Protection circuit and charging device

Abstract

To secure the safety against leak current on a human body with a simple structure.SOLUTION: A protection circuit is between a contact positive electrode terminal that is exposed, a first contact negative electrode terminal, and a second contact negative electrode terminal, and a positive electrode terminal and a ground terminal of a power output part, and includes a P-type MOSFET, a first cable way connecting the contact positive electrode terminal and a drain terminal of the P-type MOSFET, a second cable way connecting the positive electrode terminal and the P-type MOSFET, a first N-type MOSFET, a third cable way connecting the second contact negative electrode terminal and a drain terminal of the first N-type MOSFET and grounded, a fourth cable way connecting the ground terminal and a source terminal of the first N-type MOSFET, a fifth cable way connecting the first contact negative electrode terminal and the fourth cable way through a resistor, a sixth cable way connecting a gate terminal of the P-type MOSFET and the fifth cable way between the first contact negative electrode terminal and the resistor, and a seventh cable way connecting the gate terminal of the first N-type MOSFET and the fifth cable way between the sixth cable way and the resistor.SELECTED DRAWING: Figure 1

Description

[Technical field]

[0001] The present invention relates to a protection circuit and a charging device including the same. [Background technology]

[0002] Conventionally, when charging an electronic device with a built-in secondary battery, a configuration has been adopted in which the state of the secondary battery is confirmed using three terminals before charging begins.

[0003] In a charger for charging such a secondary battery, safety measures are taken to ensure the safety of the human body against leakage current from the resulting exposed terminals (see Patent Document 1). [Prior art documents] [Patent documents]

[0004] [Patent Document 1] Japanese Patent Application Publication No. 11-178220 Summary of the Invention [Problem to be solved by the invention]

[0005] However, such a configuration requires components and circuits on the charger side for receiving information such as the voltage value and temperature of the secondary battery, resulting in a complicated configuration.

[0006] In view of the above-mentioned conventional techniques, an object of the present invention is to provide a technique capable of ensuring safety against leakage current to the human body with a simple configuration. [Means for solving the problem]

[0007] In order to solve the above problems, the present invention provides a contact positive terminal, a first contact negative terminal, and a second contact negative terminal exposed to the outside at a connector portion connected to a device including the secondary battery; a positive terminal and a ground terminal provided in a power output unit that outputs power supplied to the secondary battery via the positive contact terminal, the first negative contact terminal, and the second negative contact terminal; A protection circuit for connecting A P-type MOSFET connected between the contact positive terminal and the positive terminal; a first current path connecting the contact positive terminal and a drain terminal of the P-type MOSFET; a second current path connecting the positive terminal and a source terminal of the P-type MOSFET; a first N-type MOSFET connected between the second contact negative terminal and the ground terminal; a third current path that connects the second contact negative terminal and a drain terminal of the first N-type MOSFET and is grounded; a fourth current path connecting the ground terminal and a source terminal of the first N-type MOSFET; a fifth electric path that connects the first contact negative terminal and the fourth electric path or the second electric path via a resistor; a sixth electric path connecting the gate terminal of the P-type MOSFET and the fifth electric path between the first contact negative terminal and the resistor; a seventh current path connecting a gate terminal of the first N-type MOSFET and the fifth current path between the sixth current path and the resistor; The present invention is characterized by comprising:

[0008] According to this, even if a person touches at least any two of the contact positive terminal, the first contact negative terminal, and the second contact negative terminal that are exposed to the outside, and at least any two of the contacted terminals are electrically connected via the human body, no leakage current flows into the human body, or only a slight leakage current flows into the human body. Therefore, safety can be ensured with a simple configuration using a P-type MOSFET, a first N-type MOSFET, a second N-type MOSFET and passive components, which does not require a complex configuration such as a control unit.

[0009] In the present invention, a second N-type MOSFET connected between the second current path and the fourth current path; an eighth current path connecting a drain terminal of the second N-type MOSFET and the second current path; a ninth current path connecting a source terminal of the second N-type MOSFET and the fourth current path; a ground path that grounds a gate terminal of the second N-type MOSFET; The above configuration may be adopted.

[0010] The present invention also relates to A charging device including the protection circuit, The connector portion is characterized in that the contact positive terminal, the first contact negative terminal, and the second contact negative terminal are arranged asymmetrically.

[0011] According to this, the contact positive terminal, the first contact negative terminal, and the second contact negative terminal are arranged asymmetrically, thereby preventing connection in the wrong orientation to an electronic device having a corresponding terminal arrangement.

