Current detection circuit, overcurrent protection device, intelligent power module and household appliances

Abstract

The present invention discloses a current detection circuit, an overcurrent protection device, an intelligent power module and a household appliance. The circuit includes: a detection unit generates a detection voltage according to a target current; a mirror unit outputs a mirror voltage based on the detection voltage when the target current is in a first direction; a first comparison unit outputs a first comparison signal when the mirror voltage rises to a preset voltage threshold; a follower unit outputs a follower voltage based on the detection voltage when the target current is in a second direction; a second comparison unit outputs a second comparison signal when the follower voltage drops to a preset voltage threshold; and a sampling unit is configured to sample the first comparison signal and the second comparison signal to determine the overcurrent state of the target current. The circuit determines the current overcurrent state in different directions by sampling the first comparison signal and the second comparison signal to meet the overcurrent detection requirements for positive and negative currents, thereby ensuring the scope of application of the circuit.

Description

Technical Field

[0001] The present invention relates to the technical field of household electrical appliances, and in particular to a current detection circuit, an overcurrent protection device, an intelligent power module and a household electrical appliance. Background Art

[0002] Current detection is crucial to the operational stability of electrical equipment. In related technologies, current detection circuits are selected and applied based on the direction of current, and have a small scope of application, making it difficult to simultaneously meet the overcurrent detection requirements in both positive and negative directions. Summary of the invention

[0003] The present invention aims to solve at least one of the technical problems in the related art to a certain extent. To this end, the first object of the present invention is to provide a current detection circuit, which samples a first comparison signal and a second comparison signal to determine the overcurrent state of the target current in the first direction and the second direction, thereby meeting the overcurrent detection requirements for positive and negative currents and ensuring the scope of application of the circuit.

[0004] The second objective of the present invention is to provide an overcurrent protection device.

[0005] The third objective of the present invention is to provide an intelligent power module.

[0006] A fourth objective of the present invention is to provide a household appliance.

[0007] To achieve the above-mentioned purpose, an embodiment of the first aspect of the present invention proposes a current detection circuit, comprising: a detection unit, suitable for detecting a target current to generate a detection voltage; a mirror unit, suitable for mirroring the detection voltage and outputting a mirror voltage when the direction of the target current is a first direction; a first comparison unit, suitable for comparing the mirror voltage and outputting a first comparison signal when the mirror voltage rises to a preset voltage threshold; a following unit, suitable for following the detection voltage and outputting a follow voltage when the direction of the target current is a second direction, wherein the second direction is opposite to the first direction; a second comparison unit, suitable for comparing the follow voltage and outputting a second comparison signal when the follow voltage drops to a preset voltage threshold; and a sampling unit, configured to sample the first comparison signal and the second comparison signal to determine an overcurrent state of the target current.

[0008] According to the current detection circuit of the embodiment of the present invention, the target current is detected by the detection unit to generate a detection voltage, the mirror unit mirrors the detection voltage when the direction of the target current is the first direction, and outputs the mirror voltage, the first comparison unit compares the mirror voltage, and outputs a first comparison signal when the mirror voltage rises to a preset voltage threshold, the follower unit follows the detection voltage when the direction of the target current is the second direction, and outputs a follower voltage, wherein the second direction is opposite to the first direction, the second comparison unit compares the follower voltage, and outputs a second comparison signal when the follower voltage drops to a preset voltage threshold, and the sampling unit samples the first comparison signal and the second comparison signal to determine the overcurrent state of the target current. Thus, the circuit determines the overcurrent state of the target current in the first direction and the second direction by sampling the first comparison signal and the second comparison signal, thereby meeting the overcurrent detection requirements for positive and negative currents and ensuring the scope of application of the circuit.

[0009] In addition, the current detection circuit according to the above embodiment of the present invention may also have the following additional technical features:

[0010] According to an embodiment of the present invention, the detection unit includes at least one current-sensing resistor, one end of the current-sensing resistor is grounded, and the other end of the current-sensing resistor serves as an output end of the detection unit.

[0011] According to one embodiment of the present invention, the mirror unit includes a first diode, a second diode and a first resistor, the anode of the first diode is connected to the anode of the second diode and then connected to one end of the first resistor, the other end of the first resistor is connected to a reference power supply, the cathode of the first diode is connected to the output end of the detection unit, and the cathode of the second diode is suitable for connecting to the first comparison unit.

[0012] According to one embodiment of the present invention, when there are three current-sensing resistors, there are three mirror units, wherein the cathode of the first diode in each mirror unit is respectively connected to the other end of the corresponding current-sensing resistor among the three current-sensing resistors; the cathodes of the second diodes in the three mirror units are connected together as the output end of the mirror unit.

[0013] According to an embodiment of the present invention, the mirror unit further includes: a second resistor, one end of the second resistor is connected to the cathode of the second diode, and the other end of the second resistor is grounded.

[0014] According to one embodiment of the present invention, the current detection circuit further includes: a third resistor, one end of the third resistor is connected to the sampling end of the sampling unit, and the other end of the third resistor is grounded; and a first capacitor, which is connected in parallel with the third resistor.

[0015] According to one embodiment of the present invention, the follower unit includes: a third diode, the cathode of the third diode is suitable for connecting to the output end of the detection unit; a fourth resistor, one end of the fourth resistor is connected to the anode of the third diode; a fifth resistor, one end of the fifth resistor is connected to the other end of the fourth resistor and has a first node, and the other end of the fifth resistor is connected to a reference power supply; a fourth diode, the anode of the fourth diode is connected to the first node; a sixth resistor, one end of the sixth resistor is connected to the cathode of the fourth diode and has a second node, the other end of the sixth resistor is grounded, and the second node serves as the output end of the follower unit.

[0016] According to one embodiment of the present invention, the first comparison unit includes: a first comparator, wherein the positive input terminal of the first comparator is connected to the output terminal of the mirror unit, and the negative input terminal of the first comparator is connected to the providing terminal of the preset voltage threshold; a seventh resistor, wherein one end of the seventh resistor is connected to the output terminal of the first comparator, and the other end of the seventh resistor is connected to a reference power supply; and a fifth diode, wherein the anode of the fifth diode is connected to the output terminal of the first comparator, and the cathode of the fifth diode serves as the output terminal of the first comparison unit.

[0017] According to one embodiment of the present invention, the second comparison unit includes: a second comparator, the negative input terminal of the second comparator is connected to the output terminal of the follower unit, and the positive input terminal of the second comparator is connected to the providing terminal of the preset voltage threshold; an eighth resistor, one end of the eighth resistor is connected to the output terminal of the second comparator, and the other end of the eighth resistor is connected to the reference power supply; a sixth diode, the anode of the sixth diode is connected to the output terminal of the second comparator, and the cathode of the sixth diode serves as the output terminal of the second comparison unit.

