JP2803872B2 - Charging circuit - Google Patents

Description

Description: TECHNICAL FIELD The present invention relates to a charging circuit that controls charging of a storage battery and can drive a load such as a motor, for example.

[Conventional technology]

Heretofore, a rechargeable NiCd battery has been used in a small and lightweight shaving apparatus or the like in order to ensure repeated use or use without an AC power supply. This battery is designed to be charged by, for example, a charger using a ringing choke converter, and a battery that directly drives a load by an AC drive function by switching a switch and a high-speed charge by a charge control function has been developed. .

 Such a conventional charging circuit is shown in FIG.

After the alternating current from the AC power source which is full-wave rectified by the rectifier circuit Ref, it flows through the resistor R _5, thereby the transistor Q ₁ is turned on. By turning on the transistor Q _1, the rectification current flows through the primary coil L ₁ of the transformer T, to increase the voltage of the resistor R _7. As a result, the transistor Q ₂ is turned on, turning off transistor Q _1. At this time, been induced voltage in the output coil L ₂ by electromagnetic energy accumulated in the primary coil L _1, 2-order current is generated, to charge battery B. Timer
IC10 is to turn on the transistor Q ₃ and a high on the output terminal P _O to elapse of a predetermined time, it stops the charging operation.

Switch SW _A is turned on to drive the motor M which is a load, intended for turning off is Setsu換Ru those with interlock switch SW _B, and SW _C. In the illustrated state, charging of the battery has been performed, whereas when the switch SW _A is turned on, the switch SW _B is turned on, the switch SW _C is connected to the output terminal P _O side of the timer IC 10. Then, when driving the motor M, resistance parallel circuit of R ₆ and the resistor R ₇ to delay the turn-on time transistor Q ₂ with increasing the secondary current, the output terminal P _O timer IC10
Is forcibly kept low to prevent charging control.

4 is a diagram showing a slide switch of the above switch SW _A to SW _C.

In FIG. 3A, the slide switch has four contacts.
An elastic slide arm 20 having P _{A to} P _D (to improve the contact with the following pieces S _{A to} S _E ), and the slide arm 20
_A small and inexpensive one is used, which is composed of 20 pieces of contact pieces S _{A to} S _E arranged opposite to the above-mentioned respective contacts. In addition,
Contact piece S _D is connected to the ground of the circuit at the common terminal, the contact piece S _E is connected to the transistor Q ₄ for counting the operation control of the timer IC 10.

Then, as shown in FIG.
The motor M can be switched on by a simple operation such that the motor M is turned on while being slid to the SW _ON position, and only the storage battery B is charged while being slid to the SW _OFF position.

[Problems to be solved by the invention]

By the way, in order to stop the control of the motor M (or switch to charging) from the motor-on state where the slide arm 20 is slid to the SW _ON position,
When sliding the 20 to SW _OFF side, the elasticity of the slide arms 20 (the contact pressure between the contact piece S _D and the contact P _D), or the contact piece S _D,
Contact P _D due to dust or the like adhering to the contact P _D other contacts
Was sometimes separated from the contact piece _SD even momentarily. Then, due to the instantaneous separation between the contact point P _D and the contact piece _SD , the large load current flowing through the motor M loses its place to go and flows into the output terminal P _O of the timer IC 10 having the lowest impedance. As a result, there is a problem that the timer IC 10 is destroyed.

The present invention has been made in view of the above, and an object thereof is to provide a charging circuit 9 never contact P _D destroys the timer IC spaced from the contact piece S _D.

[Means for solving the problem]

The present invention is a charging circuit for charging a storage battery by charging control and supplying power from the storage battery to a load, wherein the charging circuit includes at least one arm having at least three contacts, and each arm having at least three contacts. Three independent slidable contacts are a first contact for turning the load on and off, and a second contact connected to the output terminal of the timer IC for charge control when the load is on. A charging circuit having an interlocking slide switch comprising a third contact piece for constantly connecting the arm to ground, wherein a constant voltage element is connected between the output terminal of the timer IC and ground. .

