JPS63124731A - Charger of secondary battery in electronic equipment - Google Patents

Abstract

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

Description

DETAILED DESCRIPTION OF THE INVENTION [Object of the Invention] (Field of Industrial Application) The present invention relates to a charging device for a secondary battery in an electronic device.

(Prior Art) Conventionally, this type of charging device has been constructed as shown in FIG. 3, for example. In this device, when the input terminal 1 is connected to an external power source (not shown), a switch 2 is closed and a switch 3 linked to the switch 2 is opened. Here, when the switch 4 is closed, power is supplied from the external power source to the input terminal 1 → switch 2 → switch 4 → main circuit 5, and the main circuit 5 in the electronic device is supplied with power.
is activated. At this time, power is also supplied from the input terminal 1 to the charging current supply circuit 6, and the charging current supply circuit 6 supplies a preset constant level of current to the secondary battery 8 via the diode 7 for preventing reverse current.

Therefore, the secondary battery 8 is charged, and its terminal voltage changes and becomes higher. The charging control circuit 9 detects whether or not the terminal voltage of the secondary battery 8 has reached a preset voltage. A signal indicating that the supply is to be stopped is applied to the charging current supply circuit 6. When the charging current supply circuit 6 receives this signal, it stops supplying current to the secondary battery 8. Next, if the input terminal 1 is not connected to an external power source, the switch 2 is queried, and the switch 3 interlocked with this switch 2 is closed. In this state, power is supplied from the secondary battery 8 in the order of switch 3 → switch 4 → main switch.

However, since the secondary battery 8 is generally charged quickly,
Since the charging current supply circuit 6 and the battery 8 generate a large amount of heat, and the main circuit 5 also generates heat, there is a problem that the electronic device generates a large amount of heat. Moreover, portable electronic devices are usually required to be miniaturized;
For example, if the heat dissipation fins for dissipating the heat are made larger, or if the charging circuit and the main circuit are separated to disperse the heat source, there is a problem in that downsizing becomes difficult.

(Problems to be Solved by the Invention) In this way, in conventional devices, electronic! ? If the secondary battery is rapidly charged while the device is operating, the electronic
There was a problem in that the heat generated by the device was extremely large.

Therefore, the present invention provides a charging device for a secondary battery in an electronic device that prevents both the electronic device and the charging circuit from generating heat at the same time even if the secondary battery is charged while the electronic device is operating. The purpose is to provide

(Structure of the Invention) (Means for Solving the Problems) The present invention provides a determination means for determining whether or not an electronic device is operating, and a determination means for determining whether or not an electronic device is operating. In this case, the secondary battery is gradually charged by power supply from an external power supply, and when the electronic device is determined to be not operating by the determination means, the secondary battery is rapidly charged by power supply from an external power supply. It is characterized by being equipped with a charging means.

(Function) According to the present invention, the secondary battery is gradually charged when the device is in operation, and the secondary battery is rapidly charged when the electronic device is not in operation, so that both the electronic device and the charging circuit can be charged. There are no cases where the lights become hot at the same time.

(Example) Hereinafter, an example of the present invention will be described in detail with reference to the accompanying drawings.

FIG. 1 is a block diagram showing an embodiment of a charging device according to the present invention. In this embodiment, the apparatus shown in FIG. 3 is provided with a determination circuit 10 for determining whether or not the main circuit 5 is operating.

In this figure, parts that perform the same functions as those of the apparatus shown in FIG. 3 are given the same reference numerals for convenience of explanation.

In the device of this embodiment, when the input terminal 1 is connected to an external power source (not shown), the switch 2 is closed and the switch 3 linked to this switch is opened. here,
When the switch 4 is closed, power is supplied to the main circuit 5 in the electronic device, and the main circuit 5 is activated. At this time, the determination circuit 10 detects the potential on the input side of the main circuit 5, determines that the main circuit 5 is operating, and applies a signal indicating this determination result to the charging current supply circuit 6 and the charging control circuit 9. . When the charging current supply circuit 6 receives a signal indicating the determination result, it supplies a small current corresponding to the operation of the main circuit 5 to the secondary battery 8 via the diode 7. Therefore, the secondary battery 8 is gradually charged, and the charging current supply circuit 6 does not generate heat; however, the main circuit 5 generates heat because it is operating. - On the other hand, the charging control circuit 9 has a first terminal voltage when the secondary battery 8 is gradually charged and filled, and a second terminal voltage when the secondary battery 8 is rapidly charged and filled. are each indicated in advance. When the charging control circuit 9 receives a signal indicating the determination result from the determination circuit 10, the charging control circuit 9 gradually charges the battery 2 when the main circuit 5 is activated.
It is detected whether the terminal voltage of the secondary battery 8 has reached the first terminal voltage, and if it has reached the voltage, a signal indicating that the supply of power is to be stopped is applied to the charging current supply circuit 6. When the charging current supply circuit 6 receives this signal, it stops supplying current to the secondary battery 8. However, if the charging current in this state is set to a small value that does not particularly require the control uO, the detection of the terminal voltage of the battery may be omitted.

