Current detection device, power supply device, and current detection method

Abstract

To accurately detect current even when a switching unit is intermittently operated.SOLUTION: A current detector comprises: a first Rogowskii coil detecting current flowing through a first switching element; a second Rogowskii coil detecting current flowing through a second switching element; a first integration circuit having a reset function and integrating output of the first Rogowskii coil to output a first detection signal; a second integration circuit having a reset function and integrating the output of the second Rogowskii coil to output a second detection signal; a detection processing unit detecting current flowing through the switching unit on the basis of the first detection signal and the second detection signal; and a reset generating unit that in an intermittent operation mode for intermittently operating the switching unit, fixes the first integration circuit and the second integration circuit in a reset state in a stop period for bringing both the first switching element and the second switching element into a non-conduction state.SELECTED DRAWING: Figure 2

Description

[Technical field]

[0001] The present invention relates to a current detection device, a power supply device, and a current detection method. [Background technology]

[0002] In recent years, a current detection device that detects a current using a Rogowski coil has become known (see Patent Document 1). In such a current detection device, the output of the Rogowski coil is integrated to detect the current. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] Republished WO2017 / 150726 Summary of the Invention [Problem to be solved by the invention]

[0004] In the conventional current detection device described above, in order to accurately detect a current, it is necessary to reset the integrating circuit before detecting the current. When the conventional current detection device is used in a power supply device equipped with a switching unit, such as a DC-DC converter, the integrating circuit is reset for each switching cycle, and a reset signal is generated based on a control signal from the switching unit. However, in conventional current detection devices, for example, when the power supply device operates the switching unit intermittently when the load is low, a reset is not performed during the period when operation is stopped due to the intermittent operation, and an offset voltage is generated in the integration circuit, which can reduce the accuracy of the detected current value.

[0005] The present invention has been made to solve the above problems, and its purpose is to provide a current detection device, a power supply device, and a current detection method that are capable of detecting current with high accuracy even when a switching unit is operated intermittently. [Means for solving the problem]

[0006] In order to solve the above problem, one aspect of the present invention is a current detection device having a first switching element and a second switching element connected in series, and detecting a current flowing through a switching unit that operates a power supply, the current detection device comprising: a first Rogowski coil that detects the current flowing through the first switching element; a second Rogowski coil that detects the current flowing through the second switching element; a first integration circuit having a reset function that integrates the output of the first Rogowski coil and outputs a first detection signal; a second integration circuit having a reset function that integrates the output of the second Rogowski coil and outputs a second detection signal; a detection processing unit that detects the current flowing through the switching unit based on the first detection signal and the second detection signal; and a reset generation unit that fixes the first integration circuit and the second integration circuit to a reset state during the entire stop period in which both the first switching element and the second switching element are made non-conductive when the switching unit is in an intermittent operation mode in which it operates intermittently. According to another aspect of the present invention, in the current detection device, the reset generation unit includes a first reset switch that resets a first reset signal that resets the first integration circuit during the entire stop period of the intermittent operation mode, and a second reset switch that resets the first integration circuit during the entire stop period of the intermittent operation mode. 2 The present invention is characterized by comprising a second reset switch that sets a second reset signal, which resets an integrating circuit, to a reset state, and a reset control unit that controls the first reset switch and the second reset switch to fix the first reset signal and the second reset signal to the reset state during the entire stop period of the intermittent operation mode.

[0007] Moreover, one aspect of the present invention is characterized in that, in the above-mentioned current detection device, when in a continuous operation mode in which the first switching element and the second switching element are alternately brought into a conductive state in a continuous and periodic manner, the reset generation unit generates a first reset signal that resets the first integrator circuit before the first switching element becomes conductive and brings the period in which the first switching element is in a conductive state into a reset release state, and a second reset signal that resets the second integrator circuit before the second switching element becomes conductive and brings the period in which the second switching element is in a conductive state into a reset release state.

[0008] Moreover, one aspect of the present invention is characterized in that, in the above-mentioned current detection device, the reset generation unit generates the first reset signal and the second reset signal based on a first control signal that puts the first switching element into a conductive state and a second control signal that puts the second switching element into a conductive state.

[0009] In addition, one aspect of the present invention is characterized in that, in the above-mentioned current detection device, the reset generation unit includes a first reset switch that sets the first reset signal to a reset state and a second reset switch that sets the second reset signal to a reset state during the stop period of the intermittent operation mode.

[0010] Another aspect of the present invention is a power supply device comprising the current detection device described above, the switching unit, and a power supply control unit that controls the switching unit based on the current value detected by the current detection device.

[0011] In one aspect of the present invention, in the power supply device described above, the power supply control unit switches the power supply to the intermittent operation mode when the current value is equal to or lower than a predetermined current value.

