Power supply control device

Abstract

This technology provides a way to suppress the leakage of output current from the voltage conversion unit to the energy storage unit through the element unit when switching from the charging state of the energy storage unit via the voltage conversion unit to the discharge state of the energy storage unit via the element unit. [Solution] The power supply control device 20 comprises a first control circuit 30 and a second control circuit 40. The first control circuit 30 controls the voltage conversion unit 25. The second control circuit 40 has a failure detection circuit 41 and a stop circuit 42. The failure detection circuit 41 outputs a cutoff signal to the element unit 24 when it determines that the power supply from the power supply unit 10 to the power line 12 is not in a failure state, and outputs an allow signal to the element unit 24 when it determines that it is in a failure state. The stop circuit 42 enters a stop control state when the failure detection circuit 41 outputs an allow signal, regardless of whether the first control circuit 30 is causing the voltage conversion unit 25 to perform a second conversion operation.

Description

Technical Field

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

Background Art

[0002] Patent Document 1 discloses a power supply control device. The power supply control device includes a first conductive path, an element unit, a second conductive path, a voltage conversion unit, a third conductive path, and a control unit. A voltage based on the output of the power storage unit is applied to the first conductive path. One end of the element unit is electrically connected to the first conductive path. The other end of the element unit is electrically connected to the second conductive path. The second conductive path forms an energization path between the element unit and the power path. The voltage conversion unit is connected in parallel to the element unit between the power storage unit and the power path. The third conductive path is electrically connected to the voltage conversion unit between the voltage conversion unit and the power path. The element unit has a reverse current prevention switch. The element unit allows current to flow to the power path side through itself when the reverse current prevention switch is in the on state, and blocks the flow of current to the power path side through itself when the reverse current prevention switch is in the off state. The voltage conversion unit performs a first conversion operation of boosting or降压 the voltage applied to the first conductive path and applying the output voltage to the third conductive path, and a second conversion operation of boosting or降压 the voltage applied to the third conductive path and applying the output voltage to the first conductive path.

[0003] In the normal state, the control unit causes the voltage conversion unit to perform the second conversion operation and turns off the reverse current prevention switch. Thereby, it is possible to prevent the current supplied from the voltage conversion unit to the first conductive path from flowing into the second conductive path and the third conductive path through the element unit. When a fault state occurs, the control unit switches the reverse current prevention switch to the on state and starts the first conversion operation of the voltage conversion unit. Thereby, the power supply to the power path through the element unit is immediately started.

Prior Art Documents

Patent Documents

[0004]

Patent Document 1

[0005] In the above configuration, assuming that the reverse current prevention switch and the voltage conversion unit are controlled by separate control circuits, a situation may occur where current is continuously supplied from the voltage conversion unit to the first conductive path when the reverse current prevention switch is switched to the ON state. In this case, there is a risk that the current supplied to the first conductive path may leak back into the second and third conductive paths via the element unit.

[0006] The present disclosure aims to provide a technology that can suppress the leakage of output current from the voltage conversion unit to the energy storage unit through the element unit when switching from the charging state of the energy storage unit by the voltage conversion unit to the discharge state of the energy storage unit via the element unit. [Means for solving the problem]

[0007] The power supply control device disclosed herein 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 from 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 first control circuit for controlling the voltage conversion unit, The system comprises a second control circuit provided separately from the first control circuit, 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 is capable of preventing current from flowing through it to the energy storage unit, and when a cutoff signal is input, it enters a cutoff state that cuts off the current flowing through it to the power line, and when an allow signal is input, it enters an allowable state that allows current to flow through it to the power line. The second control circuit includes a failure detection circuit and a stop circuit, The failure detection circuit outputs the cutoff signal to the element unit when it determines that the power supply from the power unit to the power line is not in a failure state, and outputs the allow signal to the element unit when it determines that it is in a failure state. The stop circuit enters a stop control state in which, when the failure detection circuit outputs the allowable signal, the output of the voltage conversion unit is stopped regardless of whether the first control circuit is causing the voltage conversion unit to perform the second conversion operation. [Effects of the Invention]

