 6A attached is expressed by the following equation, I ₁ = I _S = α (α is a constant value) (1) , A direct charging current having a current value α equal to the direct current I _S is supplied, and the current I ₂ flowing in the second battery holder 5B is expressed by the following equation, I ₂ = 0 ... (2)

In this state, when the user mounts the second nickel-cadmium battery 6B on the second battery holder 5B, the current I ₂ flowing through the second battery holder 5B is The trickle current is expressed as follows, and as a result, the current I ₁ flowing through the first nickel-cadmium battery 6A during rapid charging is (3)
The trickle current represented by the formula decreases, and the voltage decrease due to the trickle current is detected by the system controller 7 as a voltage drop ΔV ₁ after the peak voltage is reached. Thus, the first nickel-cadmium battery 6A is being rapidly charged. Nevertheless, the malfunction of stopping this quick charge occurs.

In order to solve this problem, firstly, during quick charging of one nickel-cadmium battery, a method of controlling so that trickle current does not flow to the other, secondly, based on the detection voltage by the system controller, Accordingly, a method of correcting the rapid charging current for the nickel-cadmium battery during rapid charging may be considered.

However, in such a case, there is a problem that the circuit scale becomes complicated, and further, in the first method, there is a problem that the charging time for the nickel-cadmium battery for a plurality of turns is lengthened, and as a result, a solution is still insufficient. Atsuta

The present invention has been made in view of the above points, and proposes a charging device having a simple circuit configuration of the same scale as the conventional one and capable of preventing malfunctions when sequentially charging a plurality of windings of a nickel battery. It is a thing.

E Means for Solving the Problems In order to solve such problems, the present invention provides a charging device for sequentially charging a plurality of mounted secondary batteries 6A, 6B. A main power supply 21 that supplies a charging current I _S20 to each of 6B at a first current value, and a first current by selectively connecting the main power supply 21 to a plurality of rechargeable batteries 6A and 6B. The charging current I _S20 of the _specified value is supplied to the selected secondary batteries 6A and 6B, and the selected secondary battery is
The control means 7 for stopping the supply of the charging current I _{S20 having} the first current value to the secondary batteries 6A, 6B when a predetermined drop in the voltage of 6A, 6B is detected is provided in parallel with the main power supply 21. , And a secondary power source 21 for supplying a charging current I _T20 at a second current value lower than the first current value to the plurality of windings of the secondary batteries 6A and 6B.

F action The main power supply 21 that supplies the charging current I _S20 of the first current value to the secondary batteries 6A and 6B, respectively, and the sub power supply that supplies the charging current I _T20 of the second current value to the secondary batteries 6A and 6B, respectively. A power supply 21 is provided in parallel to supply the charging current I _S20 having the first current value to the selected secondary batteries 6A and 6B, and also to the selected secondary batteries 6A and 6B.
When a predetermined voltage drop is detected on the secondary battery 6A,
By stopping the supply of the charging current I _{S20 having} the first current value to 6B, the first and second charging currents I _S20 and I S that are always stable with respect to the selected secondary batteries 6A and 6B. _T20
Can be supplied.

G Embodiment Hereinafter, an embodiment of the present invention will be described in detail with reference to the drawings.

In FIG. 1 in which parts corresponding to those in FIG. 2 are designated by the same reference numerals, 20 indicates a charging device as a whole, and a power supply circuit section 21.
Is the first positive terminal of the main power source through the output resistor RS.
Constant DC current I required for rapid charging from 21a and negative terminal 21b
_S20 is supplied to the charging circuit section 22 and also used as a sub power source
The current obtained from the connection midpoint of the rectifying diode DS and the output resistance RS of the next rectifying circuit 10 is supplied from the second positive electrode end 21c and the negative electrode end 21b to the charging circuit unit 22 as the trickle current I _T20 necessary for trickle charging. Supply.

That is, in the charging circuit section 22, the direct current I _S20 is supplied to the emitters of the transistors Q1 and Q2, and the collectors of the emitters of the first and second diodes D1 and D2 for preventing backflow.
Through the first and second battery holders 5A and 5B, respectively.
Of the positive electrodes 5Aa and 5Ba.

Further, the transistors Q1 and Q2 are the first ones provided to the respective bases from the system controller 7 as in the conventional case.
And the second control voltages V _CNT1 and V _CNT2 are turned on and off, and the first and second battery holders 5A and 5B are loaded with the first and second nickel-cadmium batteries 6A and 6B, respectively. Alternatively, when Q2 is in the ON state, the direct current I _S20 is supplied to the first or second nickel-cadmium battery 6A or 6B to perform quick charging.

