Standby power supply device

Abstract

A backup power supply device including a control unit is provided. In a case where a main power source is normal at the time of start of an ignition device, the control unit controls to turn on or off a charging circuit to charge a capacitor from the main power source so that a voltage of the capacitor is constant at a target voltage, and to turn off a discharging circuit to stop discharging from the capacitor to a first electronic device. In a case where an abnormality occurs in the main power source at the time of start of the ignition device, the control unit turns off the charging circuit to stop charging the capacitor from the main power source, and turns on the discharging circuit to perform discharging from the capacitor to the first electronic device.

Description

Technical Field

[0001] This invention relates to a backup power supply device. Background Technology

[0002] Typically, vehicles, such as automobiles, include an onboard battery as their primary power source. In addition, vehicles include an alternator (generator) for charging the onboard battery. DC power is supplied by the primary power source to a large number of various electronic devices installed throughout the vehicle. These electronic devices in the vehicle are used to perform various functions continuously or as needed, such as driving, steering, stopping, door opening / closing, lighting, and communication, and all require a power supply.

[0003] On the other hand, for example, when components such as vehicle batteries, alternators, and wiring harnesses are damaged due to traffic accidents, power from the mains power supply is cut off, and power cannot be supplied to electronic devices from the mains power supply. To prevent the situation from worsening, it is desirable to continue supplying power to critical electronic devices even when power from the mains power supply is cut off. Therefore, a backup power supply is needed to replace the mains power supply.

[0004] Power supplies using double-layer capacitors or lithium-ion capacitors as backup power sources have been proposed (see Patent Document 1). Double-layer capacitors may degrade when the charge accumulation state persists. Lithium-ion capacitors may also degrade when they are in a fully charged state for extended periods.

[0005] Therefore, when the ignition device is off, consider discharging the double-layer capacitor or lithium-ion capacitor through a discharge resistor. However, the problem is that the charge accumulated in these capacitors is discharged in a wasteful manner.

[0006] Citation List

[0007] Patent documents

[0008] Patent document 1: JP-A-2020-182317. Summary of the Invention

[0009] The present invention was made in view of the above circumstances, and the object of the present invention is to provide a backup power supply device that effectively utilizes the charge accumulated in a capacitor.

[0010] To achieve the above objectives, the backup power supply device according to the present invention is characterized by the following features.

[0011] The backup power equipment includes

[0012] A capacitor, configured to supply power to a first electronic device and provided as a backup for the main power supply;

[0013] A charging circuit is disposed between the main power supply and the capacitor and is configured to connect and disconnect the charging from the main power supply to the capacitor.

[0014] A discharge circuit is disposed between the capacitor and the first electronic device and is configured to connect and disconnect the discharge from the capacitor to the first electronic device.

[0015] The control unit is configured to, when the main power supply is normal during ignition startup, control the connection or disconnection of the charging circuit to charge the capacitor from the main power supply, thereby maintaining the capacitor voltage at a target voltage, and disconnect the discharge circuit to stop the discharge from the capacitor to the first electronic device; and, in the event of an abnormality in the main power supply during ignition startup, disconnect the charging circuit to stop charging the capacitor from the main power supply and connect the discharge circuit to perform the discharge from the capacitor to the first electronic device; and

[0016] The first switch is located between the second electronic device and the capacitor.

[0017] After the ignition device is turned off, the control unit connects the discharge circuit and the first switch, and disconnects the charging circuit to perform the discharge from the capacitor to the second electronic device, and stops the charging from the main power supply to the capacitor.

[0018] According to the present invention, a backup power supply device that effectively utilizes the charge accumulated in a capacitor can be provided.

[0019] The invention has been briefly described above. Furthermore, the details of the invention will become clear from the following description, with reference to the accompanying drawings, of aspects for implementing the invention (hereinafter referred to as "embodiments"). Attached Figure Description

[0020] Figure 1 This is a circuit diagram illustrating an embodiment of a power supply system including a backup power supply device according to a first embodiment of the present invention.

[0021] Figure 2 It is shown Figure 1 The table shows the states of the charging circuit, the discharging circuit, and the first to third switches.

[0022] Figure 3 This is a circuit diagram illustrating an embodiment of a power supply system including a backup power supply device according to a second embodiment of the present invention.