Also, when switch 4 is opened, power is not supplied to main circuit 5,
Main circuit 5 does not operate. At this time, the determination circuit 10 detects the potential on the input side of the main circuit 5, determines that the main circuit 5 is not operating, and applies a signal indicating this determination result to the charging current supply circuit 6 and the charging control circuit 9. . When the charging current supply circuit 6 receives a signal indicating the determination result, it supplies a large current corresponding to when the main circuit 5 is not operating to the secondary battery 8 via the diode 7. Therefore, the secondary battery 8 is rapidly charged, and the charging current supply circuit 6 generates a large amount of heat.

However, since the main circuit 5 is not operating at this time, no heat is generated from the main circuit 5. In addition, when the charging control circuit 9 receives a signal indicating the face recognition result from the determination circuit 10, the charging control circuit 9 rapidly charges the battery 2 when the main circuit 5 is not activated.
It is detected whether the terminal voltage of the next battery 8 has reached the second terminal voltage, and if it has reached the second terminal voltage, a signal indicating that the current supply is to be stopped is applied to the charging current supply circuit 6. When the charging current supply circuit 6 receives this signal, it stops supplying current to the secondary battery 8.

FIG. 2 is a circuit diagram showing the configuration of the charging current supply circuit 6, in which a resistor 21, Darlington connection transistors 22, 23, and a constant voltage diode 2 are connected between the input terminal 1 and the diode 7.
A constant current circuit for small current consisting of 4, a resistor 25, a Darlington connection transistor 26, 27, a constant voltage diode 2
A large current constant current circuit consisting of 8 is provided. In addition,
The current flowing through these constant current circuits is determined by the resistor 21 and the resistor 25, respectively. Here, terminal 2
9 is a signal 111 PI and a signal ゛○'' indicating current supply and current supply stop, respectively, from the charging control circuit 9.
is applied, and when the signal 111 JT is applied, transistors 30 and 31 are turned on, and current flows through the small current constant current circuit and the large current constant current circuit, respectively. Also, when the signal 110 PI is applied, each transistor turns on. 30 and 31 are each turned off, and no current flows through each constant current circuit. On the other hand, signals "0" and "1" indicating activation and non-operation of the main circuit 5 are applied from the determination circuit 10 to the terminal 32, and when a signal "1n" indicating non-operation is applied, the transistor 33 is turned on. Since the base of transistor 31 is grounded, transistor 31 is turned off and no current flows through the large current constant current circuit.

In this way, in this embodiment, when the main circuit 5 of the electronic device is operating, the secondary battery 8 is gradually charged, so only the main circuit 5 generates heat, and the main circuit 5 is not operating. If not, only the charging current supply circuit 6 generates heat because the secondary battery 8 is rapidly charged. Therefore, both the main circuit 5 and the charging current supply circuit 6 do not generate heat at the same time, and the electronic device generates only a small amount of heat.

In the embodiment, whether or not the main circuit 5 is operating is determined based on the potential on the input side of the main circuit 5, but the invention is not limited to this. The determination may be made based on whether the switch 4 is on or off. In addition, although the completion of charging is detected by checking whether the terminal voltage of the secondary battery has reached a set value, other methods such as monitoring the direction of change in terminal voltage over time or monitoring the surface temperature of the battery may be used. It may be detected by

〔Effect of the invention〕

As explained above, according to the present invention, the secondary battery is gradually charged when the electronic device is in operation, and the secondary battery is rapidly charged when the electronic device is not in operation, so that both the electronic device and the charging circuit can be charged. It is possible to provide a charging device for a secondary battery in an electronic separate device that does not generate heat at the same time.

[Brief explanation of the drawing]

FIG. 1 is a block diagram showing an embodiment of the charging device according to the present invention, FIG. 2 is a circuit diagram showing the configuration of a charging current supply circuit in the embodiment shown in FIG. 1, and FIG. 3 is a conventional charging device. FIG. 2 is a block diagram showing the device. 1...Input terminal, 2.3.4...Switch, 5
...Main circuit, 6.Charging current supply circuit, 7.
...Diode, 8...Secondary battery, 9...Charging suppression circuit, 10...Judgment circuit Fig. 1 Fig. 3

Claims (1)

[Scope of Claims] A charging device for a secondary battery in an electronic device operated by an external power source or a secondary battery charged by power supply from the external power source, comprising: determining whether or not the electronic device is operating. and a determining means for gradually charging the secondary battery by supplying power from the external power source when the determining means determines that the electronic device is operating, and the determining means causing the electronic device to operate. 1. A charging device for a secondary battery in an electronic device, comprising: a charging means for rapidly charging the secondary battery by supplying power from the external power source when it is determined that the secondary battery is not loaded.