Power conversion device and power conversion system

Abstract

To obtain a power conversion device capable of protecting a circuit.SOLUTION: A power conversion device according to an embodiment of the present disclosure includes a power input terminal, a power output terminal, a power conversion circuit, a sensor circuit capable of generating a detection voltage corresponding to a voltage at the power output terminal, a control circuit capable of operating based on a first power supply voltage, having an input terminal to which the detection voltage can be input, and capable of controlling an operation of the power conversion circuit based on the detection voltage, and a power supply circuit capable of generating the first power supply voltage and a second power supply voltage based on power input to the power input terminal. The sensor circuit includes a plurality of resistance elements provided in a path connecting the power output terminal and a reference node and connected in series via a first intermediate node and a second intermediate node connected to an input terminal of the control circuit, and a first diode having an anode connected to the first intermediate node and a cathode to which a second power supply voltage can be applied.SELECTED DRAWING: Figure 2

Description

[Technical Field]

[0001] The present invention relates to a power conversion device and a power conversion system for converting electric power. [Background technology]

[0002] In an electronic circuit, for example, an overcurrent or an overvoltage can damage the circuit. For example, Patent Document 1 discloses a switching device that protects the circuit when an overcurrent occurs. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] Japanese Patent Application Publication No. 8-271205 Summary of the Invention [Problem to be solved by the invention]

[0004] In electronic circuits, it is desirable to protect the circuits, and it is also expected that the circuits will be protected in power conversion devices.

[0005] It is desirable to provide a power converter and a power conversion system that can provide circuit protection. [Means for solving the problem]

[0006] A power conversion device according to one embodiment of the present invention includes a power input terminal, a power output terminal, a power conversion circuit, a sensor circuit, a control circuit, and a power supply circuit. The power conversion circuit is capable of performing power conversion based on power input to the power input terminal and outputting power generated by the power conversion operation from the power output terminal. The sensor circuit is capable of generating a detection voltage corresponding to the voltage at the power output terminal based on the voltage at the power output terminal. The control circuit is operable based on a first power supply voltage, has an input terminal to which the detection voltage can be input, and is capable of controlling the operation of the power conversion circuit based on the detection voltage. The power supply circuit is capable of generating a first power supply voltage and a second power supply voltage higher than the first power supply voltage based on the power input to the power input terminal. The sensor circuit includes multiple resistive elements and a first diode. The multiple resistive elements are provided in a path connecting the power output terminal and a reference node and are connected in series via a first intermediate node and a second intermediate node that is located closer to the reference node than the first intermediate node and connected to an input terminal of the control circuit. The first diode has an anode connected to the first intermediate node and a cathode to which the second power supply voltage can be applied.

[0007] A power conversion system according to one embodiment of the present invention includes a first battery, a capacitor, a first switch, a second switch, a power conversion device, and a second battery. The first battery has a first terminal and a second terminal. The capacitor has a first terminal and a second terminal. The first switch is provided in a path connecting the first terminal of the first battery and the first terminal of the capacitor. The second switch is provided in a path connecting the second terminal of the first battery and the second terminal of the capacitor. The power conversion device includes a power input terminal, a power output terminal, a power conversion circuit, a sensor circuit, a control circuit, and a power supply circuit. The power input terminal is connected to the capacitor. The power output terminal is connected to the second battery. The power conversion circuit is capable of performing power conversion based on power input to the power input terminal and is capable of outputting power generated by the power conversion operation from the power output terminal. The sensor circuit is capable of generating a detection voltage corresponding to the voltage at the power output terminal based on the voltage at the power output terminal. The control circuit is operable based on a first power supply voltage, has an input terminal to which the detection voltage can be input, and is capable of controlling the operation of the power conversion circuit based on the detection voltage. The power supply circuit is capable of generating a first power supply voltage and a second power supply voltage higher than the first power supply voltage based on power input to the power input terminal. The sensor circuit has a plurality of resistive elements and a first diode. The plurality of resistive elements are provided in a path connecting the power output terminal and a reference node, and are connected in series via a first intermediate node and a second intermediate node that is located closer to the reference node than the first intermediate node and is connected to an input terminal of the control circuit. The first diode has an anode connected to the first intermediate node and a cathode to which the second power supply voltage can be applied. [Effects of the Invention]

[0008] According to the power conversion device and power conversion system according to an embodiment of the present invention, it is possible to protect the circuit. [Brief explanation of the drawings]

