JPH07322523A - Battery-charging control method in electronic apparatus - Google Patents

Abstract

PURPOSE:To obtain a battery-charging control method in which a battery which has been charged fully and mounted is prevented from being charged excessively by a method wherein the terminal voltage of the battery is detected when the battery is mounted or when a power supply is turned on, a charging operation is set to start in a boosting charging mode when the battery is at an empty charging level and the charging operation is set to start in an ordinary charging mode when the battery is not at the empty charging level. CONSTITUTION:When a secondary battery 2 is mounted or a power-supply switch is turned on at a slave telephone set 100 for a cordless telephone set, its terminal voltage is detected by a battery-voltage detection circuit 23. Then, a microcomputer 13 sets the counting value of a timer counter 17 at 0 when the terminal voltage of the secondary battery 2 is at an empty charging level. On the other hand, the microcomputer sets the counting value of the timer counter 17 at Vmax when the voltage is not at the empty charging level. Then, when the slave telephone set 100 is placed on a charging stand 4, it is charged by a boosting charging operation up to the counting value Vmax when the timer counting value set at the timer counter 17 is set at 0, and it is charged by an ordinary charging operation when the counting value is set at Vmax.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a battery charging control method suitable for controlling charging of a battery of an electronic device such as a cordless telephone, a pager or a portable personal computer which is a cordless communication device.

[0002]

2. Description of the Related Art As a conventional example, a cordless telephone will be described. The battery terminal voltage drops and the device needs to be charged to operate the equipment normally.The fast charging mode for quickly charging a charged battery at an empty charge level with a large current, and the battery terminal voltage above a specified value. Yes, it has a normal charge (trickle charge) mode that charges a battery to be charged at a full charge level that normally operates the equipment with a small current, and the setting of that mode is switched using a timer counter. .

That is, the battery to be charged is set in the quick charge mode.
The value of the timer counter in the state at the full charge level
Is set to the maximum value (Vmax). Then cordless power
The state of use of the handset, such as communication time, standby time, or
Is the charging time when placed on the base unit or charging stand, etc.
Increases or decreases the set value of the timer counter. Usually this
Depending on the setting value of the timer counter of
When placed on a table, the set value of the timer counter is the specified value
(V min) or less
The mode is switched. Also, full charge
Battery life is switched to normal charging mode near level
Never shrink.

[0004]

[Problems to be Solved by the Invention]
If you are using an electronic device like
Or when the power switch is input, etc.
The counter value is initialized to zero, so
Fixed value (V min) or less Becomes Therefore, the quick charge mode
Will be started from. Therefore, the same battery can be used many times
When reattached, it will be charged in the quick charge mode each time
This can lead to overcharge. The power switch
Even if the power switch is turned on / off many times,
And may overcharge as well.

Further, in the charging control method for the cordless communication device disclosed in Japanese Patent Laid-Open No. 5-56574, the memory of the timer counter is stored and stored in the storage means such as the EEPROM so that the memory of the timer counter is not lost when the power switch is turned off. In this case, even if the battery to be charged is newly replaced, the value of the timer counter is based on the charging information of the battery to be charged before replacement, and the value of this timer counter causes a new replacement. The charging mode for the charged battery is determined. Therefore, even when the battery is newly replaced and the current to be charged is at the empty charge level, the normal charge mode may be set in some cases, resulting in insufficient charging. On the other hand, even if the newly replaced battery to be charged is at the full charge level, depending on the value of the previous timer counter, it may be in the quick charge mode even if the timer counter is decremented a little, resulting in overcharging. There is a fear.

The present invention has been made to solve the above problems, and it is an object of the present invention to provide a battery charge control method for an electronic device capable of preventing overcharge of the battery when the battery is attached or when the power is input. To aim.

[0007]

A battery charging control method for an electronic device according to the present invention has at least a fast charging mode with a large current and a normal charging mode with a small current, and determines whether to switch the charging mode. In a battery charge control method in an electronic device using a timer counter as at least one of the elements, when a battery is attached or power is input,
When starting charging, it is detected whether the terminal voltage of the battery is at an empty charging level that requires charging, and when the detected terminal voltage is at an empty charging level, charging is started in the quick charging mode. And a setting step of setting to start charging in the normal charging mode when the detected terminal voltage is not at the empty charging level.

[0008]

A method for controlling battery charge in an electronic device according to the present invention detects whether the terminal voltage of the battery is at an empty charge level that requires charging when the battery is attached or when power is input. Set to start charging in the fast charge mode when the detected terminal voltage is at the empty charge level, and set to start charging in the normal charge mode when the detected terminal voltage is not at the empty charge level, When the electronic device is ready to be charged,
The battery is charged in the charging mode according to the setting step, fully charged, and is prevented from being rapidly charged, and acts to prevent overcharging of the battery.

