Current detection circuit and device of bidirectional DCDC converter

Abstract

The invention discloses a current detection circuit and device of a bidirectional DCDC converter, and relates to the technical field of current detection.The current detection circuit comprises a current sampling circuit and an operational amplifier circuit, the current sampling circuit is connected with the bidirectional DCDC converter and used for converting current of the bidirectional DCDC converter into positive voltage or negative voltage according to current induction, and the operational amplifier circuit is connected with the bidirectional DCDC converter; the input end of the operational amplifier circuit is connected with the output end of the current sampling circuit, and the operational amplifier circuit is used for converting the positive voltage or the negative voltage of the current sampling circuit into the positive voltage and outputting the positive voltage to a post-stage closed-loop control circuit and an overcurrent protection circuit. The current of the bidirectional DC-DC converter is acquired through the single current sampling circuit and is simultaneously used as the input of the closed-loop control circuit and the overcurrent protection circuit, and the current value of the bidirectional DC-DC converter is acquired without using two sets of different current sampling circuits, namely a Hall detection chip and a current transformer, so that the circuit is simplified, the acquisition and processing speed of the circuit is improved, and the cost is reduced. And the manufacturing cost of the circuit is reduced.

Description

Technical Field

[0001] The present invention relates to the technical field of current detection, and in particular to a bidirectional DC / DC current detection circuit and device. Background Art

[0002] A bidirectional DC-DC converter is a type of bidirectional DC-DC converter that achieves dual-quadrant operation by changing the direction of current according to actual needs while maintaining the polarity of the input and output voltages. As new energy vehicles gradually begin to use bidirectional DC-DC converters to replace unidirectional DC-DC converters, it is crucial to collect the current of the bidirectional DC-DC converter to detect current changes in the circuit.

[0003] In the prior art, a bidirectional current Hall effect detection chip is typically used to detect the input and output currents of a bidirectional DCDC converter as input signals for a closed-loop control circuit. A current transformer coupled with a full-wave rectifier circuit is then used to detect the current of the bidirectional DCDC converter as input signals for an overcurrent protection circuit. Due to the slow response speed of the current Hall effect detection chip, it is not suitable for overcurrent protection circuits. Furthermore, the voltage drop in the diodes in the current transformer coupled with the full-wave rectifier circuit can easily cause distortion in the low-voltage portion of the sampled signal, making it unsuitable for closed-loop control circuits.

[0004] However, using two different current sampling circuits, namely a Hall detection chip and a current transformer, to collect the current value of the bidirectional DCDC converter results in a complex circuit and increases the manufacturing cost of the circuit. Summary of the Invention

[0005] Embodiments of the present invention provide a current detection circuit and device for a bidirectional DC-DC converter to address the technical problem in related technologies of using two different current sampling circuits, namely a Hall detection chip and a current transformer, to collect the current value of a bidirectional DC-DC converter, resulting in a complex circuit and increased circuit manufacturing cost.

[0006] In a first aspect, a current detection circuit for a bidirectional DCDC converter is provided, comprising: Current sampling circuit and operational amplifier circuit; The current sampling circuit is connected to the bidirectional DCDC converter and is used to convert the current of the bidirectional DCDC converter into a positive voltage or a negative voltage according to current sensing; The input end of the operational amplifier circuit is connected to the output end of the current sampling circuit, and is used to convert the positive voltage or negative voltage of the current sampling circuit into a positive voltage and output it to the subsequent closed-loop control circuit and overcurrent protection circuit.

[0007] In some embodiments, the current sampling circuit includes: A current sensing sensor, the current sensing sensor is connected to the bidirectional DCDC converter, and an output end of the current sensing sensor is connected to the operational amplifier circuit; A sampling resistor, wherein a first end of the sampling resistor is connected to the output end of the current sensing sensor and the input end of the operational amplifier circuit, and a second end of the sampling resistor is grounded.

[0008] In some embodiments, the current sensing sensor is a Hall effect current sensor or a current transformer.

[0009] In some embodiments, the sampling resistor is a precision current sampling resistor.