[0009] [Figure 1] FIG. 1 is a circuit diagram showing an example of the configuration of a power conversion system according to an embodiment of the present invention. [Figure 2] FIG. 2 is a circuit diagram illustrating an example of the configuration of the sensor circuit shown in FIG. [Figure 3] FIG. 3 is an explanatory diagram illustrating an example of circuit constants of the sensor circuit shown in FIG. [Figure 4] FIG. 4 is an explanatory diagram illustrating an example of the operation of the sensor circuit shown in FIG. [Figure 5] FIG. 5 is an explanatory diagram illustrating another example of the operation of the sensor circuit shown in FIG. [Figure 6] FIG. 6 is a circuit diagram showing an example of the configuration of a sensor circuit according to a reference example. [Figure 7] FIG. 7 is a circuit diagram illustrating an example of the configuration of a sensor circuit according to a modified example. DETAILED DESCRIPTION OF THE INVENTION

[0010] Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings.

[0011] <Embodiment> [Configuration example] 1 shows an example of the configuration of a power conversion system 1 including a power conversion device according to an embodiment of the present invention. The power conversion system 1 includes a high-voltage battery BH, switches SW1 and SW2, a capacitor 9, a power conversion device 10, and a low-voltage battery BL. The power conversion system 1 is configured to convert power supplied from the high-voltage battery BH and supply the converted power to the low-voltage battery BL.

[0012] The high-voltage battery BH is configured to store power. In this example, the voltage of the high-voltage battery BH is 400 V. The high-voltage battery BH supplies power to the power conversion device 10 via switches SW1 and SW2.

[0013] The switches SW1 and SW2 are configured to supply power stored in the high-voltage battery BH to the power conversion device 10 when they are turned on. The switches SW1 and SW2 are configured using, for example, relays. When the switch SW1 is turned on, it connects the positive terminal of the high-voltage battery BH to the terminal T11 of the power conversion device 10. When the switch SW2 is turned on, it connects the negative terminal of the high-voltage battery BH to the terminal T12 of the power conversion device 10. The switches SW1 and SW2 are turned on and off based on instructions from a system control unit (not shown).

[0014] One end of the capacitor 9 is connected to the terminal T11 of the power conversion device 10 and the switch SW1, and the other end is connected to the terminal T12 of the power conversion device 10 and the switch SW2.

[0015] The power conversion device 10 is configured to convert power by stepping down the voltage supplied from the high-voltage battery BH and supply the converted power to the low-voltage battery BL. The power conversion device 10 has terminals T11 and T12, a switching circuit 12, a transformer 13, a rectifier circuit 14, a smoothing circuit 15, terminals T21 and T22, an auxiliary power supply circuit 18, a regulator 19, a sensor circuit 20, drive circuits 31 and 32, and a control circuit 33. The high-voltage battery BH, switches SW1 and SW2, capacitor 9, switching circuit 12, and drive circuit 31 constitute a primary circuit of the power conversion system 1, and the rectifier circuit 14, smoothing circuit 15, drive circuit 32, and low-voltage battery BL constitute a secondary circuit of the power conversion system 1. The switching circuit 12, transformer 13, rectifier circuit 14, and smoothing circuit 15 constitute a power conversion circuit 100.

[0016] Terminals T11 and T12 are configured to receive a voltage from a high-voltage battery BH when switches SW1 and SW2 are turned on. Within the power conversion device 10, terminal T11 is connected to a voltage line L11, and terminal T12 is connected to a reference voltage line L12. The voltage on voltage line L11 relative to the voltage on reference voltage line L12 is voltage VH.

[0017] The switching circuit 12 is configured to convert a DC voltage supplied from the high-voltage battery BH into an AC voltage. The switching circuit 12 is a full-bridge circuit and includes transistors S1 to S4. The transistors S1 to S4 are switching elements that perform switching operations based on gate signals GA to GD, respectively. The transistors S1 to S4 are configured using, for example, N-type field effect transistors (FETs). Each of the transistors S1 to S4 has a body diode. For example, the anode of the body diode of the transistor S1 is connected to the source of the body of the transistor S1, and the cathode is connected to the drain of the body of the transistor S1. The same applies to the transistors S2 to S4. Note that this configuration is not limited to this, and for example, a diode element may be externally connected between the drain and source of each of the transistors S1 to S4. Furthermore, although N-type field effect transistors are used in this example, any switching element may be used.

[0018] The transistor S1 is provided in a path connecting the voltage line L11 and the node N1, and is configured to connect the node N1 to the voltage line L11 when it is turned on. The drain of the transistor S1 is connected to the voltage line L11, the gate is supplied with a gate signal GA, and the source is connected to the node N1. The transistor S2 is provided in a path connecting the node N1 and the reference voltage line L12, and is configured to connect the node N1 to the reference voltage line L12 when it is turned on. The drain of the transistor S2 is connected to the node N1, the gate is supplied with a gate signal GB, and the source is connected to the reference voltage line L12.

