Vehicle power supply unit and door latch device

Abstract

To provide a vehicular power supply device which is capable of stably operating a motor even when a battery voltage fluctuates significantly.SOLUTION: A vehicular power supply device 1 comprises: a backup power supply 6 which is supplied with power by a battery 3 mounted on a vehicle; a voltage boosting part 20 for boosting the voltage of the backup power supply 6 to a boosted voltage Vb; a motor driving part 7 which is connected to the battery 3 and the voltage boosting part 20 and is capable of driving an electric motor 2 by being supplied with power by one of them that has higher voltage than the other; and a control part 8 for controlling operation of the voltage boosting part 20. When the control part 8 determines that a predetermined voltage boosting condition is established, it boosts the voltage of the backup power supply 6 to a higher voltage than the rated voltage of the battery 3 by controlling the voltage boosting part 20.SELECTED DRAWING: Figure 1

Description

Technical Field

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[0001] The present invention relates to a vehicle power supply device and a door latch device.

Background Art

[0002] Citation Document 1 discloses a vehicle door lock system that operates a door lock motor by the power supplied from a battery provided on the vehicle body side to perform the locking operation and unlocking operation of a vehicle door. In this system, a backup power source charged by the power from the battery is provided on the vehicle door, and when the power supply from the battery to the door lock motor is interrupted, the door lock motor is operated by supplying power from the backup power source.

Prior Art Documents

Patent Documents

[0003]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0004] In a power supply device capable of supplying power from a backup power source to a motor, such as the vehicle door lock system of Patent Document 1, when the power supply from the battery to the motor is not interrupted, that is, during normal operation, the motor always operates by the power from the battery. However, the voltage of the battery may vary greatly from its rated voltage, and there may be cases where the motor cannot be operated stably.

[0005] An object of the present invention is to provide a vehicle power supply device capable of stably operating a motor even when the voltage of the battery varies greatly.

Means for Solving the Problems

[0006] One aspect of the present invention is, A backup power supply that is powered by the vehicle's battery, A boost unit that increases the voltage of the backup power supply to a boosted voltage, A motor drive unit connected to the battery and the voltage booster, which is powered by the higher voltage of the two and is capable of driving an electric motor, A control unit that controls the operation of the voltage boosting unit and Equipped with, The control unit, The control unit is configured to receive at least one of a collision signal indicating that a vehicle has collided and a battery status signal capable of determining the state of the battery, and the predetermined boost condition is met when the control unit has not received the collision signal and when the control unit has determined, based on the battery status signal, that the battery is not in a faulty state or is not in a shut-off state, and the The present invention provides a vehicle power supply device that, when it is determined that predetermined voltage boosting conditions are met, controls the voltage boosting unit to boost the voltage of the backup power supply to a voltage greater than the rated voltage of the battery.

[0007] According to the present invention, when predetermined voltage boosting conditions are met, the voltage of the backup power supply is boosted to a voltage greater than the rated voltage of the battery, so that power is supplied from the backup power supply to the electric motor. As a result, even if the voltage of the vehicle battery fluctuates, the electric motor can be operated stably by power from the backup power supply without being affected by the fluctuations. [Effects of the Invention]

[0008] According to the present invention, the motor can be operated stably even when the battery voltage fluctuates significantly. [Brief explanation of the drawing]

[0009] [Figure 1] Circuit diagram of a vehicle power supply device according to the first embodiment of the present invention. [Figure 2] Circuit diagram of a vehicle power supply device according to a second embodiment of the present invention. [Figure 3] Circuit diagram of a vehicle power supply device according to a third embodiment of the present invention. [Figure 4] Circuit diagram of a vehicle power supply device according to the fourth embodiment of the present invention. [Modes for carrying out the invention]

[0010] A vehicle power supply device according to one embodiment of the present invention will be described below with reference to the attached drawings. The following description is essentially illustrative and is not intended to limit the present invention, its applications, or its uses.

[0011] [First Embodiment] Figure 1 is a circuit diagram of a vehicle power supply device 1 according to a first embodiment of the present invention. The vehicle power supply device 1 is a device for supplying power to an electric motor 2 that performs locking and unlocking operations of a door latch device 10 provided in a vehicle door (not shown).

[0012] The door latch device 10 includes a fork 12 that can rotate between a latch position in which it engages with a striker 11 on the vehicle body side and an open position in which the engagement is released, and a claw 13 that can rotate between a locking position in which it holds the fork 12 in the latch position and an unlocked position in which it releases the lock. The vehicle door is also provided with a door lock switch 14 that the user operates to lock and unlock the door latch device 10. By operating the door lock switch 14, the claw 13 is rotated via the electric motor 2, thereby locking or unlocking the vehicle door.

[0013] The vehicle power supply unit 1 has a battery 3 installed in the vehicle body. The vehicle power supply unit 1 also has a motor drive unit 7 capable of driving an electric motor 2 inside the vehicle door, and a control unit 8 that controls the operation of the vehicle power supply unit 1. The battery 3 has a rated voltage of DC 12V.

[0014] Battery 3 stores the power necessary for the operation of the vehicle and supplies power to on-board equipment such as the prime mover and electrical components as needed. When the amount of stored power decreases, it is recharged by a generator (not shown) rotated by the prime mover (not shown) or by a regenerative brake (not shown). Battery 3 has an output terminal 3a to which the stored power is output and a ground terminal 3b that is grounded.

[0015] The motor drive unit 7 has an input terminal 7a to which power is supplied, an output terminal 7b that supplies power to the electric motor 2, a control terminal 7c to which a control signal from the control unit 8 is input, and a grounded ground terminal 7d. The control terminal 7c is connected to the control unit 8 via the first control signal line 41. The motor drive unit 7 supplies power to the electric motor 2 so as to rotate the electric motor 2 forward or backward based on the control signal input to the control terminal 7c.

[0016] The output terminal 3a of the battery 3 and the input terminal 7a of the motor drive unit 7 are connected by two systems including the first power supply line 31 and the second power supply line 32 that are connected in parallel to each other. The first power supply line 31 connects the output terminal 3a of the battery 3 and the input terminal 7a of the motor drive unit 7 via a reverse current preventing diode 37, and the voltage output from the battery 3 is supplied to the motor drive unit 7.

