CN112014623A - Current sampling circuit and power supply converter - Google Patents

Current sampling circuit and power supply converter Download PDF

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Publication number
CN112014623A
CN112014623A CN202010905446.4A CN202010905446A CN112014623A CN 112014623 A CN112014623 A CN 112014623A CN 202010905446 A CN202010905446 A CN 202010905446A CN 112014623 A CN112014623 A CN 112014623A
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current
circuit
sampling
resistor
load
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CN112014623B (en
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余东升
刘珍超
李念龙
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Shanghai Awinic Technology Co Ltd
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Shanghai Awinic Technology Co Ltd
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    • G—PHYSICS
    • G01—MEASURING; TESTING
    • G01R—MEASURING ELECTRIC VARIABLES; MEASURING MAGNETIC VARIABLES
    • G01R19/00—Arrangements for measuring currents or voltages or for indicating presence or sign thereof
    • G01R19/0092—Arrangements for measuring currents or voltages or for indicating presence or sign thereof measuring current only
    • H—ELECTRICITY
    • H02—GENERATION; CONVERSION OR DISTRIBUTION OF ELECTRIC POWER
    • H02M—APPARATUS FOR CONVERSION BETWEEN AC AND AC, BETWEEN AC AND DC, OR BETWEEN DC AND DC, AND FOR USE WITH MAINS OR SIMILAR POWER SUPPLY SYSTEMS; CONVERSION OF DC OR AC INPUT POWER INTO SURGE OUTPUT POWER; CONTROL OR REGULATION THEREOF
    • H02M3/00—Conversion of dc power input into dc power output
    • H02M3/02—Conversion of dc power input into dc power output without intermediate conversion into ac
    • H02M3/04—Conversion of dc power input into dc power output without intermediate conversion into ac by static converters
    • H02M3/10—Conversion of dc power input into dc power output without intermediate conversion into ac by static converters using discharge tubes with control electrode or semiconductor devices with control electrode
    • H02M3/145—Conversion of dc power input into dc power output without intermediate conversion into ac by static converters using discharge tubes with control electrode or semiconductor devices with control electrode using devices of a triode or transistor type requiring continuous application of a control signal
    • H02M3/155—Conversion of dc power input into dc power output without intermediate conversion into ac by static converters using discharge tubes with control electrode or semiconductor devices with control electrode using devices of a triode or transistor type requiring continuous application of a control signal using semiconductor devices only
    • H02M3/156—Conversion of dc power input into dc power output without intermediate conversion into ac by static converters using discharge tubes with control electrode or semiconductor devices with control electrode using devices of a triode or transistor type requiring continuous application of a control signal using semiconductor devices only with automatic control of output voltage or current, e.g. switching regulators
    • H02M3/158—Conversion of dc power input into dc power output without intermediate conversion into ac by static converters using discharge tubes with control electrode or semiconductor devices with control electrode using devices of a triode or transistor type requiring continuous application of a control signal using semiconductor devices only with automatic control of output voltage or current, e.g. switching regulators including plural semiconductor devices as final control devices for a single load
    • H02M3/1584—Conversion of dc power input into dc power output without intermediate conversion into ac by static converters using discharge tubes with control electrode or semiconductor devices with control electrode using devices of a triode or transistor type requiring continuous application of a control signal using semiconductor devices only with automatic control of output voltage or current, e.g. switching regulators including plural semiconductor devices as final control devices for a single load with a plurality of power processing stages connected in parallel
    • Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
    • Y02—TECHNOLOGIES OR APPLICATIONS FOR MITIGATION OR ADAPTATION AGAINST CLIMATE CHANGE
    • Y02B—CLIMATE CHANGE MITIGATION TECHNOLOGIES RELATED TO BUILDINGS, e.g. HOUSING, HOUSE APPLIANCES OR RELATED END-USER APPLICATIONS
    • Y02B70/00—Technologies for an efficient end-user side electric power management and consumption
    • Y02B70/10—Technologies improving the efficiency by using switched-mode power supplies [SMPS], i.e. efficient power electronics conversion e.g. power factor correction or reduction of losses in power supplies or efficient standby modes

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  • Physics & Mathematics (AREA)
  • General Physics & Mathematics (AREA)
  • Engineering & Computer Science (AREA)
  • Power Engineering (AREA)
  • Control Of Electrical Variables (AREA)

Abstract

A current sampling circuit and power supply converter, the circuit comprising: the device comprises a mirror current source, a current regulating circuit and a voltage sampling branch circuit; one output branch of the mirror current source is connected with the current regulating circuit, the output current of the mirror current source is changed along with the change of the input current of the load through the current regulating circuit, and the mirror current source has the characteristic of the output voltage of the two output branches, so that the voltage division detection is only needed to be carried out on the other output branch of the mirror current source, the resistance of the voltage sampling branch on the other output branch can be set at will without influencing the input current of the load, and therefore, the resistance value of the voltage sampling branch can be set to be larger during sampling, and the accurate detection of the input current of the load is realized.

