CN109521254A - Current detection circuit and power supply device with the current detection circuit - Google Patents
Current detection circuit and power supply device with the current detection circuit Download PDFInfo
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- CN109521254A CN109521254A CN201811608671.0A CN201811608671A CN109521254A CN 109521254 A CN109521254 A CN 109521254A CN 201811608671 A CN201811608671 A CN 201811608671A CN 109521254 A CN109521254 A CN 109521254A
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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
Abstract
The present invention provides a kind of current detection circuit, including two input terminals, operational amplifier, PMOS tube, compensation current circuit, first resistor, second resistance and output resistance；The grid of PMOS tube, source electrode and drain electrode connect the output end of operational amplifier, the inverting input terminal of operational amplifier and output resistance respectively；First input end and the second input terminal are connect by selected on-off circuit with second resistance one end；The other end of second resistance and compensation current circuit one end are connect with the non-inverting input terminal of operational amplifier；The both ends of first resistor are connect with the non-inverting input terminal of first input end and operational amplifier respectively.The present invention provides a kind of power supply device including current detection circuit.Compared with prior art the beneficial effects of the present invention are: the collective effect by compensating current circuit and selected on-off circuit, can eliminate influence of the operational amplifier mismatch to testing result at the phenomenon that capable of eliminating the drift generated in current detection circuit.The detection accuracy of the current detection circuit is high.
Description
Technical field
The invention belongs to technical field of current detection more particularly to a kind of current detection circuits and one kind to have current detecting
The power supply device of circuit.
Background technique
Current detection circuit can be used for power source charges monitoring and overcurrent protection.Common electric current detecting method is first in electricity
A small detection resistance is added in logical circulation road, detection resistance both ends will form the pressure drop of very little immediately, then will test resistance
The pressure drop at both ends, to one voltage signal proportional to tested electric current of output, finally realizes electric current after amplifier amplifies
Detection.Involved detection resistance resistance value needs very little to ignore the power consumption of its generation, while guaranteeing detection resistance two again
End, which is formed, can be amplified the pressure drop that device accurately amplifies.
In addition, defining in technical field of current detection, when the detection resistance is located at if power end, electric current at this time is examined
It surveys and is referred to as high side current detection, when detection resistance is located at if ground terminal, current detecting at this time is referred to as low side current detecting.
Although common current detection circuit is able to carry out current detecting, there is also certain defect, defect is: by
In there are mismatches for the amplifier of introducing the case where, therefore, current detection circuit can there is a phenomenon where drifts.Zero drift phenomenon will affect
The measurement accuracy of current detection circuit.
It should be explained that: the voltage signal that zero drift phenomenon refers to that detection circuit exports when tested electric current is zero is not zero.
Summary of the invention
In view of this, the present invention provides a kind of electric current inspection in order to solve the problems, such as that zero drift phenomenon influences current detection accuracy
Slowdown monitoring circuit, the current detection circuit can eliminate drift by alignment mechanism, can be realized electric current by the current detection circuit
Accurate detection.
The present invention provides a kind of current detection circuit comprising two input terminals, operational amplifier, PMOS tube, compensation electricity
Current circuit, first resistor, second resistance and output resistance；The grid of the PMOS tube, source electrode and drain electrode connect the operation respectively
The output end of amplifier, the inverting input terminal of the operational amplifier and the output resistance；First input end and the second input
End is connect by selected on-off circuit with described second resistance one end；The other end of the second resistance and compensation electric current electricity
Road one end is connect with the non-inverting input terminal of the operational amplifier；The both ends of the first resistor are inputted with described first respectively
End is connected with the non-inverting input terminal of the operational amplifier.
Preferably, the selected on-off circuit includes the first switch branch and second switch branch for selecting a conducting, it is described
First switch branch is arranged between the first input end and the second resistance, and the second switch branch is arranged described
Between second input terminal and the second resistance；When first switch branch conducting, the current detection circuit enters school
Quasi-mode；When second switch branch conducting, the current detection circuit enters detection pattern.
