Power supply unit and motor unit

Abstract

To provide a power supply device capable of suppressing variation of supply voltage to a load device.SOLUTION: A power supply device includes: a power storage device; a bidirectional step up / down converter having a charging function that, upon a voltage of the power storage device, being decreasing, reaching a first threshold value, initiates charging the power storage device according to input power from a vehicle power system, and upon the voltage of the power storage device, being increasing, reaching a second threshold value higher than the first threshold value, stops charging the power storage device, and the bidirectional step up / down converter also having a boosting function for boosting the voltage of the power storage device; a control circuit for causing a boosting circuit to perform boost operation so that a boost voltage higher than the voltage of the power storage device is supplied to a load device at a constant voltage; and a power supply path with one end thereof being connected to the power system and the other end thereof being connected to an output node side of the boost voltage.SELECTED DRAWING: Figure 1

Description

Technical Field

[0001] The present disclosure relates to a power supply device and an electric device.

Background Art

[0002] In a latch mechanism of a door of a vehicle such as an automobile, an electric latch system that performs a latch release operation by an electric actuator has begun to be adopted. The voltage supplied to the electric actuator is normally supplied from the main power source of the vehicle. However, it is required that the vehicle door can be unlocked even in an emergency such as an accident. Therefore, the electric latch system often includes a backup power source so that the electric actuator can continue to operate for a certain period of time even when the power supply from the main power source to the electric actuator is cut off in an emergency such as an accident.

Prior Art Documents

Patent Documents

[0003]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0004] However, when the voltage of the main power source or the backup power source fluctuates, the voltage supplied to a load device such as an electric actuator may fluctuate.

[0005] The present disclosure provides a power supply device capable of suppressing fluctuations in the voltage supplied to a load device, and an electric device including the power supply device.

Means for Solving the Problems

[0006] In one aspect of the present disclosure, a power storage device, and A charging circuit that, when the voltage of the energy storage device drops to a first threshold, starts charging the energy storage device based on the input power from the vehicle's power system, and stops charging the energy storage device when the voltage of the energy storage device rises to a second threshold higher than the first threshold, A boost circuit for boosting the voltage of the aforementioned energy storage device, A power supply device is provided, and an electric motor device equipped with the power supply device is provided, which includes a control circuit that causes the boost circuit to operate in a boosting operation so that a boost voltage higher than the voltage of the energy storage device is supplied to the load device at a constant voltage. [Effects of the Invention]

[0007] According to one aspect of this disclosure, fluctuations in the voltage supplied to the load device can be suppressed. [Brief explanation of the drawing]

[0008] [Figure 1] This figure shows an example configuration of an electric motor equipped with a power supply device according to the first embodiment. [Figure 2] This is a timing chart showing an example of the operation of the power supply device according to the first embodiment. [Figure 3] This figure shows an example configuration of an electric motor equipped with a power supply device according to the second embodiment. [Figure 4] This is a timing chart showing an example of the operation of the power supply device according to the second embodiment. [Figure 5] This figure shows an example configuration of an electric motor equipped with a power supply device according to the third embodiment. [Figure 6] This is a timing chart showing an example of the operation of the power supply unit according to the third embodiment. [Figure 7] This figure shows an example configuration of an electric motor equipped with a power supply according to the fourth embodiment. [Figure 8] This is a timing chart showing an example of the operation of the power supply unit according to the fourth embodiment. [Figure 9] This table summarizes examples of operation for each embodiment. [Modes for carrying out the invention]

[0009] The embodiments will be described below.

[0010] Figure 1 shows an example of the configuration of an electric motor equipped with a power supply device according to the first embodiment. The electric motor 101 shown in Figure 1 is mounted on a vehicle such as an automobile and operates a load device 200 based on input power from the vehicle's power system 90. The power system 90 includes, for example, a main power supply mounted on the vehicle (for example, a 12-volt DC battery) and a power harness connecting the main power supply and the power terminals of the electric motor 101. The main power supply may also be a converter.