Description

Current sampling circuit and power supply converter
Technical Field
The invention relates to the technical field of integrated circuits, in particular to a current sampling circuit and a power supply converter.
Background
Power supply products are widely used in various electronic devices to convert power from one form to another, for example, to convert ac power collected from a power grid into dc power.
The power supply converter is one of basic components of a power supply product, and consists of a power stage circuit and a control loop. The control loop keeps the output voltage or the output current of the power converter stable by adjusting the on-off time of a switching tube and a rectifying tube in the power level circuit when the input voltage and the external load change. When output voltage and current are controlled, the basic reference parameter is load current, therefore, in the control process, whether accurate sampling can be carried out on the load current is very important, the current sampling technology is mainly used for testing the voltage difference between two ends of a sampling resistor, the sampling resistor can be the conduction resistor of a power tube or a separated high-precision resistor, and the separated high-precision resistor is usually selected as the sampling resistor on occasions with high precision requirements due to the fact that the conduction resistor of the power tube fluctuates greatly. In order to reduce the power consumption generated on the sampling resistor, the resistance value is generally small, for example, 20 milliohms, and therefore, the voltage difference between two ends of the sampling resistor is also small, so that a high-precision amplifier needs to be designed inside a chip to improve the sampling precision.
The existing current sampling circuit usually adopts an operational amplifier to amplify a sampling signal, and the circuit design is more complex.
Disclosure of Invention
In view of this, embodiments of the present invention provide a current sampling circuit and a power supply converter to reduce the complexity of circuit design.
In order to achieve the above purpose, the embodiments of the present invention provide the following technical solutions:
a current sampling circuit, comprising:
the device comprises a mirror current source, a current regulating circuit and a voltage sampling branch circuit;
the first output end of the mirror current source is connected with a current source interface of the current regulating circuit, the second output end of the mirror current source is grounded through the voltage sampling branch, and the common end of the mirror current source and the voltage sampling branch is used as the output end of the current sampling circuit;
the output end of the current regulating circuit is connected with a load, and the current regulating circuit is used for controlling the output current of the mirror current source to change along with the change of the current input to the load.
Optionally, in the current sampling circuit, the current adjusting circuit includes: the device comprises a current sampling branch and a load power supply branch;
the current sampling branch circuit comprises a first direct current source, a first resistor and a second resistor which are sequentially connected in series, wherein one end, which is not connected with the first resistor, of the second resistor is connected with the input end of the load, and one end, which is connected with the first resistor, of the second resistor is used for acquiring a target voltage signal output by a target voltage signal source;
the load power supply branch comprises a second direct current source and a third resistor which are sequentially connected in series, the input end of the second direct current source is connected with the input end of the first direct current source, and the end, which is not connected with the second direct current source, of the third resistor is connected with the input end of the load;
and the first output end of the mirror current source is connected with the common end of the second direct current source and the third resistor.
Optionally, in the current sampling circuit, the voltage sampling branch includes:
and the first end of the fourth resistor is connected with the second output end of the mirror current source, the second end of the fourth resistor is grounded, and the first end of the fourth resistor is used as the output end of the current sampling circuit.
Optionally, the current sampling circuit further includes:
and the first synchronous switches are arranged in the current sampling branch and the load power supply branch and are used for controlling the current sampling branch and the load power supply branch to be conducted when current flows through the load power supply branch. 5. The current sampling circuit of claim 4, wherein the first synchronous switch comprises:
the device comprises a first sampling MOS tube and a first load MOS tube;
the first sampling MOS tube is arranged between the first direct current source and the first resistor;
the first load MOS tube is arranged between the second direct current source and the third resistor, and the control end and the input end of the first load MOS tube are connected;
and the control ends of the first sampling MOS tube and the first load MOS tube are interconnected.
Optionally, in the current sampling circuit, the current adjusting circuit 200 includes N current sampling branches, the N current sampling branches are connected in parallel, N is a positive integer not less than 2, and second resistors in different current sampling branches are used to obtain target voltage signals output by different target voltage signal sources;
the current sampling circuit further includes: a mirror current selection switch;
the mirror current selection switch comprises N selection switch MOS tubes in one-to-one correspondence with the N current sampling branches, the input end of each selection switch MOS tube is connected with the first output end of the mirror current source, the output end of each selection switch MOS tube is connected with one end of the third resistor, which is not connected with the load, and the control end of each selection switch MOS tube is connected with the output end of the first current source in the corresponding current sampling branch.
Optionally, the current sampling circuit further includes:
and the second synchronous switches are arranged in the current sampling branch and the load power supply branch and are used for controlling the conduction of the N current sampling branches and the load power supply branch when current flows through the load power supply branch.
Optionally, in the current sampling circuit, the second synchronous switch includes:
the current sampling circuit comprises N second sampling MOS tubes and a second load MOS tube, wherein each current sampling branch is internally provided with one second sampling MOS tube;
each second sampling MOS tube is arranged between a second direct current source and a first resistor in the corresponding current sampling branch;
the second load MOS tube is arranged between the second direct current source and the third resistor, and the control end and the input end of the second load MOS tube are connected;
and the N second sampling MOS tubes are interconnected with the control ends of the second load MOS tubes.
Optionally, in the current sampling circuit, the target voltage signal source is a dc output circuit in a power supply converter that supplies power to the load.
A power converter, comprising: the current sampling circuit of any of the above.
Optionally, the power converter includes a dc output circuit, and the dc output circuit is configured to provide a target voltage signal as the target voltage signal source.
Optionally, in the power supply converter, the current sampling branches correspond to the dc output circuits one to one, and one end of the second resistor in the current sampling branch, which is not connected to the load, is connected to the output end of the dc output circuit corresponding to the second resistor, and the dc output circuit serves as the target voltage signal source to provide the target voltage signal to the current sampling branch corresponding to the target voltage signal source.
Optionally, the power converter further includes:
and the output current modulation module is used for outputting a current modulation signal to a direct current output circuit in the power supply converter based on a comparison result of the voltage signal of the output end of the current sampling circuit and a preset voltage signal, so that the output current of the direct current output circuit changes along with the change of the current modulation signal.
Based on the technical solution, in the solution provided by the embodiment of the present invention, when the current sampling circuit is used to collect the input current of the load, one output branch of the mirror current source is connected to the current regulating circuit, the output current of the mirror current source is changed along with the input current of the load through the current regulating circuit, because the mirror current source has the characteristic of the output voltage of the two output branches, only the other output branch of the mirror current source needs to be subjected to voltage division detection, and the resistance of the voltage sampling branch on the other output branch can be set arbitrarily, the load input current is not influenced, so that the resistance value of the voltage sampling branch circuit can be set to be larger during sampling, and accurate detection of the load input current is realized.
Drawings
In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the drawings used in the description of the embodiments or the prior art will be briefly described below, it is obvious that the drawings in the following description are only embodiments of the present invention, and for those skilled in the art, other drawings can be obtained according to the provided drawings without creative efforts.
Fig. 1 is a schematic structural diagram of a current sampling circuit according to an embodiment of the present disclosure;
fig. 2 is a schematic structural diagram of a current sampling circuit according to another embodiment of the present disclosure;
fig. 3 is a schematic structural diagram of a current sampling circuit according to another embodiment of the present application;
fig. 4 is a schematic structural diagram of a current sampling circuit according to another embodiment of the present application;
fig. 5 is a schematic structural diagram of a power supply converter disclosed in an embodiment of the present application.
Detailed Description
The technical solutions in the embodiments of the present invention will be clearly and completely described below with reference to the drawings in the embodiments of the present invention, and it is obvious that the described embodiments are only a part of the embodiments of the present invention, and not all of the embodiments. All other embodiments, which can be derived by a person skilled in the art from the embodiments given herein without making any creative effort, shall fall within the protection scope of the present invention.
The current sampling circuit is simple in circuit design and does not need to adopt an operational amplifier to amplify a sampling signal, so that accurate measurement of a sampling result can be realized, and the problem of complex circuit design is solved.
Referring to fig. 1, fig. 1 is a current sampling circuit provided in an embodiment of the present application, and includes:
a mirror current source 100, a current regulating circuit 200 and a voltage sampling branch 300;
a first output end of the mirror current source 100 is connected to a current source interface of the current regulating circuit 200, a second output end of the mirror current source 100 is grounded through the voltage sampling branch 300, a common end of the mirror current source 100 and the voltage sampling branch 300 serves as an output end of the current sampling circuit, a structure of the mirror current source 100 can be selected by a user according to a user requirement, and the mirror current source 100 with any structure in the prior art can be selected as the mirror current source 100 disclosed in the embodiment of the present application;
the output terminal of the current regulating circuit 200 and the load R7In connection, the current adjusting circuit 200 is used to control the output current of the mirror current source 100 to follow the change of the current input to the load.
In the above solution, based on the characteristic that the output currents of the two output terminals of the mirror current source 100 are equal, one output branch of the mirror current source 100 is connected to the current adjusting circuit 200, which may be referred to as a first output terminal, and the other output branch of the mirror current source 100 is referred to as a second output terminal, and the output currents of the first output terminal and the second output terminal are equal, the current adjusting circuit 200 controls the output current of the first output terminal of the mirror current source 100 to change along with the change of the current input to the load by connecting the current source interface of the first output terminal to the current adjusting circuit 200, so that the output current of the second output terminal changes along with the change of the current of the load, and the output current of the second output terminal can be detected by detecting the voltage values at the two ends of the voltage sampling branch 300, since the output current of the second output terminal varies with the variation of the current of the load, the reverse derivation may be able to calculate the current input to the load according to the voltage values at the two ends of the voltage sampling branch 300.