[0010] In some embodiments, the current sampling circuit further includes: a first capacitor, wherein a first end of the first capacitor is connected to the positive power supply terminal of the current sensing sensor, and a second end of the first capacitor is grounded; A second capacitor, wherein a first end of the second capacitor is connected to the negative power supply end of the current sensing sensor, and a second end of the second capacitor is grounded.

[0011] In some embodiments, the operational amplifier circuit includes: a first operational amplifier unit, the first operational amplifier unit being connected to the output end of the current sensing sensor and the first end of the sampling resistor; The second operational amplifier unit is connected to the output end of the first operational amplifier unit and the output end of the current sensing sensor respectively, and is used to convert the positive voltage or negative voltage collected by the sampling resistor into a positive voltage and output it to the closed-loop control circuit and the overcurrent protection circuit.

[0012] In some embodiments, the first operational amplifier unit includes: a first operational amplifier, a third resistor, a first diode, a second diode, and a second resistor and a fourth resistor of the same resistance value, wherein the first end of the second resistor is connected to the output end of the current sensing sensor and the first end of the sampling resistor, the second end of the second resistor is connected to the inverting input end of the first operational amplifier, the first end of the third resistor is connected to the non-inverting input end of the first operational amplifier, the second end of the third resistor is grounded, the first end of the fourth resistor is connected to the inverting input end of the first operational amplifier, the second end of the fourth resistor is connected to the anode of the second diode, the anode of the second diode is connected to the second operational amplifier unit, the cathode of the second diode is connected to the output end of the first operational amplifier, the anode of the first diode is connected to the output end of the first operational amplifier and the cathode of the second diode, and the cathode of the first diode is connected to the inverting input end of the first operational amplifier and the first end of the second resistor.

[0013] In some embodiments, the second operational amplifier unit includes: a seventh resistor, an eighth resistor, a second operational amplifier, and a fifth resistor and a sixth resistor having the same resistance; The resistance of the sixth resistor is twice the resistance of the seventh resistor; The first end of the seventh resistor is connected to the anode of the second diode, the second end of the seventh resistor is connected to the inverting input terminal of the second operational amplifier, the first end of the fifth resistor is connected to the first end of the second resistor, the second end of the fifth resistor is connected to the second end of the seventh resistor and the inverting input terminal of the second operational amplifier, the first end of the sixth resistor is connected to the second end of the fifth resistor, the second end of the seventh resistor, and the inverting input terminal of the second operational amplifier, the second end of the sixth resistor is connected to the output terminal of the second operational amplifier, the output terminal of the second operational amplifier is respectively connected to the closed-loop control circuit and the overcurrent protection circuit, the first end of the eighth resistor is connected to the non-inverting input terminal of the second operational amplifier, and the second end of the eighth resistor is grounded.

[0014] In some embodiments, the first operational amplifier and the second operational amplifier are OPA602.

[0015] In a second aspect, a current detection device for a bidirectional DCDC converter is provided, comprising the aforementioned current detection circuit for the bidirectional DCDC converter.

[0016] The beneficial effects brought about by the technical solution provided by the present invention include: Embodiments of the present invention provide a current detection circuit and device for a bidirectional DC-DC converter. The current detection circuit of the bidirectional DC-DC converter includes a current sampling circuit and an operational amplifier circuit. The current sampling circuit is connected to the bidirectional DC-DC converter and is configured to convert the current of the bidirectional DC-DC converter into a positive voltage or a negative voltage based on current sensing. The input end of the operational amplifier circuit is connected to the output end of the current sampling circuit and is configured to convert the positive or negative voltage of the current sampling circuit into a positive voltage and output the converted voltage to a subsequent closed-loop control circuit and an overcurrent protection circuit. The current of the bidirectional DC-DC converter is collected by a single current sampling circuit and simultaneously serves as an input to the closed-loop control circuit and the overcurrent protection circuit. This eliminates the need for two separate current sampling circuits, namely a Hall detection chip and a current transformer, to collect the current value of the bidirectional DC-DC converter. This simplifies the circuit, improves the circuit acquisition and processing speed, and reduces the circuit manufacturing cost. BRIEF DESCRIPTION OF THE DRAWINGS

[0017] In order to more clearly illustrate the technical solutions in the embodiments of the present invention, the following briefly introduces the drawings required for use in the description of the embodiments. Obviously, the drawings described below are only some embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without creative work.

