Power supply control device

Abstract

A power feed control device (10) comprises an element unit (52), a voltage conversion unit (30), and a control unit (16). The voltage conversion unit (30) performs: a first conversion operation for stepping up or stepping down a voltage applied to a first conductive path (41) and applying the output voltage to a third conductive path (43); and a second conversion operation for stepping up or stepping down the voltage applied to the third conductive path (43) and applying the output voltage to the first conductive path (41). The element unit (52) is allowed to flow current therethrough to the power path (80) side and is enabled to block the current flowing therethrough to the electricity storage unit (92) side. The control unit (16) causes the voltage conversion unit (30) to stop or causes the voltage conversion unit (30) to perform the second conversion operation when the supply of power from a power supply unit (91) to the power path (80) is not in a failure state but in a normal state, and causes the voltage conversion unit (30) to start the first conversion operation when the supply of power from the power supply unit (91) to the power path (80) is brought into the failure state.

Description

Technical Field

[0001] The present disclosure relates to a power supply control device.

Background Art

[0002] Patent Document 1 discloses a power supply system. The power supply system of Patent Document 1 includes a main battery and a sub-battery, and operates to switch the power supply source to a load from the main battery side to the sub-battery side when power supply from the main battery side is interrupted. In the power supply system of Patent Document 1, a body diode is provided in a switch between the sub-battery and the load, and when power from the main battery is interrupted, power is supplied to the load via the body diode even when the switch is in an off state, so that the power supply is not interrupted.

Prior Art Documents

Patent Documents

[0003]

Patent Document 1

Summary of Invention

Problems to be Solved by the Invention

[0004] The power supply system of Patent Document 1 has a concern that an appropriate voltage cannot be supplied to the load when the output voltage of the sub-battery decreases.

[0005] The present disclosure provides a technology that, in a power supply control device capable of a backup operation of supplying power based on a power storage unit different from a power supply unit, facilitates supplying power more quickly during the backup operation, and facilitates outputting an appropriate voltage even when the output voltage of the power storage unit changes.

Means for Solving the Problems

[0006] A power supply control device that is one aspect of the present disclosure is A power supply control device is included in an in-vehicle system comprising a power supply unit that supplies power, a power path which is a path through which power based on the power supply unit is transmitted, and a power storage unit different from the power supply unit, and controls the power supply from the power storage unit, A first conductive path to which a voltage based on the output of the energy storage unit is applied, An element portion having one end electrically connected to the first conductive path, A second conductive path is electrically connected to the other end of the element portion and forms a current-carrying path between the element portion and the power line, A voltage conversion unit connected in parallel to the element unit between the energy storage unit and the power line, Between the voltage conversion unit and the power line, a third conductive path electrically connected to the voltage conversion unit, A control unit that controls the voltage conversion unit, Equipped with, The voltage conversion unit performs a first conversion operation to increase or decrease the voltage applied to the first conductive path and apply the output voltage to the third conductive path, and a second conversion operation to increase or decrease the voltage applied to the third conductive path and apply the output voltage to the first conductive path. The element portion is designed to allow current to flow through it to the power line side, and to be capable of blocking current from flowing through it to the energy storage portion side. The control unit either stops the voltage conversion unit or causes the voltage conversion unit to perform the second conversion operation when the power supply from the power supply unit to the power line is in a normal state and not in a state of power failure, and causes the voltage conversion unit to start the first conversion operation when the power failure occurs. [Effects of the Invention]

[0007] The technology disclosed herein facilitates faster power supply during backup operation and makes it easier to output an appropriate voltage even when the output voltage of the energy storage unit changes. [Brief explanation of the drawing]

[0008] [Figure 1]Figure 1 is a schematic circuit diagram showing an example of an in-vehicle system including a power supply control device according to the first embodiment. [Figure 2] Figure 2 is a schematic circuit diagram showing an example of a voltage conversion section. [Figure 3] Figure 3 is a flowchart illustrating the backup control flow performed in the power supply control device of the first embodiment. [Figure 4] Figure 4 is a schematic circuit diagram showing an example of an in-vehicle system including a power supply control device according to the second embodiment. [Figure 5] Figure 5 is a schematic circuit diagram showing an example of an in-vehicle system including a power supply control device according to the third embodiment. [Figure 6] Figure 6 is a schematic circuit diagram showing an example of an in-vehicle system including a power supply control device according to the fourth embodiment. [Figure 7] Figure 7 is a schematic circuit diagram showing an example of an in-vehicle system including a power supply control device according to the fifth embodiment. [Figure 8] Figure 8 is a schematic circuit diagram showing an example of an in-vehicle system including a power supply control device according to the sixth embodiment. [Modes for carrying out the invention]

[0009] [Description of Embodiments in this Disclosure] Embodiments relating to this disclosure are listed and illustrated below. The features [1] to

[11] illustrated below may be combined in any non-contradictory way.

[0010] [1] A power supply control device included in an in-vehicle system comprising a power supply unit that supplies power, a power line which is a path through which power based on the power supply unit is transmitted, and a power storage unit different from the power supply unit, which controls the power supply from the power storage unit, A first conductive path to which a voltage based on the output of the energy storage unit is applied, An element portion having one end electrically connected to the first conductive path, A second conductive path is electrically connected to the other end of the element portion and forms a current-carrying path between the element portion and the power line, a voltage conversion unit connected in parallel to the element unit between the power storage unit and the power path, a third conductive path electrically connected to the voltage conversion unit between the voltage conversion unit and the power path, a control unit configured to control the voltage conversion unit, comprising, the voltage conversion unit performs a first conversion operation of stepping up or stepping down a voltage applied to the first conductive path to apply an output voltage to the third conductive path, and a second conversion operation of stepping up or stepping down a voltage applied to the third conductive path to apply an output voltage to the first conductive path, the element unit is configured to allow current to flow to the power path side through itself, and to block current from flowing to the power storage unit side through itself, the control unit keeps the voltage conversion unit stopped or causes the voltage conversion unit to perform the second conversion operation in a normal state where power supply from the power supply unit to the power path is not in a failure state, and causes the voltage conversion unit to start the first conversion operation when the failure state occurs power supply control device.

[0011] The power supply control device according to the above [1] can utilize the path via the element unit and the path via the voltage conversion unit when performing a backup operation of supplying power based on the power storage unit. For example, this power supply control device is capable of responding to rapidly supply power using the path via the element unit at a time when sufficient power supply is not achieved by the path via the voltage conversion unit. On the other hand, when the output voltage of the power storage unit decreases, it is possible to perform a boosting operation by the voltage conversion unit and perform a backup operation so as to apply a desired output voltage to the third conductive path.

[0012] [2] The control unit causes the voltage conversion unit to start the first conversion operation so as to apply an output voltage of a first value to the third conductive path when the failure state occurs, when the voltage of the second conductive path is equal to or less than a second value in the failure state, a current flows from the power storage unit side to the power path side via the element unit, At least after the aforementioned failure state occurs, the flow of current from the second conductive path side to the energy storage side in the element portion is interrupted. The power supply control device described in [1].

[0013] The power supply control device described in [2] above is configured such that when the voltage of the second conductive path is less than or equal to the second value in the failure state, current flows from the energy storage unit to the power path through the element unit. In other words, when the output of the voltage conversion unit has not risen to the extent that "the voltage of the second conductive path exceeds the second value", power based on the energy storage unit can be supplied to the power path through the element unit, so that current can be supplemented by the path through the element unit when the output of the voltage conversion unit is low. Furthermore, at least after the failure state occurs, the element unit can block the flow of current from the second conductive path to the energy storage unit, so that as long as this blocking function is active, it is possible to prevent current based on the output of the voltage conversion unit from flowing from the second conductive path to the energy storage unit.

[0014] [3] When the failure state occurs, the control unit causes the voltage conversion unit to start the first conversion operation of applying the output voltage of the first value to the third conductive path, and then causes the voltage conversion unit to perform the first conversion operation of applying the output voltage of a third value smaller than the first value to the third conductive path. The power supply control device described in [2].

[0015] The power supply control device described in [3] above can, when the failure occurs, start voltage conversion to apply an output voltage of a first value to the third conductive path, and then switch the voltage conversion to apply an output voltage of a third value lower than the first value. Therefore, after a certain amount of time has elapsed, this power supply control device can suppress the voltage output by the voltage conversion unit and reduce the output energy.

