Circuit device

Abstract

In a power supply control device (11), when the connection of the storage battery (10) is normally connected, when the bypass switch (25) is disconnected, current flows in the first switching circuit (21) and the diode (24) in sequence. When the connection of the storage battery (10) is normally connected, when the output voltage of the storage battery (10) is lower than a reference voltage, the second switching circuit (22) switches the bypass switch (25) from disconnected to connected.

Description

Technical Field

[0001] The present disclosure relates to a circuit device.

[0002] This application claims the priority based on Japanese application No. 2018-139769 for which it applied on July 25, 2018, and cites all the contents described in the said Japanese application. Background Art

[0003] Patent Document 1 discloses a circuit device for a vehicle having an electric circuit. In the circuit device, the cathode of a diode is connected to the electric circuit. When the positive electrode of a battery is connected to the anode of the diode, power is supplied from the battery to the electric circuit via the diode, and the electric circuit operates.

[0004] When the negative electrode of the battery is connected to the anode of the diode by mistake, the diode prevents current from flowing from the battery to the electrical circuit, so that a voltage with an incorrect polarity is not applied to the electrical circuit.

[0005] Prior art literature

[0006] Patent Literature

[0007] Patent Document 1: Japanese Patent Application Publication No. 2011-225043 Summary of the invention

[0008] A circuit device according to one embodiment of the present disclosure includes an electrical circuit to which power is supplied when a DC voltage is applied between two terminals, wherein the circuit device includes: a diode arranged in a supply path for supplying power to the electrical circuit, a switch connected between the two ends of the diode, and a switching circuit that switches the switch from off to on when the DC voltage is applied in a specific direction and the DC voltage is lower than a predetermined voltage, wherein when the DC voltage is applied in the specific direction, when the switch is off, current flows sequentially in the electrical circuit and the diode. BRIEF DESCRIPTION OF THE DRAWINGS

[0009] Figure 1 This is a block diagram showing a main part configuration of a power supply system in the first embodiment.

[0010] Figure 2 is a circuit diagram of a second switching circuit.

[0011] Figure 3 It is a timing chart for explaining the operation of the second switching circuit.

[0012] Figure 4 This is a diagram for explaining the effect of the power supply control device.

[0013] Figure 5 This is a circuit diagram of a second switching circuit in the second embodiment.

[0014] Figure 6 This is a block diagram showing a main part configuration of a power supply system in the third embodiment.

[0015] Figure 7 This is a block diagram showing a main part configuration of a power supply system in the fifth embodiment. DETAILED DESCRIPTION

[0016] [Problems to be Solved by the Present Disclosure]

[0017] When current flows through a diode, a voltage drop occurs in the diode. Therefore, when power is supplied from a battery to an electrical circuit via a diode, the voltage applied to the electrical circuit is lower than the output voltage of the battery. Generally, the output voltage of a battery mounted on a vehicle is not constant but fluctuates. When the output voltage of the battery drops, the voltage applied to the electrical circuit also drops.

[0018] In the circuit device described in Patent Document 1, when the output voltage of the battery drops, there is a high possibility that the voltage applied to the electric circuit is lower than the operating voltage required for the operation of the electric circuit. When the voltage applied to the electric circuit is lower than the operating voltage, the electric circuit suddenly stops operating.

[0019] Therefore, an object of the present invention is to provide a circuit device in which the possibility of an electrical circuit suddenly stopping operation is low.

[0020] [Effects of the present disclosure]

[0021] According to the present disclosure, the possibility of the electrical circuit suddenly stopping operation is low.

[0022] [Description of Embodiments of the Present Disclosure]

[0023] First, the embodiments of the present disclosure will be described by way of examples. At least a part of the embodiments described below may be arbitrarily combined.

[0024] (1) A circuit device according to one embodiment of the present invention includes an electrical circuit to which power is supplied when a DC voltage is applied between two terminals, wherein the circuit device includes: a diode arranged in a supply path for supplying power to the electrical circuit, a switch connected between the two ends of the diode, and a switching circuit that switches the switch from off to on when the DC voltage is applied in a specific direction and the DC voltage is lower than a predetermined voltage, wherein when the DC voltage is applied in the specific direction, when the switch is off, current flows sequentially in the electrical circuit and the diode.

[0025] In one of the above-mentioned modes, when a DC voltage is applied in a direction different from the specific direction, when the switch is turned off, the current does not flow in the electrical circuit due to the action of the diode. Therefore, it is possible to prevent a voltage with an incorrect polarity from being applied to the electrical circuit. When a DC voltage is applied in a specific direction, when the switch is turned off, the current flows in the electrical circuit and the diode in sequence, and a voltage drop occurs at the diode. In the same case, when the switch is turned on, the current flows in the electrical circuit and the switch in sequence, and no voltage drop occurs at the diode.

[0026] When a DC voltage is applied in a specific direction, when the DC voltage is lower than a predetermined voltage, the switch is switched from off to on, and the voltage applied to the electrical circuit increases. Therefore, the possibility that the voltage applied to the electrical circuit is lower than the operating voltage required for the operation of the electrical circuit and the operation of the electrical circuit stops is low.

[0027] (2) In a circuit device of one embodiment of the present invention, the switch is a transistor, and the switch has a first end configured on the anode side of the diode in the supply path, a second end configured on the cathode side of the diode in the supply path, and a third end, when the voltage of the third end increases, the resistance value between the first end and the second end decreases, and the switching circuit switches the switch from off to on by increasing the voltage of the third end.

[0028] In the above embodiment, the switch is an N-channel FET (Field Effect Transistor) or an NPN bipolar transistor, etc. The switching circuit switches the switch from off to on by increasing the voltage of a third terminal corresponding to a gate or a base.

[0029] (3) In the circuit device according to one aspect of the present disclosure, the switch is an N-channel FET, and the diode is a parasitic diode of the switch.

[0030] In the above-mentioned embodiment, the switch is an N-channel FET, and the parasitic diode of the switch is used as the diode disposed in the supply path, so the manufacturing cost is low.

[0031] (4) In a circuit device of one embodiment of the present invention, the switching circuit comprises: a resistor having one end connected to the third end of the switch, and a second switch having one end connected to the third end of the switch, and when the DC voltage is applied in the specific direction, a positive voltage is applied to the other end of the resistor based on the potential of the other end of the second switch, and when the DC voltage is applied in the specific direction, the second switch switches from on to off when the DC voltage is lower than a predetermined voltage.

[0032] In the above-mentioned one mode, when the second switch is on, the voltage applied to the third terminal of the switch is low, so the switch is off. When a DC voltage is applied in a specific direction, when the DC voltage is lower than a predetermined voltage, the second switch is switched off. At this time, the voltage at the third terminal of the switch rises to a high voltage related to the DC voltage, and the switch is switched on.

