JPH06311666A - Power supply device - Google Patents

Abstract

PURPOSE:To provide a power supply device wherein an external power supply can be replaced during the operation of a main body by a method wherein a built-in battery is charged by an externally attached battery. CONSTITUTION:When an adapter 2 is used as an external power supply, a main body 14 is driven and, at the same time, a built-in secondary battery 9 is charged via a charging route 7 until it is charged fully. On the other hand, when a battery is used as the external battery, the built-in secondary battery 9 is charged shallowly so that the main body 14 can be driven continuously by the built-in secondary battery during the replacement of the external power supply. Consequently, even when the drive is started by the externally attached battery when the capacity of the built-in battery is not left, the external power supply can be replaced without suspending the supply of the power supply, and the main body can be used continuously for many hours only by using the battery.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to power supply control in a word processor, personal computer or the like which has a built-in battery and always operates while holding a memory.

[0002]

2. Description of the Related Art Information equipment such as a word processor and a personal computer which can be driven by a battery and which has one built-in battery can charge the built-in battery by a power source obtained from an external power source input through an AC adapter. It is common. With this configuration, the maximum time for driving the battery is from when the battery is fully charged to when the battery is completely discharged, and there is a possibility that the battery cannot be used for a long time in a situation where it is difficult to use an AC power source.

On the other hand, there is also a configuration in which the battery power source is removable so as to prolong the driving time by the battery. For example, as disclosed in Japanese Examined Patent Publication No. 4-91629, there is one in which a built-in capacitor or a small-capacity secondary battery is charged with a removable battery for backup when replacing the removable battery. In this configuration, the backup battery is always charged while the battery is being driven, so that power loss always occurs due to charging, and the battery driving time is shortened.

[0004]

SUMMARY OF THE INVENTION In the above conventional methods,
When operating on battery power, the user should confirm in advance that the built-in battery has remaining capacity, or if the battery has multiple removable batteries, the user must not remove the remaining battery when removing the battery. I had to be aware of leaving it in. Further, in the configuration in which the backup battery is charged by the battery, the driving time may be reduced due to continuing charging.

One object of the present invention is that the user does not need to be aware of the remaining capacity of the battery at all times, the battery can be replaced any number of times without interrupting the power supply, and the external battery can be replaced with a built-in battery. An object of the present invention is to provide a power supply device that minimizes a decrease in charging efficiency by interrupting the charging of the battery by timer management.

Another object of the present invention is to provide a power supply device capable of supplying power by exclusive use of an AC adapter and an external battery via a common connector.

[0007]

Power can be supplied from either an external power source or a built-in secondary battery, and when a battery having a built-in secondary battery charging circuit is used and an external battery is used as the external power source. Also, the built-in secondary battery is charged for a certain period of time so that the power can be supplied from the built-in secondary battery when the external power supply is replaced.

[0008]

When a built-in secondary battery is completely consumed and an external battery is connected, the built-in secondary battery is charged to a fixed amount. Since the amount of charge at this time is small, there is almost no loss due to charging efficiency. When the remaining amount of the external battery becomes low, you can continue battery operation by removing the battery and replacing it with a new battery, but power is supplied by the built-in secondary battery that has already been charged to a certain amount during battery replacement. By continuing, you can replace the external battery without interrupting the drive of the device. Therefore, the user can start the use without being aware of whether or not the capacity of the built-in secondary battery remains.

Since the built-in secondary battery is charged to the full charge when the AC adapter is connected, the built-in battery can be driven for a long time by incorporating the large capacity battery.

[0010]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS FIG. 1 is a block diagram showing an embodiment of a power supply circuit according to the present invention, and FIG.
C adapter, FIG. 3 shows the structure of the external battery unit.

In FIG. 1, the external power supply connector 1 is AC.
It is a dual-purpose connector for the adapter 2 and the external battery 3, and has three terminals: a power supply route 4, an adapter / battery discrimination signal 5, and a ground 6. When the AC adapter 2 or the external battery 3 is connected, the positive side of the power source is connected to the power source route 4 and the negative side is connected to the ground 6. The signal 5 for distinguishing between the adapter and the battery is the resistance 2 when the external battery 3 is connected.
The pull-down state is set to the minus side by 2 and the pull-up state is set to the plus side by the resistor 23 when the AC adapter 2 is connected, so that the type of the external power source connected can be determined.