[0016] [4] The configuration is such that the second conductive path and the third conductive path are short-circuited, The second value is the value obtained by subtracting the value of the voltage drop occurring in the element from the value of the voltage applied to the first conductive path. The first value is greater than the second value. The third value is less than the first value and greater than the second value. The power supply control device described in [3].

[0017] The power supply control device described in [4] above can, in the event of a power failure, perform voltage conversion to apply an output voltage of a first value greater than the second value described above, thereby bringing the voltage of the third conductive path closer to a relatively high target voltage (first value) as quickly as possible. Furthermore, after a certain amount of time has elapsed since the power failure, this power supply control device can suppress output energy by limiting the voltage output by the voltage conversion unit to a third value, and by making the third value greater than the second value, it can suppress the inflow of current through the element unit.

[0018] [5] The configuration is such that the second conductive path and the third conductive path are short-circuited, The second value is obtained by subtracting the value of the voltage drop that occurs in the element when current flows from the first conductive path to the second conductive path in the element from the value of the voltage applied to the first conductive path. The third value is smaller than the first value and smaller than the second value. The power supply control device described in [3].

[0019] The power supply control device described in [5] above can suppress output energy by reducing the voltage output by the voltage conversion unit to a third value after a certain amount of time has elapsed since the failure, and by making the third value smaller than the second value, the output energy can be further suppressed.

[0020] [6] The element section comprises a diode and an opening / closing section provided in parallel with the diode. A voltage based on the output of the energy storage unit is applied to the anode of the diode. The cathode of the diode is electrically connected to the second conductive path. The aforementioned switching unit allows bidirectional energization when it is in the ON state. The second value is a first subtraction value obtained by subtracting the voltage drop caused by the switching unit and the diode from the voltage applied to the first conductive path when the switching unit is ON, and a second subtraction value obtained by subtracting the voltage drop caused by the diode from the voltage applied to the first conductive path when the switching unit is OFF. The first value is greater than both the first subtraction value and the second subtraction value. The control unit, when the state changes from the normal state to the failure state, turns on the switching unit and causes the voltage conversion unit to start the first conversion operation, which applies the output voltage of the first value to the third conductive path. When a predetermined condition is met while the voltage conversion unit is performing the first conversion operation, the control unit switches the switching unit to the off state, and after switching the switching unit to the off state, causes the voltage conversion unit to perform the first conversion operation, which applies the output voltage of the third value to the third conductive path. The third value is greater than the second subtraction value. The power supply control device described in [4].

[0021] The power supply control device described in [6] above has an element section configured such that a diode and a switch are provided in parallel, with the anode of the diode connected to the first conductive path and the cathode connected to the second conductive path. Therefore, in the element section, even when the switch is in the off state, if the voltage of the second conductive path is lower than the voltage of the first conductive path by a certain value or more, current is continuously permitted to flow from the first conductive path to the second conductive path, and when the switch is in the on state, current is permitted to flow through the switch. Furthermore, this power supply control device turns on the switch when the state changes from the normal state to a failure state, thereby reducing losses in the element section and enabling the supply of more power through the element section at an earlier stage. Furthermore, this power supply control device switches the switch to the off state in accordance with the fulfillment of predetermined conditions during the first conversion operation. Therefore, this power supply control device can prevent current from flowing backward in the element section after the first conversion operation has progressed until the predetermined conditions are met. Furthermore, after switching the switching unit to the off state, this power supply control device causes the voltage conversion unit to perform a first conversion operation, which applies an output voltage of a third value (a value smaller than the first value and larger than the second subtraction value) to the third conductive path. Therefore, after a certain amount of time has elapsed, this power supply control device can continue to supply power by suppressing the forward current in the diode and using the output operation of the voltage conversion unit with suppressed energy.

[0022] [7] The predetermined condition is that the voltage of the second conductive path reaches a predetermined value equal to or greater than the voltage of the first conductive path. The power supply control device described in [6].

[0023] The power supply control device described in [7] above can continue to supply power through the switch after a failure occurs until the voltage of the second conductive path rises, and after it rises, it can reliably prevent reverse current in the element section.

[0024] [8] The predetermined condition is that a predetermined time has elapsed since the first conversion operation was started in the voltage conversion unit after the failure state. The power supply control device described in [6].

[0025] The power supply control device described in [8] above can continue to supply power through the switching unit after a failure has occurred, until a predetermined time has elapsed since the voltage conversion unit started outputting current, and after the predetermined time has elapsed, it can reliably prevent reverse current in the element unit.

[0026] [9] The predetermined condition is that the current flowing through the element reaches a lower limit value or less. The power supply control device described in [6].

[0027] The power supply control device described in [9] above can allow energization through the switching unit after a failure occurs until the current flowing through the element reaches below the lower limit, and can reliably prevent reverse current in the element when the current flowing through the element reaches below the lower limit.

[0028]

[10] The predetermined condition is that the current output by the voltage conversion unit to the third conductive path after the failure state reaches a reference value or higher. The power supply control device described in [6].

[0029] The power supply control device described in

[10] above can allow current to flow through the switching unit after a failure occurs until the current output by the voltage conversion unit to the third conductive path reaches a reference value or higher, and can reliably prevent reverse current in the element unit when the current output by the voltage conversion unit to the third conductive path reaches a reference value or higher.

[0030]

[11] The element section comprises a diode and a reverse current prevention switch, The diode and the reverse current prevention switch are arranged in series with respect to each other between the first conductive path and the second conductive path. The diode blocks the flow of current through it to the first conductive path and allows the flow of current through it to the second conductive path. The reverse current prevention switch, when in the off state, blocks the flow of current through itself to the second conductive path, and when in the on state, allows the flow of current through itself to the second conductive path. The control unit controls the reverse current prevention switch to the OFF state when the normal state is reached, causing the voltage conversion unit to perform the second conversion operation, and when the failure state occurs, it switches the reverse current prevention switch to the ON state and causes the voltage conversion unit to start the first conversion operation. The power supply control device described in [1].

[0031] The power supply control device described in

[11] above can charge the energy storage unit under normal conditions, and can prevent the current supplied from the voltage conversion unit to the first conductive path from flowing back into the second conductive path using a reverse current prevention switch. Furthermore, the power supply control device described in

[11] above can immediately supply power to the second conductive path via the element unit in the event of a failure, and can also apply the voltage adjusted by the voltage conversion unit to the third conductive path. [Details of the embodiments of this disclosure]

[0032] <First Embodiment> 1. Overview of the in-vehicle system Figure 1 shows the in-vehicle system 2. The in-vehicle system 2 in Figure 1 mainly comprises an in-vehicle power supply system 3 and a load 101. The in-vehicle power supply system 3 will also be referred to as power supply system 3 in the following description. The in-vehicle system 2 is a system that supplies power to the load 101 by power supply system 3 and operates the load 101. In Figure 1, load 101 is shown as an example of an in-vehicle load, but the in-vehicle system 2 may be provided with other loads.

[0033] Load 101 is an electrical component mounted on a vehicle. Load 101 operates by receiving power supplied via the power line 80. The type of load 101 is not limited. Various known vehicle components can be used as load 101. Load 101 may have multiple electrical components or may be a single electrical component.

[0034] The power supply system 3 is a system that supplies power to the load 101. The power supply system 3 supplies power to the load 101 using either the power supply unit 91 or the energy storage unit 92 as the power source. The power supply system 3 can supply power to the load 101 from the power supply unit 91, and if the power supply from the power supply unit 91 is interrupted due to a malfunction or other reason, for example, the energy storage unit 92 can supply power to the load 101.

[0035] 2. Overview of the Power System The power supply system 3 includes a power supply unit 91, a power storage unit 92, a power supply control device 10, a power line 80, a diode 71, and the like.

[0036] The power supply unit 91 is an on-board power supply capable of supplying power to the load 101. The power supply unit 91 is configured as a known on-board battery, such as a lead-acid battery. The power supply unit 91 may be configured as a battery other than a lead-acid battery, or it may have a power supply means other than a battery in place of or in addition to a battery. The positive terminal of the power supply unit 91 is electrically connected to the first power line 81, which is part of the power line 80, in a short-circuit configuration. The negative terminal of the power supply unit 91 is electrically connected to the ground 83 in a short-circuit configuration. The power supply unit 91 applies a constant DC voltage to the first power line 81. The voltage applied by the power supply unit 91 to the first power line 81 may vary slightly from the constant value.