[0019] The transistor S3 is provided in a path connecting the voltage line L11 and the node N2, and is configured to connect the node N2 to the voltage line L11 when turned on. The drain of the transistor S3 is connected to the voltage line L11, the gate is supplied with a gate signal GC, and the source is connected to the node N2. The transistor S4 is provided in a path connecting the node N2 and the reference voltage line L12, and is configured to connect the node N2 to the reference voltage line L12 when turned on. The drain of the transistor S4 is connected to the node N2, the gate is supplied with a gate signal GD, and the source is connected to the reference voltage line L12.

[0020] Transformer 13 is configured to insulate the primary side circuit from the secondary side circuit in terms of DC and connect them in terms of AC, convert the AC voltage supplied from the primary side circuit using the transformation ratio of transformer 13, and supply the converted AC voltage to the secondary side circuit. Transformer 13 has windings 13A and 13B. Winding 13A is a primary winding, and one end is connected to node N1 in switching circuit 12, and the other end is connected to node N2 in switching circuit 12. Winding 13B is a secondary winding, and one end is connected to node N4 (described later) in rectifier circuit 14, and the other end is connected to node N5 (described later) in rectifier circuit 14.

[0021] The rectifier circuit 14 is configured to rectify the AC voltage supplied from the winding 13B of the transformer 13. The rectifier circuit 14 is a full-bridge circuit and includes transistors S5 to S8. The transistors S5 to S8 are configured to perform switching operations based on gate signals GE and GF. Like the transistors S1 to S4 of the switching circuit 12, the transistors S5 to S8 are configured using, for example, N-type field effect transistors. Like the transistors S1 to S4, each of the transistors S5 to S8 has a body diode.

[0022] Transistor S5 is provided in a path connecting voltage line L21A and node N4, and is configured to connect node N4 to voltage line L21A when turned on. The drain of transistor S5 is connected to voltage line L21A, a gate signal GF is supplied to its gate, and a source is connected to node N4. Transistor S6 is provided in a path connecting node N4 and reference voltage line L22, and is configured to connect node N4 to reference voltage line L22 when turned on. The drain of transistor S6 is connected to node N4, a gate signal GE is supplied to its gate, and a source is connected to reference voltage line L22.

[0023] Transistor S7 is provided in a path connecting voltage line L21A and node N5, and is configured to connect node N5 to voltage line L21A when turned on. The drain of transistor S7 is connected to voltage line L21A, a gate signal GE is supplied to its gate, and a source is connected to node N5. Transistor S8 is provided in a path connecting node N5 and reference voltage line L22, and is configured to connect node N5 to reference voltage line L22 when turned on. The drain of transistor S8 is connected to node N5, a gate signal GF is supplied to its gate, and a source is connected to reference voltage line L22.

[0024] The smoothing circuit 15 is configured to smooth the voltage rectified by the rectifier circuit 14. The smoothing circuit 15 has a choke inductor 16 and a capacitor 17. One end of the choke inductor 16 is connected to the voltage line L21A, and the other end is connected to the voltage line L21B. One end of the capacitor 17 is connected to the voltage line L21B, and the other end is connected to the reference voltage line L22. Note that in this example, the choke inductor 16 is provided on the voltage lines L21A and L21B, but this is not limiting and instead, the choke inductor 16 may be provided on the reference voltage line L22, for example.

[0025] Terminals T21 and T22 are configured to supply the voltage generated by the power conversion device 10 to the low-voltage battery BL. Within the power conversion device 10, terminal T21 is connected to a voltage line L21B, and terminal T22 is connected to a reference voltage line L22. Furthermore, terminal T21 is connected to the positive terminal of the low-voltage battery BL, and terminal T22 is connected to the negative terminal of the low-voltage battery BL. The voltage on voltage line L21B relative to the voltage on reference voltage line L22 is voltage VL.

[0026] The auxiliary power supply circuit 18 is configured to generate a power supply voltage V10 based on the voltage VH at the terminals T11 and T12. In this example, the auxiliary power supply circuit 18 is configured using a flyback converter. In this example, the voltage of the power supply voltage V10 is 10 V.

[0027] The regulator 19 is configured to generate a power supply voltage VDD based on the power supply voltage V10. The power supply voltage VDD is 3.3 V in this example.

[0028] The sensor circuit 20 is configured to generate a voltage VNB corresponding to the voltage VL at the terminals T21 and T22, and to supply the voltage VNB to the control circuit 33.

