Switch circuit
Patent Information
- Authority / Receiving Office
- JP · JP
- Patent Type
- Patents
- Current Assignee / Owner
- TOYOTA BOSHOKU KK
- Filing Date
- 2023-01-10
- Publication Date
- 2026-08-04
Smart Images
Figure 0007899722000001 
Figure 0007899722000002 
Figure 0007899722000003
Abstract
Description
Technical Field
[0001] The present disclosure relates to a switch circuit.
Background Art
[0002] In a switch circuit that supplies current to a load such as a motor, a minute current flowing through a switching element removes an insulating film that has been protecting the switching element (see Patent Document 1).
Prior Art Documents
Patent Documents
[0003]
Patent Document 1
Summary of the Invention
Problems to be Solved by the Invention
[0004] In a conventional switch circuit, when a large current flows through a switching element, the circuit loss increases. Therefore, when supplying current to a load via a switching element, a limitation may occur in the magnitude of the current.
[0005] One aspect of the present disclosure aims to provide a switch circuit capable of flowing a large current through a switching element.
Means for Solving the Problems
[0006] One aspect of the present disclosure is a switch circuit (1) comprising a load (11), a first switch element (21), a control circuit (31), a supply line (41) that supplies current from a power supply (100) to the load (11), a first switch line (42) that connects the first switch element (21) in parallel with a parallel section (41A) which is part of the supply line (41), a first input line (43) that inputs current from the first switch line (42) to the control circuit (31), a first FET (51) and a second FET (52) provided in the parallel section (41A), and a third FET (53) provided in the first switch line (42) in parallel with the first input line (43).
[0007] The first FET (51) has a first body diode (51A) whose forward direction is the direction in which current is supplied to the load (11). The second FET (52) has a second body diode (52A) whose forward direction is the opposite to the forward direction of the first body diode (51A). The third FET (53) has a third body diode (53A) whose forward direction is the direction in which current is supplied to the load (11) via the first switch element (21).
[0008] The control circuit (31) is configured to turn on the first FET (51) and the second FET (52) and turn off the third FET (53) when there is no current input from the first input line (43), and to turn off the first FET (51) and the second FET (52) and turn on the third FET (53) when there is current input from the first input line (43).
[0009] With this configuration, when the first switch element (21) is closed, the first FET (51) and the second FET (52) turn off, so no current flows in the parallel section (41A), and current is supplied to the load (11) from the first switch line (42) to which the first switch element (21) is provided. As a result, the current from the power supply (100) is cut off in the parallel section (41A), so a large current can flow through the first switch element (21). In addition, current leakage from the parallel section (41A) to the first input line (43) is suppressed, so the control circuit (31) can detect the opening and closing of the first switch element (21).
[0010] Furthermore, when the first switch element (21) is open, the third FET (53) turns off, so no current flows through the first switch line (42), and current is supplied to the load (11) from the parallel section (41A). This suppresses current leakage from the parallel section (41A) to the first input line (43), allowing the control circuit (31) to detect the opening and closing of the first switch element (21).
[0011] One aspect of the present disclosure may further include a second switch element (22), a second switch line (44) connecting the second switch element (22) in parallel with the parallel section (41A), a second input line (45) inputting current from the second switch line (44) to the control circuit (31), and a fourth FET (54) provided in parallel with the second input line (45) on the second switch line (44). The fourth FET (54) may have a fourth body diode (54A) whose forward direction is the direction in which current is supplied to the load (11) via the second switch element (22).
[0012] The control circuit (31) may be configured to turn on the first FET (51) and the second FET (52) and turn off the third FET (53) and the fourth FET (54) when there is no current input from both the first input line (43) and the second input line (45), and to turn off the first FET (51), the second FET (52), and the third FET (53) and turn on the fourth FET (54) when there is current input from the second input line (45).
[0013] With this configuration, a large current can be passed through both the first switch element (21) and the second switch element (22). In addition, the control circuit (31) can detect the opening and closing of both the first switch element (21) and the second switch element (22).
[0014] One aspect of the present disclosure may further include a current switching circuit (61) provided between the connection point of a first switch line (42) and a second switch line (44) in the supply line (41) and the load (11). The second switch element (22) may be configured not to close simultaneously with the first switch element (21). The control circuit (31) may be configured to control the current switching circuit (61) so that current flows to the load (11) in a first direction when there is a current input from the first input line (43), and to control the current switching circuit (61) so that current flows to the load (11) in a second direction opposite to the first direction when there is a current input from the second input line (45).