[0033] (5) In a circuit device of one embodiment of the present invention, the switching circuit has a second switch, one end of the second switch is connected to the third end of the switch, when the DC voltage is applied in the specific direction, a positive voltage is applied to the other end of the second switch with the potential of the cathode of the diode as a reference, and when the DC voltage is applied in the specific direction, the second switch is switched from off to on when the DC voltage is lower than a predetermined voltage.

[0034] In the above-mentioned one mode, when the second switch is off, the voltage applied to the third terminal of the switch is low, so the switch is off. When a DC voltage is applied in a specific direction, when the DC voltage is lower than a predetermined voltage, the second switch is switched on. At this time, the voltage at the third terminal of the switch rises to a high voltage related to the DC voltage, and the switch is switched on.

[0035] (6) In a circuit device of one embodiment of the present invention, the switching circuit includes a Zener diode and a second resistor having one end connected to the anode of the Zener diode. When the DC voltage is applied in the specific direction, a positive voltage is applied to the cathode of the Zener diode based on the potential of the other end of the second resistor, and the second switch is switched on or off accordingly with the voltage at one end of the second resistor.

[0036] In one of the above methods, when a DC voltage is applied in a specific direction, when the DC voltage is above a predetermined voltage, current flows in the Zener diode and the second resistor in sequence, and the voltage at one end of the second resistor is high. At this time, the switch is disconnected. In the same case, when the DC voltage is lower than the predetermined voltage, the power supply through the Zener diode stops, and the voltage at one end of the second resistor drops. At this time, the second switch is switched to on or off, and the switch is switched to on.

[0037] (7) The circuit device according to one aspect of the present disclosure includes a third switch, and the electrical circuit switches the third switch on or off, and when the DC voltage is applied to the two terminals, supplies power to the electrical device via the third switch.

[0038] In the above-mentioned aspect, the electric circuit controls the power supply to the electric device by switching the third switch on or off.

[0039] [Details of the embodiments of the present disclosure]

[0040] Hereinafter, specific examples of the power supply system according to the embodiment of the present disclosure will be described with reference to the drawings. In addition, the present invention is not limited to these examples, but is indicated by the claims, and is intended to include all changes within the meaning and scope equivalent to the claims.

[0041] (Implementation Method 1)

[0042] Figure 1 1 is a block diagram showing the main structure of the power supply system 1 in the first embodiment. The power supply system 1 is appropriately mounted on a vehicle and includes a battery 10, a power supply control device 11, an electrical device 12, a positive terminal T1, and a negative terminal T2. The battery 10 is detachably connected between the positive terminal T1 and the negative terminal T2. Hereinafter, the voltage of the positive electrode of the battery 10 based on the potential of the negative electrode of the battery 10 is recorded as the battery voltage. The battery voltage is a DC voltage.

[0043] When the positive and negative electrodes of the battery 10 are connected to the positive terminal T1 and the negative terminal T2, respectively, the connection of the battery 10 is a normal connection. When the positive and negative electrodes of the battery 10 are mistakenly connected to the negative terminal T2 and the positive terminal T1, respectively, the connection of the battery 10 is a reverse connection. When the battery 10 is connected to the positive terminal T1 and the negative terminal T2, the battery voltage is applied between the positive terminal T1 and the negative terminal T2. When the connection of the battery 10 is a normal connection, the battery voltage is applied in a specific direction. When the connection of the battery 10 is a reverse connection, the battery voltage is applied in a direction different from the specific direction.

[0044] The power supply control device 11 includes a power supply switch 20, a first switching circuit 21, a second switching circuit 22, a regulator 23, a diode 24, a bypass switch 25, and resistors 26 and 27. The bypass switch 25 is an N-channel FET having a source, a drain, and a gate. The diode 24 is a parasitic diode of the bypass switch 25. Since the parasitic diode of the bypass switch 25 is used as the diode 24, the manufacturing cost of the power supply control device 11 is low.

[0045] In the power supply system 1, the positive terminal T1 is connected to one end of the power switch 20 of the power supply control device 11. The other end of the power switch 20 is connected to one end of the electric device 12. The other end of the electric device 12 is connected to the negative terminal T2.

[0046] In the power supply control device 11, one end of the power supply switch 20 is further connected to the first switching circuit 21, the second switching circuit 22 and the regulator 23. The first switching circuit 21 is further connected to the anode of the diode 24. The cathode of the diode 24 is connected to the negative terminal T2. The source and drain of the bypass switch 25 are respectively connected to the anode and cathode of the diode 24. The resistor 26 is connected between the gate and the source of the bypass switch 25. The gate of the bypass switch 25 is further connected to one end of the resistor 27. The other end of the resistor 27 is connected to the second switching circuit 22. The regulator 23 is further connected to the second switching circuit 22. The second switching circuit 22 is further connected to the negative terminal T2.

[0047] When the connection of the battery 10 is normal, current flows from the positive electrode of the battery 10 to the first switching circuit 21, and the battery 10 applies voltage to the first switching circuit 21. Thus, power is supplied to the first switching circuit 21. The first switching circuit 21 operates when the voltage applied to the first switching circuit 21 is equal to or higher than the operating voltage required for the operation of the first switching circuit 21.

[0048] An on instruction for instructing the power switch 20 to be turned on and an off instruction for instructing the power switch 20 to be turned off are input to the first switching circuit 21. The first switching circuit 21 switches the power switch 20 on when the on instruction is input to the first switching circuit 21. When the connection of the storage battery 10 is normally connected, when the power switch 20 is switched on, the storage battery 10 supplies power to the electrical device 12 via the power switch 20. As a result, the electrical device 12 operates.

[0049] The first switching circuit 21 switches the power supply switch 20 to the off state when a disconnection instruction is input to the first switching circuit 21. When the connection of the storage battery 10 is normally connected, when the power supply switch 20 is switched to the off state, the power supply from the storage battery 10 to the electrical device 12 stops. As a result, the electrical device 12 stops operating.

[0050] In the power supply control device 11 , the first switching circuit 21 switches the power supply switch 20 on or off to control the power supply from the storage battery 10 to the electric device 12 .

[0051] The power supply control device 11 , the power supply switch 20 , and the first switching circuit 21 function as a circuit device, a third switch, and an electric circuit, respectively.

[0052] When the voltage applied to the first switching circuit 21 is lower than the operating voltage or the power supply from the storage battery 10 to the first switching circuit 21 stops, the first switching circuit 21 stops operating. When the first switching circuit 21 stops operating, the power switch 20 is turned off and power is not supplied to the electrical device 12.

[0053] When the battery 10 is normally connected, the regulator 23 reduces the battery voltage to the set voltage when the battery voltage exceeds the preset set voltage. The set voltage is a voltage based on the potential of the negative terminal T2. The battery voltage is, for example, 12V. The set voltage is, for example, 5V.