[0037] The energy storage unit 92 is a different power source from the power supply unit 91. The energy storage unit 92 is a power source that becomes a power supply source at least when the power supply from the power supply unit 91 is interrupted. The energy storage unit 92 is composed of known energy storage means, such as an electric double-layer capacitor (EDLC). The energy storage unit 92 may be composed of a capacitor other than an electric double-layer capacitor, and may be equipped with other energy storage means (such as a battery) in place of or in addition to the capacitor. The positive electrode of the energy storage unit 92 is electrically connected to the first conductive path 41 in a configuration that is short-circuited to the first conductive path 41. The negative electrode of the energy storage unit 92 is electrically connected to the ground 83 in a configuration that is short-circuited to the ground 83. The output voltage of the energy storage unit 92 (the voltage applied to the first conductive path 41 by the energy storage unit 92) may be greater than or less than the output voltage of the power supply unit 91 (the voltage applied to the first power path 81 by the power supply unit 91).

[0038] In this specification, unless otherwise specified, voltage refers to the voltage relative to ground potential (e.g., 0V), and is the potential difference with respect to ground potential. For example, the voltage applied to the first power line 81 is the potential difference between the potential of the first power line 81 and ground potential. The voltage applied to the first conductive line 41 is the potential difference between the potential of the first conductive line 41 and ground potential.

[0039] The power path 80 is a path through which power from the power supply unit 91 is transmitted, and is a path that supplies power from the power supply unit 91 to the load 101. In the example in Figure 1, the power path 80 has a first power path 81 located on the power supply unit 91 side of the diode 71, and a second power path 82 located on the load 101 side of the diode 71. The first power path 81 is supplied with a voltage that is the same as or approximately the same as the output voltage of the power supply unit 91. One end of the first power path 81 is electrically connected to the positive terminal of the power supply unit 91 in a short-circuit configuration. The other end of the first power path 81 is electrically connected to the anode of the diode 71. The first power path 81 may be supplied with a relay or a fuse. One end of the second power path 82 is electrically connected to the cathode of the diode 71. In the example in Figure 1, the second power path 82 is short-circuited to one end of the load 101.

[0040] Diode 71 is an element interposed in the power path 80. Diode 71 allows current to flow from the first power path 81 to the second power path 82 in the power path 80, and blocks current from flowing from the second power path 82 to the first power path 81. Diode 71 has the function of preventing current from flowing from the second power path 82 to the first power path 81 when the voltage of the first power path 81 drops significantly lower than the voltage of the second power path 82 due to a failure condition described later.

[0041] 3. Details of the power supply control device The power supply control device 10 is included in the in-vehicle system 2 and is a device that controls the power supply from the energy storage unit 92. The power supply control device 10 is a backup device that can output power based on the energy storage unit 92. The power supply control device 10 includes a first conductive path 41, a second conductive path 42, a third conductive path 43, a fourth conductive path 44, a control unit 16, a voltage conversion unit 30, an element unit 52, a switch unit 60, a current detection unit 12, a voltage detection unit 14, and the like.

[0042] The first conductive path 41 is a conductive path electrically connected to one end of the element section 52. In the example in Figure 1, one end of the first conductive path 41 is short-circuited to one end of the element section 52, and the other end of the first conductive path 41 is short-circuited to the positive electrode, which is one end of the energy storage section 92. A voltage based on the output of the energy storage section 92 is applied to the first conductive path 41. In the example in Figure 1, the potential of the first conductive path 41, the potential of the source of the FET (Field Effect Transistor) constituting the element section 52, the potential of the anode of the diode 52B, and one end (positive electrode) of the energy storage section 92 are all at the same potential.

[0043] The second conductive path 42 is a conductive path electrically connected to the other end of the element section 52. The second conductive path 42 forms the current-carrying path between the element section 52 and the power line 80. In the example in Figure 1, one end of the second conductive path 42 is short-circuited to the other end of the element section 52, and the other end of the second conductive path 42 is short-circuited to the third conductive path 43. In the example in Figure 1, the potential of the second conductive path 42, the potential of the drain of the element section 52, the potential of the cathode of the diode 52B, and the potential of the third conductive path 43 are all at the same potential. The second conductive path 42 is electrically connected to a conductive path (third conductive path 43) located between the switch section 60 and the voltage conversion section 30. In Figure 1, the connection point between the second conductive path 42 and the third conductive path 43 is indicated by the symbol P1.

[0044] The third conductive path 43 is a conductive path positioned between the voltage conversion unit 30 and the switch unit 60. The third conductive path 43 is electrically connected to the voltage conversion unit 30 between the voltage conversion unit 30 and the power path 80. In the example shown in Figure 1, one end of the third conductive path 43 is electrically connected to the voltage conversion unit 30, and the other end of the third conductive path 43 is electrically connected to the switch unit 60.

[0045] The fourth conductive path 44 is a conductive path positioned between the switch unit 60 and the power path 80. In the example shown in Figure 1, one end of the fourth conductive path 44 is electrically connected to the switch unit 60, and the other end of the fourth conductive path 44 is electrically connected to the power path 80. In Figure 1, the connection point between the fourth conductive path 44 and the power path 80 is indicated by the symbol P2.

[0046] The element 52 is an element provided between the first conductive path 41 and the second conductive path 42. One end of the element 52 is electrically connected to the first conductive path 41. The other end of the element 52 is electrically connected to the second conductive path 42. The element 52 is allowed to allow current to flow through it to the power path 80, and is capable of blocking current from flowing through it to the energy storage unit 92. In the example in Figure 1, the element 52 is configured as an N-channel FET and has a diode 52B configured as a body diode and a switching unit 52A provided in parallel with the diode 52B. In the example in Figure 1, the switching unit 52A is the part of the element 52 configured as an FET that is not configured as a body diode, and is the part that allows bidirectional current flow when in the ON state and blocks bidirectional current flow when in the OFF state. Due to this configuration, a voltage based on the output of the energy storage unit 92 is applied to the anode of the diode 52B. The cathode of diode 52B is electrically connected to the second conductive path 42.

[0047] The switch section 60 is a switch provided between the third conductive path 43 and the power path 80. In the example shown in Figure 1, the switch section 60 has switch elements 61 and 62 configured as N-channel FETs. The drain of switch element 61 is electrically connected to the fourth conductive path 44. The body diode of switch element 61 is oriented so that the cathode faces the power path 80, and no current flows from the power path 80 to the third conductive path 43 through the body diode. The drain of switch element 62 is electrically connected to the third conductive path 43. The body diode of switch element 62 is oriented so that the cathode faces the third conductive path 43, and no current flows from the third conductive path 43 to the power path 80 through the body diode. In the example shown in Figure 1, the ON state of the switch section 60 means that both switch elements 61 and 62 are ON, and the OFF state of the switch section 60 means that both switch elements 61 and 62 are OFF. When the switch unit 60 is in the off state, both the switch elements 61 and 62 are in the off state, so the switch unit 60 blocks the flow of current from the power line 80 to the third conductive line 43. When the switch unit 60 is in the on state, both the switch elements 61 and 62 are in the on state, so the switch unit 60 allows current to flow through itself between the third conductive line 43 and the power line 80.

[0048] In the example shown in Figure 1, the second conductive path 42 and the third conductive path 43 are short-circuited without going through the switch 60, whether the switch 60 is in the ON state or the OFF state.

[0049] The voltage conversion unit 30 is a device capable of boosting or lowering the input voltage. In the example shown in Figure 1, the voltage conversion unit 30 is connected in parallel to the element unit 52 between the energy storage unit 92 and the power line 80. The voltage conversion unit 30 is composed of a known voltage conversion circuit, such as a DC-DC converter.