[0012] Another aspect of the present invention is a current detection method for detecting a current flowing in a switching unit having a first switching element and a second switching element connected in series and operating a power supply device, the method including a first integration step in which a first integration circuit having a reset function integrates an output of a first Rogowski coil that detects a current flowing in the first switching element and outputs a first detection signal, a second integration step in which a second integration circuit having a reset function integrates an output of a second Rogowski coil that detects a current flowing in the second switching element and outputs a second detection signal, a detection processing step in which a detection processing unit detects the current flowing in the switching unit based on the first detection signal and the second detection signal, and a stop period in which a reset generation unit makes both the first switching element and the second switching element non-conductive when the switching unit is in an intermittent operation mode in which the switching unit is operated intermittently. During the entire period and a reset generating step of fixing the first integrating circuit and the second integrating circuit in a reset state. Effect of the Invention

[0013] According to the present invention, a first integrating circuit having a reset function integrates the output of the first Rogowski coil to output a first detection signal, and a second integrating circuit having a reset function integrates the output of the second Rogowski coil to output a second detection signal. A detection processing unit detects a current flowing through a switching unit based on the first detection signal and the second detection signal. When an intermittent operation mode is selected for intermittently operating the switching unit, a reset generating unit fixes the first integrating circuit and the second integrating circuit in a reset state during a stop period in which both the first switching element and the second switching element are in a non-conductive state. Since the first integrating circuit and the second integrating circuit are fixed in a reset state during a stop period in the intermittent operation mode, the current detecting device can reduce the influence of the offset voltage of the first integrating circuit and the second integrating circuit. Therefore, the current detecting device can detect a current with high accuracy even when the switching unit is intermittently operated. [Brief description of the drawings]

[0014] [Figure 1] 1 is a block diagram showing an example of a power supply device according to an embodiment of the present invention; [Diagram 2] 1 is a block diagram showing an example of a current detection device according to an embodiment of the present invention; [Diagram 3] FIG. 2 is a circuit diagram illustrating an example of an integrating circuit according to the present embodiment. [Figure 4] 5 is a flowchart showing an example of a process for switching an operation mode of the power supply device according to the present embodiment. [Diagram 5] 5A to 5C are diagrams illustrating the operation mode switching process and current detection process of the power supply device according to the present embodiment. [Figure 6] 5 is a flowchart showing an example of the operation of the current detection device according to the present embodiment. [Figure 7] 5 is a timing chart showing an example of the operation of the current detection device according to the present embodiment. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0015] DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS A current detection device, a power supply device, and a current detection method according to an embodiment of the present invention will be described below with reference to the drawings.

[0016] FIG. 1 is a block diagram showing an example of a power supply device 1 according to the present embodiment. As shown in FIG. 1, the power supply device 1 includes switching elements (21, 22), Rogowski coils (11, 12), a detection processing unit 13, capacitors (14, 16), a coil 15, resistors (17, 18, 23, 24), and a control IC (Integrated Circuit) 30.

[0017] The power supply device 1 is, for example, a switching power supply device such as a DC-DC converter, and has a power supply line L1, a ground line L2, and a power output line L3. The power supply line L1 is a power line to which DC power is supplied from a DC power source such as a battery, the ground line L2 is a ground power line connected to the ground, and the power output line L3 is an output line that outputs DC power obtained by converting the DC power supplied to the power supply line L1.

[0018] The capacitor 14 is a smoothing capacitor that is connected between the power supply line L1 and the ground line L2 and smoothes the DC voltage between the power supply line L1 and the ground line L2. A switching element 21 (an example of a first switching element) and a switching element 22 (an example of a second switching element) are connected in series between a power supply line L1 and a ground line L2, and constitute a switching section 20 that operates the power supply device 1.

[0019] The switching element 21 is, for example, an N-type MOSFET (Metal-Oxide-Semiconductor Field-Effect Transistor), with a source terminal connected to the node N1, a drain terminal connected to the power supply line L1, and a gate terminal (control terminal) connected to a signal line for a control signal G1. The switching element 21 is a High-side switching element.

[0020] The switching element 22 is, for example, an N-type MOSFET, with a source terminal connected to the ground line L2, a drain terminal connected to the node N1, and a gate terminal (control terminal) connected to a signal line for a control signal G2. The switching element 21 is a low-side switching element. The switching element 21 and the switching element 22 constitute a switching section 20 which will be described later.

[0021] The Rogowski coil 11 (an example of a first Rogowski coil) is connected to a path through which a current flows from the power supply line L1 to the switching element 21, for example, and detects the current flowing through the switching element 21. The Rogowski coil 12 (an example of a second Rogowski coil) is connected to a path through which a current flows from the switching element 22 to the ground line L2, for example, and detects the current flowing through the switching element 22.

[0022] The coil 15 is a coil used in a chopper circuit, and is connected between the node N1 and the power supply output line L3. The capacitor 16 is a smoothing capacitor that is connected between the power supply output line L3 and the ground line L2 and smoothes the DC voltage that the power supply device 1 outputs. The switching unit 20 (switching element 21 and switching element 22), the coil 15, and the capacitor 16 function as a step-down chopper circuit.

[0023] Resistors 17 and 18 are connected in series between the power output line L3 and the ground line L2, and supply to the control IC the voltage of node N2, which is the resistively divided output voltage of the power supply device 1. Resistor 17 is connected between the power output line L3 and node N2, and resistor 18 is connected between node N2 and the ground line L2.