[0017] On the other hand, a first relay 9, a backup power supply 6, and a booster unit 20 are provided in order from the output terminal 3a side on the second power supply line 32, and the boosted voltage Vb obtained by boosting the power output from the backup power supply 6 by the booster unit 20 is supplied to the motor drive unit 7. That is, the motor drive unit 7 is supplied with the higher of the output voltage of the battery 3 supplied via the first power supply line 31 and the boosted voltage Vb supplied from the booster unit 20 via the second power supply line 32.

[0018] The booster unit 20 has a booster circuit 26 that boosts the voltage of the backup power supply 6 to the boosted voltage Vb, and a voltage dividing circuit 50 that divides the boosted voltage Vb.

[0019] The booster circuit 26 has, in series from the battery 3 side, a coil 21 and a diode 22 provided on the second power supply line 32. The backup power supply 6 is interposed between the first relay 9 and the coil 21 on the second power supply line 32. One end 6a of the backup power supply 6 is connected to the second power supply line 32, and the other end 6b is grounded. The backup power supply 6 is a capacitor in the present embodiment and stores electricity at a voltage of about DC3V to DC5V.

[0020] The first relay 9 is connected to the control unit 8 via the second control signal line 42. The first relay 9 is configured as a normally open type and conducts when a control signal is input from the control unit 8. When the first relay 9 conducts, the backup power supply 6 is connected to the battery 3 and stores the power supplied from the battery 3.

[0021] An electric field effect transistor 23 is interposed between the coil 21 and the diode 22 on the second power supply line 32. The electric field effect transistor 23 has a source 23a, a drain 23b, and a gate 23c. The source 23a is grounded. The drain 23b is connected to the second power supply line 32. The output terminal 24a of the boost IC 24 is connected to the gate 23c.

[0022] In addition to the output terminal 24a, the boost IC 24 has a feedback terminal 24b and a control terminal 24c. A voltage obtained by dividing the boost voltage Vb by the voltage dividing circuit 50 is input as a feedback voltage Vf to the feedback terminal 24b. The control terminal 24c is connected to the control unit 8 via the third control signal line 43. The boost IC 24 outputs a control signal from the output terminal 24a to the gate 23c based on the control signal from the control unit 8.

[0023] Specifically, the electric field effect transistor 23 turns on upon receiving the control signal input to the gate 23c, and conducts between the source 23a and the drain 23b, thereby supplying current from the backup power supply 6 to the coil 21 and accumulating electrical energy in the coil 21 as magnetic energy. Next, the boost IC 24 turns off the electric field effect transistor 23, thereby releasing the conduction between the source 23a and the drain 23b and discharging the magnetic energy accumulated in the coil 21 as electrical energy.

[0024] The boost IC 24 outputs a control signal to the field-effect transistor 23, causing it to repeatedly switch on and off, thereby repeatedly accumulating and releasing energy in the coil 21. The boost IC 24 increases the voltage from the backup power supply 6 until the feedback voltage Vf reaches a predetermined target voltage V0. As a result, the voltage output from the backup power supply 6 is output as the boosted voltage Vb.

[0025] On the second power supply line 32, a capacitor 25 is interposed on the motor drive unit 7 side relative to the diode 22. One end 25a of the capacitor 25 is connected to the second power supply line 32, and the other end 25b is grounded. Since the diode 22 and capacitor 25 are located on the motor drive unit 7 side relative to the field-effect transistor 23, the voltage fluctuation of the boosted voltage Vb is suppressed by the diode 22 and capacitor 25.

[0026] As described above, the coil 21, diode 22, field-effect transistor 23, boost IC 24, and capacitor 25 constitute a boost circuit 26 that boosts the voltage output from the backup power supply 6 to a boost voltage Vb.

[0027] The voltage divider circuit 50 is interposed on the motor drive unit 7 side relative to the capacitor 25 on the second power supply line 32. The voltage divider circuit 50 includes a first resistor 51, a second resistor 52, a third resistor 53, and a second relay 54 (switching element). One end 51a of the first resistor 51 is connected to the output terminal 26b of the boost circuit 26, and the other end 51b is connected to the feedback terminal 24b of the boost IC 24.

[0028] The second resistor 52 has one end 52a connected to the other end 51b of the first resistor 51, and the other end 52b is grounded. The third resistor 53 and the second relay 54 are connected in series to form a switching circuit 55. The switching circuit 55 is connected in parallel to the second resistor 52. In this embodiment, the second relay 54 is located on the second power supply line 32 side of the third resistor 53.

[0029] The switching circuit 55 has one end 55a connected to the other end 51b of the first resistor 51, and the other end 55b connected to the other end 52b of the second resistor 52. The second relay 54 is connected to the control unit 8 via the fourth control signal line 44. The second relay 54 is configured to be normally closed and opens when a control signal is input from the control unit 8.

[0030] In the voltage divider circuit 50, when the second relay 54 is closed, the first resistor 51 and the combined resistor 50Z, which consists of the second resistor 52 and the third resistor 53, are connected in series. On the other hand, when the second relay 54 is open, the first resistor 51 and the second resistor 52 are connected in series. Here, the resistance value of the combined resistor 50Z is smaller than that of the second resistor 52. As a result, the voltage drop across the first resistor 51 when the second relay 54 is closed is greater than the voltage drop across the first resistor 51 when the second relay 54 is open.

[0031] In other words, by controlling the closing / opening of the second relay 54, the voltage division ratio, which represents the ratio of the resistance value of the first resistor 51 to the total resistance value of the voltage division circuit 50, is adjusted, and the voltage at the other end 51b can be adjusted. That is, the voltage division modification circuit 56 is composed of the second resistor 52, the third resistor 53, and the second relay 54.

[0032] Specifically, when the second relay 54 is closed, the voltage division ratio by the first resistor 51 becomes relatively larger, so the voltage at the other end 51b (feedback voltage Vf) becomes relatively smaller. On the other hand, when the second relay 54 is switched to open, the voltage division ratio by the first resistor 51 becomes relatively smaller, so the voltage at the other end 51b (feedback voltage Vf) becomes relatively larger.

[0033] As described above, the boost IC 24 adjusts the boost voltage Vb so that the feedback voltage Vf input from the feedback terminal 24b becomes a predetermined value. Therefore, due to the voltage drop across the first resistor 51, the first boost voltage Vb1 when the second relay 54 is closed is greater than the second boost voltage Vb2 when the second relay 54 is open.

[0034] The first resistor 51, the second resistor 52, and the third resistor 53 are set such that the first boost voltage Vb1 is greater than the rated voltage of battery 3, which is 12V, and the second boost voltage Vb2 is greater than or equal to the minimum voltage at which the electric motor 2 operates, but less than the rated voltage of battery 3. The operating voltage of the electric motor 2 is between DC 9V and DC 16V.