[0008] According to the technology disclosed herein, when switching from the charging state of the energy storage unit by the voltage conversion unit to the discharge state of the energy storage unit via the element unit, it is possible to suppress the output current from the voltage conversion unit to the energy storage unit side flowing back through the element unit. [Brief explanation of the drawing]

[0009] [Figure 1] Figure 1 is a schematic diagram showing an in-vehicle system equipped with a power supply control device according to the first embodiment. [Figure 2] Figure 2 is a diagram showing the configuration of the voltage conversion unit of the first embodiment. [Figure 3] Figure 3 is a flowchart of the processing performed by the first control circuit of the first embodiment. [Figure 4]FIG. 4 is a timing chart showing the operations of the first control circuit, the breakdown detection circuit, the stop circuit, the voltage conversion unit, and the element unit of the first embodiment before and after entering the breakdown state. [Figure 5] FIG. 5 is an explanatory diagram conceptually showing the operation of the in-vehicle system in the normal state of the first embodiment. [Figure 6] FIG. 6 is an explanatory diagram conceptually showing a state in which power is supplied from the power storage unit to the load via the element unit with the output of the voltage conversion unit stopped in the in-vehicle system of the first embodiment. [Figure 7] FIG. 7 is an explanatory diagram conceptually showing a state in which power is supplied from the power storage unit to the load via the element unit and power based on the voltage converted by the voltage conversion unit is supplied to the load in the in-vehicle system of the first embodiment. [Figure 8] FIG. 8 is a configuration diagram schematically showing an in-vehicle system including a power supply control device according to the second embodiment. [Figure 9] FIG. 9 is a configuration diagram schematically showing an in-vehicle system including a power supply control device according to the third embodiment.

Embodiments for Carrying Out the Invention

[0010] [Description of Embodiments of the Present Disclosure] First, the embodiments of the present disclosure will be listed and described.

[0011] 〔1〕A power supply control device included in an in-vehicle system including a power supply unit that supplies power, a power path that is a path through which the power from the power supply unit is transmitted, and a power storage unit different from the power supply unit, and controls power supply from the power storage unit, a first conductive path to which a voltage based on the output of the power storage unit is applied; an element unit having one end electrically connected to the first conductive path; a second conductive path that is electrically connected to the other end of the element unit and forms a current conduction path between the element unit and the power path; 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 first control circuit for controlling the voltage conversion unit, a second control circuit provided separately from the first control circuit, and the voltage conversion unit performs a first conversion operation of boosting or bucking the voltage applied to the first conductive path and applying the output voltage to the third conductive path, and a second conversion operation of boosting or bucking the voltage applied to the third conductive path and applying the output voltage to the first conductive path, the element unit can prevent current from flowing to the power storage unit side through itself, enters a blocking state in which it blocks the current flowing to the power path side through itself when a blocking signal is input, and enters an allowing state in which it allows current to flow to the power path side through itself when an allowing signal is input, the second control circuit has a fault detection circuit and a stop circuit, when the fault detection circuit determines that the power supply from the power supply unit to the power path is not in a fault state, it outputs the blocking signal toward the element unit, and when it determines that the state is a fault state, it outputs the allowing signal toward the element unit, when the fault detection circuit outputs the allowing signal, the stop circuit enters a stop control state in which it stops the output of the voltage conversion unit regardless of whether the first control circuit causes the voltage conversion unit to perform the second conversion operation, Power supply control device.

[0012] In the above power supply control device, the failure detection circuit of the second control circuit switches the element unit to an acceptable state by outputting an allow signal when it determines that a failure state has occurred. Furthermore, when the failure detection circuit outputs an allow signal, the stop circuit of the second control circuit enters a stop control state that stops the output of the voltage conversion unit, regardless of whether the first control circuit is causing the voltage conversion unit to perform the second conversion operation or not. Therefore, even if a failure state occurs while the first control circuit is causing the voltage conversion unit to perform the second conversion operation, the second control circuit switches the element unit to an acceptable state and stops the output of the voltage conversion unit. In other words, with this configuration, it is possible to suppress the leakage of output current from the voltage conversion unit to the energy storage unit side through the element unit when switching from the charging state of the energy storage unit by the voltage conversion unit to the discharge state of the energy storage unit via the element unit.