[0018] According to an embodiment of the present invention, the sampling unit includes a controller, and a sampling terminal of the controller is connected to an output terminal of the first comparing unit and an output terminal of the second comparing unit respectively.

[0019] According to an embodiment of the present invention, the first comparison unit and the second comparison unit may be integrated into the MCU of the controller.

[0020] To achieve the above-mentioned purpose, the second aspect of the embodiment of the present invention proposes an overcurrent protection device, including: the above-mentioned current detection circuit, suitable for detecting the target current to determine the overcurrent state of the target current; a controller, configured to generate an overcurrent protection signal according to the overcurrent state.

[0021] According to the overcurrent protection device of the embodiment of the present invention, the target current is detected by the current detection circuit to determine the overcurrent state of the target current, and the controller generates an overcurrent protection signal according to the overcurrent state. Therefore, based on the current detection, the device can complete the current overcurrent state detection in different directions, ensuring the positive and negative overcurrent protection effects.

[0022] To achieve the above-mentioned purpose, the third aspect of the embodiment of the present invention proposes an intelligent power module, including: a three-phase inverter bridge, the three-phase inverter bridge includes three-phase bridge arms, each phase arm in the three-phase bridge arm includes an upper bridge switch tube and a lower bridge switch tube; the above-mentioned current detection circuit, the current detection circuit is suitable for detecting the positive and negative current of each phase of the three-phase inverter bridge.

[0023] According to the intelligent power module of the embodiment of the present invention, the three-phase inverter bridge includes a three-phase bridge arm, each phase of the three-phase bridge arm includes an upper bridge switch tube and a lower bridge switch tube, and the above-mentioned current detection circuit detects the positive and negative current of each phase of the three-phase inverter bridge. Therefore, the module realizes overcurrent state detection under different current directions based on the above-mentioned current detection circuit, so that it meets the positive and negative overcurrent detection requirements of the module and effectively protects the intelligent power module.

[0024] In addition, the intelligent power module according to the above embodiment of the present invention may also have the following additional technical features:

[0025] According to an embodiment of the present invention, when the current detection circuit includes a current sensing resistor, one end of the current sensing resistor is grounded, and the other end of the current sensing resistor is respectively connected to the lower bridge switch tube in each phase bridge arm.

[0026] According to an embodiment of the present invention, when the current detection circuit includes three current detection resistors, one end of each current detection resistor is grounded, and the other end of each current detection resistor is connected to a corresponding lower bridge switch tube in each phase bridge arm.

[0027] To achieve the above-mentioned purpose, a fourth aspect of the present invention provides a household appliance, comprising: a motor; and the above-mentioned intelligent power module, wherein the intelligent power module is suitable for driving the motor.

[0028] According to the household appliance device of the embodiment of the present invention, the motor is driven by the above-mentioned intelligent power module. Based on the above-mentioned intelligent power module, the household appliance device can realize the detection of the current overcurrent state in different directions, so that it meets the overcurrent detection requirements of the motor operation, improves the overcurrent protection effect of the motor, and ensures the operation stability of the household appliance device.

[0029] Additional aspects and advantages of the present invention will be given in part in the following description and in part will be obvious from the following description, or will be learned through practice of the present invention. BRIEF DESCRIPTION OF THE DRAWINGS

[0030] Figure 1 is a connection diagram of a current detection circuit according to an embodiment of the present invention;

[0031] Figure 2 A circuit diagram of a mirror unit and a first comparison unit according to a specific embodiment of the present invention Figure 1 ;

[0032] Figure 3 A circuit diagram of a mirror unit and a first comparison unit according to a specific embodiment of the present invention Figure 2 ;

[0033] Figure 4 A circuit connection diagram of a current sensing resistor according to a specific embodiment of the present invention;

[0034] Figure 5 A circuit diagram of a follower unit and a second comparison unit according to a specific embodiment of the present invention Figure 1 ;

[0035] Figure 6 A circuit diagram of a follower unit and a second comparison unit according to a specific embodiment of the present invention Figure 2 ;

[0036] Figure 7 is a circuit diagram of a current detection circuit according to a specific embodiment of the present invention;

[0037] Figure 8 for Figure 7 A current schematic diagram when the direction of the target current is a first direction;

[0038] Fig. 9 for Figure 7 A current schematic diagram when the direction of the target current is the second direction;

[0039] Fig.10 is a circuit diagram of a current detection circuit according to another specific embodiment of the present invention;

[0040] Fig.11 is a block diagram of an overcurrent protection device according to an embodiment of the present invention;

[0041] Fig.12 is a circuit diagram of an overcurrent protection device according to a specific embodiment of the present invention;

[0042] Fig.13 is a block diagram of an intelligent power module according to an embodiment of the present invention;

[0043] Fig.14 FIG. 4 is a block diagram of a household appliance according to an embodiment of the present invention. DETAILED DESCRIPTION

[0044] Embodiments of the present invention are described in detail below, examples of which are shown in the accompanying drawings, wherein the same or similar reference numerals throughout represent the same or similar elements or elements having the same or similar functions. The embodiments described below with reference to the accompanying drawings are exemplary and are intended to be used to explain the present invention, and should not be construed as limiting the present invention.

[0045] The current detection circuit, overcurrent protection device, intelligent power module and household appliance proposed in the embodiments of the present invention are described below with reference to the accompanying drawings.

[0046] Figure 1 FIG. 4 is a connection diagram of a current detection circuit according to an embodiment of the present invention.

[0047] like Figure 1 As shown, the current detection circuit of the embodiment of the present invention may include: a detection unit 10 , a mirror unit 20 , a first comparison unit 30 , a follower unit 40 , a second comparison unit 50 and a sampling unit 60 .

[0048] Among them, the detection unit 10 is suitable for detecting the target current to generate a detection voltage. The mirror unit 20 is suitable for mirroring the detection voltage and outputting the mirror voltage when the direction of the target current is a first direction. The first comparison unit 30 is suitable for comparing the mirror voltage to output a first comparison signal when the mirror voltage rises to a preset voltage threshold. The following unit 40 is suitable for following the detection voltage and outputting a follow-up voltage when the direction of the target current is a second direction, wherein the second direction is opposite to the first direction. The second comparison unit 50 is suitable for comparing the follow-up voltage to output a second comparison signal when the follow-up voltage drops to a preset voltage threshold. The sampling unit 60 is configured to sample the first comparison signal and the second comparison signal to determine the overcurrent state of the target current.