[0011] The electric motor 101 includes a load device 200 and a power supply device 1.

[0012] The load device 200 is a device that controls the operation of equipment operated by the user (for example, an opening / closing mechanism such as a door), and operates using DC power supplied from the power supply device 1. The load device 200 comprises a drive circuit 220 and a load 210. The drive circuit 220 is a driver that operates using DC power supplied from the power supply device 1 and drives the load 210. The load 210 is a device capable of controlling the operation of equipment operated by the user, for example, a motor. When the load 210 is a motor, a specific example of the drive circuit 220 is an H-bridge circuit.

[0013] The electric device 101 is, for example, an electric latch device that uses an electric actuator to release the latch, which is a mechanical locking mechanism for opening and closing parts such as vehicle doors. Opening and closing parts such as vehicle doors are examples of equipment operated by the user, and are opened and closed by user operation such as a door handle, remote control, contact sensor, non-contact sensor, etc. If the electric device 101 is an electric latch device, the load 210 is, for example, the motor of the electric actuator that performs the latch release operation.

[0014] Note that the electric device 101 is not limited to an electric latch device. The electric device 101 may be an electric brake device that performs a braking operation of a brake mechanism of a vehicle by an electric actuator. The brake mechanism is an example of equipment operated by a user and is actuated by a user's operation such as a brake pedal. The electric device 101 may also be an electric retractor device that performs a winding operation of a vehicle seat belt by an electric motor. The seat belt is an example of equipment operated by a user and is taken in and out by a user's operation.

[0015] The power supply device 1 generates power to be supplied to the load device 200 based on the power supplied from the power system 90. The power supply device 1 includes a power storage device 10 that stores the power supplied from the power system 90 so that power can be continuously supplied to the load device 200 for a certain period even when the power supply from the power system 90 is interrupted.

[0016] The power supply device 1 includes a power storage device 10, an equalization circuit 40, a power supply path 80, a bidirectional buck-boost converter 60, a regulator 51, a diode 52, and a control circuit 50.

[0017] The power storage device 10 is a device that stores electricity. The power storage device 10 has at least one cell (in this example, two cells 11 and 12 connected in series). The cells 11 and 12 are elements that store electricity and are, for example, electric double layer capacitors (so-called supercapacitors). The power storage device 10 may also be a secondary battery such as a nickel-metal hydride battery.

[0018] The equalization circuit 40 performs an equalization process (a process of making the voltages applied to the cells 11 and 12 equal) of the power storage device 10. In this example, the equalization circuit 40 has a plurality of resistors 41 and 42 connected in series. The resistors 41 and 42 have the same resistance value as each other. The resistor 41 is an element connected in parallel to the cell 11, and the resistor 42 is an element connected in parallel to the cell 12.

[0019] The power supply path 80 is a wiring configuration in which one end is connected to the power system 90 and the other end is connected to the output node 65 side of the bidirectional step-up / step-up converter 60. In this example, a reverse current prevention circuit 81, an overcurrent prevention circuit 82, and a resistor 83 are inserted in series in the power supply path 80. The reverse current prevention circuit 81 prevents current from flowing back from the output node 65 to the power system 90 due to reverse connection of the main power supply, etc. The overcurrent prevention circuit 82 prevents overcurrent from the power system 90 to the output node 65.

[0020] The bidirectional buck-boost converter 60 has a boost function that boosts the voltage Vc of the energy storage device 10 and outputs a voltage Vb higher than Vc to the output node 65, and a buck function that steps down the voltage Vb of the output node 65 and outputs a voltage Vc lower than Vb to the energy storage device 10. The boost function causes discharge from the energy storage device 10, and a voltage Vb higher than the voltage Vc of the energy storage device 10 (also called the "boost voltage") can be supplied as the power supply voltage to the load device 200. The buck function allows the energy storage device 10 to be charged at a voltage lower than the voltage Vb of the output node 65. In other words, the bidirectional buck-boost converter 60 is a bidirectional DC / DC converter that integrates a boost circuit that boosts the voltage Vc of the energy storage device 10 and a charging circuit that charges the energy storage device 10. The bidirectional buck-boost converter 60 may have a known circuit configuration, and in this example, it has an inductor 61, switching elements 62, 63 and a smoothing capacitor 64. The switching elements 62 and 63 are, for example, semiconductor elements, and a specific example is a MOSFET (Metal Oxide Semiconductor Field Effect Transistor) with a parasitic diode.