In a charging circuit for charging a storage battery by charging control and supplying power from the storage battery to a load, one arm having three contacts and an independent slidable relative to each contact of the one arm. A first contact for turning on and off the load, a second contact for connecting the output end of the timer IC for charge control to ground when the load is on, An interlocking slide switch composed of a third contact piece for constantly connecting the arm portion to the ground, and a semiconductor element extending forward from the output end of the timer IC toward the second contact piece are provided. Things.

[Action]

According to the present invention, when one contact of the arm is separated from the third contact piece for connecting to the ground when the load is turned on,
The load current flowing from the load into the arm via the first contact piece flows into the constant current element, where the current and voltage are controlled, and the current flowing into the output terminal of the timer IC is suppressed.

According to the second aspect of the present invention, when one contact of the arm is separated from the third contact for connecting to the ground when the load is turned on, the load flows from the load to the arm via the first contact. The load current to be supplied is blocked from flowing into the timer IC by the semiconductor element. The load current is consumed by other parts or the motor itself.

〔Example〕

FIG. 1 is a charging circuit showing a first embodiment of the present invention. FIG. 3 is a waveform diagram of a main part.

The figure shows a ringing choke converter type charging circuit.

AC current from AC power supply AC such as commercial power supply is
The primary coil L _{1 of the} transformer T is full-wave rectified and stepped down by f
It is led to. Some of the rectified current is adapted to be guided through a resistor R ₅ to the base of the transistor Q _1.

The transistors Q ₁ and Q ₂ , the resistors R ₆ and R ₇ , the capacitor C ₂ and the feedback coil L ₃ constitute a circuit for turning on and off the current flowing into the transformer T.

In addition to rectifying diode D ₂ of the secondary to the side output coil L ₂ of the transformer T, load such as a motor M connected in parallel to the battery B and battery are connected.

The peripheral circuit including the timer IC 10 and the transistors Q ₃ and Q ₄ constitutes a charge control circuit that switches the charging operation from on to off in anticipation of the time when the storage battery B reaches full charge.
The resistor R ₁ , the capacitor C _1, and the Zener diode D ₁ are a constant voltage generator serving as a power supply of the timer IC 10. Resistor R ₄ and the capacitor C ₃ is an oscillation unit which generates a clock for timer count of the timer IC 10, the oscillation frequency is set by the time constant of CR. Output terminal P _O of the timer IC10 is connected to the base of the transistor Q ₅ through a current limiting resistor R _8. Furthermore, between the output terminal P _O timer IC10 and the ground Zener diode DZ is connected.

Switch SW _A to SW _C is composed of one of the slide switch as shown in FIG. 4, it is made as switches in conjunction. The switch SW _C has two contact pieces S _C and S _E
The has, in the state of FIG. 1 is connected to the base of the transistor Q ₄ to ground, the opposite state is adapted to connect the output terminal P _O timer IC10 to the ground.

Now, when the rectified current begins to flow through resistor R ₅ to the base of the transistor Q ₁ as described above, the transistor Q ₁ is started to turn on and begin the collector current I _C flows. The current I _C, the rectified current flows into the primary coil L _1, induces a voltage. Positive feedback to increase the current to the feedback coil L ₃ by the induced voltage of the primary coil L ₁ is a voltage in the same polarity induced flows to the base of the transistor Q _1, the transistor Q ₁ is turned on (FIG. 3 , t _ON period of the waveform I _C).
The current I _C during this period is I _C = (V / L ₁ ) · t (1) where V is the voltage applied to the primary coil L ₁ and L ₁ is the inductance of the primary coil L ₁ . So increase over time.