[0035] In this embodiment, the resistance value R1 of the first resistor 51 is set to 142kΩ, the resistance value R2 of the second resistor 52 is set to 22kΩ, and the resistance value R3 of the third resistor 53 is set to 40kΩ, so that the first boost voltage Vb1 becomes DC14V and the second boost voltage Vb2 becomes DC9.5V. The target voltage V0 of the feedback voltage Vf is set to DC1.274V.

[0036] To explain in more detail, when the second relay 54 is closed, the resistance value R0 of the combined resistor 50Z, which consists of the second resistor 52 and the third resistor 53, is calculated by the following equation (1) and is approximately 14.2kΩ. Therefore, the voltage division ratio between the first resistor 51 and the combined resistor 50Z is 142:14.2, and the first boost voltage Vb1 when the feedback voltage Vf becomes the target voltage V0 is calculated to be approximately 14V from the following equation (2).

[0037]

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[0038]

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[0039] On the other hand, when the second relay 54 is open, the voltage division ratio between the first resistor 51 and the second resistor 52 is 142:22, and the second boost voltage Vb2 when the feedback voltage Vf becomes the target voltage V0 can be calculated to be approximately 9.5V from the following equation (3).

[0040]

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[0041] Therefore, by switching the second relay 54 between closed and open, the boost IC 24 controls the field-effect transistor 23 so that the feedback voltage Vf becomes the target voltage V0, thereby switching the voltage output from the backup power supply 6 to either the first boost voltage Vb1 or the second boost voltage Vb2 and boosting it.

[0042] The control unit 8 is connected to a third power supply line 33 and a fourth power supply line 34, which receive voltage from the battery 3. The third power supply line 33 supplies operating power from the battery 3 to the control unit 8. One end 33a is connected to the battery 3 side of the first relay 9 on the second power supply line 32, and the other end 33b is connected to the control unit 8. A regulator 5 is interposed in the third power supply line 33, and the power from the battery 3 is stepped down to 5V before being supplied to the control unit 8.

[0043] The fourth power supply line 34 has one end 34a connected to the battery 3 side relative to the regulator 5 on the third power supply line 33, and the other end 34b connected to the control unit 8. The control unit 8 determines whether the battery 3 is functioning normally, for example, whether the battery is not dead, based on the voltage supplied to the battery 3 via the fourth power supply line 34.

[0044] Furthermore, the control unit 8 receives a collision signal output from the ECU 4 located on the vehicle body. In this embodiment, the ECU 4 determines whether the vehicle is in a collision state based on input signals from the acceleration sensor 16 and the millimeter-wave radar 17, and outputs a collision signal to the control unit 8 when it determines that the vehicle is in a collision state or is expected to reach a collision state. The control unit 8 determines whether the vehicle is not in a collision state based on the presence or absence of the collision signal from the ECU 4.

[0045] The control unit 8 determines that the predetermined voltage boosting conditions have been met when it determines that the battery 3 is functioning normally and the vehicle is not in a collision state. In other words, the control unit 8 determines that the predetermined voltage boosting conditions have not been met when it is not determined that at least one of the following conditions is not met: the battery 3 is functioning normally and the vehicle is not in a collision state.

[0046] Furthermore, the control unit 8 receives a control signal output from the door lock switch 14. Based on the control signal from the door lock switch 14, the control unit 8 determines whether or not the door lock switch 14 has been operated.

[0047] As described above, the control unit 8 is connected to the first to fourth control signal lines 41 to 44. The control unit 8 outputs control signals to the motor drive unit 7, the first relay 9, the boost IC 24, and the second relay 54 via the first to fourth control signal lines 41 to 44.

[0048] The control unit 8 consists of a well-known computer equipped with memory, storage device and arithmetic processing unit (CPU), and software implemented on the computer. The control unit 8 includes a boost condition determination unit 81, a first relay control unit 82, a door lock switch operation determination unit 83, a second relay control unit 84, a boost IC control unit 85, and a motor drive control unit 86.

[0049] The voltage boost condition determination unit 81 determines whether the battery 3 is functioning correctly based on the voltage supplied to the battery 3 from the fourth power supply line 34, and also determines whether the vehicle is not in a collision state based on the presence or absence of a collision signal from the ECU 4. The voltage boost condition determination unit 81 determines whether both conditions, namely that the battery 3 is functioning correctly and the vehicle is not in a collision state, are met, i.e., whether a predetermined voltage boost condition is met.

[0050] The first relay control unit 82 charges the backup power supply 6 from the battery 3 as needed by making the first relay 9 conduct. The door lock switch operation determination unit 83 determines whether the door lock switch 14 has been operated based on the signal from the door lock switch 14. The second relay control unit 84 inputs a control signal to the second relay 54 and opens it when the boost condition determination unit 81 determines that the predetermined boost condition is not met. The boost IC control unit 85 controls the boost IC 24 based on the operation of the door lock switch 14 to boost the voltage of the power output from the backup power supply 6 to the boost voltage Vb. The motor drive control unit 86 controls the motor drive unit 7 to rotate the electric motor 2 in the forward or reverse direction.

[0051] Next, the operation of the vehicle power supply unit 1 will be explained.

[0052] First, the control unit 8, at a predetermined timing, activates the first relay 9 via the first relay control unit 82 to supply power from the battery 3 to the backup power supply 6. This allows the backup power supply 6 to be appropriately charged in preparation for the locking or unlocking operation of the door latch device 10.

[0053] When the control unit 8 determines that the door lock switch 14 has been operated by the door lock switch operation determination unit 83, the boost condition determination unit 81 determines whether a predetermined boost condition has been met. If it is determined that the predetermined boost condition has been met, the boost IC control unit 85 operates the boost IC 24 without controlling the second relay 54 by the second relay control unit 84, and boosts the voltage output from the backup power supply 6 to the first boost voltage Vb1 so that the feedback voltage Vf becomes the target voltage V0.

[0054] Here, the first boosted voltage Vb1 is greater than the rated voltage of the battery 3, so power is supplied to the motor drive unit 7 at the first boosted voltage Vb1. The control unit 8 controls the motor drive unit 7 to operate the electric motor 2 with the first boosted voltage Vb1. Since fluctuations in the first boosted voltage Vb1 are suppressed, the electric motor 2 can be operated stably.