[0021] The regulator 51 is a circuit that generates the power supply voltage Vd of the control circuit 50 based on the power supplied from either the power grid 90 or the energy storage device 10. As a result, even if the power supply from the power grid 90 is interrupted, the regulator 51 can generate the power supply voltage Vd of the control circuit 50 based on the power supplied from the energy storage device 10. Furthermore, by providing the regulator 51, the power supply voltage Vd of the control circuit 50 can be kept constant even if the voltage Va input from the power grid 90 or the voltage Vc of the energy storage device 10 fluctuates.

[0022] The regulator 51 generates the power supply voltage Vd for the control circuit 50 based on, for example, the higher of the voltage Va input from the power system 90 and the voltage Vc of the energy storage device 10 (more precisely, considering the forward voltage of the diode 52). The regulator 51 is, for example, a low-dropout regulator.

[0023] Diode 52 is an element in which the anode is connected to the output side of the energy storage device 10 and the cathode is connected to the input side of the regulator 51. Diode 52 prevents reverse current flow from the power supply path 80 to the energy storage device 10.

[0024] The control circuit 50 boosts the bidirectional buck-boost converter 60 so that a constant voltage Vb, higher than the voltage Vc of the energy storage device 10, is supplied to the load device 200. The control circuit 50 can supply a constant voltage Vb to the drive circuit 220 of the load device 200 by performing feedback control to switch the switching element 62 so that the voltage Vb at the output node 65 is maintained at a predetermined constant voltage.

[0025] The control circuit 50 operates the bidirectional buck-boost converter 60 to charge the energy storage device 10 based on the power input from the output node 65 via the power supply path 80. The control circuit 50 operates the bidirectional buck-boost converter 60 to charge by switching the switching element 63. For example, when the voltage Vc of the energy storage device 10 drops to a first threshold Vth1, the control circuit 50 operates the bidirectional buck-boost converter 60 to charge, and when the voltage Vc rises to a second threshold Vth2, it stops the charging operation of the bidirectional buck-boost converter 60. As a result, even if the voltage Va input from the power system 90 fluctuates due to load fluctuations such as engine starting, the fluctuation range of the voltage Vc of the energy storage device 10 can be suppressed to be between the first threshold Vth1 and the second threshold Vth2.

[0026] The second threshold Vth2 is set to a value greater than the first threshold Vth1, and less than the normal voltage Va from power system 90. For example, if the normal voltage Va is 9-16 volts, the second threshold Vth2 is set to approximately 5 volts, and the first threshold Vth1 is set to approximately 3 volts.

[0027] The control circuit 50 acquires an operation detection signal S that indicates the user's operation status of the equipment. If the electric device 101 is an electric latching device, the operation detection signal S indicates whether or not the user has performed an operation using a door handle, remote control, contact sensor, non-contact sensor, etc.

[0028] The control circuit 50 is, for example, a microcomputer having memory and a processor such as a CPU (Central Processing Unit). The functions of the control circuit 50 are realized by the processor operating according to a program stored in memory. The functions of the control circuit 50 may also be realized by an FPGA (Field Programmable Gate Array) or an ASIC (Application Specific Integrated Circuit).

[0029] Figure 2 is a timing chart showing an example of operation of the power supply device according to the first embodiment. An abnormal state refers to a condition in which the power supply from the power system 90 to the electric motor device 101 is cut off due to a failure in the power system 90, or a condition in which an emergency signal such as vehicle collision detection is issued in the event of an accident or other emergency. In Figure 2, the abnormal state corresponds to the high-level period (the same applies to other timing charts described later). Timings a, b, c, d, and e are normal. Timings f, g, h, i, j, k, l, and m are abnormal.