Therefore, only the second output terminal of the mirror current source 100 needs to be subjected to voltage division detection, and the resistance of the voltage sampling branch 300 at the second output terminal can be arbitrarily set, which does not affect the load input current, so that the resistance of the voltage sampling branch 300 can be set to be larger during sampling, thereby realizing accurate detection of the load input current.
In the technical solution disclosed in the embodiment of the present application, a specific structure of the modulation circuit may be set according to a user's requirement, as long as it is ensured that the modulation circuit can control the first output terminal of the mirror current source 100 to change along with a change of the current input to the load, for example, referring to fig. 2, in the technical solution disclosed in the embodiment of the present application, the modulation circuit may include a current sampling branch 201 and a load power supply branch 202;
the current sampling branch 201 comprises a first direct current source DC1 and a first resistor R which are sequentially connected in series4And a second resistor R1The output current of the first direct current source DC1 is I1Said second resistance R1Is not connected with the first resistor R4One end of the second resistor R is connected with the input end of the load, and the other end of the second resistor R is connected with the input end of the load1And the first resistor R4The connected end is used for acquiring a target voltage signal output by a target voltage signal source, and the target voltage signal source is an external direct current output power supply relative to the current sampling circuit provided by the application;
a load power supply branch 202, wherein the load power supply branch 202 comprises a second direct current source DC2 and a third resistor R which are sequentially connected in series3An input terminal of the second DC source DC2 is connected with an input terminal of the first DC source DC1, and the third resistor R3In the technical solution disclosed in the embodiment of the present application, the end not connected to the second DC source DC2 is connected to the input end of the load, and the specifications of the second DC source DC2 and the first DC source DC1 may be the same, that is, the output current of the second DC source DC2 is also I1Said third resistance R3And the first resistor R4Can be the same type of resistors with the same resistance value;
the first output terminal of the mirror current source 100 is connected to the current source interface of the current adjusting circuit 200, which is embodied as:
the first output terminal of the mirror current source 100 is connected to the common terminal of the second DC source DC2 and the third resistor R3, and at this time, the common terminal of the second DC source DC2 and the third resistor R3 serves as a current source interface of the current regulating circuit 200.
In the above circuit, the second resistor R1Can be a high-precision sampling resistor, and the port A is connected with the first resistor R4And a second resistor R1A connected port for obtaining a target voltage signal source, wherein the port A is a circuit node with current driving capability, and the target voltage signal source is connected from the port A to a third resistor R3And a first resistor R4The port C in the figure is connected to the common terminal of the mirror current source and voltage sampling branch 300, and the port C serves as the output terminal of the current sampling circuit. The working principle of the current sampling circuit and the derivation of the related formula will be explained in detail below:
in the above circuit, V1Representing the input voltage, V, of the load2Is applied to the second resistance R1Voltage of1Is the output current of the first DC power supply and the second DC power supply, I2Is the output current of the first output terminal of the mirror current source 100.
In the above circuit, the following parameter relationships are provided:
V1+(I1+I2)*R3＝V2+I1*R4said R is3Is said third resistor R3Resistance value of (1), said R4Is the first resistor R4The resistance value of (1);
since R is at design time3＝R4Therefore, the following is obtained:
I2*R3＝V2-V1
V7＝I2*R6＝(V2-V1)*R6/R3said V is7The voltage applied to the voltage sampling branch 300;
in the current sampling circuit in the design, the port C is used as the signal output end of the current sampling circuit, the voltage signal output by the current sampling circuit is used for representing the load current signal, the load current signal is transmitted to the next module through the port C of the current sampling circuit, and the equivalent resistance value of the voltage sampling branch circuit 300 and the third resistor R3The ratio of the resistance values of (1) is the amplification factor of the load current signal, and the equivalent resistance value of the voltage sampling branch circuit 300 and the third resistor R are adjusted3The amplification factor of the voltage applied to the voltage sampling branch 300 can be adjusted according to the proportion of (2), so that an operational amplifier is not needed, and the design structure of the sampling circuit is simplified.
In the current sampling circuit disclosed in another embodiment of the present application, the structure of the voltage sampling branch 300 may be selected according to user requirements as long as it can provide a certain voltage division, for example, referring to fig. 2, in this scheme, the voltage sampling branch may be formed by only one resistor, which may be denoted as a fourth resistor R6Said fourth resistor R6Is connected to the second output terminal of the mirror current source 100, and the fourth resistor R6The second terminal of (3) is grounded, and the fourth resistor R6Is applied to the fourth resistor R as an output terminal of the current sampling circuit6The voltage at both ends is V7。
In the technical solution disclosed in another embodiment of the present application, a synchronous switch may be further included, which is denoted as a first synchronous switch, and the synchronous switch is disposed in the current sampling branch 201 and the load power supply branch 202, and is used for controlling the current sampling branch 201 and the load power supply branch 202 to be turned on when a current flows through the load power supply branch 202.
Specifically, referring to fig. 3, when there is one current sampling branch 201, the synchronous switch is denoted as a first synchronous switch, and the first synchronous switch may include:
first sampling MOS tube M1And a first load MOS transistor M2Wherein, the first sampling MOS tube M1And the first load MOS transistor M2May be the same, the first sampling MOS transistor M1And the first load MOS transistor M2Is interconnected, i.e. the first sampling MOS transistor M1First sampling MOS tube M1And the first load MOS tube M2And the first load MOS transistor M2The drain electrodes of the two electrodes are connected;
the first sampling MOS tube M1A first resistor R disposed between the first DC source DC1 and the first resistor4To (c) to (d);
the first load MOS transistor M2A resistor disposed between the second DC source DC2 and the third resistor R3The first load MOS tube M2Is connected with the input end.
In the above scheme, the first sampling MOS tube M1And a first load MOS transistor M2The first sampling MOS tube M has the same size and can be made to be the same regardless of channel modulation effect1And a first load MOS transistor M2The on-state of (c) is kept synchronous.
In a technical solution disclosed in another embodiment of the present application, the current regulating circuit 200 may include N current sampling branches 201, where the N current sampling branches 201 are connected in parallel, and N is a positive integer not less than 2, where second resistors R1 in different current sampling branches 201 are used to obtain target voltage signals output by different target voltage signal sources; in the technical solution disclosed in the embodiment of the present application, the target voltage signal source may be a dc output circuit in a power supply converter that supplies power to the load, and the current sampling branch 201 and the dc output circuit have a unique corresponding relationship, that is, each dc output circuit in the power supply converter may serve as a target voltage signal source, and the current sampling branch 201 corresponding to the target voltage signal source applies the target voltage signal.
The current sampling circuit further includes: a mirror current selection switch for selecting a switch for a maximum target voltage signal by the mirror current source 100First resistor R in current sampling branch 201 corresponding to source4And a second resistor R1The voltage at the two ends is used as a control signal, and the current output by the first output end of the mirror current source 100 is guided to the load power supply branch 202; specifically, the mirror current source 100 selection switch includes: n selection switch MOS tubes M corresponding to the N current sampling branches 201 one by one3Each selection switch MOS transistor M3Is connected to a first output terminal of the mirror current source 100, an output terminal and the third resistor R3The end which is not connected with the load is connected, and the control end is connected with the output end of the first direct current power supply in the current sampling branch 201 corresponding to the control end.
When the current sampling branch 201 is N, the synchronous switch is marked as a second synchronous switch, and the second synchronous switch is arranged in the current sampling branch and the load power supply branch and used for controlling the conduction of the N current sampling branches and the load power supply branch when current flows through the load power supply branch. Specifically, the second synchronous switch includes: the current sampling circuit comprises N second sampling MOS tubes and a second load MOS tube, wherein each current sampling branch is internally provided with one second sampling MOS tube; each second sampling MOS tube is arranged between a second direct current source and a first resistor in the corresponding current sampling branch; the second load MOS tube is arranged between the second direct current source and the third resistor, and the control end and the input end of the second load MOS tube are connected; and the N second sampling MOS tubes are interconnected with the control ends of the second load MOS tubes.
For example, referring to fig. 4, taking the value of N as 2 as an example, the structure and the operation principle of the current sampling circuit are explained, and the current sampling circuit may include: two current sampling branches 201 with the same structure, a second synchronous switch and two selection switch MOS transistors, in order to facilitate the distinction, in this embodiment, the elements in different current sampling branches 201 and different selection switch MOS transistors M3For example, one of the current sampling branches 201 is referred to as a first current sampling branch 201a, and the second synchronous switch is located at the first current sampling branchThe second sampling MOS transistor in the sample branch 201a is marked as MN2The first resistance in the first current sampling branch 201a is denoted as R4The second resistance in the first current sampling branch 201a is denoted as R1Another current sampling branch 201 is marked as a second current sampling branch 201b, and a second sampling MOS transistor in the second synchronous switch and located in the second current sampling branch 201b is marked as MN3The first resistance in the second current sampling branch 201b is denoted as R5The second resistance in the second current sampling branch 201b is denoted as R2The selection switch MOS transistor connected to the first current sampling branch 201a is denoted as MN4The selection switch MOS transistor connected to the second current sampling branch 201b is denoted as MN5And the second load MOS transistor is marked as MN1；
At this time, the working principle of the current sampling circuit is as follows:
in FIG. 2, MOS transistor MN1～～MN3Same size, neglecting channel modulation effects, assuming MN4And MN5All have current, then due to MN1～～MN3All work in a saturation region, and V is easily known by combining with a saturation region formula of an MOS (metal oxide semiconductor) tube4＝V5＝V6The following equation is also obtained:
V1+(I1+I2+I3)*R3＝V2+I1*R4
V1+(I1+I2+I3)*R3＝V3+I1*R5
since R3 ═ R4 ═ R5, the following were obtained:
(I2+I3)*R3＝V2-V1
(I2+I3)*R3＝V3-V1
when V is2-V1And V3-V1When equal, I2 and I3 may be in any combination, assuming that I3 is equal to 0:
Figure BDA0002661255690000101
when V is2-V1And V3-V1When not equal, combining formula (I)2+I3)*R3＝V2-V1And (I)2+I3)*R3＝V3-V1It can be seen that hypothesis MN4And MN5Both currents are incorrect, only one of them can be on, and the other is in off state. V easy to learn by inference2-V1And V3-V1And the NMOS corresponding to the branch with larger medium pressure difference is conducted. E.g. V2-V1＞V3-V1Then M isN4Conducting a current flowing through, MN5In the off state, i.e. I3When the value is equal to 0, then
Figure BDA0002661255690000102
Synthesis of the above analysis and formulas
Figure BDA0002661255690000103
And formula
Figure BDA0002661255690000104