[0024] The detection processing unit 13 detects a current flowing through the switching unit 20 based on a detection signal (first detection signal) obtained by integrating the output of the Rogowski coil 11 and a detection signal (second detection signal) obtained by integrating the output of the Rogowski coil 12. The detection processing unit 13 outputs the detected current value to the control IC 30 as a detected current value IFB. Details of the configuration of the detection processing unit 13 will be described later with reference to FIG. 2.

[0025] The control IC 30 is, for example, an LSI such as a processor including a CPU (Central Processing Unit), and performs overall control of the power supply device 1. The control IC 30 outputs control signals (G1, G2) that control the switching unit 20 based on the voltage (detected voltage) of the node N2 and the detected current value IFB detected by the detection processing unit 13 described above.

[0026] A control signal G1 output by the control IC 30 is supplied to the gate terminal of the switching element 21 via a resistor 23. A control signal G2 output by the control IC 30 is supplied to the gate terminal of the switching element 22 via a resistor 24. The control IC 30 also generates a reset signal for the integrating circuits 40 (40-1, 40-2) described later. The configuration of the control IC 30 will be described in detail later with reference to FIG.

[0027] In this embodiment, a part of the control IC 30, the Rogowski coil 11, the Rogowski coil 12, and the detection processing unit 13 correspond to the current detection device 10. Next, a detailed configuration of the current detection device 10 will be described with reference to FIG.

[0028] FIG. 2 is a block diagram showing an example of a current detection device 10 according to the present embodiment. 2, the current detection device 10 includes a Rogowski coil 11, a Rogowski coil 12, a detection processing unit 13, and a reset generation unit 50. The reset generation unit 50 is a part of the control IC 30.

[0029] The Rogowski coil 11 supplies an output for detecting a current flowing through a high-side switching element 21 of the switching unit 20 to the detection processing unit 13. The Rogowski coil 12 supplies an output for detecting a current flowing through a low-side switching element 22 of the switching unit 20 to the detection processing unit 13.

[0030] The detection processing unit 13 includes an integrating circuit 40-1, an integrating circuit 40-2, and an adder 131. In this embodiment, the integrating circuit 40-1 and the integrating circuit 40-2 have the same configuration, and will be described as the integrating circuit 40 when referring to any integrating circuit included in the power supply device 1 (current detection device 10) or when no particular distinction is made.

[0031] The integrating circuit 40-1 (an example of a first integrating circuit) has a reset function, and integrates the output of the Rogowski coil 11 to output a detection signal (a first detection signal). Moreover, the integrating circuit 40-2 (an example of a second integrating circuit) has a reset function, and integrates the output of the Rogowski coil 12 to output a detection signal (a second detection signal). Now, with reference to FIG. 3, a detailed configuration of the integrating circuit 40 will be described.

[0032] FIG. 3 is a circuit diagram showing an example of the integrating circuit 40 in this embodiment. As shown in FIG. 3, the integrating circuit 40 includes a resistor 41, an operational amplifier 42, a capacitor 43, and a switch 44. The resistor 41 is connected between one end of the Rogowski coil 11 (12) and the inverting input terminal of the operational amplifier 42. In addition, the capacitor 43 is connected between the inverting input terminal (node ​​N5) of the operational amplifier 42 and the output terminal (node ​​N6) of the operational amplifier 42.

[0033] The operational amplifier 42 functions as an integrating circuit by being connected to a resistor 41 and a capacitor 43. One end of the Rogowski coil 11(12) is connected to the inverting input terminal of the operational amplifier 42 via the resistor 41, and the other end of the Rogowski coil 11(12) is connected to the non-inverting input. The operational amplifier 42 receives the output of the Rogowski coil 11(12) as an input signal (IN), and outputs an output signal (OUT) obtained by integrating the output of the Rogowski coil 11(12). The output signal (OUT) of the integrating circuit 40-1 corresponds to the first detection signal described above, and the output signal (OUT) of the integrating circuit 40-2 corresponds to the second detection signal described above.

[0034] The switch 44 is connected in parallel with the capacitor 43 between the inverting input terminal (node ​​N4) of the operational amplifier 42 and the output terminal (node ​​N5) of the operational amplifier 42. The switch 44 is a switch that resets the output potential of the integrating circuit 40, and the conductive state of the switch 44 is controlled by, for example, a pulse signal of the control signal S. Note that the switch 44 is controlled to the conductive state (ON state) when the integrating circuit 40 is reset.

[0035] When the switch 44 is controlled to a non-conductive state (off state) by the control signal S, the integration circuit 40 functions as an integration circuit. Furthermore, the control signal S is controlled so as to reset the integrating circuit 40 when the switching of the above-mentioned switching elements 21 and 22 is stopped, and so as to operate the integrating circuit 40 when the switching of the switching elements 21 and 22 is being switched. Here, the control signal S of the integrating circuit 40-1 corresponds to a High-side reset signal RST_H (first reset signal), and the control signal S of the integrating circuit 40-2 corresponds to a Low-side reset signal RST_L (second reset signal).

[0036] For example, the integration circuit 40-1 is in the reset state when the reset signal RST_H (first reset signal) generated by the reset generation unit 50 is in the low state, and the integration circuit 40-2 is in the reset state when the reset signal RST_L (second reset signal) generated by the reset generation unit 50 is in the low state.