[0030] In the first embodiment, the control circuit 50 operates the bidirectional buck-boost converter 60 to boost voltage when equipment such as a door is being operated. On the other hand, the control circuit 50 stops the boosting operation of the bidirectional buck-boost converter 60 when equipment such as a door is not being operated. For example, the control circuit 50 operates the bidirectional buck-boost converter 60 to boost voltage when an operation detection signal S indicating that equipment such as a door is being operated is input, regardless of whether it is normal or abnormal (without monitoring an emergency signal).

[0031] The control circuit 50 may start the boost operation of the bidirectional buck-boost converter 60 when it detects the operation of the equipment by the operation detection signal S. On the other hand, the control circuit 50 may stop the boost operation of the bidirectional buck-boost converter 60 when a predetermined stop condition is met after the operation of the equipment is detected. The predetermined stop condition may be when the operation of the equipment has stopped or is deemed to have stopped, or when a predetermined time has elapsed since the operation of the equipment was detected. The predetermined stop condition may also be when the operation of the equipment is no longer detected by the operation detection signal S.

[0032] In the first embodiment, the control circuit 50 switches whether or not to perform a step-down operation (charging operation) of the bidirectional step-up converter 60 depending on the magnitude of the voltage Vc of the energy storage device 10 while the engine is ON (operating), regardless of whether or not the equipment is being operated. When the voltage Vc of the energy storage device 10 drops to a first threshold Vth1, the control circuit 50 starts the charging operation of the bidirectional step-up converter 60, and when the voltage Vc rises to a second threshold Vth2, it stops the charging operation of the bidirectional step-up converter 60.

[0033] For example, if the voltage Vc of the energy storage device 10 drops to a first threshold Vth1 due to continuous operation of the equipment, the control circuit 50 may forcibly start the charging operation of the bidirectional step-up / step-up converter 60, even if the operation of the equipment has been detected by the operation detection signal S.

[0034] At timing b, when power is input from the power system 90, such as when the vehicle engine starts, the power supply unit 1 starts up. If the voltage Vc is lower than the first threshold Vth1, the control circuit 50 operates the bidirectional buck-boost converter 60 as a buck converter (charging circuit) and charges the energy storage device 10 until the voltage Vc rises to the second threshold Vth2. Due to the charging operation, the voltage Vc of the energy storage device 10 gradually increases.

[0035] At timings c and d, when the operation of equipment such as a door is detected by the operation detection signal S, the control circuit 50 operates the bidirectional buck-boost converter 60 as a boost converter (boost circuit) powered by the energy storage device 10. The control circuit 50 boosts the bidirectional buck-boost converter 60 so that a voltage Vb higher than the voltage Vc of the energy storage device 10 is supplied to the load device 200 at a constant voltage, thereby suppressing fluctuations in the voltage Vb supplied to the load device 200. Due to the boost operation, the voltage Vc of the energy storage device 10 gradually decreases.

[0036] At timing e, when the operation of equipment such as a door is detected and a predetermined stop condition is met, the control circuit 50 stops the boost operation of the bidirectional buck-boost converter 60. When the voltage Vc drops to the first threshold Vth, the control circuit 50 operates the bidirectional buck-boost converter 60 as a buck converter so that the energy storage device 10 is charged. When the voltage Vc rises to the second threshold Vth2, the control circuit 50 stops the charging operation of the bidirectional buck-boost converter 60.

[0037] Timings f, g, h, and i indicate abnormal conditions. During this period, the voltage Vc is higher than the first threshold Vth1 (and has not decreased to the first threshold Vth1), and operation of equipment such as doors is not detected by the operation detection signal S. Therefore, the control circuit 50 stops the charging and boosting operations of the bidirectional step-up / step-up converter 60.