It is understood that the resistor R may be used in the current sampling circuit1And a resistance R2The one with larger voltage difference between two ends is selected and converted into a voltage signal V7Passed to the next module, resistor R6And a resistance R3The ratio of (a) is the amplification factor of the load current signal, and the value of the V7 signal output by the current sampling circuit is
Figure BDA0002661255690000105
The derivation of the formula shows that as long as the matching of the first current sampling branch and the second current sampling branch is ensured, the current sampling circuit can realize equal current sampling coefficients, so that the detection precision caused by process mismatch is also considered in the real design processInfluence. In order to further weaken the influence of the channel modulation effect of the MOS transistor on the measurement result, the MOS transistor M in the technical scheme disclosed in the embodiment of the present applicationN1MOS transistor MN2And MOS transistor MN3The grid length of (2) is recommended to be 5um or more; in order to improve the matching degree and reduce the influence of mismatch on the MOS transistor MN1MOS tube MN2And MOS transistor MN3The gate width of the MOS transistor M is also recommended to be 5um or more, and meanwhile, when a circuit is designed, in order to ensure the reliability of the working state of the circuit, the MOS transistor M can be arranged onN1MOS transistor MN2And MOS transistor MN3Redundant devices are also added at both ends of the device.
In the above circuit, in order to facilitate signal output and input of the current sampling circuit, the above circuit may further include a plurality of voltage ports and a plurality of signal output ports, the voltage ports correspond to the current sampling branches 201 one to one, and each voltage port corresponds to the first resistor R of the corresponding current sampling branch 2014And a second resistor R1For providing a target voltage signal to the current sampling branch 201, for example, in the above scheme, the voltage ports may refer to port a and port B in fig. 4; the signal output port is connected to the first end of the voltage sampling branch 300, and is used for outputting a detection voltage, and the signal output port may be referred to as a port C in fig. 4.
In the above-mentioned scheme disclosed in the embodiment of the present application, the first sampling MOS transistor M1First load MOS transistor M2And the type of the selection switch MOS tube can be selected according to the requirements of users, for example, the first sampling MOS tube M1First load MOS transistor M2And the selection switch MOS tube can be both N-type MOS tubes, and similarly, two MOS tubes in the mirror current source can be both P-type MOS tubes, for example, the mirror current source in FIG. 2 is composed of P-type MOS tube MP1And P type MOS tube MP2And (4) forming.
In the technical solution disclosed in the embodiment of the present application, in order to simplify the circuit structure, the first direct current source DC1 in the current sampling branch 201 and the second direct current source DC2 in the load power supply branch 202 may be the same direct current power supply.
Corresponding to the current sampling circuit, the application also discloses a power supply converter applying the current sampling circuit switched on in any one of the embodiments.
In the above power supply variation, the power supply variation device has a dc output circuit, an output terminal of the dc output circuit and the first resistor R in the current sampling circuit4And a second resistor R1The dc output circuit is configured to provide a target voltage signal as the target voltage signal source, N dc output circuits may be provided in the power supply converter, the current sampling branches 201 may correspond to the dc output circuits one to one, and the second resistors R in the current sampling branches 201 are connected to each other1The end which is not connected with the load is connected with the output end of the corresponding direct current output circuit, and the direct current output circuit is used as the target voltage signal source to provide the target voltage signal for the corresponding current sampling branch 201.
Further, in order to ensure the stability of the output signal of the power supply converter, an output current modulation module is further arranged in the power supply converter, and the modulation mode is used for outputting a current modulation signal to a direct current output circuit in the power supply converter based on a comparison result of a voltage value of the first end of the fourth resistor R6 of the current sampling circuit and a preset voltage value, so that the output current of the direct current output circuit changes along with the change of the current modulation signal.
Referring to fig. 4, in the present scheme, the current modulation module and part of the components in the current sampling circuit are packaged in a high-precision current sampling module, and part of the components in the current sampling circuit refers to the second resistor R in the current sampling branch 2011Other elements than the above.
Referring to fig. 5, the power supply converter provided in the embodiment of the present application may be a power supply converter having a plurality of DC output circuits DC-DC, where the number of DC output circuits DC-DC in the power supply converter and the current sampling branches in the current sampling circuit201, see fig. 5, and the output terminal of each power supply transformer is connected to the second resistor R in one of the current sampling branches 2011Is connected to the first terminal of the first resistor R, the second resistor R1The first terminal of (b) is said second resistance R1And the first resistor R4One end connected to each other.
The embodiments in the present description are described in a progressive manner, each embodiment focuses on differences from other embodiments, and the same and similar parts among the embodiments are referred to each other. The device disclosed by the embodiment corresponds to the method disclosed by the embodiment, so that the description is simple, and the relevant points can be referred to the method part for description.
The previous description of the disclosed embodiments is provided to enable any person skilled in the art to make or use the present invention. Various modifications to these embodiments will be readily apparent to those skilled in the art, and the generic principles defined herein may be applied to other embodiments without departing from the spirit or scope of the invention. Thus, the present invention is not intended to be limited to the embodiments shown herein but is to be accorded the widest scope consistent with the principles and novel features disclosed herein.