[0049] Specifically, the target current is detected by the detection unit 10, and a corresponding detection voltage is output according to the target current. The detection voltage corresponds to the polarity and magnitude of the target current. For example, when the direction of the target current is positive, the target current is a positive current, and the corresponding detection voltage is a positive voltage. As the target current increases in the positive direction, the detection voltage gradually increases in the positive direction; when the direction of the target current is negative, the target current is a negative current, and the corresponding detection voltage is a negative voltage. As the target current increases in the negative direction, the detection voltage gradually increases in the negative direction, that is, the negative current gradually increases, and the negative voltage also increases accordingly. It should be noted that the increase in the positive and negative directions refers to the increase in the absolute value.

[0050] The following takes the first direction and the second direction as negative directions as an example.

[0051] When the direction of the target current is forward, the target current is a positive current, and the detection voltage is a positive voltage. The mirror unit 20 outputs a mirror voltage equal to the detection voltage according to the received detection voltage, and sends it to the first comparison unit 30. The first comparison unit 30 compares the received mirror voltage with the preset voltage threshold. When it is determined that the mirror voltage rises to the preset voltage threshold, it outputs a first comparison signal, otherwise it does not output. In addition, when the target current is in the first direction, the path between the detection unit 10, the following unit 40, the second comparison unit 50 and the sampling unit 60 can be controlled to be disconnected to ensure that the second comparison unit 50 does not output. In addition, the circuit can also be set so that the follower voltage output by the following unit 40 when the target current is a positive current is always greater than the preset voltage threshold to ensure that the second comparison unit 50 does not output the second comparison signal. Therefore, when the direction of the target current is the first direction, the sampling unit 60 only receives the first comparison signal, and judges the overcurrent state of the target current according to the received first comparison signal, that is, when the sampling unit 60 determines that the first comparison signal is received, it is considered that the target current has a forward overcurrent, otherwise it is considered that the target current has not a forward overcurrent.

[0052] When the direction of the target current is negative, the target current is a negative current and the detection voltage is a negative voltage. The following unit 40 follows the detection voltage and outputs a corresponding following voltage. Specifically, when the target current increases in a negative direction, the detection voltage increases in a negative direction and the following voltage decreases; when the target current decreases in a negative direction, the detection voltage decreases in a negative direction and the following voltage increases. The following voltage is compared with a preset voltage threshold by the second comparison unit 50, and when the following voltage drops to the preset voltage threshold, a second comparison signal is output, otherwise no output. In addition, when the target current is in the second direction, the path between the detection unit 10, the mirror unit 20, the first comparison unit 30 and the sampling unit 60 can be controlled to be disconnected to ensure that the first comparison unit 30 does not output. In addition, the mirror unit 20 can also be configured to not output when the target current is a positive current through circuit settings, which is not limited here. Therefore, when the direction of the target current is the second direction, the sampling unit 60 only receives the second comparison signal, and determines the overcurrent state of the target current based on the received second comparison signal, that is, when the sampling unit 60 determines that the second comparison signal is received, it is considered that a negative overcurrent has occurred in the target current, otherwise it is considered that no negative overcurrent has occurred in the target current.

[0053] Therefore, this embodiment can realize overcurrent detection of current in positive and negative directions, ensuring the applicable scope of overcurrent detection of the circuit.

[0054] In addition, the first comparison signal and the second comparison signal may be high or low level signals or voltage signals, which may be set according to actual conditions and are not limited here.

[0055] By further example, the sampling unit 60 can be provided with two connection ports, which are respectively connected to the first comparison unit 30 and the second comparison unit 50 through the two ports, and determine whether a positive overcurrent or a negative overcurrent occurs based on different control logics. For example, taking the first comparison signal and the second comparison signal as voltage signals, the sampling unit 60 is connected to the first comparison unit 30 through the A port and to the second comparison unit 50 through the B port. It can be determined whether a positive overcurrent occurs by using the first comparison signal received at the A port, and whether a negative overcurrent occurs by using the second comparison signal received at the B port. When the first comparison signal and the second comparison signal are level signals, the overcurrent state can also be determined based on the level change of the port.

[0056] In addition, since the comparison signal output by the first comparison unit 30 and the second comparison unit 50 can be a set voltage value or level, the first comparison signal and the second comparison signal can also be set to the same signal. At this time, the sampling unit 60 can be connected to the first comparison unit 30 and the second comparison unit 50 at the same time through a connection port to determine the overcurrent state with the same overcurrent judgment condition.

[0057] Combination Figure 2 As shown, in one embodiment of the present invention, the detection unit 10 includes at least one current-sensing resistor Rs, one end of the current-sensing resistor Rs is grounded, and the other end of the current-sensing resistor Rs serves as an output end of the detection unit 10 .

[0058] That is to say, the current sensing resistor Rs is connected in series in the target circuit, and the detection voltage is the voltage at the upper end (the other end) of the current sensing resistor Rs, satisfying the formula Vs=Rs*Is, where Vs is the detection voltage, Rs is the current sensing resistor, and Is is the target current. The number of current sensing resistors Rs can be set according to actual needs and is not limited here.

[0059] In one embodiment of the present invention, the mirror unit 20 includes a first diode D1, a second diode D2 and a first resistor R1, an anode of the first diode D1 is connected to an anode of the second diode D2 and then connected to one end of the first resistor R1, the other end of the first resistor R1 is connected to a reference power supply Vdd, a cathode of the first diode D1 is connected to an output end of the detection unit 10, and a cathode of the second diode D2 is suitable for connecting to the first comparison unit 30.

[0060] In one embodiment of the present invention, the mirror unit 20 further includes: a second resistor R2, one end of the second resistor R2 is connected to the cathode of the second diode D2, and the other end of the second resistor R2 is grounded.

[0061] Specifically, when the direction of the target current is the first direction, that is, when the target current is a positive current, the first diode D1 is turned on, and the anode voltage of the first diode D1 is Vs+Vf1, where Vs is the detection voltage, and Vf1 is the voltage drop on the first diode D1, then the voltage value output through the cathode of the second diode D2 is Vs+Vf1-Vf2, where Vf1 is the voltage drop of the first diode D1, and Vf2 is the voltage drop of the second diode D2, Vf1=Vf2, thus, the mirror voltage output through the cathode of the second diode D2 is equal to the detection voltage Vs, that is, the voltage value of the mirror voltage is equal to the detection voltage, thereby avoiding the influence of the voltage drop of the diode on the sampling accuracy and improving the detection accuracy. The first comparison unit 30 compares the received mirror voltage with the preset voltage threshold, and outputs a first comparison signal when the mirror voltage rises to the preset voltage threshold.

