JP3796419B2 - Terminal device - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a terminal device, and more particularly to a terminal device that charges a battery of a mobile device such as a mobile phone by a power source supplied from a host device such as a personal computer connected via a USB interface.
[0002]
[Prior art]
A mobile device such as a mobile phone uses a battery as a power source and has a small charge capacity, and therefore needs to be charged regularly. For this purpose, a dedicated charger capable of extracting a DC voltage from a commercial power source is required. Therefore, the battery cannot be charged without a commercial power supply facility or without a dedicated charger.
[0003]
On the other hand, a host machine such as a personal computer can use a commercial power source and is equipped with a battery having a relatively large capacity. For this reason, some USB interface cables connected to the host device have a built-in function so that the battery of the mobile device can be charged.
[0004]
FIG. 2 is a block diagram of a conventional mobile device and a host device connected by a USB cable that does not have a special function as described above. In FIG. 2, the mobile device 1 includes a control circuit 11, a USB interface circuit 12, a charging circuit 13, and a battery 14. The mobile device 1 and the host device 2 are connected by a USB interface cable.
[0005]
The control circuit 11 performs unique control for the mobile device 1 and also controls exchange of data with the host device 2 via the USB interface cable. Further, a DC power supply voltage is supplied from the host device 2 to the USB interface circuit 12 from the USB interface cable. This is used as a control signal via the USB interface circuit.
[0006]
The charging circuit 13 can also be charged by a DC voltage from a charger 3 provided outside.
[0007]
The current that can be supplied from the host device 2 to the mobile device 1 via the USB interface cable is defined by the USB standard. According to this, application is made regarding the power required from the mobile device 1 to the host device 2, and when applying as a high power device, the maximum is 500 mA, and when applying as a low power device, the maximum is 100 mA. It is stipulated in. When the host machine 2 is in the suspend mode as the low power consumption mode, the maximum is 500 μA. The power supply voltage supplied from the host device 2 to the mobile device 1 is regulated to about 5V.
[0008]
[Problems to be solved by the invention]
However, the mobile device 1 shown in FIG. 2 uses only the supply voltage from the host device 2 as a control signal by simply connecting the mobile device 1 and the host device 2 with a USB cable.
[0009]
Therefore, a main object of the present invention is to provide a terminal device equipped with a USB interface function that has a function of supplying power to an internal circuit or charging a battery of a mobile device by satisfying a specified value by current limiting or voltage conversion. Is to provide.
[0010]
[Means for Solving the Problems]
The present invention introduces a built-in battery, an electric circuit powered by the built-in battery, a USB port for connecting the host machine and the electric circuit, and a power supply via the USB port, and at least a part of the electric circuit And a power supply circuit for supplying power to the power supply.
[0011]
As a result, even when there is no commercial power supply facility or when there is no dedicated charger, the mobile device battery can be charged by the power supply of the host device while satisfying the charging current and charging voltage regulations. The power supply circuit may include current limiting means for limiting a power supply current to be supplied to the electric circuit.
[0012]
The power supply circuit includes voltage conversion means for converting a power supply voltage supplied to the electric circuit into a predetermined voltage.
[0013]
The electric circuit fed from the feeding circuit is a USB interface circuit connected to the USB port.
[0014]
Another invention includes a built-in battery, an electric circuit fed by the built-in battery, a USB port for connecting the host machine and the electric circuit, a feeding circuit for introducing a feeding power supply via the USB port, and a feeding circuit Alternatively, a charging circuit for charging an internal battery using an external charger as a charging power source is provided.
[0015]
Further, when the host device is in the low power consumption mode with the built-in battery being charged using the power supply circuit as a charging power source, the charging current is set to a specified value or less.
[0016]
Further, when charging the built-in battery using the power supply circuit as a charging power source, a control signal is transmitted so that the USB interface circuit connected to the USB port does not enter the low power consumption mode to the host device.
[0017]
DETAILED DESCRIPTION OF THE INVENTION
FIG. 1 is a block diagram showing an embodiment of the present invention. 1, the mobile device 1a includes a control circuit 11, a USB interface circuit 12, a charging circuit 13, and a battery 14, as in FIG. 2, and includes a current detection circuit 15, a current limiting circuit 16, A charge switching circuit 17 and a voltage conversion circuit 18 are included.
[0018]
The supply voltage from the host machine 2 is supplied to the current detection circuit 15 and the USB interface circuit 12. The current detection circuit 15 supplies the supply voltage from the host machine 2 to the control circuit 11, detects the current supplied from the host machine 2, and supplies it to the current limiting circuit 16. Based on the detected current value from the current detection circuit 15 supplied from the control circuit 11, the current limit circuit 16 limits the current amount from the host device 2 so as not to exceed the upper limit of the current value defined by the USB standard. To do. That is, if the consumption current of the USB interface circuit 12 is 20 mA and the application consumption current is 100 mA, control is performed so as not to exceed 80 mA.
[0019]
The charge switching circuit 17 is a circuit for switching the voltage input to the charging circuit 13 between the supply voltage from the host machine 2 and the voltage from the charger 3 under the control of the control circuit 11. If charging is not performed even when the power supply voltage is supplied, switching to the charger 3 is performed.
[0020]
The voltage conversion circuit 18 converts the supply voltage from the host device 2 supplied through the current detection circuit 15 and the current limiting circuit 16 into a desired voltage. Here, the desired voltage is a voltage required by a circuit in the mobile device 1a to which this voltage is supplied.