[0018] Figure 1 A block diagram of a current detection circuit for a bidirectional DCDC converter provided by an embodiment of the present invention; Figure 2 This is a schematic diagram of a current detection circuit for a bidirectional DCDC converter provided by an embodiment of the present invention. DETAILED DESCRIPTION

[0019] To make the objectives, technical solutions, and advantages of the embodiments of the present invention more clear, the technical solutions in the embodiments of the present invention will be clearly and completely described below in conjunction with the accompanying drawings in the embodiments of the present invention. Obviously, the described embodiments are part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without making creative efforts shall fall within the scope of protection of the present invention.

[0020] An embodiment of the present invention provides a current detection circuit for a bidirectional DCDC converter, which can solve the technical problem in the related art of using two different current sampling circuits, namely a Hall detection chip and a current transformer, to collect the current value of the bidirectional DCDC converter, resulting in a complex circuit and increased circuit manufacturing cost.

[0021] Figure 1 A current detection circuit for a bidirectional DCDC converter provided in an embodiment of the present invention includes: a current sampling circuit and an operational amplifier circuit. The current sampling circuit is connected to the bidirectional DCDC converter and is used to convert the current of the bidirectional DCDC converter into a positive voltage or a negative voltage based on current sensing. The input end of the operational amplifier circuit is connected to the output end of the current sampling circuit and is used to convert the positive or negative voltage of the current sampling circuit into a positive voltage and output it to a subsequent closed-loop control circuit and overcurrent protection circuit.

[0022] A current detection circuit for a bidirectional DCDC converter according to an embodiment of the present invention includes a current sampling circuit and an operational amplifier circuit. The current sampling circuit is connected to the bidirectional DCDC converter and is configured to convert the current of the bidirectional DCDC converter into a positive voltage or a negative voltage based on current sensing. The input end of the operational amplifier circuit is connected to the output end of the current sampling circuit and is configured to convert the positive or negative voltage of the current sampling circuit into a positive voltage and output the converted voltage to a subsequent closed-loop control circuit and an overcurrent protection circuit. The present invention uses the current sampling circuit to collect the current of the bidirectional DCDC converter based on current sensing. The current collection response speed is fast and the circuit is suitable for overcurrent protection circuits. At the same time, the positive voltage or negative voltage output by the current sampling circuit is converted into a positive voltage by the operational amplifier circuit. There is no voltage drop and no distortion of the low-voltage portion of the sampling signal. The present invention is also suitable for closed-loop control circuits. The current sampling circuit can collect the current of the bidirectional DCDC converter and simultaneously serve as the input of the closed-loop control circuit and the overcurrent protection circuit through a single current sampling circuit. There is no need to use two different current sampling circuits, namely a Hall detection chip and a current transformer, to collect the current value of the bidirectional DC-DC converter. This simplifies the circuit, improves the circuit collection and processing speed, and reduces the circuit manufacturing cost.

[0023] As an optional implementation, in one embodiment of the invention, see Figure 1 and Figure 2 As shown, the current sampling circuit includes: a current sensing sensor and a sampling resistor R1. The current sensing sensor is connected to the bidirectional DC-DC converter. The output end of the current sensing sensor is connected to the operational amplifier circuit. The first end of the sampling resistor R1 is connected to the output end of the current sensing sensor and the input end of the operational amplifier circuit. The second end of the sampling resistor R1 is grounded. The current sensing sensor detects the current of the bidirectional DC-DC converter. Since the input and output current values ​​of the bidirectional DC-DC converter can be positive or negative, the current sensing sensor can also detect positive or negative current values. The sampling resistor R1 converts the positive current value of the current sensing sensor into a positive voltage value and the negative current value into a negative voltage value. The positive or negative voltage is converted into a positive voltage by the operational amplifier circuit and then output to the subsequent closed-loop control circuit and overcurrent protection circuit. The current sensing sensor has a relatively fast detection and response speed, which can meet the fast response requirements of the overcurrent protection circuit.

