Bidirectional current detection circuit, chip and electronic device

Abstract

A bidirectional current detection circuit includes: a first power device, the drain of which is connected to the input end of a drain voltage detection module, and the source of which is connected to the second gating end of a first switch and the first gating end of a second switch; the output end of the drain voltage detection module is connected to the first gating end of the first switch and the second gating end of the second switch; the common end of the first switch is connected to the first input end of a transconductance amplifier module; the common end of the second switch is connected to the source of a seventh power device; the seventh power device, the drain of which is connected to the current output end and the second input end of the transconductance amplifier module, and the gate of which is connected to a switch control signal from an external source. The bidirectional current detection circuit of the present invention can detect currents in two different directions, improves the accuracy of bidirectional current detection, and reduces the circuit cost of bidirectional current detection.

Description

Technical Field

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

[0002] With the widespread application of power electronic equipment, there are a lot of situations where current may flow in both directions during the power transmission process, such as electric vehicle power management systems, backup power systems, motor drive systems, etc. In these applications, it is necessary to detect the bidirectional current flowing through the power devices.

[0003] Existing detection methods either only detect unidirectional current, and two sets of detection circuits are needed for bidirectional current detection, or bidirectional current detection requires auxiliary power supply, and the polarity of bidirectional current cannot be handled well, resulting in the need to run two acquisition lines and power supply lines to the operational amplifier during design, which increases the difficulty of wiring, increases the area of ​​PCB (Printed Circuit Board), and increases the energy consumption of electronic equipment and circuit design costs. Summary of the invention

[0004] In order to solve the defects of the prior art, the purpose of the present invention is to provide a bidirectional current detection circuit and electronic equipment, which can detect currents in two different directions by using a set of detection circuits.

[0005] In order to achieve the above object, the present invention provides a bidirectional current detection circuit, comprising:

[0006] A first power device, a drain electrode connected to the input terminal of the drain voltage detection module, and a source electrode connected to the second selection terminal of the first switch and the first selection terminal of the second switch;

[0007] The output end of the drain voltage detection module is connected to the first gating end of the first switch and the second gating end of the second switch;

[0008] The common terminal of the first switch is connected to the first input terminal of the transconductance amplifier module;

[0009] The common terminal of the second switch is connected to the source of the seventh power device;

[0010] The seventh power device has a drain connected to the current output terminal and the second input terminal of the transconductance amplifier module.

[0011] Further, the drain voltage detection module is a direct connection line, one end of which is connected to the drain of the first power device, and the other end is connected to the first gate terminal of the first switch and the second gate terminal of the second switch; or

[0012] The drain voltage detection module includes a second power device and a resistor, wherein:

[0013] The second power device has a gate connected to the gate of the first power device, a drain connected to the drain of the first power device, and a source connected to the first gating end of the first switch, the second gating end of the second switch, and one end of the resistor;

[0014] The other end of the resistor is connected to the source of the first power device.

[0015] Furthermore, the transconductance amplifier module includes an operational amplifier and a third power device, wherein:

[0016] The negative input terminal of the operational amplifier is connected to the common terminal of the first switch;

[0017] The output end of the operational amplifier is connected to the gate of the third power device;

[0018] The positive input terminal of the operational amplifier is connected to the drain of the third power device and the drain of the seventh power device M7.

[0019] Furthermore, it also includes a current switching module, the input end of the current switching module is connected to the voltage output end of the transconductance amplifier module.

[0020] Furthermore, the current switching module includes: a fourth power device, a second current mirror, and a third switch, wherein:

[0021] The gate of the fourth power device is connected to the voltage output terminal of the transconductance amplifier module, the drain is connected to the common terminal of the third switch, and the source is connected to the power supply;

[0022] The second current mirror comprises: a fifth power device and a sixth power device, wherein:

[0023] The drain and gate of the fifth power device and the gate of the sixth power device are connected to the second gate terminal of the third switch;

[0024] The source of the fifth power device and the source of the sixth power device are grounded;

[0025] The drain of the sixth power device is connected to the first selection end of the third switch as the second current output end of the circuit.