[0021]
Note that the charging circuit 13 has a function of monitoring the decrease of the battery 14.
[0022]
Next, a specific operation of one embodiment of the present invention will be described. By connecting the mobile device 1a and the host device 2 with a USB interface cable, data communication is performed between the two, and a power supply voltage is supplied from the host device 2 to the mobile device 1a. This power supply voltage is supplied to the control circuit 11 via the current detection circuit 15 and also to the USB interface circuit 12 as a control signal. The USB interface circuit 12 notifies the control circuit 11 that the host device 2 is connected in accordance with a control signal given from the host device 2.
[0023]
The control circuit 11 recognizes that the host device 2 is connected via the USB interface circuit 12 and switches the charge switching circuit 17 to the current limiting circuit 16 side to change the current detection circuit 15 and the current limiting circuit 16 from the host device 2. Is supplied to the charging circuit 13. Thereby, the charging circuit 13 charges the battery 14.
[0024]
At this time, the detected current value detected by the current detection circuit 15 is given to the control circuit 11, and the control circuit 11 determines whether the mobile device 1a is a high power device or a low power device. The current limiting circuit 16 limits the current flowing from the charging circuit 13 to the battery 14. That is, if the mobile device 1a is a high-power device, the charging current needs to be less than the maximum current. Therefore, if the detected current value exceeds the maximum current, the current limiting circuit 16 reduces the current so as to be less than that. Limit.
[0025]
Further, the voltage conversion circuit 18 converts the supplied power supply voltage so as to be a voltage required by the circuit in the mobile device 1a. Further, the USB interface circuit 12 detects whether or not the host machine 2 is in the suspension mode. When the USB interface circuit 12 detects that the host apparatus 2 is in the suspension mode, the USB interface circuit 12 gives a detection signal to the control circuit 11. In response to the detection signal, the control circuit 11 causes the charge switching circuit 17 to stop supplying the power supply voltage to the control circuit 11 via the voltage conversion circuit 18.
[0026]
The charging circuit 13 monitors the state of charge of the battery 14 and gives the result to the control circuit 11. When the battery 14 is fully charged, the control circuit 11 causes the charge switching circuit 17 to stop supplying the power supply voltage to the charging circuit 3. The USB interface circuit 12 outputs a control signal to the host device 2 so as not to enter the low power consumption mode when the battery 14 is charged by the charging circuit 13.
[0027]
As described above, according to this embodiment, even if there is no commercial power supply facility or a dedicated charger 3 is not prepared, the mobile device 1a and the host device 2 are connected by a cable, and data communication is mutually performed. The battery 14 can be charged while performing the above. Moreover, by providing the current limiting circuit 16, the supply current can be limited within the current value that the mobile device 1 a applied to the host device 2. Further, the voltage conversion circuit 18 can supply a necessary voltage to the circuit in the mobile device 1a. If the host machine 2 is in the suspension mode, the power supply to the charging circuit 13 can be cut off by the charge switching circuit 17 in order to stop the charging from the host machine 2, so that the host machine 2 enters the suspension mode. However, there is no possibility that the current exceeding the application value flows from the host device 2 to the mobile device side 1a.
[0028]
In the above-described embodiment, the mobile device 1a may be connected to the host device 2 with a USB interface cable and has a rechargeable battery, such as a mobile phone or a mobile terminal device. Applicable to any device.
[0029]
The embodiment disclosed this time should be considered as illustrative in all points and not restrictive. The scope of the present invention is defined by the terms of the claims, rather than the description above, and is intended to include any modifications within the scope and meaning equivalent to the terms of the claims.
[0030]
【The invention's effect】
As described above, according to the present invention, the supply voltage supplied from the host machine is supplied to the internal circuit or the built-in battery is charged. Even if it is not, it is possible to satisfy the regulations and operate the internal circuit of the mobile device from the host device or charge the battery.
[0031]
Further, since the power supply voltage of the circuit used only during the USB interface in the circuit in the mobile device and the power supply voltage from the host device can be covered, the battery current can be reduced.
[0032]
Furthermore, the battery can be charged while data is communicated between the host device and the mobile device via the USB interface.
[Brief description of the drawings]
FIG. 1 is a block diagram showing an embodiment of the present invention.
FIG. 2 is a block diagram of a conventional mobile device and a host device.
[Explanation of symbols]
1a Mobile device, 2 host device, 3 charger, 11 control circuit, 12 USB interface circuit, 13 charging circuit, 14 battery, 15 current detection circuit, 16 current limiting circuit, 17 charge switching circuit, 18 voltage conversion circuit.

Claims (2)

An internal battery;
An electrical circuit powered by the internal battery;
A USB port for connecting a host machine and the electric circuit;
A power supply circuit that introduces a power supply via the USB port;
A charging circuit for charging the internal battery using the power supply circuit or an external charger as a charging power source ,
A terminal device characterized in that when the host device is in a low power consumption mode in a state where the built-in battery is charged with the power supply circuit as a charging power source, a charging current is set to a specified value or less. . When a built-in battery is charged using the power supply circuit as a charging power source, a USB interface circuit connected to a USB port sends a control signal to the host machine so as not to enter a low power consumption mode. The terminal device according to claim 1 .

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