[0012] The present invention also provides a method for producing a semiconductor device comprising the steps of: A charging device including the protection circuit, In the connector portion, the first contact negative terminal and the second contact negative terminal are disposed symmetrically with respect to the contact positive terminal.

[0013] According to this, the first contact negative terminal and the second contact negative terminal are arranged symmetrically with respect to the first positive terminal. Therefore, even if the first contact negative terminal and the second contact negative terminal are connected inversely to the first positive terminal in an electronic device having a corresponding terminal arrangement, the charger and the electronic device can be properly electrically connected to charge the secondary battery. Effect of the Invention

[0014] According to the present invention, it is possible to ensure safety against leakage current to the human body with a simple configuration. [Brief description of the drawings]

[0015] [Figure 1] FIG. 1 is a circuit diagram of a charger according to a first embodiment. [Diagram 2] FIG. 2 is a circuit diagram illustrating a normal connection state between the charger according to the first embodiment and the electronic device. [Diagram 3] FIG. 3 is a diagram illustrating an electrical connection between the charger according to the first embodiment and a person. [Figure 4] FIG. 4 is a diagram illustrating another electrical connection between the charger and the person according to the first embodiment. [Diagram 5] FIG. 5 is a diagram illustrating another electrical connection between the charger and the person according to the first embodiment. [Figure 6] FIG. 6 is a diagram illustrating another electrical connection between the charger and the person according to the first embodiment. [Figure 7] FIG. 6 is a circuit diagram of a charger according to a modified example of the first embodiment. [Figure 8] FIG. 8 is a diagram showing the arrangement of terminals in the charger according to the embodiment. [Figure 9] FIG. 9 is a diagram showing another arrangement of terminals in the charger according to the embodiment. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0016] Hereinafter, specific embodiments of the present invention will be described with reference to the drawings.

[0017] <Example 1> An example of an embodiment of the present invention will be described below. However, unless otherwise specified, the dimensions, materials, shapes, relative positions, and the like of the components described in this example are not intended to limit the scope of the present invention to those alone.

[0018] (Charger configuration) FIG. 1 is a circuit diagram including a protection circuit 200 of a charger 100 according to a first embodiment. The charger 100 is connected to an electronic device 400 having a secondary battery and supplies power to the secondary battery. The charger 100 has a connector section 110 connected to the electronic device 400. The connector section 110 has terminals T1, T2, and T3 exposed to the outside, which are electrically connected to terminals T21, T22, and T23 on the electronic device 400 side, respectively. Here, the charger 100, the connector section 110, and the protection circuit 200 correspond to the charging device, the connector section, and the protection circuit, respectively, of the present invention. Also, the electronic device 400 corresponds to the device of the present invention. Also, the terminals T1, T2, and T3 correspond to the contact positive terminal, the first contact negative terminal, and the second contact negative terminal, respectively, of the present invention.

[0019] The protection circuit 200 is provided between the terminals T1, T2, and T3 and the positive terminal T4 and ground terminal T5 of the output unit 300. The output unit 300 is electrically connected via the protection circuit 200 and the terminals T1, T2, and T3, and outputs power to the secondary battery of the electronic device 400. The output unit 300 may be any component or circuit that can output power to the protection circuit 200 via the positive terminal T4, and may be, for example, a power conversion device such as a converter connected to a commercial power system, or a connector connected thereto. Here, the output unit 300 corresponds to the power output unit of the present invention.

[0020] The terminal T1 is connected to a drain terminal of a p-channel enhancement type metal oxide field effect transistor (p-MOSFET) Tr1 by an electric path Ln1. A resistor R1 is connected in series between the terminal T1 and the drain terminal of the p-MOSFET Tr1 in the electric path Ln1. In addition, a source terminal of the p-MOSFET Tr1 is connected to a positive terminal T4 of the output section 300 by an electric path Ln2. A fuse F is connected between the positive terminal T4 and the source terminal of the p-MOSFET Tr1 in the electric path Ln2. Here, the p-MOSFET Tr1 corresponds to the P-type MOSFET of the present invention, and the electric paths Ln1 and Ln2 correspond to the first electric path and the second electric path of the present invention, respectively.

[0021] A diode D11 is connected in parallel between the source and drain terminals of the p-MOS ET Tr1 in the forward direction from the drain terminal to the source terminal, and a bidirectional TVS diode D12 is connected in parallel between the gate and source terminals of the p-MOS ET Tr1.

