JPH0667130B2 - Storage battery charger - Google Patents

Description

TECHNICAL FIELD The present invention relates to a storage battery charging device used in various relatively small electric devices such as an electric razor and a rechargeable portable electric light.

[Conventional technology]

Various charging control units for rechargeable batteries have been proposed, one of which is, for example, the charging time as disclosed in Japanese Patent Laid-Open No. 56-76176, and the power supply to the storage battery is stopped after a predetermined time. There is a so-called counter type control unit that does.

Since such a counter method uses a normal counter, the structure can be simplified without requiring strict accuracy.

However, since the counter is configured to be driven on the primary side of the inverter unit, that is, the commercial power supply voltage as it is, it is necessary to use a high withstand voltage type that can sufficiently withstand the commercial power supply voltage, which is expensive. There was a tendency.

Therefore, it has been proposed to provide a detection control unit on the secondary side of the inverter unit, that is, on the storage battery side (for example, Japanese Patent Laid-Open No.
(Refer to Japanese Laid-Open Patent Publication No. 137640) [Problems of the prior art] However, the above-mentioned conventional one obtains the driving power of the counter from the storage battery charged by the output of the secondary winding of the inverter unit, but The voltage between terminals fluctuates between the start and full charge, and the voltage between terminals is high at high temperature (40 ° C) in the charging environment such as low temperature charging.
Therefore, the stability of the driving power of the control unit is influenced by the characteristics of the storage battery and tends to be unstable.

Moreover, in a so-called 2-way electrical device that supplies electric power to a load such as a motor while charging, the impedance of the load such as the motor is generally smaller than the impedance of the counter. It depends, and it was by no means preferable.

[Means for solving problems]

The present invention has been made in view of the above points, and the rectifying units D ₂ and D ₃ for charging the storage battery B are provided on the same core wound with the primary winding N ₁ of the inverter 4 connected to the power supply. The secondary windings N ₃ and N _{4 provided with} are wound, and the switching element Tr ₂ for controlling the charging current is interposed between the secondary windings N ₃ and N ₄ and the storage battery B, and the output windings N ₅ for power supply for driving a counter for generating a control signal of the switching element Tr ₂ is wound around the same core, and an oscillation circuit unit including a primary winding N ₁ of the inverter 4, the secondary winding The output circuit section having the lines N ₃ and N ₄ and the output winding N ₅ is electrically separated from each other.

〔Example〕

 Embodiments will be described below with reference to the drawings.

The power plug 1 has a fuse 2 and a protective capacitor C ₁ ,
The bridge rectifier Ref is connected, and the coil L,
A low pass filter 3 for noise elimination, which is composed of a resistor R ₁ and a capacitor C _2, is connected.

An inverter 4 is connected to the low pass filter 3. This inverter 4 is composed of a bias resistor R ₂ , an adjusting trimmer R ₃ , a primary winding N ₁ , a feedback winding N ₂ , a capacitor C ₃ , a protective capacitor C ₄ , a protective thermistor TH and a diode D ₁ , and oscillates. It constitutes the circuit section.

Two secondary windings N ₃ and N ₄ are wound in opposite directions on the same core as the primary winding N _1, and diodes D ₂ and D ₃ are connected in series to form an output circuit section. . The cathode sides of the diodes D ₂ and D ₃ are connected to the + pole of the storage battery B and the motor M. The negative pole of the storage battery B is connected to the center contact a of the two-circuit one-contact switch SW, and the resistance R ₄
It is connected to a switching element Tr ₂ such as a transistor via. Another contact b, c of the two circuit-contact switches SW are respectively connected to the motor M and the secondary winding N _3, N _4.

The base side bias resistor R ₅ of the switching element Tr ₂ is connected to the motor side contact b of the two-circuit one-contact switch SW via the first charge display element LED ₁ such as a light emitting diode and the diode D ₄ . via a resistor R ₉ is connected to the output terminal 6 ₂ of the counter 6 described later. The positive side of the storage battery B is connected to the anode side of a _second charge termination display element LED ₂ such as a light emitting diode, and the cathode side of this charge termination display element LED ₂ is also connected to the output terminal 6 of the counter 6 which will be described later. Connected to ₂ .