[0037] Returning to the explanation of FIG. 2, the adder 131 adds the first detection signal output by the integrating circuit 40-1 and the second detection signal output by the integrating circuit 40-2 to generate a detection current value (detection current value IFB).

[0038] The control IC 30 includes a buffer circuit 31 and a buffer circuit 32, a control unit 33, an inverter circuit 51 and an inverter circuit 53, resistors 52 and 54, and reset switches 55 and 56. The control unit 33 also includes a power control unit 331 and a reset control unit 332. The inverter circuits 51 and 53, the resistors 52 and 54, the reset switches 55 and 56, and the reset control unit 332 correspond to the reset generation unit 50.

[0039] The buffer circuit 31 is, for example, a driver circuit that drives the gate terminal of the switching element 21. The buffer circuit 31 outputs a control signal G1 that controls the switching element 21 based on a control signal S1 output by the control unit 33.

[0040] The buffer circuit 32 is, for example, a driver circuit that drives the gate terminal of the switching element 22. The buffer circuit 32 outputs a control signal G2 that controls the switching element 22 based on a control signal S2 output by the control unit 33.

[0041] The inverter circuit 51 is, for example, an inversion circuit that generates a reset signal RST_L for the integrating circuit 40-2. The inverter circuit 51 generates a low-side reset signal RST_L that is the logical inversion of the control signal S1 output by the control unit 33. The inverter circuit 51 supplies the reset signal RST_L to the terminal of the control signal S of the integrating circuit 40-2 via a resistor 52.

[0042] Resistor 52 is connected between the output terminal of inverter circuit 51 and node N3, and limits the current so that an excessive load is not applied to the output of inverter circuit 51 when reset switch 55 is turned on.

[0043] The inverter circuit 53 is, for example, an inversion circuit that generates a reset signal RST_H for the integrating circuit 40-1. The inverter circuit 53 generates a High-side reset signal RST_H by logically inverting the control signal S2 output by the control unit 33. The inverter circuit 53 supplies the reset signal RST_H to the terminal of the control signal S of the integrating circuit 40-1 via a resistor 54.

[0044] The resistor 54 is connected between the output terminal of the inverter circuit 53 and a node N4, and limits the current so that an excessive load is not applied to the output of the inverter circuit 53 when the reset switch 56 is turned on.

[0045] The reset switch 55 is, for example, an N-type MOSFET, with a source terminal connected to the ground line L2, a drain terminal connected to a node N3, and a gate terminal (control terminal) connected to a signal line for a control signal S3 of the control unit 33. When the reset switch 55 becomes conductive, it fixes the reset signal RST_H to a low state, and fixes the integration circuit 40-1 in a reset state.

[0046] The reset switch 56 is, for example, an N-type MOSFET, with a source terminal connected to the ground line L2, a drain terminal connected to a node N4, and a gate terminal (control terminal) connected to a signal line for a control signal S4 of the control unit 33. When the reset switch 56 becomes conductive, it fixes the reset signal RST_L to a low state, and fixes the integration circuit 40-2 in a reset state.

[0047] The power supply control unit 331 controls the switching unit 20 based on the current value (detected current value IFB) detected by the current detection device 10. The power supply control unit 331 generates a control signal S1 and a control signal S2 for switching the switching unit 20 so that the output voltage (node ​​N2) becomes a predetermined voltage based on, for example, the detected current value IFB and the voltage of node N2 (corresponding to the output voltage value). The power supply control unit 331 generates the control signal S1 for putting the switching element 21 into a conductive state, and generates the control signal S2 for putting the switching element 22 into a conductive state.

[0048] Moreover, the power supply control unit 331 has a normal operation mode and an intermittent operation mode when controlling the switching unit 20. Here, the normal operation mode is an operation mode in which the switching element 21 and the switching element 22 are alternately turned on in a continuous and periodic manner, and the intermittent operation mode is an operation mode in which the switching unit 20 is operated intermittently. The power supply control unit 331 controls the switching of the switching unit 20 in the intermittent operation mode when the detected current (detected current value IFB) detected by the current detection device 10 is equal to or smaller than a predetermined current value Ith. Moreover, the power supply control unit 331 controls the switching of the switching unit 20 in the continuous operation mode when the detected current (detected current value IFB) detected by the current detection device 10 is larger than the predetermined current value Ith.

[0049] The reset control unit 332 controls the reset signals RST_H and RST_L. In the intermittent operation mode, the reset control unit 332 fixes the integrating circuits 40-1 and 40-2 to a reset state during a stop period in which both the switching element 21 and the switching element 22 are in a non-conductive state. During the stop period in the intermittent operation mode, the reset control unit 332 sets the control signals S3 and S4 to a High state, and sets the reset switches 55 and 56 to a conductive state.

[0050] Furthermore, in the normal operation mode, the reset control unit 332 sets the control signals S3 and S4 to a low state, and sets the reset switches 55 and 56 to a non-conductive state. As a result, the reset signals RST_H and RST_L are controlled by the control signals S2 and S1.

[0051] In this way, the reset generation unit 50 generates the reset signals RST_H and RST_L based on the control signal S1 (first control signal) that puts the switching element 21 into a conductive state, and the control signal S2 (second control signal) that puts the switching element 22 into a conductive state.