[0022] The terminal T3 is connected to the drain terminal of an n-channel enhancement type MOSFET (n-MOSFET) Tr2 by an electric path Ln3. A resistor R2 is connected in series to the electric path Ln3 between the terminal T3 and the drain terminal of the n-MOSFET Tr2. The source terminal of the n-MOSFET Tr2 is connected to a ground terminal T5 of the output section 300 by an electric path Ln4. Here, the n-MOSFET Tr2 corresponds to the first N-type MOSFET of the present invention. The electric paths Ln3 and Ln4 correspond to the third and fourth electric paths of the present invention, respectively.

[0023] A diode D21 is connected in parallel between the source and drain terminals of the n-MOSFET Tr2 in the forward direction from the source terminal to the drain terminal. A bidirectional TVS diode D22 is connected in parallel between the gate and source terminals of the n-MOSFET Tr2.

[0024] The terminal T2 is connected to the electric path Ln4 by the electric path Ln5. The electric path Ln5, one end of which is connected to the terminal T2, is connected to the electric path Ln4 at a connection point P5 via a resistor R3 connected in series. The electric path Ln5 is connected to the electric path Ln6, one end of which is connected to the gate terminal of the p-MOS ET Tr1, at the other end at a connection point P6. The electric path Ln5 is connected to the electric path Ln7, one end of which is connected to the gate terminal of the n-MOS ET Tr2, at the other end at a connection point P7. At this time, the connection points P6 and P7 are disposed between the terminal T2 and the resistor R3. Here, the electric path Ln5 corresponds to the fifth electric path of the present invention, and the resistor R3 corresponds to the resistor of the present invention. The electric paths Ln6 and Ln7 correspond to the sixth and seventh electric paths of the present invention, respectively.

[0025] An n-MOSFET Tr3 is connected between the electric path Ln2 and the electric path Ln4. One end of an electric path Ln8 is connected to the drain terminal of the n-MOSFET Tr3, and the other end of the electric path Ln2 is connected to the electric path Ln2 at a connection point P8. The connection point P8 is disposed on the electric path Ln2 between the source terminal of the p-MOSFET Tr1 and the fuse F. One end of an electric path Ln9 is connected to the source terminal of the n-MOSFET Tr3, and the other end of the electric path Ln9 is connected to the source terminal of the n-MOSFET Tr3 at a connection point P9. The gate terminal of the n-MOSFET Tr3 is grounded by the electric path Ln10. Here, the n-MOSFET Tr3 corresponds to the second N-type MOSFET of the present invention. The electric paths Ln8, Ln9, and Ln10 correspond to the eighth electric path, the ninth electric path, and the ground electric path of the present invention, respectively.

[0026] A diode D31 is connected in parallel between the source and drain terminals of the n-MOSFET Tr3 in the forward direction from the source terminal to the drain terminal. A bidirectional TVS diode D32 is connected in parallel between the gate and source terminals of the n-MOSFET Tr3.

[0027] The electric path Ln1 and the electric path Ln3 are connected by an electric path Ln10 to which a capacitor C1 is connected in series. One end of the electric path Ln10 is connected to the electric path Ln1 at a connection point P1 that is disposed between a terminal T1 and a resistor R1. The other end of the electric path Ln10 is connected to the electric path Ln3 at a connection point P2 that is disposed between a terminal T3 and a resistor R2. The electric path Ln3 is grounded between the connection point P2 and the terminal T3.

[0028] The electric path Ln2 and the electric path Ln4 are connected via an electric path Ln11 to which a capacitor C2 is connected in series. One end of the electric path Ln11 is connected to the electric path Ln2 at a connection point P8 that is disposed between the connection point P8 and the fuse F. The other end of the electric path Ln11 is connected to the electric path Ln4 at a connection point P4 that is disposed between the connection point P9 and the ground terminal T5.

[0029] 2 is a circuit diagram showing a part of the configuration including the terminals T21, T22, and T23 of the electronic device 400. The terminal T21 is connected to the charging terminal ChT by the electric circuit Ln21. The electric circuit Ln21 is connected in series with a fuse F41 and an inductor L41 in this order from the terminal T21 side. The terminal T22 is connected to the electric circuit Ln21 through the electric circuit Ln22. The electric circuit Ln22 is connected in series with an inductor L42, an inductor L43, and a resistor R41 in this order from the terminal T22 side. The electric circuit Ln22 is grounded through a bidirectional TVS diode D42 at a connection point P43 between the inductor L43 and the resistor R41. The electric circuit Ln21 is grounded through a bidirectional TVS diode D41 at a connection point P42 between the connection point P41 between the electric circuit Ln22 and the electric circuit Ln21 and the inductor L41. The terminal T23 is grounded by the electric circuit Ln23. An inductor L44 and an inductor L45 are connected in series to the electric path Ln23 in this order from the terminal T23 side.