[0038] At timings i and k, when the operation of equipment such as a door is detected by the operation detection signal S, the control circuit 50 operates the bidirectional buck-boost converter 60 as a boost converter (boost circuit) powered by the energy storage device 10. The control circuit 50 boosts the bidirectional buck-boost converter 60 so that a voltage Vb higher than the voltage Vc of the energy storage device 10 is supplied to the load device 200 at a constant voltage, thereby suppressing fluctuations in the voltage Vb supplied to the load device 200. Due to the boost operation, the voltage Vc of the energy storage device 10 gradually decreases.

[0039] At timing l, when the operation of equipment such as a door is detected and a predetermined stop condition is met, the control circuit 50 stops the boost operation of the bidirectional buck-boost converter 60. The control circuit 50 maintains the stopped boost operation state without operating the bidirectional buck-boost converter 60 as a buck converter, unless the voltage Vc has fallen to the first threshold Vth. As a result, the voltage Vc of the energy storage device 10 is kept constant.

[0040] Thus, in the first embodiment, regardless of whether there is a failure or emergency in the power system 90, the control circuit 50 operates the bidirectional buck-boost converter 60 to boost the voltage so that a boost voltage higher than the voltage Vc of the energy storage device 10 is supplied to the load device 200 at a constant voltage. As a result, even if the voltage of the power system 90 or the energy storage device 10 fluctuates, a constant voltage can be supplied to the load device 200.

[0041] Figure 3 shows an example of the configuration of an electric motor equipped with a power supply device according to the second embodiment. In the second embodiment, the description of the configuration, operation, and effects similar to those of the first embodiment will be omitted or simplified by referring to the above description.

[0042] The electric motor device 102 shown in Figure 3 comprises a power supply device 2 and a load device 200. The power supply device 2 differs from the first embodiment in that it comprises diodes 71, 72, a charging circuit 20, and a boost circuit 30. In other words, the power supply device 2 according to the second embodiment is not a buck-boost converter in which the charging circuit (buck circuit) and boost circuit are integrated, but rather comprises the charging circuit (buck circuit) and boost circuit separately.

[0043] Note that the components shown in Figure 1 (reverse current prevention circuit 81, overcurrent prevention circuit 82, resistor 83, equalization circuit 40, regulator 51, diode 52) are not shown in Figure 3. However, the power supply device 2 according to the second embodiment may include some or all of these components (the same applies to other embodiments described later).

[0044] In Figure 3, diode 71 is inserted into the power supply path 80 to prevent reverse current flow from output node 65 to power system 90. Diode 72 prevents reverse current flow from output node 65 to boost circuit 30. Diodes 71 and 72 constitute a diode-OR circuit.

[0045] Furthermore, since diode 33 is present in the boost circuit 30, diode 72 is not necessary. The presence of diode 72 protects the smoothing capacitor 34 in the boost circuit 30 from overvoltage. Also, even without diode 72, when the power input from the power system 90 is interrupted, the power supply path to the load device 200 automatically switches from via the power supply path 80 to via the boost circuit 30.

[0046] The charging circuit 20 has a step-down function (charging function) that steps down the voltage Va input from the power system 90 and charges the energy storage device 10 with a voltage Vc lower than the voltage Va. When the voltage Vc of the energy storage device 10 drops to a first threshold Vth1, the charging circuit 20 starts charging the energy storage device 10 based on the input power from the power system 90. On the other hand, when the voltage Vc of the energy storage device 10 rises to a second threshold Vth2 which is higher than the first threshold Vth1, the charging circuit 20 stops charging the energy storage device 10. The charging circuit 20 may monitor the voltage Vc itself and perform charging operations independently without receiving commands from the control circuit 50, or it may perform charging operations in accordance with commands from the control circuit 50. The charging circuit 20 may have a known circuit configuration.

[0047] The boost circuit 30 has a boosting function that increases the voltage Vc of the energy storage device 10 and outputs a voltage Vb higher than voltage Vc to the output node 65. The boost circuit 30 may have a known circuit configuration, and in this example it has an inductor 31, a switching element 32, a diode 33, and a smoothing capacitor 34. The switching element 32 is, for example, a semiconductor element, and a specific example is a MOSFET with a parasitic diode.