Preferably, the selected on-off circuit include singly open double control switch, by it is described singly open double control switch formation select one
The first switch branch and the second switch branch of conducting.
Preferably, including first switch in the first switch branch, the first switch is inputted with described first respectively
End is connected with the second resistance；The second switch branch includes second switch, and the second switch is respectively with described second
Input terminal is connected with the second resistance.
Preferably, the first input end and second input terminal are respectively used to connect detection resistance high potential side and low
Current potential side, the current detection circuit is for exporting the voltage value V proportional to the electric current for flowing through the detection resistance；It is described
Voltage value V is indicated are as follows: V=Vsense2-Vsense1, in formula, Vsense1Expression flows through the first resistor under the calibration mode
On the pressure drop that is generated on the output resistance of electric current, Vsense2Expression flows through the first resistor under the detection pattern
On the pressure drop that is generated on the output resistance of electric current.
Preferably, flowing through the electric current in the first resistor when the current detection circuit enters the calibration mode
The pressure drop V generated on the output resistancesense1It indicates are as follows: Vsense1=(Ios×R2-Vos)×Rout÷R1, in formula, IosFor
The main line electric current of the compensation current circuit, R2For the resistance value of the second resistance, VosFor the mismatch electricity of the operational amplifier
Pressure, RoutFor the resistance value of the output resistance, R1For the resistance value of the first resistor.
Preferably, flowing through the electric current in the first resistor when the current detection circuit enters the detection pattern
The pressure drop V generated on the output resistancesense2It indicates are as follows: Vsense2=(Iload×Rs+ Ios × R2-Vos × Rout ÷ R1,
In formula, in formula, Iload is the electric current for flowing through the detection resistance, RsFor the resistance value of the detection resistance, IosFor the benefit
Repay the main line electric current of current circuit, R2For the resistance value of the second resistance, VosFor the misalignment voltage of the operational amplifier, Rout
For the resistance value of the output resistance, R1For the resistance value of the first resistor.
Preferably, the compensation current circuit includes that multiple electric currents come together in compensation branch main line and parallel with one another,
Every compensation branch road has been designed with switch member.
Preferably, one end of the compensation current circuit other end and the output resistance is grounded；The current detecting
The output voltage point of circuit is arranged between the drain electrode of the PMOS tube and the output resistance.
The present invention also provides a kind of power supply devices comprising power supply device ontology, the power supply device further include as above-mentioned
Described in any item current detection circuits；The power supply device ontology includes power supply module and the detection connecting with power supply module electricity
Resistance, the first input end and second input terminal are separately connected high potential side and the low potential one of the detection resistance
Side.
Compared with prior art the beneficial effects of the present invention are:
By compensating the collective effect of current circuit and selected on-off circuit, it can eliminate and be produced in the current detection circuit
The phenomenon that raw drift, influence of the operational amplifier mismatch to testing result can be eliminated.The detection of the current detection circuit
Precision is high.
Detailed description of the invention
It in order to more clearly explain the technical solutions in the embodiments of the present application, below will be to embodiment or description of the prior art
Needed in attached drawing be briefly described, it should be apparent that, the accompanying drawings in the following description is only some of the application
Embodiment for those of ordinary skill in the art without any creative labor, can also be according to these
Attached drawing obtains other attached drawings.
Fig. 1 is the structural schematic diagram of current detection circuit in the embodiment of the present invention 1；
Fig. 2 is the structural schematic diagram that current circuit is compensated in the embodiment of the present invention 1.
Appended drawing reference:
First input end 1, the second input terminal 2, selected on-off circuit, operational amplifier 3, PMOS tube 4, compensation current circuit
5, first resistor 6, second resistance 7, output resistance 8, first switch 9, second switch 10, output voltage point 11, power supply module 12,
Detection resistance 13, load 14, first node 15, second node 16, equivalence element 17, first compensate current device 18 and first and open
Close part 19.