[0055] On the other hand, when the control unit 8 determines that the door lock switch 14 has been operated by the door lock switch operation determination unit 83, and the boost condition determination unit 81 determines that the predetermined boost condition is not met, the control unit 84 controls the second relay 54 to open. Next, the boost IC control unit 85 operates the boost IC 24 to boost the voltage output from the backup power supply 6 to the second boost voltage Vb2 so that the feedback voltage Vf becomes the target voltage V0.

[0056] At this time, since the predetermined voltage boosting conditions are not met, the power supply from battery 3 is cut off, and power is supplied to the motor drive unit 7 with a second boost voltage Vb2 that is lower than the rated voltage of battery 3. The control unit 8 controls the motor drive unit 7 to operate the electric motor 2 with the second boost voltage Vb2. Since the fluctuation of the second boost voltage Vb2 is suppressed, the electric motor 2 can be operated stably.

[0057] The vehicle power supply device 1 according to the embodiment described above provides the following effects.

[0058] (1) When the predetermined boosting conditions are met, the voltage of the backup power supply 6 is boosted to a first boost voltage Vb1 which is greater than the rated voltage of the battery 3, and power is supplied from the backup power supply 6 to the electric motor 2. As a result, even if the voltage of the battery 3 fluctuates, the electric motor 2 can be operated stably by power from the backup power supply 6 without being affected by the fluctuations.

[0059] (2) When the control unit 8 determines that the predetermined voltage boosting conditions are not met, it controls the second relay 54 and the boost IC 24 to boost the voltage of the backup power supply 6 to a level lower than the rated voltage of the battery 3 and to a level higher than the minimum operating voltage of the electric motor 2.

[0060] As a result, when the predetermined boosting conditions are not met, the boosting of the backup power supply 6 to an unnecessarily large size is suppressed, thereby reducing power consumption.

[0061] (3) The boost unit 20 includes a boost circuit 26 that boosts the voltage of the backup power supply 6 to a boost voltage Vb, and a voltage divider circuit 50 that divides the boost voltage Vb. The boost circuit 26 receives the voltage divided by the voltage divider circuit 50 as a feedback voltage Vf and adjusts the boost voltage Vb so that the feedback voltage Vf becomes a predetermined target voltage V0. The voltage divider circuit 50 has a voltage divider changing circuit 56 configured to change the voltage division ratio.

[0062] As a result, the feedback voltage Vf can be adjusted by changing the voltage division ratio, and the boosted voltage Vb can be easily adjusted based on the feedback voltage Vf. In other words, by providing a voltage division change circuit 56 to the voltage division circuit 50, the boosted voltage Vb can be increased to a voltage greater than the rated voltage of the battery 3 at low cost.

[0063] (4) The voltage divider circuit 50 includes a first resistor 51, one end 51a of which is connected to the output terminal 26b of the boost circuit 26 and the other end 51b of which is connected to the feedback terminal 24b of the boost IC 24, and a second resistor 52, one end 52a of which is connected to the other end 51b of the first resistor 51 and the other end 52b of which is grounded. The voltage divider change circuit 56 includes a switching circuit 55 in which a third resistor 53 and a second relay 54 are connected in series, and the switching circuit 55 is configured to be connected in parallel with the second resistor 52. The second relay 54 is closed by the control unit 8 when a predetermined boost condition is met, and the first resistor 51, the second resistor 52 and the third resistor 53 set the voltage divider change circuit 56 such that the boosted voltage Vb is greater than the rated voltage of the battery 3 when the second relay 54 is closed.

[0064] As a result, a voltage divider circuit 50 having a voltage divider changing circuit 56 can be constructed at low cost using the first resistor 51, the second resistor 52, the third resistor 53, and the second relay 54. Furthermore, the voltage division ratio can be easily changed using the switching circuit 55.

[0065] (5) The control unit 8 is configured to receive a collision signal indicating that a vehicle has collided and a battery status signal that allows it to determine the state of the battery 3. The predetermined voltage boosting conditions are met when the control unit 8 has not received a collision signal and when the control unit 8 has determined, based on the battery status signal, that the battery 3 is not in a faulty state or is not in a shut-off state.

[0066] As a result, in situations where power cannot be supplied from battery 3 to motor drive unit 7 due to, for example, a vehicle collision or battery failure, power is supplied to motor drive unit 7 from backup power supply 6, so it is not necessary to increase the boosted voltage Vb above the rated voltage of battery 3. By determining that the predetermined boosting conditions for increasing the boosted voltage Vb are met when no collision signal indicating a vehicle collision is received, and when it is determined that battery 3 is not in a faulty state or a shut-off state, the boosted voltage Vb can be increased above the rated voltage of battery 3 in appropriate situations.

[0067] [Second Embodiment] Figure 2 is a circuit diagram of the vehicle power supply unit 100 according to the second embodiment. The vehicle power supply unit 100 according to the second embodiment is configured similarly to the vehicle power supply unit 1 according to the first embodiment, except that the configuration of the voltage divider circuit 150 is different. In the following description, the same reference numerals are used for elements that are the same as those in the vehicle power supply unit 1 according to the first embodiment, and their descriptions are omitted.

[0068] The voltage divider circuit 150 is interposed on the motor drive unit 7 side relative to the capacitor 25 on the second power supply line 32. The voltage divider circuit 150 includes a first resistor 151, a second resistor 152, a third resistor 153, and a second relay 154 (switching element). One end 151a of the first resistor 151 is connected to the output terminal 26b of the boost circuit 26, and the other end 151b is connected to the feedback terminal 24b of the boost IC 24.

[0069] The second resistor 152 has one end 152a connected to the other end 151b of the first resistor 151, and the other end 152b is grounded. The third resistor 153 and the second relay 154 are connected in series to form a switching circuit 155. The switching circuit 155 is connected in parallel to the first resistor 151. In this embodiment, the second relay 154 is located on the second power supply line 32 side of the third resistor 153.

[0070] The switching circuit 155 has one end 155a connected to one end 151a of the first resistor 151, and the other end 155b connected to the other end 151b of the first resistor 151. The second relay 154 is connected to the control unit 8 via the fourth control signal line 144. The second relay 154 is configured to be normally open and closes when a control signal is input from the control unit 8.

[0071] In the voltage divider circuit 150, when the second relay 154 is open, the first resistor 151 and the second resistor 152 are connected in series. On the other hand, when the second relay 154 is closed, the combined resistor 150Z, consisting of the first resistor 151 and the third resistor 153, is connected in series with the second resistor 152. Here, the resistance value of the combined resistor 150Z is smaller than that of the first resistor 151. As a result, the voltage drop across the combined resistor 150Z (i.e., the first resistor 151) when the second relay 154 is open is greater than the voltage drop across the combined resistor 150Z when the second relay 154 is closed.