[0030] First, FIG. 3 shows a state in which a person 500 touches terminals T1 and T2 of the charger 100. As shown in FIG. At this time, the potential of the electric path Ln2 is 5 V, and the gate voltage VGS of the p-MOSFET Tr1 is −5 V, turning on the p-MOSFET Tr1. This causes a current to flow through resistor R3 of charger 100 via person 500. However, by setting the resistance value of resistor R3 to 100 kΩ, for example, the current flowing through person 500 becomes 5 V / 100 kΩ=50 μA, and the leakage current can be suppressed to less than 100 μA, which is the standard for medical devices, so that no leakage current dangerous to the human body flows.

[0031] 4 shows a state in which a person 500 touches terminals T1 and T3 of the charger 100. At this time, no voltage drop occurs in the p-MOSFET Tr1 that would cause the gate voltage VGS to exceed the threshold value, so the p-MOSFET Tr1 is in the off state and no current flows through the person 500.

[0032] 5 shows a state in which a person 500 touches terminals T2 and T3 of charger 100. At this time, no voltage is applied to person 500 and no current flows through person 500.

[0033] FIG. 6 shows a state where terminals T1, T2, and T3 of the charger 100 are touched. For example, this state is assumed to occur when these three terminals come into contact with a part of the surface of the person 500 that is wet with liquid, or when the three terminals of the charger 100 are accidentally immersed in water in a washroom or the like. At this time, the gate voltage VGS of the p-MOSFETTr1 becomes -5V, so that the p-MOSFETTr1 turns on. Then, a current flows through the resistor R3. Due to the voltage drop occurring in this resistor R3, the gate voltage VGS of the n-MOSFETTr3 exceeds the threshold, and the n-MOSFETTr3 turns on. As a result, when a current flows through the electric path Ln2 via the n-MOSFETTr3, the fuse F opens, and the operation of the charger 100 stops. Therefore, the current does not continue to flow through the person 500. However, in order to realize such an operation, the n-MOSFETTr3 must have a lower threshold value than the n-MOSFETTr2, and a component with a faster switching speed must be selected.

[0034] As described above, according to the first embodiment, the protection circuit 200 having a simple configuration including passive components and transistors can ensure safety against leakage current to the human body.

[0035] <Modification> 7 shows a circuit diagram including a protection circuit 201 of a charger 101 according to a modified example. Configurations common to the protection circuit 200 according to the first embodiment are denoted by common reference numerals and detailed descriptions thereof will be omitted. In the protection circuit 201, one end of the electric path Ln5, the other end of which is connected to the terminal T2, is connected not to the electric path Ln4 but to the electric path Ln2 that connects the source terminal of the p-MOS ET Tr1 to the positive terminal T4, between the source terminal of the p-MOS ET Tr1 and the connection point P8. Here, the electric path Ln5 corresponds to the fifth electric path of the present invention. In the protection circuit 201 configured as above, the p-MOSFET Tr1, the n-MOSFET Tr2, and the n-MOSFET Tr3 are turned on and off in the same manner as in the protection circuit 200 according to the first embodiment, and therefore the same effects can be obtained. Therefore, according to this modification, the protection circuit 201 having a simple configuration made up of passive components and transistors can ensure safety against leakage current to the human body.

[0036] FIG. 8 shows an example of the arrangement of terminals Er1, T2, and T3 in the connector section 110 of the charger 100. The charger 100 includes a flat, approximately rectangular parallelepiped housing 120 and a cable 130. One end of the cable 130 is connected to the housing 120, and the other end is connected to a power source such as an AC adapter. In the planar connector section 110 formed on one surface of the housing 120, terminals T2, T1, and T3 are arranged, in that order from the cable 130 side, along an axis Ax1 in the longitudinal direction of the connector section 110. The terminals T1, T2, and T3 are arranged along the longitudinal direction of the connector section 110. The terminals T21, T22, and T23 of the electronic device 400 are arranged asymmetrically with respect to the axis Ax1 in the arrangement direction. That is, T1 is arranged on one side of the axis Ax, and the terminals T2 and T3 are arranged on the other side of the axis Ax. Since the terminals T21, T22, and T23 of the electronic device 400 are also arranged asymmetrically with respect to the axis in the arrangement direction in order to contact the terminals T1, T2, and T3 on the charger 100 side, even if an attempt is made to connect the electronic device 400 and the connector unit 110 of the charger 100 in the opposite direction to the arrangement direction of the respective terminals, a proper connection cannot be made, and therefore it is possible to prevent the electronic device 400 and the charger 100 from being connected in the wrong direction.