[0054] The regulator 23 has a diode (not shown). The cathode of the diode is connected to the second switching circuit 22. In the regulator 23, the stepped-down voltage is output to the second switching circuit 22 via the diode. When the battery 10 is normally connected, if the battery voltage is lower than the set voltage, in the regulator 23, the battery voltage is output to the second switching circuit 22 via the diode.

[0055] As described above, the cathode of the diode of the regulator 23 is connected to the second switching circuit 22 , so that the current does not flow in the second switching circuit 22 and the regulator 23 in sequence.

[0056] Regarding the bypass switch 25, when the voltage of the gate based on the potential of the source increases, the resistance value between the drain and the source decreases. Regarding the bypass switch 25, when the voltage of the gate based on the potential of the source is equal to or higher than the first threshold, the resistance value between the drain and the source is small, and the current can flow through the drain and the source. At this time, the bypass switch 25 is turned on.

[0057] In addition, regarding the bypass switch 25, when the voltage of the gate based on the potential of the source is lower than the first threshold, the resistance value between the drain and the source is large, and the current does not flow through the drain and the source. At this time, the bypass switch 25 is turned off. The first threshold is a constant voltage and exceeds zero V.

[0058] In the diode 24, when current flows in the anode and cathode in sequence, a voltage drop occurs. Hereinafter, the magnitude of the voltage drop is described as a forward voltage. The forward voltage is, for example, 0.6V.

[0059] When the connection of the battery 10 is normally connected, when the battery voltage is equal to or higher than the reference voltage, the second switching circuit 22 reduces the gate voltage of the bypass switch 25 based on the potential of the negative terminal T2 to substantially zero V. At this time, in the bypass switch 25, the gate voltage based on the potential of the source is lower than the first threshold value, and the bypass switch 25 is switched from on to off. The reference voltage is constant.

[0060] When the bypass switch 25 is opened while the connection of the storage battery 10 is normally connected, current flows in the positive terminal T1 , the first switching circuit 21 , the diode 24 , and the negative terminal T2 in sequence, and power is supplied to the first switching circuit 21 .

[0061] The path where the current flows sequentially through the positive terminal T1, the first switching circuit 21, the diode 24, and the negative terminal T2 is a supply path for the battery 10 to supply power to the first switching circuit 21. The diode 24 is arranged in the supply path. In the supply path, the source of the bypass switch 25 is arranged on the anode side of the diode 24 in the supply path, and the drain of the bypass switch 25 is arranged on the cathode side of the diode 24. The source, drain, and gate of the bypass switch 25 correspond to the first end, the second end, and the third end.

[0062] When current flows sequentially through the positive terminal T1, the first switching circuit 21, the diode 24, and the negative terminal T2, a voltage drop occurs in the diode 24. In this case, the applied voltage applied to the first switching circuit 21 is lower than the battery voltage. Specifically, the applied voltage is substantially consistent with the voltage calculated by subtracting the forward voltage of the diode 24 from the battery voltage.

[0063] When the connection of the battery 10 is normally connected, if the battery voltage is lower than the reference voltage, the second switching circuit 22 increases the gate voltage of the bypass switch 25 based on the potential of the negative terminal T2 to a voltage close to the output voltage of the regulator 23. As a result, in the bypass switch 25, the gate voltage based on the potential of the source increases to a voltage higher than the first threshold, and the bypass switch 25 is switched from off to on.

[0064] When the bypass switch 25 is turned on, the resistance value of the bypass switch 25 is sufficiently small. Therefore, when the connection of the storage battery 10 is normally connected, when the bypass switch 25 is turned on, the current flows through the positive terminal T1, the first switching circuit 21, the bypass switch 25, and the negative terminal T2 in sequence, and the power is supplied to the first switching circuit 21. At this time, no voltage drop occurs in the diode 24, so the applied voltage applied to the first switching circuit 21 is substantially consistent with the battery voltage.

[0065] When the battery 10 is connected in reverse, the second switching circuit 22 does not output a voltage to the gate of the bypass switch 25. In this case, the current does not flow through the resistors 26 and 27, so the gate voltage of the bypass switch 25 based on the potential of the source is zero V, which is lower than the positive first threshold. Therefore, when the battery 10 is connected in reverse, the bypass switch 25 is opened.

[0066] When the battery 10 is connected reversely, current does not flow through the diode 24 and the bypass switch 25. Therefore, when the battery 10 is connected reversely, current does not flow through the first switching circuit 21, and a voltage with a wrong polarity can be prevented from being applied to the first switching circuit 21.

[0067] When the connection of the storage battery 10 is reversed, current does not flow in the first switching circuit 21, so power is not supplied to the first switching circuit 21. As described above, when power is not supplied to the first switching circuit 21, the power supply switch 20 is turned off. Therefore, when the connection of the storage battery 10 is reversed, current does not flow in the electrical device 12, and power is not supplied to the electrical device 12. When power is not supplied to the electrical device 12, the electrical device 12 stops operating.

[0068] Figure 2 2 is a circuit diagram of the second switching circuit 22. The second switching circuit 22 includes five resistors 30 to 34, a switch 35, and a Zener diode 36. The switch 35 is an NPN bipolar transistor.

[0069] One end of the resistor 30 and the collector of the switch 35 are connected to the other end of the resistor 27. As described above, one end of the resistor 27 is connected to the gate of the bypass switch 25. Therefore, one end of the resistor 30 and the collector of the switch 35 are connected to the gate of the bypass switch 25 via the resistor 27. The switch 35 functions as a second switch.

[0070] The other end of the resistor 30 is connected to the regulator 23. The emitter of the switch 35 is connected to the negative terminal T2. The resistor 31 is connected between the base and the emitter of the switch 35. The base of the switch 35 is further connected to one end of the resistor 32. The other end of the resistor 32 is connected to one end of each of the resistors 33 and 34. The other end of the resistor 33 is connected to the negative terminal T2. The other end of the resistor 34 is connected to the anode of the Zener diode 36. Therefore, the anode of the Zener diode 36 is connected to one end of the resistor 33 via the resistor 34. The cathode of the Zener diode 36 is connected to the positive terminal T1.

[0071] When the battery 10 is normally connected, the regulator 23 steps down the battery voltage to a set voltage and applies the stepped-down voltage to the other end of the resistor 30. The stepped-down voltage is a positive voltage based on the potential of the negative terminal T2, that is, the potential of the emitter of the switch 35.

[0072] Regarding the switching switch 35, when the voltage of the base electrode based on the potential of the emitter electrode rises, the resistance value between the collector and the emitter electrode decreases. Regarding the switching switch 35, when the voltage of the base electrode based on the potential of the emitter electrode is greater than the second threshold value, the resistance value between the collector and the emitter electrode is small, and the current can flow through the collector and the emitter electrode. At this time, the switching switch 35 is turned on.

[0073] In addition, regarding the switching switch 35, when the voltage of the base based on the potential of the emitter is lower than the second threshold, the resistance value between the collector and the emitter is large, and the current does not flow through the collector and the emitter. At this time, the switching switch 35 is turned off. The second threshold is a constant voltage and exceeds zero V.