Claims (13)

1. A current sampling circuit, comprising:
the device comprises a mirror current source, a current regulating circuit and a voltage sampling branch circuit;
the first output end of the mirror current source is connected with a current source interface of the current regulating circuit, the second output end of the mirror current source is grounded through the voltage sampling branch, and the common end of the mirror current source and the voltage sampling branch is used as the output end of the current sampling circuit;
the output end of the current regulating circuit is connected with a load, and the current regulating circuit is used for controlling the output current of the mirror current source to change along with the change of the current input to the load.
2. The current sampling circuit of claim 1, wherein the current regulation circuit 200 comprises: the device comprises a current sampling branch and a load power supply branch;
the current sampling branch circuit comprises a first direct current source, a first resistor and a second resistor which are sequentially connected in series, wherein one end, which is not connected with the first resistor, of the second resistor is connected with the input end of the load, and one end, which is connected with the first resistor, of the second resistor is used for acquiring a target voltage signal output by a target voltage signal source;
the load power supply branch comprises a second direct current source and a third resistor which are sequentially connected in series, the input end of the second direct current source is connected with the input end of the first direct current source, and the end, which is not connected with the second direct current source, of the third resistor is connected with the input end of the load;
and the first output end of the mirror current source is connected with the common end of the second direct current source and the third resistor.
3. The current sampling circuit of claim 2, wherein the voltage sampling branch comprises:
and the first end of the fourth resistor is connected with the second output end of the mirror current source, the second end of the fourth resistor is grounded, and the first end of the fourth resistor is used as the output end of the current sampling circuit.
4. The current sampling circuit of claim 2, further comprising:
and the first synchronous switches are arranged in the current sampling branch and the load power supply branch and are used for controlling the current sampling branch and the load power supply branch to be conducted when current flows through the load power supply branch.
5. The current sampling circuit of claim 4, wherein the first synchronous switch comprises:
the device comprises a first sampling MOS tube and a first load MOS tube;
the first sampling MOS tube is arranged between the first direct current source and the first resistor;
the first load MOS tube is arranged between the second direct current source and the third resistor, and the control end and the input end of the first load MOS tube are connected;
and the control ends of the first sampling MOS tube and the first load MOS tube are interconnected.
6. The current sampling circuit according to claim 2, wherein the current regulating circuit 200 includes N current sampling branches, the N current sampling branches are connected in parallel, N is a positive integer not less than 2, and second resistors in different current sampling branches are used to obtain target voltage signals output by different target voltage signal sources;
the current sampling circuit further includes: a mirror current selection switch;
the mirror current selection switch comprises N selection switch MOS tubes in one-to-one correspondence with the N current sampling branches, the input end of each selection switch MOS tube is connected with the first output end of the mirror current source, the output end of each selection switch MOS tube is connected with one end of the third resistor, which is not connected with the load, and the control end of each selection switch MOS tube is connected with the output end of the first current source in the corresponding current sampling branch.
7. The current sampling circuit of claim 6, further comprising:
and the second synchronous switches are arranged in the current sampling branch and the load power supply branch and are used for controlling the conduction of the N current sampling branches and the load power supply branch when current flows through the load power supply branch.
8. The current sampling circuit of claim 7, wherein the second synchronous switch comprises:
the current sampling circuit comprises N second sampling MOS tubes and a second load MOS tube, wherein each current sampling branch is internally provided with one second sampling MOS tube;
each second sampling MOS tube is arranged between a second direct current source and a first resistor in the corresponding current sampling branch;
the second load MOS tube is arranged between the second direct current source and the third resistor, and the control end and the input end of the second load MOS tube are connected;
and the N second sampling MOS tubes are interconnected with the control ends of the second load MOS tubes.
9. The current sampling circuit of claim 2, wherein the target voltage signal source is a dc output circuit in a power converter that supplies power to the load.
10. A power converter, comprising: the current sampling circuit of any one of claims 1-9.
11. A power converter as claimed in claim 10, comprising a dc output circuit for providing a target voltage signal as said target voltage signal source.
12. A power converter according to claim 10,
the current sampling branch circuits are in one-to-one correspondence with the direct current output circuits, one end, which is not connected with a load, of the second resistor in each current sampling branch circuit is connected with the output end, which corresponds to the second resistor, of the direct current output circuit, and the direct current output circuit serves as the target voltage signal source to provide a target voltage signal for the corresponding current sampling branch circuit.
13. A power converter as recited in claim 10, further comprising:
and the output current modulation module is used for outputting a current modulation signal to a direct current output circuit in the power supply converter based on a comparison result of the voltage signal of the output end of the current sampling circuit and a preset voltage signal, so that the output current of the direct current output circuit changes along with the change of the current modulation signal.
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Cited By (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
CN112491012A (en) * 2021-02-03 2021-03-12 四川蕊源集成电路科技有限公司 Current-limiting double-protection circuit and current-limiting double-protection method of circuit
CN113252949A (en) * 2021-05-13 2021-08-13 北京芯格诺微电子有限公司 High-precision current sampling circuit with on-chip real-time calibration
CN116031830A (en) * 2023-03-28 2023-04-28 深圳市德晟达电子科技有限公司 Load switch protection circuit adopting impedance detection

