JPS6352643A - Charge controller - Google Patents

Abstract

(57) [Abstract] This bulletin contains application data before electronic filing, so abstract data is not recorded.

Description

DETAILED DESCRIPTION OF THE INVENTION Field of the Invention The present invention relates to a charging control device for a secondary battery used in a rechargeable vacuum cleaner or the like used in a general household.

BACKGROUND ART Generally, this type of charging control device has a configuration as shown in FIG. That is, in Fig. 6, voltage terminal 1
. Anode terminal is connected.

The cathode terminal of this diode 4 is connected to the anode of a secondary battery 5 to be charged, and the negative electrode of this secondary battery 5 is connected to the voltage terminal 2. This voltage terminal 2 is grounded. A resistor 6 for gate sensitivity adjustment is connected between the gate and cathode terminals of the main thyristor 3, and a resistor 7 is connected between the anode and cathode terminals. A smoothing circuit consisting of a diode 8 and a capacitor 9 is connected in parallel to the series circuit consisting of the main thyristor 3, a diode 4 and a secondary battery 5, and the cathode terminal of the diode 8 is connected to the main thyristor 3 through a resistor 1o.
The capacitor 9 is connected to the gate terminal of the resistor 11.
A series circuit consisting of a light emitting diode 12 and a light emitting diode 13 is connected in parallel. The anode terminal of the diode 14 is connected to the connection point a of the resistor 11 and the resistor 12, and the diode 14
The cathode terminal of is connected to the gate terminal of the main thyristor 3 and the anode terminal of the thyristor 16. The cathode terminal of this thyristor 16 is connected to the voltage terminal 2. A series circuit consisting of a Zener diode 1e and a resistor 1 is connected in parallel to the series circuit consisting of the diode 4 and the secondary battery 5.

The connection point between the anode terminal of the Zener diode 16 and the resistor 17 is connected to the gate terminal of the thyristor 15 via a resistor.

The operation of the above configuration will be explained below. First, if the charging potential of the secondary battery 6 does not reach the required potential (charging completion potential), the secondary battery 5 is connected between the diode 4 and the voltage terminal 2, and the voltage When a full-wave rectified AC voltage is applied to the terminals 1 and 2, a gate current flows through the resistor γ to the gate terminal of the main thyristor 3, and the main thyristor 3 is turned on.

At this time, the gate potential of the main thyristor 3 is held higher than the cathode potential. With the main thyristor 3 in the on state, a charging current flows to the secondary battery 6 via the main thyristor 3 and the diode 4, and the secondary battery 5 is charged. At this time, the light emitting diode 13 has a resistor 11.1.
A current flows through the light emitting diode 13, and the light emitting diode 13 emits light. Further, the diode 14 is in a reverse bias state and is in an off state, and furthermore, no gate current (gate trigger signal) flows through the thyristor 15, so the thyristor 15 is in an off state.

As charging continues, the voltage VB between the terminals of the secondary battery 6 becomes higher than the voltage level obtained by adding the forward drop voltage VD of the diode 4 to the Zener voltage vz of the Zener diode 1e, and the Zener current flows through the Zener diode 16. flows. As the Zener current flows, a voltage is generated in the resistor 17, and when the voltage across this resistor 1A, that is, the potential vR at the connection point becomes larger than the gate trigger voltage ■T of the thyristor 15, a voltage is generated at the gate terminal of the thyristor 15. A gate current is applied and the thyristor 16 is turned on. Since the thyristor 16 is turned on, the gate potential of the main thyristor 3 becomes lower than the cathode potential, and the main thyristor 3 is turned off. , the diode 14 also becomes conductive, and sufficient current does not flow through the light emitting diode 13 to emit light, so the light emitting diode 13 stops emitting light. Since the main thyristor 3 is turned off, charging by the main thyristor 3 is no longer performed, but a charging circuit consisting of the resistor 7, the diode 4, and the secondary battery 6 is formed, and a minute current flows to perform supplementary charging. .