[0074] The switching switch 35 is switched on or off in accordance with the voltage at one end of the resistor 33 based on the potential of the negative terminal T2. When the voltage at one end of the resistor 33 exceeds zero V, current flows through the resistors 32 and 31 in sequence, and a voltage drop is generated at the resistor 31. At this time, in the switching switch 35, a positive voltage is applied to the base based on the potential of the emitter. The greater the amplitude of the voltage drop generated at the resistor 31, the higher the positive voltage. The greater the current flowing in the resistor 31, the greater the amplitude of the voltage drop generated at the resistor 31.

[0075] The higher the voltage at one end of the resistor 33 based on the potential of the negative terminal T2, the larger the current flowing through the resistor 31, and the higher the voltage at the base based on the potential of the emitter. As described above, the switch 35 is switched on or off according to the voltage at the base based on the potential of the emitter.

[0076] In the Zener diode 36, when the voltage of the cathode based on the potential of the anode is equal to or higher than a constant breakdown voltage, current flows sequentially through the cathode and anode. In the Zener diode 36, when the current flows sequentially through the cathode and anode, the voltage between both ends of the Zener diode 36 is maintained at the breakdown voltage. In the Zener diode 36, when the voltage of the cathode based on the potential of the anode is lower than the breakdown voltage, the current passing through the cathode and anode is stopped.

[0077] Figure 3 2 is a timing chart for explaining the operation of the second switching circuit 22. Figure 3 In FIG. 1 , the change of the battery voltage and the change of the switching switch 35 and the bypass switch 25 in relation to the on and off state of each are shown. The horizontal axis shows the time for these changes. Figure 3 , the transition of the battery voltage when the connection of the battery 10 is normal is shown. Vr represents a reference voltage.

[0078] The battery voltage changes for various reasons. In the battery 10, current is output through an internal resistor (not shown). When current flows through the internal resistor, a voltage drop occurs at the internal resistor. The larger the current flowing through the internal resistor, the larger the voltage drop. The larger the voltage drop, the lower the battery voltage. Therefore, when the current output through the internal resistor changes, the voltage drop changes, and the battery voltage changes.

[0079] For example, when the object to which the battery 10 supplies power includes a starter different from the electrical device 12, when the starter is operating, a large current flows through the internal resistance of the battery 10, and the battery voltage drops significantly. The starter is a motor for starting the engine. When the starter stops operating, the current flowing through the internal resistance of the battery 10 drops, and the battery voltage rises significantly.

[0080] Furthermore, the battery voltage also changes according to the electric power stored in battery 10 .

[0081] like Figure 2 As shown, when the connection of the battery 10 is normally connected, the battery voltage as a positive voltage is applied to the cathode of the Zener diode 36 with the potential of the negative terminal T2, that is, the other end of the resistor 33 as a reference. When the connection of the battery 10 is normally connected, when the battery voltage is higher than the reference voltage Vr, the voltage of the cathode with the potential of the anode as a reference is higher than the breakdown voltage in the Zener diode 36. At this time, the current flows in the Zener diode 36 and the resistors 34 and 33 in sequence, and flows in the Zener diode 36 and the resistors 34, 32, and 31 in sequence.

[0082] When the current flows sequentially through the cathode and anode of the Zener diode 36, the voltage at one end of the resistor 31 based on the potential of the negative terminal T2 is sufficiently high, and the voltage at the base based on the potential of the emitter in the switch 35 is equal to or higher than the second threshold. In this case, the switch 35 is turned on.

[0083] When the switch 35 is turned on, the gate voltage of the bypass switch 25 based on the potential of the negative terminal T2 is substantially zero V. At this time, the gate voltage of the bypass switch 25 based on the potential of the source is lower than the positive first threshold, and the bypass switch 25 is turned off.

[0084] As described above, when the connection of the storage battery 10 is normal, when the storage battery voltage is higher than the reference voltage Vr, Figure 3 As shown, the switch 35 and the bypass switch 25 are turned on and off respectively. Since the bypass switch 25 is turned off, the current flows in the first switching circuit 21 and the diode 24 in sequence, and the applied voltage applied to the first switching circuit 21 is substantially consistent with the voltage calculated by subtracting the forward voltage of the diode 24 from the battery voltage.

[0085] When the battery voltage is lower than the reference voltage Vr, the voltage of the cathode based on the potential of the anode in the Zener diode 36 is lower than the breakdown voltage, and the energization through the Zener diode 36 stops. At this time, the current does not flow in the resistor 33, so the voltage at one end of the resistor 33 based on the potential of the negative terminal T2 drops to zero V. At this time, the current does not flow in the resistor 31, so the voltage of the base based on the potential of the emitter in the switch 35 is zero V, which is lower than the positive second threshold. As a result, the switch 35 is switched from on to off.

[0086] When the switch 35 is switched from on to off, the voltage of the gate of the bypass switch 25 based on the potential of the negative terminal T2 rises to a voltage close to the output voltage of the regulator 23, and the bypass switch 25 is switched from off to on.

[0087] As described above, when the connection of the storage battery 10 is normal, when the storage battery voltage is lower than the reference voltage Vr, as shown in FIG. Figure 3 As shown, the switch 35 is switched from on to off, and the bypass switch 25 is switched from off to on. When the bypass switch 25 is on, current flows sequentially in the first switching circuit 21 and the bypass switch 25, and the voltage applied to the first switching circuit 21 is substantially the same as the battery voltage.

[0088] When the battery voltage is higher than the reference voltage Vr, the voltage of the cathode based on the potential of the anode in the Zener diode 36 is higher than the breakdown voltage, and the current flows in the cathode and anode of the Zener diode 36 in sequence again. As a result, the voltage at one end of the resistor 33 based on the potential of the negative terminal T2 rises to a sufficiently high voltage, and the voltage of the base based on the potential of the emitter in the switch 35 is higher than the second threshold. As a result, the switch 35 is switched from off to on. When the switch 35 is switched from off to on, the bypass switch 25 is switched from on to off as described above.

[0089] As described above, when the connection of the storage battery 10 is normal, when the storage battery voltage is higher than the reference voltage Vr, Figure 3 As shown, the switch 35 is switched from off to on, and the bypass switch 25 is switched from on to off. As a result, the current flows through the first switching circuit 21 and the diode 24 in sequence again, and the voltage applied to the first switching circuit 21 returns to the voltage calculated by subtracting the forward voltage of the diode 24 from the battery voltage.

[0090] When the battery 10 is connected in reverse, the current flows in the negative terminal T2, the resistors 33 and 34, the Zener diode 36, and the positive terminal T1 in sequence, and flows in the negative terminal T2, the resistors 31, 32, 34, the Zener diode 36, and the positive terminal T1 in sequence. At this time, in the switch 35, the voltage of the base based on the potential of the emitter is a negative voltage, which is lower than the positive second threshold value. The switch 35 is turned off.