The regulator 10 is connected from the power supply route 4 and the built-in secondary battery 9 through switches 18 and 20, respectively, and produces an appropriate voltage for driving the main body 14 and the power supply control unit 15.

The power supply line 8 connects the output of the regulator 10 to the main body 14 and the power supply controller 15 to supply power. The charging route 7 includes a backflow prevention diode 21, a resistor 16, and a switch 19, and is connected to supply the output of the regulator to the built-in secondary battery 9. In addition,
The switches 18, 19 and 20 can be made compact and operate at high speed by using FETs.

The voltage detector 11 monitors the voltage of the built-in secondary battery 9 and outputs the result to the power controller 15. The external power supply detection unit 12 monitors the voltage of the external power supply and outputs it to the power supply control unit 15. In addition, the power supply control unit 15 is connected to the output 13 of the charging time setting timer and the signal 5 for discriminating between the adapter and the battery.

Next, the actual operation will be described.

When the external power source detection unit 12 determines that the external power source is connected, if the adapter and battery discrimination signal 5 has the same potential as the positive side 4 of the power source, the AC adapter 2 is connected and the switch 18 , 19 are closed and the built-in secondary battery 9 is fully charged. If the adapter and the battery discrimination signal 5 have the same potential as the minus side 6, it is determined that the external battery 3 is connected, and the process proceeds to the next step.

When the external battery 3 is connected, the voltage detector 11 determines from the voltage value whether the built-in secondary battery 9 has enough capacity to drive the main body 14 for a certain period of time or longer. Generally, a battery has a property that the voltage decreases as the discharge progresses, and therefore the remaining capacity can be estimated by measuring the voltage value. However, the voltage value of the battery in the open state is more likely to be affected by the ambient temperature and the like than the battery voltage in use, and if the remaining capacity is estimated only from the voltage value, the error may increase. Therefore, a storage device may be provided in the power control unit 15 to store the estimated remaining capacity value when the built-in secondary battery 9 is finally used.

When it is estimated that the capacity of the built-in secondary battery 9 is less than a certain amount, the switch 19 is closed and the external battery 3
The built-in secondary battery 9 is charged by. At this time, a loss occurs in the resistor 16 and the regulator 10 in the charging route. Further, as the charge capacity of the built-in secondary battery 9 approaches full charge, the loss in the battery 9 also increases.
The accumulation of such a loss causes the external battery 3 to be consumed unnecessarily, which shortens the battery drive time. Therefore, the charging time is minimized by the timer 13, and charging is performed so that the built-in secondary battery 9 can be driven only for the time required for exchanging the external power supply. The charging time and the driving time vary depending on the battery capacity and the usage state, but when driving is performed by 1C discharge, which discharges the entire capacity of the battery in 1 hour, a trickle charge for 10 minutes is expected to have a driving capacity of 10 seconds or more.

If the external power supply detection unit 12 determines that the external power supply is not connected or the external battery 3 is not available due to the exhaustion of the external battery 3, the switch 1
Open 8 to stop driving the external power supply. Further, when it is estimated by the voltage detection unit 11 that the main body 14 can be driven by the built-in secondary battery 9, the switch 20 is closed and the main body is driven. If the built-in secondary battery does not have enough remaining capacity,
The switch 20 is opened to stop the power supply.

When the built-in secondary battery 9 is completely discharged and there is no external power source, the main body cannot be operated in this state. When the AC adapter 2 is connected to the external power supply connector 1, the AC adapter 2 is used as in the conventional example.
The driving of the main body 14 and the charging of the built-in secondary battery 9 are started by. After the AC adapter 2 has been used for a sufficiently long time, the charging of the built-in secondary battery 9 has been completed.
The drive of the main body 14 can be continued even if the main body is removed.

When the built-in secondary battery 9 is completely discharged,
When the external battery 3 is connected without using the C adapter 2,
The driving of the main body 14 by the external battery 3 is started, and the built-in secondary battery 9 is charged for a fixed time by setting the timer 13. If it is used as it is, the external battery 3 will eventually be discharged, and it will be necessary to replace it with another external battery or the AC adapter 2. At this time, the external battery 3 has to be temporarily removed, and the power supply from the outside is interrupted. However, since the built-in secondary battery 9 is slightly charged, the power can be supplied to the main body. I can. When the external battery 3 is replaced with a new external battery, the built-in secondary battery 9 is charged for a certain period of time again by setting the timer 13, and the next time the external battery is replaced, the built-in secondary battery 9 is charged again. Power can be supplied.

