JP2008079355A - Electronic apparatus - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an electronic apparatus which can continuously prevent heat generation caused by an overcurrent and the breakage of a circuit without the need for the replacement of a fuse or the like, can suppress a circuit loss, and is high in reliability and usability. <P>SOLUTION: The electronic apparatus 1 comprises a power supply 2 and the circuits 3a, 3b and 3c connected to the power supply 2. The electronic apparatus also comprises: an induction current detection part 7 which comprises a switch 4 arranged between the power supply 2 and the circuit 3c, and switching a state between the power supply 2 and the circuit 3c to a connected state or a disconnected state, and detects a current induced by a current between the power supply 2 and the circuit 3c; and a control part 5 which controls the switch 4 to the disconnected state according to a detection value from the induction current detection part 7. <P>COPYRIGHT: (C)2008,JPO&INPIT

Description

  The present invention relates to an electronic device, and more particularly to an electronic device including a protection circuit against overcurrent.

  When a circuit is short-circuited due to a circuit failure in the electronic device or water entering the electronic device, an overcurrent is generated in the circuit, which may cause a malfunction or heat generation due to circuit damage. As a countermeasure against this, conventionally, a method of interrupting the current by connecting a fuse to a circuit in which an overcurrent may occur is used.

  Further, as a structure of an electronic device provided with a protection circuit against overcurrent, a structure as shown in Patent Document 1 is used. Specifically, a current detection unit and a burst switch are provided between the transmission amplifier circuit and the battery. Furthermore, a control unit is connected to the current detection unit, and a burst control unit is provided between the control unit and the burst switch. When the current detection unit detects an overcurrent flowing to the transmission amplifier circuit, the current detection unit sends the information to the control unit. Upon receiving this information, the control unit controls the burst control unit to turn off the burst switch.

JP-A-11-88226

  However, as described above, the method of cutting off the current by inserting a fuse into a circuit that may generate an overcurrent is a protection circuit that must be replaced again if the fuse is blown once the overcurrent flows. The problem that it cannot be used as a problem arises.

  Moreover, since the structure shown in Patent Document 1 inputs the current detection unit in series with the circuit, there arises a problem that a voltage drop corresponding to the series resistance occurs.

  For this reason, the present invention improves the inconveniences of the above conventional example, and in particular, this eliminates the need for replacement of fuses and the like, and can continue to prevent heat generation and circuit breakage due to overcurrent, as well as circuit loss. It is an object of the present invention to provide a highly reliable and convenient electronic device.

  Therefore, an electronic device according to one embodiment of the present invention is an electronic device including a power source and a circuit connected to the power source, and is disposed between the power source and the circuit, and the power source and the circuit are connected or disconnected. A switch for switching to a state, an induction current detection unit for detecting a current induced by a current between a power source and a circuit, and a control unit for controlling the switch to a cut-off state according to a detection value from the induction current detection unit It is characterized by that. According to such a configuration, when a current flows between the power source and the circuit, a magnetic field is generated around the current. When the current between the power source and the circuit increases or decreases, the magnetic flux passing through the induced current detection unit also increases or decreases at the same time, so that a current is induced in the induction current detection unit by electromagnetic induction. And according to the detected value by the induction current detection part, a control part controls a switch to the interruption | blocking state, and interrupts | blocks the electric current between a power supply and a circuit. As a result, even if a current that causes circuit damage between the power supply and the circuit due to a short circuit or failure of the circuit occurs, the current between the power supply and the circuit can be cut off without using a fuse, etc. Can be prevented. Further, since the control unit controls the switch to switch the connection state or the cutoff state as needed, it can be used continuously without requiring replacement like a fuse. Furthermore, since the current is detected without connecting the induction current detection unit between the power supply and the circuit, it is possible to prevent a circuit loss such as a voltage drop corresponding to the series resistance due to the series connection.

  And the induction current detection part was arranged in parallel with the connection line between a power supply and a circuit, It is characterized by the above-mentioned. According to such a configuration, since the induction current detection unit is arranged in parallel on the connection line between the power supply and the circuit, a current induced in accordance with a change in the current between the power supply and the circuit can be obtained with certainty.