[0023] Figure 4 It is shown Figure 3 A table showing the states of the charging circuit, the discharging circuit, and the first and second switches. Detailed Implementation

[0024] Specific embodiments of the present invention will now be described with reference to the accompanying drawings.

[0025] (First Embodiment)

[0026] First, refer to Figure 1 The description includes a power system 1 comprising a backup power supply device 3 according to a first embodiment. The power system 1 according to this embodiment is installed in a vehicle. Figure 1 As shown, the power system 1 according to the first embodiment includes a main battery 2 serving as the main power source, a backup power supply device 3 provided for the backup main battery 2, a first electronic device 4, and a second electronic device 5 different from the first electronic device 4. The first electronic device 4 and the second electronic device 5 are powered by the main battery 2 and the backup power supply device 3.

[0027] The main battery 2 supplies power to the first electronic device 4 and the second electronic device 5. The first electronic device 4 is operated when power is supplied during ignition activation, and it is unnecessary to operate when power is cut off during ignition deactivation. The first electronic device 4 is an important device, and it is desirable to continue supplying power to it even if an malfunction occurs in the main battery 2 due to an accident or other reasons, preventing power supply from the main battery 2.

[0028] The second electronic device 5 includes a communication device for communicating with terminals such as smartphones, lighting equipment, and air purifiers. It is desirable to supply power to the second electronic device 5 and operate it for a period of time not only when the ignition device is activated but also after the ignition device is deactivated.

[0029] Next, the backup power supply device 3 will be described. The backup power supply device 3 includes a double-layer capacitor 31 serving as a capacitor, a charging circuit 32, a discharging circuit 33, conductive paths R1 and R2, a discharge resistor 34, first to third switches S1 to S3, and a control unit 35. The double-layer capacitor 31 is provided as a backup for the main battery 2. When the state of accumulated charge persists, the double-layer capacitor 31 deteriorates. Therefore, when the ignition device is activated, the double-layer capacitor 31 is fully charged so that the voltage reaches the target voltage, thereby preparing for any abnormal situation in the main battery 2, and when the ignition device is deactivated, the double-layer capacitor 31 is discharged until the voltage becomes zero to prevent deterioration.

[0030] A charging circuit 32 is disposed between the positive terminal of the main battery 2 and one end of the double-layer capacitor 31. The negative terminal of the main battery 2 and the other end of the double-layer capacitor 31 are grounded. The charging circuit 32 can switch on and off the charging (power supply) from the main battery 2 to the double-layer capacitor 31. For example, the charging circuit 32 includes a DC / DC converter and a switch. When the voltage of the main battery 2 is higher or lower than the voltage of the double-layer capacitor 31, the DC / DC converter lowers or raises the power supply voltage of the main battery 2 and supplies the lowered or reduced power supply voltage to the double-layer capacitor 31. The switch switches on or off the power supply from the main battery 2 to the DC / DC converter (the DC / DC converter and switch are not shown). When the voltages of the main battery 2 and the double-layer capacitor 31 are substantially equal, the charging circuit 32 only includes a switch (not shown). By switching on or off the switch disposed in the charging circuit 32, the charging from the main battery 2 to the double-layer capacitor 31 can be switched on or off.

[0031] A discharge circuit 33 is disposed between one end of the double-layer capacitor 31 and the first electronic device 4. The discharge circuit 33 can switch the discharge (power supply) from the double-layer capacitor 31 to the first electronic device 4 on and off. For example, the discharge circuit 33 includes a DC / DC converter and a switch. When the voltage supplied to the first electronic device 4 is higher or lower than the voltage of the double-layer capacitor 31, the DC / DC converter lowers or raises the voltage of the double-layer capacitor 31 and supplies the lowered or raised voltage to the first electronic device 4. The switch switches the power supply from the double-layer capacitor 31 to the DC / DC converter (the DC / DC converter and switch are not shown). When the voltages of the double-layer capacitor 31 and the first electronic device 4 are substantially equal, the discharge circuit 33 only includes a switch. By switching the switch disposed in the discharge circuit 33, the discharge from the double-layer capacitor 31 to the first electronic device 4 can be switched on or off. The charging circuit 32 and the discharge circuit 33 described above are controlled by a control unit 35, which will be described later.