Furthermore, with the respective collectors of the transistors Q1 and Q2,
At the connection midpoint between the first and second diodes D1 and D2, the trickle current is supplied from the second positive terminal 21c of the power supply circuit section 21 via the first and second resistors R1 and R2, respectively. I _T20
Is being supplied.

The resistance values of the first and second resistors R1 and R2 are such that when the transistors Q1 and Q2 are in the off state, the trickle current I _T20 is a current having a current value about 1/10 of the DC current I _S20. It is selected as a value that can be supplied to the second nickel-cadmium battery 6A or 6B.

In the case of this embodiment, the power supply circuit section 21 has a switching regulator circuit configuration as a whole, and the first positive terminal
The direct current I _S20 sent from 21a can always be maintained at a constant current value.

That is, in the power supply circuit section 21, the first positive electrode end 21a
And the negative terminal 21b are connected by a series connection circuit of two voltage dividing resistors R20 and R21, and the first voltage dividing resistor R20 and R21 are connected.
The voltage obtained from the connection midpoint a is input to the non-inverting input terminal of the voltage fluctuation detection comparison circuit 23.

In addition to this, the rectifying diode of the secondary rectifying circuit 10
Between the connection midpoint between DS and the output resistance RS and the negative terminal 21b,
The voltage is obtained by connecting the zener diode ZD and the resistor R22 in series, and the voltage obtained from the second connection midpoint b of the zener diode ZD and the resistor R22 is input to the inverting input terminal of the voltage fluctuation detection comparison circuit 23. There is.

Further, at the output terminal of the voltage fluctuation detection comparison circuit 23, the light emitting diode of the photocatalyst 24 connected from the midpoint of the connection between the rectifying diode DS and the output resistor RS of the secondary rectifier circuit 10 via the driving resistor RPD. One end of the LED is connected.

Further, the detection current I _P obtained from the phototransistor PT of the photocatcher 24 is sent to the PWM control circuit 11, and thus the PWM control circuit 11 causes the DC current I _P flowing through the output resistor RS to be detected.
_The control pulse V _PWM is sent so that _S20 is always constant, and the conduction width of the FET element Q3 is variably controlled.

Thus, in the power supply circuit section 21, for example, when the direct current I _S20 flowing through the output resistance RS increases, the first positive terminal
The amount of voltage drop at 21a increases, and the potential at the first connection midpoint a drops below the potential at the second connection midpoint b.

As a result, the potential at the output end of the voltage fluctuation detection comparison circuit 23 decreases, and as a result, the drive current I _D of the light emitting diode LED increases and the amount of emitted light increases, and the detection current I _{P of the} phototransistor PT of the photocathode 24 increases. To do.

Therefore, the PWM control circuit 11 reduces the DC current I _S20 flowing through the output resistor RS by sending the control pulse V _PWM that reduces the conduction width of the FET element Q3, and in this way, the DC current I _S20. Is always controlled to a constant current value.

In the above configuration, when the first and second nickel-cadmium batteries 6A and 6B are attached to the first and second battery holders 5A and 5B, respectively, the charging device 20 operates as the first and second nickel-cadmium batteries.
First, 6A and 6B are precharged by the trickle current I _T20 obtained via the resistors R1 and R2.

In this state, when the system controller 7 detects that the first and second nickel-cadmium batteries 6A and 6B have been precharged for a predetermined amount, the system controller 7 turns on the transistor Q1 by the first control voltage V _CNT1. As a result, the direct current I _S20 is supplied to the first nickel-cadmium battery 6A to start rapid charging.

Subsequently, when the system controller 7 detects the drop voltage ΔV ₂₁ after the peak voltage is reached, it turns off the transistor Q1 by the first control voltage V _CNT1 . This causes the trickle current to the first nickel-cadmium battery 6A. The trickle charge by I _T20 is started, and the transistor Q2 is turned on by the second control voltage V _CNT2 , thereby supplying the direct current I _S20 to the second nickel-cadmium battery 6B to start the rapid charge. .

In this way, in the charging device 20, the first and second nickel-cadmium batteries 6A and 6B are sequentially switched so that both the two batteries can be charged to the fully charged state.

Further, in the charging device 20, the direct current I _S20 required for quick charging and the trickle current I _T20 required for trickle charging are separately supplied to the first and second nickel-cadmium batteries, and required for rapid charging. Since the DC current I _S20 is always maintained at a constant current value, for example, the first
It is designed so that malfunctions that occur when the nickel-cadmium battery 6A is mounted on the second battery holder 5B during rapid charging by mounting the nickel-cadmium battery 6A only on the battery holder 5A of FIG.