[0062] When the direction of the target current is the second direction, that is, when the target current is a negative current, the detection voltage is a negative voltage, the first diode D1 is turned on, and the second diode D2 is not turned on. At this time, the mirror unit 20 does not output the mirror voltage to the first comparison unit 30, thereby ensuring that the first comparison unit 30 does not output when the direction of the target current is the second direction.

[0063] Combination Figure 3 As shown, in one embodiment of the present invention, when there are three current-sense resistors Rs, there are three mirror units 20, wherein the cathode of the first diode D1 in each mirror unit 20 is respectively connected to the other end of the corresponding current-sense resistor Rs in the three current-sense resistors Rs; the cathodes of the second diodes D2 in the three mirror units 20 are connected together as the output end of the mirror unit 20.

[0064] Specifically, the three current-sensing resistors are represented by Rsu, Rsv, and Rsw, respectively, and the corresponding detection voltages are the upper end voltages of the corresponding current-sensing resistors, respectively represented by Vsu, Vsv, and Vsw. The cathodes of the first diodes D1 in the three mirror units 20 are respectively connected to the other ends of the current-sensing resistors Rsu, Rsv, and Rsw, for obtaining the detection voltage on the corresponding current-sensing resistors, and outputting the corresponding mirror voltage, i.e., the received detection voltage, through the cathode of the corresponding second diode D2. The cathodes of the second diodes D2 in the three mirror units 20 are connected together to form a node, the voltage at the node being the maximum voltage value among the cathode voltages of the three second diodes D2, i.e., the maximum detection voltage among the detection voltages output by the three current-sensing resistors.

[0065] This embodiment outputs mirror voltages corresponding to three detection voltages respectively through three mirror units 20, and outputs the maximum mirror voltage among the three mirror voltages, namely the maximum detection voltage, through a node. The first comparison unit 30 outputs a first comparison signal based on the maximum detection voltage. Thus, the sampling unit 60 can determine the overcurrent state of the maximum target current among the three target currents according to the detection voltage to determine whether current overcurrent occurs in the first direction.

[0066] For further example, assume that three detection units 10 are used for motor current detection, and the current detection resistor Rs is connected in series in the motor drive circuit. Figure 4 As shown, the motor drive circuit includes a three-phase inverter bridge 1 composed of six switch tubes (respectively represented by U+, U-, V+, V-, W+, and W-). In the three-phase inverter bridge 1, the switch tubes are teamed in pairs to form three parallel bridge arms, and each bridge arm is formed with corresponding output nodes respectively connected to the lead-out ends of the three-phase windings of the motor 2. Specifically, the series-connected switch tubes U+ and U- constitute the first bridge arm, and the node U of the first bridge arm is connected to the U-phase winding of the motor 2; the series-connected switch tubes V+ and V- constitute the second bridge arm, and the node V of the second bridge arm is connected to the V-phase winding of the motor 2; the series-connected switch tubes W+ and W- constitute the third bridge arm, and the node W of the third bridge arm is connected to the W-phase winding of the motor 2. By controlling the conduction and disconnection of the switch tubes, the corresponding nodes of the three-phase inverter bridge 1 output corresponding electrical signals, thereby driving the motor 2 to run.

[0067] The three current-sensing resistors Rs are arranged corresponding to the three bridge arms of the three-phase inverter bridge 1, and are respectively connected in series between the lower bridge arm of the corresponding bridge arm and the ground. Specifically, one end of the current-sensing resistor Rsu for sampling the U-phase current is grounded, and the other end is connected to the mirror unit 20 and the follower unit 40; one end of the current-sensing resistor Rsv for sampling the V-phase current is grounded, and the other end is connected to the mirror unit 20 and the follower unit 40; one end of the current-sensing resistor Rsw for sampling the W-phase current is grounded, and the other end is connected to the mirror unit 20 and the follower unit 40.

[0068] In this embodiment, the detection voltage is the upper terminal voltage of the current-sensing resistor Rs. When the direction of the current flowing through the current-sensing resistor is from the switch tube to the ground, the direction of the target current flowing through the current-sensing resistor Rs is positive, and the detection voltage is a positive voltage. When the direction of the current flowing through the current-sensing resistor Rs is from the ground to the switch tube, the direction of the target current flowing through the current-sensing resistor is negative, and the detection voltage is a negative voltage. The maximum positive voltage in the detection voltage corresponding to the three-phase bridge arm is output through the cathode connection node of the three second diodes D2, and the maximum positive voltage is compared with the preset voltage threshold through the first comparison unit 30 to realize overcurrent detection of the maximum positive current in the three phases.

[0069] In one embodiment of the present invention, the current detection circuit further includes: a third resistor R3, one end of which is connected to the sampling end of the sampling unit 60, and the other end of which is grounded; and a first capacitor C1, which is connected in parallel with the third resistor R3, so as to filter the input signal of the sampling unit 60 and ensure the detection accuracy.

[0070] In one embodiment of the present invention, the first comparison unit 30 includes: a first comparator A1, wherein the positive input terminal of the first comparator A1 is connected to the output terminal of the mirror unit 20, and the negative input terminal of the first comparator A1 is connected to the providing terminal of the preset voltage threshold; a seventh resistor R7, wherein one end of the seventh resistor R7 is connected to the output terminal of the first comparator A1, and the other end of the seventh resistor R7 is connected to the reference power supply Vdd; and a fifth diode D5, wherein the anode of the fifth diode D5 is connected to the output terminal of the first comparator A1, and the cathode of the fifth diode D5 serves as the output terminal of the first comparison unit 30.

[0071] Specifically, continue with Figure 2 For example, the received mirror voltage is compared with the preset voltage threshold through the first comparator A1. When the mirror voltage is less than the preset voltage threshold, the first comparator A1 outputs a low level, the reference power supply Vdd is grounded through the seventh resistor R7 and the first comparator A1, the fifth diode D5 is not turned on, and no first comparison signal is output. As the target current continues to increase in the positive direction, the mirror voltage gradually increases. When the mirror voltage increases to the preset voltage threshold, the first comparator A1 outputs a high level, the fifth diode D5 is turned on, the reference power supply Vdd is grounded through the seventh resistor R7, the fifth diode D5, and the third resistor R3, and the first comparison unit 30 outputs the first comparison signal to the sampling unit 60 through the connection node of the fifth diode D5 and the third resistor R3.