  Further, the present invention is characterized in that the induced current detection unit is provided in the vicinity of the connection line between the power source and the circuit. According to such a configuration, since the induced current detection unit is provided close to the connection line between the power source and the circuit, the magnetic flux due to the current between the target power source and the circuit is generated even if a plurality of circuits are provided in the electronic device. , It can be reliably passed through the induced current detector. Therefore, a current induced with a change in current between the target power supply and the circuit can be obtained more reliably.

  Further, when the detected value by the induced current detection unit exceeds a preset value higher than the value at the time of starting the electronic device, the control unit controls the switch to a cut-off state. . As a result, when the detection value by the induced current detection unit is higher than the value at the time of starting the electronic device and exceeds a preset value, the control unit controls the switch to the cut-off state. The Therefore, only when the current between the power supply and the circuit changes from the current in the normal use state to a current that causes circuit breakage or the like, the current between the power supply and the circuit can be cut off to prevent heat generation or circuit breakage.

  In addition, a timer is provided to measure the duration of the switch shutoff state, and the control unit controls the switch to the shutoff state and simultaneously activates the timer. After the preset time is measured by the timer, the switch is connected. It is characterized by controlling. As a result, the switch cuts off the current between the power source and the circuit, and after the preset time has elapsed, the power source and the circuit are connected again. Therefore, when the current between the power source and the circuit is returned to the normal state, the electronic device can be automatically restored to the use state.

  According to another aspect of the present invention, a method for controlling an electronic device including a power source and a circuit connected to the power source includes a first step of detecting a current induced by the current between the power source and the circuit, And a second step of controlling a switch that is provided between the power source and the circuit and switches between the power source and the circuit to a connected state or a cut-off state in accordance with the detected value.

  Moreover, after the 2nd process, it has the 3rd process of measuring the continuation time of the interruption | blocking state of a switch, and controlling a switch to a connection state, after preset time passes.

  Furthermore, the present invention also provides a program for causing an electronic device control device to execute the above method.

  Even if the method and the program of the invention are used, the above-described electronic device operates in the same manner, so that the object of the invention can be achieved.

  Since the present invention is configured and functions as described above, according to this, the current induced by the current between the power source and the circuit is detected, and the current between the power source and the circuit is connected according to the detected value at this time. Can be blocked. Therefore, it is possible to continuously prevent heat generation and circuit damage due to overcurrent without requiring replacement of fuses, etc., and also to prevent circuit loss, reliability of electronic equipment, convenience, and design It has an unprecedented excellent effect that the degree of freedom can be improved.

  According to the present invention, the induced current detection unit detects a current induced by a current between the power source and the circuit, and the control unit switches the switch to a connected state or a cut-off state according to a detection value by the induced current detection unit. It has the characteristics. Hereinafter, specific configurations and operations will be described with reference to examples.

  A first embodiment of the present invention will be described with reference to FIGS. FIG. 1 is a block diagram illustrating a configuration of an electronic device according to the present embodiment. FIG. 2 is a configuration diagram illustrating a configuration of the induced current detection unit. FIG. 3 is a functional block diagram illustrating the configuration of the control unit. FIG. 4 is an explanatory diagram illustrating the operation of the induced current detection unit when the current between the power source and the circuit increases. FIG. 5 is an explanatory diagram for explaining the operation of the induced current detector when the current between the power source and the circuit decreases. FIG. 6 is a flowchart for explaining the operation of the electronic apparatus.

[Constitution]
The electronic device 1 in the present embodiment is, for example, a mobile phone. As shown in FIG. 1, the internal configuration of the electronic apparatus 1 is connected to a power source 2 and circuits 3a, 3b, and 3c, and a switch 4 is connected between the power source 2 and the circuit 3c. Further, the switch 4 is connected to a control unit 5, and the control unit 5 is connected to an amplifier circuit 6. The amplifier circuit 6 is connected to the induced current detector 7. In this embodiment, the case where the electronic apparatus 1 is a mobile phone will be described. However, this is only an example, and a personal computer, a PHS (Personal Handyphone)
System), a fixed telephone terminal, and a PDA (Personal Digital Assistance). Hereinafter, each configuration will be described in detail.