Specific embodiment
Below in conjunction with attached drawing, the forgoing and additional technical features and advantages are described in more detail.
In the description of the present invention, it is to be understood that, term " first ", " second " are used for description purposes only, and cannot
It is interpreted as indication or suggestion relative importance or implicitly indicates the quantity of indicated technical characteristic.Define as a result, " the
One ", the feature of " second " can explicitly or implicitly include at least one of the features.In the description of the present invention, " multiple "
It is meant that at least two, unless otherwise specifically defined.
In the present invention unless specifically defined or limited otherwise, term " installation ", " connected ", " connection ", " fixation " etc.
Term shall be understood in a broad sense, for example, it may be being fixedly connected, may be a detachable connection, or integral；It can be mechanical connect
It connects, is also possible to be electrically connected or can communicate each other；It can be directly connected, can also indirectly connected through an intermediary, it can be with
It is the interaction relationship of the connection or two elements inside two elements, unless otherwise restricted clearly.For this field
For those of ordinary skill, the specific meanings of the above terms in the present invention can be understood according to specific conditions.
In the description of this specification, reference term " one embodiment ", " some embodiments ", " example ", " specifically show
The description of example " or " some examples " etc. means specific features, structure, material or spy described in conjunction with this embodiment or example
Point is included at least one embodiment or example of the invention.
In being described below, for illustration and not for limitation, the tool of such as particular system structure, technology etc is proposed
Body details, to understand thoroughly the embodiment of the present invention.However, it will be clear to one skilled in the art that there is no these specific
The present invention also may be implemented in the other embodiments of details.In other situations, it omits to well-known system, device, electricity
The detailed description of road and method, in case unnecessary details interferes description of the invention.
In the present specification, the schematic representation of the above terms does not necessarily have to refer to the same embodiment or example.
Moreover, particular features, structures, materials, or characteristics described can be in any one or more of the embodiments or examples with suitable
Mode combines.In addition, without conflicting with each other, those skilled in the art can be by difference described in this specification
The feature of embodiment or example and different embodiments or examples is combined.
In order to illustrate technical solutions according to the invention, the following is a description of specific embodiments.
Embodiment 1
Fig. 1 is the structural schematic diagram of current detection circuit in the embodiment of the present invention 1；As shown in Figure 1, the embodiment of the present invention 1
A kind of current detection circuit is provided comprising first input end 1, the second input terminal 2, selected on-off circuit, operational amplifier 3,
PMOS tube 4, compensation current circuit 5, first resistor 6, second resistance 7 and output resistance 8.
First input end 1 and the second input terminal 2 are connect by selected on-off circuit with 7 one end of second resistance.PMOS tube 4
Grid, source electrode and drain electrode connect the output end of operational amplifier 3, the inverting input terminal of operational amplifier 3 and output resistance 8 respectively.
The other end of second resistance 7 and compensation 5 one end of current circuit are connect with the non-inverting input terminal of operational amplifier 3.Compensate electric current
5 other end of circuit ground connection.8 other end of output resistance ground connection, i.e. 8 low potential one end of output resistance are grounded.The both ends of first resistor 6
It is connect respectively with the non-inverting input terminal of first input end 1 and operational amplifier 3.
PMOS tube 4 refers to P type metal oxide semiconductor field-effect tube, and the English of metal oxide semiconductor field effect tube
Literary fame is known as Metal Oxide Semiconductor, abbreviation MOS.
First input end 1 and the second input terminal 2 are connect by selected on-off circuit with 7 one end of second resistance.In this implementation
In example, selected on-off circuit includes the first switch branch and second switch branch at total end, and the connection setting of first switch branch exists
Between first input end 1 and second resistance 7, the connection of second switch branch is arranged between the second input terminal 2 and second resistance 7.