[0072] In this embodiment, the following formula is satisfied:

[0073] Vc=Vs+Vf1 (1)

[0074] Vcomp11=Vc-Vf2 (2)

[0075]

[0076] Vcomp11=Vcomp12 (4)

[0077] Vf1=Vf2 (5)

[0078] Wherein, Vc is the anode voltage of the first diode, Vs is the detection voltage, Vf1 is the voltage drop of the first diode, Vcomp11 is the positive input voltage of the first comparator, Vf2 is the voltage drop of the second diode, and Vcomp12 is the negative input voltage of the first comparator.

[0079] In this embodiment, the reference power source Vdd is divided by the ninth resistor R9 and the tenth resistor R10 to provide a preset voltage threshold, and the positive input terminal of the first comparator A1 is connected to the connection node of the ninth resistor R9 and the tenth resistor R10.

[0080] Combination Figure 5 As shown, in one embodiment of the present invention, the follower unit 40 includes: a third diode D3, the cathode of the third diode D3 is suitable for connecting to the output end of the detection unit 10; a fourth resistor R4, one end of the fourth resistor R4 is connected to the anode of the third diode D3; a fifth resistor R5, one end of the fifth resistor R5 is connected to the other end of the fourth resistor R4, and has a first node a, and the other end of the fifth resistor R5 is connected to the reference power supply Vdd; a fourth diode D4, the anode of the fourth diode D4 is connected to the first node a; a sixth resistor R6, one end of the sixth resistor R6 is connected to the cathode of the fourth diode D4, and has a second node b, the other end of the sixth resistor R6 is grounded, and the second node b serves as the output end of the follower unit 40.

[0081] Specifically, when the target current flowing through the current-sense resistor Rs is in the first direction or the second direction, the third diode D3 is always turned on, satisfying the following formula:

[0082] Va=R6*I4+Vf4 (6)

[0083]

[0084]

[0085] I4*R6=Vb (10)

[0086] Among them, Va is the voltage of the first node, R6 is the resistance value of the sixth resistor, I4 is the current flowing through the fourth diode and the sixth resistor, Vf4 is the voltage drop of the fourth diode, Vdd is the voltage of the reference power supply, R5 is the resistance value of the fifth resistor, I3 is the current flowing through the third diode and the fourth resistor, Vf3 is the voltage drop of the third diode, Vs is the detection voltage, and Vb is the voltage of the second node.

[0087] Combining the above formulas (6)-(10), it can be seen that when the direction of the target current is the first direction, that is, when the target current is a positive current, as the target current increases in the positive direction, the detection voltage increases in the positive direction, the current I3 flowing through the third diode and the fourth resistor decreases, and the voltage of the first node a increases. Therefore, the current I4 flowing through the fourth diode and the sixth resistor increases, and the follower voltage output by the second node b continues to increase. Therefore, as long as it is ensured that when the detection voltage is 0, the voltage of the second node b is greater than the preset voltage threshold, then when the direction of the target current is the first direction, the second comparison unit 50 can keep not outputting the second comparison signal.

[0088] When the direction of the target current is the second direction, that is, when the target current is a negative current, when the target current increases in the negative direction, the negative direction of the detection voltage increases, the current I3 flowing through the third diode and the fourth resistor continues to increase, and the voltage of the first node a continues to decrease. Therefore, the current I4 flowing through the fourth diode and the sixth resistor continues to decrease, and the follower voltage output by the second node b continues to decrease. When the output voltage of the second node b drops to the preset voltage threshold, the second comparison unit 50 outputs a second comparison signal.

[0089] Further, in the case where the circuit includes three current-sense resistors Rs, as Figure 6 As shown, the follower unit 40 includes three third diodes D3, the cathode of each third diode D3 is respectively connected to the other end of the corresponding current sensing resistor Rs among the three current sensing resistors Rs, and the anodes of the three third diodes D3 are connected together and then connected to one end of the fourth resistor R4.

[0090] The three current-sensing resistors Rs are represented by Rsu, Rsv and Rsw respectively, and the cathodes of the three third diodes D3 receive the detection voltages output by the three current-sensing resistors Rs respectively, and the detection voltages output by the current-sensing resistors Rsu, Rsv and Rsw are represented by Vsu, Vsv and Vsw respectively. Among them, the anode voltages of the three third diodes D3 are Vsu+Vf3, Vsv+Vf3, Vsw+Vf3 respectively.

[0091] The voltage at the node formed by the anode connection of the three third diodes D3 is the minimum voltage among the three anode voltages, that is, the minimum voltage among the three anode voltages is output through the anode connection node of the three third diodes D3, and the voltage of the second node b is adjusted based on the minimum voltage, so as to control the second comparison unit 50 to generate a second comparison signal. Since the minimum voltage among the three anode voltages is determined based on the minimum voltage among the three detection voltages, that is, the minimum current of the target current in the second direction flowing through the three current-sensing resistors is determined, wherein when the target current is in the second direction, the target current is a negative current, and the smaller the target current is, the larger the current value in the negative direction is, and the detection voltage is a negative voltage, and the smaller the detection voltage is, the larger the voltage value in the negative direction is, thus, the second comparison unit 50 can control the output of the second comparison signal based on the minimum current flowing through the three current-sensing resistors, that is, the maximum negative current, and the sampling unit 60 can judge the overcurrent state of the negative maximum current among the three target currents based on the second comparison signal to determine whether there is a negative overcurrent among the three target currents.

[0092] In one embodiment of the present invention, the second comparison unit 50 includes: a second comparator A2, wherein the negative input terminal of the second comparator A2 is connected to the output terminal of the follower unit 40, and the positive input terminal of the second comparator A2 is connected to the providing terminal of the preset voltage threshold; an eighth resistor R8, wherein one end of the eighth resistor R8 is connected to the output terminal of the second comparator A2, and the other end of the eighth resistor R8 is connected to the reference power supply Vdd; a sixth diode D6, wherein the anode of the sixth diode D6 is connected to the output terminal of the second comparator A2, and the cathode of the sixth diode D6 serves as the output terminal of the second comparison unit 50.

[0093] Specifically, the received following voltage is compared with the preset voltage threshold through the second comparator A2. When the following voltage is less than the preset voltage threshold, the second comparator A outputs a low level, the reference power supply Vdd is grounded through the eighth resistor R8 and the second comparator A2, the sixth diode D6 is not turned on, and the second comparison signal is not output. As the target current continues to increase in the negative direction, the following voltage gradually decreases. When the following voltage decreases to the preset voltage threshold, the second comparator A2 outputs a high level, the sixth diode D6 is turned on, the reference power supply Vdd is grounded through the eighth resistor R8, the sixth diode D6, and the third resistor R3, and the second comparison unit 50 outputs the second comparison signal to the sampling unit 60 through the connection node of the sixth diode D6 and the third resistor R3.