  The power source 2 is a battery that supplies power to the circuit, and is connected to the circuits 3a, 3b, and 3c via a pattern 81 to be described later.

  The patterns (connection lines) 81 and 82 are used when connecting between the electronic components and between the power source and the circuit, and connect between the power source 2 and the circuit 3c. Moreover, it is used also in the inside of the induced current detection part 7 mentioned later.

  The circuits 3 a, 3 b, and 3 c realize each function in the electronic device 1, and the circuits 3 a to 3 c are connected to the power supply 2. The circuits 3a to 3c are grounded, and the switch 4 is connected only between the power supply 2 and the circuit 3c. The switch 4 is connected in series between the power source 2 and the circuit 3c, and switches between the power source 2 and the circuit 3c to a connected state or a cut-off state based on a command from a switch control processing unit 51 described later. Specifically, when an overcurrent occurs between the power supply 2 and the circuit 3c, the switch 4 receives a command from the switch control processing unit 51 and switches between the power supply 2 and the circuit 3c to a cut-off state. In the present embodiment, the case where the electronic apparatus 1 includes three circuits has been described. However, this is an example, and the number of circuits is not limited to three.

  The induced current detection unit 7 is a detection circuit that detects a current induced by electromagnetic induction based on the current of the pattern 81 connecting the power supply 2 and the circuit 3c. The induced current detection unit 7 includes a pattern 82 and a resistor 9. One end of the pattern 82 is grounded (GND), and the other end is connected to an amplifier circuit 6 described later. Specifically, as shown in FIG. 2, the pattern 82 is arranged in parallel and close to the pattern 81 connecting the power source 2 and the switch 4, and is formed to be folded back to the circuit 3c side on the power source 2 side. Has been. The switch 4 side which is one end of the pattern 82 is grounded, and the other end side which is turned back is connected to the amplifier circuit 6. A resistor 9 is disposed between one end side and the other end side of the pattern 82. Thereby, as shown in FIGS. 4 to 5, the induced current detection unit 7 can detect the current induced by the electromagnetic induction by the magnetic field B generated in the pattern 81. In addition, although the present Example demonstrated the case where the induced current detection part 7 was arrange | positioned in parallel and close to the pattern 81 which connects between the power supply 2 and the switch 4, when it arrange | positions in parallel and close It is not limited. Any place where the current can be induced by electromagnetic induction by the current of the pattern 81 connecting the power source 2 and the circuit 3c may be used.

  The control unit 5 is, for example, a CPU that controls the electronic device, and is provided inside the electronic device 1. As shown in FIG. 3, a switch control processing unit 51 is constructed in the control unit 5 by incorporating a program. The control unit 5 is connected to an amplifier circuit 6 and a switch 4 which will be described later.

  The switch control processing unit 51 sends a command to the switch 4 according to a voltage value V from an amplifier 6 described later. The voltage value V is a value obtained by amplifying the voltage value detected at the point b of the resistor 9 connected to the pattern 82 by the amplifier circuit 6 when the current I1 between the power source 2 and the circuit 3c changes. is there. When the voltage value V input to the switch control processing unit 51 exceeds a preset value Vth that is higher than the value at the time of starting the electronic device 1 (V ≧ Vth), the switch 4 is turned on. Sends a command to switch to the shut-off state. In the present embodiment, the voltage value Vth that can be set in advance is set to a value at which the current between the power supply 2 and the circuit 3c is overcurrent (current that causes circuit breakage) as compared with the normal use state. is doing. Thereby, only when the input voltage value V exceeds the value Vth at the time of occurrence of the overcurrent, the switch 4 can be controlled to be in the cutoff state, and the current between the power source and the circuit can be cut off.

  The amplifier circuit 6 obtains an output electric signal having a larger electric power than the inputted electric signal. The amplifier circuit 6 is connected between the induced current detection unit 7 and the control unit 5. Then, the power from the induced current detection unit 7 is amplified and sent to the control unit 5.