Citations (8)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
GB1233822A (en) * 1968-02-27 1971-06-03 Comp Generale Electricite An electric current monitoring device
JP2004336164A (en) * 2003-04-30 2004-11-25 Asahi Kasei Microsystems Kk Current output circuit
US20070268643A1 (en) * 2006-05-22 2007-11-22 Mediatek Singapore Pte Ltd Current limiter system, circuit and method for limiting current
CN103257665A (en) * 2012-02-17 2013-08-21 安凯(广州)微电子技术有限公司 Non-capacitive low-dropout linear voltage stabilizing system and bias current regulating circuit thereof
WO2013130480A1 (en) * 2012-03-01 2013-09-06 Sandisk Technologies Inc. Programmable slew rate power switch
CN206788232U (en) * 2017-04-24 2017-12-22 深圳市华芯邦科技有限公司 Buck converter load current detection circuits with compensation circuit
CN107894530A (en) * 2017-12-25 2018-04-10 峰岹科技（深圳）有限公司 Negative voltage detection circuit and motor driver
CN110045174A (en) * 2019-05-24 2019-07-23 南京酷科电子科技有限公司 A kind of current sampling circuit

Patent Citations (8)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
GB1233822A (en) * 1968-02-27 1971-06-03 Comp Generale Electricite An electric current monitoring device
JP2004336164A (en) * 2003-04-30 2004-11-25 Asahi Kasei Microsystems Kk Current output circuit
US20070268643A1 (en) * 2006-05-22 2007-11-22 Mediatek Singapore Pte Ltd Current limiter system, circuit and method for limiting current
CN103257665A (en) * 2012-02-17 2013-08-21 安凯(广州)微电子技术有限公司 Non-capacitive low-dropout linear voltage stabilizing system and bias current regulating circuit thereof
WO2013130480A1 (en) * 2012-03-01 2013-09-06 Sandisk Technologies Inc. Programmable slew rate power switch
CN206788232U (en) * 2017-04-24 2017-12-22 深圳市华芯邦科技有限公司 Buck converter load current detection circuits with compensation circuit
CN107894530A (en) * 2017-12-25 2018-04-10 峰岹科技（深圳）有限公司 Negative voltage detection circuit and motor driver
CN110045174A (en) * 2019-05-24 2019-07-23 南京酷科电子科技有限公司 A kind of current sampling circuit

Non-Patent Citations (2)

* Cited by examiner, † Cited by third party
Title
MOHAMED ATEF: "High gain transimpedance amplifier with current mirror load", 《2014 PROCEEDINGS OF THE 21ST INTERNATIONAL CONFERENCE MIXED DESIGN OF INTEGRATED CIRCUITS AND SYSTEMS (MIXDES)》 *
刘鸿雁 等: "一种应用于LDO稳压器的CMOS误差放大电路的设计", 《中国集成电路》 *

Cited By (4)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
CN112491012A (en) * 2021-02-03 2021-03-12 四川蕊源集成电路科技有限公司 Current-limiting double-protection circuit and current-limiting double-protection method of circuit
CN112491012B (en) * 2021-02-03 2021-04-16 四川蕊源集成电路科技有限公司 Current-limiting double-protection circuit and current-limiting double-protection method of circuit
CN113252949A (en) * 2021-05-13 2021-08-13 北京芯格诺微电子有限公司 High-precision current sampling circuit with on-chip real-time calibration
CN116031830A (en) * 2023-03-28 2023-04-28 深圳市德晟达电子科技有限公司 Load switch protection circuit adopting impedance detection

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