[0052] Next, the operation of the power supply device 1 and the current detection device 10 according to the present embodiment will be described with reference to the drawings. FIG. 4 is a flowchart showing an example of the operation mode switching process of the power supply device 1 according to this embodiment.

[0053] 4, the power supply control unit 331 of the power supply device 1 first determines whether the detected current is equal to or less than a predetermined current value Ith (step S101). The power supply control unit 331 determines whether the detected current value IFB detected by the current detection device 10 is equal to or less than the predetermined current value Ith. If the detected current value IFB is equal to or less than the predetermined current value Ith (step S101: YES), the power supply control unit 331 advances the process to step S102. If the detected current value IFB is greater than the predetermined current value Ith (step S101: NO), the power supply control unit 331 advances the process to step S103.

[0054] In step S102, the power supply control unit 331 changes to the intermittent operation mode. After changing to the intermittent operation mode, the power supply control unit 331 performs control to intermittently operate the switching unit 20. After the process of step S102, the process returns to step S101.

[0055] In step S103, the power supply control unit 331 changes to the continuous operation mode. After changing to the continuous operation mode, the power supply control unit 331 controls the switching elements 21 and 22 to be alternately turned on in a continuous and periodic manner. After the process of step S103, the process returns to step S101.

[0056] Next, the operation mode switching process of the power supply device 1 and the current detection process of the current detection device 10 will be described with reference to FIG. FIG. 5 is a diagram illustrating the operation mode switching process and current detection process of the power supply device 1 according to this embodiment.

[0057] 5(a) shows an example of a detection current of the current detection device 10 in the continuous operation mode. In the continuous operation mode, the power supply control unit 331 controls the switching element 21 and the switching element 22 to be alternately turned on, thereby operating the step-down chopper circuit including the coil 15.

[0058] 5(a), the waveform IH is the current detection waveform of the current detection device 10 when the switching element 21 is in the conductive state, and shows the portion detected by the Rogowski coil 11. The waveform IH here shows the waveform of the first detection signal generated by the integrating circuit 40-1. The waveform IL is a current detection waveform of the current detection device 10 when the switching element 22 is in a conductive state, and indicates the portion detected by the Rogowski coil 12. The waveform IL here indicates the waveform of the second detection signal generated by the integration circuit 40-2.

[0059] The adder 131 of the current detection device 10 adds the first detection signal of the integrating circuit 40-1 and the second detection signal of the integrating circuit 40-2, and outputs a detection current waveform (current value IFB) as shown in FIG. 5(a). In the example shown in FIG. 5(a), since the detected current (detected current value IFB) is larger than the predetermined current value Ith, the power supply control unit 331 performs control in the continuous operation mode.

[0060] 5(b) shows an example of a detected current of the current detection device 10 in the intermittent operation mode. In the intermittent operation mode, the power supply control unit 331 stops the control for alternately turning on the switching element 21 and the switching element 22 for a stop period TR1, and operates the switching element 21 and the switching element 22 intermittently. In the example shown in FIG. 5(b), since the detected current (detected current value IFB) is equal to or less than the predetermined current value Ith, the power supply control unit 331 performs control in the intermittent operation mode.

[0061] Next, the operation of the current detection device 10 will be described with reference to FIGS. Fig. 6 is a flowchart showing an example of the operation of the current detection device 10 according to the present embodiment. Fig. 7 is a timing chart showing an example of the operation of the current detection device 10 according to the present embodiment. Here, a process for generating a reset signal for the integrating circuit 40 in the current detection device 10 will be described.

[0062] 6, the reset generation unit 50 of the current detection device 10 first determines whether or not it is the stop period TR1 of the intermittent operation mode (step S201). If it is the stop period TR1 of the intermittent operation mode (step S201: YES), the reset control unit 332 of the reset generation unit 50 advances the process to step S202. If it is not the stop period TR1 of the intermittent operation mode (step S201: NO), the reset control unit 332 advances the process to step S203.

[0063] In step S202, the reset control unit 332 fixes the integrating circuit 40 in a reset state. That is, the reset control unit 332 sets the control signal S3 to a High state, sets the reset switch 55 to a conductive state, and fixes the reset signal RST_H to a Low state. The reset control unit 332 also sets the control signal S4 to a High state, sets the reset switch 56 to a conductive state, and fixes the reset signal RST_L to a Low state. After the process of step S202, the reset control unit 332 returns the process to step S201.

[0064] In step S203, the reset generation unit 50 generates a reset signal for the integrating circuit based on the switching control signal. That is, the inverter circuit 53 logically inverts the control signal S2 output by the reset control unit 332 to generate the reset signal RST_H. In addition, the inverter circuit 51 logically inverts the control signal S1 output by the reset control unit 332 to generate the reset signal RST_L. After the process of step S203, the reset control unit 332 returns the process to step S201.

[0065] 7, waveforms W1 to W10 indicate, from top to bottom, the waveforms of the high-side current value of the switching unit 20, the high-side control signal S1, the reset signal RST_H, the output signal of the high-side integration circuit 40-1, the control signal S3, the low-side current value of the switching unit 20, the low-side control signal S2, the reset signal RST_L, the output signal of the low-side integration circuit 40-2, and the control signal S4. The horizontal axis indicates time. In addition, the example shown in FIG. 7 illustrates the operation of the current detection device 10 in the intermittent operation mode.