[0026] Furthermore, the third power device and the fourth power device form a first current mirror.

[0027] Further, when the measured current is a forward current, the first switch and the second switch are configured as follows: the common end of the first switch is closed to the first selection end thereof, so that the output of the drain voltage detection module is connected to the reverse input end of the remote amplifier; the common end of the second switch is closed to the first selection end thereof, so that the source of the seventh power device is connected to the source of the first power device;

[0028] When the measured current is a reverse current, the first switch and the second switch are configured as follows: the common end of the first switch and its second selection end are closed, so that the reverse input end of the operational amplifier is connected to the source of the first power device; the common end of the second switch and its second selection end are closed, so that the source of the seventh power device is connected to the output of the drain voltage detection module.

[0029] Furthermore, when the measured current is a forward current, the third switch is configured as follows: the common terminal of the third switch is closed with its first selection terminal, so that the drain of the fourth power device is connected to the drain of the sixth power device;

[0030] When the measured current is a reverse current, the third switch is configured such that: the common terminal of the third switch and the second selection terminal thereof are closed, so that the drain of the fourth power device is connected to the drain of the fifth power device.

[0031] On the other hand, a bidirectional current detection chip is also provided, comprising the bidirectional current detection circuit as described above.

[0032] On the other hand, an electronic device is also provided, comprising the bidirectional current detection chip as described above.

[0033] The bidirectional current detection circuit provided by the present invention has the following beneficial effects compared with the prior art:

[0034] The switch provides a voltage switching mode through two switches, and can detect currents in two different directions, thereby ensuring that the measurement accuracy of current detection in the two directions is consistent, improving the accuracy of bidirectional current detection, and reducing the circuit cost of bidirectional current detection.

[0035] Other features and advantages of the present invention will be set forth in the description which follows, and in part will be apparent from the description, or may be learned by practice of the present invention. BRIEF DESCRIPTION OF THE DRAWINGS

[0036] The accompanying drawings are used to provide a further understanding of the present invention and constitute a part of the specification. Together with the embodiments of the present invention, they are used to explain the present invention and do not constitute a limitation of the present invention. In the accompanying drawings:

[0037] Figure 1A schematic diagram of the structure of a bidirectional current detection circuit according to an embodiment of the present invention;

[0038] Figure 2 A schematic diagram of a bidirectional current detection circuit according to an embodiment of the present invention;

[0039] Figure 3 A schematic diagram of forward current detection of a bidirectional current detection circuit according to an embodiment of the present invention;

[0040] Figure 4 A schematic diagram of reverse current detection of a bidirectional current detection circuit according to an embodiment of the present invention;

[0041] Figure 5 4 is a timing diagram of the switch and output current changing with the power device current according to an embodiment of the present invention. DETAILED DESCRIPTION

[0042] The preferred embodiments of the present invention are described below in conjunction with the accompanying drawings. It should be understood that the preferred embodiments described herein are only used to illustrate and explain the present invention, and are not used to limit the present invention.

[0043] Embodiments of the present invention will be described in more detail below with reference to the accompanying drawings. Although certain embodiments of the present invention are shown in the accompanying drawings, it should be understood that the present invention can be implemented in various forms and should not be construed as being limited to the embodiments described herein, which are instead provided for a more thorough and complete understanding of the present invention. It should be understood that the drawings and embodiments of the present invention are only for exemplary purposes and are not intended to limit the scope of protection of the present invention.

[0044] The term "including" and its variations used herein are open inclusions, i.e., "including but not limited to". The term "based on" means "based at least in part on". The term "one embodiment" means "at least one embodiment"; the term "another embodiment" means "at least one additional embodiment"; the term "some embodiments" means "at least some embodiments". The relevant definitions of other terms will be given in the following description.