[0072] In other words, by controlling the closing / opening of the second relay 154, the voltage division ratio, which represents the ratio of the resistance value of the combined resistance 150Z to the total resistance value of the voltage division circuit 150, is adjusted, and the voltage at the other end 151b can be adjusted. That is, the voltage division modification circuit 156 is configured by the first resistor 151, the third resistor 153, and the second relay 154.

[0073] Specifically, when the second relay 154 is open, the voltage division ratio due to the combined resistance 150Z becomes relatively large, so the voltage at the other end 151b (feedback voltage Vf) becomes relatively small. On the other hand, when the second relay 154 is switched to closed, the voltage division ratio due to the combined resistance 150Z becomes relatively small, so the voltage at the other end 151b (feedback voltage Vf) becomes relatively large.

[0074] As described above, the boost IC 24 adjusts the boost voltage Vb so that the feedback voltage Vf input from the feedback terminal 24b becomes a predetermined value. Therefore, due to the voltage drop across the combined resistance 150Z, the first boost voltage Vb1 when the second relay 154 is open is greater than the second boost voltage Vb2 when the second relay 154 is closed.

[0075] The first resistor 151, the second resistor 152, and the third resistor 153 are set such that the first boost voltage Vb1 is greater than the rated voltage of battery 3, which is 12V, and the second boost voltage Vb2 is greater than or equal to the minimum voltage at which the electric motor 2 operates, but less than the rated voltage of battery 3. The operating voltage of the electric motor 2 is between DC 9V and DC 16V.

[0076] In this embodiment, the resistance value R21 of the first resistor 151 is set to 220kΩ, the resistance value R22 of the second resistor 152 is set to 22kΩ, and the resistance value R23 of the third resistor 153 is set to 400kΩ, so that the first boost voltage Vb1 becomes DC14V and the second boost voltage Vb2 becomes DC9.5V. The target voltage V0 of the feedback voltage Vf is set to DC1.274V.

[0077] To explain in more detail, when the second relay 154 is open, the voltage division ratio of the combined resistance 150Z and the second resistor 152 is 220:22, and the first boost voltage Vb1 when the feedback voltage Vf becomes the target voltage V0 can be calculated to be approximately 14V from the following equation (4).

[0078]

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[0079] On the other hand, when the second relay 154 is closed, the resistance value R20 of the combined resistor 150Z, which consists of the first and third resistors, is calculated by the following equation (5) and is approximately 142kΩ. Therefore, the voltage division ratio between the combined resistor 150Z and the second resistor 152 is 142:22, and the second boost voltage Vb2 when the feedback voltage Vf becomes the target voltage V0 is calculated to be approximately 9.5V from the following equation (6).

[0080]

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[0081]

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[0082] Therefore, by switching the second relay 154 between closed and open, the boost IC 24 controls the field-effect transistor 23 so that the feedback voltage Vf becomes the target voltage V0, thereby switching the voltage output from the backup power supply 6 to either the first boost voltage Vb1 or the second boost voltage Vb2 and boosting it.

[0083] The voltage divider circuit 150 includes a first resistor 151, one end 151a of which is connected to the output terminal 26b of the boost circuit 26 and the other end 151b of which is connected to the feedback terminal 24b of the boost IC 24, and a second resistor 152, one end 152a of which is connected to the other end 151b of the first resistor 151 and the other end 152b of which is grounded. The voltage divider changing circuit 156 includes a switching circuit 155 in which a third resistor 153 and a second relay 154 are connected in series. The switching circuit 155 is configured to be connected in parallel with the first resistor 151. The second relay 154 is opened by the control unit 8 when a predetermined boost condition is met, and the first resistor 151, the second resistor 152, and the third resistor 153 set the voltage divider changing circuit 156 such that when the second relay 154 is open, the first boosted voltage Vb1 is greater than the rated voltage of the battery 3.

[0084] As a result, a voltage divider circuit 150 having a voltage divider changing circuit 156 can be constructed at low cost using the first resistor 151, the second resistor 152, the third resistor 153, and the second relay 154. Furthermore, the voltage division ratio can be easily changed using the switching circuit 155.

[0085] [Third Embodiment] Figure 3 is a circuit diagram of the vehicle power supply unit 200 according to the third embodiment. The vehicle power supply unit 200 according to the third embodiment is configured similarly to the vehicle power supply units 1,100 according to the first and second embodiments, except that the configuration of the voltage divider circuit 250 is different. In the following description, the same reference numerals are used for elements that are the same as those in the vehicle power supply unit 1 according to the first embodiment, and their descriptions are omitted.

[0086] The voltage divider circuit 250 is interposed on the motor drive unit 7 side relative to the capacitor 25 on the second power supply line 32. The voltage divider circuit 250 includes a first resistor 251, a second resistor 252, a third resistor 253, and a second relay 254 (switching element). One end 251a of the first resistor 251 is connected to the output terminal 26b of the boost circuit 26, and the other end 251b is connected to the feedback terminal 24b of the boost IC 24.

[0087] The second resistor 252 has one end 252a connected to the other end 251b of the first resistor 251. The third resistor 253 has one end 253a connected to the other end 252b of the second resistor 252, and the other end 253b is grounded. The second relay 254 is connected in parallel to the third resistor 253. That is, one end 254a of the second relay 254 is connected to one end 253a of the third resistor 253, and the other end 254b is connected to the other end 253b of the third resistor 253.

[0088] The second relay 254 is connected to the control unit 8 via the fourth control signal line 244. The second relay 254 is configured to be normally closed and opens when a control signal is input from the control unit 8.

[0089] In the voltage divider circuit 250, when the second relay 254 is closed, the first resistor 251 and the second resistor 252 are connected in series. On the other hand, when the second relay 254 is open, the first resistor 251, the second resistor 252, and the third resistor 253 are connected in series. As a result, the voltage drop across the first resistor 251 when the second relay 254 is closed is greater than the voltage drop across the first resistor 251 when the second relay 254 is open.

[0090] In other words, by controlling the closing / open state of the second relay 254, the voltage division ratio, which represents the ratio of the resistance value of the first resistor 251 to the total resistance value of the voltage division circuit 250, is adjusted, thereby adjusting the voltage at the other end 251b. That is, the third resistor 253 and the second relay 254 constitute the voltage division modification circuit 256.