[0037] <Charger configuration> The following describes the arrangement of the terminals T1, T2, and T3 in the charger 100 equipped with the above-mentioned protection circuit 200. The following configuration can also be adopted for the charger 101 equipped with the protection circuit 201, so a separate description will be omitted.

[0038] FIG. 9 shows another example of the arrangement of the terminals T1, T2, and T3 in the connector section 110 of the charger 100. The charger 100 includes a flat, approximately rectangular parallelepiped housing 120 and a cable 130, as in FIG. 9. One end of the cable 130 is connected to the housing 120, and the other end is connected to a power source such as an AC adapter. In the planar connector section 110 formed on one surface of the housing 120, the terminals T2, T1, and T3 are arranged along the axis Ax1 in the longitudinal direction of the connector section 110, in that order from the cable 130 side. The terminal T1, the terminals T2, and the terminals T3 are arranged symmetrically with respect to the axis Ax1 in the longitudinal direction of the connector section 110. In this case, the terminal T1 is set as a positive electrode, and the terminals T2 and T3 are all set as negative electrodes, so that the terminal T1, which is a positive electrode, and the terminals T2 and T3, which are negative electrodes, are arranged symmetrically with respect to the axis Ax2 perpendicular to the longitudinal direction. Therefore, the terminals T21, T22, and T23 of the electronic device 400 are also arranged symmetrically with respect to the axis Ax1 in the arrangement direction in order to contact the terminals T1, T2, and T3 on the charger 100 side, and the terminals T22 and T23 are arranged symmetrically with respect to the axis Ax2 perpendicular to the arrangement direction with respect to the terminal T21. With this arrangement, the electronic device 400 and the connector section 110 of the charger 100 can be properly connected even if they are connected in the opposite direction to the arrangement direction of the respective terminals, so that the electronic device 400 and the charger 100 can be connected without worrying about the orientation, and there is no risk of being unable to connect properly due to a wrong orientation. [Explanation of symbols]

[0039] 100,101...Charger 110 Connector part 200,201...protection circuit 300···Output section 400...Electronic equipment T1, T2, T3... terminals

Claims

1. a contact positive terminal, a first contact negative terminal, and a second contact negative terminal exposed to the outside at a connector portion connected to a device including the secondary battery; a positive terminal and a ground terminal provided in a power output unit that outputs power supplied to the secondary battery via the contact positive terminal, the first contact negative terminal, and the second contact negative terminal; A protection circuit for connecting A P-type MOSFET connected between the contact positive terminal and the positive terminal; a first electric path connecting the contact positive terminal and a drain terminal of the P-type MOSFET; a second current path connecting the positive terminal and a source terminal of the P-type MOSFET; a first N-type MOSFET connected between the second contact negative terminal and the ground terminal; a third electric path that connects the second contact negative terminal and a drain terminal of the first N-type MOSFET and is grounded; a fourth electric path connecting the ground terminal and a source terminal of the first N-type MOSFET; a fifth electric path that connects the first contact negative terminal and the fourth electric path or the second electric path via a resistor; a sixth electric path connecting the gate terminal of the P-type MOSFET and the fifth electric path between the first contact negative terminal and the resistor; a seventh electric path connecting a gate terminal of the first N-type MOSFET and the fifth electric path between the sixth electric path and the resistor; A protection circuit comprising:

2. a second N-type MOSFET connected between the second electric path and the fourth electric path; an eighth electric path connecting a drain terminal of the second N-type MOSFET and the second electric path; a ninth electric path connecting a source terminal of the second N-type MOSFET and the fourth electric path; a grounding path that grounds a gate terminal of the second N-type MOSFET; 2. The protection circuit according to claim 1, further comprising:

3. A charging device including the protection circuit according to claim 1 or 2, A charging device, characterized in that the contact positive terminal, the first contact negative terminal, and the second contact negative terminal are arranged asymmetrically in the connector portion.

4. A charging device including the protection circuit according to claim 1 or 2, A charging device, characterized in that in the connector portion, the first contact negative terminal and the second contact negative terminal are disposed symmetrically with respect to the contact positive terminal.

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