Further, switch element, i.e. first switch 9 and second switch 10 are each provided in two switching branches.First opens
9 both ends are closed to connect with first input end 1 and second resistance 7 respectively.10 both ends of second switch respectively with the second input terminal 2 and second
Resistance 7 connects.Second resistance 7, first switch 9 and second switch 10 share a common end.That is second resistance 7, first switch 9
With each one end equipotential link of second switch 10.To define second resistance 7 and selected on-off circuit connecting convenient for illustrating circuit structure
Contact is first node 15, and in other words, second resistance 7, first switch 9 and each one end of second switch 10 are commonly connected to first segment
Point 15.In addition, defining 7 other end of second resistance and compensating the tie point of current circuit 5 is second node 16.At first node 15
Voltage be V1, the voltage at second node 16 is V2。
In view of the mismatch of operational amplifier 3 influences, can be considered as in second node 16 and 3 homophase input of operational amplifier
An equivalence element 17 is provided between end.
Circuit relevant to current detection circuit is loaded work piece circuit, and loaded work piece circuit includes power supply module 12, inspection
Measuring resistance 13 and load 14.13 one end of detection resistance is connect with power supply module 12, this one end connecting with power supply module 12 is inspection
High potential one end of measuring resistance 13.13 other end of detection resistance is connect with 14 one end of load, this one end connecting with load 14 is
Low potential one end of detection resistance 13.The other end ground connection of load 14.
First input end 1 and the second input terminal 2 are connected on loaded work piece circuit.Further, 1 He of first input end
Second input terminal 2 is connected to 13 both ends of detection resistance, and first input end 1 and high potential one end of detection resistance 13 are electrically connected
It connects, the second input terminal is electrically connected with low potential one end of detection resistance 13.In the present embodiment, power supply module 12 and detection resistance
The electrical connection of 13 one end, i.e. 12 output end of power supply module, high potential one end of detection resistance 13,1 three's equipotential of first input end
Connection.The voltage value of power supply module 12 is Vdd。
When loaded work piece circuit works normally, current detection circuit can be used in detecting the electric current of loaded work piece circuit.
Operational amplifier 3, PMOS tube 4, first resistor 6, second resistance 7,8 collective effect of output resistance will be worth for Vdd-V1
Voltage difference amplification, amplification factor be equal to output resistance 8 resistance value RoutWith the resistance value R of first resistor 61Quotient.That is voltage difference
Vdd-V1It is amplified Rout÷R1Times.So to sum up, detecting output voltage VsenseIt may be expressed as: Vsense=(Vdd-V1)×Rout÷
R1, at this point, ignoring the mismatch of operational amplifier 3.
13 1 terminating load 14 of detection resistance, another termination power supply module 12, this connection are typical high side current inspections
The connection of slowdown monitoring circuit.This connection can be realized with the form of voltage the electric current I for describing load 14loadThe function of parameter.It is negative
Carry 14 electric current IloadThe voltage value that parameter is able to use the both ends of detection resistance 13 is stated, i.e. the both ends of detection resistance 13
Voltage value can be expressed as Iload×Rs, RsIndicate the resistance value of detection resistance 13.
The non-inverting input terminal that current circuit 5 one terminates operational amplifier 3, other end ground connection are compensated, compensation current circuit 5 flows
The electric current crossed is Ios.When considering the influence of 3 mismatch of operational amplifier, 3 misalignment voltage V of operational amplifierosIt indicates, quite
In one equivalence element 17 of access between second node 16 and the non-inverting input terminal of operational amplifier 3.17 both ends of equivalence element
Voltage be Vos.In turn, the voltage V of the non-inverting input terminal of operational amplifier 3+=V1-Ios×R2+Vos, R2Indicate second resistance 7
Resistance value.The inverting input terminal of operational amplifier 3 and the non-inverting input terminal void of operational amplifier 3 are short, therefore, operational amplifier 3
Inverting input terminal voltage V-It can indicate are as follows: V-=V+=V1-Ios×R2+Vos, detection output voltage can be obtained by being computed
Vsense, calculation formula are as follows: Vsense=(Vdd-V1+Ios×R2-Vos)×Rout÷R1.Detect output voltage VsenseFrom output voltage
11 output of point, output voltage point 11 are connect with the drain electrode of PMOS tube 4 and output resistance 8 respectively.