[0032] Conductive path R1 is connected to the positive terminal of the main battery 2 and the first electronic device 4, and bypasses the charging circuit 32 and the discharging circuit 33. Conductive path R2 is connected to the positive terminal of the main battery 2 and the second electronic device 5, and bypasses the charging circuit 32 and the discharging circuit 33. Discharging resistor 34 is connected in parallel with double-layer capacitor 31 between charging circuit 32 and discharging circuit 33. One end of discharge resistor 34 is connected to one end of double-layer capacitor 31 via a third switch S3, which will be described later, and the other end of discharge resistor 34 is grounded.

[0033] A first switch S1 is disposed between the second electronic device 5 and the double-layer capacitor 31. In this embodiment, the first switch S1 is positioned closer to the second electronic device 5 than the connection point between the discharge circuit 33 and the first electronic device 4. When the first switch S1 is turned on, discharge can be made from the double-layer capacitor 31 to the second electronic device 5, and when the first switch S1 is turned off, the discharge from the double-layer capacitor 31 to the second electronic device 5 is cut off.

[0034] The second switch S2 is disposed on the conductive path R2 connecting the second electronic device 5 and the main battery 2, and is connected in parallel with the first switch S1. When the second switch S2 is turned on, power can be supplied from the main battery 2 to the second electronic device 5, and when the second switch S2 is turned off, the power supply from the main battery 2 to the second electronic device 5 is cut off.

[0035] The third switch S3 is disposed on the discharge path from the double-layer capacitor 31 to the discharge resistor 34. In this embodiment, the third switch S3 is connected between one end of the double-layer capacitor 31 and the discharge resistor 34. More specifically, the double-layer capacitor 31, the series-connected discharge resistor 34, and the third switch S3 are connected in parallel between the connection point of the charging circuit 32 and the discharging circuit 33 and ground. When the third switch S3 is turned on, the double-layer capacitor 31 discharges through the discharge resistor 34, and when the third switch S3 is turned off, the discharge from the double-layer capacitor 31 to the discharge resistor 34 is cut off. The first to third switches S1 to S3 are controlled to be turned on and off by the control unit 35, which will be described later.

[0036] The control unit 35 is connected to the charging circuit 32, the discharging circuit 33, and the aforementioned first to third switches S1 to S3, and controls the on / off state of the switches (not shown) included in the charging circuit 32 and the discharging circuit 33, as well as the first to third switches S1 to S3. The control unit 35 includes, for example, a microcomputer (not shown). The microcomputer includes a memory storing programs and a central processing unit (CPU) that runs according to the programs.

[0037] Next, we will refer to Figure 2 The operation of the power system 1 with the above configuration is described. In the power system 1 according to this embodiment, the user can preset whether the second electronic device 5 is used for a period of time after the ignition device is turned off or is not used after the ignition device is turned off. For example, the input unit of a navigation device or communication with a smartphone can be used to make such a setting. The setting content can be stored in the memory of the control unit 35. That is, the control unit 35 also serves as a storage unit.

[0038] Immediately after the ignition is turned off, the control unit 35 determines whether the second electronic device 5 is configured to operate for a period of time after the ignition is turned off. For example... Figure 2As shown in (A), when the second electronic device 5 is set to be used for a period of time after the ignition device is turned off, the control unit 35 turns on the switch in the discharge circuit 33 and the first switch S1, and turns off the switch in the charging circuit 32 and the second and third switches S2 and S3.

[0039] As a result, the charging of the main battery 2 to the double-layer capacitor 31 and the power supply to the second electronic device 5 are cut off, and the double-layer capacitor 31 is discharged through the second electronic device 5. When the ignition device is turned off, the discharge from the double-layer capacitor 31 to the first electronic device 4 is prohibited because the switch built into the first electronic device 4 is turned off.

[0040] On the other hand, when the second electronic device 5 is set to not be used after the ignition device is turned off, the control unit 35 turns on the third switch S3 and disconnects the switches in the charging circuit 32 and the discharging circuit 33, as well as the first and second switches S1 and S2, as shown below. Figure 2 As shown in (B), the charging from the main battery 2 to the double-layer capacitor 31 is cut off. With the discharge (power supply) from the main battery 2 and the double-layer capacitor 31 to the second electronic device 5 cut off, no power is supplied to the second electronic device 5, and the second electronic device 5 is not used. The double-layer capacitor 31 is discharged through the discharge resistor 34.