[0045] It should be noted that the concepts of “first”, “second”, etc. may be mentioned in the present invention only to distinguish different devices, components or parts, and are not used to limit the order or interdependence of the functions performed by these devices, components or parts.

[0046] It should be noted that the modifications of "one" and "plurality" mentioned in the present invention are illustrative rather than restrictive, and those skilled in the art should understand that unless otherwise clearly indicated in the context, it should be understood as "one or more". "Plurality" should be understood as two or more.

[0047] In the present invention, the power device MOSFET (Metal-Oxide-Semiconductor Field-EffectTransistor) includes a first terminal, a second terminal and a control terminal. When the MOSFET is in the on state, the current flows from the first terminal to the second terminal. The first terminal, the second terminal and the control terminal of the P-type MOSFET (hereinafter referred to as PMOS) are respectively the source, the drain and the gate, and the first terminal, the second terminal and the control terminal of the N-type MOSFET (hereinafter referred to as NMOS) are respectively the drain, the source and the gate.

[0048] It should be noted that, although in this article, the power device is described as a certain NMOS or PMOS device, it can be understood by those skilled in the art that complementary devices can also be implemented according to the present invention. It can be understood by those skilled in the art that the conductivity type refers to the mechanism by which the conduction occurs, such as conduction by holes or electrons, and therefore the conductivity type does not involve the doping concentration but the doping type, such as P-type or N-type.

[0049] The bidirectional current detection circuit of the embodiment of the present invention includes: a first power device, the drain of which is connected to the first enable terminal of the first switch, the second enable terminal of the second switch, and the first current output terminal; the second enable terminal of the first switch and the first enable terminal of the second switch are connected to the source level of the first power device; the common terminal of the first switch is connected to the first input terminal of the transconductance amplifier module; the common terminal of the second switch is connected to the source terminal of the seventh power device; the drain terminal of the seventh power device is connected to the current output terminal and the second input terminal of the transconductance amplifier module; the voltage output terminal of the transconductance amplifier module is connected to the input terminal of the current switching module.

[0050] In order to make the objectives, technical solutions and advantages of the present invention more clear, the embodiments of the present invention will be further described in detail below with reference to the accompanying drawings.

[0051] Example 1

[0052] Figure 1 FIG. 1 is a schematic diagram of a bidirectional current detection circuit according to an embodiment of the present invention. Figure 1 As shown, the bidirectional current detection circuit of this embodiment includes: a first power device M1, a drain voltage detection module 103, a first switch S1, a second switch S2, a transconductance amplifier unit 101, a seventh power device M7, and a current switching module 102, wherein:

[0053] The drain of the first power device M1 is connected to the first current input and output terminal I out , an input terminal of the drain voltage detection module 103;

[0054] The output end of the drain voltage detection module 103 is connected to the switch S 1 The first selection terminal, switch S 2 A second strobe terminal;

[0055] The source of the first power device M1, the switch S 1 The second selection terminal of the switch S 2 The first gate terminal is grounded;

[0056] The gate of the first power device M1 and the gate of the seventh power device M7 are connected to the external switch control signal V drv ;

[0057] Switch S 1 The common end is connected to the first input terminal V of the transconductance amplifier unit 101. in1 ;

[0058] Switch S 2 A common end is connected to the source of the seventh power device M7;

[0059] The second input terminal V of the transconductance amplifier unit 101 in2 and the current output terminal I out1 are connected to each other, and connected to the drain of the seventh power device M7;

[0060] The voltage output terminal V of the transconductance amplifier unit 101 o connected to the input end of the current switching module 102;

[0061] The output terminal of the current switching module 102 is the second current input and output terminal of the circuit.

[0062] In an exemplary embodiment, the drain voltage detection module 103 is a direct line, one end of which is connected to the drain of the first power device M1, and the other end of which is connected to the switch S 1 The first selection terminal, switch S 2 is connected to the second select terminal of.

[0063] In this embodiment, the switch S 1 , S 2 It is a single-pole double-throw switch.