[Operation]
Next, the operation of the electronic apparatus in this embodiment will be described with reference to FIGS. In the initial state of the electronic device 1, the switch 4 is assumed to be in a connected state. First, the electronic device 1 is activated, and a current flows from the power source 2 to the circuits 3a, 3b, and 3c (step S1). At this time, as shown in FIGS. 4 to 5, in the pattern 81 connecting the power source 2 and the switch 4, the current I1 flows in the direction of the block arrow, and the magnetic field B is generated in the direction of the line arrow. When the current I1 increases, the magnetic flux passing therethrough increases in the pattern 82. Therefore, the current I2 flows in a direction (in the direction of the block arrow in FIG. 4) that prevents the magnetic flux from increasing due to electromagnetic induction. Then, when the current I1 decreases, the magnetic flux passing through the pattern 82 decreases, so that the current I2 flows in a direction that prevents the magnetic flux from decreasing (the direction of the block arrow in FIG. 5). Then, a voltage value corresponding to a change in the current I1 is detected at a point b of the resistor 9 connected to the pattern 82. Then, the amplified voltage value V is detected by the switch control processing unit 51 through the amplifier circuit 6 (step S2). Here, when the electronic device 1 is activated, the voltage value V input to the switch control processing unit 51 is lower (V <Vth) than the value Vth when the overcurrent occurs (in step S3). (No determination), the switch 4 remains connected, and the circuit 3c is in the operating state (No determination in step S5).

  Subsequently, when the current between the power supply 2 and the circuit 3c increases and an overcurrent flows, the input voltage value V is detected (step S2). When compared with the set voltage value Vth, V is greater than Vth. Is higher (V ≧ Vth), and a command to cut off is sent from the switch control processing unit 51 to the switch 4 (positive determination in step S3). Then, the switch 4 interrupts the current between the power source 2 and the circuit 3c (step S4).

  Next, when the electronic device 1 is started again after the current between the power source 2 and the circuit 3c is cut off by the above operation (step S1), the voltage value V is detected by the switch control processing unit 51. (Step S2). Since V is not determined to be higher than Vth (negative determination in step S3), the power source 2 and the circuit 3c are disconnected during the previous use (positive determination in step S5). A command to connect to the switch 4 is sent from 51. Then, the switch 4 connects between the power supply 2 and the circuit 3c (step S6). As a result, among the circuits 3a, 3b, and 3c connected to the power source 2, only the current between the power source 2 and the circuit 3c, which is a protection target from overcurrent, can be cut off, and replacement such as a fuse is necessary. It can be used continuously.

  In this embodiment, the case where the switch 4 is connected only between the power source 2 and the circuit 3c has been described. However, this is an example, and the switch 4 is connected between the power source 2 and the circuits 3a, 3b, and 3c. The switches 4 may be connected and controlled by the control unit 5.

  Next, a second embodiment of the present invention will be described with reference to FIGS. FIG. 7 is a block diagram illustrating the configuration of the electronic device according to the present embodiment. FIG. 8 is a functional block diagram showing the configuration of the control unit. FIG. 9 is a flowchart for explaining the operation of the electronic device. The present embodiment employs substantially the same configuration as that of the first embodiment described above, but differs in that the timer 10 is connected to the control unit 5 and that the timer control processing unit 52 is constructed in the control unit 5.

  The electronic device 21 in the present embodiment is, for example, a mobile phone. As shown in FIG. 7, the internal configuration of the electronic device 21 is such that a power source 2 and circuits 3a, 3b, 3c are connected, and a switch 4 is connected between the power source 2 and the circuit 3c. Further, the switch 4 is connected to a control unit 5, and the control unit 5 is connected to an amplifier circuit 6 and a timer 10. The amplifier circuit 6 is connected to the induced current detector 7. Hereinafter, the configuration different from that of the first embodiment will be described in detail with reference to FIGS.

  The control unit 5 is, for example, a CPU that controls the electronic device, and is provided inside the electronic device 21. As shown in FIG. 8, a switch control processing unit 51 and a timer control processing unit 52 are constructed in the control unit 5 by incorporating a program. Further, the control unit 5 is connected to the amplifier circuit 6, the switch 4, and a timer 10 described later.

