JPH07227046A - Electronic equipment - Google Patents

Abstract

PURPOSE:To shorten the charging time of a nickel-cadmium storage battery while preventing the 'memory effect' of the battery. CONSTITUTION:Notless than one more secondary batteries required for actually driving a load, a discharger, a switch group which switches the connecting destination of each battery, and a charging and discharging control section which switches the switches in accordance with the state are added to the conventional portable electronic equipment incorporating secondary batteries. When a secondary battery 117 is used in accordance with an instruction from a charging and discharging control section 114 in Fig. 1, a standby secondary battery 118 is charged after it is completely discharged and, when the charging of the battery 118 is completed, the battery 117 is switched to the battery 118. Since the above-mentioned operation is repeated, electronic equipment can be used during the charging time of a battery by giving chances to all batteries so that they can be discharged completely.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a battery charge / discharge control circuit for an electronic device which operates with a secondary battery such as a nickel-cadmium battery.

[0002]

2. Description of the Related Art With the miniaturization of various electronic devices, portable electronic devices incorporating a rechargeable secondary battery have been widely used.

However, in the nickel-cadmium battery widely used in these devices, if the operation of performing additional charging while the battery is discharging only a small amount is repeated,
There is a so-called "memory effect" in which the capacity of the battery is reduced, and this "memory effect" causes a reduction in the continuous use time of the portable device. For example, in the initial purchase of the device, it could be used for 4 hours with one charge, but after several additional charges, it could be used for only 3 hours with one charge.

As a conventional technique for automatically preventing and recovering the above-mentioned "memory effect", there is Japanese Patent Laid-Open No. Sho 62-62.
There are 25835 battery chargers. In this known example,
At the time of charging, all batteries were first connected to a discharger, and after complete discharge, the system automatically switched to charging.

[0005]

The known examples mentioned above are as follows:
Although it was effective as a means for eliminating the "memory effect" and prolonging the usage time of the battery, there is a problem that the charging time is longer because the mechanism is such that discharge is always performed prior to charging.

An object of the present invention is to prevent the "memory effect" and reduce the discharge time in the charging time.

[0007]

In order to solve the above-mentioned problems, the present invention detects the completion of charging of a secondary battery in a conventional electronic device when it reaches a predetermined voltage. Was added.

[0008]

[Operation] The charge completion detection unit operates the charge / discharge control unit so as not to perform the discharge before the charge is started until the charge completion is detected, so that the frequency of the discharge is reduced before the charge is started. I shortened the time.

Furthermore, a switch for selecting whether to connect or disconnect the secondary battery to the load is added, and the battery is disconnected from the load from the start of discharging to the end of charging, and the battery is detected by detecting the completion of charging. By operating the charge / discharge control unit so as to connect to the load, the load was not connected in the charge after the discharge once, and the charge was reliably performed until the full charge, thereby shortening the charging time.

Still another set of spare secondary batteries, a switch section for selecting whether the spare secondary batteries are connected to or disconnected from a load, and either one of the secondary batteries or the spare secondary batteries is a charger. And a switch to connect to the discharger is added, and the secondary battery connected to the charging part is charged and the secondary battery connected to the load and the discharging part are connected to the charging part. By operating the charging / discharging control unit so as to switch between the secondary batteries, the load can be driven using the other secondary battery even when one of the secondary batteries is being charged. The charging time can be eliminated.

A functional block diagram showing a configuration example of an electronic device according to the prior art is shown in FIG. 3, and a functional block diagram showing a configuration example of the electronic device according to claim 1 is shown in FIG.
FIG. 5 is a functional block diagram showing a configuration example of an electronic device according to claim 2, and FIG. 6 is a functional block diagram showing a configuration example of an electronic device according to claim 3.

[0012]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of the present invention will be described with reference to FIGS.

FIG. 1 is a functional block diagram showing an embodiment of the present invention. The apparatus used in this embodiment is divided into 101 electronic equipment main body and 102 detachable power source section.
When the power supply unit is separated from the main body, the operation is performed by the battery built in the main body of the electronic device 101. When the 102 power supply is connected, the power supply from the power supply drives the load and charges the battery.

FIG. 2 is a time chart showing the operating state of the present invention, in which the horizontal axis represents time, the vertical axis represents the presence or absence of connection of the 102 power supply unit, the presence or absence of operation of the 111 load, the 112 secondary battery and 118.
Charging power of spare secondary battery, 119 switch (A) 120
The selection state of the switch (B) 121 and the switch (C) is shown.

The operation will be sequentially described below with reference to FIGS.

In FIG. 2, the current time is 1. Until now, the 117 secondary battery was being charged, but the charging completion detection unit 116 detected the completion of charging, and learned that 114
The charge / discharge completion detector turns on the 119 switch (A),
Turn off 120 switches (B), 121 switches (C)
To the 1 side. As a result, the 111 load is driven by the 117 secondary battery. Further, the 114 charge / discharge control unit charges the next battery in 118 reserves, so that the 113 discharger is first operated to start discharging the remaining charging power.