[0029] Fig. 2 shows an example of the configuration of the sensor circuit 20. For convenience of explanation, in addition to the sensor circuit 20, Fig. 2 also shows the auxiliary power supply circuit 18, the regulator 19, the control circuit 33, and the low-voltage battery BL.

[0030] The sensor circuit 20 has resistance elements 21 to 23 and a diode 24. One end of the resistance element 21 is connected to the terminal T21, and the other end is connected to a node NA. One end of the resistance element 22 is connected to the node NA, and the other end is connected to a node NB. The node NB is connected to an input terminal Tin of the control circuit 33. One end of the resistance element 23 is connected to the node NB, and the other end is connected to a reference voltage line L22. The anode of the diode 24 is connected to the node NA, and a power supply voltage V10 is supplied to the cathode.

[0031] The drive circuit 31 (FIG. 1) is configured to generate gate signals GA to GD based on gate signals GA1 to GD1 supplied from the control circuit 33, respectively.

[0032] The drive circuit 32 is configured to generate gate signals GE and GF based on gate signals GE1 and GF1 supplied from the control circuit 33, respectively.

[0033] The control circuit 33 is configured to control the operation of the switching circuit 12 and the rectifier circuit 14 based on the voltage VNB supplied from the sensor circuit 20, thereby controlling the operation of the power conversion device 10. Specifically, the control circuit 33 generates gate signals GA1 to GF1 based on the voltage VNB, and performs PWM (Pulse Width Modulation) control using these gate signals GA1 to GF1, thereby controlling the operation of the power conversion device 10 so that the voltage VL becomes a predetermined voltage (12 V in this example). The control circuit 33 operates based on the power supply voltage VDD supplied from the regulator 19. The control circuit 33 is an integrated circuit and is configured using, for example, a microcontroller or the like.

[0034] 2, the control circuit 33 has diodes D1 and D2. The diodes D1 and D2 are so-called protection diodes that protect the control circuit 33. The anode of the diode D1 is connected to the input terminal Tin, and the cathode is connected to a power supply terminal of the control circuit 33. A power supply voltage VDD is supplied to this power supply terminal. The anode of the diode D2 is connected to a ground terminal of the control circuit 33, and the cathode is connected to the input terminal Tin. This ground terminal is connected to the reference voltage line L22.

[0035] The low-voltage battery BL (FIG. 1) is configured to store the power supplied from the power conversion device 10. The voltage of the low-voltage battery BL is 12 V in this example.

[0036] With this configuration, the power conversion system 1 performs a power conversion operation of converting the power supplied from the high-voltage battery BH and supplying the converted power to the low-voltage battery BL.

[0037] Here, the terminal T11 corresponds to a specific example of a "power input terminal" in an embodiment of the present disclosure. The power conversion circuit 100 corresponds to a specific example of a "power conversion circuit" in an embodiment of the present disclosure. The terminal T21 corresponds to a specific example of a "power output terminal" in an embodiment of the present disclosure. The sensor circuit 20 corresponds to a specific example of a "sensor circuit" in an embodiment of the present disclosure. The voltage VNB corresponds to a specific example of a "detection voltage" in an embodiment of the present disclosure. The control circuit 33 corresponds to a specific example of a "control circuit" in an embodiment of the present disclosure. The input terminal Tin corresponds to a specific example of an "input terminal" in an embodiment of the present disclosure. The auxiliary power supply circuit 18 and the regulator 19 correspond to a specific example of a "power supply circuit" in an embodiment of the present disclosure. The power supply voltage VDD corresponds to a specific example of a "first power supply voltage" in an embodiment of the present disclosure. The power supply voltage V10 corresponds to a specific example of a "second power supply voltage" in an embodiment of the present disclosure.

[0038] The node NA corresponds to a specific example of a "first intermediate node" in an embodiment of the present disclosure. The node NB corresponds to a specific example of a "second intermediate node" in an embodiment of the present disclosure. The reference voltage line L22 corresponds to a specific example of a "reference node" in an embodiment of the present disclosure. The resistive elements 21 to 23 correspond to a specific example of a "plurality of resistive elements" in an embodiment of the present disclosure. The resistive element 21 corresponds to a specific example of a "first resistive element" in an embodiment of the present disclosure. The resistive element 22 corresponds to a specific example of a "second resistive element" in an embodiment of the present disclosure. The resistive element 23 corresponds to a specific example of a "third resistive element" in an embodiment of the present disclosure. The diode 24 corresponds to a specific example of a "first diode" in an embodiment of the present disclosure.