[0041] The control unit 35 detects the voltage of the double-layer capacitor 31, which is discharged through the second electronic device 5 or the discharge resistor 34. When the control unit 35 determines that the charge has become zero (i.e., the double-layer capacitor 31 has entered the end-of-discharge state), the control unit 35 disconnects the switches in the charging circuit 32 and the discharging circuit 33, as well as the first to third switches S1 to S3. Figure 2 As shown in (C). That is, when the second electronic device 5 is configured to be used after the ignition device is turned off, power is supplied to the second electronic device 5 until the charge of the double-layer capacitor 31 becomes zero.

[0042] When the ignition device is activated and the main battery 2 is in a normal state without any abnormalities, the control unit 35 repeatedly switches the switch in the charging circuit 32 on and off, such as... Figure 2 As shown in (D). More specifically, the control unit 35 detects the voltage of the double-layer capacitor 31, and when the detected voltage reaches the target voltage, the control unit 35 disconnects the charging circuit 32 to cut off the charging from the main battery 2 to the double-layer capacitor 31. When natural discharge is performed and the detected voltage of the double-layer capacitor 31 drops below the target voltage, the control unit 35 turns on the charging circuit 32 to charge the double-layer capacitor 31 from the main battery 2.

[0043] like Figure 2As shown in (D), the control unit 35 turns on the second switch S2 and turns off the switches in the discharge circuit 33, the first switch S1, and the third switch S3. As a result, the second electronic device 5 is operated by receiving power from the main battery 2, and the discharge from the double-layer capacitor 31 to the discharge resistor 34 or the second electronic device 5 is cut off. When the ignition device is started, power is supplied from the main battery 2 to the first electronic device 4 via the conductive path R1 because the switch built into the first electronic device 4 is turned on.

[0044] like Figure 2 As shown in (E), when the ignition device is activated and an abnormality occurs in the main battery 2, the control unit 35 turns on the switch in the discharge circuit 33 and turns off the switch in the charging circuit 32 as well as the first to third switches S1 to S3. As a result, power can be supplied from the double-layer capacitor 31 to the first electronic device 4, and the power supply to the first electronic device 4 can continue even after an abnormality occurs in the main battery 2. Furthermore, the charging from the main battery 2 to the double-layer capacitor 31 and the power supply from the main battery 2 and the double-layer capacitor 31 to the second electronic device 5 are cut off.

[0045] According to the first embodiment described above, after the ignition device is turned off, the control unit 35 turns on the switch in the discharge circuit 33 and the first switch S1, and turns off the switch in the charging circuit 32 to perform the discharge from the double-layer capacitor 31 to the second electronic device 5, and stops the charging from the main battery 2 to the double-layer capacitor 31. As a result, after the ignition device is turned off, the double-layer capacitor 31 can discharge to prevent deterioration, and the discharge energy of the double-layer capacitor 31 can be effectively used as the power source for the second electronic device 5.

[0046] According to the first embodiment described above, when the main battery 2 is in a normal state during ignition device startup, the control unit 35 can turn on the second switch S2 to supply power from the main battery 2 to the second electronic device 5. In the event of an abnormality in the main battery 2 during ignition device startup, after the ignition device is turned off, the control unit 35 disconnects the second switch S2 to cut off the power supply from the main battery 2 to the second electronic device 5, but does not cut off the discharge from the double-layer capacitor 31 to the second electronic device 5.

[0047] According to the first embodiment described above, after the ignition device is turned off and the charge on the double-layer capacitor 31 becomes zero, the control unit 35 disconnects the second switch S2 to cut off the power supply from the main battery 2 to the second electronic device 5. As a result, after the ignition device is turned off, the second electronic device 5 can be driven continuously for a period of time until the charge on the double-layer capacitor 31 becomes zero.

[0048] According to the first embodiment described above, after the ignition device is turned off, when the second electronic device 5 is set to be used, the control unit 35 turns on the first switch S1 and turns off the third switch S3. After the ignition device is turned off, when the second electronic device 5 is set to be unused, the control unit 35 turns off the second switch S2 and turns on the third switch S3. As a result, even when the second electronic device 5 is set to be unused, the double-layer capacitor 31 can be discharged.

[0049] Although the double-layer capacitor 31 is used as a capacitor in the first embodiment described above, the present invention is not limited thereto. A lithium-ion capacitor can be used instead of the double-layer capacitor 31. In this case, when the voltage of the lithium-ion capacitor reaches a specified value, the control unit 35 determines that the lithium-ion capacitor has entered the discharge end state.