[0024] As an optional implementation, in one embodiment of the invention, see Figure 1 and Figure 2As shown, the current sensing sensor is a Hall effect current sensor or a current transformer. The Hall effect current sensor model is LA125P. The Hall effect current sensor has a fast detection response speed and a wide detection range. The detection range can reach positive and negative several thousand amperes. It can monitor the magnitude and direction of the input or output current of the bidirectional DCDC converter in real time, monitor the current and power of the power supply equipment, and realize accurate power measurement and current overload protection. The current transformer detects current through the principle of electromagnetic induction, with a wide detection range and high detection accuracy.

[0025] As an optional implementation, in one embodiment of the invention, see Figure 1 and Figure 2 As shown, the sampling resistor R1 is a precision current sampling resistor with an accuracy of ±0.1%. The precision current sampling resistor has the advantages of high precision, low error, low resistance, high stability and fast response. It can monitor the input or output current of the bidirectional DCDC converter in real time to achieve overcurrent protection and constant current output. The power consumption in the circuit is also extremely small, which will not affect the circuit efficiency.

[0026] As an optional implementation, in one embodiment of the invention, see Figure 1 and Figure 2 As shown, the current sampling circuit also includes: a first capacitor C1 and a second capacitor C2, wherein the first end of the first capacitor C1 is connected to the positive power supply terminal of the current sensing sensor, the second end of the first capacitor C1 is grounded, the first end of the second capacitor C2 is connected to the negative power supply terminal of the current sensing sensor, and the second end of the second capacitor C2 is grounded. The first capacitor C1 and the second capacitor C2 are both decoupling capacitors for suppressing noise and voltage fluctuations in the input and output currents of the bidirectional DCDC converter. When the circuit current suddenly changes, the decoupling capacitor quickly releases the stored charge to compensate for transient current demand and maintain voltage stability; it is also used to stabilize the voltage supply and prevent signal interference. By placing the decoupling capacitor nearby, a low-impedance return path is provided for high-frequency interference, crosstalk is reduced, and the reliability and stability of the circuit are improved. In addition, the capacitance of the first capacitor C1 and the second capacitor C2 can be 0.1uF.

[0027] As an optional implementation, in one embodiment of the invention, see Figure 1 and Figure 2As shown, the operational amplifier circuit includes: a first operational amplifier unit and a second operational amplifier unit, the first operational amplifier unit is connected to the output end of the current sensing sensor and the first end of the sampling resistor, and the second operational amplifier unit is respectively connected to the output end of the first operational amplifier unit and the output end of the current sensing sensor, and is used to convert the positive voltage or negative voltage collected by the sampling resistor R1 into a positive voltage and output it to the closed-loop control circuit and the overcurrent protection circuit; when the current sampling circuit converts the current of the bidirectional DCDC converter into a positive voltage VR1, the input end VR1 of the first operational amplifier unit is a positive voltage, the output end of the first operational amplifier unit is a negative voltage -V1, and the input end V2 of the second operational amplifier unit is a voltage equal to the inverting input end of the first operational amplifier unit. V4 are equal, the output terminal V3 of the second operational amplifier unit is also a positive voltage and equal to the input terminal VR1 of the first operational amplifier unit; when the current sampling circuit converts the current of the bidirectional DCDC converter into a negative voltage -VR1, the input terminal of the first operational amplifier unit is a negative voltage -VR1, the output terminal of the first operational amplifier unit is a positive voltage V1, the input terminal V2 of the second operational amplifier unit is equal to the input terminal -VR1 of the first operational amplifier unit, and the output terminal V3 of the second operational amplifier unit is also equal to -VR1. Then, the positive voltage or negative voltage of the current sampling circuit is converted into a positive voltage output through the first operational amplifier unit and the second operational amplifier unit, which can be used as the input signal of the closed-loop control circuit and the input signal of the overcurrent protection circuit.