  The switch control processing unit 51 sends a command to the switch 4 described later according to the voltage value V from the amplifier circuit 6. The voltage value V is a value obtained by amplifying the voltage value detected at the point b of the resistor 9 connected to the pattern 82 by the amplifier circuit 6 when the current I1 between the power source 2 and the circuit 3c changes. is there. When the voltage value V input to the switch control processing unit 51 exceeds a preset value Vth that is higher than the value at the time of activation of the electronic device 21 (V ≧ Vth), the switch 4 is turned on. Sends a command to switch to the shut-off state. In the present embodiment, the voltage value Vth that can be set in advance is set to a value at which the current between the power supply 2 and the circuit 3c is overcurrent (current that causes circuit breakage) as compared with the normal use state. is doing. Further, in response to a command from a timer control processing unit 52 described later, a command for switching to the connected state is sent to the switch 4 again. Thereby, when the electric current between the power supply 2 and the circuit 3c has returned to the normal state, the electronic device 21 can be automatically restored to the use state.

  The timer control processing unit 52 sends a measurement start or measurement end command to the timer 10 described later, or receives a measurement time signal from the timer 10. In addition, the measurement time by the timer 10 can be set in advance, and in this embodiment, a problem occurring between the power source 2 and the circuit 3c is predicted, and the time required for solving this problem is set as the measurement time. ing. When the measurement time signal is received from the timer 10, it is determined whether or not the set time has elapsed. If the set time has elapsed, the switch control processing unit 51 is brought into the connected state. Send a command to control.

  The timer 10 is connected to the control unit 5. In addition, the timer 10 receives a command from the timer control processing unit 52, measures the duration time of the shut-off state of the switch 4, and sends a measurement time signal to the timer control processing unit 52. When the set time elapses, a measurement end command is received from the timer control processing unit 52, and the timer 10 ends the measurement.

  The switch 4 is connected in series between the power source 2 and the circuit 3c, and switches between the power source 2 and the circuit 3c to a connected state or a cut-off state based on a command from the switch control processing unit 51. Specifically, when an overcurrent occurs between the power supply 2 and the circuit 3c, the switch 4 receives a command from the switch control processing unit 51 and switches between the power supply 2 and the circuit 3c to a cut-off state. Then, when the measurement by the timer 10 passes the set time, a command is received from the switch control processing unit 51, and the power supply 2 and the circuit 3c are switched to the connected state again.

  Next, the operation in the embodiment will be described with reference to FIG. In the initial state of the electronic device 21, the switch 4 is in a connected state. First, the electronic device 21 is activated, and a current flows from the power supply 2 to the circuits 3a, 3b, 3c (step S21). Then, a voltage value corresponding to a change in the current I1 is detected at a point b of the resistor 9 connected to the pattern 82. Then, the amplified voltage value V is detected by the switch control processing unit 51 through the amplifier circuit 6 (step S22). Here, when the electronic device 1 is activated, the voltage value V input to the switch control processing unit 51 is lower (V <Vth) than the value Vth at the time of occurrence of overcurrent (in step S23). (No determination), the switch 4 remains connected, and the circuit 3c is in an operating state (No determination in step S29).

  Subsequently, when the current between the power source 2 and the circuit 3c increases and an overcurrent flows, the input voltage value V is detected (step S22), and compared with the set voltage value Vth, V is greater than Vth. Is higher (V ≧ Vth), and a command to cut off is sent from the switch control processing unit 51 to the switch 4 (Yes determination in step S23). At this time, a measurement start command is sent to the timer 10, and the timer 10 starts measurement (step S24). At the same time, a command to cut off the switch 4 is sent from the switch control processing unit 51, and the switch 4 cuts off the current between the power source 2 and the circuit 3c (step S25). When the timer control processing unit 52 determines that the measurement time of the timer 10 has passed the set time (positive determination at step S26), the timer 10 is instructed to end the measurement, and at the same time the switch A command is sent to the control processing unit 51 to connect the switch 4. Then, the timer 10 that has received a command to end the measurement ends the measurement (step S27), and the switch control processing unit 51 that has received the command to connect the switch 4 sends a command to connect to the switch 4 to supply power 2 And the circuit 3c is connected again (step S28).