[0066] This shows a state in which the switching unit 20 is operating before time T1. In this case, the reset signal RST_H of the integrating circuit 40-1 is generated by inverting the low-side control signal S2 that controls the low-side switching element 22 by the inverter circuit 53 (see waveforms W2 and W7). When the low-side control signal S2 is in a high state, the integrating circuit 40-2 outputs an output signal as shown in waveform W9 (see waveforms W7 and W9) to bring the low-side switching element 22 into a conductive state.

[0067] Moreover, the reset signal RST_L of the integrating circuit 40-2 is generated by inverting the High-side control signal S1 that controls the High-side switching element 21 by the inverter circuit 51 (see waveforms W2 and W8). Moreover, when the High-side control signal S1 is in a High state, in order to bring the High-side switching element 21 into a conductive state, the integrating circuit 40-1 outputs an output signal as shown in waveform W4 (see waveforms W3 and W4). Also in this case, the reset control unit 332 sets the control signals S3 and S4 to a low state, and sets the reset switches 55 and 56 to a non-conductive state (see waveforms W5 and W10).

[0068] In addition, during the stop period TR1 after time T1, the power supply control unit 331 sets the High side control signal S1 and the Low side control signal S2 to a Low state (see waveforms W2 and W7). In this case, the inverter circuit 51 and the inverter circuit 53 logically invert the control signal S1 and the control signal S2 to a High state as shown in waveforms W80 and W30. However, in this case, the reset control unit 332 sets the control signal S3 and the control signal S4 to a High state and sets the reset switch 55 and the reset switch 56 to a conductive state (see waveforms W5 and W10). As a result, the reset signal RST_H and the reset signal RST_L are fixed to a Low state, and the integrating circuit 40-1 and the integrating circuit 40-2 are reset. Therefore, the output signals of the integrating circuit 40-1 and the integrating circuit 40-2 are maintained at the detected current value "0" (see waveforms W4 and W9).

[0069] 7, for comparison, waveforms W40 and W90 show the output signals of the integrating circuits 40-1 and 40-2 in the case of the conventional technology without the reset generating unit 50 of the present embodiment. In this case, during the stop period TR1 of the intermittent operation mode, the reset signals RST_L and RST_H are in the High state as shown in waveforms W30 and W80, so that the integrating circuits 40-1 and 40-2 are not in the reset state. Therefore, the output signals of the integrating circuits 40-1 and 40-2 gradually rise as shown in waveforms W40 and W90, and an offset voltage occurs, so that the current flowing through the switching unit 20 cannot be accurately detected in the next current detection.

[0070] In contrast, in the current detection device 10 of this embodiment, the reset generation unit 50 fixes the integrating circuits 40-1 and 40-2 to a reset state during the stop period TR1, so that the current flowing through the switching unit 20 can be accurately detected in the next current detection.

[0071] As described above, the current detection device 10 according to the present embodiment has a switching element 21 (first switching element) and a switching element 22 (second switching element) connected in series, and detects a current flowing through a switching unit 20 that operates a power supply device 1, and includes a Rogowski coil 11 (first Rogowski coil), a Rogowski coil 12 (second Rogowski coil), an integrating circuit 40-1 (first integrating circuit), an integrating circuit 40-2 (second integrating circuit), a detection processing unit 13, and a reset generating unit 50. The Rogowski coil 11 detects a current flowing through the switching element 21. The Rogowski coil 12 detects a current flowing through the switching element 22. The integrating circuit 40-1 has a reset function, and integrates the output of the Rogowski coil 11 to output a first detection signal. The integrating circuit 40-2 has a reset function, and integrates the output of the Rogowski coil 12 to output a second detection signal. The detection processing unit 13 detects the current flowing through the switching unit 20 based on the first detection signal and the second detection signal. When the switching unit 20 is in an intermittent operation mode in which the switching unit 20 operates intermittently, the reset generation unit 50 fixes the integrating circuits 40-1 and 40-2 to a reset state during a stop period in which both the switching elements 21 and 22 are in a non-conductive state.

[0072] As a result, in the current detection device 10 according to the present embodiment, the integrating circuit 40-1 having a reset function integrates the output of the Rogowski coil 11 to output a first detection signal, and the integrating circuit 40-2 having a reset function integrates the output of the Rogowski coil 12 to output a second detection signal. The detection processing unit 13 detects the current flowing through the switching unit 20 based on the first detection signal and the second detection signal. When the reset generating unit 50 is in an intermittent operation mode in which the switching unit 20 is operated intermittently, the integrating circuits 40-1 and 40-2 are fixed in a reset state during a stop period TR1 in which both the switching element 21 and the switching element 22 are made non-conductive. Since the integrating circuits 40-1 and 40-2 are fixed in a reset state during a stop period in the intermittent operation mode, the current detection device 10 can reduce the influence of the offset voltage of the integrating circuits 40-1 and 40-2 (see waveforms W4 and W9 in FIG. 7). Therefore, the current detection device 10 according to the present embodiment can detect the current with high accuracy even when the switching unit 20 is operated intermittently.

