JP2962538B2 - Battery charging circuit in electronic equipment - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a battery charging circuit in an electronic device, and more particularly to a battery charging circuit in a cordless telephone, a portable telephone and the like using a battery requiring charging.

[0002]

2. Description of the Related Art Generally, a battery charging circuit in a conventional electronic device has a configuration as shown in a block diagram of FIG. That is, a voltage stabilizing circuit 3 connected to an input power supply 2 obtained by rectifying an AC power supply, a main object circuit 4 to which a driving current is supplied from the voltage stabilizing circuit 3, and a battery charging circuit Current limiting circuit 6 which is part of 5
And a battery connection terminal 7 connected between the input power supply 2 and the current limiting circuit 6 is provided outside the electronic device, and a battery-using device 8 requiring charging is connected to the battery connection terminal 7. I was

[0003]

However, the above-mentioned conventional battery charging circuit has an additional function with respect to the main purpose circuit 4 of the electronic device 1, and therefore is configured in parallel with the main purpose circuit 4. In this case, the current consumed by the electronic device 1 including the charging circuit 5 is only the driving current (for example, 100 mA) from the voltage stabilizing circuit 3 during non-charging, whereas the voltage stabilizing circuit 3 during charging is used. In addition to the drive current (100 mA) from the power supply, the charge current of the charging circuit 5 (for example, 50 mA) is increased (total 150 mA), and accordingly, inside the electronic device 1, the voltage from the voltage stabilizing circuit 3 and the main target circuit 4 is increased. There is a problem that the heat generated by the current limiting circuit 6 is added in accordance with the heat generation, resulting in a large power loss. SUMMARY OF THE INVENTION It is an object of the present invention to provide a battery charging circuit in an electronic device that solves the above-mentioned conventional problems and suppresses current consumption during charging and suppresses heat generation in the device.

[0004]

A battery charging circuit in an electronic device according to the present invention includes a voltage stabilizing circuit for stabilizing an input power supply voltage, and a main object circuit to which a driving current is supplied from the voltage stabilizing circuit. In the electronic device provided with, a battery charging circuit is connected to the input power supply and the input side of the main purpose circuit, the main purpose circuit is connected to the drive current from the voltage stabilization circuit and the charging current It is configured to be driven by the addition current.

[0005]

The main object circuit is driven by the sum of the driving current from the voltage stabilizing circuit and the charging current of the battery charging circuit. Therefore, at the time of charging, the drive current from the voltage stabilizing circuit is reduced by the amount of the charging current of the battery charging circuit from that at the time of non-charging, and as a result, the current consumption of the electronic device at the time of charging does not increase relative to the time of non-charging. This saves energy and suppresses heat generation inside the electronic device.

[0006]

FIG. 1 is a block diagram showing an embodiment of a battery charging circuit in an electronic apparatus according to the present invention. The same components as those in FIG. 2 are denoted by the same reference numerals. In FIG.
A battery charging circuit 5 including a current limiting circuit 6 and a battery connection terminal 7 is connected between the input power supply 2 and the input side of the main purpose circuit 4. In this configuration, the drive current required for the main purpose circuit 4 of the electronic device 1 is the same (100 mA) as in FIG. 2 for comparison with the conventional circuit of FIG. When charging is not being performed, a driving current (100 mA) is supplied to the main purpose circuit 4 only from the voltage stabilizing circuit 3. Next, when charging is performed by connecting the battery-using device 8 requiring charging to the battery connection terminal 7, the driving current from the voltage stabilizing circuit 3 is partially the charging current flowing through the battery charging circuit 5 (for example, 50 mA ), The driving current from the voltage stabilizing circuit 3 decreases (from 100 mA to 50 mA).
The driving current supplied to the main purpose circuit 4 is the sum of the driving current (50 mA) from the voltage stabilizing circuit 3 and the charging current (50 mA) of the battery charging circuit 5 (100 mA).
Becomes Accordingly, the current flowing through the electronic device 1 is constant regardless of whether the battery is charged or not, and the power consumption is also constant. Further, the voltage applied to both ends of the current limiting circuit 6 decreases, and the reactive power that becomes heat decreases. As a result, the heat generation inside the electronic device 1 can be reduced together with the heat generation of the voltage stabilizing circuit 3.

In particular, when the electronic device 1 is a base unit of a cordless telephone and the battery-powered device 8 requiring charging is a child unit, the child unit is placed on the base unit and charged, and is charged. Since the heat generated in the base unit is smaller than that in the conventional circuit, the amount of heat for heating the slave unit is small, and discomfort can be prevented. In the circuit shown in FIG. 1, depending on the selection of the charging current value of the battery charging circuit 5, if most of the driving current required for the main purpose circuit 4 can be supplied by the charging current of the battery charging circuit 5, The voltage stabilizing characteristic of the voltage stabilizing circuit 3 is improved, which is the most effective. Further, as another embodiment, the charging current of the battery charging circuit 5 is controlled by the main purpose circuit 4.
If the driving current is smaller than the required driving current, the battery charging circuit 5 is connected between the input power supply 2 and the input side of the main purpose circuit 4 so that the charging current of the battery charging circuit 5 If the number is larger, the battery charging circuit 5 may be connected to both ends of the input power supply 2.

[0008]

According to the battery charging circuit for an electronic device according to the present invention, the current consumed by the electronic device is constant regardless of whether the battery is charged or not, and energy is saved.
In addition, since the heat generation inside the electronic device is also suppressed, especially in the case of a cordless telephone, the amount of heat generated in the base unit in a charged state is reduced as compared with the conventional circuit, so that the amount of heat for heating the slave unit is small and discomfort can be prevented. .

[Brief description of the drawings]

FIG. 1 is a block diagram showing one embodiment of a battery charging circuit in an electronic device according to the present invention.

FIG. 2 is a block diagram of a battery charging circuit in a conventional electronic device.

[Explanation of symbols]

 REFERENCE SIGNS LIST 1 electronic device 2 input power supply 3 voltage stabilization circuit 4 main purpose circuit 5 battery charging circuit 6 current limiting circuit 7 battery connection terminal 8 battery-using device for practical use of charging

Claims (3)

(57) [Claims] A voltage stabilizing circuit (3) for stabilizing a voltage of an input power supply (2), and a main purpose circuit (4) supplied with a driving current from the voltage stabilizing circuit (3). In the electronic device (1), a battery charging circuit (5) is connected to the input power supply (2) and the input side of the main purpose circuit (4),
A battery in an electronic device, wherein the main object circuit (4) is driven by a sum of a driving current from the voltage stabilizing circuit (3) and a charging current of the battery charging circuit (5). Charging circuit. 2. The battery charging circuit according to claim 1, wherein the battery charging circuit includes a current limiting circuit and a battery connection terminal. 3. The battery charging circuit according to claim 2, wherein the electronic device is a base unit of the cordless telephone, and a slave unit of the cordless telephone is connected to the battery connection terminal.