  Next, when the current between the power source 2 and the circuit 3c is interrupted, when the electronic device 21 is activated again (step S21), the switch control processing unit 51 detects the voltage value V (step S22). . Since V is not determined to be higher than Vth (negative determination in step S23) and the power source 2 and the circuit 3c are disconnected (positive determination in step S29), the switch control processing unit 51 to the switch 4 A command to connect to is sent. Then, the switch 4 connects between the power supply 2 and the circuit 3c (step S30).

  Thereby, even when an overcurrent flows between the power source 2 and the circuit 3c and the power source 2 and the circuit 3c are interrupted, the power source 2 and the circuit 3c are automatically connected after the measurement time of the timer 10 has passed the set time. The circuits 3c can be connected. If the state in which the overcurrent flows between the power supply 2 and the circuit 3c is not improved after the set time has elapsed, the voltage value due to the overcurrent is input again, and the power supply 2 and the circuit 3c are disconnected. Damage can be prevented continuously.

  The present invention can be used for an electronic device having a power source and a circuit, and has industrial applicability.

1 is a block diagram illustrating a configuration of an electronic device according to a first embodiment. FIG. 2 is a configuration diagram illustrating a configuration of an induced current detection unit according to the first embodiment. FIG. 3 is a functional block diagram illustrating a configuration of a control unit according to the first embodiment. It is explanatory drawing explaining operation | movement of the induced current detection part when the electric current between a power supply and a circuit increases. It is explanatory drawing explaining operation | movement of the induced current detection part when the electric current between a power supply and a circuit reduces. 6 is a flowchart for explaining the operation of the electronic device according to the first embodiment. FIG. 10 is a block diagram illustrating a configuration of an electronic device according to a second embodiment. FIG. 10 is a functional block diagram illustrating a configuration of a control unit according to a second embodiment. 6 is a flowchart illustrating an operation of an electronic device according to a second embodiment.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1,21 Electronic device 2 Power supply 3a, 3b, 3c Circuit 4 Switch 5 Control part 6 Amplifying circuit 7 Inductive current detection part 81, 82 Pattern (connection line)
9 Resistance 10 Timer 51 Switch control processing unit 52 Timer control processing unit

Claims (8)

An electronic device comprising a power source and a circuit connected to the power source,
The switch is disposed between the power source and the circuit, and includes a switch for switching the power source and the circuit to a connected state or a disconnected state,
An induction current detection unit that detects a current induced by a current between the power source and the circuit, and a control unit that controls the switch to a cut-off state according to a detection value from the induction current detection unit, An electronic device characterized by that.   The electronic device according to claim 1, wherein the induced current detection unit is arranged in parallel on a connection line between the power source and the circuit.   The electronic device according to claim 2, wherein the induced current detection unit is provided in proximity to a connection line between the power source and the circuit.   The control unit controls the switch to a cut-off state when a value detected by the induced current detection unit exceeds a preset value higher than a value at the time of starting the electronic device. The electronic device according to claim 1, 2, or 3.   A timer for measuring the duration of the switch off state is provided, and the control unit operates the timer at the same time as controlling the switch to the off state, and after the time preset by the timer is measured, 5. The electronic device according to claim 1, wherein the switch is controlled to be connected. A method for controlling an electronic device comprising a power source and a circuit connected to the power source,
A first step of detecting a current induced by a current between the power source and the circuit;
A second step of controlling a switch, which is provided between the power source and the circuit, and switches between the power source and the circuit to a connected state or a cut-off state according to the detected value, to a cut-off state;
A method for controlling an electronic apparatus, comprising:   After the second step, the switch has a third step of measuring the duration of the cut-off state of the switch and controlling the switch to the connected state after a preset time has elapsed. The method for controlling an electronic device according to claim 6. In a control device for an electronic device comprising a power source and a circuit connected to the power source,
Depending on the value detected by the induced current detector that detects the current induced by the current between the power source and the circuit, the power source and the circuit provided between the power source and the circuit are connected or disconnected. A step of controlling the switch to be switched to a shut-off state,
A program for running

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