[0009]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of the present invention will be described below with reference to the drawings. FIG. 1 is a block diagram showing a configuration of a cordless telephone handset 100 in which a battery charging control method for an electronic device according to this embodiment is used. In the figure, the child device 100 is placed on the parent device or the charging stand 4. 2 is a rechargeable secondary battery (battery); 3 is a power supply terminal 5 of the master unit or the charging stand 4 when the slave unit 100 is placed on the master unit or the charging stand 4.
It is a charging terminal that contacts with. The positive electrode side of the charging terminal 3 is configured to be connected to the secondary battery 2 via the diode 8 via the switch 8 through either the rapid charging circuit 9 or the normal (trickle) charging circuit 10. The secondary battery 2 is connected to the power supply circuit 11. In the child device 100, a communication circuit 12 for performing wireless communication with the parent device,
A microcomputer 13 for controlling the communication circuit 12, etc., a power switch 25, etc. are provided. The microcomputer 13 includes a switch signal output port 13a to the switch 8, an input port 13b from the detection circuit 14 that detects whether the slave 100 is on the charging stand 4, a communication circuit 12 control port 13c, a system control or a battery. Input port 13 of ROM 15 that stores the charge control program
d, control port 13e of RAM16, timer counter 1
7, a control port 13f, a battery voltage detection port 13g of the battery voltage detection circuit 23, and the like.

FIG. 2 is a flowchart showing a battery charging control process by the microcomputer 13 when the secondary battery 2 is attached or the power switch is turned on. In the battery charging control method for the cordless telephone of this embodiment, when the secondary battery 2 is attached, the terminal voltage of the attached secondary battery 2 is detected by the battery voltage detection circuit 2.
When it becomes possible to charge the battery, the microcomputer 13 determines whether to perform the rapid charge or the normal charge based on the detection result.

That is, in step S2 following step S1 of the initial setting, the battery voltage detection circuit 23 detects that the terminal voltage of the secondary battery 2 has dropped, and the battery which is required to be charged in order to operate the equipment normally is empty. Set the threshold value that indicates the charge level. If it is less than the set value, 'Lo
Output w'level. The microcomputer 13 determines whether the terminal voltage of the secondary battery 2 is the “Low” level indicating the empty charge level. When it is the "Low" level indicating the empty charge level, "0" is set to the counter value of the timer counter 17 (step S3). On the other hand, when it is not the “Low” level indicating the empty charge level, the counter value of the timer counter 17 is set to Vm.
It is set to ax (step S4).

In the following step S5, the slave unit 10 is placed on the charging stand 4.
It is determined whether or not 0 is placed, and if it is placed, if the timer counter value set in the timer counter 17 is "0", the value is rapidly increased until the timer counter value becomes Vmax in step S7. If the charging is Vmax, the normal charging is performed in step S8. The CPU 13 selects the quick charge or the normal charge by selecting the switching signal output port 13a.
This is done by controlling the switch 8 via.

Therefore, in this embodiment, when the secondary battery 2 is mounted and the cordless handset 100 is placed on the charging stand 4, whether or not rapid charging should be performed from the terminal voltage of the mounted secondary battery 2 is determined. As a result of the CPU's determination, even if the slave unit 100 is placed on the charging stand 4 with the fully charged secondary battery 2 reattached, rapid charging is not performed and overcharging does not occur. Further, overcharging does not occur even if the power switch 25 is repeatedly turned on / off.

[0014]

As described above, according to the present invention, at the time of the battery device or the power input, the charge state of the battery is always detected and the charge mode corresponding to the state is set, so that the full charge level is reached. It is possible to prevent the battery from being overcharged even if it is reattached, and to prevent it from being overcharged even if the power switch is repeatedly turned on and off.

[Brief description of drawings]

FIG. 1 is a block diagram showing a configuration of a slave unit of a cordless communication device using a battery charging control method in an electronic device according to an exemplary embodiment of the present invention.

FIG. 2 is a flowchart illustrating a battery charge control method in an electronic device according to an exemplary embodiment of the present invention.

[Explanation of symbols]

 2 Secondary Battery (Battery) 8 Switch 9 Rapid Charging Circuit 10 Normal Charging Circuit 11 Power Supply Circuit 12 Communication Circuit 13 Microcomputer 14 Detection Circuit 15 ROM 17 Timer Counter 23 Battery Voltage Detection Circuit 25 Power Switch 100 Handset

Claims (1)

[Claims] 1. A battery charging control in an electronic device which has at least a fast charging mode with a large current and a normal charging mode with a small current, and uses a timer counter as at least one of the judgment elements for switching the charging mode. In the method
When the battery is attached or the power is input, when starting charging, it is detected whether the terminal voltage of the battery is at an empty charge level that requires charging, and when the detected terminal voltage is at the empty charge level, the In an electronic device characterized by having a setting step for setting to start charging in the quick charging mode, and for setting to start charging in the normal charging mode when the detected terminal voltage is not at the empty charging level. Battery charge control method.