[0050] Although in the first embodiment described above, the user can set whether the second electronic device 5 is used after the ignition device is turned off, the present invention is not limited thereto. Alternatively, the second electronic device 5 can be used continuously after the ignition device is turned off, and the discharge resistor 34 and the third switch S3 are not required.

[0051] (Second Embodiment)

[0052] Next, we will refer to Figure 3 A power supply system 1B according to a second embodiment is described. Figure 3 In, as described above in the first embodiment Figure 1 The same components of the power system 1 shown are indicated by the same reference numerals, and their detailed descriptions will be omitted. Figure 3 As shown, the power system 1B according to the second embodiment includes a main battery 2, a backup power supply device 3B provided for the backup main battery 2, and a first electronic device 4 and a second electronic device 5B supplied with power from the main battery 2 and the backup power supply device 3B.

[0053] The main battery 2 supplies power to the first electronic device 4 and the second electronic device 5B. Since the first electronic device 4 is the same as the first electronic device according to the first embodiment, its detailed description will be omitted here. The second electronic device 5B is a device such as a clock, smart key, or memory. It is desirable to continuously supply power to the second electronic device 5B and operate the second electronic device 5B from when the ignition device is off until when the ignition device is on.

[0054] Next, the backup power supply device 3B will be described. The backup power supply device 3B includes a small lithium-ion capacitor 31B acting as a capacitor, a charging circuit 32B, a discharging circuit 33B, first and second switches S1B and S2B, a conductive path R3, a conductive path R4, and a control unit 35B. When fully charged, the small lithium-ion capacitor 31B degrades. Therefore, when the ignition device is activated, the small lithium-ion capacitor 31B is fully charged so that its voltage reaches the target voltage in preparation for any abnormality in the main battery 2, and when the ignition device is deactivated, the small lithium-ion capacitor 31B is discharged until its voltage drops below a specified value below the target voltage to prevent degradation.

[0055] Charging circuit 32B is disposed between the positive terminal of main battery 2 and one end of small lithium-ion capacitor 31B. The negative terminal of main battery 2 and the other end of small lithium-ion capacitor 31B are grounded. Charging circuit 32B can connect and disconnect the charging (power supply) from main battery 2 to small lithium-ion capacitor 31B.

[0056] A discharge circuit 33B is disposed between one end of a small lithium-ion capacitor 31B and the first electronic device 4. The discharge circuit 33B can connect and disconnect the discharge (power supply) from the small lithium-ion capacitor 31B to the first electronic device 4. Since the configuration of the charging circuit 32B and the discharge circuit 33B is the same as that of the charging circuit 32 and the discharge circuit 33 according to the first embodiment, their detailed description will be omitted here.

[0057] Conductive path R3 connects to the positive terminal of the first electronic device 4 and the main battery 2, and bypasses the charging circuit 32B and the discharging circuit 33B. Conductive path R4 connects the connection point of the discharging circuit 33B and the first electronic device 4, and the second electronic device 5B. The second electronic device 5B is connected between the charging circuit 32B and the main battery 2.

[0058] A first switch S1B is disposed between the second electronic device 5B and the small lithium-ion capacitor 31B. More specifically, a conductive path R4 connects the discharge circuit 33B to the connection point of the first electronic device 4 and the second electronic device 5B. The small lithium-ion capacitor 31B is connected to the second electronic device 5B via the discharge circuit 33B and the conductive path R4. The first switch S1B is disposed on the conductive path R4. When the first switch S1B is closed, power is supplied from the small lithium-ion capacitor 31B to the second electronic device 5B; when the first switch S1B is open, the power supply from the small lithium-ion capacitor 31B to the second electronic device 5B is cut off.

[0059] The second switch S2B is located between the second electronic device 5B and the main battery 2. When the second switch S2B is turned on, power is supplied from the main battery 2 to the first electronic device 4 and the second electronic device 5B, and when the second switch S2B is turned off, the power supply from the main battery 2 to the first electronic device 4 and the second electronic device 5B is cut off.

[0060] Next, we will refer to Figure 4 The operation of the power system 1B with the above configuration is described. Immediately after the ignition device is turned off, the control unit 35B turns on the switch and the first switch S1B in the discharge circuit 33B, and turns off the switch and the second switch S2B in the charging circuit 32B, as follows. Figure 4 As shown in (A).