[0013] [2] When the first control circuit determines that the failure state has occurred while the voltage conversion unit is performing the second conversion operation, it releases the stop control state of the stop circuit and causes the voltage conversion unit to perform the first conversion operation. The power supply control device described in [1].

[0014] According to the above power supply control device, if the first control circuit determines that the stop circuit has entered a stop control state after the stop circuit has entered a stop control state, the stop control state of the stop circuit can be released, and the energy can be discharged from the storage unit to the load via the voltage conversion unit.

[0015] [3] The first control circuit controls the voltage conversion unit by periodic processing performed each predetermined period. The power supply control device described in [2].

[0016] In a configuration where the first control circuit controls the voltage conversion unit through periodic processing, if a failure occurs, the first control circuit waits for the start of the periodic processing and then switches the operation of the voltage conversion unit from the second conversion operation to the first conversion operation. For this reason, the timing at which the voltage conversion unit switches to the second conversion operation by the first control circuit tends to be delayed. In this regard, with the above-described power supply control device, even if the second control circuit determines that a failure has occurred and switches the element unit to an acceptable state before the first control circuit determines that a failure has occurred and switches the operation of the voltage conversion unit from the second conversion operation to the first conversion operation, the output of the voltage conversion unit is stopped by the stop circuit. In other words, even in a configuration where the first control circuit controls the voltage conversion unit through periodic processing, it is possible to suppress the output current from the voltage conversion unit to the energy storage unit side from flowing back through the element unit.

[0017] [4] The first control circuit controls the voltage conversion unit by outputting a control signal to the first signal line, and releases the stop control state of the stop circuit by outputting a release signal to a second signal line separate from the first signal line. The power supply control device described in [2] or [3].

[0018] According to the power supply control device described above, the stop control state of the stop circuit can be released using a second signal line separate from the first signal line that outputs the control signal.

[0019] [5] The first control circuit causes the voltage conversion unit to perform the first conversion operation by outputting a first signal to the signal line, and causes the voltage conversion unit to perform the second conversion operation by outputting a second signal to the signal line. The stop circuit releases the stop control state when the first signal is output from the signal line. The power supply control device described in [2] or [3].

[0020] According to the above-described power supply control device, the first control circuit outputs a first signal to the signal line, thereby releasing the stop control state of the stop circuit and causing the voltage conversion unit to perform the first conversion operation.

[0021] [Details of the embodiments of this disclosure] 1. First Embodiment 1-1. Configuration of In-Vehicle System 1 The in-vehicle system 1 shown in Figure 1 comprises a power supply unit 10, a load 11, a power line 12, a diode 13, a power storage unit 14, and a power supply control device 20.

[0022] The power supply unit 10 is a power source that supplies power to the load 11. The power supply unit 10 is composed of, for example, a battery. The power path 12 is the path through which power from the power supply unit 10 is transmitted. The power path 12 is provided between the power supply unit 10 and the load 11. The diode 13 is provided in the power path 12. The diode 13 allows current to flow from the power supply unit 10 to the load 11 through itself, and prevents current from flowing from the load 11 to the power supply unit 10 through itself. The energy storage unit 14 is a power source separate from the power supply unit 10. The energy storage unit 14 is composed of, for example, a lithium-ion battery or a lithium-ion capacitor.

[0023] The power supply control device 20 controls the power supply from the energy storage unit 14. The power supply control device 20 includes a first conductive path 21, a second conductive path 22, a third conductive path 23, an element unit 24, a voltage conversion unit 25, a voltage detection unit 26, a first control circuit 30, and a second control circuit 40.