[0073] In this embodiment, in the continuous operation mode, the reset generator 50 generates a reset signal RST_H (first reset signal) that resets the integrator circuit 40-1 before the switching element 21 becomes conductive and sets the period during which the switching element 21 is in the conductive state to a reset release state, and a reset signal RST_L (second reset signal) that resets the integrator circuit 40-2 before the switching element 22 becomes conductive and sets the period during which the switching element 22 is in the conductive state to a reset release state. Here, the continuous operation mode is an operation mode in which the switching elements 21 and 22 are alternately set to the conductive state in a continuous and periodic manner.

[0074] As a result, the current detection device 10 according to the present embodiment can appropriately reset the integrating circuit 40-1 and the integrating circuit 40-2 in the continuous operation mode, and can detect the current with high accuracy.

[0075] In addition, in this embodiment, the reset generation unit 50 generates the reset signal RST_H and the reset signal RST_L based on a control signal S1 (first control signal) that puts the switching element 21 into a conductive state, and a control signal S2 (second control signal) that puts the switching element 22 into a conductive state. As a result, the current detection device 10 according to the present embodiment can appropriately generate the reset signals RST_H and RST_L by a simple method using the control signals S1 and S2.

[0076] In addition, in this embodiment, the reset generation unit 50 is equipped with a reset switch 55 (first reset switch) that sets the reset signal RST_H to a reset state (e.g., a Low state) and a reset switch 56 (second reset switch) that sets the signal RST_L to a reset state (e.g., a Low state) during the stop period TR1 of the intermittent operation mode. As a result, the current detection device 10 according to the present embodiment can appropriately fix the reset signals RST_H and RST_L to the reset state with a simple configuration using the reset switches 55 and 56.

[0077] Moreover, the power supply device 1 according to the present embodiment includes the above-described current detection device 10, a switching unit 20, and a power supply control unit 331 that controls the switching unit 20 based on the current value detected by the current detection device 10. As a result, the power supply device 1 according to this embodiment has the same effect as the above-mentioned current detection device 10, and can detect the current with high accuracy even when the switching unit 20 is operated intermittently. Furthermore, the power supply device 1 according to this embodiment can detect the current with high accuracy when the switching unit 20 is operated intermittently, thereby improving the output accuracy of the output voltage.

[0078] Furthermore, in this embodiment, the power supply control unit 331 switches to the intermittent operation mode when the current value is equal to or less than a predetermined current value. As a result, the power supply device 1 according to this embodiment can improve the output accuracy of the output voltage by switching to the intermittent operation mode when the load is low.

[0079] The current detection method according to the present embodiment is a current detection method for detecting a current flowing through a switching unit 20 that has a switching element 21 and a switching element 22 connected in series and operates a power supply device 1, and includes a first integration step, a second integration step, a detection processing step, and a reset generation step. In the first integration step, an integrating circuit 40-1 having a reset function integrates the output of a Rogowski coil 11 that detects a current flowing through the switching element 21 to output a first detection signal. In the second integration step, an integrating circuit 40-2 having a reset function integrates the output of a Rogowski coil 12 that detects a current flowing through the switching element 22 to output a second detection signal. In the detection processing step, a detection processing unit 13 detects a current flowing through the switching unit 20 based on the first detection signal and the second detection signal. In the reset generation step, when the switching unit 20 is in an intermittent operation mode in which the switching unit 20 is operated intermittently, a reset generation unit 50 fixes the integrating circuits 40-1 and 40-2 to a reset state during a stop period in which both the switching elements 21 and 22 are in a non-conductive state. As a result, the current detection method according to the present embodiment has the same effects as the current detection device 10 described above, and can detect the current with high accuracy even when the switching unit 20 is operated intermittently.

[0080] The present invention is not limited to the above-described embodiment, and can be modified without departing from the spirit of the present invention. For example, in the above embodiment, the power supply device 1 is described as a power supply device using a step-down chopper circuit, but the present invention is not limited to this, and may be a power supply device of another type as long as it has a switching unit having a first switching element and a second switching element connected in series and performs intermittent operation.

[0081] In addition, in the above embodiment, an example has been described in which the power supply control unit 331 uses the detected current value detected by the current detection device 10 as is, but this is not limited to this, and the power supply control unit 331 may use, for example, an average value or a moving average value of the detected current value over a specified period.

[0082] In the above embodiment, the reset state is set when the reset signal of the integration circuit 40 is in a low state, but this is not limited to the above, and the reset state may be set when the reset signal is in a high state, for example. The configuration of the circuit that generates the reset signal of the reset generation unit 50 is not limited to the above embodiment, and the reset signal may be generated by other methods (circuits).

[0083] Each of the components of the power supply device 1 described above has an internal computer system. A program for implementing the functions of each of the components of the power supply device 1 described above may be recorded on a computer-readable recording medium, and the program recorded on the recording medium may be read into a computer system and executed to perform processing in each of the components of the power supply device 1 described above. Here, "reading a program recorded on a recording medium into a computer system and executing it" includes installing the program into a computer system. The "computer system" referred to here includes hardware such as an OS and peripheral devices.