[0061] Therefore, the charging of the main battery 2 to the small lithium-ion capacitor 31B and the power supply to the first electronic device 4 and the second electronic device 5B are cut off, and the discharge from the small lithium-ion capacitor 31B to the second electronic device 5B is performed. When the ignition device is turned off, the discharge from the small lithium-ion capacitor 31B to the first electronic device 4 is not performed because the built-in switch in the first electronic device 4 is open.

[0062] Subsequently, when the small lithium-ion capacitor 31B discharges and its voltage reaches a specified value (the small lithium-ion capacitor 31B enters the end-of-discharge state), the control unit 35B turns on the second switch S2B and disconnects the switches in the charging circuit 32B and the discharging circuit 33B, as well as the first switch S1B. Figure 4 As shown in (B). As a result, power continues to be supplied from the main battery 2 to the second electronic device 5B.

[0063] On the other hand, when the ignition device is activated and the main battery 2 is in a normal state without any abnormalities, the control unit 35B repeatedly turns the switch in the charging circuit 32B on and off, such as... Figure 4 As shown in (C). Specifically, the control unit 35B detects the voltage of the small lithium-ion capacitor 31B, and when the detected voltage reaches the target voltage, the control unit 35B disconnects the charging circuit 32B to cut off the charging from the main battery 2 to the small lithium-ion capacitor 31B. On the other hand, when natural discharge is performed and the detected voltage drops below the target voltage, the control unit 35B turns on the charging circuit 32B to charge the small lithium-ion capacitor 31B from the main battery 2.

[0064] like Figure 4As shown in (C), the control unit 35B turns on the second switch S2B and turns off the switch in the discharge circuit 33B and the first switch S1B. As a result, the second electronic device 5B operates by receiving power from the main battery 2, and the discharge from the small lithium-ion capacitor 31B to the second electronic device 5B is cut off. When the ignition device is started, power is supplied from the main battery 2 to the first electronic device 4 because the switch built into the first electronic device 4 is turned on.

[0065] like Figure 4 As shown in (D), when the ignition device is activated and an abnormality occurs in the main battery 2, the control unit 35B turns on the switch in the discharge circuit 33b and turns off the switch in the charging circuit 32b, as well as the first and second switches S1B and S2B. As a result, power can be supplied from the small lithium-ion capacitor 31 to the first electronic device 4, and the power supply to the first electronic device 4 can continue even after an abnormality occurs in the main battery 2. Furthermore, the charging from the main battery 2 to the small lithium-ion capacitor 31B and the power supply to the second electronic device 5B are cut off.

[0066] According to the second embodiment described above, after the ignition device is turned off, the control unit 35B turns on the switch in the discharge circuit 33B and the first switch S1B, and turns off the switch in the charging circuit 32B to perform the discharge from the small lithium-ion capacitor 31B to the second electronic device 5B, and stops the charging from the main battery 2 to the small lithium-ion capacitor 31B. As a result, after the ignition device is turned off, the small lithium-ion capacitor 31B can discharge to prevent degradation, and the discharge energy of the small lithium-ion capacitor 31B can be effectively used as the power supply for the second electronic device 5B.

[0067] According to the second embodiment described above, when the main battery 2 is in a normal state during ignition device startup, the control unit 35B can turn on the second switch S2B to supply power from the main battery 2 to the second electronic device 5B. In the event of an abnormality in the main battery 2 during ignition device startup, after the ignition device is turned off, the control unit 35B disconnects the second switch S2B to cut off the power supply from the main battery 2 to the second electronic device 5B, without cutting off the discharge from the small lithium-ion capacitor 31B to the second electronic device 5B.

[0068] According to the second embodiment described above, after the ignition device is turned off and the voltage of the small lithium-ion capacitor 31B reaches a specified value, the control unit 35B turns on the second switch S2B to supply power from the main battery 2 to the second electronic device 5B. As a result, even after the voltage of the small lithium-ion capacitor 31B reaches the specified value, the second electronic device 5B can still be driven after the ignition device is turned off.

[0069] Although a small lithium-ion capacitor 31B is used as the capacitor in the second embodiment described above, the present invention is not limited thereto. A double-layer capacitor can be used instead of the small lithium-ion capacitor 31B. In this case, when the charge of the double-layer capacitor becomes zero, the control unit 35B determines that the double-layer capacitor has entered the discharge end state.