Further, the output winding N ₅ is wound around the same core as the primary winding N _1, and constitutes the power supply circuit 5 together with the π-type filter composed of the diode D _{5, the} resistor R ₇ , and the capacitors C ₅ , C ₆ . Power is supplied to drive the counter 6,
The ground lines of the secondary windings N ₃ and N ₄ are connected to the ground line of the power supply circuit 5.

In this way, each winding of the output circuit having the secondary windings N ₃ and N ₄ for charging and the output winding N ₅ for the counter driving power supply is provided on the same core wound with the primary winding N ₁ of the oscillation circuit of the inverter 4. Although the wire is wound, the oscillator circuit section including the primary winding N ₁ to which a high voltage is applied and the secondary winding N ₃ and N ₄ output winding N to which a low voltage is applied
_The output circuit unit having ₅ is not connected to a ground line and is isolated and insulated in an electric circuit.

For this reason, external noise such as spikes that intrude from the power supply line on the primary side, which makes the counter 6 unstable, is difficult to be transmitted to the output winding N ₅ and the counter 6 on the secondary side, and malfunction and destruction can be suppressed. Since the electric circuit is separated, the entire low-voltage output circuit side can be separated from the high-voltage oscillation circuit side, and the safety can be improved.

In particular, the counter 6 on the output circuit side is converted to direct current, and the direct charging current flowing in the storage battery B is directly controlled by the switching element Tr ₂ , so that it is synchronized with the oscillation high frequency of the inverter on the oscillation circuit side. It is not necessary to perform precise control in combination, and it is possible to suppress the influence of changing the oscillation frequency, so that stable charge control can be performed.

The counter 6 has an input terminal 6 ₁ , an output terminal 6 ₂ and a CR oscillation terminal.
6 ₃ , ground terminal 6 ₄ , reset terminal 6 ₅ , stop terminal 6 ₆ ,
There is oscillating voltage supply terminal 6 _7, of which the reset terminal 6 ₅ and the input terminal 6 ₁ is connected to the output side of the power supply circuit 5, and the output terminal 6 ₂ stop pin 6 ₆ and the charging display device LED ₁ It is connected to the anode side and the cathode side of the charge completion display element LED ₂ , and is connected in the opposite direction to both display elements LED ₁ and LED ₂ . Is further connected the oscillation voltage supply terminal 6 ₇ to resistors R _8, CR oscillation pin 6 ₃ via a time constant circuit including a capacitor C _7. C ₈ is a constant voltage capacitor.

Next, the operation will be described.

When the switch SW is turned on, the electric current is supplied from the storage battery B to drive the motor M.

To charge the storage battery B, the switch SW is turned off and the power plug 1 is inserted into an outlet (not shown). Then, the inverter 4 starts oscillating, an output voltage is generated in each of the secondary side output windings N ₃ , N ₄ and N ₅ , and the voltage is supplied to the input terminal 6 ₁ of the counter 6 by the output of the power supply circuit 5. , the counter 6 output voltage of the power supply circuit 5 is an input to the reset terminal 6 ₅ reaches the control unit drivable predetermined voltage is reset, and starts counting the oscillation due to the capacitor C ₇ and the resistor R _8. At this time, the output terminal 6 ₂ is connected to the diodes D ₂ and D ₃
It is higher level than the cathode side of, the charging end display element LED ₂ does not light, the base current of the switching element Tr ₂ flows and the charging display element LED ₁ that displays the charging state lights and the switching element Tr 2 ₂ becomes conductive and storage battery B
Is charged.

Here, the output terminal 6 ₂ Wait for integrating a predetermined charging time becomes low level, the charging display element LED ₁ does not flow the base current of the switching element Tr ₂ is turned off, the switching element Tr ₂
Is cut off and charging is stopped. At the the end of charging the display element LED ₂ simultaneously lit current flows toward the output terminal 6 _2, notifying that charging has ended. In this way, when output appears in the output circuit section, counting is started,
When it counts to the set value the output terminal 6 ₂ becomes low level, it is possible to reliably turn off the charging display element LED _1.