[0015] With this configuration, the direction of the current supplied to the load (11) can be changed by selecting the first switch element (21) and the second switch element (22).
[0016] One aspect of this disclosure may be arranged in a vehicle seat (200). With this configuration, it is possible to supply the current necessary to the load (11) that deforms the vehicle seat (200) while removing the insulating film of the first switch element (21).
[0017] Note that the reference signs in each of the above parentheses are an example showing the correspondence with the specific configuration and the like described in the embodiments to be described later, and the present disclosure is not limited to the specific configuration and the like indicated by the reference signs in the above parentheses.
Brief Description of Drawings
[0018] [Figure 1] FIG. 1 is a schematic circuit diagram of a switch circuit in an embodiment. [Figure 2] FIG. 2 is a schematic perspective view showing a vehicle seat in an embodiment. [Figure 3] FIG. 3 is a schematic circuit diagram showing a state in which a first switch element is closed in the switch circuit of FIG. 1. [Figure 4] FIG. 4 is a schematic circuit diagram showing a state immediately after a first switch element is opened in the switch circuit of FIG. 1. [Figure 5] FIG. 5 is a schematic circuit diagram showing a state in which a second switch element is closed in the switch circuit of FIG. 1.
Embodiments for Carrying Out the Invention
[0019] Hereinafter, embodiments to which the present disclosure is applied will be described with reference to the drawings. [1. First Embodiment] [1-1. Configuration] The switch circuit 1 shown in FIG. 1 includes a load 11, a first switch element 21, a second switch element 22, a control circuit 31, a supply line 41, a first switch line 42, a first input line 43, a second switch line 44, a second input line 45, a first FET 51, a second FET 52, a third FET 53, a fourth FET 54, and a current switching circuit 61.
[0020] The switch circuit 1 is disposed on a vehicle seat 200 shown in FIG. 2. The vehicle seat 200 is installed in a vehicle such as an automobile, a railway vehicle, a ship, or an aircraft. The switch circuit 1 is used, for example, for driving a slide device 201 or a reclining device 202 of the vehicle seat 200.
[0021] <Load> The load 11 shown in FIG. 1 is, for example, a motor that displaces the slide device 201 or the reclining device 202. A current is supplied from the power source 100 included in the vehicle on which the vehicle seat 200 is installed to the load 11.
[0022] <First switch element> The first switch element 21 is configured to allow a current to flow in the first direction to the load 11 in the closed state.
[0023] The contacts of the first switch element 21 are connected to the power source 100 in the closed state and grounded in the open state. The first switch element 21 opens and closes in conjunction with, for example, a physical switch for sliding the vehicle seat 200 forward.
[0024] <Second switch element> The second switch element 22 is configured to allow a current to flow in the second direction opposite to the first direction to the load 11 in the closed state.
[0025] The contacts of the second switch element 22 are connected to the power source 100 in the closed state and grounded in the open state. The second switch element 22 opens and closes in conjunction with, for example, a physical switch for sliding the vehicle seat 200 backward.
[0026] The second switch element 22 is configured not to close simultaneously with the first switch element 21 by a physical structure (for example, a lock mechanism). Therefore, the second switch element 22 can be closed only when the first switch element 21 is open.
[0027] <Control circuit> The control circuit 31 is an interface circuit configured to receive an input of a signal current and switch on and off each of a plurality of FETs (field effect transistors) included in the switch circuit 1. The control circuit 31 is connected to the gates of each FET.
[0028] The control circuit 31 is connected to a first input line 43, a second input line 45, and multiple output lines connected to the gates of each FET. For example, a known microcomputer can be used as the control circuit 31. The specific control of the control circuit 31 will be described later.
[0029] <Supply Line> The supply line 41 supplies current from the power supply 100 to the load 11. Specifically, the supply line 41 connects the power supply 100 and the load 11 via a current switching circuit 61.
[0030] Furthermore, the supply line 41 has a parallel section 41A in which the first switch line 42 and the second switch line 44 are connected in parallel. The parallel section 41A is located closer to the power supply 100 (i.e., upstream) than the current switching circuit 61.
[0031] <First switch line> The first switch line 42 connects the first switch element 21 in parallel with the parallel section 41A of the supply line 41. The first switch line 42 is provided with the first switch element 21 and the third FET 53 in order from the side closest to the power supply 100.