[0070] This invention is not limited to the above embodiments, and can be appropriately modified and improved. Furthermore, the material, shape, size, quantity, and arrangement of the elements in the above embodiments are optional and not limited, as long as the purpose of this invention can be achieved.

[0071] Here, the features of the embodiments of the backup power supply device according to the present invention described above will be briefly summarized and listed in [1] to [6] below.

[0072] [1] A backup power supply device (3, 3B) comprising:

[0073] Capacitors (31, 31B) are provided as a backup for the main power source (2) that supplies power to the first electronic device (4);

[0074] A charging circuit (32, 32B) is disposed between the main power supply (2) and the capacitor (31, 31B) and is configured to turn on and off the charging from the main power supply (2) to the capacitor (31, 31B);

[0075] A discharge circuit (33, 33B) is disposed between the capacitor (31, 31B) and the first electronic device (4), and is configured to turn on and off the discharge from the capacitor (31, 31B) to the first electronic device (4).

[0076] The control unit (35, 35B), when the main power supply (2) is normal during ignition device startup, controls the connection or disconnection of the charging circuit (32, 32B) to charge the capacitor (31, 31B) from the main power supply (2) so that the voltage of the capacitor (31, 31B) is constant at a target voltage, and disconnects the discharge circuit (33, 33B) to stop the discharge from the capacitor (31, 31B) to the first electronic device (4), and, in the event of an abnormality in the main power supply (2) during ignition device startup, disconnects the charging circuit (32, 32B) to stop the charging from the main power supply (2) to the capacitor (31, 31B), and connects the discharge circuit (33, 33B) to perform the discharge from the capacitor (31, 31B) to the first electronic device (4); and

[0077] A first switch (S1, S1B) is disposed between the second electronic device (5, 5B) and the capacitor (31, 31B), wherein

[0078] After the ignition device is turned off, the control unit (35, 35B) connects the discharge circuit (33, 33B) and the first switch (S1, S1B) and disconnects the charging circuit (32, 32B) to perform the discharge from the capacitor (31, 31B) to the second electronic device (5, 5B) and stop the charging from the main power supply (2) to the capacitor (31, 31B).

[0079] According to the above configuration [1], after the ignition device is turned off, the capacitors (31, 31B) can be discharged to prevent deterioration, and the discharge energy of the capacitors (31, 31B) can be effectively used as the power supply for the second electronic device (5, 5B).

[0080] [2] The backup power supply equipment (3, 3B) according to [1] further includes:

[0081] The second switch (S2, S2B) is disposed between the second electronic device (5, 5B) and the main power supply (2), wherein

[0082] When the main power supply (2) is normal during ignition device startup, the control unit (35, 35B) turns on the second switch (S2, S2B) to supply power from the main power supply (2) to the second electronic device (5, 5B). In the event of an abnormality in the main power supply (2) during ignition device startup, the control unit (35, 35B) disconnects the second switch (S2, S2B) after the ignition device is turned off to cut off the power supply from the main power supply (2) to the second electronic device (5, 5B).

[0083] According to the configuration described above [2], under normal conditions when the main power supply (2) is normal during ignition device startup, the control unit (35, 35B) can turn on the second switch (S2, S2B) to supply power from the main power supply (2) to the second electronic device (5, 5B). In the event of an abnormality in the main power supply (2) during ignition device startup, after the ignition device is turned off, the control unit (35, 35B) disconnects the second switch (S2, S2B) to cut off the power supply from the main power supply (2) to the second electronic device (5, 5B), but does not cut off the discharge from the capacitor (31, 31B) to the second electronic device (5, 5B).

[0084] [3] According to the backup power supply device (3) described in [2], wherein

[0085] After the ignition device is turned off and the capacitor (31) enters the discharge end state, the control unit (35) disconnects the second switch (S2) and continuously cuts off the power supply from the main power supply (2) to the second electronic device (5).

[0086] According to the configuration described above [3], after the ignition device is turned off and the capacitor (31) enters the end-of-discharge state, the control unit (35) disconnects the second switch (S2) to cut off the power supply from the main power supply (2) to the second electronic device (5). As a result, after the ignition device is turned off, the second electronic device (5) can be driven for a period of time until the capacitor 31 enters the end-of-discharge state.

[0087] [4] According to the backup power supply device (3B) described in [2], wherein

[0088] After the ignition device is turned off and the capacitor (31B) enters the end-of-discharge state, the control unit (35B) turns on the second switch (S2B) to start supplying power from the main power supply (2) to the second electronic device (5B).