[0091] Specifically, when the second relay 254 is closed, the voltage division ratio by the first resistor 251 becomes relatively larger, so the voltage at the other end 251b (feedback voltage Vf) becomes relatively smaller. On the other hand, when the second relay 254 is switched to open, the voltage division ratio by the first resistor 251 becomes relatively smaller, so the voltage at the other end 251b (feedback voltage Vf) becomes relatively larger.

[0092] As described above, the boost IC 24 adjusts the boost voltage Vb so that the feedback voltage Vf input from the feedback terminal 24b becomes a predetermined value. Therefore, due to the voltage drop across the first resistor 251, the first boost voltage Vb1 when the second relay 254 is closed is greater than the second boost voltage Vb2 when the second relay 254 is open.

[0093] The first resistor 251, the second resistor 252, and the third resistor 253 are set such that the first boost voltage Vb1 is greater than the rated voltage of battery 3, which is 12V, and the second boost voltage Vb2 is greater than or equal to the minimum voltage at which the electric motor 2 operates, but less than the rated voltage of battery 3. The operating voltage of the electric motor 2 is between DC 9V and DC 16V.

[0094] In this embodiment, the resistance value R31 of the first resistor 251 is set to 200kΩ, the resistance value R32 of the second resistor 252 is set to 20kΩ, and the resistance value R33 of the third resistor 253 is set to 11kΩ, so that the first boost voltage Vb1 becomes DC14V and the second boost voltage Vb2 becomes DC9.5V. The target voltage V0 of the feedback voltage Vf is set to DC1.274V.

[0095] To explain in more detail, when the second relay 254 is closed, the voltage division ratio of the first resistor 251 and the second resistor 252 is 200:20, and the first boost voltage Vb1 when the feedback voltage Vf becomes the target voltage V0 can be calculated to be approximately 14V from the following equation (7).

[0096]

number

[0097]

number

[0098] Therefore, by switching the second relay 254 between closed and open, the boost IC 24 controls the field-effect transistor 23 so that the feedback voltage Vf becomes the target voltage V0, thereby switching the voltage output from the backup power supply 6 to either the first boost voltage Vb1 or the second boost voltage Vb2 and boosting it.

[0099] Specifically, the voltage divider circuit 250 includes a first resistor 251, one end 251a of which is connected to the output terminal 26b of the boost circuit 26 and the other end 251b of which is connected to the feedback terminal 24b of the boost IC 24; a second resistor 252, one end 252a of which is connected to the other end 251b of the first resistor 251; and a third resistor 253, one end 253a of which is connected to the other end 252b of the second resistor 252 and the other end 253b of which is grounded. The voltage divider changing circuit 256 includes a second relay 254. The second relay 254 is configured to be connected in parallel with the third resistor 253. When a predetermined boost condition is met, the second relay 254 is closed by the control unit 8, and the first resistor 251, the second resistor 252, and the third resistor 253 set the voltage divider changing circuit 256 such that when the second relay 254 is closed, the first boost voltage Vb1 is greater than the rated voltage of the battery 3.

[0100] As a result, a voltage divider circuit 250 having a voltage divider changing circuit 256 can be constructed at low cost using the first resistor 251, the second resistor 252, the third resistor 253, and the second relay 254. Furthermore, the voltage division ratio can be easily changed using the second relay 254. In addition, regardless of whether the second relay 254 is closed or open, the first resistor 251, the second resistor 252, and the third resistor 253 are not connected in parallel with each other, so the combined resistance does not need to be considered, making it easier to construct the circuit.

[0101] Alternatively, the second relay 254 may be connected in parallel to the second resistor 252 instead of the third resistor 253. In this case, by setting the resistance value R31 of the first resistor 251 to 200kΩ, the resistance value R32 of the second resistor 252 to 11kΩ, and the resistance value R33 of the third resistor 253 to 20kΩ, the first boost voltage Vb1 and the second boost voltage Vb2 according to the above embodiment can be realized. Specifically, when the second relay 254 is closed, the voltage output from the backup power supply 6 can be boosted to the first boost voltage Vb1. When the second relay 254 is open, the voltage output from the backup power supply 6 can be boosted to the second boost voltage Vb2.

[0102] [Fourth Embodiment] Figure 4 is a circuit diagram of the vehicle power supply unit 300 according to the fourth embodiment. The vehicle power supply unit 300 according to the fourth embodiment is configured similarly to the vehicle power supply units 1, 100, and 200 according to the first, second, and third embodiments, except that the configuration of the voltage divider circuit 350 is different. In the following description, the same reference numerals are used for elements that are the same as those in the vehicle power supply unit 1 according to the first embodiment, and their descriptions are omitted.

[0103] The voltage divider circuit 350 is interposed on the motor drive unit 7 side relative to the capacitor 25 on the second power supply line 32. The voltage divider circuit 350 includes a first resistor 351, a second resistor 352, a third resistor 353, and a second relay 354 (switching element). One end 351a of the first resistor 351 is connected to the output terminal 26b of the boost circuit 26.

[0104] The second resistor 352 has one end 352a connected to the other end 351b of the first resistor 351, and the other end 352b connected to the feedback terminal 24b of the boost IC 24. The third resistor 353 has one end 353a connected to the other end 352b of the second resistor 352, and the other end 353b is grounded. The second relay 354 is connected in parallel with the second resistor 352. That is, one end 354a of the second relay 354 is connected to one end 352a of the second resistor 352, and the other end 354b is connected to one end 353a of the third resistor 353.

[0105] The second relay 354 is connected to the control unit 8 via the fourth control signal line 344. The second relay 354 is configured to be normally open and closes when a control signal is input from the control unit 8.

[0106] In the voltage divider circuit 350, when the second relay 354 is closed, the first resistor 351 and the third resistor 353 are connected in series. On the other hand, when the second relay 354 is open, the first resistor 351, the second resistor 352, and the third resistor 353 are connected in series. As a result, the voltage drop across the combined resistance 350Z, which consists of the first resistor 351 and the second resistor 352, when the second relay 354 is open is greater than the voltage drop across the combined resistance 350Z (i.e., the first resistor 351) when the second relay 354 is closed.

[0107] In other words, by controlling the closing / open state of the second relay 354, the voltage division ratio, which represents the ratio of the resistance value of the combined resistance 350Z to the total resistance value of the voltage division circuit 350, is adjusted, thereby adjusting the voltage at the other end 352b. That is, the voltage division modification circuit 356 is configured by the second resistor 352 and the second relay 354.