[0091] When the connection of the storage battery 10 is reversed, the regulator 23 does not operate, and the current does not flow through the resistor 26. Therefore, the voltage is not output from the second switching circuit 22 to the gate of the bypass switch 25. At this time, as described above, the bypass switch 25 is turned off. When the connection of the storage battery 10 is reversed, as described above, there is no problem that the current flows through the second switching circuit 22.

[0092] Figure 4 1 is an explanatory diagram of the effect of the power supply control device 11. Figure 4 In FIG. 1 , the thin solid line indicates the change of the battery voltage, and the thick solid line indicates the change of the applied voltage applied to the first switching circuit 21. The thick line indicates the change of the portion where the battery voltage and the applied voltage are the same. The horizontal axis shows the change of the battery voltage and the applied voltage. Figure 4 , transitions of the battery voltage and the applied voltage are shown when the connection of the battery 10 is normal.

[0093] like Figure 4 As shown in FIG. 1 , when the battery voltage is higher than the reference voltage, the bypass switch 25 is turned off, so that the current flows sequentially through the first switching circuit 21 and the diode 24. The voltage applied to the first switching circuit 21 is substantially consistent with the voltage calculated by subtracting the forward voltage of the diode 24 from the battery voltage. When the battery voltage is lower than the reference voltage, the bypass switch 25 is turned on, so that the current flows sequentially through the first switching circuit 21 and the bypass switch 25. The voltage applied to the first switching circuit 21 is substantially consistent with the battery voltage.

[0094] Therefore, when the battery 10 is normally connected, if the battery voltage is lower than the reference voltage, the bypass switch 25 is switched from off to on, and the applied voltage rises to the battery voltage. Therefore, the possibility that the applied voltage is lower than the operating voltage required for the operation of the first switching circuit 21 and the operation of the first switching circuit 21 stops is low.

[0095] In addition, if Figure 4As shown, the reference voltage Vr is preferably equal to or higher than the voltage calculated by adding the forward voltage of the diode 24 to the minimum value of the battery voltage. In this case, the minimum value of the applied voltage is equal to or higher than the minimum value of the battery voltage and does not fall below the minimum value of the battery voltage.

[0096] As a structure with a low possibility of stopping the operation of the first switching circuit 21, a structure in which the diode 24 is arranged on the positive terminal T1 side of the first switching circuit 21 instead of on the negative terminal T2 side of the first switching circuit 21 can be considered. In this structure, in order to realize the second switching circuit 22 without using a boost circuit for boosting the battery voltage, it is necessary to use, for example, an expensive P-channel FET as the bypass switch 25.

[0097] In the power supply control device 11, since the diode 24 is disposed on the cathode terminal T2 side of the first switching circuit 21, an inexpensive N-channel FET can be used as the bypass switch 25. Therefore, the manufacturing cost of the power supply control device 11 is inexpensive.

[0098] The transistor used as the switch 35 is not limited to an NPN bipolar transistor, and may be an N-channel FET, for example. In this case, the drain, source, and gate of the FET correspond to the collector, emitter, and base of the bipolar transistor, respectively.

[0099] (Implementation Method 2)

[0100] Figure 5 1 is a circuit diagram of the second switching circuit 22 in the second embodiment.

[0101] Next, Embodiment 2 will be described with respect to points different from Embodiment 1. The other structures except for the structures described below are the same as those of Embodiment 1. Therefore, the same reference numerals as those of Embodiment 1 are attached to the components common to Embodiment 1, and the description thereof is omitted.

[0102] When the second embodiment is compared with the first embodiment, the structure of the second switching circuit 22 of the power supply control device 11 is different. In the second embodiment, the second switching circuit 22 has resistors 30, 32-34 and a Zener diode 36 as in the first embodiment. The second switching circuit 22 has a resistor 40 and a switch 41 instead of the resistor 31 and the switch 35. The switch 41 is a P-channel FET.

[0103] The resistors 33 and 34 and the Zener diode 36 are connected in the same manner as in the first embodiment. One end of the resistor 30 is connected to the regulator 23. The other end of the resistor 30 is connected to the source of the switch 41. The drain of the switch 41 is connected to the other end of the resistor 27. As described in the description of the first embodiment, one end of the resistor 27 is connected to the gate of the bypass switch 25. Therefore, the drain of the switch 41 is connected to the gate of the bypass switch 25 via the resistor 27. In the second embodiment, the switch 41 functions as a second switch.

[0104] The resistor 40 is connected between the gate and source of the switch 41. The gate of the switch 41 is further connected to one end of the resistor 32. The other end of the resistor 32 is connected to one end of each of the resistors 33 and 34.

[0105] When the battery 10 is normally connected, the regulator 23 steps down the battery voltage to a set voltage and applies the stepped-down voltage to one end of the resistor 30. The stepped-down voltage is a positive voltage based on the potential of the negative terminal T2, that is, the potential of the cathode of the diode 24.

[0106] Regarding the switching switch 41, when the voltage of the gate based on the potential of the source decreases, the resistance value between the source and the drain decreases. Regarding the switching switch 41, when the voltage of the gate based on the potential of the source is below the third threshold, the resistance value between the source and the drain is small, and the current can flow through the source and the drain. At this time, the switching switch 41 is turned on.

[0107] In addition, regarding the switching switch 41, when the voltage of the gate based on the potential of the source exceeds the third threshold, the resistance value between the source and the drain is large, and the current does not flow through the source and the drain. At this time, the switching switch 41 is turned off. The third threshold is a constant voltage and is lower than zero V.

[0108] The switch 41 is switched on or off in accordance with the voltage at one end of the resistor 33 based on the potential of the negative terminal T2. When the voltage at one end of the resistor 33 based on the potential of the negative terminal T2 is equal to or higher than the voltage output from the regulator 23, that is, the set voltage, current does not flow through the resistors 30, 32, and 40. At this time, in the switch 41, the voltage of the gate based on the potential of the source is zero V, exceeding the negative third threshold. Therefore, the switch 41 is turned off.

[0109] When the voltage at one end of the resistor 33 based on the potential of the negative terminal T2 is lower than the set voltage, the current flows from the regulator 23 to the resistors 30, 40, 32, and 33 in sequence, and a voltage drop occurs at the resistor 40. As a result, the voltage of the gate based on the potential of the source decreases in the switching switch 41. The greater the current flowing through the resistor 40, the greater the magnitude of the voltage drop generated at the resistor 40. In addition, the greater the magnitude of the voltage drop generated at the resistor 40, the lower the voltage of the gate based on the potential of the source.

[0110] Assuming that the voltage at one end of the resistor 33 based on the potential of the negative terminal T2 is lower than the set voltage, the difference between the voltage at one end of the resistor 33 and the set voltage is small. In this case, the current flowing through the resistor 40 is small, so in the switching switch 41, the voltage of the gate based on the potential of the source exceeds the third threshold value, and the switching switch 41 is turned off.