Fig. 2 is the structural schematic diagram that current circuit is compensated in the embodiment of the present invention 1.As shown in Fig. 2, compensation current circuit 5
Compensation branch main line and parallel with one another is come together in including multiple electric currents.There is switch member in every compensation branch road, in other words,
It include concatenated first compensation current device 18 and first switch part 19 in first compensation branch.Two companies of the first compensation branch
End is connect to connect with second node 16 and ground terminal respectively.In Fig. 2, it is preferable that first compensation 18 one end of current device ground connection, separately
One termination first switch part 19.First switch part 19 is also connect with second node 16.Further, the second compensation branch, third are mended
It is identical as the first compensation branch to repay the compensation branch structure such as branch.First compensation branch, the second compensation branch, third compensate branch
I is used respectively with the electric current of N compensation branchos1、Ios2、Ios3And IosnIt indicates, N is the positive integer greater than 1.Therefore, electric current is compensated
The electric current that circuit 5 flows through is IosIt can indicate are as follows: Ios=Ios1+Ios2+Ios3+…+Iosn.When the switch member in compensation branch is disconnected
When opening, the electric current of corresponding compensation branch is 0.When compensating the switch member closure in branch, the electric current of corresponding compensation branch can be with
Merge the main line electric current for being included in compensation current circuit 5.Based on this, can be adjusted by controlling the switch member in multiple compensation branches
The main line electric current I of section compensation current circuit 5osSize.
First switch 9 and second switch 10 are for realizing the calibration for detecting output voltage, when the closure of first switch 9 and second
V when switch 10 disconnectsdd=V1, current detection circuit enters calibration mode at this time, under calibration mode, flows through first resistor 6 and powers on
Flowing the pressure drop generated on output resistance 8 is Vsense1, can specifically indicate are as follows: Vsense1=(Ios×R2-Vos)×Rout÷R1；
When first switch 9 disconnects and second switch 10 is closed, current detection circuit enters detection pattern at this time, then has, Vdd-V1=
Iload×Rs, and under this mode, flowing through the pressure drop that electric current generates on output resistance 8 in first resistor 6 is Vsense2.Specifically may be used
To indicate are as follows:
Vsense2=(Iload×Rs+Ios×R2-Vos)×Rout÷R1；
Therefore, the practical output voltage V proportional to 14 electric currents of load is indicated are as follows:
V=Vsense2-Vsense1=Iload×Rs×Rout÷R1。
The parameter of the interlock circuits such as current detection circuit and loaded work piece circuit is preferably provided with value as described below:
The resistance value R of first resistor 61With the resistance value R of second resistance 72It is one kilohm.The resistance value R of output resistance 8outFor
45 kilo-ohms (45kOhm).Therefore, by Rout÷R1The calculated amplification factor of formula is 45.
The resistance value R of detection resistance 13sFor 20 milliohms (20mOhm), 14 electric current I is loadedloadFor 1.6A.Then by detection electricity
The pressure drop that resistance 13 is formed is 32mV.By the calculating process for the pressure drop that detection resistance 13 is formed are as follows: Iload×Rs=1.6A × 20mOhm
=32mV.
The standard deviation of 3 misalignment voltage of operational amplifier is 3.24mV, using 3 times of standard deviations as limit of consideration, then Vos=3 ×
3.24mV=9.72mV ≈ 10mV.
4 tunnels compensation branch (N=4), and I are shared in compensation current circuit 5os1=5uA, Ios2=5uA, Ios3=2.5uA,
Ios4=1.25uA.Embodiment can refer to but be not limited only to such parameter setting situation.