The collector current I _C by the resistor _{R 7 V R7 (= r 7} × I C)
(FIG. 3, waveform V _R7 ). When this voltage is reached the ON voltage V _BEQ2 transistor Q ₂ to increase, the transistor Q ₂ is turned on to bypass the base current of the transistor Q _1, begin to turn off the transistor Q _1. Therefore, in order to the primary coil L ₁ of the induced voltage polarity reversing the feedback coil L ₃ polarity is inverted, and the transistor Q ₁ is at once turned off (FIG. 3, t waveform V _CEQ1
OFF period). At the same time, electromagnetic energy accumulated in the primary coil L ₁ is emitted as an output current I _O through the output coil L ₂ (FIG. 3, waveform I _O), supplied to the battery B through the rectifier diode D ₂ Is charged.

The resistor R ₆ is turned on the motor M in the absence residual capacity to the battery B, that in the case of turning on the SW _A to SW _C, the storage time of the electromagnetic energy to be sufficient electric power to the motor M is supplied It should be longer than the above-mentioned t _ON period. That is, the resistance R ₆ to lower the impedance by connecting a resistor R ₇ in parallel, more to accumulate electromagnetic energy delaying the time until the transistor Q ₂ is turned on, thereby to increase the output current I _O I have to.

As described above, the charging control circuit including the timer IC 10 controls the charging time. That is, if charging is continued even after full charge, especially in NiCd batteries, the internal pressure rises and liquid leakage occurs, leading to a shortened life.

The timer IC10 switch SW _A to SW _C is illustrated state, i.e. during charging of the battery B, because the inter collector-emitter fallen base of the transistor Q ₄ is the ground is opened, the oscillating unit performing oscillation To generate a counter clock, whereby the timer IC 10 performs a counting operation. When the count value reaches a predetermined value, the output terminal
High signal is output from the P _0. This high signal is directed to the base of the transistor Q ₃ turns on the transistor Q _3,
Charging of the battery B transistor Q ₁ for bypassing the base current of the transistor Q ₁ is being turned off is ended.
On the other hand, the switch SW _A to SW _C is shown opposite state, i.e., during driving of the motor M, the base of the transistor Q ₄ are resistors R _1,
The transistor Q ₄ for the high voltage is applied through the R ₃ the oscillation operation of the oscillating unit is turned on is stopped. For this reason,
A clock for counting is not generated, the output terminal P ₀ of the timer IC10 remains low. Thus, the transistor Q ₁ is sustained the switching operation, a drive current is supplied to the motor M. When the driving of the motor M is turned on during the charging in the state shown in the figure, the timer IC 10 holds the count value immediately before the turning on, and when the motor M is switched to the charging side again, the count operation starts from the held count value. Is controlled so that the charging time becomes constant in total.

Switch SW _A to SW _C are those composed of a single slide switch, it is identical to that of the prior art shown in Figure 4.

That is, as shown in FIG. 3A, the slide switch has four contacts P _{A to} P _D, and has one resilient slide arm for making good contact with the following contact pieces S _{A to} S _D. 20
And the contact pieces S _{A to} S _E disposed so as to face the respective contacts of the one slide arm portion 20. In addition, contact piece
S _D is connected to the ground of the circuit at the common terminal, the contact piece S _E is connected to the transistor Q ₄ for counting the operation control of the timer IC 10.

Then, as shown in FIG.
The motor M is turned on while being slid to the SW _ON position, and only the storage battery B is charged while being slid to the SW _OFF position.

Now, if the attempts to switch from the on state of the motor M to the charge side by sliding the slide arms 20, or during the ON operation of the motor M, contacts abnormalities instantaneously due temporarily contacts P _D armature When electrically and opened from S _D, armature current flowing through the motor M through a contact point P _a from the contact piece S _a
It goes around S _B and S _C. Since the current wrapping around to the contact piece S _C is consumed flow into the zener diode DZ, a timer
Never excessive current flows to the IC10 of the output terminal P _O. The current wrapping around to the contact piece S _B part in the series circuit of the resistor R ₆ and R ₇ are consumed.

FIG. 2 is a charging circuit showing a second embodiment of the present invention.

The second embodiment is different from the first embodiment in that a Zener diode DZ is used instead of a semiconductor element such as a transistor.
It is obtained by using the Q _5.