[0111] Assuming that the voltage at one end of the resistor 33 based on the potential of the negative terminal T2 is lower than the set voltage, the difference between the voltage at one end of the resistor 33 and the set voltage is large. In this case, the current flowing through the resistor 40 is large, so in the switching switch 41, the voltage of the gate based on the potential of the source is lower than the third threshold value, and the switching switch 41 is turned on.

[0112] As described above, when the connection of the storage battery 10 is normally connected, when the voltage at one end of the resistor 33 based on the potential of the negative terminal T2 is high, the switch 41 is turned off. In the same case, when the voltage at one end of the resistor 33 based on the potential of the negative terminal T2 is low, the switch 41 is turned on.

[0113] As in the first embodiment, when the connection of the battery 10 is normal, the battery voltage as a positive voltage is applied to the cathode of the Zener diode 36 with the potential of the negative terminal T2 as a reference. When the connection of the battery 10 is normal, when the battery voltage is higher than the reference voltage Vr, the voltage of the cathode with the potential of the anode as a reference in the Zener diode 36 is higher than the breakdown voltage. At this time, the current flows in the Zener diode 36 and the resistors 34 and 33 in sequence, and the voltage at one end of the resistor 33 with the potential of the negative terminal T2 as a reference is higher. As a result, the switch 41 is turned off.

[0114] When the switch 41 is turned off, no voltage is output from the second switching circuit 22 to the gate of the bypass switch 25. In this case, current does not flow through the resistor 26, so the gate voltage of the bypass switch 25, which is based on the potential of the source, is zero V, which is lower than the positive first threshold. Therefore, the bypass switch 25 is turned off.

[0115] When the connection of the battery 10 is normally connected, when the battery voltage is lower than the reference voltage Vr, the voltage of the cathode based on the potential of the anode in the Zener diode 36 is lower than the breakdown voltage, and the energization through the Zener diode 36 is stopped. At this time, the voltage at one end of the resistor 33 based on the potential of the negative terminal T2 drops to a low voltage, and the switch 41 is switched on.

[0116] When the changeover switch 41 is switched on, the voltage of the gate of the bypass switch 25 based on the potential of the negative terminal T2 rises to a voltage close to the output voltage of the regulator 23 , and the bypass switch 25 is switched on.

[0117] When the battery 10 is normally connected, if the battery voltage is equal to or higher than the reference voltage Vr, the current flows again through the Zener diode 36 and the switch 41 is switched off. As a result, the bypass switch 25 is also switched off.

[0118] As described above, when the connection of the battery 10 is normally connected, when the battery voltage is lower than the reference voltage Vr, the switch 41 and the bypass switch 25 are each switched from off to on. In the same case, when the battery voltage is higher than the reference voltage Vr, the switch 41 and the bypass switch 25 are each switched from on to off.

[0119] When the connection of the battery 10 is reversed, the current flows in the negative terminal T2, the resistors 33 and 34, the Zener diode 36, and the positive terminal T1 in sequence. The cathode of the regulator 23 is connected to one end of the resistor 30, so the current does not flow in the resistors 30, 32, and 40. At this time, in the switching switch 41, the voltage of the gate based on the potential of the source is zero V, which exceeds the negative third threshold value. Therefore, the switching switch 41 is turned off. When the switching switch 41 is turned off, the bypass switch 25 is turned off as described above.

[0120] When the connection of the storage battery 10 is reversed, there is no problem in that the current flows via the second switching circuit 22 as described above.

[0121] In the second embodiment, similarly to the first embodiment, when the battery 10 is normally connected, the bypass switch 25 is switched from off to on when the battery voltage is lower than the reference voltage. Similarly, when the battery voltage is higher than the reference voltage, the bypass switch 25 is switched from on to off. When the battery 10 is reversely connected, the bypass switch 25 is turned off. Therefore, the power supply control device 11 in the second embodiment also has the same effect as the power supply control device 11 in the first embodiment.

[0122] The transistor used as the switch 41 is not limited to a P-channel FET, and may be, for example, a PNP bipolar transistor. In this case, the emitter, collector, and base of the bipolar transistor correspond to the source, drain, and gate of the FET, respectively.

[0123] (Implementation 3)

[0124] Figure 6 This is a block diagram showing a main part configuration of a power supply system 1 in the third embodiment.

[0125] Next, the differences from Embodiment 1 will be described with respect to Embodiment 3. The other configurations except for the configuration described below are the same as those of Embodiment 1. Therefore, the same reference numerals as those of Embodiment 1 are given to the configurations common to Embodiment 1, and the description thereof is omitted.

[0126] The difference between Embodiments 1 and 3 is whether the power supply control device 11 has a regulator 23. The power supply control device 11 in Embodiment 3 has other components other than the regulator 23 among the components of the power supply control device 11 in Embodiment 1. The other end of the resistor 30 of the second switching circuit 22 is connected to one end of the power supply switch 20.

[0127] When the connection of the storage battery 10 is normal, when the storage battery voltage is equal to or higher than the reference voltage, similarly to the first embodiment, the switch 35 is turned on and the bypass switch 25 is turned off.

[0128] In the same case, when the battery voltage is lower than the reference voltage, the switch 35 is switched from on to off in the same manner as in Embodiment 1. When the switch 35 is switched off, the voltage of the gate of the bypass switch 25 based on the potential of the negative terminal T2 rises to a voltage close to the battery voltage, and the bypass switch 25 is switched on.

[0129] When the connection of the storage battery 10 is normal, when the storage battery voltage is equal to or higher than the reference voltage, similarly to the first embodiment, the switch 35 is switched from off to on, and the bypass switch 25 is switched from on to off.

[0130] When the connection of the storage battery 10 is reversed, the changeover switch 35 and the bypass switch 25 are opened similarly to the first embodiment.

[0131] In the third embodiment, the switch 35 and the bypass switch 25 are switched on and off as in the first embodiment. Therefore, the power supply control device 11 in the third embodiment has the same effects as the power supply control device 11 in the first embodiment.

[0132] (Implementation 4)

[0133] The configuration of the second switching circuit 22 in the third embodiment is not limited to the configuration of the second switching circuit 22 in the first embodiment.

[0134] Next, the differences from Embodiment 3 will be described with respect to Embodiment 4. The other structures except the structures described below are the same as those of Embodiment 3. Therefore, the same reference numerals as those of Embodiment 3 are attached to the structural parts common to Embodiment 3, and the description thereof is omitted.

[0135] The structure of the second switching circuit 22 in the fourth embodiment is similar to that of the second switching circuit 22 in the second embodiment (see Figure 5 In the power supply control device 11 in the fourth embodiment, one end of the resistor 30 of the second switching circuit 22 is connected to one end of the power supply switch 20 .