[0024] The first conductive path 21 receives a voltage based on the output of the energy storage unit 14. The first conductive path 21 is electrically connected to the positive terminal of the energy storage unit 14. One end of the element unit 24 is electrically connected to the first conductive path 21. The other end of the element unit 24 is electrically connected to the second conductive path 22. The second conductive path 22 forms the current path between the element unit 24 and the power line 12. The second conductive path 22 is electrically connected to the power line 12 on the load 11 side of the diode 13. The voltage conversion unit 25 is connected in parallel to the element unit 24 between the energy storage unit 14 and the power line 12. The third conductive path 23 is electrically connected to the voltage conversion unit 25 between the voltage conversion unit 25 and the power line 12.

[0025] The element section 24 includes a reverse current prevention switch 24A and a diode 24B. The reverse current prevention switch 24A and the diode 24B are connected in series between the first conductive path 21 and the second conductive path 22. When the reverse current prevention switch 24A is in the off state, it blocks the current flowing through it from the first conductive path 21 to the second conductive path 22, and when it is in the on state, it allows current to flow through it from the first conductive path 21 to the second conductive path 22. The diode 24B prevents current from flowing through it from the second conductive path 22 to the first conductive path 21, and allows current to flow through it from the first conductive path 21 to the second conductive path 22.

[0026] The element 24 prevents current from flowing through it to the energy storage unit 14 by the diode 24B. When the reverse current prevention switch 24A is in the off state, the element 24 is in a blocking state that blocks the current flowing through it to the power line 12, and when the reverse current prevention switch 24A is in the on state, it is in a tolerance state that allows current to flow through it to the power line 12. The element 24 is in a blocking state when a blocking signal (specifically, an off signal) is input, and is in a tolerance state when a tolerance signal (specifically, an on signal) is input. The reverse current prevention switch 24A is composed of, for example, a MOSFET (Metal-Oxide-Semiconductor Field Effect Transistor).

[0027] The voltage conversion unit 25 performs a first conversion operation in which it increases or decreases the voltage applied to the first conductive path 21 and applies the output voltage to the third conductive path 23, and a second conversion operation in which it increases or decreases the voltage applied to the third conductive path 23 and applies the output voltage to the first conductive path 21. The voltage conversion unit 25 is configured, for example, by a DC-DC converter.

[0028] The voltage conversion unit 25 is, for example, an H-bridge type buck-boost converter as shown in Figure 2. The voltage conversion unit 25 includes switches 25A, 25B, 25C, and 25D, and an inductor 25E. Switch 25A is a high-side switch on the first conductive path 21 side. Switch 25B is a low-side switch on the first conductive path 21 side. Switch 25C is a high-side switch on the third conductive path 23 side. Switch 25D is a low-side switch on the third conductive path 23 side. One end of the inductor 25E is electrically connected to the conductive path between switches 25A and 25B. The other end of the inductor 25E is electrically connected to the conductive path between switches 25C and 25D.

[0029] The voltage detection unit 26 detects the voltage of the power line 12 and outputs a signal indicating the voltage of the power line 12. The voltage detection unit 26 detects the voltage of the power line 12 on the power supply unit 10 side of the diode 13. The voltage detection unit 26 is configured, for example, by a known voltage detection circuit.

[0030] The first control circuit 30 controls the voltage conversion unit 25. The first control circuit 30 includes an MCU 31 (Micro Controller Unit). The MCU 31 controls the voltage conversion unit 25 by periodic processing performed at predetermined intervals. In this embodiment, the predetermined period is the time between the start and end times of the periodic processing, but it may also be the time from the end of one periodic processing to the start of the next periodic processing. When the power supply from the power supply unit 10 to the power line 12 is lost, the MCU 31 causes the voltage conversion unit 25 to perform a first conversion operation and supply power from the energy storage unit 14 to the load 11.

[0031] A power failure state is an abnormal state in which the power supply from the power supply unit 10 to the power line 12 has decreased to a predetermined standard or has stopped. In this embodiment, a power failure state is a state in which the voltage of the power line 12 (i.e., the value detected by the voltage detection unit 26) has decreased to a threshold Vth or lower. The threshold Vth is a value that is less than the output voltage of the power supply unit 10 when fully charged and is 0V or greater.