That is, in this charging device 20, first, while the nickel-cadmium battery 6A is attached only to the first battery holder 5A, during rapid charging,
The current I ₂₁ flowing through the first nickel-cadmium battery 6A has a current value α equal to the direct current I _S20 as expressed by the following equation, I ₂₁ = I _S20 = α (α is a constant value) (4). The rapid charging current is supplied and the current I ₂₂ flowing through the second battery holder 5B is given by the following equation, I ₂₂ = 0 (5), because the battery holder 5B itself is opened.

In this state, when the user mounts the second nickel-cadmium battery 6B on the second battery holder 5B, the current I ₂₂ flowing through the second battery holder 5B is Although the trickle current is supplied represented in practically transistor Q2 because the off state, the current I ₂₁ flowing in the first Nitsukado battery 6A during fast charge, adapted to maintain a constant current value Therefore, even if such an erroneous operation is performed by the user, the two volumes of the first and second nickel-cadmium batteries 6A and 6B can be sequentially and rapidly charged normally.

According to the above configuration, the quick charging current and the trickle charging current are separately supplied to the two-volume nickel-cadmium batteries, so that the trickle charging current of the other nickel-cadmium battery can be maintained during the rapid charging of the one nickel-cadmium battery. Even if the value fluctuates, it is possible to effectively avoid the fluctuation of the quick charging current for the nickel-cadmium battery during the rapid charging. It is possible to realize a charging device that can be prevented in advance.

In addition, in the above-mentioned embodiment, the case of rapidly charging two-volume nickel-cadmium battery was described, but the present invention is not limited to this, and the nickel-cadmium battery may have three or more windings. In this case, in the charging device 20, the transistor Q1 is used. , A trickle current resistor R1, a backflow prevention diode D1, and a battery holder 5A, which has the same structure as the charging circuit for one turn of the nickel battery,
It may be configured such that the required number of turns are connected in parallel and the system controller sequentially controls switching.

Further, in the above-mentioned embodiment, the primary side of the power transformer is
Although the power supply circuit unit 21 of the switching regulator circuit configuration that switches by the FET element is used, the present invention is not limited to this, and the point is that if the rapid charging current is always kept constant, other Even if the power supply circuit having the configuration is used, the same effect as that of the above-described embodiment can be realized.

Furthermore, in the above-described embodiment, the case where a nickel-cadmium (Ni-Cd) storage battery is used as the rechargeable secondary battery is described, but the present invention is not limited to this, and another rechargeable secondary battery is used. Is widely applied to a charging device that sequentially charges a plurality of windings.

H Effect of the Invention As described above, according to the present invention, in a charging device for sequentially charging a plurality of mounted secondary batteries, a main power source for supplying a charging current having a first current value to the secondary batteries is used. , Second
A sub-power supply for supplying the charging current having the current value of 2 to each of the secondary batteries is provided in parallel to supply the charging current having the first current value to the selected secondary battery and the voltage of the selected secondary battery. By stopping the supply of the charging current having the first current value to the secondary battery when a predetermined drop is detected, the first and second stable secondary batteries are always stable for the selected secondary battery. Therefore, it is possible to realize a charging device that can prevent the malfunction of quick charging due to a user's erroneous operation with a simple circuit configuration that is almost the same as the conventional one.

[Brief description of drawings]

FIG. 1 is a connection diagram showing an embodiment of the present invention, and FIG. 2 is a connection diagram showing a conventional charging device. 1, 20 ... charging device, 2, 21 ... power supply circuit section, 3 ... power supply, 4, 22 ... charging circuit section, 6A, 6B ... nickel battery
I _S , I _S20 …… Rapid charge current, I _T20 …… Trickle charge current.

Claims (1)

[Scope of utility model registration request] 1. A charging device for sequentially charging a plurality of mounted secondary batteries, comprising: a main power supply for supplying a charging current to each of the plurality of secondary batteries at a first current value; The charging current having the first current value is supplied to the selected secondary battery by selectively connecting a power source to the plurality of windings of the secondary battery, and the selected secondary battery is also supplied.
Control means for stopping the supply of the charging current having the first current value to the secondary battery when a predetermined drop in the voltage of the secondary battery is detected; A charging device, comprising: a sub-power supply that supplies a charging current with a second current value lower than the first current value to the secondary battery.