[0136] When the connection of the storage battery 10 is normally connected, when the voltage at one end of the resistor 33 based on the potential of the negative terminal T2 is high, the switch 41 is turned off as in Embodiment 2. In the same case, when the voltage at one end of the resistor 33 based on the potential of the negative terminal T2 is low, the switch 41 is turned on as in Embodiment 2.

[0137] When the battery 10 is normally connected, if the battery voltage is equal to or higher than the reference voltage, the voltage at one end of the resistor 33 based on the potential of the negative terminal T2 is high, and the switch 41 is turned off. When the switch 41 is turned off, the bypass switch 25 is turned off as in the second embodiment.

[0138] When the connection of the battery 10 is normally connected, if the battery voltage is lower than the reference voltage, the voltage at one end of the resistor 33 based on the potential of the negative terminal T2 becomes low, and the switch 41 is switched from off to on as in Embodiment 2. When the switch 41 is switched on, the voltage at the gate of the bypass switch 25 based on the potential of the negative terminal T2 rises to a voltage close to the battery voltage, and the bypass switch 25 is switched on.

[0139] When the connection of the battery 10 is normally connected, when the battery voltage is higher than the reference voltage, the voltage at one end of the resistor 33 based on the potential of the negative terminal T2 becomes high, and similarly to the second embodiment, the switching switch 41 is switched from on to off, and the bypass switch 25 is also switched from on to off.

[0140] When the connection of the storage battery 10 is reversed, the current flows in the negative terminal T2, the resistors 33, 34, the Zener diode 36, and the positive terminal T1 in sequence, and flows in the negative terminal T2, the resistors 33, 32, 40, 30, and the positive terminal T1 in sequence. At this time, in the switching switch 41, the voltage of the gate based on the potential of the source is a positive voltage, which is equal to or greater than the negative third threshold value. Therefore, the switching switch 41 is turned off. When the switching switch 41 is turned off, the bypass switch 25 is also turned off as in the second embodiment.

[0141] In the fourth embodiment, the switch 41 and the bypass switch 25 are switched on and off as in the second embodiment. Therefore, the power supply control device 11 in the fourth embodiment has the same effects as the power supply control device 11 in the second embodiment.

[0142] (Implementation method 5)

[0143] Figure 7 This is a block diagram showing a main part configuration of a power supply system 1 in the fifth embodiment.

[0144] Next, the differences from Embodiment 1 will be described with respect to Embodiment 5. The other structures except the structures described below are the same as those of Embodiment 1. Therefore, the same reference numerals as those of Embodiment 1 are attached to the structural parts common to Embodiment 1, and the description thereof is omitted.

[0145] When Embodiment 5 is compared with Embodiment 1, the transistor used as the bypass switch is different. The power supply control device 11 in Embodiment 5 has other components other than the bypass switch 25 and the resistor 26 among the components of the power supply control device 11 in Embodiment 1. The power supply control device 11 in Embodiment 5 has a bypass switch 50 and a resistor 51 instead of the bypass switch 25 and the resistor 26.

[0146] The bypass switch 50 is an NPN type bipolar transistor. When a bipolar transistor is manufactured, no parasitic diode is generated. Therefore, the diode 24 in the third embodiment is a normal element.

[0147] The anode and cathode of the diode 24 are connected to the collector and emitter of the bypass switch 50, respectively. The resistor 51 is connected between the base and emitter of the bypass switch 50. The base of the bypass switch 50 is further connected to one end of the resistor 27.

[0148] Regarding the bypass switch 50, when the voltage of the base electrode based on the potential of the emitter electrode rises, the resistance value between the collector and the emitter electrode decreases. Regarding the bypass switch 50, when the voltage of the base electrode based on the potential of the emitter electrode is equal to or higher than the fourth threshold, the resistance value between the collector and the emitter electrode is small, and the current can flow through the collector and the emitter electrode. At this time, the bypass switch 50 is turned on.

[0149] In addition, regarding the bypass switch 50, when the voltage of the base based on the potential of the emitter is lower than the fourth threshold, the resistance value between the collector and the emitter is large, and the current does not flow through the collector and the emitter. At this time, the bypass switch 50 is turned off. The fourth threshold is a constant voltage exceeding zero V.

[0150] When the battery 10 is normally connected and the battery voltage is equal to or higher than the reference voltage, the switch 35 (see Figure 2 ) is turned on. At this time, current does not flow in the resistor 51, and in the bypass switch 50, the voltage of the base based on the potential of the emitter is zero V, which is lower than the fourth positive threshold. As a result, the bypass switch 50 is turned off.

[0151] When the connection of the battery 10 is normally connected, if the battery voltage is lower than the reference voltage, the switch 35 is switched from on to off as in Embodiment 1. When the switch 35 is switched to off, the voltage of the base of the bypass switch 50 based on the potential of the emitter of the bypass switch 50 rises to a voltage close to the output voltage of the regulator 23 and becomes equal to or higher than the fourth threshold value. As a result, the bypass switch 50 is switched from off to on.

[0152] When the connection of the storage battery 10 is normal, when the storage battery voltage is equal to or higher than the reference voltage, similarly to the first embodiment, the switch 35 is switched from off to on, and the bypass switch 50 is switched from on to off.

[0153] When the battery 10 is connected in reverse, the switch 35 is opened as in Embodiment 1. In addition, since the diode of the regulator 23 is connected to the other end of the resistor 30, when the battery 10 is connected in reverse, the current does not flow through the resistor 51 and the bypass switch 50 is also opened.

[0154] In Embodiment 5, the switching of the switch 35 and the bypass switch 50 is performed in the same manner as the switching of the switch 35 and the bypass switch 25 in Embodiment 1. Therefore, the power supply control device 11 in Embodiment 5 has the same effect as the power supply control device 11 in Embodiment 1.

[0155] In addition, in the power supply control device 11 in the fifth embodiment, the regulator 23 can also be removed in the same manner as in the third embodiment. In this case, the switching of the switching switch 35 and the bypass switch 25 in the third embodiment is performed in the same manner as the switching of the switching switch 35 and the bypass switch 50 in the third embodiment. When the connection of the battery 10 is reversed, the current flows in the negative terminal T2, the resistors 51, 27, 30 and the positive terminal T1 in sequence. At this time, in the bypass switch 50, the voltage of the base based on the potential of the emitter is a negative voltage, which is lower than the fourth positive threshold. As a result, the bypass switch 50 is disconnected.

[0156] (Implementation 6)

[0157] The configuration of the second switching circuit 22 in the fifth embodiment is not limited to the configuration of the second switching circuit 22 in the first embodiment.

[0158] Next, the differences from Embodiment 5 will be described with respect to Embodiment 6. The other structures except the structures described below are the same as those of Embodiment 5. Therefore, the same reference numerals as those of Embodiment 5 are attached to the structural parts common to Embodiment 5, and the description thereof is omitted.