Problems to be Solved by the Invention However, in general, if a secondary battery is left connected to a load for a long time, the secondary battery will discharge and its internal resistance will increase. For example, if left unattended for about three months, the internal resistance will reach several hundred nines.

When an attempt is made to charge such a so-called over-discharged battery using the conventional charging control device, when a charging current flows, the Zener voltage vZ is increased due to the internal resistance even though the secondary battery is not sufficiently charged. Voltage between terminals exceeding VB
As shown in FIGS. 4A and 4C, there was a problem in that charging was stopped immediately after charging started, and charging was not performed.

In addition, if overdischarge of the secondary battery occurs, the battery must be replaced, which is a big problem from an economic standpoint.

The present invention solves these conventional problems, and aims to realize a charging control device that can charge even over-discharged batteries.

Means for Solving the Problems To achieve this object, the charging control device of the present invention includes a charging current control element that controls the charging current to the secondary battery, and a drive that controls the driving of the charging current control element. a control unit, the drive control unit includes a base voltage setting unit that sets a reference voltage, a comparison unit that compares the base voltage with a terminal voltage of the secondary battery, and a voltage setting unit that sets a voltage at the charging terminal. a delay circuit section that turns on after a predetermined time delay after the signal is applied and maintains the on state for a predetermined time; and a determination that selectively outputs the drive signal based on the output signals from the comparison section and the delay circuit section. a timer section that maintains an on state for a certain period of time after the drive signal from the determination section is applied; and a timer section that transmits the output signal from the comparison section based on the drive signal from the determination section or the timer section. It has a switch part.

With the above configuration, when charging an over-discharged secondary battery, the internal resistance of the secondary battery will cause the terminals of the secondary battery to close during the slow discharge operation time. The voltage between the two terminals becomes larger than the reference voltage set by the reference voltage setting section. Therefore, the timer section is activated by a drive signal from the determination section. This timer section turns the switch section on after a certain time delay, but the switch section is kept off until then, and charging of the secondary battery continues. By this charging, the internal resistance of the secondary battery is restored to the normal internal resistance state of a secondary battery that has not been over-discharged, and even an over-discharged secondary battery can be charged.

EXAMPLE Below, a pulsating current signal obtained by rectifying the voltage shown in FIGS. 1 to 4 is applied for an example of the present invention. The charging terminal 19a is connected to the emitter terminal of a control transistor (charging current control element) 20 that controls charging current. A collector terminal of the control transistor 2o is connected to the positive electrode of the secondary battery 21 and the terminal a of the drive control section 22. The negative electrode of the secondary battery 21 is connected to the charging terminal 19b. A resistor 23°24 is connected to the emitter terminal of the control transistor 20.
The other end of the resistor 23 is connected to the anode side of the thyristor 25, the terminal of the drive control section 22, and the base terminal of the drive transistor 26. resistance 24
The other end is connected to the base terminal of the control transistor 2o and one end of the resistor 27, and the other end of the resistor 27 is connected to the collector terminal of the drive transistor 26. The emitter terminal of the drive transistor 26 is connected to the anode side of the light emitting diode 28, and the cathode side of the light emitting diode 28 is connected to the cathode side of the thyristor 26 and the drive control section 22.
It is connected to the charging terminal 19b together with the terminal d. Further, the gate terminal of the thyristor 26 is connected to the terminal C of the drive control section 22. The drive control unit 22 compares the inter-terminal voltage VB of the secondary battery 21 with the reference voltage - with a reference voltage setting unit 29 that sets a reference voltage - which is equal to the charging completion voltage of the secondary battery 21. Comparison section 3
0, a delay circuit section 31 that turns on after a time ta delay after the voltage signal is applied to the charging terminals 19a and 19b and maintains this on state for a time tbO, and a delay circuit section 31 that changes the clock count to a time t.
. a timer section 32 for selectively outputting a drive signal based on the input signals from the comparison section 30 and the delay circuit section 31; It has a switch section 34 and an OR circuit 36. Terminals a to d of the drive control section 22 are
First, the terminal a is connected to the non-inverting input terminal of the comparison section 30, the terminal is connected to the input side of the delay circuit section 31, the terminal C is connected to the output side of the switch section 32, and the terminal d is connected to the low potential side of the reference voltage setting section 29. There is. The high potential side of the reference voltage setting section 29 is connected to the inverting input terminal of the comparison section 300. The output side of the comparison section 30 is connected to the input side of the determination section 33 and the input side of the switch section 34. The output side of the determination section 33 is connected to the input side of the timer section 32 and one input side of the OR circuit 36. The output side of this timer section 32 is an OR circuit 3
The output side of the OR circuit 35 is connected to the luminance control terminal of the switch section 34.