Between times 1 and 4, the charging power of the 117 secondary battery intermittently decreases by the amount of the load operating, and the 118 spare secondary battery is charged by the 113 discharger. The charging power is monotonically reduced until it disappears.

Next, at time 5, when the 102 power supply is connected, the 111 load starts operating by the power from the power supply, and at the same time, the 117 secondary battery is additionally charged. Further, the 115 discharge detection unit detects the completion of discharge of the 118 secondary battery, and the 114 charge / discharge control unit, which knows this, stops the operation of the 113 discharger, and instead starts the operation of the 112 charger.

As seen from time 5 to 11, the 117 secondary battery consumes charging power by the load when the 102 power supply is not connected, and additionally charges the battery when the 102 power supply is connected. The charging power is repeatedly increased and decreased in order to perform.

On the other hand, in the spare 118, the secondary battery is charged when the 102 power supply unit is connected, and the charging power is monotonically increased.

At time twelve, the 116 charging completion detecting section detects that the 118 backup secondary battery has been charged, and the 114 charging / discharging control section which knows this has stopped the operation of the 112 charger and the 117 To switch the roles of the secondary battery and 118 spare secondary battery, turn off the switch 119 (A)
The switch (B) is turned on and the 121 switch (C) is switched to the 2 side.

Similarly, the 117 secondary battery and the 118 spare secondary battery continue to operate while repeatedly driving the load and charging.

In the present description, for simplification of the description, 2
I explained that when using one pair of batteries and one is in the selected state, the other is in the non-selected state, but since half the batteries are always idle, it is not a very efficient method. .

Actually, the use efficiency of the batteries can be improved by using three or more batteries and leaving only one of them in the non-selected state. In this case as well, the present invention can be applied by associating the number of switch groups and the charge / discharge control units with the number thereof.

For example, in the case where the present invention is implemented by adding one battery to an electronic device that originally uses four batteries, any four of the five batteries are selected and the remaining one is unselected. As a result, every time the battery in the non-selected state finishes charging after being completely discharged, the selection and the non-selection may be sequentially switched. In this case, there is an opportunity to perform a complete discharge once in five times, and the increase in the number of batteries due to the practice of the present invention
It will be relatively small, one for every four.

[0026]

As described above, according to the present invention,
The effect of reducing the charging time while preventing and recovering the "memory effect" of the nickel-cadmium battery or the like can be obtained.

[Brief description of drawings]

FIG. 1 is a functional block diagram showing an embodiment of the present invention.

FIG. 2 is a time chart showing an operating state of the electronic device of FIG.

FIG. 3 is a functional block diagram showing a configuration example of an electronic device according to a conventional technique.

FIG. 4 is a functional block diagram showing a configuration example of an electronic device.

FIG. 5 is a functional block diagram showing a configuration example of an electronic device.

FIG. 6 is a functional block diagram showing a configuration example of an electronic device.

[Explanation of symbols]

 Reference numeral 101 ... Electronic device main body, 102 ... Power supply section, 111 ... Load, 112 ... Charging section, 113 ... Discharger, 114 ... Charge / discharge control section, 115 ... Discharge completion detecting section, 116 ... Charge completion detecting section, 117 ... Secondary Battery, 118 ... Spare secondary battery, 119 ... Switch (A), 120 ... Switch (B), 121 ... Switch (C).

Claims (3)

[Claims] 1. A load operated by a secondary battery, a charging unit that charges the secondary battery, a discharging unit that discharges charging power of the secondary battery, and a voltage of the secondary battery that is discharging is a predetermined voltage. Discharge completion detection unit that detects that the secondary battery has dropped to the top, and when starting charging, first discharge the secondary battery by the discharging unit, and after knowing that the secondary battery has been discharged, stop discharging the secondary battery and start charging. In a device including a discharging unit and a charging / discharging control unit that controls the charging unit, the charging completion detection unit that detects that the voltage during charging has reached a predetermined voltage, and the charging / discharging control unit, Until the charging completion detection unit detects the completion of charging, a function that does not perform discharge by the discharger when starting charging is provided so that charging can be continued even if the charging operation is interrupted and restarted midway. , And once charging is complete, An electronic device characterized in that discharge is performed by a discharger before charging to reduce the frequency of discharge by the discharger and shorten the time required for charging. 2. The structure according to claim 1, wherein a switch for selecting whether to connect or disconnect the secondary battery to a load and a charge / discharge control section from the start of discharging to the end of charging,
A function to control the switch to disconnect the battery from the load and connect the battery to the load by detecting the completion of charging is provided, and from the start of discharging to the end of charging, the load is not connected and full charge is ensured. An electronic device that is characterized by being charged. 3. The structure according to claim 2, further comprising a pair of spare secondary batteries, a switch for selecting whether to connect or disconnect the secondary battery to a load, and the secondary battery or the spare secondary battery described above. A switch unit that connects one of the batteries to the discharge unit and the charging unit is provided, and the charging / discharging control unit receives the completion of charging of the secondary battery connected to the charging unit. A function to control the switch unit to switch between the connected secondary battery and the secondary battery connected to the charging unit discharge unit is provided, and when one secondary battery is charging without connecting the load, An electronic device characterized in that the load can be driven by using the other battery.