[0039] The high-voltage battery BH corresponds to a specific example of a "first battery" in an embodiment of the present disclosure. The capacitor 9 corresponds to a specific example of a "capacitor" in an embodiment of the present disclosure. The switch SW1 corresponds to a specific example of a "first switch" in an embodiment of the present disclosure. The switch SW2 corresponds to a specific example of a "second switch" in an embodiment of the present disclosure. The low-voltage battery BL corresponds to a specific example of a "second battery" in an embodiment of the present disclosure.

[0040] [Actions and Actions] Next, the operation and function of the power conversion system 1 of this embodiment will be described.

[0041] (Overview of overall operation) First, referring to FIG. 1, an overview of the overall operation of the power conversion system 1 will be described. When the power conversion system 1 starts, the switches SW1 and SW2 first change from an OFF state to an ON state based on an instruction from a system control unit (not shown). This causes power to be supplied from the high-voltage battery BH to the terminals T11 and T12 of the power conversion device 10. The auxiliary power supply circuit 18 then generates a power supply voltage V10 based on the voltage VH, and the regulator 19 generates a power supply voltage VDD based on the power supply voltage V10. The control circuit 33 starts operating based on this power supply voltage VDD. The control circuit 33 controls the operation of the switching circuit 12 and the rectifier circuit 14 based on the voltage VNB supplied from the sensor circuit 20, thereby controlling the operation of the power conversion device 10. As a result, the power conversion device 10 converts the power supplied from the high-voltage battery BH and supplies the converted power to the low-voltage battery BL.

[0042] (Detailed operation) Next, the sensor circuit 20 will be described in detail.

[0043] 3 shows an example of circuit constants of the sensor circuit 20. The resistance value R21 of the resistive element 21 is 200 kΩ, the resistance value R22 of the resistive element 22 is 100 kΩ, and the resistance value R23 of the resistive element 23 is 39 kΩ. The forward voltage Vf of the diode 24 is 0.63 V.

[0044] 4 shows an example of the operation of the sensor circuit 20 when the switches SW1 and SW2 are on and the power conversion device 10 is performing a power conversion operation. Because the switches SW1 and SW2 are on, the terminals T11 and T12 of the power conversion device 10 are connected to the high-voltage battery BH. As a result, the auxiliary power supply circuit 18 generates a power supply voltage V10 based on the voltage VH, and the regulator 19 generates a power supply voltage VDD based on the power supply voltage V10. The power supply voltage V10 is 10 V, and the power supply voltage VDD is 3.3 V.

[0045] The voltage VL at the terminal T21 is 12 V. The voltages VNA and VNB expressed by the following equations are generated at the nodes NA and NB, respectively. VNA=VL×(R22+R23) / (R21+R22+R23) VNB = VL × (R23) / (R21 + R22 + R23) When the circuit constants shown in FIG. 3 are used, the voltage VNA is 4.9V and the voltage VNB is 1.38V.

[0046] In this case, the anode voltage of diode 24 is 4.9 V and the cathode voltage is 10 V, so diode 24 is in the OFF state. Therefore, as shown in FIG. 4, current flows from low-voltage battery BL through terminal T21, resistor element 21, resistor element 22, and resistor element 23 in this order. The current value of this current is 35 μA. Then, voltage VNB at node NB is input to input terminal Tin of control circuit 33. Based on this voltage VNB, control circuit 33 controls the operation of switching circuit 12 and rectifier circuit 14 so that voltage VL becomes 12 V.

[0047] Before the power conversion system 1 starts, the switches SW1 and SW2 are in the off state. Therefore, the terminals T11 and T12 of the power conversion device 10 are not connected to the high-voltage battery BH. On the other hand, the terminals T21 and T22 of the power conversion device 10 are connected to the low-voltage battery BL.

[0048] 5 shows an example of the operation of the sensor circuit 20 when the switches SW1 and SW2 are in the off state. Because the switches SW1 and SW2 are in the off state, no power is supplied from the high-voltage battery BH to the terminals T11 and T12 of the power conversion device 10. Therefore, the auxiliary power supply circuit 18 and the regulator 19 do not operate, and the power supply voltages V10 and VDD are both 0V.

[0049] In this case, the voltage at the cathode of diode 24 is 0V, so diode 24 is in the ON state. In this case, most of the current from low-voltage battery BL flows through terminal T21, resistor element 21, and diode 24 in that order, as shown in FIG. 5. The voltage VNA at node NA corresponds to the forward voltage Vf of diode 24 and is 0.63V. As a result, the voltage VNB at node NB is 0.18V. In sensor circuit 20, this voltage VNB can be kept below 0.3V, even when considering, for example, element variations and temperature fluctuations.