The operation of the above configuration will be explained below.

First, the case of charging a secondary battery that has not been over-discharged will be described. Between connection points e and f (Fig. 1)
is connected, and a voltage obtained by rectifying the AC voltage is applied to the charging terminals 1ga and 19b. At this point, the charging control device is turned on (FIG. 3a). A voltage signal is applied to the base terminal of the drive transistor 2e and the b terminal of the drive control section 22 through the resistor 23. At this time, the thyristor 25 is in an off state with no gate trigger signal applied to its gate terminal. The base voltage is applied to the drive transistor 2e to turn it on, and current flows through the series circuit consisting of the resistors 24, 2, the drive transistor 26, and the light-emitting diode 28, causing the light-emitting diode 28 to emit light and the control transistor 20 to turn on. It becomes on state (FIG. 3f). With the control transistor 20 in a stable state, the secondary battery 21
Charging will begin. On the other hand, after time 1a has elapsed since the voltage signal was applied to the terminal of the drive control section 22, that is, the input side of the delay circuit section 31, the output signal of H level from the delay circuit section 31 remains on the input side of the determination section 33 for a time tb. (Figure 3b). Now, the voltage between the terminals of the secondary battery 21 VB
is applied to the terminal of the drive control section 22 and the non-inverting input side of the comparison section 3o, and when the voltage VB between the terminals becomes larger than the reference voltage - of the reference voltage setting section 29, the voltage of the comparison section 30 is applied. The H level output signal is applied to the input side of the determination section 33 and the input side of the switch section 34 (FIG. 3C). After the H level output signal of the delay circuit unit 31 is applied, the determination unit 33 applies the H level output signal of the comparing unit 3o, so that the determination unit 33 applies the H level output signal of the comparison unit 3o to the switch unit 34 via the OR circuit 35.
Apply a drive signal (FIG. 3d). The switch section 34 is turned on (FIG. 3e) by the drive signal from the determination section 33, and the output signal of the comparison section 30 is applied to the gate terminal of the thyristor 25 via the terminal C. The thyristor 25 is turned on when a gate trigger signal is applied to its gate terminal. Since the thyristor 26 is in the on state, the base potential of the drive transistor 26 is lower than the emitter potential, the drive transistor 26 is in the off state, and accordingly, the control transistor 20 is also in the off state (the third
Figure f), charging is finished.

Next, the case of charging an over-discharged secondary battery will be described. Note that after the charging control device is turned on (FIG. 4a), the H level output signal of the delay circuit section 31 is applied to the input side of the determination section 33 for a time tb (FIG. 4b), and the control transistor The operation until the battery 20 turns on and charging starts to the secondary battery 21 (FIG. 4 f) is the same as the case of charging the secondary battery 21 that has not been over-discharged, and the explanation thereof will be omitted. do.