[0048] The control circuit 50 keeps the boost circuit 30 running at all times so that the voltage Vb is lower than the voltage Va of the power supply path 80. This allows power to be supplied from the power system 90 to the load device 200 via the power supply path 80 under normal conditions.

[0049] In the second embodiment, the control circuit 50 acquires (monitors) an emergency signal E, such as vehicle collision detection. The control circuit 50 may also acquire (monitors) an operation detection signal S, which represents the user's operation status of the equipment.

[0050] Figure 4 is a timing chart showing an example of the operation of the power supply unit according to the second embodiment.

[0051] In the second embodiment, the control circuit 50 keeps the boost circuit 30 running at all times so that the voltage Vb is lower than the voltage Va of the power supply path 80. This allows power to be supplied from the power system 90 to the load device 200 via the power supply path 80 under normal conditions. Therefore, the operating power generated by the load device 200 when the equipment is operated under normal conditions (timings c, d) is covered by the power supplied from the power system 90 via the power supply path 80. The voltage Vc of the energy storage device 10 is maintained.

[0052] In the second embodiment, when the control circuit 50 detects a vehicle abnormality by an emergency signal E at timing f, it starts the boost operation of the boost circuit 30 so that current is supplied from the boost circuit 30 to the load device 200. When the control circuit 50 detects a vehicle abnormality by an emergency signal E, it starts the boost circuit 30 in intermittent operation or PFM operation, and when the operation of an equipment is detected by an operation detection signal S at timing j, it switches the boost circuit 30 to PWM operation. The control circuit 50 may switch the operation of the boost circuit 30 from PWM operation to intermittent operation or PFM operation when a predetermined stop condition is met at timing l after the operation of an equipment such as a door is detected. The control circuit 50 may continue the operation of the boost circuit 30 in intermittent operation or PFM operation even after timing m when the engine is turned off.

[0053] Intermittent operation or PFM (Pulse Frequency Modulation) operation can improve boost efficiency at light loads by reducing the number of switching cycles per unit time. PWM (Pulse Wide Modulation) operation can improve boost efficiency at medium to high loads. Therefore, by starting the boost circuit 30 in intermittent or PFM operation, power consumption from the time an abnormality is detected until the operation of the equipment is detected can be suppressed, and the increase in power consumption of the load device 200 due to the operation of the equipment can be handled by PWM operation.

[0054] Furthermore, in the second embodiment, the boost circuit 30 is already activated at timing f, before the operation of the equipment is detected at timing j. This reduces the waiting time from the operation of the equipment until the load device 200 moves (for example, from door operation until latch release).

[0055] Figure 5 shows an example of the configuration of an electric motor equipped with a power supply device according to the third embodiment. In the third embodiment, the description of the configuration, operation, and effects similar to those of the first and second embodiments will be omitted or simplified by referring to the above description.

[0056] The electric motor 103 shown in Figure 5 comprises a power supply unit 3 and a load unit 200. The power supply unit 3 differs from the first embodiment in that it includes a charging circuit 20 and a boost circuit 30, and does not include a power supply path 80.

[0057] Figure 6 is a timing chart showing an example of the operation of the power supply device according to the third embodiment. In the third embodiment, current is always supplied from the boost circuit 30 to the load device 200, both under normal and abnormal conditions.

[0058] In the third embodiment, the control circuit 50 starts the boost circuit 30 immediately after the start of power input from the power system 90, and operates the boost circuit 30 in a continuous boosting mode so that current is constantly supplied from the boost circuit 30 to the load device 200. When the control circuit 50 is operating the boost circuit 30 to supply current from the boost circuit 30 to the load device 200, if a vehicle abnormality is detected by the emergency signal E at timing f, the control circuit 50 switches the boosting operation of the boost circuit 30 to intermittent operation or PFM operation. When the control circuit 50 detects the operation of an equipment by the operation detection signal S, it switches the boost circuit 30 to PWM operation. This eliminates the momentary interruption time when switching power from the power system 90 to the energy storage device 10, even if the power input from the power system 90 is interrupted. In addition, by switching to intermittent operation or PFM operation when an abnormality is detected, the increase in power consumption until the operation of the equipment is detected can be suppressed.