[0064] Example 2

[0065] Figure 2 Schematic diagram of the principle of a bidirectional current detection circuit according to an embodiment of the present invention. Figure 2As shown, the drain of the first power device M1 is connected to the drain of the second power device M2, the gate of the first power device M1 is connected to the gate of the second power device M2, the source of the second power device M2 is connected to one end of the resistor R1, and the other end of the resistor R1 and the source of the first power device M1 are both grounded. 1 The first gate terminal of the switch S is connected to the source of the second power device M2. 1 The second gate terminal of the switch S is grounded. 1 The common terminal is connected to the inverting input terminal of the operational amplifier Amp.

[0066] The second power device M2 and the resistor R1 constitute the drain voltage detection module 103 of the present invention.

[0067] The gate of the third power device M3 is connected to the output terminal of the operational amplifier Amp, the drain of the third power device M3 and the drain of the seventh power device M7 are connected to the positive input terminal of the operational amplifier Amp, and the source of the seventh power device M7 is connected to the switch S 2 The common terminal of switch S 2 The first gate terminal of the switch S is grounded. 2 The second gate terminal is connected to the source of the second power device M2.

[0068] The source of the fourth power device M4 is connected to the source of the third power device M3, the gate of the fourth power device M4 is connected to the output terminal of the operational amplifier Amp, and the drain of the fourth power device M4 is connected to the switch S 3 The common terminal of switch S 3 The first gate terminal of the switch S is connected to the drain of the sixth power device M6. 3 The second gate end of the fifth power device M5 is respectively connected to the drain of the fifth power device M5, the gate of the fifth power device M5 and the gate of the sixth power device M6. The source of the fifth power device M5 and the source of the sixth power device M6 are both grounded.

[0069] In the embodiment of the present invention, the operational amplifier Amp and the third power device M3 constitute the transconductance amplifier module 101 of the present invention.

[0070] Switch S 3 It is a single-pole double-throw switch.

[0071] In the embodiment of the present invention, the fourth power device M4, the fifth power device M5 and the sixth power device M6 of the second current mirror, and the switch S3 constitute the current switching module 102 of the present invention.

[0072] In the embodiment of the present invention, the first power device M1, the second power device M2 and the seventh power device M7 are all NMOS, the third power device M3 and the fourth power device M4 are all PMOS, and the fifth power device M5 and the sixth power device M6 are also NMOS.

[0073] In an exemplary embodiment, the gates of the first power device M1 and the second power device M2 are connected together to receive an external switch control signal V drv The gate of the seventh power device M7 also receives the control signal V drv .

[0074] In an exemplary embodiment, sources of the third power device M3 and the fourth power device M4 are connected to each other to access the same operating voltage VDD.

[0075] In an exemplary embodiment, the resistance of R1 is much greater than the resistance of M2. M1 , so the detection node V at the source end of M2 S The voltage is approximately equal to the node V at the drain end of M2 D Voltage, V D The voltage is equal to the voltage drop V of M1 DS , V S The voltage is approximately equal to M1's V DS M7 is a mirror device of M1, that is, M7 and M1 are devices of the same type, and the resistance ratio of M7 to M1 is K. M3 and M4 form the first current mirror, and the amplification ratio is N. M5 and M6 form the second current mirror, and the amplification ratio is 1. out is the first output current, and the positive direction of the current is node V D to GND, I sout is the second output current, and the positive direction of the current is node V 6 outflow.

[0076] It should be noted that, in the above exemplary embodiments, the seventh power device M7 is a mirror device of the first power device M1, that is, the two are power devices of the same conductive type. A person skilled in the art can understand that in some other embodiments of the present invention, a resistor can be selected to replace the seventh power device M7 as a mirror device of the first power device M1.

[0077] The bidirectional current detection principle of the bidirectional current detection circuit according to the embodiment of the present invention is further described in detail below in conjunction with the accompanying drawings. Figure 3 FIG. 1 is a schematic diagram of a forward current detection circuit according to an embodiment of the present invention. Figure 3 The forward current detection principle of the bidirectional current detection circuit according to the embodiment of the present invention is described.