Now, since the secondary battery 21 is over-discharged, its internal resistance is much larger than that of a battery that is not over-discharged, and the voltage VB between the terminals of the secondary battery 21 is set to the reference voltage immediately after the start of charging. An H level output signal (FIG. 4C) from the output side of the comparison section 30 is applied to the input sides of the determination section 33 and the switch section 34, which is much higher than the reference voltage (-) of the section 29. The H level output signal of the delay circuit section 31 is transmitted to the determination section 3.
Since the H level output signal of the comparison section 30 is applied to the determination section 33 during the time tb applied to the timer section 3, a drive signal is applied from the determination section 33 to the timer section 32. The timer unit 32 maintains the on state for a time tC.
Figure d), and then turns off, and the switch part 3
Apply a drive signal to 4. Note that by charging the secondary battery 21 while the timer section 32 is in the on state, the internal resistance due to overdischarge increases to the resistance value of the internal resistance of the secondary battery that is not overdischarged. Recovery, secondary battery 21
The inter-terminal voltage VB is the reference voltage V of the reference voltage setting section 29.
- If the value is smaller, the output signal of the comparator 30 becomes an L level signal (FIG. 4C). Now, since the switch section 34 is turned on (FIG. 4e), the output signal of the comparison section 30 is applied to the gate terminal of the thyristor 25 via the terminal C.

However, at this time, the output signal of the comparator 3o is an L level signal, the thyristor 25 remains off, and the secondary battery 2
Charging to 1 continues. After this, the inter-terminal voltage VB of the secondary battery 21 becomes more sharp υ than the reference voltage ■−, and the comparison unit 3
The output signal of 0 becomes an H level signal, a gate trigger signal is applied to the gate terminal of the thyristor 25, the thyristor 26 is turned on, the drive transistor 26 and the control transistor 20 are turned off (FIG. 4f), and charging is stopped. finish.

With the above configuration, the determination unit 33 has the H of the delay circuit unit 31.
While the level output signal is applied, the comparator 30
When the level output signal is applied to the determination unit 33, charging continues at least while the timer unit 32 is in the on state, and during that time the internal resistance of the over-discharged secondary battery is The battery will recover to its internal resistance value and become ready for charging.

In this embodiment, the control transistor 2o is used as the charging current control element, but a control element such as a thyristor may also be used. Further, although the light emitting diode 28 is used to indicate whether or not charging is being performed, other light emitting elements, a buzzer, etc. may be used.

Effects of the Invention As is clear from the description of the embodiments described above, according to the charging control device of the present invention, while the drive signal from the delay circuit section is applied to the determination section, the determination section receives the drive signal from the comparison section. When a drive signal is applied, the timer section is turned on,
As charging continues at least while the timer section is on, the internal resistance of the secondary battery, which had become extremely high due to overdischarge, is reduced to the internal resistance of a normal secondary battery that has not been overdischarged. The resistance value is restored and charging becomes possible. Therefore, according to the charging control device of the present invention, it is possible to realize a new function of being able to charge even over-discharged secondary batteries, and it is also possible to eliminate the need to replace over-discharged secondary batteries. It has economic effects.

[Brief explanation of the drawing]

Fig. 1 is a circuit diagram of a charging control device according to an embodiment of the present invention, Fig. 2 is a circuit diagram of a main part of the charging control device, and Fig. 3 is a charging of a secondary battery that is not over-discharged in the same embodiment. Fig. 4 is a diagram of main signal waveforms when an over-discharged secondary battery is charged in the same embodiment. Fig. 5 is a circuit diagram of a conventional charging control device. Fig. 6 FIG. 2 is an explanatory diagram when charging is performed using a conventional charging control device. 19a, 19b...Charging terminal, 20...
...Control transistor (charging current control element), 22...
... Drive control section, 29 ... Reference voltage setting section, 3o ... Comparison section, 31 ... Delay circuit section, 32 ... Timer section , 33... determination section, 34... switch section.

Claims (1)

[Claims] A charging terminal, a charging current control element that controls charging current to a secondary battery, and a drive control section that controls drive of the charging current control element, and the drive control section controls a reference voltage that sets a reference voltage. a setting section, a comparison section that compares the reference voltage and the voltage between the terminals of the secondary battery, and a setting section that is turned on after a certain period of time after the voltage signal is applied to the charging terminal, and this on state is maintained for a certain period of time. a delay circuit section that selectively outputs a drive signal based on the output signals from the comparison section and the delay circuit section, and a determination section that maintains an on state for a certain period of time after the drive signal from the determination section is applied. A charging control device comprising: a timer section; and a switch section that transmits an output signal from the comparison section based on a drive signal from the determination section or the timer section.