[0032] The MCU31 is electrically connected to a first signal line 51 and a second signal line 52 that is different from the first signal line 51. The MCU31 controls the voltage conversion unit 25 by outputting a control signal to the first signal line 51. The MCU31 outputs one of a plurality of signals, including a first signal, a second signal, and a third signal, as a control signal. The MCU31 causes the voltage conversion unit 25 to perform a first conversion operation by outputting the first signal. The MCU31 causes the voltage conversion unit 25 to perform a second conversion operation by outputting the second signal. The MCU31 stops the output of the voltage conversion unit 25 by outputting the third signal. The MCU31 stops the output of the voltage conversion unit 25 by controlling at least one of the switches 25A, 25B, 25C, 25D that constitute the voltage conversion unit 25 (for example, switch 25A) to the off state.

[0033] The second control circuit 40 is provided separately from the first control circuit 30. The second control circuit 40 is composed of hardware circuits. The second control circuit 40 includes a failure detection circuit 41 and a stop circuit 42.

[0034] The failure detection circuit 41 outputs a cutoff signal (specifically, an off signal) to the element unit 24 when it determines that there is no failure, and outputs an allow signal (specifically, an on signal) to the element unit 24 when it determines that there is a failure. The failure detection circuit 41 is composed of, for example, a comparator. The failure detection circuit 41 receives a signal output from the voltage detection unit 26 (i.e., a signal indicating the voltage of the power line 12) and a threshold Vth as input. The failure detection circuit 41 outputs an off signal when the voltage of the power line 12 is greater than the threshold Vth. The failure detection circuit 41 outputs an on signal when the voltage of the power line 12 becomes less than or equal to the threshold Vth. A third signal line 53 is provided between the failure detection circuit 41 and the element unit 24. The failure detection circuit 41 selectively outputs a cutoff signal and an allow signal to the third signal line 53.

[0035] The stop circuit 42 enters a stop control state where, when the failure detection circuit 41 outputs an allowable signal, it stops the output of the voltage conversion unit 25, regardless of whether the first control circuit 30 is causing the voltage conversion unit 25 to perform a second conversion operation. When the failure detection circuit 41 outputs a cutoff signal, the stop circuit 42 enters a released state, releasing the stop control state.

[0036] The stop circuit 42 is provided between the first control circuit 30 (specifically, the MCU 31) and the voltage conversion unit 25. The stop circuit 42 receives the signal output from the failure detection circuit 41 to the third signal line 53 and the signal output from the MCU 31 to the first signal line 51. The signal output from the failure detection circuit 41 is input to the stop circuit 42 via the fourth signal line 54, which is branched from the third signal line 53.

[0037] The stop circuit 42 has an inverter 43. The inverter 43 outputs an off signal when an on signal is input from the failure detection circuit 41 via the fourth signal line 54, and outputs an on signal when an off signal is input from the failure detection circuit 41 via the fourth signal line 54.

[0038] The stop circuit 42 has a switching unit 44. The switching unit 44 has a first terminal 45, a second terminal 46, and a third terminal 47. The first terminal 45 is electrically connected to the first signal line 51. The second terminal 46 is electrically connected to the output terminal of the inverter 43. The third terminal 47 is electrically connected to the output line 59 provided between the third terminal 47 and the voltage conversion unit 25.

[0039] The switching unit 44 switches between a first connection state in which the third terminal 47 is connected to the first terminal 45, and a second connection state in which the third terminal 47 is connected to the second terminal 46. When the failure detection circuit 41 is outputting an off signal, no switching signal (specifically, an on signal) is input to the switching unit 44 via the switching line 55, and the switching unit 44 is in the first connection state. At this time, the control signal output from the MCU 31 is output to the voltage conversion unit 25 via the switching unit 44, and the voltage conversion unit 25 is controlled based on the control signal. In other words, the stop circuit 42 is in the released state.