[0084] Furthermore, a "computer system" may include multiple computer devices connected via a network including the Internet, WAN, LAN, dedicated lines, and other communication lines. Furthermore, a "computer-readable recording medium" refers to portable media such as flexible disks, optical magnetic disks, ROMs, and CD-ROMs, and storage devices such as hard disks built into a computer system. In this way, the recording medium storing the program may be a non-transitory recording medium such as a CD-ROM.

[0085] The recording medium also includes a recording medium installed inside or outside and accessible from a distribution server to distribute the program. The program may be divided into a plurality of parts, downloaded at different times, and then combined with each component of the power supply device 1, or each divided program may be distributed by a different distribution server. Furthermore, the "computer-readable recording medium" includes a recording medium that holds a program for a certain period of time, such as a volatile memory (RAM) inside a computer system that becomes a server or a client when a program is transmitted via a network. The program may be a recording medium for implementing part of the above-mentioned functions. Furthermore, the program may be a so-called difference file (difference program) that can realize the above-mentioned functions in combination with a program already recorded in the computer system.

[0086] In addition, some or all of the above-mentioned functions may be realized as an integrated circuit such as LSI (Large Scale Integration). Each of the above-mentioned functions may be individually processed, or some or all of the functions may be integrated into a processor. The integrated circuit method is not limited to LSI, and may be realized by a dedicated circuit or a general-purpose processor. In addition, if an integrated circuit technology that can replace LSI appears due to advances in semiconductor technology, an integrated circuit based on that technology may be used. [Explanation of symbols]

[0087] 1 Power supply 10 Current detection device 11, 12 Rogowski coil 13 Detection processing section 14, 16, 43 Capacitor 17, 18, 23, 24, 41, 52, 54 Resistance 20 Switching section 21, 22 Switching element 30 Control IC 31, 32 Buffer circuit 33 Control Unit 40, 40-1, 40-2 Integrator circuit 42 Operational Amplifiers 44 Switch 50 Reset Generation Unit 51, 53 Inverter circuit 55, 56 Reset switch 131 Adder 331 Power supply control unit 332 Reset control section

Claims

1. A current detection device having a first switching element and a second switching element connected in series, the current detection device detecting a current flowing through a switching unit that operates a power supply device, a first Rogowski coil for detecting a current flowing through the first switching element; a second Rogowski coil for detecting a current flowing through the second switching element; a first integration circuit having a reset function and integrating an output of the first Rogowski coil to output a first detection signal; a second integration circuit having a reset function and integrating an output of the second Rogowski coil to output a second detection signal; a detection processing unit that detects a current flowing in the switching unit based on the first detection signal and the second detection signal; a reset generating unit that fixes the first integration circuit and the second integration circuit to a reset state during an entire stop period in which both the first switching element and the second switching element are made non-conductive when the switching unit is in an intermittent operation mode in which the switching unit is operated intermittently; A current detection device comprising:

2. The reset generation unit is a first reset switch that resets a first reset signal that resets the first integration circuit during the entire stop period of the intermittent operation mode; a second reset switch that resets a second reset signal that resets the second integration circuit during the entire stop period of the intermittent operation mode; a reset control unit that controls the first reset switch and the second reset switch to fix the first reset signal and the second reset signal to the reset state during the entire stop period of the intermittent operation mode; The current detection device according to claim 1 .

3. The reset generation unit, in a continuous operation mode in which the first switching element and the second switching element are alternately brought into a conductive state in a continuous and periodic manner, generates the first reset signal that resets the first integration circuit before the first switching element becomes conductive and brings a reset release state into a period in which the first switching element is in a conductive state, and the second reset signal that resets the second integration circuit before the second switching element becomes conductive and brings a reset release state into a period in which the second switching element is in a conductive state.

3. The current detection device according to claim 2.

4. The reset generating unit generates the first reset signal and the second reset signal based on a first control signal that sets the first switching element in a conductive state and a second control signal that sets the second switching element in a conductive state.

4. The current detection device according to claim 3.

5. A current detection device according to any one of claims 1 to 4, The switching unit; a power supply control unit that controls the switching unit based on the current value detected by the current detection device; A power supply device comprising:

6. The power supply control unit is When the current value is equal to or lower than a predetermined current value, the intermittent operation mode is set.

6. The power supply device according to claim 5.

7. A current detection method for detecting a current flowing through a switching unit that operates a power supply device, the switching unit having a first switching element and a second switching element connected in series, comprising: a first integration step in which a first integration circuit having a reset function integrates an output of a first Rogowski coil that detects a current flowing through the first switching element, and outputs a first detection signal; a second integration step in which a second integration circuit having a reset function integrates an output of a second Rogowski coil that detects a current flowing through the second switching element, and outputs a second detection signal; a detection processing step in which a detection processing unit detects a current flowing in the switching unit based on the first detection signal and the second detection signal; a reset generating step of fixing the first integration circuit and the second integration circuit to a reset state during an entire stop period in which both the first switching element and the second switching element are in a non-conductive state when the reset generating unit is in an intermittent operation mode in which the switching unit is operated intermittently; A current detection method comprising:

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