[0028] As an optional implementation, in one embodiment of the invention, see Figure 2 As shown, the first operational amplifier unit includes: a first operational amplifier U1, a third resistor R3, a first diode D1, a second diode D2, and a second resistor R2 and a fourth resistor R4 of the same resistance value. The first end of the second resistor R2 is connected to the output end of the current sensing sensor and the first end of the sampling resistor R1, the second end of the second resistor R2 is connected to the inverting input end of the first operational amplifier U1, the first end of the third resistor R3 is connected to the non-inverting input end of the first operational amplifier U1, the second end of the third resistor R3 is grounded, the first end of the fourth resistor R4 is connected to the inverting input end of the first operational amplifier U1, the second end of the fourth resistor R4 is connected to the anode of the second diode D2, the anode of the second diode D2 is connected to the second operational amplifier unit, the cathode of the second diode D2 is connected to the output end of the first operational amplifier U1, the anode of the first diode D1 is connected to the output end of the first operational amplifier U1 and the cathode of the second diode D2, and the cathode of the first diode D1 is connected to the inverting input end of the first operational amplifier U1 and the first end of the second resistor R2.

[0029] As an optional implementation, in one embodiment of the invention, see Figure 2 As shown, the second operational amplifier unit includes: a seventh resistor R7, an eighth resistor R8, a second operational amplifier U2, and a fifth resistor R5 and a sixth resistor R6 having the same resistance; the resistance of the sixth resistor R6 is twice the resistance of the seventh resistor R7; a first end of the seventh resistor R7 is connected to the anode of the second diode D2, a second end of the seventh resistor R7 is connected to the inverting input terminal of the second operational amplifier U2, a first end of the fifth resistor R5 is connected to the first end of the second resistor, a second end of the fifth resistor R5 is connected to the second end of the seventh resistor R7 and the inverting input terminal of the second operational amplifier U2, a first end of the sixth resistor R6 is connected to the second end of the fifth resistor R5, the second end of the seventh resistor R7, and the inverting input terminal of the second operational amplifier U2, a second end of the sixth resistor R6 is connected to the output terminal of the second operational amplifier U2, the output terminal of the second operational amplifier U2 is connected to the closed-loop control circuit and the overcurrent protection circuit respectively, a first end of the eighth resistor R8 is connected to the non-inverting input terminal of the second operational amplifier U2, and a second end of the eighth resistor R8 is grounded.

[0030] Specifically, see Figure 2 As shown, when the current sampling circuit converts the current of the bidirectional DCDC converter into a positive voltage VR1, the output terminal of the first operational amplifier unit is a negative voltage -V1, then the first diode D1 is cut off and the second diode D2 is turned on. At this time, the voltage at the input terminal V2 of the second operational amplifier unit is , since the resistance of the second resistor is the same as the resistance of the fourth resistor, that is, R2=R4, the voltage of the input terminal V2 of the second operational amplifier unit is , the voltage at the output terminal V3 of the second operational amplifier unit is Since the resistance of the fifth resistor is the same as that of the sixth resistor, and the resistance of the sixth resistor is twice that of the seventh resistor, that is, R5=R6, R6=2R7, the voltage at the output terminal V3 of the second operational amplifier unit is When the current sampling circuit converts the current of the bidirectional DCDC converter into a negative voltage -VR1, the output terminal of the first operational amplifier unit is a positive voltage V1, the first diode D1 is turned on, and the second diode D2 is turned off. At this time, the voltage at the input terminal V2 of the second operational amplifier unit is , the voltage at the output terminal V3 of the second operational amplifier unit is Since the resistance of the fifth resistor is the same as that of the sixth resistor, and the resistance of the sixth resistor is twice that of the seventh resistor, that is, R5=R6, R6=2R7, the voltage at the output terminal V3 of the second operational amplifier unit is Regardless of whether the current sampling circuit outputs a positive voltage or a negative voltage, the first operational amplifier unit and the second operational amplifier unit flip the output to a positive voltage and can simultaneously serve as the input signal of the closed-loop control circuit and the overcurrent protection circuit.

[0031] Furthermore, the models of the first diode D1 and the second diode D2 are both 1N4148, the resistance of the second resistor R2 and the resistance of the fourth resistor R4 are 20KΩ, the resistance of the fifth resistor R5 and the resistance of the sixth resistor R6 are 20KΩ, and the resistance of the seventh resistor R7, the resistance of the third resistor R3, and the resistance of the eighth resistor R8 are all 10KΩ.

[0032] As an optional implementation, in one embodiment of the invention, see Figure 2 As shown, the model of the first operational amplifier and the second operational amplifier is OPA602. OPA602 is a high-performance precision operational amplifier with high-speed response capability, high precision and low offset characteristics. It has a high conversion rate and can quickly respond to signal changes, thereby improving the reaction and processing speed of the circuit.