[0059] Figure 7 shows an example of the configuration of an electric motor equipped with a power supply device according to the fourth embodiment. In the fourth embodiment, the description of the configuration, operation, and effects, which are the same as those of the first, second, and third embodiments, will be omitted or simplified by referring to the above description.

[0060] The electric motor 104 shown in Figure 7 comprises a power supply unit 4 and a load unit 200. The power supply unit 4 differs from the first embodiment in that it includes a diode 71.

[0061] Figure 8 is a timing chart showing an example of operation of the power supply unit according to the fourth embodiment. In the fourth embodiment, the control circuit 50 starts the bidirectional buck-boost converter 60 in charging mode immediately after the start of power input from the power system 90, and operates the bidirectional buck-boost converter 60 as a buck converter (charging circuit). If the voltage Vc is lower than the first threshold Vth1, the control circuit 50 charges the energy storage device 10 until the voltage Vc rises to the second threshold Vth2. Due to the charging operation, the voltage Vc of the energy storage device 10 gradually increases. When the voltage Vc rises to the second threshold Vth2, the control circuit 50 stops the charging operation of the bidirectional buck-boost converter 60.

[0062] In the fourth embodiment, when the control circuit 50 detects a vehicle abnormality at timing f by an emergency signal E, it switches the bidirectional buck-boost converter 60 from charging mode to boost mode, causing the bidirectional buck-boost converter 60 to operate as a boost converter (boost circuit). The control circuit 50 may also switch the bidirectional buck-boost converter 60 from charging mode to boost mode when it detects the operation of an equipment by an operation detection signal S, causing the bidirectional buck-boost converter 60 to operate as a boost converter (boost circuit).

[0063] In the fourth embodiment, the control circuit 50 operates the bidirectional buck-boost converter 60 in charging mode under normal conditions. This allows the power input via the power supply path 80 to be supplied to both the bidirectional buck-boost converter 60 and the load device 200 under normal conditions.

[0064] Although embodiments have been described above, the present invention is not limited to the embodiments described above. Various modifications and improvements are possible, such as combinations or substitutions with some or all of the other embodiments.

[0065] Figure 9 shows a table summarizing the above-mentioned operation examples for each embodiment. Step-down ON or charging ON indicates the execution of step-down operation (charging operation), and step-down OFF or charging OFF indicates the cessation of step-down operation (charging operation). Boost ON indicates the execution of boost operation, and boost OFF indicates the cessation of boost operation. [Explanation of Symbols]

[0066] 1,2,3,4 Power supply 10 Energy storage devices Cells 11, 12 20 Charging circuit 30 Boost Circuit 40 Equalization circuit 41, 42 resistors 50 Control circuits 51 Regulator 52 Bypass 60 Bidirectional Step-Up / Step-Down Converters 65 Output Nodes 71,72 diodes 80 Power supply path 81 Backflow prevention circuit 82 Overcurrent prevention circuit 83 Resistors 90 Power system 101,102,103,104 Electric equipment 200 load device 210 load 220 Drive Circuit

Claims

1. Energy storage devices, A charging circuit that, when the voltage of the energy storage device drops to a first threshold, starts charging the energy storage device based on the input power from the vehicle's power system, and stops charging the energy storage device when the voltage of the energy storage device rises to a second threshold higher than the first threshold, A boost circuit for boosting the voltage of the aforementioned energy storage device, A power supply device comprising: a control circuit that, when the input voltage corresponding to the input power from the power system is normal, causes the boost circuit to operate in a boosting operation so that a boost voltage higher than the voltage of the energy storage device is supplied to the load device at a constant voltage.

2. The power supply device according to claim 1 or later, comprising a power supply path having one end connected to the power system and the other end connected to the boost voltage output node.