[0040] When the failure detection circuit 41 outputs an ON signal, a switching signal is input to the switching unit 44 via the switching line 55, and the switching unit 44 enters the second connection state. At this time, an OFF signal output from the inverter 43 is input to the second terminal 46, and an OFF signal is output from the switching unit 44 to the voltage conversion unit 25 via the output line 59. As a result, the output of the voltage conversion unit 25 stops. In other words, the stop circuit 42 enters a stop control state.

[0041] Even when a switching signal is input to the switching unit 44 via the switching line 55, if a release signal is input to the switching unit 44 from the MCU 31 via the second signal line 52, it switches to the first connection state. As a result, the stop circuit 42 enters the release state.

[0042] The MCU31 causes the voltage conversion unit 25 to perform a second conversion operation when the charging conditions are met in a normal state that is not a failure state. For example, the charging conditions are met during the period from when the voltage of the power line 12 falls below the charging start voltage to when it rises above the charging end voltage. The charging start voltage is a value that is lower than the output voltage of the power supply unit 10 when fully charged and greater than the threshold voltage Vth. The charging end voltage is a value that is less than or equal to the output voltage of the power supply unit 10 when fully charged and greater than the charging start voltage.

[0043] If the MCU31 determines that a failure has occurred while the voltage conversion unit 25 is performing the second conversion operation, it outputs a release signal to the second signal line 52, thereby releasing the stop control state of the stop circuit 42. Then, the MCU31 causes the voltage conversion unit 25 to perform the first conversion operation.

[0044] The MCU31 performs the process shown in Figure 3, for example, by repeatedly performing periodic processing. In the process shown in Figure 3, the MCU31 determines in step S11 whether or not the charging conditions are met. If the MCU31 determines that the charging conditions are met (step S11: Yes), in step S12, it outputs a second signal to the first signal line 51, causing the voltage conversion unit 25 to perform a second conversion operation. If the MCU31 determines that the charging conditions are not met (step S11: No), in step S13, it outputs a third signal to the first signal line 51, stopping the output of the voltage conversion unit 25.

[0045] After step S12 or S13, in step S14, the MCU31 determines whether or not it has entered a failure state. If the MCU31 determines that it has not entered a failure state (step S14: No), it returns to the process in step S11. In other words, in the normal state, the MCU31 causes the voltage conversion unit 25 to perform a second conversion operation when the charging conditions are met, and stops the output of the voltage conversion unit 25 when the charging conditions are not met.

[0046] If the MCU 31 determines that a failure has occurred (step S14: Yes), in step S15, it outputs a release signal to the second signal line 52 to release the stop control state of the stop circuit 42. Also in step S15, the MCU 31 outputs a first signal to the first signal line 51 to cause the voltage conversion unit 25 to perform the first conversion operation.

[0047] Figure 4 shows a timing chart illustrating the operation of the first control circuit 30, failure detection circuit 41, stop circuit 42, voltage conversion unit 25, and element unit 24 before and after the failure state. Timings t1 to t2 represent the normal state. In the normal state, the first control circuit 30 outputs the second signal, the voltage conversion unit 25 performs the second conversion operation, the failure detection circuit 41 outputs an off signal, the stop circuit 42 is in the released state, and the element unit 24 is controlled to the cutoff state. In this state, as shown in Figure 5, power is supplied from the power supply unit 10 to the load 11, and the power supplied from the power supply unit 10 is charged to the energy storage unit 14 via the voltage conversion unit 25.

[0048] When a failure occurs at timing t2, the output signal of the failure detection circuit 41 switches to an ON signal. As a result, the element unit 24 switches to an allowable state, the stop circuit 42 enters a stop control state, and the output of the voltage conversion unit 25 stops. Thus, as shown in Figure 6, power is supplied from the energy storage unit 14 to the load 11 via the element unit 24 while the output of the voltage conversion unit 25 is stopped.

[0049] Subsequently, the first control circuit 30, in the periodic processing immediately following the failure, determines that a failure has occurred, switches the stop circuit 42 to the release state, and causes the voltage conversion unit 25 to perform the first conversion operation (timing t3). As a result, as shown in Figure 7, power is supplied from the energy storage unit 14 to the load 11 via the element unit 24, and power based on the voltage converted by the voltage conversion unit 25 is also supplied to the load 11.