[0078] like Figure 3 As shown, when I out When the direction is positive, switch S 1 The first selection terminal is closed to its common terminal, so that the inverting input terminal of the operational amplifier Amp is connected to the source of M2; the switch S 2 The first selection terminal of the switch S is closed to its common terminal, so that the source of M7 is grounded; 3 The first gate terminal of is closed to its common terminal, so that the drain of M4 is connected to the drain of M6. That is, node V S The voltage is I out ×R M1 , the node V at the inverting input of the operational amplifier Amp A1 Connect to V S , the node V at the source end of M7 R Connect to GND, node V at the drain end of M4 4 Connect to V 6 Due to the amplification of the operational amplifier Amp, the node V A2 The voltage is equal to V S , so node V 6 Outflow current I sout For I out ×N / K.

[0079] Figure 4 FIG. 1 is a schematic diagram of reverse current detection of a bidirectional current detection circuit according to an embodiment of the present invention. Figure 4 The reverse current detection principle of the bidirectional current detection circuit according to the embodiment of the present invention is described.

[0080] like Figure 4 As shown, when I out When the direction is negative, switch S 1 The second selection terminal is closed to its common terminal, so that the inverting input terminal of the operational amplifier Amp is grounded; the switch S 2 The second selection terminal of the switch S is closed to its common terminal, so that the source of M7 is connected to the source of M2; 3 The second gate terminal of is closed to its common terminal, so that the drain of M4 is connected to the drain of M5, the control terminal of M5 and the control terminal of M6. That is, V S The voltage is -I out ×R M1 Less than 0V (GND), V A1 Connect to GND, V R Connect to V S , V 4 Connect to the node V at the drain end of M5 5 , due to the amplification of the operational amplifier Amp, V A2The voltage at node V 6 Outflow current I sout For-I out ×N / K.

[0081] Figure 5 is a timing diagram of the switch and output current changing with the power device current according to an embodiment of the present invention, such as Figure 5 As shown, correspondingly, at the same time, that is, when current detection in one direction is performed, the switch S 1 , S 2 , S 3 The first strobe terminal S 1-1 , S 2-1 , S 3-1 Close (first strobe terminal S 1-1 , S 2-1 , S 3-1 are connected to the corresponding common terminals respectively) to detect the current in the other direction. 1 , S 2 , S 3 The second strobe terminal S 1-2 , S 2-2 , S 3-2 Close (first strobe terminal S 1-1 , S 2-1 , S 3-1 Disconnect from the corresponding common terminal respectively, S 1-2 , S 2-2 , S 3-2 are connected to the corresponding common terminals respectively).

[0082] The bidirectional current detection circuit provided in the embodiment of the present invention adopts a switch S 1 , S 2 The loop composed of Amp, M3, and M7 provides two voltage switching modes. The first current mirror (M3, M4), the second current mirror (M5, M6), and the switch S 3 By forming an output circuit, current detection in two different directions can be completed. The bidirectional current detection circuit ensures that the measurement accuracy of current detection in two directions is consistent, improves the accuracy of bidirectional current detection, and at the same time, reduces the circuit cost.

[0083] Example 3

[0084] In an embodiment of the present invention, a bidirectional current detection chip is further provided. The bidirectional current detection chip includes the bidirectional current detection circuit of the above embodiment.

[0085] Example 4

[0086] In an embodiment of the present invention, an electronic device is also provided, including the bidirectional current detection circuit of the above embodiment. The electronic device using this bidirectional current detection circuit can detect bidirectional current, and the output current can be in both positive and negative directions, which greatly reduces the circuit cost of bidirectional current detection in the electronic device and ensures the consistency of current detection accuracy in both directions.