[0094] Continuing with the example of dividing the reference power source Vdd by the ninth resistor R9 and the tenth resistor R10 to provide a preset voltage threshold, when outputting the second comparison signal, the circuit satisfies the following formula:

[0095] Vcomp21=Vcomp22 (11)

[0096] Vcomp21+Vf4=Va (12)

[0097] Vcomp21=I4*R6 (13)

[0098]

[0099]

[0100]

[0101] Vs=Is*Rs (17)

[0102] Among them, Vcomp21 is the negative input terminal voltage of the second comparator, Vcomp22 is the positive input terminal voltage of the second comparator, Vf4 is the voltage drop of the fourth diode, Va is the voltage of the first node, I4 is the current flowing through the fourth diode and the sixth resistor, R6 is the resistance value of the sixth resistor, R10 is the resistance value of the tenth resistor, Vdd is the voltage of the reference power supply, R9 is the resistance value of the ninth resistor, Vs is the detection voltage, Vf3 is the voltage drop of the third diode, I3 is the current flowing through the third diode and the fourth resistor, Is is the target current, and Rs is the resistance value of the current sensing resistor.

[0103] The above formulas (11)-(17) can be combined to set a second target current threshold for triggering the second comparator A2 to output a second comparison signal. When the target current drops to the second target current threshold, it is considered that a negative overcurrent occurs in the target current, and the voltage at the negative input terminal of the second comparator A2 is equal to the voltage at the positive input terminal of the second comparator A2. The second comparison unit 50 sends a second comparison signal to the sampling unit 60.

[0104] In one embodiment of the present invention, the sampling unit 60 includes a controller 61 , and a sampling terminal of the controller 61 is connected to an output terminal of the first comparison unit 30 and an output terminal of the second comparison unit 50 , respectively.

[0105] Specifically, the following Figure 7 and Fig.10 The working process of the current detection circuit of the present application is described with examples.

[0106] Figure 7 FIG. 1 is a schematic diagram of a current detection circuit using a current sensing resistor Rs.

[0107] The direction of the target current is as follows Figure 8In the first direction shown, when the target current is a positive current, the voltage at the upper end of the current-sensing resistor Rs is a positive voltage, that is, the detection voltage is a positive voltage, and as the positive current increases, the detection voltage increases in the positive direction. The first diode D1 and the second diode D2 are turned on, and the mirror unit 20 outputs the mirror voltage to the first comparison unit 30, and the mirror voltage is compared with the divided voltage provided by the eighth resistor R8 and the ninth resistor R9, that is, the preset voltage threshold, through the first comparison unit 30. When the mirror voltage is less than the preset voltage threshold, the first comparator A1 outputs a low level, and the first comparison unit 30 does not output the first comparison signal until the mirror voltage increases to the preset voltage threshold, the first comparator A1 outputs a high level, and the reference power supply Vdd is grounded through the seventh resistor, the fifth diode and the third resistor R3, thereby, the first comparison unit 30 outputs the first comparison signal to the controller 61.

[0108] At the same time, when the direction of the target current is the first direction, the third diode D3 is turned on, but the voltage of the second node b is continuously greater than the preset voltage threshold, the second comparator A2 outputs a low level, and the second comparison unit 50 does not work. Therefore, when the direction of the target current is the first direction, the sampling unit 60 only receives the first comparison signal and determines the overcurrent state of the target current according to the first comparison signal.

[0109] The direction of the target current is as follows Fig. 9 In the second direction shown, when the target current is a negative current, the voltage at the upper end of the current-sense resistor Rs is a negative voltage, that is, the detection voltage is a negative voltage, and as the negative current increases, the detection voltage increases in a negative direction. In the mirror unit 20, the first diode D1 is turned on, the second diode D2 is not turned on, and the mirror unit 20 does not output the mirror voltage. Therefore, when the direction of the target current is the second direction, the first comparison unit 30 does not work.

[0110] At the same time, the third diode D3 is turned on, and when the voltage at the second node b drops to a preset voltage threshold, the second comparator A2 outputs a high level, the reference power supply Vdd is grounded through the eighth resistor R8, the sixth diode D6, and the third resistor R3, and the second comparison unit A2 outputs a second comparison signal to the sampling unit 60. Therefore, when the direction of the target current is the second direction, the sampling unit 60 only receives the second comparison signal, and determines the overcurrent state of the target current according to the second comparison signal.

[0111] Fig.10 The schematic diagram of the current detection circuit using three current sensing resistors is shown in FIG. Figure 4 The motor drive circuit shown.

[0112] During the motor current sampling process, the currents flowing through the three current-sensing resistors are Iu, Iv, and Iw, respectively, and satisfy Iu+Iv+Iw=0. When one-phase current is positive and the other two-phase currents are negative, the positive current is larger and the negative current is smaller, and there is a risk of positive overcurrent; when one-phase current is negative and the other two-phase currents are positive, the negative current is larger and the positive current is smaller, and there is a risk of negative overcurrent.

[0113] Assuming that Iu is a positive current and Iv and Iw are negative currents, the second diode D2 corresponding to the V phase and W phase is not conducting, and the mirror voltage received by the first comparison unit 30 is Vsu. The first comparison unit 30 outputs a first comparison signal to the controller 61 based on the voltage. At the same time, Iv and Iw are smaller negative voltages, so the follower voltage is greater than the preset voltage threshold, and the second comparison unit 50 does not output. Therefore, the sampling unit 60 determines whether an overcurrent occurs based on the received first comparison signal.

[0114] Assuming that Iu is a negative current, and Iv and Iw are positive currents, then the second diode D2 corresponding to U is not conducting, and the second diode D2 corresponding to V phase and W is conducting. At this time, the mirror image output by the cathode connection node of the three second diodes D2 is the maximum voltage of Vsv and Vsw, so the positive current of the two phases is small, so the mirror voltage cannot reach the preset voltage threshold, and the first comparison unit 30 does not output. At the same time, when the negative current of the U phase is small, the second comparator A2 still outputs a low level until the follower voltage drops to the preset voltage threshold, the second comparator A2 outputs a high level, and the second comparison unit 50 outputs a second comparison signal to the controller 61, and the sampling unit 60 performs overcurrent judgment according to the second comparison signal.

[0115] This embodiment can realize positive and negative overcurrent detection of three-phase sampling by adding a small number of devices, and is also applicable to the case where there is no built-in comparator in the chip.