[0050] 1-2. Effects of the First Embodiment In the power supply control device 20, the failure detection circuit 41 of the second control circuit 40 switches the element unit 24 to an acceptable state by outputting an allow signal when it determines that a failure state has occurred. Furthermore, when the failure detection circuit 41 outputs an allow signal, the stop circuit 42 of the second control circuit 40 enters a stop control state that stops the output of the voltage conversion unit 25, regardless of whether the first control circuit 30 is causing the voltage conversion unit 25 to perform the second conversion operation or not. Therefore, even if a failure state occurs while the first control circuit 30 is causing the voltage conversion unit 25 to perform the second conversion operation, the second control circuit 40 switches the element unit 24 to an acceptable state and stops the output of the voltage conversion unit 25. In other words, with this configuration, it is possible to suppress the output current from the voltage conversion unit 25 to the energy storage unit 14 side from flowing back through the element unit 24 when switching from the charging state of the energy storage unit 14 by the voltage conversion unit 25 to the discharge state of the energy storage unit 14 via the element unit 24.

[0051] According to the power supply control device 20, if it determines that the first control circuit 30 has failed after the stop circuit 42 has entered a stop control state, it can release the stop control state of the stop circuit 42 and discharge from the energy storage unit 14 to the load 11 via the voltage conversion unit 25.

[0052] In a configuration where the first control circuit 30 controls the voltage conversion unit 25 by periodic processing, if a failure occurs, the first control circuit 30 waits for the start of periodic processing and then switches the operation of the voltage conversion unit 25 from the second conversion operation to the first conversion operation. For this reason, the timing at which the operation of the voltage conversion unit 25 is switched to the second conversion operation by the first control circuit 30 tends to be delayed. In this regard, with the power supply control device 20, even if the second control circuit 40 determines that a failure has occurred and switches the element unit 24 to an acceptable state before the first control circuit 30 determines that a failure has occurred and switches the operation of the voltage conversion unit 25 from the second conversion operation to the first conversion operation, the output of the voltage conversion unit 25 is stopped by the stop circuit 42. In other words, even in a configuration where the first control circuit 30 controls the voltage conversion unit 25 by periodic processing, it is possible to suppress the output current from the voltage conversion unit 25 to the energy storage unit 14 side from flowing back through the element unit 24.

[0053] According to the power supply control device 20, the stop control state of the stop circuit 42 can be released using a second signal line 52, which is separate from the first signal line 51 that outputs the control signal.

[0054] 2. Second Embodiment The second embodiment differs from the first embodiment only in the configuration for releasing the stop control state of the stop circuit. In the second embodiment, the same reference numerals are used for components that are the same as in the first embodiment, and detailed descriptions are omitted.

[0055] The in-vehicle system 201 of the second embodiment shown in Figure 8 includes a power supply control device 220 instead of the power supply control device 20 described in the first embodiment. The power supply control device 220 is provided with a branch line 56 that branches off from the first signal line 51. The control signal that the MCU 31 outputs to the first signal line 51 is input to the switching unit 44 of the stop circuit 42 via the branch line 56. When the stop circuit 42 is in a stop control state, if the MCU 31 outputs a first signal to the first signal line 51, the first signal is input to the switching unit 44 via the branch line 56. As a result, the stop circuit 42 switches to the release state.

[0056] According to the power supply control device 220, the first control circuit 30 outputs a first signal to the first signal line 51, thereby releasing the stop control state of the stop circuit 42 and causing the voltage conversion unit 25 to perform the first conversion operation.

[0057] 3. Third Embodiment The third embodiment differs from the first embodiment only in the configuration of the element section. In the third embodiment, the same reference numerals are used for components that are the same as in the first embodiment, and detailed descriptions are omitted.