When current detection circuit is under calibration mode, the closure of first switch 9 and the disconnection of second switch 10, at this point, the
Voltage V at one node 151With the voltage value V of power supply module 12ddIt is equal.In the electric current I for considering compensation current circuit 5os
On the basis of, the voltage at second node 16 is V1-Ios×R2.Considering 3 misalignment voltage V of operational amplifierosOn the basis of, fortune
Calculating the voltage at 3 non-inverting input terminal of amplifier is V1-Ios×R2+Vos, therefore, the voltage at 3 inverting input terminal of operational amplifier
It can also be expressed as V1-Ios×R2+Vos.And falling in the pressure drop in first resistor 6 is Vdd-V1+Ios×R2-Vos, due to Vdd=V1,
Therefore, the pressure drop fallen in first resistor 6 is Ios×R2-Vos, then flowing through electric current in first resistor 6 is (Ios×R2-Vos)÷
R1.In turn, the pressure drop V that electric current in first resistor 6 generates on output resistance 8 is flowed throughsense1It is expressed as Vsense1=(Ios×R2-
Vos)×Rout÷R1, after bringing parameter into, Vsense1=45 (Ios×1kOhm-9.72mV).In order to guarantee Vsense1It is greater than zero
Value, then need Ios× 1kOhm > 9.72mV, therefore the first compensation branch and second is taken to compensate branch and connect, third compensates branch and the
Four compensation branches disconnect.At this point, Ios=Ios1+Ios2=10uA, and Vsense1=12.6mV.
Beneficial effect using multiple compensation branches is, can both guarantee the V exported in the case where zero loadsense1
It is a value just greater than zero, and V can be madesense2-Vsense1Sufficiently large, it is abundant that the detection of as load current reserves enough voltage
Degree.
When current detection circuit is under detection pattern, first switch 9 is disconnected and second switch 10 is closed.First node
Voltage V at 151It can indicate are as follows: V1=Vdd-Iload×Rs, in the electric current I for considering compensation current circuit 5osOn the basis of, the
Voltage at two nodes 16 is Vdd-Iload×Rs-Ios×R2.Considering 3 misalignment voltage V of operational amplifierosOn the basis of, operation
Voltage at 3 non-inverting input terminal of amplifier is Vdd-Iload×Rs-Ios×R2+Vos, electricity at 3 inverting input terminal of operational amplifier
Pressure can also be expressed as Vdd-Iload×Rs-Ios×R2+Vos, further, the pressure drop fallen in first resistor 6 is Iload×Rs+Ios
×R2-Vos, then flowing through electric current in first resistor 6 is (Iload×Rs+Ios× R2-Vos ÷ R1 flows through first resistor 6 in turn
The pressure drop Vsense2 that upper electric current generates on output resistance 8 be expressed as Vsense2=Iload × Rs+Ios × R2-Vos ×
Rout ÷ R1, after bringing parameter into, the value of Vsense2 is 1.4526V, and calculating process is Vsense2=1.6A × 20mOhm × 45+
12.6mV=1.4526V.
The practical output voltage V=V proportional to 14 electric currents of loadsense2-Vsense1=1.44V.
Therefore, the embodiment of the invention provides a kind of high-side current detection circuits, are opened by changing first switch 9 and second
10 switch state is closed to switch calibration mode and detection pattern, while the size by adjusting compensation electric current Ios guarantees calibration
Output detection voltage is value not less than zero under mode, by what is exported under the detection voltage and calibration mode that export under detection pattern
Detection voltage, which makes the difference, can be obtained detection voltage value only proportional to load current.
The present embodiment also provides a kind of power supply device comprising the current detection circuit, and power supply device includes power supply device
Ontology, power supply device ontology include power supply module 12 and the detection resistance connecting with power supply module 12 13.Current detection circuit
First input end 1 and the second input terminal 2 are connected to the high potential side and low potential side of detection resistance 13.
