JPH10105292A - Portable information terminal device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To enable charging without special charging peripheral equipment and to free the exchanges of battery and the complicatedness of charging by providing a charging circuit that charges an internal secondary battery when a device body is connected to a host machine. SOLUTION: When a portable information terminal device 1 is connected to a host device 2, the device 1 transmits and receives data via a transmitting line 17B and a receiving line 17C and is a].so provided with power supply from the device 2 via a power supply line 17A. A charging circuit 11 of the device l detects power voltage of the line 17A, and when the voltage is equal to or higher than a fixed value, e.g. 5V, it properly controls charging current and charging time, etc., and charges secondary battery 12. Also, during charging, when the power voltage of the line 17A falls to be lower than 4.8V, the charging to the battery 12 is forcedly stopped. Therefore, for instance, when the device 2 is driven by battery, it is never taken place that the battery is used up by charging the battery 12 and damages the drive of the device 2 itself.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a portable information terminal device having a built-in battery and connectable to a host device.

[0002]

2. Description of the Related Art Conventionally, as a portable information terminal device connectable to a host device such as a personal computer, for example,
ChipCard and the like manufactured by IBM Japan are known.

[0003]

However, in a conventional portable information terminal device such as the above-mentioned product, a primary battery such as a zinc-air battery is used as a power source, and the battery is periodically replaced. I had to.

[0004] Even when a secondary battery is built in, there is an inconvenience that the user must prepare a dedicated peripheral device such as a dedicated charging adapter and connect the portable information terminal device to the peripheral device for charging. Was.

Further, when the host device is a portable device such as a notebook personal computer, which is driven by a battery, and especially when the remaining battery power is very small, both the host device and the portable information terminal device are used. Both had the problem of being unusable.

SUMMARY OF THE INVENTION The present invention has been made to solve the above-described problems. The present invention eliminates the complexity of battery replacement and charging, and eliminates the need for special charging peripherals. It is an object of the present invention to provide a portable information terminal device that can perform charging and that can control charging of a built-in battery according to a power supply state of a higher-level device.

[0007]

In order to achieve this object, a portable information terminal device according to the first aspect of the present invention comprises:
A secondary battery is built-in, and a charging circuit is provided for charging the secondary battery when the main body of the portable information terminal device is connected to a host device.

[0008] The portable information terminal device having the above configuration,
When used alone, it operates with a built-in secondary battery, and when the portable information terminal device is connected to a higher-level device for data transmission, etc., a secondary battery is provided by a charging circuit provided on the portable information terminal device side. The battery is charged.

The portable information terminal device according to a second aspect of the present invention includes, as the charging circuit, control means for controlling whether or not to charge the secondary battery according to a power supply voltage supplied from the higher-level device. It is characterized by using the following.

[0010] The portable information terminal device having the above configuration is
When used alone, it operates with a built-in secondary battery, and when the main body of the portable information terminal device is connected to a higher-level device for transmitting information or the like, the control means provided in the charging circuit of the portable information terminal device side The power supply voltage supplied from the host device is detected, and the charging circuit is controlled so as to charge the secondary battery only when the voltage is higher than a certain value.

[0011]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS One embodiment of the present invention will be described below with reference to the drawings.

FIG. 1 is an external view showing a state in which a portable information terminal device 1 of the present embodiment is connected to a host device 2 such as a personal computer.

The portable information terminal device 1 is inserted through an opening formed on one side surface of the host device 2, and is connected via a connector device 17 disposed at the back of the opening.
Both are mechanically and electrically connected.

FIG. 2 is a block diagram showing an outline of a circuit configuration when the portable information terminal device 1 of the present embodiment and the host device 2 are connected.

The portable information terminal device 1 includes a secondary battery 12,
A charging circuit 11 for controlling charging of the secondary battery 12;
It comprises a PU circuit 13, a memory circuit 14, a display device 15 composed of a liquid crystal display panel or the like, an input device 16 composed of a touch key panel or the like, and a connector device 17.

As the secondary battery 12, for example, a nickel metal hydride battery or the like can be used.

The connector device 17 is a portable information terminal device 1
Is a member for connecting the power supply line 17A, the transmission line 17B, and the reception line 17C to each other by physically connecting them by engagement or fitting.

When the portable information terminal device 1 is connected to the host device 2, the portable information terminal device 1 transmits and receives data via the transmission line 17B and the reception line 17C, and receives the data from the host device 2 via the power line 17A. Power is supplied to the portable information terminal device 1.

As shown in FIG. 3, the charging circuit 11 is an electronic circuit comprising a transistor 5, a control circuit 6 as control means, and the like, and supplies the power supply voltage of the power supply line 17A to the control circuit 6. When the voltage is equal to or higher than a predetermined value, the charging current, charging time, and the like are appropriately controlled to charge the secondary battery 12.

Specifically, only when the power supply voltage of the power supply line 17A is, for example, 5 V or more, the control circuit 6
Applies a predetermined voltage to the base electrode of the transistor 5 so that the power supply voltage is applied to the secondary battery 12,
The charging of the secondary battery 12 is started, and when the secondary battery 12 is fully charged by a timer or the like provided in the control circuit 6, a predetermined voltage is applied to the base electrode of the transistor 5 to terminate the charging. Let it.