[0050] In the example shown in Figure 1, the voltage conversion unit 30 performs voltage conversion between the first conductive path 41 and the third conductive path 43. The voltage conversion unit 30 may perform a first conversion operation in which it steps down or steps up the DC voltage applied to the first conductive path 41 and applies the output voltage to the third conductive path 43. During the first conversion operation, the DC voltage applied to the first conductive path 41 is the input voltage based on the power from the energy storage unit 92. The voltage conversion unit 30 may also have a function to perform a second conversion operation in which it steps up or steps down the voltage applied to the third conductive path 43 and applies the voltage to the first conductive path 41, that is, a function to perform bidirectional voltage conversion. The operation of the voltage conversion unit 30 is controlled by the control unit 16. The voltage conversion unit 30 is equipped with a voltage sensor capable of detecting the voltage value of the third conductive path 43 and a current sensor capable of detecting the current value flowing through the third conductive path 43. The control unit 16 obtains information from these sensors to determine the current value flowing through the third conductive path 43 and the voltage value of the third conductive path 43.

[0051] In the example shown in Figure 2, the voltage conversion unit 30 comprises switch elements T1, T2, T3, and T4 arranged in a known H-bridge structure, and an inductor L, and functions as a so-called bidirectional step-up / step-down DC-DC converter. Switch elements T1 and T2 are connected in series between the first conductive path 41 and the ground 83. One end of switch element T1 is electrically connected to the first conductive path 41 in a configuration that is short-circuited to the first conductive path 41. The other end of switch element T1 is electrically connected to one end of switch element T2 and one end of inductor L in a configuration that is short-circuited to one end of switch element T2 and one end of inductor L. The other end of switch element T2 is electrically connected to the ground 83 in a configuration that is short-circuited to the ground 83. Switch elements T3 and T4 are connected in series between the third conductive path 43 and the ground 83. One end of switch element T3 is electrically connected to the third conductive path 43 in a configuration that is short-circuited to the third conductive path 43. The other end of switch element T3 is short-circuited to one end of switch element T4 and the other end of inductor L, thereby electrically connecting to one end of switch element T4 and the other end of inductor L. The other end of switch element T4 is short-circuited to ground 83, thereby electrically connecting to ground 83. Switch elements T1, T2, T3, and T4 are configured as N-channel type FETs.

[0052] The control unit 16 is a device that controls the voltage conversion unit 30, the element unit 52, and the switch unit 60. The control unit 16 has an information processing device that has information processing functions, calculation functions, control functions, etc., and may be composed of this information processing device, or it may be composed of the information processing device and other devices. For example, the control unit 16 may have a common control device that controls the voltage conversion unit 30, the element unit 52, and the switch unit 60, or each of the voltage conversion unit 30, the element unit 52, and the switch unit 60 may be controlled by separate devices.

[0053] The voltage detection unit 14 is a circuit that provides the control unit 16 with a detection value (for example, an analog voltage value) that can identify the voltage applied to the power line 80. The voltage detection unit 14 may be a circuit that inputs the same voltage value to the control unit 16 as the voltage applied to the power line 80, or it may be a circuit that inputs a value proportional to the voltage applied to the power line 80 to the control unit 16. For example, the voltage detection unit 14 is a voltage divider circuit, and the value obtained by dividing the voltage applied to the first power line 81 by the voltage divider circuit is input to the control unit 16 as the detection value. The control unit 16 identifies the voltage applied to the first power line 81 based on the detection value input from the voltage detection unit 14.

[0054] The current detection unit 12 is a current sensor that detects the value of the current flowing through the fourth conductive path 44. The detected value input from the current detection unit 12 to the control unit 16 is information that can identify the value of the current flowing through the fourth conductive path 44. The control unit 16 identifies the value of the current flowing through the fourth conductive path 44 based on the detected value input from the current detection unit 12.

[0055] 4. Operation of the power supply control device The following explanation concerns the control for backup operations performed by the power supply control device 10. Figure 3 is a flowchart showing the control flow for backup operations.

[0056] The control unit 16 starts the backup operation control shown in Figure 3 when a predetermined start condition is met. The above "start condition" may be, for example, "the vehicle enters a starting state," or it may be any other condition. In the representative example described below, the control unit 16 determines that the above start condition is met when the vehicle on which the in-vehicle system 2 is installed enters a starting state, and starts the backup operation control shown in Figure 3. When the vehicle enters a starting state, for example, when a start switch such as the ignition switch in a hybrid vehicle or the power switch in an electric vehicle is turned ON.

[0057] When the control unit 16 starts the backup operation control shown in Figure 3, it determines that the system is in a normal state (not in a failure state) and stops the voltage conversion unit 30. This reduces the power consumption required to operate the voltage conversion unit 30 (more specifically, the switch elements T1, T2, T3, T4). The voltage conversion unit 30 is stopped, for example, with the current flow from the third conductive path 43 to the ground 83 side via the voltage conversion unit 30 blocked. More specifically, the voltage conversion unit 30 is stopped with all the switch elements T1, T2, T3, T4 constituting the voltage conversion unit 30 turned off. This prevents the power path 80 from being short-circuited to the ground 83 in the normal state, regardless of the state of the switch unit 60.

[0058] With the voltage conversion unit 30 stopped, the control unit 16 determines in step S1 whether a predetermined failure state has occurred. A failure state is an abnormal state in which the power supply from the power supply unit 91 to the power line 80 has decreased to a predetermined standard or has stopped. Various known methods can be used to determine the failure state. In the representative example described below, a failure state is defined as a state in which the voltage of the first power line 81 has fallen below a threshold. In this case, the threshold is a value that is smaller than the output voltage of the power supply unit 91 when fully charged and is 0V or greater.

[0059] If the control unit 16 determines in step S1 that no loss condition has occurred, it makes a No determination in step S1 and repeats the determination in step S1. In the example in Figure 3, after the control in Figure 3 is started, as long as no loss condition has occurred, , place The failure state is continuously checked until a predetermined termination condition is met. In the representative example described below, the control unit 16 keeps both the switch unit 60 and the element unit 52 in the off state and stops the voltage conversion unit 30 while the failure state is not occurring.

[0060] If the control unit 16 determines in step S1 that a power failure has occurred (if the answer is Yes in step S1), it switches the switch unit 60 to the ON state in step S2, switches the element unit 52 to the ON state in step S3, and causes the voltage conversion unit 30 to start the first conversion operation in step S4. In this way, the control unit 16 keeps the voltage conversion unit 30 stopped when the power supply from the power supply unit 91 to the power line 80 is in a normal state and not in a power failure state, and causes the voltage conversion unit 30 to start the first conversion operation when a power failure occurs.

[0061] In step S2, the control unit 16 turns on the switch unit 60, and then in step S3, it switches the element unit 52 to the ON state. When this switching is performed, the element unit 52 is allowed to be energized via the switching unit 52A and via the diode 52B, enabling energization with reduced losses. The control by the control unit 16 to switch the element unit 52 to the ON state may be performed simultaneously with step S2, or before step S2.

[0062] In this embodiment, when the voltage of the second conductive path 42 is less than or equal to the second value in the failure state, current flows from the energy storage unit 92 to the power path 80 via the element unit 52. The second value is the first subtraction value obtained by subtracting the voltage drop caused by the switching unit 52A and diode 52B from the voltage applied to the first conductive path 41 when the switching unit 52A is ON. The second value is the second subtraction value obtained by subtracting the voltage drop caused by diode 52B from the voltage applied to the first conductive path 41 when the switching unit 52A is OFF. In this embodiment, the first value is greater than the second value, specifically, the first value is greater than both the first subtraction value and the second subtraction value. The first value is, for example, 15V. The second subtraction value is, for example, 10.8V during the period before the element unit 52 switches to the ON state in step S3.

[0063] In the control unit 16, the part that executes the control in step S3 is step S 2The part that performs the control of step S4 may be different from the part that performs the control of step S3. If a dedicated part is provided for performing the control of step S3, that dedicated part may be configured to detect the current flowing through diode 52B, keep the element unit 52 in the off state when no current is flowing through diode 52B, and execute step S3 to switch the element unit 52 to the on state when current flows through diode 52B.

[0064] In step S3, the control unit 16 switches the element unit 52 to the ON state, and then in step S4, it instructs the voltage conversion unit 30 to start a first conversion operation (boost or buck operation) to apply an output voltage of the target value to the third conductive path 43, with the first value as the target value. In this way, when a failure occurs, the control unit 16 instructs the voltage conversion unit 30 to start a first conversion operation to apply an output voltage of the first value to the third conductive path 43. When the control unit 16 instructs the voltage conversion unit 30 to start the first conversion operation with the first value as the target value in step S4, it continues the conversion operation with the first value as the target value until a predetermined termination condition is met or the process in step S7 is executed. The predetermined termination condition is, for example, when the vehicle's start switch is turned off. When the predetermined termination condition is met, the control in Figure 3 is forcibly terminated.