Embodiment 2
This embodiment differs from embodiment 1 in that the embodiment of the present invention 1 provides a kind of current detection circuit, choosing
Selecting switching circuit is singly to open double control switch.First input end 1 and the second input terminal 2 are by singly opening double control switch and second resistance 7
One end connection.
In the present embodiment, the common end for singly opening double control switch is connect with second resistance 7, it can be understood as is singly opened dual control and is opened
The common end (non-moving end) of pass and second resistance 7 are connected at first node 15.Singly open double control switch further includes the first connection
End and second connection end, the first connecting pin are connect with first input end 1, and second connection end is connect with the second input terminal 2.Dan Kaishuan
First connecting pin and second connection end are selected one and form access with common end by control switch.Singly opening double control switch can also be logical at two kinds
Switching is executed between road.
In embodiment 1, first switch 9 closure and second switch 10 disconnect when, current detection circuit is in calibration mode
Under.And in the present embodiment, singly opening double control switch can be worked with a switch in place first switch 9 and second switch 10, that is, be worked as
When singly opening double control switch the first connecting pin being connected with common end, second connection end must be disconnected with common end, and electric current is examined at this time
Slowdown monitoring circuit enters under calibration mode.
In embodiment 1, first switch 9 disconnect and second switch 10 be closed when, current detection circuit is in detection pattern
Under.And in the present embodiment, singly opening double control switch can be worked with a switch in place first switch 9 and second switch, that is, work as list
When opening double control switch second connection end being connected with common end, the first connecting pin must be disconnected with common end, at this time current detecting
Circuit enters under detection pattern.
It is using double control switch is singly opened instead of the beneficial effect that first switch 9 and second switch 10 work, reduces work
It measures, reduces the risk of on-off control system error, improve the control harmony of switching circuit, improve switching circuit
Switching efficiency.Double control switch is singly opened suitable for automation control.
The present embodiment also provides a kind of power supply device comprising the current detection circuit, and power supply device includes power supply device
Ontology, power supply device ontology include power supply module 12 and the detection resistance connecting with power supply module 12 13.Current detection circuit
First input end 1 and the second input terminal 2 are connected to the high potential side and low potential side of detection resistance 13.
Embodiment described above is only to illustrate the technical solution of the application, rather than its limitations；Although referring to aforementioned reality
Example is applied the application is described in detail, those skilled in the art should understand that: it still can be to aforementioned each
Technical solution documented by embodiment is modified or equivalent replacement of some of the technical features；And these are modified
Or replacement, the spirit and scope of each embodiment technical solution of the application that it does not separate the essence of the corresponding technical solution should all
Comprising within the scope of protection of this application.
Claims (10)
1. a kind of current detection circuit, which is characterized in that including first input end, the second input terminal, operational amplifier, PMOS
Pipe, compensation current circuit, first resistor, second resistance and output resistance；The grid of the PMOS tube connects the operational amplifier
Output end, the source electrode of the PMOS tube connects the inverting input terminal of the operational amplifier, and the drain electrode of the PMOS tube connects described
Output resistance；The first input end and second input terminal are connected by selected on-off circuit and described second resistance one end
It connects；The other end of the second resistance and described compensation current circuit one end connect with the non-inverting input terminal of the operational amplifier
It connects；The both ends of the first resistor are connect with the non-inverting input terminal of the first input end and the operational amplifier respectively.
2. current detection circuit as described in claim 1, which is characterized in that the selected on-off circuit includes selecting a conducting
First switch branch and second switch branch, the first switch branch are arranged in the first input end and the second resistance
Between, the second switch branch is arranged between second input terminal and the second resistance；When the first switch branch
When road is connected, the current detection circuit enters calibration mode；When second switch branch conducting, the current detecting electricity
Road enters detection pattern.
3. current detection circuit as claimed in claim 2, which is characterized in that the selected on-off circuit includes singly opening dual control to open
It closes, passes through the first switch branch and the second switch branch singly opened double control switch formation and select a conducting.