[0159] The structure of the second switching circuit 22 in the sixth embodiment is similar to that of the second switching circuit 22 in the second embodiment (see Figure 5 ) have the same structure.

[0160] When the battery 10 is normally connected and the battery voltage is equal to or higher than the reference voltage, the switch 41 of the second switching circuit 22 is turned off as in Embodiment 2. At this time, no current flows through the resistor 51 and the bypass switch 50 is turned off.

[0161] When the connection of the storage battery 10 is normally connected, if the storage battery voltage is lower than the reference voltage, the switch 41 is switched from off to on as in Embodiment 2. When the switch 41 is switched on, the voltage of the base of the bypass switch 50 based on the potential of the emitter of the bypass switch 50 rises to a voltage close to the output voltage of the regulator 23 and becomes equal to or higher than the fourth threshold value. As a result, the bypass switch 50 is switched from off to on.

[0162] When the connection of the storage battery 10 is normal, when the storage battery voltage is equal to or higher than the reference voltage, similarly to the second embodiment, the switch 41 is switched from on to off and the bypass switch 50 is switched from on to off.

[0163] When the battery 10 is connected in reverse, the switch 41 is opened as in Embodiment 2. In addition, since the diode of the regulator 23 is connected to one end of the resistor 30, when the battery 10 is connected in reverse, current does not flow through the resistor 51 and the bypass switch 50 is also opened.

[0164] In Embodiment 6, the switching of the switch 41 and the bypass switch 50 is performed in the same manner as the switching of the switch 41 and the bypass switch 25 in Embodiment 2. Therefore, the power supply control device 11 in Embodiment 6 has the same effect as the power supply control device 11 in Embodiment 2.

[0165] In addition, in the power supply control device 11 in the sixth embodiment, the regulator 23 can also be removed in the same manner as in the fourth embodiment. In this case, the switching of the switching switch 41 and the bypass switch 25 in the fourth embodiment is performed in the same manner as the switching of the switching switch 41 and the bypass switch 50 in the same manner as the switching of the switching switch 41 and the bypass switch 25 in the fourth embodiment. When the connection of the battery 10 is reversed, the current flows in the negative terminal T2, the resistors 51, 27, 30 and the positive terminal T1 in sequence. At this time, in the bypass switch 50, the voltage of the base based on the potential of the emitter is a negative voltage, which is lower than the fourth positive threshold. As a result, the bypass switch 50 is disconnected.

[0166] In Embodiments 1-6, the electric circuit disposed upstream of diode 24 in the power supply path of battery 10 is not limited to first switching circuit 21. The electric circuit disposed upstream of diode 24 may be any circuit that operates when supplied with power from battery 10.

[0167] The disclosed embodiments 1 to 6 are illustrative in all aspects and are not restrictive. The scope of the present invention is indicated by the claims rather than the above meaning, and is intended to include all changes within the meaning and scope equivalent to the claims.

[0168] Description of Reference Numerals

[0169] 1 Power System

[0170] 10. Battery

[0171] 11 Power supply control device (circuit device)

[0172] 12 Electrical equipment

[0173] 20 Power switch (third switch)

[0174] 21 First switching circuit (electrical circuit)

[0175] 22. Second switching circuit

[0176] 23 Regulator

[0177] 24 Diode

[0178] 25, 50 Bypass switch

[0179] 26, 27, 30-34, 40, 51 resistors

[0180] 35, 41 Switch (Second Switch)

[0181] 36 Zener diode

[0182] T1 positive terminal

[0183] T2 negative terminal

[0184] Vr reference voltage

Claims

1. A circuit device comprising an electric circuit to which power is supplied when a DC voltage is applied between two terminals, The circuit device comprises: a diode disposed in a supply path for supplying electric power to the electric circuit; a switch connected between two ends of the diode; and a switching circuit that switches the switch from off to on when the DC voltage is applied in a specific direction and when the DC voltage is lower than a predetermined voltage, When the DC voltage is applied in the specific direction, when the switch is turned off, current flows in the electrical circuit and the diode in sequence. The switch is a transistor, The switch has: a first end disposed on the anode side of the diode in the supply path; A second end is arranged on the cathode side of the diode in the supply path; and The third end, When the voltage at the third end increases, the resistance value between the first end and the second end decreases. The switching circuit switches the switch from off to on by increasing the voltage of the third terminal, The switching circuit has: a resistor, one end of which is connected to the third end of the switch; and a second switch, one end of which is connected to the third end of the switch, When the DC voltage is applied in the specific direction, a positive voltage is applied to the other end of the resistor based on the potential of the other end of the second switch. When the DC voltage is applied in the specific direction, the second switch is switched from on to off when the DC voltage is lower than a predetermined voltage. The switching circuit comprises: Zener diodes; and a second resistor, one end of which is connected to the anode of the Zener diode, When the DC voltage is applied in the specific direction, a positive voltage is applied to the cathode of the Zener diode based on the potential of the other end of the second resistor. The second switch is switched on or off according to a voltage at one end of the second resistor.

2. A circuit device comprising an electrical circuit to which power is supplied when a DC voltage is applied between two terminals, The circuit device comprises: a diode disposed in a supply path for supplying electric power to the electric circuit; a switch connected between two ends of the diode; and a switching circuit that switches the switch from off to on when the DC voltage is applied in a specific direction and when the DC voltage is lower than a predetermined voltage, When the DC voltage is applied in the specific direction, when the switch is turned off, current flows in the electrical circuit and the diode in sequence. The switch is a transistor, The switch has: a first end disposed on the anode side of the diode in the supply path; A second end is arranged on the cathode side of the diode in the supply path; and The third end, When the voltage at the third end increases, the resistance value between the first end and the second end decreases. The switching circuit switches the switch from off to on by increasing the voltage of the third terminal, The switching circuit has a second switch, one end of the second switch is connected to the third end of the switch, When the DC voltage is applied in the specific direction, a positive voltage is applied to the other end of the second switch based on the potential of the cathode of the diode. When the DC voltage is applied in the specific direction, the second switch is switched from off to on when the DC voltage is lower than a predetermined voltage. The switching circuit comprises: Zener diodes; and a second resistor, one end of which is connected to the anode of the Zener diode, When the DC voltage is applied in the specific direction, a positive voltage is applied to the cathode of the Zener diode based on the potential of the other end of the second resistor. The second switch is switched on or off according to a voltage at one end of the second resistor.

3. The circuit arrangement according to claim 1 or 2, wherein: The switch is an N-channel FET. The diode is a parasitic diode of the switch.

4. The circuit arrangement according to claim 1 or 2, wherein: The circuit device comprises a third switch, The electrical circuit switches the third switch on or off. When the DC voltage is applied to the two terminals, power is supplied to the electrical device via the third switch.

5. The circuit arrangement according to claim 3, wherein: The circuit device comprises a third switch, The electrical circuit switches the third switch on or off. When the DC voltage is applied to the two terminals, power is supplied to the electrical device via the third switch.

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