[0033] An embodiment of the present invention further provides a current detection device for a bidirectional DCDC converter, comprising the aforementioned current detection circuit of the bidirectional DCDC converter. The detection circuit comprises a current sampling circuit and an operational amplifier circuit. The current sampling circuit is connected to the bidirectional DCDC converter and is configured to convert the current of the bidirectional DCDC converter into a positive voltage or a negative voltage based on current sensing. The input end of the operational amplifier circuit is connected to the output end of the current sampling circuit and is configured to convert the positive voltage or negative voltage of the current sampling circuit into a positive voltage and output the converted voltage to a subsequent closed-loop control circuit and an overcurrent protection circuit.

[0034] In a current detection device for a bidirectional DCDC converter according to an embodiment of the present invention, a current detection circuit of the bidirectional DCDC converter includes a current sampling circuit and an operational amplifier circuit. The current sampling circuit is connected to the bidirectional DCDC converter and is used to convert the current of the bidirectional DCDC converter into a positive voltage or a negative voltage based on current sensing. The input end of the operational amplifier circuit is connected to the output end of the current sampling circuit and is used to convert the positive or negative voltage of the current sampling circuit into a positive voltage and output the converted voltage to a subsequent closed-loop control circuit and an overcurrent protection circuit. The present invention uses the current sampling circuit to collect the current of the bidirectional DCDC converter based on current sensing. The current collection response speed is fast and the circuit is suitable for overcurrent protection circuits. At the same time, the positive voltage or negative voltage output by the current sampling circuit is converted into a positive voltage by the operational amplifier circuit. There is no voltage drop and no distortion of the low-voltage portion of the sampling signal. The present invention is also suitable for closed-loop control circuits. The current sampling circuit can collect the current of the bidirectional DCDC converter and simultaneously serve as the input of the closed-loop control circuit and the overcurrent protection circuit through a single current sampling circuit. There is no need to use two different current sampling circuits, namely a Hall detection chip and a current transformer, to collect the current value of the bidirectional DC-DC converter. This simplifies the circuit, improves the circuit collection and processing speed, and reduces the circuit manufacturing cost.

[0035] In the description of the present invention, it should be noted that the orientation or positional relationship indicated by the terms "upper" and "lower" is based on the orientation or positional relationship shown in the accompanying drawings, and is only for the convenience of describing the present invention and simplifying the description, rather than indicating or implying that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation, and therefore cannot be understood as a limitation on the present invention. Unless otherwise clearly specified and limited, the terms "installed", "connected", and "connected" 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 it can be indirectly connected through an intermediate medium, or it can be internal communication between two elements. For those of ordinary skill in the art, the specific meanings of the above terms in the present invention can be understood according to the specific circumstances.

[0036] It should be noted that, in the present invention, relational terms such as "first" and "second" are merely used to distinguish one entity or operation from another entity or operation, and do not necessarily require or imply the existence of any such actual relationship or order between these entities or operations. Moreover, the terms "include", "comprise" or any other variants thereof are intended to cover non-exclusive inclusion, so that a process, method, article or device comprising a series of elements includes not only those elements, but also other elements not explicitly listed, or also includes elements inherent to such process, method, article or device. In the absence of further restrictions, an element defined by the sentence "comprising a ..." does not exclude the presence of other identical elements in the process, method, article or device comprising the element.

[0037] The foregoing description is intended only to provide specific embodiments of the present invention, which will enable those skilled in the art to understand and implement the present invention. Various modifications to these embodiments will be readily apparent to those skilled in the art, and the general principles defined herein may be implemented in other embodiments without departing from the spirit or scope of the present invention. Therefore, the present invention is not intended to be limited to the embodiments shown herein, but is to be construed in the widest possible manner consistent with the principles and novel features of the present invention.

Claims

1. A current detection circuit for a bidirectional DCDC converter, characterized in that: include: Current sampling circuit and operational amplifier circuit; The current sampling circuit is connected to the bidirectional DCDC converter and is used to convert the current of the bidirectional DCDC converter into a positive voltage or a negative voltage according to current sensing; The input end of the operational amplifier circuit is connected to the output end of the current sampling circuit, and is used to convert the positive voltage or negative voltage of the current sampling circuit into a positive voltage and output it to the subsequent closed-loop control circuit and overcurrent protection circuit.