[0116] In one embodiment of the present invention, the first comparison unit 30 and the second comparison unit 50 can be integrated into the MCU of the controller 61, thereby directly using the internal comparator of the MCU for circuit layout, which can better achieve protection and reduce costs. In addition, when the first comparison unit 30 and the second comparison unit 50 are integrated into the MCU, the sampling unit 20 can directly judge the overcurrent state through the high and low levels output by the first comparator A1 and the second comparator A2.

[0117] In summary, according to the current detection circuit of the embodiment of the present invention, the target current is detected by the detection unit to generate a detection voltage, the mirror unit mirrors the detection voltage when the direction of the target current is a first direction, and outputs the mirror voltage, the first comparison unit compares the mirror voltage to output a first comparison signal when the mirror voltage rises to a preset voltage threshold, the following unit follows the detection voltage when the direction of the target current is a second direction, and outputs a following voltage, wherein the second direction is opposite to the first direction, the second comparison unit compares the following voltage to output a second comparison signal when the following voltage drops to a preset voltage threshold, and the sampling unit samples the first comparison signal and the second comparison signal to determine the overcurrent state of the target current. Thus, the circuit

[0118] Corresponding to the above embodiment, the present invention also proposes an overcurrent protection device.

[0119] like Fig.11 As shown, the overcurrent protection device of the embodiment of the present invention includes: the above-mentioned current detection circuit 100 and the controller 200, wherein the current detection circuit 100 is suitable for detecting the target current to determine the overcurrent state of the target current. The controller 200 is configured to generate an overcurrent protection signal according to the overcurrent state.

[0120] Specifically, the current detection circuit 100 detects the target current and sends the determined overcurrent state of the target current to the controller 200. When the controller 200 determines that the target current is overcurrent according to the overcurrent state, it sends an overcurrent protection signal to trigger the overcurrent protection action and perform overcurrent protection control on the target circuit to ensure the overcurrent protection effect. For example, when the overcurrent protection device is applied to motor overcurrent protection, the specific connection method of the overcurrent detection circuit 100 can refer to the above Figure 4 After the sampling unit 60 of the current detection circuit 100 sends the confirmed overcurrent state to the controller 200, the controller 200 outputs a corresponding overcurrent protection signal when determining that a current overcurrent occurs according to the overcurrent state, so as to control the output disconnection of the three-phase inverter bridge 1, complete the overcurrent protection of the motor 2, and ensure the stability of the motor operation.

[0121] For example, combining Fig.12As shown, the controller 200 and the sampling unit 60 of the current detection circuit 100 are integrated in the chip of the IPM (Intelligent Power Module) module, wherein the output end of the IPM module is connected to the motor, and the control end of the IPM module is connected to the MCU to receive the PWM (Pulse width modulation) signal output by the MCU, and control the internal switch tube through the PWM signal to output the corresponding three-phase electrical signal to drive the motor to operate.

[0122] The three current-sensing resistors Rsu, Rsv, and Rsw are connected between the corresponding chip pins NU, NV, and NW of the three bridge arms of the IPM module and the ground, so as to realize the sampling of the three-phase current and generate the corresponding detection voltage. The chip pin RS of the IPM module is the input end of the sampling unit 60, and the controller 200 is connected to the sampling unit 60. The sampling unit 60 detects the overcurrent state of the target current in different directions based on the first comparison signal and the second comparison signal, and sends it to the controller 200. When the controller 200 determines that an overcurrent occurs according to the received overcurrent state, it controls the output of the IPM module to disconnect and sends an overcurrent reminder to the MCU to stop the MCU from outputting the PWM signal to complete the overcurrent protection.

[0123] Therefore, in the absence of a built-in comparator in the MCU chip, this application can also achieve three-phase sampling positive and negative current overcurrent protection by adding a minimum of components, effectively protecting the IPM module and motor while reducing application costs.

[0124] According to the overcurrent protection device of the embodiment of the present invention, the target current is detected by the above-mentioned current detection circuit to determine the overcurrent state of the target current. The controller generates an overcurrent protection signal according to the overcurrent state. Based on the above-mentioned current detection circuit, the overcurrent state detection under different current directions can be completed, thereby ensuring the positive and negative overcurrent protection effects.

[0125] Corresponding to the above embodiment, the present invention further proposes an intelligent power module.

[0126] like Fig.13 As shown, the intelligent power module 300 of the embodiment of the present invention includes: a three-phase inverter bridge 310 and a current detection circuit 100, wherein the three-phase inverter bridge 310 includes a three-phase bridge arm, each phase arm in the three-phase bridge arm includes an upper bridge switch tube and a lower bridge switch tube, and the current detection circuit 100 is suitable for sampling the positive and negative current of each phase of the three-phase inverter bridge 310.

[0127] In one embodiment of the present invention, when the current detection circuit 100 includes a current detection resistor, one end of the current detection resistor is grounded, and the other end of the current detection resistor is connected to the lower bridge switch tube in each phase bridge arm.

[0128] In one embodiment of the present invention, when the current detection circuit 100 includes three current detection resistors, one end of each current detection resistor is grounded, and the other end of each current detection resistor is connected to a corresponding lower bridge switch tube in each phase bridge arm.

[0129] According to the intelligent power module of the embodiment of the present invention, the three-phase inverter bridge includes a three-phase bridge arm, and each phase arm of the three-phase bridge arm includes an upper bridge switch tube and a lower bridge switch tube respectively. The above-mentioned current detection circuit samples the positive and negative current of each phase of the three-phase inverter bridge. Therefore, based on the above-mentioned current detection circuit, overcurrent state detection under different current directions can be completed, so that it meets the positive and negative overcurrent detection requirements of the intelligent power module, and effectively protects the intelligent power module.

[0130] Corresponding to the above embodiment, the present invention also proposes a household appliance.

[0131] like Fig.14 As shown, the household appliance 400 according to the embodiment of the present invention includes a motor 410 and the above-mentioned intelligent power module 300 , and the intelligent power module 300 is suitable for driving the motor.

[0132] According to the household appliance of the embodiment of the present invention, the motor is driven by the above-mentioned intelligent power module. Based on the above-mentioned intelligent power module, overcurrent state detection under different current directions can be completed, so that it meets the positive and negative overcurrent detection requirements, improves the overcurrent protection effect, and ensures the operating stability of the household appliance.

[0133] In the description of this specification, the description with reference to the terms "one embodiment", "some embodiments", "examples", "specific examples", or "some examples" means that the specific features, structures, materials or characteristics described in conjunction with the embodiment or example are included in at least one embodiment or example of the present invention. In this specification, the schematic representation of the above terms does not necessarily refer to the same embodiment or example. Moreover, the specific features, structures, materials or characteristics described may be combined in any one or more embodiments or examples in a suitable manner.