[0065] When the voltage conversion unit 30 starts voltage conversion, the current from the voltage conversion unit 30 gradually increases, but if the load response of the voltage conversion unit 30 is low, it is difficult to supply a large current immediately. For this reason, immediately after the element unit 52 is switched on in step S3, current flows into the second conductive path 42 via the element unit 52. In other words, immediately after the element unit 52 is switched on in step S3, the voltage conversion unit 30 cannot output a very large current, but a large current can flow through the element unit 52. Immediately after the element unit 52 is switched on in step S3, a voltage is applied to the second conductive path 42 and the third conductive path 43 that is obtained by subtracting the voltage drop Vf caused by the diode 52B from the output voltage of the energy storage unit 92 (voltage applied to the first conductive path 41) at the time the element unit 52 was switched on in step S3. As time passes after the element unit 52 is switched to the ON state, the voltage applied to the third conductive path 43 by the voltage conversion unit 30 increases, and the current supplied to the third conductive path 43 by the voltage conversion unit 30 also increases.

[0066] The control unit 16 may initiate voltage conversion in the voltage conversion unit 30 simultaneously with step S2, or before step S2. The control unit 16 may initiate voltage conversion in the voltage conversion unit 30 simultaneously with step S3, or before step S3.

[0067] After step S4, the control unit 16 determines in step S5 whether a predetermined condition has been met. After steps S2, S3, and S4 are performed, the control unit 16 repeatedly determines No in step S5 until the predetermined condition is met, and repeats the determination in step S5. The predetermined condition is, for example, "the voltage of the second conductive path has reached a predetermined value equal to or greater than the voltage of the first conductive path." In a typical example, the predetermined value is the voltage of the first conductive path. In other words, in a typical example, the predetermined condition is "the voltage of the second conductive path has reached a value equal to or greater than the voltage of the first conductive path." The predetermined value may be a different value that is greater than the voltage of the first conductive path.

[0068] If the control unit 16 determines that the predetermined conditions have been met after steps S2, S3, and S4 have been performed (if the answer is Yes in step S5), it switches the element unit 52 to the OFF state in step S6. In other words, the element unit 52 is switched to the OFF state immediately after the voltage of the second conductive path 42 reaches the voltage of the first conductive path 41. When such a switch is made, the current flow in the element unit 52 via the switching unit 52A is cut off, and only current flow via the diode 52B is permitted. In this way, the power supply control device 10 operates to cut off the current flow in the element unit 52 from the second conductive path 42 to the energy storage unit 92 when the predetermined conditions have been met after the above-mentioned failure state has occurred.

[0069] In step S6, the control unit 16 switches the element unit 52 to the off state, and then in step S7, it switches the target value of the voltage conversion unit 30 to a third value that is smaller than the first value. In this way, when a failure occurs, the control unit 16 causes the voltage conversion unit 30 to perform a first conversion operation in which it applies an output voltage of the first value to the third conductive path 43, and then causes the voltage conversion unit 30 to perform a first conversion operation in which it applies an output voltage of the third value to the third conductive path 43. The third value is set in step S 7 The third value is greater than the second value at the time of switching to the third value (the value obtained by subtracting the voltage drop at the element section 52 from the voltage of the first conductive path 41), and greater than the second value thereafter. Therefore, the inflow of current through the element section 52 is suppressed. The timing at which the control unit 16 executes step S7 may be when the voltages of the second conductive path 42 and the third conductive path 43 reach the first value, or it may be after a predetermined time has elapsed since the voltages of the second conductive path 42 and the third conductive path 43 reached the first value. The third value is, for example, 10.2V.

[0070] Thus, when the state changes from a normal state (not a failure state) to a failure state, the control unit 16 turns on the switch unit 60, turns on the switching unit 52A, and causes the voltage conversion unit 30 to start voltage conversion. After switching the switch unit 60 to the ON state, the control unit 16 operates to switch the switching unit 52A to the OFF state when a predetermined condition is met while the voltage conversion unit 30 is performing the first conversion operation. Furthermore, after switching the switching unit 52A to the OFF state, the control unit 16 causes the voltage conversion unit 30 to perform a first conversion operation which applies an output voltage of a third value to the third conductive path 43. The third value is set to be greater than the second subtraction value obtained after the target value was switched to the third value in step S7.

[0071] 5. Examples of effects The power supply control device 10 can utilize both the path via the element unit 52 and the path via the voltage conversion unit 30 when performing backup operations to supply power based on the energy storage unit 92. For example, the power supply control device 10 can quickly supply power using the path via the element unit 52 when sufficient power cannot be supplied through the path via the voltage conversion unit 30. On the other hand, if the output voltage of the energy storage unit 92 decreases, the power supply control device 10 can perform a boost operation using the voltage conversion unit 30 to apply the desired output voltage to the third conductive path 43 as a backup. Furthermore, when the switch unit 60 is in the off state, the power supply control device 10 can block the flow of current from the power path 80 to the voltage conversion unit 30, and when the switch unit 60 is in the on state, it can reduce losses when current flows towards the power path 80.

[0072] The power supply control device 10 is configured such that when the voltage of the second conductive path 42 is below the second value in a power failure state, current flows from the energy storage unit 92 to the power line 80 via the element unit 52. In other words, when the output of the voltage conversion unit 30 has not risen to the extent that "the voltage of the second conductive path 42 exceeds the second value", power based on the energy storage unit 92 can be supplied to the power line 80 via the element unit 52, so that current can be supplemented by the path via the element unit 52 when the output of the voltage conversion unit 30 is low. Furthermore, the control unit 16 can also turn off the switch unit 60 when the power supply from the power supply unit 91 to the power line 80 is in a normal state and not in the power failure state described above, thereby blocking the flow of current from the power line 80 to the voltage conversion unit 30. Furthermore, after the above failure state occurs, the element section 52 can block the flow of current from the second conductive path 42 to the energy storage section 92. Therefore, while this blocking function is active, it is possible to prevent current based on the output from the voltage conversion section 30 from flowing from the second conductive path 42 to the energy storage section 92.

[0073] When a power failure occurs, the power supply control device 10 can perform voltage conversion to apply an output voltage of a first value to the third conductive path 43, and then switch the voltage conversion to apply an output voltage of a third value that is lower than the first value. Therefore, after a certain amount of time has elapsed, the power supply control device 10 can suppress the voltage output by the voltage conversion unit 30 and reduce the output energy.

[0074] When a power failure occurs, the power supply control device 10 performs voltage conversion to apply an output voltage of a first value greater than the second value mentioned above, thereby enabling it to bring the voltage of the third conductive path 43 closer to a relatively high target voltage (first value) as quickly as possible. Furthermore, after a certain amount of time has elapsed since the power failure, the power supply control device 10 can suppress output energy by reducing the voltage output by the voltage conversion unit 30 to a third value smaller than the first value mentioned above. Since the third value is greater than the second value, the inflow of current into the second conductive path 42 via the element unit 52 is suppressed.

[0075] The power supply control device 10 is configured such that a diode 52B and a switch 52A are provided in parallel in the element section 52, with the anode of the diode 52B connected to the first conductive path 41 and the cathode connected to the second conductive path 42. Therefore, in the element section 52, even when the switch 52A is in the off state, if the voltage of the second conductive path 42 is lower than the voltage of the first conductive path 41 by a certain value or more, current is continuously permitted to flow from the first conductive path 41 to the second conductive path 42, and when the switch 52A is in the on state, power is permitted to flow through the switch 52A. Furthermore, the power supply control device 10 turns on the switch 52A when the state changes from normal to failure state, thereby reducing losses in the element section 52 and enabling the supply of more power through the element section 52 at an earlier stage. Furthermore, after switching the switch section 60 to the on state, the power supply control device 10 switches the switch 52A to the off state according to the fulfillment of predetermined conditions during the first conversion operation. Therefore, the power supply control device 10 can prevent current from flowing backward in the element section 52 after the first conversion operation has proceeded until a predetermined condition is met. Furthermore, after switching the switching unit 52A to the off state, the power supply control device 10 causes the voltage conversion unit 30 to perform a first conversion operation in which it applies an output voltage of a third value (a value smaller than the first value and larger than the second subtraction value) to the third conductive path 43. Therefore, after a certain amount of time has elapsed, the power supply control device 10 can continue to supply power by suppressing the forward current in the diode 52B and by the output operation of the voltage conversion unit 30 with suppressed energy.