Next, the case where the switch SW is connected in the charged state will be described.

The state of charge when the switch SW is in the off state is as described above. However, if the switch SW is connected in this state of charge, the commercial power supply is stepped down by the inverter 4 and the secondary windings N ₃ and N ₄ are directly connected. Will be used as the power source for the load, and this output current will not flow to the storage battery B, and the motor M as the load will
Is directly supplied to the motor M from the storage battery B.
Is supplied to.

This because, the storage battery B even though in a discharged state, the output terminal 6 ₂ of the counter 6 is kept at a high level, possibly erroneous display that in lit charge display element LED ₁ charging is performed is there.

In this circuit, in order to prevent this, the anode side of the charge display element LED ₁ is connected to the output terminal 6 ₂ via the current limiting resistor R ₉ and further the switch SW via the diode D _4.
Is connected in parallel to the terminal b.

Because of this, during charging when the counter 6 does not reach the predetermined value,
By connecting the switch SW, the output current from the output terminal 6 _2, via the charging display device LED ₁ so far, as indicated by the arrow P, and inflow and switch SW terminal b to the lower diode D ₄ side of potential Grounded.

In this way, while the switch SW is connected, the charge display element LED ₁ is not turned on, indicating that the charge is stopped.

The charge indicator LED ₁ is red and the charge indicator LED ₂
Is easy to distinguish if the emission color is different as green.
A buzzer or the like may be used as the charge display elements LED ₁ and LED ₂ .

〔The invention's effect〕

As described above, according to the present invention, the rectifiers D ₂ and D ₃ for charging the storage battery B are provided in the same core on which the primary winding N ₁ of the inverter 4 connected to the power source is wound. Secondary winding N ₃ ,
While N ₄ is wound, a switching element Tr ₂ for controlling a charging current is interposed between the secondary windings N ₃ and N ₄ and the storage battery B, and a control signal for the switching element Tr ₂ is generated. the output windings N ₅ for power supply for driving the counter is wound around the same core, and an oscillation circuit unit including a primary winding N ₁ of the inverter 4, the secondary winding N _3, N ₄ and an output winding The storage battery B is charged by the outputs of the secondary windings N ₃ and N ₄ of the inverter 4 because the output circuit section having N ₅ is electrically separated, but the counter 6 that controls the charging state of the storage battery B is charged. Is driven by another stable output winding for power supply, and reliable control can be performed without being affected by the storage battery B or the load M.

Moreover, since the oscillation circuit section and the output circuit section are separated from each other in terms of an electric circuit, it is highly safe even if the user's hands are separated from the load M such as a motor or the storage battery B on the output circuit side. Can be

In particular, the counter 6 on the output circuit side is converted to direct current, and since the direct charging current flowing in the storage battery B is directly controlled by the switching element Tr, it is synchronized with the oscillation high frequency of the inverter on the oscillation circuit side. It is not necessary to perform precise control, and it is possible to suppress the influence of changing the oscillation frequency, so that stable charge control can be performed.

[Brief description of drawings]

FIG. 1 shows an electric circuit diagram of an embodiment of the present invention. 4 ...... inverter, N ₁ ...... winding, B ...... battery, N _3, N
₄ …… Secondary winding, N ₅ …… Output winding, D ₂ , D ₃ …… Rectifier. Tr ₂ ...... Switching element

Claims (1)

[Claims] 1. A primary winding of an inverter 4 connected to a power supply.
Secondary windings N ₃ and N ₄ having rectifiers D ₂ and D ₃ for charging the storage battery B are wound around the same core around which N ₁ is wound, and
Between the secondary winding N _3, N ₄ and the storage battery B, is interposed switching element Tr ₂ which controls the charging current, the output of the power supply for driving a counter for generating a control signal of the switching element Tr ₂ An oscillating circuit portion having a winding N ₅ wound around the same core and including a primary winding N ₁ of the inverter 4, and secondary windings N ₃ and N ₄
A charging device for a storage battery, characterized in that the output circuit section having the output winding N ₅ and the output circuit section are separated in an electric circuit.