[0050] That is, in an integrated circuit, the rated input voltage may be the power supply voltage +0.3 V. In this sensor circuit 20, even if the power supply voltage VDD of the control circuit 33 is 0 V, the voltage VNB input to the input terminal Tin can be kept to 0.3 V or less, and the rated input voltage of the control circuit 33 can be satisfied.

[0051] For example, as shown in Fig. 6, when sensor circuit 20R is configured without diode 24, voltage VNB is 1.38 V. Therefore, when power supply voltage VDD of control circuit 33 is 0 V, the rated input voltage of control circuit 33 cannot be met. On the other hand, in sensor circuit 20 according to the present embodiment, diode 24 is provided, so the rated input voltage can be met.

[0052] Thus, the power conversion device 10 includes a power input terminal (terminal T11), a power output terminal (terminal T21), a power conversion circuit 100 capable of performing power conversion operation based on power input to the power input terminal (terminal T11) and outputting power generated by the power conversion operation from the power output terminal (terminal T21), a sensor circuit 20 capable of generating a detection voltage (voltage VNB) corresponding to the voltage at the power output terminal (terminal T21) based on the voltage at the power output terminal (terminal T21), a control circuit 33 capable of operating based on a first power supply voltage (power supply voltage VDD), having an input terminal Tin to which the detection voltage (voltage VNB) can be input, and capable of controlling the operation of the power conversion circuit 100 based on the detection voltage (voltage VNB), and a power supply circuit (auxiliary power supply circuit 18 and regulator 19) capable of generating the first power supply voltage (power supply voltage VDD) and a second power supply voltage (power supply voltage V10) higher than the first power supply voltage based on the power input terminal (terminal T11). The sensor circuit 20 is provided on a path connecting the power output terminal (terminal T21) and the reference node (reference voltage line L22), and includes a plurality of resistor elements (resistor elements 21-23) connected in series via a first intermediate node (node ​​NA) and a second intermediate node (node ​​NB) that is located closer to the reference node than the first intermediate node and connected to an input terminal Tin of the control circuit 33, and a first diode (diode 24) having an anode connected to the first intermediate node and a cathode to which a second power supply voltage (power supply voltage V10) can be applied. As a result, in the power conversion device 10, as described above, a voltage exceeding the rated voltage is not input to the input terminal Tin of the control circuit 33, thereby protecting the circuit.

[0053] In the power conversion device 10, the first diode (diode 24) can be turned off while the power supply circuit (auxiliary power supply circuit 18 and regulator 19) is operating, and can be turned on while the power supply circuit (auxiliary power supply circuit 18 and regulator 19) is not operating. For example, as shown in FIG. 4, when switches SW1 and SW2 are on, the auxiliary power supply circuit 18 generates a power supply voltage V10 based on voltage VH, and the regulator 19 generates a power supply voltage VDD based on power supply voltage V10. In this way, when the auxiliary power supply circuit 18 and regulator 19 are operating, the diode 24 is turned off. Also, for example, as shown in FIG. 5, when switches SW1 and SW2 are off, the auxiliary power supply circuit 18 and regulator 19 are not operating. In this case, the diode 24 is turned on. As a result, in the power conversion device 10, as described above, a voltage exceeding the rated voltage is not input to the input terminal Tin of the control circuit 33, thereby protecting the circuit.

[0054] [effect] As described above, this embodiment includes a power input terminal, a power output terminal, a power conversion circuit capable of performing power conversion based on power input to the power input terminal and outputting power generated by the power conversion from the power output terminal, a sensor circuit 20 capable of generating a detection voltage corresponding to the voltage at the power output terminal based on the voltage at the power output terminal, a control circuit capable of operating based on a first power supply voltage, having an input terminal Tin to which the detection voltage can be input and capable of controlling the operation of the power conversion circuit based on the detection voltage, and a power supply circuit capable of generating a first power supply voltage and a second power supply voltage higher than the first power supply voltage based on the power input to the power input terminal. The sensor circuit is provided in a path connecting the power output terminal and a reference node, and includes a first intermediate node and a second intermediate node located closer to the reference node than the first intermediate node and connected to an input terminal of the control circuit 33. The first intermediate node and the second intermediate node are connected to a first diode having an anode connected to the first intermediate node and a cathode to which the second power supply voltage can be applied. This allows for circuit protection.

[0055] In this embodiment, the first diode can be turned off during the period when the power supply circuit is operating, and can be turned on during the period when the power supply circuit is not operating, thereby enabling protection of the circuit.