[0076] The above predetermined condition may also be that the voltage conversion unit 30 outputs an output voltage of a first value. In this case, the power supply control device 10 can continue to supply power via the switching unit 52A after a failure state until the output voltage applied to the third conductive path 43 rises to the first value, and after the output voltage rises to the first value, it can reliably prevent reverse current in the element unit 52.

[0077] <Example of modification of the first embodiment 1> In the representative example of the first embodiment, an example of a predetermined condition was shown, but the above predetermined condition may be "a predetermined time has elapsed since the voltage conversion unit 30 began outputting current to the third conductive path 43 after the above-mentioned failure state." In modified example 1, the contents can be the same as in the first embodiment except for the predetermined condition.

[0078] This power supply control device 10 can continue to supply power via the switching unit 52A after the aforementioned failure state, until a predetermined time has elapsed from the time the voltage conversion unit 30 starts outputting current, and after the predetermined time has elapsed, it can reliably prevent reverse current in the element unit 52.

[0079] <Example of modification of the first embodiment 2> In the representative example of the first embodiment, an example of a predetermined condition is shown, but the above predetermined condition may also be "the current flowing through the element 52 has reached or below the lower limit." In modified example 2, the contents can be the same as in the first embodiment except for the predetermined condition.

[0080] This power supply control device 10 can allow energization through the switching unit 52A after the aforementioned failure state until the current flowing through the element unit 52 falls below the lower limit, and when the current flowing through the element unit 52 falls below the lower limit, it can reliably prevent reverse current in the element unit 52.

[0081] <Example of modification of the first embodiment 3> In the representative example of the first embodiment, an example of a predetermined condition was shown, but the predetermined condition may also be "the current output by the voltage conversion unit 30 to the third conductive path 43 after the above-mentioned failure state has reached a reference value or higher." In modified example 3, the contents can be the same as in the first embodiment except for the predetermined condition.

[0082] This power supply control device 10 can allow current to flow through the switching unit 52A after the above-mentioned failure state until the current output by the voltage conversion unit 30 to the third conductive path 43 reaches a reference value or higher, and when the current output by the voltage conversion unit 30 to the third conductive path 43 reaches a reference value or higher, it can reliably prevent reverse current in the element unit 52.

[0083] <Second Embodiment> The following description relates to a second embodiment. The power supply control device 210 of the second embodiment shown in Figure 4 differs from the power supply control device 10 of the first embodiment only in that the switch element 62 is omitted from the configuration in Figure 1; otherwise, it is identical to the power supply control device 10 of the first embodiment.

[0084] As shown in Figure 4, in the power supply control device 210 of the second embodiment, the switch element 61 corresponds to the switch unit. The body diode of the switch element 61 corresponds to an example of the second diode, and the anode of this body diode is electrically connected to the third conductive path 43, and the cathode is electrically connected to the power path 80. The cathode of this body diode may be short-circuited so that it is at the same potential as the second power path 82, or it may be connected via the current detection unit 12 as shown in Figure 4. In the configuration of Figure 4, when the switch unit 60 is in the off state and the voltage of the power path 80 drops by a certain value or more below the voltage of the third conductive path 43, current flows from the third conductive path 43 to the power path 80 through the body diode. The backup operation control performed by the power supply control device 210 of the second embodiment is the same as that of the first embodiment and is performed in the flow shown in Figure 3.

[0085] <Third Embodiment> The following description relates to a third embodiment. The power supply control device 310 of the third embodiment shown in Figure 5 differs from the power supply control device 10 of the first embodiment only in that the position of the switch unit 60 has been changed from the configuration in Figure 1; in all other respects, it is the same as the power supply control device 10 of the first embodiment.

[0086] In the power supply control device 310 shown in Figure 5, the other end of the second conductive path 42 is electrically connected to the fourth conductive path 44. In this configuration, when the switch unit 60 is ON, the second conductive path 42 and the third conductive path 43 are short-circuited via the switch unit 60. The backup operation control performed by the power supply control device 310 in the third embodiment is the same as in the first embodiment and is carried out in the flow shown in Figure 3.

[0087] <Fourth Embodiment> The following description relates to a fourth embodiment. The power supply control device 410 of the fourth embodiment shown in Figure 6 differs from the power supply control device 10 of the first embodiment only in that the switch unit 60 is omitted from the configuration in Figure 1; in all other respects, it is the same as the power supply control device 10 of the first embodiment.

[0088] In the power supply control device 410 shown in Figure 6, the second conductive path 42 and the third conductive path 43 are short-circuited. The second conductive path 42 and the third conductive path 43 are electrically connected to the power path 80 in a short-circuited configuration. In the configuration of Figure 6, when the voltage of the power path 80 decreases, the voltage of the second conductive path 42 also decreases, and when it falls below the second value, current flows from the energy storage unit 92 to the power path 80 via the diode 52B of the element unit 52. In other words, the power supply control device 410 shown in Figure 6 can supply power more quickly by utilizing the path via the element unit 52 when the voltage of the second conductive path 42 falls below the second value in a power failure state.

[0089] The backup operation control performed by the power supply control device 410 of the fourth embodiment is a process that omits step S2 in the process shown in Figure 3. In the power supply control device 410 of Figure 6, when the voltage of the second conductive path 42 falls below the second value in a failure state, power supply can be immediately started via the diode 52B even before the switching unit 52A is switched to the ON state in step S3. Furthermore, by switching the switching unit 52A to the ON state, the power supply control device 410 can supply more power via the element unit 52 while reducing losses in the element unit 52. Furthermore, in step S4, the power supply control device 410 starts the conversion operation of the voltage conversion unit 30. Therefore, when the output voltage of the energy storage unit 92 decreases, the voltage conversion unit 30 can perform a boost operation and perform a backup operation to apply the desired output voltage to the third conductive path 43. Furthermore, in the event of a power failure, the power supply control device 410 can perform voltage conversion to apply an output voltage of a first value greater than the second value described above, thereby bringing the voltage of the third conductive path 43 closer to a relatively high target voltage (the first value).

[0090] <Fifth Embodiment> The following description relates to the fifth embodiment. The power supply control device 510 of the fifth embodiment shown in Figure 7 has a configuration that adds the switch element 62 shown in Figure 1 to the configuration in Figure 6, and is otherwise identical to the power supply control device 410 of the fourth embodiment.

[0091] As shown in Figure 7, in the power supply control device 510 of the fifth embodiment, the switch element 62 corresponds to the switch unit. In the power supply control device 410 of the fourth embodiment, for example, in a configuration where the output voltage of the energy storage unit 92 is higher than the output voltage of the power supply unit 91, even though there is no power failure, current may flow from the energy storage unit 92 to the power line 80 via the diode 52B, causing the power of the energy storage unit 92 to be consumed. In contrast, the power supply control device 510 shown in Figure 7 can block the flow of current from the energy storage unit 92 to the power line 80 via the diode 52B using the body diode of the switch element 62. Then, after a power failure occurs, in step S2 of Figure 3, the switch element 62 corresponding to the switch unit is switched to the ON state, so that power is quickly supplied from the energy storage unit 92 to the power line 80 via the diode 52B.

[0092] <Sixth Embodiment> The following description relates to the sixth embodiment. In the first embodiment, the power supply control device 10 was configured to keep the voltage conversion unit 30 stopped under normal conditions. In contrast, the power supply control device 610 of the sixth embodiment shown in Figure 8 is configured to cause the voltage conversion unit 30 to perform a second conversion operation under normal conditions. Furthermore, in the power supply control device 610 of the sixth embodiment, the switch unit 60 is omitted from the configuration in Figure 1, and the element unit 52 is replaced with an element unit 652.

[0093] The element section 652 includes a diode 653 and a reverse current prevention switch 654. The diode 653 and the reverse current prevention switch 654 are arranged in series with each other between the first conductive path 41 and the second conductive path 42. The diode 653 blocks the flow of current through it to the first conductive path 41 and allows the flow of current through it to the second conductive path 42.