[0032] <First Input Line> The first input line 43 supplies current to the control circuit 31 from the first switch line 42. One end of the first input line 43 is connected between the first switch element 21 and the third FET 53 in the first switch line 42. When the first switch element 21 closes, current is supplied from the first input line 43 to the control circuit 31.
[0033] <Second switch line> The second switch line 44 connects the second switch element 22 in parallel with the parallel section 41A of the supply line 41. The second switch line 44 is provided with the second switch element 22 and the fourth FET 54 in order from the side closest to the power supply 100.
[0034] <Second input line> The second input line 45 supplies current to the control circuit 31 from the second switch line 44. One end of the second input line 45 is connected between the second switch element 22 and the fourth FET 54 in the second switch line 44. When the second switch element 22 closes, current is supplied to the control circuit 31 from the second input line 45.
[0035] <fet> The first FET 51 and the second FET 52 are general-purpose field-effect transistors provided in the parallel section 41A of the supply line 41. The first FET 51 and the second FET 52 are connected in parallel with the first switch element 21 and the second switch element 22, respectively.
[0036] The first FET 51 is switched on and off by the current input from the control circuit 31. The first FET 51 has a first body diode 51A whose forward direction is the direction in which current is supplied from the power supply 100 to the load 11. The body diode is a diode located at the back gate.
[0037] The second FET 52, along with the first FET 51, is switched on and off by the current input from the control circuit 31. The second FET 52 has a second body diode 52A whose forward direction is the opposite of the forward direction of the first body diode 51A (i.e., the reverse current direction toward the power supply 100).
[0038] The first FET 51 and the second FET 52 are simultaneously switched on or off by the control circuit 31. In other words, the control circuit 31 switches between a state where both the first FET 51 and the second FET 52 are off and a state where both the first FET 51 and the second FET 52 are on.
[0039] When both the first FET 51 and the second FET 52 are off, current flows through the first FET 51 toward the load 11, but no current flows in the reverse direction toward the power supply 100. On the other hand, no current flows through the second FET 52 toward the load 11. As a result, no current flows through the parallel section 41A.
[0040] When both the first FET 51 and the second FET 52 are turned on, current flows towards the load 11 in both the first FET 51 and the second FET 52. As a result, current flows through the parallel section 41A.
[0041] The third FET 53 is a general-purpose field-effect transistor provided in parallel with the first input line 43 in the first switch line 42. Specifically, the third FET 53 is provided in the first switch line 42 on the side closer to the load 11 than the connection point P2 between the first switch element 21 and the first input line 43.
[0042] The third FET 53 has a third body diode 53A whose forward direction is the direction in which current is supplied to the load 11 via the first switch element 21. The third FET 53 is switched on or off by the control circuit 31. When the third FET 53 is off, no reverse current flows in the first switch line 42 from the first switch element 21 to the power supply 100.
[0043] The fourth FET 54 is a general-purpose field-effect transistor provided in parallel with the second input line 45 in the second switch line 44. Specifically, the fourth FET 54 is provided in the second switch line 44 on the side closer to the load 11 than the connection point P3 between the second switch element 22 and the second input line 45.
[0044] The fourth FET 54 has a fourth body diode 54A whose forward direction is the direction in which current is supplied to the load 11 via the second switch element 22. The fourth FET 54 is switched on or off by the control circuit 31. When the fourth FET 54 is off, no reverse current flows in the second switch line 44 from the second switch element 22 to the power supply 100.
[0045] <Current switching circuit> The current switching circuit 61 is provided in the supply line 41 between the connection point P1 of the first switch line 42 and the second switch line 44 and the load 11.
[0046] The current switching circuit 61 includes a first line 61A, a second line 61B, a third line 61C, a fourth line 61D, a fifth line 61E, a first switching FET 61F, a second switching FET 61G, a third switching FET 61H, and a fourth switching FET 61I.
[0047] The first line 61A supplies current in the first direction to the second line 61B, which is connected to the load 11, when the first switching element 21 is closed. The first line 61A is provided with a first switching FET 61F.
[0048] The third line 61C is connected in series with the second line 61B and the fourth line 61D, and also connects the second line 61B to ground. The third line 61C is provided with a second switching FET 61G.
[0049] The fourth line 61D supplies current in the second direction to the second line 61B, which is connected to the load 11, when the second switching element 22 is closed. The fourth line 61D is connected in parallel with the first line 61A. The fourth line 61D is also provided with a third switching FET 61H.