[0056] [Variation 1] In the above embodiment, the sensor circuit 20 includes the resistor elements 21 to 23 and the diode 24. However, this is not limiting. Alternatively, another diode may be included, as in the power conversion device 10B shown in FIG. 7. The power conversion device 10B includes a sensor circuit 20B. The sensor circuit 20B includes a diode 25B. The anode of the diode 25B is connected to the reference voltage line L22, and the cathode is connected to the node NA. This configuration can reduce the effect of a reverse current through the diode 24 on the detection accuracy of the voltage VL. For example, as shown in FIG. 4, when the power conversion device 10 performs a power conversion operation, a reverse current flowing from the cathode to the anode of the diode 24 may affect the voltage VNB at the node NB. In the sensor circuit 20B, the diode 25B is provided, and a reverse current flows from the cathode to the anode of the diode 25B. This reduces the effect of the reverse current through the diode 24 on the voltage VNB.

[0057] [Variation 2] In the above embodiment, the switches SW1 and SW2 are provided, and the power conversion device 10 performs a power conversion operation after the switches SW1 and SW2 are turned on. In this manner, before the switches SW1 and SW2 are turned on, for example, a so-called pre-charge operation may be performed to charge the capacitor 9 by supplying power from the low-voltage battery BL to the primary side circuit via the transformer 13. This allows the power conversion device 10 to suppress an inrush current flowing from the high-voltage battery BH to the capacitor 9 when the switches SW1 and SW2 are turned on.

[0058] [Variation 3] In the above embodiment, the power conversion device 10 has the circuit configuration shown in FIG. 1, but is not limited to this. For example, the switching circuit 12 of the primary side circuit may be a half-bridge type circuit. Furthermore, the rectifier circuit 14 of the secondary side may be a rectifier circuit using diodes. Furthermore, the power conversion device 10 is an isolated circuit having a transformer 13, but is not limited to this and may instead be a non-isolated circuit.

[0059] [Other variations] Two or more of these variations may also be combined.

[0060] Although the present invention has been described above by way of embodiments and modifications, the present invention is not limited to these embodiments and can be modified in various ways.

[0061] For example, the circuit constants shown in FIG. 3 are merely examples and can be changed as appropriate.

[0062] The effects described in this specification are merely examples, and the effects of the present disclosure are not limited to the effects described in this specification. Therefore, other effects may be obtained with respect to the present disclosure.

[0063] Furthermore, the present disclosure may take the following aspects.

[0064] (1) a power input terminal; a power output terminal; a power conversion circuit capable of performing a power conversion operation based on power input to the power input terminal and capable of outputting power generated by the power conversion operation from the power output terminal; a sensor circuit capable of generating a detection voltage corresponding to the voltage at the power output terminal based on the voltage at the power output terminal; a control circuit operable based on a first power supply voltage, having an input terminal to which the detection voltage can be input, and capable of controlling the operation of the power conversion circuit based on the detection voltage; a power supply circuit capable of generating the first power supply voltage and a second power supply voltage higher than the first power supply voltage based on power input to the power input terminal; Equipped with The sensor circuit a first intermediate node provided in a path connecting the power output terminal and a reference node, the second intermediate node being located closer to the reference node than the first intermediate node and connected to the input terminal of the control circuit; and a first diode having an anode connected to the first intermediate node and a cathode to which the second power supply voltage can be applied; have Power conversion device. (2) The first diode can be turned off during a period when the power supply circuit is operating, and can be turned on during a period when the power supply circuit is not operating. The power conversion device according to (1) above. (3) The sensor circuit further includes a second diode having an anode connected to the reference node and a cathode connected to the first intermediate node. The power conversion device according to (1) or (2). (4) The plurality of resistive elements are a first resistive element having one end connected to the power output terminal and the other end connected to the first intermediate node; a second resistive element having one end connected to the first intermediate node and the other end connected to the second intermediate node; a third resistive element having one end connected to the second intermediate node and the other end connected to the reference node; Contains The power conversion device according to any one of (1) to (3). (5) a first battery having a first terminal and a second terminal; a capacitor having a first terminal and a second terminal; a first switch provided in a path connecting the first terminal of the first battery and the first terminal of the capacitor; a second switch provided in a path connecting the second terminal of the first battery and the second terminal of the capacitor; a power conversion device; Second battery and Equipped with The power conversion device is a power input terminal connected to the capacitor; a power output terminal connected to the second battery; a power conversion circuit capable of performing a power conversion operation based on power input to the power input terminal and capable of outputting power generated by the power conversion operation from the power output terminal; a sensor circuit capable of generating a detection voltage corresponding to the voltage at the power output terminal based on the voltage at the power output terminal; a control circuit operable based on a first power supply voltage, having an input terminal to which the detection voltage can be input, and capable of controlling the operation of the power conversion circuit based on the detection voltage; a power supply circuit capable of generating the first power supply voltage and a second power supply voltage higher than the first power supply voltage based on power input to the power input terminal; and The sensor circuit a first intermediate node provided in a path connecting the power output terminal and a reference node, the second intermediate node being located closer to the reference node than the first intermediate node and connected to the input terminal of the control circuit; and a first diode having an anode connected to the first intermediate node and a cathode to which the second power supply voltage can be applied; have Power conversion systems. [Explanation of symbols]