[0134] In addition, the terms "first" and "second" are used for descriptive purposes only and should not be understood as indicating or implying relative importance or implicitly indicating the number of the indicated technical features. Therefore, the features defined as "first" and "second" may explicitly or implicitly include at least one of the features. In the description of the present invention, the meaning of "plurality" is at least two, such as two, three, etc., unless otherwise clearly and specifically defined.

[0135] In the present invention, unless otherwise clearly specified and limited, the terms "installed", "connected", "connected", "fixed" and the like should be understood in a broad sense, for example, it can be a fixed connection, a detachable connection, or an integral connection; it can be a mechanical connection or an electrical connection; it can be a direct connection or an indirect connection through an intermediate medium, it can be the internal connection of two elements or the interaction relationship between two elements, unless otherwise clearly defined. For ordinary technicians in this field, the specific meanings of the above terms in the present invention can be understood according to specific circumstances.

[0136] Although the embodiments of the present invention have been shown and described above, it is to be understood that the above embodiments are exemplary and are not to be construed as limitations of the present invention. A person skilled in the art may change, modify, replace and vary the above embodiments within the scope of the present invention.

Claims

1. A current detection circuit, characterized in that: include: A detection unit, adapted to detect a target current to generate a detection voltage; a mirror unit, adapted to mirror the detection voltage and output a mirror voltage when the direction of the target current is a first direction; A first comparison unit, adapted to compare the mirror voltage, so as to output a first comparison signal when the mirror voltage rises to a preset voltage threshold; a following unit, adapted to follow the detection voltage and output a following voltage when the direction of the target current is a second direction, wherein the second direction is opposite to the first direction; A second comparison unit, adapted to compare the following voltage, so as to output a second comparison signal when the following voltage drops to a preset voltage threshold; The sampling unit is configured to sample the first comparison signal and the second comparison signal to determine an overcurrent state of the target current.

2. The current detection circuit according to claim 1, characterized in that: The detection unit includes at least one current-sensing resistor, one end of the current-sensing resistor is grounded, and the other end of the current-sensing resistor serves as an output end of the detection unit.

3. The current detection circuit according to claim 2, characterized in that: The mirror unit includes a first diode, a second diode and a first resistor, wherein an anode of the first diode is connected to an anode of the second diode and then connected to one end of the first resistor, the other end of the first resistor is connected to a reference power supply, a cathode of the first diode is connected to an output end of the detection unit, and a cathode of the second diode is suitable for connecting to the first comparison unit.

4. The current detection circuit according to claim 3, characterized in that: When there are three current-sense resistors, there are three mirror units, wherein: The cathode of the first diode in each of the mirror units is respectively connected to the other end of the corresponding current sensing resistor among the three current sensing resistors; The cathodes of the second diodes in the three mirror units are connected together to serve as the output end of the mirror unit.

5. The current detection circuit according to claim 3, characterized in that: The mirroring unit also includes: A second resistor, one end of the second resistor is connected to the cathode of the second diode, and the other end of the second resistor is grounded.

6. The current detection circuit according to any one of claims 1 to 5, characterized in that: Also includes: a third resistor, one end of the third resistor being connected to the sampling end of the sampling unit, and the other end of the third resistor being grounded; A first capacitor is connected in parallel with the third resistor.

7. The current detection circuit according to any one of claims 1 to 5, characterized in that: The following unit comprises: a third diode, wherein a cathode of the third diode is suitable for connecting to an output terminal of the detection unit; a fourth resistor, one end of which is connected to the anode of the third diode; a fifth resistor, one end of the fifth resistor being connected to the other end of the fourth resistor and having a first node, and the other end of the fifth resistor being connected to a reference power supply; a fourth diode, wherein an anode of the fourth diode is connected to the first node; A sixth resistor, one end of which is connected to the cathode of the fourth diode and has a second node, the other end of which is grounded, and the second node serves as the output end of the follower unit.

8. The current detection circuit according to any one of claims 1 to 5, characterized in that: The first comparison unit comprises: A first comparator, wherein a positive input terminal of the first comparator is connected to an output terminal of the mirror unit, and a negative input terminal of the first comparator is connected to a providing terminal of a preset voltage threshold; a seventh resistor, one end of the seventh resistor being connected to the output end of the first comparator, and the other end of the seventh resistor being connected to a reference power supply; A fifth diode, wherein an anode of the fifth diode is connected to the output end of the first comparator, and a cathode of the fifth diode serves as the output end of the first comparison unit.

9. The current detection circuit according to any one of claims 1 to 5, characterized in that: The second comparison unit comprises: A second comparator, wherein a negative input terminal of the second comparator is connected to the output terminal of the follower unit, and a positive input terminal of the second comparator is connected to a supply terminal of a preset voltage threshold; an eighth resistor, one end of the eighth resistor being connected to the output end of the second comparator, and the other end of the eighth resistor being connected to a reference power supply; A sixth diode, wherein an anode of the sixth diode is connected to the output end of the second comparator, and a cathode of the sixth diode serves as the output end of the second comparison unit.

10. The current detection circuit according to claim 6, characterized in that: The sampling unit includes a controller, and a sampling end of the controller is connected to an output end of the first comparing unit and an output end of the second comparing unit respectively.

11. The current detection circuit according to claim 10, characterized in that: The first comparison unit and the second comparison unit may be integrated into an MCU of the controller.

12. An overcurrent protection device, characterized in that: include: The current detection circuit according to any one of claims 1 to 11, adapted to detect the target current to determine an overcurrent state of the target current; The controller is configured to generate an overcurrent protection signal according to the overcurrent state.

13. An intelligent power module, characterized in that: include: A three-phase inverter bridge, wherein the three-phase inverter bridge comprises three-phase bridge arms, and each phase bridge arm of the three-phase bridge arms comprises an upper bridge switch tube and a lower bridge switch tube; According to any one of claims 1-11, the current detection circuit is suitable for detecting the positive and negative current of each phase of the three-phase inverter bridge.

14. The intelligent power module according to claim 13, characterized in that: In the case where the current detection circuit includes a current detection resistor, one end of the current detection resistor is grounded, and the other end of the current detection resistor is respectively connected to the lower bridge switch tube in each phase bridge arm.

15. The intelligent power module according to claim 13, characterized in that: When the current detection circuit includes three current detection resistors, one end of each current detection resistor is grounded, and the other end of each current detection resistor is connected to a corresponding lower bridge switch tube in each phase bridge arm.

16. A household appliance, characterized in that: include: Motor; The intelligent power module according to any one of claims 13 to 15, wherein the intelligent power module is suitable for driving the motor.

Images