4. current detection circuit as claimed in claim 2, which is characterized in that opened in the first switch branch including first
It closes, the first switch is connect with the first input end and the second resistance respectively；The second switch branch includes the
Two switches, the second switch are connect with second input terminal and the second resistance respectively.
5. such as the described in any item current detection circuits of claim 2-4, which is characterized in that the first input end and described the
Two input terminals are respectively used to connect detection resistance high potential side and low potential side, and the current detection circuit is for exporting and flowing
The proportional voltage value V of electric current through the detection resistance；The voltage value V is indicated are as follows: V=Vsense2-Vsense1, in formula,
Vsense1Expression flows through the pressure drop that the electric current in the first resistor generates on the output resistance under the calibration mode,
Vsense2Expression flows through the pressure drop that the electric current in the first resistor generates on the output resistance under the detection pattern.
6. current detection circuit as claimed in claim 5, which is characterized in that when the current detection circuit enters the calibration
When mode, the pressure drop V that the electric current in the first resistor generates on the output resistance is flowed throughsense1It indicates are as follows: Vsense1=
(Ios×R2-Vos)×Rout÷R1, in formula, IosFor the main line electric current of the compensation current circuit, R2For the second resistance
Resistance value, VosFor the misalignment voltage of the operational amplifier, RoutFor the resistance value of the output resistance, R1For the first resistor
Resistance value.
7. current detection circuit described in claim 5, which is characterized in that when the current detection circuit enters the detection mould
When formula, the pressure drop V that the electric current in the first resistor generates on the output resistance is flowed throughsense2It indicates are as follows: Vsense2=
(Iload×Rs+Ios×R2-Vos)×Rout÷R1, in formula, in formula, IloadFor the electric current for flowing through the detection resistance, RsFor
The resistance value of the detection resistance, IosFor the main line electric current of the compensation current circuit, R2For the resistance value of the second resistance, VosFor
The misalignment voltage of the operational amplifier, RoutFor the resistance value of the output resistance, R1For the resistance value of the first resistor.
8. current detection circuit as described in claim 1, which is characterized in that the compensation current circuit includes multiple current remittances
Compensation branch main line and parallel with one another is combined in, every compensation branch road has been designed with switch member.
9. such as the described in any item current detection circuits of claim 1-4,6-8, which is characterized in that the compensation current circuit is another
One end and one end of the output resistance are grounded；The PMOS tube is arranged in the output voltage point of the current detection circuit
Between drain electrode and the output resistance.
10. a kind of power supply device, including power supply device ontology, which is characterized in that the power supply device further includes such as claim
The described in any item current detection circuits of 1-9；The power supply device ontology includes power supply module and the inspection that connect with power supply module
Measuring resistance, the first input end connect the high potential side of the detection resistance, and second input terminal connects the detection
The low potential side of resistance.
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| CN201811608671.0A CN109521254A (en) | 2018-12-27 | 2018-12-27 | Current detection circuit and power supply device with the current detection circuit |
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Cited By (5)
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| CN110703837A (en) * | 2019-10-29 | 2020-01-17 | 北京东方计量测试研究所 | Earth current compensation circuit and method |
| CN113655265A (en) * | 2020-08-24 | 2021-11-16 | 成都芯源系统有限公司 | Integrated circuit for current detection, current detection circuit and calibration method thereof |
| CN113678002A (en) * | 2019-04-26 | 2021-11-19 | 株式会社自动网络技术研究所 | Current detection device and power supply control device |
| CN114546013A (en) * | 2022-01-26 | 2022-05-27 | 中山大学 | Reference starting circuit for detecting current by adopting comparator with mismatch |
| CN115932363A (en) * | 2022-12-16 | 2023-04-07 | 无锡中微爱芯电子有限公司 | Offset voltage adjustable high-side current detection circuit |
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