[0065] 1...power conversion system, 9...capacitor, 10, 10B...power conversion device, 12...switching circuit, 13...transformer, 13A, 13B...winding, 14...rectifier circuit, 15...smoothing circuit, 16...choke inductor, 17...capacitor, 18...auxiliary power supply circuit, 19...regulator, 20, 20B...sensor circuit, 21 to 23...resistance elements, 24, 25B...diode, 31, 32...drive circuit, 33...control circuit, 100...power conversion circuit, BH...high-voltage battery, BL...low-voltage battery Battery, D1, D2...diodes, GA~GF, GA1~GF1...gate signals, L11...voltage line, L12...reference voltage line, L21A, L21B...voltage line, L22...reference voltage line, NA...node, NB...node, R21~R23...resistance value, S1~S8...transistors, SW1, SW2...switches, T11, T12...terminals, T21, T22...terminals, Tin...input terminal, V10...power supply voltage, VDD...power supply voltage, VH, VL, VNA, VNB...voltage, Vf...forward voltage.

Claims

1. a power input terminal; a power output terminal; a power conversion circuit capable of performing a power conversion operation based on power input to the power input terminal and capable of outputting power generated by the power conversion operation from the power output terminal; a sensor circuit capable of generating a detection voltage corresponding to the voltage at the power output terminal based on the voltage at the power output terminal; a control circuit operable based on a first power supply voltage, having an input terminal to which the detection voltage can be input, and capable of controlling the operation of the power conversion circuit based on the detection voltage; a power supply circuit capable of generating the first power supply voltage and a second power supply voltage higher than the first power supply voltage based on power input to the power input terminal; Equipped with The sensor circuit a plurality of resistance elements connected in series via a first intermediate node and a second intermediate node that is provided in a path connecting the power output terminal and a reference node, the second intermediate node being located closer to the reference node than the first intermediate node and connected to the input terminal of the control circuit; a first diode having an anode connected to the first intermediate node and a cathode to which the second power supply voltage can be applied; have Power conversion device.

2. The first diode can be turned off during a period when the power supply circuit is operating, and can be turned on during a period when the power supply circuit is not operating. The power conversion device according to claim 1 .

3. The sensor circuit further includes a second diode having an anode connected to the reference node and a cathode connected to the first intermediate node. The power conversion device according to claim 1 .

4. The plurality of resistive elements are a first resistive element having one end connected to the power output terminal and the other end connected to the first intermediate node; a second resistive element having one end connected to the first intermediate node and the other end connected to the second intermediate node; a third resistive element having one end connected to the second intermediate node and the other end connected to the reference node; Contains The power conversion device according to any one of claims 1 to 3.

5. a first battery having a first terminal and a second terminal; a capacitor having a first terminal and a second terminal; a first switch provided in a path connecting the first terminal of the first battery and the first terminal of the capacitor; a second switch provided in a path connecting the second terminal of the first battery and the second terminal of the capacitor; a power conversion device; a second battery; Equipped with The power conversion device is a power input terminal connected to the capacitor; a power output terminal connected to the second battery; a power conversion circuit capable of performing a power conversion operation based on power input to the power input terminal and capable of outputting power generated by the power conversion operation from the power output terminal; a sensor circuit capable of generating a detection voltage corresponding to the voltage at the power output terminal based on the voltage at the power output terminal; a control circuit operable based on a first power supply voltage, having an input terminal to which the detection voltage can be input, and capable of controlling the operation of the power conversion circuit based on the detection voltage; a power supply circuit capable of generating the first power supply voltage and a second power supply voltage higher than the first power supply voltage based on power input to the power input terminal; and The sensor circuit a plurality of resistance elements connected in series via a first intermediate node and a second intermediate node that is provided in a path connecting the power output terminal and a reference node, the second intermediate node being located closer to the reference node than the first intermediate node and connected to the input terminal of the control circuit; a first diode having an anode connected to the first intermediate node and a cathode to which the second power supply voltage can be applied; have Power conversion systems.

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