JPS6213397Y2 - - Google Patents

Description

[Detailed Description of the Invention] The present invention relates to a device for charging a battery to be charged using a rectified pulsating output of an AC power source.

This type of device detects a predetermined charging voltage of a battery that has been rapidly charged with a large current, and switches the charging current of the battery from a large current for rapid charging to a small current for supplementary charging. The average charging current characteristic in this case is shown in FIG. 1, and the current gradually decreases from large current ₁ to small current ₂ after detection time t ₁ of a predetermined charging voltage of the battery. However, as shown in the characteristics, the battery voltage has a peak point ₁ ,
Depending on the selection of the predetermined charging voltage of the battery, the supplementary charging current will gradually increase as shown by the dashed line characteristic ₃ based on the decrease in battery voltage after the peak point, causing the battery to overcharge. There is a risk of

The present invention has been devised in view of these points, and one embodiment of the present invention will be described below based on the drawings. FIG. 2 is an electrical circuit diagram of the device according to the invention. In this drawing, 1 is a charging power source, and the output of a step-down transformer T to which an AC power source E is applied is rectified by a full-wave rectifier circuit D ₁ , and its output terminals 2 and 3 have rectified pulsating outputs. is obtained. A series circuit of a silicon controlled rectifier (hereinafter referred to as SCR) S as a power supply element and a battery to be charged B is connected between the output terminals. The gate of SCR,S is connected to output terminal 2 via diode _D2 and resistor _R1 .

Next, 4 is a control circuit which detects a predetermined charging voltage of battery B and controls to cut off SCR and S, and is constructed as follows. That is, a resistive voltage divider circuit 5 connected in parallel to the battery B, a first transistor Q ₁ that is turned on by a predetermined divided voltage of the circuit, a second transistor Q ₂ that is cut off by the conduction of the first transistor, and a Third and fourth transistors Q ₃ and Q ₄ are made conductive due to an increase in their collector voltage due to the interruption of the second transistor; and a fifth transistor is made conductive due to the conduction of the fourth transistor and bypasses the gate signals of SCR and S. It consists of Q ₅ . The resistive voltage divider circuit 5 is constructed by connecting resistors R ₂ , R ₃ , R ₄ and a variable resistor R _v in series, and by connecting a positive temperature sensing element P in parallel to the resistor R ₃ . The contact 6 of the variable resistor R _v is connected to the base of the first transistor Q ₁ , the collector of which is connected to the output terminal 2 via the resistor R ₅ and to the second transistor Q 1 .
Connected to the base of _Q2 . The collector of the second transistor is connected to the output terminal 2 via a resistor R ₆ and to the output terminal 3 via a diode D ₃ and a resistor R ₇ . Both ends of the resistor _R7 are connected to the base and emitter of the third transistor _Q3 , and the base of one of the third and fourth transistors _Q3 and _Q4 is mutually connected to the collector of the other. The emitter and base of the fourth transistor _Q4 are resistors _R8 and _R9 , respectively.
is connected to the output terminal 2 via the transistor Q5, and its emitter is connected to the base of the fifth transistor _Q5 . Fifth
The emitter of the transistor is a resistor _R1 and a diode
The collector is connected to the connection point of D ₂ and the output terminal 3, and a series circuit of a light emitting diode L and a resistor R ₁₀ is connected between the emitter and collector.

7 is a signal circuit that detects the rising voltage at the output terminal 2 when the SCR, S is cut off and activates the control circuit 4, and is connected in series with a constant voltage diode Z and a resistor R ₁₁ that conducts at the rising voltage at the output terminal 2. It consists of a circuit and is provided between the output terminal 2 and the base of the third transistor _Q3 .

In the above configuration, when battery B starts charging, a resistor _R1 and a diode are connected to the gates of SCR and S.
A gate signal is applied via _D2 , causing SCR,S to conduct and charge battery B. In this case, the second transistor Q ₂ is conductive, the other transistors Q ₁ , Q ₃ , Q ₄ , and Q ₅ are in a cut-off state, and the light emitting diode L is lit to indicate that charging is in progress. Further, in this case, the voltage at the output terminal 2 is low as shown by the voltage characteristics in FIG. 1, and no signal current flows through the signal circuit 7.

As the charging time progresses, battery B is charged and exhibits charging voltage characteristics. When battery B reaches a predetermined voltage V ₁ , the first transistor Q ₁ becomes conductive due to a proportional voltage corresponding to this predetermined voltage. Therefore, the collector voltage, that is, the base voltage of the second transistor _Q2 decreases, and the second transistor is cut off. Therefore, the collector voltage of the second transistor becomes large, and the voltage of the resistor R ₇ becomes large, so that the third transistor Q ₃ becomes conductive, and its collector voltage, that is, the base voltage of the fourth transistor Q ₄ becomes low, and the fourth transistor Q 3 becomes conductive. Since the transistor becomes conductive and its output becomes the base current of the third transistor Q ₃ , the third and fourth transistors Q ₃ and Q ₄ promote mutual conduction. Since the fifth transistor _Q5 becomes conductive due to the conduction of the fourth transistor _Q4 , the gate signal of SCR,S flows through the fifth transistor, and SCR,S is cut off. Furthermore, in this case, the fifth transistor _Q5 is turned on, causing the light emitting diode L to go out, thereby notifying the completion of charging of the battery B.

Thus, at the time _t1 when the predetermined voltage of battery B is detected, battery B
The high current charging ends, but the battery voltage drops below the predetermined voltage due to the interruption of SCR and S, and at time t ₁
After that, the battery is repeatedly charged and stopped, which is what is called joggle charging. In this case,
As shown in the characteristics, the voltage at the output terminal 2 when charging is stopped when SCR and S shut off becomes a no-load voltage and rises. The predetermined voltage V ₂ causes the constant voltage diode Z to conduct, and a signal current is applied to the base of the third transistor Q ₃ via the signal circuit 7, and the third and fourth transistors Q ₃ and Q ₄ to conduct. 5 Transistor Q ₅ is made conductive and SCR and S are cut off. Therefore, the cut-off period of SCR, S after the time _{t 2 when} the constant voltage diode Z becomes conductive due to the predetermined voltage V 2 becomes longer due to the presence of the signal current from the signal circuit 7.
As shown in characteristic ₄ , the average charging current decreases despite the decrease after the peak point of the charging voltage characteristic.

As described above, according to the present invention, due to the presence of the signal circuit, the supplementary charging current of the battery can be reduced despite the decrease after the peak point of the battery voltage characteristics, and overcharging of the battery can be prevented. is possible,
The predetermined charging voltage of the battery can be selected arbitrarily.

[Brief explanation of the drawing]

FIG. 1 is a charging characteristic diagram of a battery, and FIG. 2 is an electric circuit diagram showing an embodiment of the device according to the present invention. 2, 3...Output end, S...Silicon controlled rectifier, B...Battery to be charged, 4...Control circuit, 7...
signal circuit.

Claims (1)

[Scope of utility model registration request] A control circuit that provides a series circuit of a silicon-controlled rectifier and a battery to be charged at the output end of the rectified pulse output of an AC power supply, and detects a predetermined charging voltage corresponding to the peak of charging voltage characteristics of the battery and controls the silicon-controlled rectifier to shut off. a signal for detecting the voltage at the output terminal of the charging power source that increases as a no-load voltage when the silicon-controlled rectifier is cut off, and operating the control circuit regardless of the drop in the charging voltage after the rectifier is cut off. A battery charging device equipped with a circuit.