When the portable information terminal device 1 is disconnected from the host device 2, the portable information terminal device 1 operates with the charged secondary battery 12.

When the power supply voltage of the power supply line 17A decreases during charging and becomes lower than 4.8V, the control circuit 6
Applies a predetermined voltage to the base electrode of the transistor 5 so as to forcibly stop charging the secondary battery 12.

As described above, the control circuit 6 controls the charging of the secondary battery 12 in accordance with the power supply voltage of the power supply line 17A.
In the case of a portable notebook or sub-notebook personal computer as shown in FIG. 1, which is driven by a battery without using an AC adapter, in particular, when the remaining amount of the battery is very small, To the secondary battery 12
Of the host device 2 itself.

In the portable information terminal device 1 according to the present embodiment having the above-described configuration, for example, the portable information terminal device is configured such that a power supply line in an arbitrary interface such as PCMCIA is used as a charging power source as it is. 1 can be configured, so that there is no need to modify the host device 2 side or attach a special mechanism. Therefore, it is possible to correspond to higher-level devices of different manufacturers with the same interface.
The secondary battery 12 can be charged.

The circuit for charging the secondary battery 12 is self-contained on the portable information terminal device 1 side.
For example, since the information such as the remaining amount of the secondary battery 12 and the charging history can be stored in the portable information terminal device 1 by storing it in the memory circuit 14, the attachment and detachment of the portable information terminal device 1 can be repeated, Even when the portable information terminal device 1 is connected to another host device, it is possible to always monitor information such as the remaining amount of the secondary battery 12 on the connected host device.

The memory circuit 14 is a circuit that stores and holds the above-mentioned predetermined program and also stores and holds data input by the user to the portable information terminal device 1 itself or data transferred from the host device 2.

The display device 15 comprises a liquid crystal display panel or the like.
Display characters, figures, etc. as necessary.

The input device 16 comprises a touch key panel or the like, and is used by a user to input data or the like.

The CPU circuit 13 is a central processing circuit comprising a one-chip microcomputer, executes a predetermined program, and realizes a function as an information terminal device.

That is, the CPU circuit 13 accumulates or reads data from the memory circuit 14 and the host device 2 according to data, commands, and the like input by the user using the input device 15. The data and the like are displayed on the display device 15 to function as an information terminal device.

As described above, according to the present embodiment, the complexity of battery replacement and charging can be eliminated, and the built-in battery can be charged without preparing a special charging peripheral device. In addition, it is possible to provide a portable information terminal device capable of controlling charging of a built-in battery according to the state of the power supply of a higher-level device.

The present invention is not limited to the above-described embodiment, and various changes can be made without departing from the gist of the present invention.

For example, in the above-described embodiment, a circuit combining a timer and a transistor is used as a charging circuit, but a voltage drop is detected while monitoring a voltage by combining a CPU or the like with an A / D converter. A rapid charging circuit based on the so-called -ΔV method in which charging is turned off by using a so-called -ΔV method may be used.

In the above embodiment, only the secondary battery is used. However, in a low-temperature environment, the discharge characteristics of the secondary battery may be reduced. Good. At this time, control may be performed so that the primary battery is used only when the terminal voltage of the primary battery is higher than that of the secondary battery.

[0035]

As is clear from the above description,
According to the portable information terminal device according to claim 1 of the present invention,
The complexity of battery replacement and charging is eliminated, and the built-in battery can be charged without preparing special peripheral devices for charging.

Further, the portable information terminal device according to the second aspect eliminates the complexity of battery replacement and charging, and can charge the built-in battery without preparing a special charging peripheral device. In addition, charging of the built-in battery can be controlled according to the state of the power supply of the host device.

[Brief description of the drawings]

FIG. 1 is a diagram illustrating an appearance when a portable information terminal device and a higher-level device according to an embodiment of the present invention are connected.

FIG. 2 is a block diagram schematically showing a circuit configuration when the portable information terminal device is connected to a host device.

FIG. 3 is a block diagram schematically showing a circuit configuration of a charging circuit provided in the portable information terminal device.

[Explanation of symbols]

 REFERENCE SIGNS LIST 1 portable information terminal device 2 host device 6 control circuit 11 charging circuit 12 secondary battery 17 connector device 17A power supply line

──────────────────────────────────────────────────続 き Continued on the front page (51) Int.Cl. ⁶ Identification code FIG06F 1/00 335A

Claims (2)

[Claims] 1. A portable information terminal device having a built-in battery and connectable to a host device, wherein the battery is constituted by a secondary battery, and the portable information terminal device main body is connected to the host device when the main unit is connected to the host device. A portable information terminal device comprising a charging circuit for charging a secondary battery. 2. The charging circuit according to claim 1, wherein the charging circuit includes control means for controlling whether or not to charge the secondary battery in accordance with a power supply voltage supplied from the host device. The portable information terminal device described in the above.