[0094] The reverse current prevention switch 654 is configured as an N-channel FET. One end of the reverse current prevention switch 654 (specifically the drain) is electrically connected to the first conductive path 41. A voltage based on the output of the energy storage unit 92 is applied to one end of the reverse current prevention switch 654 (specifically the drain). The other end of the reverse current prevention switch 654 (specifically the source) is electrically connected to the anode of the diode 655. The cathode of the diode 655 is electrically connected to the second conductive path 42. When the reverse current prevention switch 654 is in the off state, it blocks the flow of current to the second conductive path 42 through itself, and when it is in the on state, it allows the flow of current to the second conductive path 42 through itself.

[0095] The reverse current prevention switch 654 includes a diode 655 configured as a body diode and a switching unit 656 provided in parallel with the diode 655. The cathode of the diode 655 and one end of the switching unit 656 are electrically connected to the first conductive path 41. A voltage based on the output of the energy storage unit 92 is applied to the cathode of the diode 655 and one end of the switching unit 656. The anode of the diode 655 and the other end of the switching unit 656 are electrically connected to the anode of the diode 653. The cathode of the diode 653 is electrically connected to the second conductive path 42. The switching unit 656 is the part of the reverse current prevention switch 654 configured as an FET, excluding the part configured as a body diode, and is the part that allows bidirectional current flow when in the ON state and blocks bidirectional current flow when in the OFF state. When the switching unit 656 is ON, it means when the reverse current prevention switch 654 is ON. When the opening / closing part 656 is in the off state, it means that the backflow prevention switch 654 is in the off state.

[0096] One end of the reverse current prevention switch 654 (i.e., the cathode of diode 655 and one end of the switching part 656) constitutes one end of the element section 652. The cathode of diode 653 constitutes the other end of the element section 652. One end of the element section 652 is electrically connected to the first conductive path 41, and the other end of the element section 652 is electrically connected to the second conductive path 42.

[0097] The element 652 allows current to flow through it to the power line 80 when the reverse current prevention switch 654 is ON, while the diode 653 blocks current from flowing through it to the energy storage unit 92. The element 652 blocks the current in both directions when the reverse current prevention switch 654 is OFF.

[0098] In the normal state, the control unit 16 causes the voltage conversion unit 30 to perform a second conversion operation. This charges the energy storage unit 92. In this embodiment, the second conversion operation is a voltage boosting operation. In the normal state, the control unit 16 turns off the reverse current prevention switch 654. This allows the power supply control device 610 to prevent the current supplied from the voltage conversion unit 30 to the first conductive path 41 from flowing back to the second conductive path 42 and the third conductive path 43 via the element unit 652. The control unit 16 causes the voltage conversion unit 30 to perform the second conversion operation until it enters a failure state, thereby charging the energy storage unit 92.

[0099] When a failure occurs, the control unit 16 switches the reverse current prevention switch 654 to the ON state and causes the voltage conversion unit 30 to start the first conversion operation. This immediately starts the supply of power to the power line 80 via the element unit 652. Similar to step S4 in Figure 3, the control unit 16 causes the voltage conversion unit 30 to start the first conversion operation to apply an output voltage of the target value to the third conductive line 43, with the first value as the target value. After that, similar to step S5 in Figure 3, the control unit 16 determines whether a predetermined condition has been met. If the control unit 16 determines that a predetermined condition has been met, it switches the reverse current prevention switch 654 to the OFF state and, similar to step S7 in Figure 3, switches the target value of the voltage conversion unit 30 to a third value that is smaller than the first value.

[0100] The power supply control device 610 in Figure 8 causes the voltage conversion unit 30 to perform a second conversion operation under normal conditions, and causes the voltage conversion unit 30 to start a first conversion operation when a failure occurs. Therefore, the power supply control device 610 charges the energy storage unit 92 under normal conditions, and when a failure occurs, it can supply the voltage adjusted by the voltage conversion unit 30 to the power line 80. Moreover, under normal conditions, the power supply control device 610 prevents the current supplied from the voltage conversion unit 30 to the first conductive line 41 from flowing back to the second conductive line 42 and the third conductive line 43 via the element unit 652 using the reverse current prevention switch 654. Then, when a failure occurs, the power supply control device 610 can immediately supply power to the power line 80 via the element unit 652 by switching the reverse current prevention switch 654 to the ON state.

[0101] <Other Embodiments> This disclosure is not limited to the embodiments described above and in the drawings. For example, any combination of the features of the embodiments described above or below is possible as long as it does not contradict each other. Furthermore, any feature of the embodiments described above or below may be omitted unless explicitly stated as essential. In addition, the embodiments described above may be modified as follows.

[0102] In the embodiment described above, the energy storage unit 92 is provided outside the power supply control device 10, but the energy storage unit 92 may also be included in the power supply control device 10.

[0103] In the embodiment described above, the switch section 60 was composed of an FET, but the switch section may be composed of a semiconductor switch other than an FET, or it may be composed of a mechanical relay.

[0104] In the embodiment described above, the switching elements T1, T2, T3, and T4 constituting the voltage conversion section were composed of FETs, but they may be composed of semiconductor switches other than FETs.

[0105] In the embodiment described above, a failure state is defined as a voltage drop in the first power line 81 below a threshold, but the system is not limited to this example. For example, a failure state may be defined as a voltage drop in the first power line 81 that exceeds a specified value within a predetermined time, or it may be determined by other methods.

[0106] In the embodiment described above, a diode 71 is provided, but a switch such as an FET may be provided instead of the diode 71. In this case, it is sufficient that the switch is configured to immediately shut off when a failure occurs.

[0107] In the embodiment described above, the element section 52 is composed of an FET, but a diode may be provided instead of the FET, and the element section may be configured such that the anode of the diode is connected to the first conductive path 41 and the cathode is connected to the second conductive path 42. In this case, the processes of steps S3 and S6 in the control shown in Figure 3 can be omitted.

[0108] In the embodiment described above, the second conductive path 42 and the third conductive path 43 are short-circuited, either via or without the switch, when the switch unit 60 is in the ON state. The second value described above is the value obtained by subtracting the voltage drop that occurs in the element unit 52 when current flows from the first conductive path 41 to the second conductive path 42, from the voltage value applied to the first conductive path 41. In the embodiment described above, in such a configuration, the third value is smaller than the first value and larger than the second value. However, the embodiment is not limited to this example, and the third value may be smaller than the first value and smaller than the second value. Specifically, if the second value is the value obtained by subtracting "the voltage drop that occurs in the element unit 52 when current flows from the first conductive path 41 to the second conductive path 42 when the element unit 52 is in the ON state" from the voltage value applied to the first conductive path 41, the third value may be smaller than this second value. In this example, the same hardware configuration as any of the embodiments described above may be adopted, and the process in step S7 of Figure 3 may be modified so that the third value is smaller than the second value, or as follows. For example, the element section 52 may be modified from the configuration in Figure 1 of the first embodiment to a configuration in which bidirectional current flow is interrupted when it is in the off state and bidirectional current flow is allowed when it is in the on state (for example, a configuration similar to that of the switch section 60), and then in step S6 of Figure 3, the element section may be turned off to interrupt bidirectional current flow in the element section, and then in step S7, the third value may be modified so that it is smaller than the first value and smaller than the second value. In this example, after a certain amount of time has elapsed since the failure state, the output energy can be suppressed by limiting the voltage output by the voltage conversion section to the third value, and the output energy can be further suppressed by making the third value smaller than the second value. At that time, the current flow from the first conductive path 41 to the second conductive path 42 is interrupted in the element section.

[0109] In the sixth embodiment described above, the second conversion operation was a boost operation, but it may also be a buck operation. In this case, the element section 652 may be configured without the reverse current prevention switch 654. For example, the element section 652 may consist only of the diode 653, or it may have the same configuration as the element section 52 described in the first embodiment.

[0110] In the sixth embodiment described above, the reverse current prevention switch 654 was positioned on the first conductive path 41 side of the diode 653, but the diode 653 may also be positioned on the first conductive path 41 side of the reverse current prevention switch 654. In this case, the output voltage of the energy storage unit 92 may be applied to the anode of the diode 653. The other end of the diode 653 may be electrically connected to one end of the reverse current prevention switch 654. The other end of the reverse current prevention switch 654 may be electrically connected to the second conductive path 42.