3. The power supply device according to claim 2, wherein the boost circuit is a bidirectional buck-boost converter equipped with the charging circuit.

4. The power supply device according to claim 3, wherein the control circuit causes the bidirectional buck-boost converter to charge based on the power input from the output node via the power supply path so that the energy storage device is charged.

5. The power supply device according to claim 4, wherein the control circuit operates the bidirectional buck-boost converter to charge when the voltage of the energy storage device drops to a first threshold, and stops the bidirectional buck-boost converter to charge when the voltage of the energy storage device rises to a second threshold.

6. The aforementioned load device is a device that controls the operation of equipment operated by the user, The power supply device according to any one of claims 3 to 5, wherein the control circuit causes the bidirectional buck-boost converter to perform a boost operation when the equipment is being operated.

7. The power supply device according to claim 6, wherein the control circuit stops the boosting operation of the bidirectional buck-boost converter when the equipment is not being operated.

8. The power supply device according to any one of claims 3 to 5, wherein the control circuit switches the bidirectional step-up / step-up converter from charging mode to step-up mode when an abnormality is detected in the vehicle.

9. The aforementioned load device is a device that controls the operation of equipment operated by the user, The power supply device according to any one of claims 3 to 5, wherein the control circuit switches the bidirectional buck-boost converter from charging mode to boost mode when operation of the equipment is detected.

10. The power supply device according to claim 2, wherein the control circuit operates the boost circuit such that the boost voltage is lower than the voltage of the power supply path.

11. The power supply device according to claim 10, wherein the control circuit, when an abnormality in the vehicle is detected, starts the boosting operation of the boosting circuit so that current is supplied from the boosting circuit to the load device.

12. The aforementioned load device is a device that controls the operation of equipment operated by the user, The power supply device according to claim 11, wherein the control circuit, when an abnormality in the vehicle is detected, starts the boost circuit in intermittent operation or PFM operation, and when operation of the equipment is detected, switches the boost circuit to PWM operation.

13. The aforementioned load device is a device that controls the operation of equipment operated by the user, The power supply device according to claim 1, wherein when the control circuit is operating the boost circuit to supply current from the boost circuit to the load device, if an abnormality in the vehicle is detected, the control circuit switches the boost operation of the boost circuit to intermittent operation or PFM operation, and thereafter, when operation of the equipment is detected, the boost operation of the boost circuit switches to PWM operation.

14. The power supply device according to any one of claims 1 to 13, comprising a regulator that generates the power supply voltage of the control circuit based on power supplied from either the power system or the energy storage device.

15. The power supply device according to claim 14, further comprising a diode whose anode is connected to the output side of the energy storage device and whose cathode is connected to the input side of the regulator.

16. Energy storage devices, A charging circuit that charges the energy storage device based on the input power from the vehicle's power system, A boost circuit for boosting the voltage of the aforementioned energy storage device, A power supply device comprising: a control circuit that, when the input voltage corresponding to the input power from the power system is normal, causes the boost circuit to operate in a boosting operation so that a boost voltage higher than the voltage of the energy storage device is supplied to the load device at a constant voltage, regardless of whether the power system is faulty or in an emergency.

17. An electric motor comprising a power supply device according to any one of claims 1 to 16 and the load device.

18. The electric device according to claim 17, wherein the load device is a device that controls the operation of equipment operated by a user.

19. The electric device according to claim 18, wherein the equipment is an opening / closing body.

20. Energy storage devices, A charging circuit that, when the voltage of the energy storage device drops to a first threshold, starts charging the energy storage device based on the input power from the vehicle's power system, and stops charging the energy storage device when the voltage of the energy storage device rises to a second threshold higher than the first threshold, A boost circuit for boosting the voltage of the aforementioned energy storage device, A power supply device comprising: a control circuit that, when the input voltage corresponding to the input power from the power system is normal and the operation of the equipment is detected, causes the boost circuit to operate in a boosting operation mode so that a boost voltage higher than the voltage of the energy storage device is supplied at a constant voltage to a load device that controls the operation of the equipment.

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