[0108] Specifically, when the second relay 354 is open, the voltage division ratio due to the combined resistance 350Z becomes relatively large, so the voltage at the other end 352b (feedback voltage Vf) becomes relatively small. On the other hand, when the second relay 354 is switched to closed, the voltage division ratio due to the combined resistance 350Z becomes relatively small, so the voltage at the other end 352b (feedback voltage Vf) becomes relatively large.

[0109] As described above, the boost IC 24 adjusts the boost voltage Vb so that the feedback voltage Vf input from the feedback terminal 24b becomes a predetermined value. Therefore, due to the voltage drop across the combined resistance 350Z, the first boost voltage Vb1 when the second relay 354 is open is greater than the second boost voltage Vb2 when the second relay 354 is closed.

[0110] The first resistor 351, the second resistor 352, and the third resistor 353 are set such that the first boost voltage Vb1 is greater than the rated voltage of battery 3, which is 12V, and the second boost voltage Vb2 is greater than or equal to the minimum voltage at which the electric motor 2 operates, but less than the rated voltage of battery 3. The operating voltage of the electric motor 2 is between DC 9V and DC 16V.

[0111] In this embodiment, the resistance value R41 of the first resistor 351 is set to 130kΩ, the resistance value R42 of the second resistor 352 is set to 68kΩ, and the resistance value R43 of the third resistor 353 is set to 20kΩ, so that the first boost voltage Vb1 becomes DC14V and the second boost voltage Vb2 becomes DC9.5V. The target voltage V0 of the feedback voltage Vf is set to DC1.274V.

[0112] To explain in more detail, when the second relay 354 is open, the voltage division ratio of the combined resistance 350Z and the third resistor 353 is 218:20, and the first boost voltage Vb1 when the feedback voltage Vf becomes the target voltage V0 can be calculated to be approximately 14V from the following equation (9).

[0113]

number

[0114] On the other hand, when the second relay 354 is closed, the voltage division ratio of the combined resistance 350Z and the third resistor 353 becomes 130:20, and the second boost voltage Vb2 when the feedback voltage Vf becomes the target voltage V0 can be calculated to be approximately 9.5V from the following equation (10).

[0115]

number

[0116] Therefore, by switching the second relay 354 between closed and open, the boost IC 24 controls the field-effect transistor 23 so that the feedback voltage Vf becomes the target voltage V0, thereby switching the voltage output from the backup power supply 6 to either the first boost voltage Vb1 or the second boost voltage Vb2 and boosting it.

[0117] In other words, the voltage divider circuit 350 includes a first resistor 351 with one end 351a connected to the output terminal 26b of the boost circuit 26, a second resistor 352 with one end 352a connected to the other end 351b of the first resistor 351 and the other end 352b connected to the feedback terminal 24b of the boost IC 24, and a third resistor 353 with one end 353a connected to the other end 352b of the second resistor 352 and the other end 353b grounded. The voltage divider changing circuit 356 includes a second relay 354. The second relay 354 is configured to be connected in parallel with the second resistor 352. When a predetermined boost condition is met, the second relay 354 is opened by the control unit 8, and the first resistor 351, the second resistor 352, and the third resistor 353 set the voltage divider changing circuit 356 such that when the second relay 354 is open, the first boost voltage Vb1 is greater than the rated voltage of the battery 3.

[0118] As a result, a voltage divider circuit 350 having a voltage divider changing circuit 356 can be constructed at low cost using the first resistor 351, the second resistor 352, the third resistor 353, and the second relay 354. Furthermore, the voltage division ratio can be easily changed using the second relay 354. In addition, regardless of whether the second relay 354 is closed or open, the first resistor 351, the second resistor 352, and the third resistor 353 are not connected in parallel with each other, so the combined resistance when connected in parallel does not need to be considered, making it easier to construct the circuit.

[0119] Alternatively, the second relay 354 may be connected in parallel to the first resistor 351 instead of the second resistor 352. In this case, by setting the resistance value R41 of the first resistor 351 to 68kΩ, the resistance value R42 of the second resistor 352 to 130kΩ, and the resistance value R43 of the third resistor 353 to 20kΩ, the first boost voltage Vb1 and the second boost voltage Vb2 according to the above embodiment can be realized. Specifically, when the second relay 354 is open, the voltage output from the backup power supply 6 can be boosted to the first boost voltage Vb1. When the second relay 354 is closed, the voltage output from the backup power supply 6 can be boosted to the second boost voltage Vb2.

[0120] Furthermore, the vehicle power supply device according to the present invention is not limited to the configuration of the above embodiment, and various modifications are possible.

[0121] In each of the above embodiments, a normally closed or normally open type relay is used depending on the closed / open state of the second relay when boosting to the first boost voltage Vb1, but the system is not limited to this. For example, in a configuration where the second relay is closed when boosting to the first boost voltage Vb1, a normally open type second relay may be used, and when boosting to the first boost voltage Vb1, the second relay may be controlled to close by a control signal from the control unit 8. Alternatively, a transistor may be used instead of the first relay and / or the second relay as switching elements.

[0122] In the above embodiment, the predetermined voltage boosting condition was defined as the condition that both the vehicle is not in a collision state and the battery 3 is functioning normally. However, instead, the predetermined voltage boosting condition may be determined to be met when at least one of the following conditions is met: the vehicle is not in a collision state and the battery 3 is functioning normally.

[0123] In the above embodiment, a vehicle power supply device that controls the power supply to a door latch device was described as an example, but it is not limited to this. It can be applied to any in-vehicle device that operates on power, such as an in-vehicle device equipped with an electric motor, and can be used to supply power to electric motors, solenoid valves, etc., used in power windows, electric tailgates, electric fuel lid caps, electric sliding doors, etc. [Explanation of Symbols]

[0124] 1. Vehicle power supply unit 2 Electric motor 3 Batteries 4 ECU 6. Backup power supply 7. Motor drive unit 8 Control Unit 9. 1st Relay 10 Door latch device 14 Door lock switch 20 Booster section 21 coils 22 diodes 23 Field-effect transistors 24 Boost ICs 25 Capacitors 26 Boost Circuit 31 1st power supply line 32 2nd power supply line 41. First control signal line 42 Second control signal line 43 Third control signal line 44. Fourth control signal line 50-volt voltage divider circuit 51 1st resistance 52 2nd resistor 53 3rd resistor 54. 2nd Relay 55 Switching Circuits 56. Voltage Divider Changing Circuit 81 Voltage Boost Condition Determination Unit 82 First Relay Control Unit 83 Door lock switch operation determination unit 84 Second Relay Control Unit 85 Boost IC Control Unit 86 Motor drive control unit