[0111] The embodiments disclosed herein should be considered in all respects to be illustrative and not restrictive. The scope of the present invention is not limited to the embodiments disclosed herein, but is indicated by the claims, and all modifications within the meaning and scope of the claims are intended to be included. [Explanation of symbols]

[0112] 2…In-vehicle systems 3. In-vehicle power supply system 10... Power supply control device 12...Current detection unit 14...Voltage detection unit 16…Control Unit 30...Voltage conversion section 41…First conductive path 42...Second conductive circuit 43…Third conductive circuit 44…Fourth conductive circuit 52... Element section 52A...Opening / closing section 52B…diode 60... Switch section 61…Switching element 62…Switching element 71…Diode 80…Power line 81…1st power path 82…Second power path 83... Ground 91...Power supply section 92... Energy storage unit 101... Load 210... Power supply control device 310... Power supply control device 410... Power supply control device 510... Power supply control device 610... Power supply control device 652... Element section 653…diode 654...Backflow prevention switch 655…diode 656...Opening / Closing Part L...Inductor T1…Switch element T2…Switch element T3…Switch element T4…Switch element

Claims

1. A power supply control device is included in an in-vehicle system comprising a power supply unit that supplies power, a power path which is a path through which power based on the power supply unit is transmitted, and a power storage unit different from the power supply unit, and controls the power supply from the power storage unit, A first conductive path to which a voltage based on the output of the energy storage unit is applied, An element portion having one end electrically connected to the first conductive path, A second conductive path is electrically connected to the other end of the element portion and forms a current-carrying path between the element portion and the power line, A voltage conversion unit connected in parallel to the element unit between the energy storage unit and the power line, Between the voltage conversion unit and the power line, a third conductive path is electrically connected to the voltage conversion unit, A control unit that controls the voltage conversion unit, Equipped with, The voltage conversion unit performs a first conversion operation to increase or decrease the voltage applied to the first conductive path and apply the output voltage to the third conductive path, and a second conversion operation to increase or decrease the voltage applied to the third conductive path and apply the output voltage to the first conductive path. The element portion is designed to allow current to flow through it to the power line side, and to be capable of blocking current from flowing through it to the energy storage portion side. The control unit either stops the voltage converter or causes the voltage converter to perform the second conversion operation when the power supply from the power unit to the power line is in a normal state and not in a state of power failure, and causes the voltage converter to start the first conversion operation when the power failure occurs. Furthermore, when the failure state occurs, the control unit causes the voltage conversion unit to start the first conversion operation so as to apply an output voltage of the first value to the third conductive path. In the aforementioned failure state, if the voltage of the second conductive path is less than or equal to the second value, current flows from the energy storage unit side through the element unit to the power path side. At least after the aforementioned failure state occurs, the element portion is prevented from flowing current from the second conductive path side to the energy storage portion side, and the element portion is allowed to flow current from the energy storage portion side to the second conductive path side. Furthermore, when the failure state occurs, the control unit causes the voltage conversion unit to start the first conversion operation of applying the output voltage of the first value to the third conductive path, and then causes the voltage conversion unit to perform the first conversion operation of applying the output voltage of a third value smaller than the first value to the third conductive path. Power supply control device.

2. The second conductive path and the third conductive path are short-circuited. The second value is the value obtained by subtracting the value of the voltage drop occurring in the element from the value of the voltage applied to the first conductive path. The first value is greater than the second value. The third value is less than the first value and greater than the second value. The power supply control device according to claim 1.

3. The second conductive path and the third conductive path are short-circuited. The second value is obtained by subtracting the value of the voltage drop that occurs in the element when current flows from the first conductive path to the second conductive path in the element from the value of the voltage applied to the first conductive path. The third value is smaller than the first value and smaller than the second value. The power supply control device according to claim 1.

4. A power supply control device included in an in-vehicle system comprising a power supply unit that supplies power, a power path which is a path through which power based on the power supply unit is transmitted, and a power storage unit different from the power supply unit, wherein the power supply control device controls the power supply from the power storage unit, A first conductive path to which a voltage based on the output of the energy storage unit is applied, An element portion having one end electrically connected to the first conductive path, A second conductive path is electrically connected to the other end of the element portion and forms a current-carrying path between the element portion and the power line, A voltage conversion unit connected in parallel to the element unit between the energy storage unit and the power line, Between the voltage conversion unit and the power line, a third conductive path is electrically connected to the voltage conversion unit, A control unit that controls the voltage conversion unit, Equipped with, The voltage conversion unit performs a first conversion operation to increase or decrease the voltage applied to the first conductive path and apply the output voltage to the third conductive path, and a second conversion operation to increase or decrease the voltage applied to the third conductive path and apply the output voltage to the first conductive path. The element portion is designed to allow current to flow through it to the power line side, and to be capable of blocking current from flowing through it to the energy storage portion side. The control unit either stops the voltage converter or causes the voltage converter to perform the second conversion operation when the power supply from the power unit to the power line is in a normal state and not in a state of power failure, and causes the voltage converter to start the first conversion operation when the power failure occurs. Furthermore, when the failure state occurs, the control unit causes the voltage conversion unit to start the first conversion operation so as to apply an output voltage of the first value to the third conductive path. In the aforementioned failure state, if the voltage of the second conductive path is less than or equal to the second value, current flows from the energy storage unit side through the element unit to the power path side. At least after the aforementioned failure state occurs, the flow of current from the second conductive path side to the energy storage side in the element section is interrupted. Furthermore, when the failure state occurs, the control unit causes the voltage conversion unit to start the first conversion operation of applying the output voltage of the first value to the third conductive path, and then causes the voltage conversion unit to perform the first conversion operation of applying the output voltage of a third value smaller than the first value to the third conductive path. The second conductive path and the third conductive path are short-circuited. The second value is the value obtained by subtracting the value of the voltage drop occurring in the element from the value of the voltage applied to the first conductive path. The first value is greater than the second value. The third value is less than the first value and greater than the second value. The element portion comprises a diode and a switching portion provided in parallel with the diode. A voltage based on the output of the energy storage unit is applied to the anode of the diode. The cathode of the diode is electrically connected to the second conductive path. The aforementioned switching unit allows bidirectional energization when it is in the ON state. The second value is a first subtraction value obtained by subtracting the voltage drop caused by the switching unit and the diode from the voltage applied to the first conductive path when the switching unit is ON, and a second subtraction value obtained by subtracting the voltage drop caused by the diode from the voltage applied to the first conductive path when the switching unit is OFF. The first value is greater than either the first subtraction value or the second subtraction value. The control unit, when the state changes from the normal state to the failure state, turns on the switching unit and causes the voltage conversion unit to start the first conversion operation, which applies the output voltage of the first value to the third conductive path. When a predetermined condition is met while the voltage conversion unit is performing the first conversion operation, the control unit switches the switching unit to the off state, and after switching the switching unit to the off state, causes the voltage conversion unit to perform the first conversion operation, which applies the output voltage of the third value to the third conductive path. The third value is greater than the second subtraction value. Power supply control device.

5. The predetermined condition is that the voltage of the second conductive path reaches a predetermined value equal to or greater than the voltage of the first conductive path. The power supply control device according to claim 4.

6. The predetermined condition is that a predetermined amount of time has elapsed since the first conversion operation was started in the voltage conversion unit after the failure state occurred. The power supply control device according to claim 4.

7. The predetermined condition is that the current flowing through the element reaches a lower limit value or less. The power supply control device according to claim 4.

8. The predetermined condition is that the current output by the voltage conversion unit to the third conductive path after the failure state reaches a reference value or higher. The power supply control device according to claim 4.

9. The element section comprises a diode and a reverse current prevention switch. The diode and the reverse current prevention switch are arranged in series with respect to each other between the first conductive path and the second conductive path. The diode blocks the flow of current through it to the first conductive path and allows the flow of current through it to the second conductive path. The reverse current prevention switch, when in the off state, blocks the flow of current through itself to the second conductive path, and when in the on state, allows the flow of current through itself to the second conductive path. The control unit controls the reverse current prevention switch to the OFF state when in the normal state and causes the voltage conversion unit to perform the second conversion operation, and when the failure state occurs, switches the reverse current prevention switch to the ON state and causes the voltage conversion unit to start the first conversion operation. A power supply control device according to any one of claims 1 to 8.

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