2. The current detection circuit of the bidirectional DCDC converter according to claim 1, wherein: The current sampling circuit includes: A current sensing sensor, the current sensing sensor is connected to the bidirectional DCDC converter, and an output end of the current sensing sensor is connected to the operational amplifier circuit; A sampling resistor, wherein a first end of the sampling resistor is connected to the output end of the current sensing sensor and the input end of the operational amplifier circuit, and a second end of the sampling resistor is grounded.

3. The current detection circuit of the bidirectional DCDC converter according to claim 2, wherein: The current sensing sensor is a Hall effect current sensor or a current transformer.

4. The current detection circuit of the bidirectional DCDC converter according to claim 2, wherein: The sampling resistor is a precision current sampling resistor.

5. The current detection circuit of the bidirectional DCDC converter according to claim 2, wherein: The current sampling circuit further includes: a first capacitor, wherein a first end of the first capacitor is connected to the positive power supply terminal of the current sensing sensor, and a second end of the first capacitor is grounded; A second capacitor, wherein a first end of the second capacitor is connected to the negative power supply end of the current sensing sensor, and a second end of the second capacitor is grounded.

6. The current detection circuit of the bidirectional DCDC converter according to claim 2, wherein: The operational amplifier circuit comprises: a first operational amplifier unit, the first operational amplifier unit being connected to the output end of the current sensing sensor and the first end of the sampling resistor; The second operational amplifier unit is connected to the output end of the first operational amplifier unit and the output end of the current sensing sensor respectively, and is used to convert the positive voltage or negative voltage collected by the sampling resistor into a positive voltage and output it to the closed-loop control circuit and the overcurrent protection circuit.

7. The current detection circuit of the bidirectional DCDC converter according to claim 6, wherein: The first operational amplifier unit includes: a first operational amplifier, a third resistor, a first diode, a second diode, and a second resistor and a fourth resistor of the same resistance value, wherein the first end of the second resistor is connected to the output end of the current sensing sensor and the first end of the sampling resistor, the second end of the second resistor is connected to the inverting input end of the first operational amplifier, the first end of the third resistor is connected to the non-inverting input end of the first operational amplifier, the second end of the third resistor is grounded, the first end of the fourth resistor is connected to the inverting input end of the first operational amplifier, the second end of the fourth resistor is connected to the anode of the second diode, the anode of the second diode is connected to the second operational amplifier unit, the cathode of the second diode is connected to the output end of the first operational amplifier, the anode of the first diode is connected to the output end of the first operational amplifier and the cathode of the second diode, and the cathode of the first diode is connected to the inverting input end of the first operational amplifier and the first end of the second resistor.

8. The current detection circuit of the bidirectional DCDC converter according to claim 7, wherein: The second operational amplifier unit includes: a seventh resistor, an eighth resistor, a second operational amplifier, and a fifth resistor and a sixth resistor having the same resistance; The resistance of the sixth resistor is twice the resistance of the seventh resistor; A first end of the seventh resistor is connected to the anode of the second diode, a second end of the seventh resistor is connected to the inverting input of the second operational amplifier, a first end of the fifth resistor is connected to the first end of the second resistor, a second end of the fifth resistor is connected to the second end of the seventh resistor and the inverting input of the second operational amplifier, a first end of the sixth resistor is connected to the second end of the fifth resistor, the second end of the seventh resistor, and the inverting input of the second operational amplifier, a second end of the sixth resistor is connected to the output of the second operational amplifier, the output of the second operational amplifier is respectively connected to the closed-loop control circuit and the overcurrent protection circuit, a first end of the eighth resistor is connected to the non-inverting input of the second operational amplifier, and a second end of the eighth resistor is grounded.

9. The current detection circuit of the bidirectional DCDC converter according to claim 8, wherein: The models of the first operational amplifier and the second operational amplifier are OPA602.

10. A current detection device for a bidirectional DCDC converter, characterized in that: A current detection circuit comprising the bidirectional DCDC converter according to any one of claims 1 to 9.

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