Claims

1. A backup power supply that is powered by the vehicle's battery, A boost unit that increases the voltage of the backup power supply to a boosted voltage, A motor drive unit connected to the battery and the voltage booster, which is powered by the higher voltage of the two and is capable of driving an electric motor, A control unit that controls the operation of the voltage boosting unit and Equipped with, The control unit is configured to receive at least one of a collision signal indicating that a vehicle has collided and a battery status signal capable of determining the state of the battery, and a predetermined voltage boosting condition is met when the control unit has not received the collision signal and when the control unit has determined, based on the battery status signal, that the battery is not in a faulty state or is not in a shut-off state, and when it has determined that the predetermined voltage boosting condition is met, the voltage boosting unit is controlled to boost the voltage of the backup power supply to a voltage greater than the rated voltage of the battery, a vehicle power supply device.

2. A backup power supply that is powered by a battery installed in the vehicle, A boost unit that increases the voltage of the backup power supply to a boosted voltage, A motor drive unit connected to the battery and the voltage booster, which is powered by the higher voltage of the two and is capable of driving an electric motor, A control unit that controls the operation of the voltage boosting unit and Equipped with, When the control unit determines that a predetermined voltage boosting condition has been met, it controls the voltage boosting unit to boost the voltage of the backup power supply to a voltage greater than the rated voltage of the battery. The aforementioned boosting unit is A boost circuit that increases the voltage of the backup power supply to the boosted voltage, A voltage divider circuit that divides the aforementioned boosted voltage and Equipped with, The boost circuit receives the voltage divided by the voltage divider circuit as a feedback voltage, and adjusts the boost voltage so that the feedback voltage becomes a predetermined voltage. The aforementioned voltage divider circuit includes a voltage divider changing circuit configured to change the voltage divider ratio. The aforementioned voltage divider circuit includes a resistor and a switching element connected in parallel with the resistor, in a vehicle power supply device.

3. When the control unit determines that the predetermined voltage boosting condition is not met, it controls the voltage boosting unit to raise the voltage of the backup power supply to a level lower than the rated voltage of the battery and higher than the minimum operating voltage of the electric motor. A vehicle power supply device according to claim 1 or 2.

4. The aforementioned boosting unit is A boost circuit that increases the voltage of the backup power supply to the boosted voltage, A voltage divider circuit that divides the aforementioned boosted voltage and Equipped with, The boost circuit receives the voltage divided by the voltage divider circuit as a feedback voltage, and adjusts the boost voltage so that the feedback voltage becomes a predetermined voltage. The voltage divider circuit includes a voltage divider changing circuit configured to change the voltage divider ratio. The vehicle power supply device according to claim 1.

5. The aforementioned voltage divider circuit is A first resistor, one end of which is connected to the output terminal of the boost circuit and the other end of which is connected to the input terminal of the boost circuit, A second resistor, one end of which is connected to the other end of the first resistor and the other end of which is grounded, It includes, The voltage divider circuit includes a switching circuit in which a third resistor and a switching element are connected in series, and the switching circuit is configured to be connected in parallel with the second resistor. The switching element is closed by the control unit when the predetermined voltage boosting condition is met. The first resistor, the second resistor, and the third resistor set the voltage divider circuit such that when the switching element is closed, the boosted voltage is greater than the rated voltage of the battery. The vehicle power supply device according to claim 2 or 4.

6. The aforementioned voltage divider circuit is A first resistor, one end of which is connected to the output terminal of the boost circuit and the other end of which is connected to the input terminal of the boost circuit, A second resistor, one end of which is connected to the other end of the first resistor and the other end of which is grounded, It includes, The voltage divider circuit includes a switching circuit in which a third resistor and a switching element are connected in series, and the switching circuit is configured to be connected in parallel with the first resistor. The switching element is opened by the control unit when the predetermined boosting condition is met. The first resistor, the second resistor, and the third resistor configure the voltage divider circuit such that when the switching element is open, the boosted voltage is greater than the rated voltage of the battery. The vehicle power supply device according to claim 2 or 4.

7. The aforementioned voltage divider circuit is A first resistor, one end of which is connected to the output terminal of the boost circuit and the other end of which is connected to the input terminal of the boost circuit, A second resistor, one end of which is connected to the other end of the first resistor, A third resistor is connected to the other end of the second resistor, with one end connected to the other end of the second resistor and the other end grounded. It includes, The voltage divider circuit includes a switching element, which is configured to be connected in parallel to either the second resistor or the third resistor. The switching element is closed by the control unit when the predetermined voltage boosting condition is met. The first resistor, the second resistor, and the third resistor set the voltage divider circuit such that when the switching element is closed, the boosted voltage is greater than the rated voltage of the battery. The vehicle power supply device according to claim 2 or 4.

8. The aforementioned voltage divider circuit is One end of the first resistor is connected to the output terminal of the boost circuit, A second resistor, one end of which is connected to the other end of the first resistor and the other end of which is connected to the input terminal of the boost circuit, A third resistor, one end of which is connected to the other end of the second resistor and the other end of which is grounded, It includes, The voltage divider circuit includes a switching element, and the switching element is configured to be connected in parallel to either the first resistor or the second resistor. The switching element is opened by the control unit when the predetermined voltage boosting condition is met. The first resistor, the second resistor, and the third resistor configure the voltage divider circuit such that when the switching element is open, the boosted voltage is greater than the rated voltage of the battery. The vehicle power supply device according to claim 2 or 4.

9. The control unit is configured to receive at least one of a collision signal indicating that a vehicle has collided and a battery status signal capable of determining the state of the battery. The predetermined voltage boosting condition is met when the control unit has not received the collision signal, and when the control unit has determined, based on the battery status signal, that the battery is not in a faulty state or a shut-off state. A vehicle power supply device according to claim 2, and any one of claims 3, 5 to 8 dependent on claim 2.

10. A vehicle power supply device according to any one of claims 1 to 9 above, A fork that can rotate between a latch position that engages with a striker on the vehicle body and an open position where the engagement is released, A claw that is rotatable between a locking position that holds the fork in the latch position and a release position that releases the hold, It has, The aforementioned claw is a door latch device in which the claw is rotationally driven by an electric motor powered by the vehicle's power supply unit.

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