[0050] The fifth line 61E is connected in series with the first line 61A and the second line 61B, and also connects the second line 61B to ground. The fifth line 61E is connected in parallel with the third line 61C. In addition, the fifth line 61E is provided with a fourth switching FET 61I.
[0051] When the second switching element 22 is open, the control circuit 31 turns on the first switching FET 61F and the second switching FET 61G, while turning off the third switching FET 61H and the fourth switching FET 61I. As a result, current flows in the order of the first line 61A, the second line 61B, and the third line 61C.
[0052] When the second switching element 22 is closed, the control circuit 31 turns off the first switching FET 61F and the second switching FET 61G, while turning on the third switching FET 61H and the fourth switching FET 61I. As a result, current flows in the order of the fourth line 61D, the second line 61B, and the fifth line 61E.
[0053] <Control by a control circuit> As shown in Figure 1, when both the first switch element 21 and the second switch element 22 are open, that is, when there is no current input from both the first input line 43 and the second input line 45, the control circuit 31 turns on the first FET 51 and the second FET 52, and turns off the third FET 53 and the fourth FET 54.
[0054] In this state, the current supplied from the power supply 100 flows to the load 11 through the parallel section 41A where the first FET 51 and the second FET 52 are provided. At this time, the third FET 53 and the fourth FET 54 prevent current from flowing back from the supply line 41 to the first switch line 42 and the second switch line 44 (see dashed lines in Figure 1). This prevents short circuits in the circuit and, consequently, damage to the components.
[0055] As shown in Figure 3, when the first switch element 21 is closed, that is, when there is current input from the first input line 43, the control circuit 31 turns off the first FET 51 and the second FET 52, turns on the third FET 53, and turns off the fourth FET 54. Also, when there is current input from the first input line 43, the control circuit 31 controls the current switching circuit 61 so that current flows to the load 11 in the first direction.
[0056] In this state, the current supplied from the power supply 100 flows to the load 11 through the first switch line 42, which is equipped with the first switch element 21. At this time, the fourth FET 54 prevents current from flowing back from the first switch line 42 to the second switch line 44 (see the dashed line in Figure 3). In addition, the first FET 51 prevents reverse current flow in the parallel section 41A.
[0057] When opening the first switch element 21 from its closed state, if the second FET 52 is not present, current will flow back from the parallel section 41A to the first switch element 21 until the third FET 53 switches off, as shown by the dashed line in Figure 4.
[0058] In contrast, by providing the second FET 52 in the parallel section 41A, the third FET 53 is turned off, and no current flows through the parallel section 41A until the first FET 51 and the second FET 52 are turned on. In other words, the second FET 52 suppresses the occurrence of a short circuit in the circuit when the first switch element 21 is opened.
[0059] As shown in Figure 5, when the second switch element 22 is closed, that is, when there is current input from the second input line 45, the control circuit 31 turns off the first FET 51 and the second FET 52, turns on the fourth FET 54, and turns off the third FET 53. Also, when there is current input from the second input line 45, the control circuit 31 controls the current switching circuit 61 so that current flows to the load 11 in the second direction.
[0060] In this state, the current supplied from the power supply 100 flows to the load 11 through the second switch line 44, which is equipped with the second switch element 22. At this time, the third FET 53 prevents current from flowing back from the second switch line 44 to the first switch line 42 (see dashed line in Figure 5).
[0061] When opening the closed second switch element 22, the current flow into the parallel section 41A is suppressed by the off second FET 52, just as when opening the first switch element 21.
[0062] [1-2. Effects] According to the embodiments described in detail above, the following effects can be obtained. (1a) When the first switch element 21 is closed, the first FET 51 and the second FET 52 are turned off, so no current flows through the parallel section 41A, and current is supplied to the load 11 from the first switch line 42 on which the first switch element 21 is located. As a result, the current from the power supply 100 is cut off in the parallel section 41A, so a large current can flow through the first switch element 21. In addition, current leakage from the parallel section 41A to the first input line 43 is suppressed, so the control circuit 31 can detect the opening and closing of the first switch element 21.
[0063] (1b) When the first switch element 21 is open, the third FET 53 is turned off, so no current flows through the first switch line 42, and current is supplied to the load 11 from the parallel section 41A. As a result, current leakage from the parallel section 41A to the first input line 43 is suppressed, so that the control circuit 31 can detect the opening and closing of the first switch element 21.