[0087] Those skilled in the art can understand that the above description is only a preferred embodiment of the present invention and is not intended to limit the present invention. Although the present invention is described in detail with reference to the aforementioned embodiments, those skilled in the art can still modify the technical solutions recorded in the aforementioned embodiments or replace some of the technical features therein by equivalents. Any modification, equivalent replacement, improvement, etc. made within the spirit and principle of the present invention shall be included in the protection scope of the present invention.

Claims

1. A bidirectional current detection circuit, characterized in that: include: A first power device, a drain electrode connected to the input terminal of the drain voltage detection module, and a source electrode connected to the second selection terminal of the first switch and the first selection terminal of the second switch; The output end of the drain voltage detection module is connected to the first gating end of the first switch and the second gating end of the second switch; The common terminal of the first switch is connected to the first input terminal of the transconductance amplifier module; The common terminal of the second switch is connected to the source of the seventh power device; The seventh power device has a drain connected to the current output terminal and the second input terminal of the transconductance amplifier module; The drain voltage detection module is a direct connection line, one end of which is connected to the drain of the first power device, and the other end is connected to the first gate terminal of the first switch and the second gate terminal of the second switch; or The drain voltage detection module includes a second power device and a resistor, wherein: The second power device has a gate connected to the gate of the first power device, a drain connected to the drain of the first power device, and a source connected to the first gating end of the first switch, the second gating end of the second switch, and one end of the resistor; The other end of the resistor is connected to the source of the first power device.

2. The bidirectional current detection circuit according to claim 1, characterized in that: The transconductance amplifier module includes an operational amplifier and a third power device, wherein: The negative input terminal of the operational amplifier is connected to the common terminal of the first switch; The output end of the operational amplifier is connected to the gate of the third power device; The positive input terminal of the operational amplifier is connected to the drain of the third power device and the drain of the seventh power device M7.

3. The bidirectional current detection circuit according to claim 2, characterized in that: It also includes a current switching module, the input end of which is connected to the voltage output end of the transconductance amplifier module.

4. The bidirectional current detection circuit according to claim 3, characterized in that: The current switching module includes: a fourth power device, a second current mirror, and a third switch, wherein: The gate of the fourth power device is connected to the voltage output terminal of the transconductance amplifier module, the drain is connected to the common terminal of the third switch, and the source is connected to the power supply; The second current mirror comprises: a fifth power device and a sixth power device, wherein: The drain and gate of the fifth power device and the gate of the sixth power device are connected to the second gate terminal of the third switch; The source of the fifth power device and the source of the sixth power device are grounded; The drain of the sixth power device is connected to the first selection end of the third switch as the second current output end of the circuit.

5. The bidirectional current detection circuit according to claim 4, characterized in that: The third power device and the fourth power device form a first current mirror.

6. The bidirectional current detection circuit according to claim 4, characterized in that: When the measured current is a forward current, the first switch and the second switch are configured as follows: the common end of the first switch and its first selection end are closed, so that the output of the drain voltage detection module is connected to the reverse input end of the operational amplifier; the common end of the second switch and its first selection end are closed, so that the source of the seventh power device is connected to the source of the first power device; When the measured current is a reverse current, the first switch and the second switch are configured as follows: the common end of the first switch and its second selection end are closed, so that the reverse input end of the operational amplifier is connected to the source of the first power device; the common end of the second switch and its second selection end are closed, so that the source of the seventh power device is connected to the output of the drain voltage detection module.

7. The bidirectional current detection circuit according to claim 4, characterized in that: When the measured current is a forward current, the third switch is configured as follows: the common terminal of the third switch and its first selection terminal are closed, so that the drain of the fourth power device is connected to the drain of the sixth power device; When the measured current is a reverse current, the third switch is configured such that: the common terminal of the third switch and the second selection terminal thereof are closed, so that the drain of the fourth power device is connected to the drain of the fifth power device.

8. A bidirectional current detection chip, characterized in that: A bidirectional current detection circuit comprising any one of claims 1 to 7.

9. An electronic device, characterized in that: Includes the bidirectional current detection chip as described in claim 8.

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