That is, the emitter of the transistor Q ₅ is a timer
The IC10 of the output terminal P _O, base the contact piece S _C (FIG. 4 (a) see) of the switch SW _C, in which the collector is connected to ground.

Switch SW _A to SW _C is illustrated state, i.e. during charging of the storage battery B, the base of the transistor Q ₅ is in the OFF state for the open. Therefore, (low to high) charge control signal outputted from the output terminal P _O timer IC after a predetermined time has elapsed is led via a resistor R ₈ to the base of the transistor Q _3, the charging control function is fulfilled.

Now, the switch SW _A to SW _C is shown opposite state, i.e., during the ON operation, or if the motor M and the attempts to switch from the on state of the motor M to the charge side by sliding the slide arms 20, the contact abnormality instantaneous due temporarily contact P _D is electrically and opened from the contact piece S _D, armature current flowing through the motor M through a contact point P _a from the contact piece S _a S _B, S _C Try to go around. However, the contact piece S _C and the base of the relationship between the output terminal P _O timer IC10 transistor Q ₅ - due to the reverse (bias) directions by the emitter, the motor from the contact piece S _C to the output terminal P _O timer IC10 No excessive current flows from M. The current wrapping around to the contact piece S _B resistance
Some even series circuit of the R ₆ and R ₇ are consumed.

Incidentally, when the switch SW _B is not provided, the current flowing through the motor M flows in the other portions, or is consumed by the motor M itself. It is also possible to use a diode instead of the transistor Q ₅ in this embodiment. Switch In this case, the anode to the output terminal P _O timer IC 10, the cathode
It is sufficient to connect to the contact piece S _C of SW _C.

〔The invention's effect〕

As described above, according to the present invention, of the slide switch including one arm and three contacts, the contact for constantly connecting the arm to the ground is electrically connected to the contact of the arm. Even if it is opened, the constant voltage element prevents excessive current from flowing into the timer IC, so that the timer IC can be protected and a highly reliable charging circuit can be provided.

Further, even when the contact piece for constantly connecting the arm portion to the ground is electrically opened from the contact point of the arm portion as described above, the semiconductor element prevents the current itself from flowing into the timer IC. IC can be protected.

[Brief description of the drawings]

FIG. 1 is a circuit diagram of a charging circuit showing a first embodiment of the present invention, FIG. 2 is a circuit diagram of a charging circuit showing a second embodiment of the present invention, FIG. FIG. 4 shows switches SW _{A to} S
Shows the structure of a slide switch having a W _C, FIG. 5 is a circuit diagram of a conventional charging circuit. 10 Timer IC, 20 Slide arm, P _O Timer IC
Output end of AC, AC power supply, Pef rectifier circuit, T
Trans, B ...... battery, M ...... motor, R ₁ ~R ₈ ...... resistors, C ₁ ~C ₃ ...... capacitors, D _1, DZ ...... zener diode, D ₂ ...... diodes, Q ₁ to Q ₅ ...... Transistor, SW
_{A to} SW _C ... switch, S _{A to} S _E ... contact piece, P _{A to} P _D ... contact.

Claims (2)

(57) [Claims] 1. A charging circuit for charging a storage battery by charging control and supplying power from the storage battery to a load, comprising: one arm having at least three contacts; Independent three pieces that can be slid into the first piece for turning on and off the load and the second piece that is connected to the output terminal of the timer IC for charge control when the load is turned on And a charging circuit having an interlocking slide switch composed of a third contact piece for constantly connecting the arm to the ground, wherein a constant voltage element is connected between the output terminal of the timer IC and the ground. Characteristic charging circuit. 2. A charging circuit for charging a storage battery by charging control and supplying power from the storage battery to a load.
One arm having one contact and three independent contacts slidable relative to each contact of the one arm comprise a first contact for turning the load on and off, An interlocking slide switch including a second contact piece for connecting the output terminal of the timer IC for charge control to ground when the switch is on, and a third contact piece for constantly connecting the arm portion to ground; And a semiconductor element extending forward from the output terminal of the timer IC toward the second contact piece.