[0064] (1c) By providing FETs in the first switch line 42 and the second switch line 44, a large current can be passed through the first switch element 21 and the second switch element 22, respectively. In addition, the control circuit 31 can detect the opening and closing of the first switch element 21 and the second switch element 22, respectively.
[0065] (1d) The direction of the current supplied to the load 11 can be changed by selecting between the first switch element 21 and the second switch element 22. (1e) The insulating film of the first switch element 21 and the second switch element 22 can be removed while supplying the current necessary to the load 11 that deforms the vehicle seat 200.
[0066] [2. Other Embodiments] While embodiments of this disclosure have been described above, it goes without saying that this disclosure is not limited to the embodiments described above and can take various forms.
[0067] (2a) The switch circuit of the above embodiment does not necessarily have to include a second switch element. In other words, the switch circuit may have only one switch element. (2b) The switch circuit of the above embodiment can also be used for articles other than sheets.
[0068] (2c) The functions of one component in the above embodiment may be distributed among multiple components, or the functions of multiple components may be integrated into one component. Also, some parts of the configuration of the above embodiment may be omitted. Also, at least some parts of the configuration of the above embodiment may be added to, substituted for, or otherwise replaced with the configuration of other above embodiments. Any aspect of the technical concept specified by the wording of the claims is an embodiment of the present disclosure. [Explanation of symbols]
[0069] 1...Switch circuit, 11...Load, 21...First switching element, 22...Second switching element, 31...Control circuit, 41...Supply line, 41A...Parallel section, 42...First switch line, 43...First input line, 44...Second switch line, 45...Second input line, 51...First FET, 51A...First body diode, 52...Second FET, 52A...Second body diode, 53...Third FET, 53A...Third body diode, 54...Fourth FET, 54A...4th body diode, 61...current switching circuit, 61A...1st line, 61B...2nd line, 61C...3rd line, 61D...4th line, 61E...5th line, 61F...1st switching FET, 61G...2nd switching FET, 61H...Third switching FET, 61I...Fourth switching FET, 100...Power supply.< / fet>
Claims
1. Load and First switching element and Control circuit and A supply line that supplies current from the power source to the load, A first switch line that connects the first switch element in parallel with a parallel section which is part of the supply line, A first input line that branches off from a position on the load side of the first switch element in the first switch line and inputs current to the control circuit, The first FET and the second FET are provided in series connection in the parallel section, A third FET is provided in the first switch line on the load side of the branching point to the first input line, Equipped with, The first switch element is configured to be able to switch between a closed state in which the load-side contact is connected to the power supply and an open state in which the load-side contact is connected to ground. The first FET has a first body diode whose forward direction is the direction in which current is supplied to the load. The second FET has a second body diode whose forward direction is opposite to that of the first body diode. The third FET has a third body diode whose forward direction is the direction in which current is supplied to the load via the first switching element. The aforementioned control circuit is When there is no current input from the first input line, the first FET and the second FET are turned on, and the third FET is turned off. A switch circuit configured to turn off the first FET and the second FET, and turn on the third FET, when there is a current input from the first input line.
2. A switch circuit according to claim 1, The second switching element, A second switch line connects the second switch element in parallel with the parallel section, A second input line that branches off from a position on the load side of the second switch element in the second switch line and inputs current to the control circuit, A fourth FET is provided in the second switch line on the load side of the branching point to the second input line, Furthermore, The second switch element is configured to be able to switch between a closed state in which the load-side contact is connected to the power supply and an open state in which the load-side contact is connected to ground. The fourth FET has a fourth body diode whose forward direction is the direction in which current is supplied to the load via the second switching element. The aforementioned control circuit is When there is no current input from both the first input line and the second input line, the first FET and the second FET are turned on, and the third FET and the fourth FET are turned off. A switch circuit configured to turn off the first FET, the second FET, and the third FET, and turn on the fourth FET, when there is a current input from the second input line.
3. A switch circuit according to claim 2, The supply line further includes a current switching circuit provided between the connection point of the first switch line and the second switch line and the load, The second switch element is configured not to close simultaneously with the first switch element. The aforementioned control circuit is When there is a current input from the first input line, the current switching circuit is controlled so that current flows in the first direction to the load. A switch circuit configured to control the current switching circuit so that, when there is a current input from the second input line, current flows to the load in a second direction opposite to the first direction.
4. A switch circuit according to any one of claims 1 to 3, A switch circuit located in a vehicle seat.