[0058] The in-vehicle system 301 of the third embodiment shown in Figure 9 includes a power supply control device 320 instead of the power supply control device 20 described in the first embodiment. The power supply control device 320 includes an element unit 324 instead of the element unit 24 described in the first embodiment. The element unit 324 has a MOSFET 324A. The MOSFET 324A is oriented in the opposite direction to the reverse current prevention switch 24A described in the first embodiment. The source of the MOSFET 324A is electrically connected to the first conductive path 21. The drain of the MOSFET 324A is electrically connected to the second conductive path 22.

[0059] MOSFET324A has a resistance value adjusted so that when it is in the off state and the voltage conversion unit 25 is performing the second conversion operation, no current flows from the first conductive path 21 to the second conductive path 22 via its body diode 324B. Therefore, when MOSFET324A is in the off state, element 324 is in a blocking state that blocks the current flowing to the power path 12 via itself, and when MOSFET324A is in the on state, it is in a tolerance state that allows current to flow to the power path 12 via itself.

[0060] <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.

[0061] The first control circuit may be configured by a hardware circuit.

[0062] The element in the third embodiment described above may have a resistor connected in series with the MOSFET in addition to the MOSFET. With this configuration, by adjusting the resistance value of the resistor, the element can be configured so that no current flows from the first conductive path to the second conductive path through the element when the MOSFET is in the off state and the voltage conversion unit is performing the second conversion operation.

[0063] 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 equivalent to the claims are intended to be included. [Explanation of Symbols]

[0064] 1…In-vehicle systems 10...Power supply section 11…Load 12…Power line 13…Diode 14…Energy storage unit 20... Power supply control device 21…First conductive path 22...Second conductive circuit 23…Third conductive circuit 24... Element section 24A…Backflow prevention switch 24B…diode 25...Voltage conversion section 25A…Switch 25B... Switch 25C…Switch 25D…Switch 25E...Inductor 26...Voltage detection unit 30...First control circuit 31…MCU 40...Second control circuit 41...Loss detection circuit 42…Stop circuit 43…Inverter 44…Switching section 45...1st terminal 46...2nd terminal 47…3rd terminal 51...First signal line 52... Second signal line 53... Third signal line 54…Fourth signal line 55…Switching line 56... Branch line 59…Output line 201... In-vehicle systems 220... Power supply control device 301... In-vehicle systems 320... Power supply control device 324... Element part 324A… MOSFET 324B...Body diode Vth... threshold

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 from 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 first control circuit for controlling the voltage conversion unit, The system comprises a second control circuit provided separately from the first control circuit, 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 is capable of preventing current from flowing through it to the energy storage unit, and when a cutoff signal is input, it enters a cutoff state that cuts off the current flowing through it to the power line, and when an allow signal is input, it enters an allowable state that allows current to flow through it to the power line. The second control circuit includes a failure detection circuit and a stop circuit, The failure detection circuit outputs the cutoff signal to the element unit when it determines that the power supply from the power unit to the power line is not in a failure state, and outputs the allow signal to the element unit when it determines that it is in a failure state. The stop circuit enters a stop control state in which, when the failure detection circuit outputs the allowable signal, the output of the voltage conversion unit is stopped regardless of whether the first control circuit is causing the voltage conversion unit to perform the second conversion operation. Power supply control device.

2. If the first control circuit determines that the failure state has occurred while the voltage conversion unit is performing the second conversion operation, it releases the stop control state of the stop circuit and causes the voltage conversion unit to perform the first conversion operation. The power supply control device according to claim 1.

3. The first control circuit controls the voltage conversion unit by periodic processing performed each predetermined period. The power supply control device according to claim 2.

4. The first control circuit controls the voltage conversion unit by outputting a control signal to the first signal line, and releases the stop control state of the stop circuit by outputting a release signal to a second signal line separate from the first signal line. The power supply control device according to claim 2 or claim 3.

5. The first control circuit causes the voltage conversion unit to perform the first conversion operation by outputting a first signal to the signal line, and causes the voltage conversion unit to perform the second conversion operation by outputting a second signal to the signal line. The stop circuit releases the stop control state when the first signal is output from the signal line. The power supply control device according to claim 2 or claim 3.

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