FIG. 4 is a diagram showing another embodiment of the AC adapter according to the present invention, and FIG. 5 is a circuit diagram of the power supply device side. In FIG. 5, the built-in battery, charging route, and main body are omitted from the figure.

In this AC adapter, the signal 5 for discriminating between the adapter and the battery is normally at the same potential as the plus side due to the pull-up resistor 23, and the voltage or current controller 25
Operates as a constant voltage source. When the potential is set lower than the threshold voltage Vc of the comparator 24 from the outside, the output of the comparator 24 switches the voltage or current control unit 25 to a constant current source.

In FIG. 5, when the external power source detection unit 12 detects that the external power source is connected, the comparator 26
Determines whether the external power source is the AC adapter 2 or the battery 3 based on the determination signal 5 of the adapter and the battery. External power supply is AC
In the case of the adapter, the pull-up resistor 23 determines the discrimination signal 5
Becomes a potential higher than the threshold voltage Va of the comparator 26, and in the case of the battery pack 3, the pull-down resistor 22
Therefore, the potential becomes lower than Va.

When the built-in secondary battery is rapidly charged by the AC adapter, the power supply controller 15 turns on the transistor 27 to lower the discrimination signal 5 to a potential lower than Vc. As described above, the voltage or current control unit 25 in the AC adapter 2 is switched to the constant current source, and its output appears on the plus side power supply line 4. Here, by closing the switches 18 and 20, the charging current can be supplied to the built-in secondary battery 9.

By doing so, it is not necessary to incorporate a large-current constant current circuit for rapid charging, and the mounting area and heat source can be reduced.

[0027]

According to the present invention, the AC adapter and the connector of the external battery are shared, and when the external battery is connected, the internal battery is charged for a fixed time to reduce the power loss,
Since the battery is charged to full charge when the AC adapter is connected, it is possible to back up with the built-in battery when changing the external power supply and to effectively use the capacity of the external battery. Also,
By sharing the connector and providing the AC adapter with a quick charging current source, the device can be made smaller and lighter.

[Brief description of drawings]

FIG. 1 is a circuit diagram showing an embodiment of a power supply device according to the present invention.

FIG. 2 is a circuit diagram showing an embodiment of an AC adapter according to the present invention.

FIG. 3 is a circuit diagram showing an embodiment of an external battery pack according to the present invention.

FIG. 4 is a circuit diagram showing an embodiment of an AC adapter according to the present invention.

FIG. 5 is a circuit diagram showing an embodiment of a power supply device according to the present invention.

[Explanation of symbols]

 2 ... AC adapter, 3 ... External battery pack, 5 ... Adapter and battery discrimination signal, 7 ... Charging route, 9 ... Built-in secondary battery, 13 ... Timer, 22 ... Pulldown resistor, 23 ... Pullup resistor, 25 ... Constant Voltage constant voltage source.

Claims (4)

[Claims] 1. An information device, which has a secondary battery and a charging circuit inside, can be supplied with power from an external battery, and at least while the external battery is replaced when the external battery is in a usable state. A power supply device characterized in that a built-in secondary battery is charged by an external battery with a capacity sufficient to supply power enough to hold a memory. 2. A signal line is added to an external power supply unit,
A power supply device capable of determining whether the AC adapter is connected as an external power source or the battery unit is connected from the inside of the main body. 3. The external power source is connected by monitoring the power source voltage inside the main unit by pulling up the signal line for determining the type of the external power source with a resistor inside the AC adapter and pulling down the signal line inside the battery unit. 3. The power supply device according to claim 2, wherein the type of the external power source can be discriminated by the voltage level of the type discrimination signal when it is detected. 4. A signal line for discriminating between a battery unit and an AC adapter is provided, and the signal line is used as a bidirectional control line so that a signal can be sent from the power supply control unit to the AC adapter. An information processing device, characterized in that a rapid charging power source is formed in an AC adapter by switching to a constant current source when charging a built-in secondary battery.