[0089] According to the configuration described above [4], after the ignition device is turned off and the capacitor (31B) enters the end-of-discharge state, the control unit (35B) turns on the second switch (S2B) to supply power from the main power supply (2) to the second electronic device (5B). As a result, even after the capacitor (31B) enters the end-of-discharge state, the second electronic device (5B) can be driven after the ignition device is turned off.

[0090] [5] The backup power supply device (3) according to [3] further includes:

[0091] A discharge resistor (34) is configured to discharge the capacitor (31);

[0092] A third switch (S3) is disposed between the capacitor (31) and the discharge resistor (34); and

[0093] Storage unit (35) stores settings regarding whether to use the second electronic device (5) after the ignition device is turned off, wherein

[0094] When the second electronic device (5) is set to be used, the control unit (35) turns on the first switch (S1) and turns off the third switch (S3) after the ignition device is turned off; and when the second electronic device (5) is set to be unused, the control unit (35) turns off the second switch (S2) and turns on the third switch (S3) after the ignition device is turned off.

[0095] According to the configuration described above [5], when the second electronic device (5) is set to be used, the control unit (35) turns on the first switch (S1) and turns off the third switch (S3) after the ignition device is turned off, and when the second electronic device (5) is set to be unused, the control unit (35) turns off the second switch (S2) and turns on the third switch (S3) after the ignition device is turned off. As a result, the capacitor (31) can discharge even when the second electronic device (5) is set to be unused.

[0096] [6] The backup power supply device (3, 3B) according to any one of [1] to [5], wherein

[0097] The capacitor is formed from one of an electric double-layer capacitor (31) and a lithium-ion capacitor (31B).

[0098] According to the configuration described above [6], double-layer capacitors (31) and lithium-ion capacitors (31B) can be used effectively.

Claims

1. A backup power supply device, comprising: A capacitor, configured to supply power to a first electronic device and provided as a backup for the main power supply; A charging circuit is disposed between the main power supply and the capacitor, and is configured to connect and disconnect the charging from the main power supply to the capacitor; A discharge circuit is disposed between the capacitor and the first electronic device and is configured to connect and disconnect the discharge from the capacitor to the first electronic device; The control unit is configured to, when the main power supply is normal during ignition activation, control the connection or disconnection of the charging circuit to charge the capacitor with the main power supply so that the voltage of the capacitor is constant at a target voltage, and disconnect the discharge circuit to stop the discharge from the capacitor to the first electronic device; and when an abnormality occurs in the main power supply during ignition activation, disconnect the charging circuit to stop the charging from the main power supply to the capacitor, and connect the discharge circuit to perform the discharge from the capacitor to the first electronic device. A first switch is disposed between the second electronic device and the capacitor; A second switch is disposed between the second electronic device and the main power supply; A discharge resistor configured to discharge the capacitor; A third switch is disposed between the capacitor and the discharge resistor; and A storage unit that stores settings regarding whether to use the second electronic device after the ignition device is turned off. After the ignition device is turned off, the control unit connects the discharge circuit and the first switch, and disconnects the charging circuit to perform discharge from the capacitor to the second electronic device, and stops charging from the main power supply to the capacitor. Specifically, when the main power supply is normal during ignition device startup, the control unit turns on the second switch to supply power from the main power supply to the second electronic device. Conversely, if an abnormality occurs in the main power supply during ignition device startup, the control unit disconnects the second switch after the ignition device is turned off to cut off the power supply from the main power supply to the second electronic device. Specifically, after the ignition device is turned off and the capacitor enters the end-of-discharge state, the control unit disconnects the second switch and continues to cut off the power supply from the main power source to the second electronic device. Specifically, when the second electronic device is set to be used, the control unit turns on the first switch and turns off the third switch after the ignition device is turned off; and when the second electronic device is set to be unused, the control unit turns off the second switch and turns on the third switch after the ignition device is turned off.

2. The backup power supply equipment according to claim 1, in, After the ignition device is turned off and the capacitor enters the end-of-discharge state, the control unit turns on the second switch to start supplying power from the main power supply to the second electronic device.

3. The backup power supply equipment according to claim 1 or 2, in, The capacitor is composed of either an electric double-layer capacitor or a lithium-ion capacitor.

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