CN109752585A - The adjustable current testing circuit of detection accuracy - Google Patents
The adjustable current testing circuit of detection accuracy Download PDFInfo
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- CN109752585A CN109752585A CN201910075566.3A CN201910075566A CN109752585A CN 109752585 A CN109752585 A CN 109752585A CN 201910075566 A CN201910075566 A CN 201910075566A CN 109752585 A CN109752585 A CN 109752585A
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Abstract
The invention discloses a kind of adjustable circuits of current detection accuracy, comprising: programmable controller, current precision control circuit and operational amplification circuit, wherein current precision control circuit includes amplification factor control circuit and current sampling circuit.The first end of amplification factor control circuit and the I/O interface of programmable controller connect, and the first input end of second end and operational amplification circuit connects.The first end of current sampling circuit and the I/O interface of programmable controller connect, and the second input terminal of second end and operational amplification circuit connects.The output end of operational amplification circuit and the AD conversion interface of programmable controller connect.Beneficial effects of the present invention: current detection accuracy is adjustable, and detection accuracy is high；Test can be switched in working condition, standby mode and power-down state to camera module, and is switched flexible；Structure is simple, and current detection range is wide, and detection efficiency is high.
Description
Technical field
The present invention relates to the technical field of mobile phone camera module group current detecting, in particular to a kind of detection accuracy is adjustable
Current testing circuit.
Background technique
Mobile phone belongs to mobile device, is powered using battery, and the requirement to power consumption is very harsh, interior of mobile phone device work
Therefore the duration that size of current when making directly affects power consumption and battery uses in the test of mobile phone camera module group, needs
Will working condition to camera module, standby mode, power-down state electric current test.
Currently, detection accuracy about mobile phone camera module group current detection circuit is not high, is unable to satisfy to camera mould
Group is accurately tested in the electric current of working condition, standby mode and power-down state, and cannot flexible switch test circuit, with right
Camera module is tested in working condition, standby mode and power-down state.
Summary of the invention
In view of the problems of the existing technology, the main object of the present invention is to provide a kind of adjustable electric current survey of detection accuracy
Try circuit, it is intended to which the detection accuracy for solving existing mobile phone camera module group current detection circuit is not high, and cannot flexibly switch
The problem of.
To achieve the above object, the adjustable current testing circuit of detection accuracy proposed by the present invention, comprising: PLC technology
Device, current precision control circuit and operational amplification circuit, wherein current precision control circuit include amplification factor control circuit and
Current sampling circuit.The first end of amplification factor control circuit and the I/O interface of programmable controller connect, second end and fortune
Calculate the first input end connection of amplifying circuit.The first end of current sampling circuit and the I/O interface of programmable controller connect,
The connection of second input terminal of second end and operational amplification circuit.The output end of operational amplification circuit and the AD of programmable controller turn
Alias connection.
Amplification factor control circuit includes: the first metal-oxide-semiconductor Q1, the second metal-oxide-semiconductor Q2 and third metal-oxide-semiconductor Q3.First metal-oxide-semiconductor
The drain interconnection of Q1, the second metal-oxide-semiconductor Q2 and third metal-oxide-semiconductor Q3, the source electrode of the first metal-oxide-semiconductor Q1 and the first end of first resistor R1 connect
It connects, the source electrode of the second metal-oxide-semiconductor Q2 is connect with the first end of second resistance R2, and the source electrode of third metal-oxide-semiconductor Q3 is with 3rd resistor R3's
First end connection, the second end interconnection of first resistor R1, second resistance R2 and 3rd resistor R3.First metal-oxide-semiconductor Q1, the 2nd MOS
The grid of pipe Q2 and third metal-oxide-semiconductor Q3 are connect with the I/O interface of PLC technology.
Operational amplification circuit includes: the first operational amplifier U1, second operational amplifier U2 and third operational amplifier U3.
The drain electrode of the backward end of first operational amplifier U1 and the first metal-oxide-semiconductor Q1, the drain electrode of the second metal-oxide-semiconductor Q2, the 3rd MOS
The connection of the first end of the drain electrode of pipe Q3 and the 4th resistance R4.End in the same direction and the current sampling circuit of first operational amplifier U1 connects
It connects.The output end of first operational amplifier U1 is connect with the first end of the second end of the 4th resistance R4 and the 5th resistance R5.
The backward end and the second end of first resistor R1, the second end of second resistance R2, third of second operational amplifier U2
The second end of resistance R3 and the connection of the first end of the 6th resistance R6.The end in the same direction of second operational amplifier U2 and current sampling circuit
Connection.The output end of second operational amplifier U2 is connect with the first end of the second end of the 6th resistance R6 and the 8th resistance R8.
The backward end of third operational amplifier U3 is connect with the first end of the second end of the 5th resistance R5 and the 9th resistance R9.
The end in the same direction of third operational amplifier U3 is connect with the first end of the second end of the 8th resistance R8 and the tenth resistance R10, the tenth electricity
Hinder the second end ground connection of R10.The output end of third operational amplifier U3 and the second end and programmable controller of the 9th resistance R9
AD conversion interface connection.
Current sampling circuit includes: the 4th metal-oxide-semiconductor Q4, the 5th metal-oxide-semiconductor Q5, the 6th metal-oxide-semiconductor Q6, the 7th metal-oxide-semiconductor Q7, the 8th
Metal-oxide-semiconductor Q8 and the 9th metal-oxide-semiconductor Q9.
The drain interconnection of 4th metal-oxide-semiconductor Q4, the 5th metal-oxide-semiconductor Q5 and the 6th metal-oxide-semiconductor Q6 and confession with camera module to be measured
Power supply connection.The source electrode of 4th metal-oxide-semiconductor Q4 is connect with the first end of the drain electrode of the 7th metal-oxide-semiconductor Q7 and eleventh resistor R11, the
The source electrode of five metal-oxide-semiconductor Q5 is connect with the first end of the drain electrode of the 8th metal-oxide-semiconductor Q8 and twelfth resistor R12, the source of the 6th metal-oxide-semiconductor Q6
Pole is connect with the first end of the drain electrode of the 9th metal-oxide-semiconductor Q9 and thirteenth resistor R13, eleventh resistor R11, twelfth resistor R12
And the second end of thirteenth resistor R13 is connected with the end in the same direction of second operational amplifier U2.The grid of 4th metal-oxide-semiconductor Q4 and
The gate interconnection of seven metal-oxide-semiconductor Q7, and connect with the I/O interface of programmable controller.The grid and the 8th metal-oxide-semiconductor of 5th metal-oxide-semiconductor Q5
The gate interconnection of Q8, and connect with the I/O interface of programmable controller.The grid of 6th metal-oxide-semiconductor Q6 and the grid of the 9th metal-oxide-semiconductor Q9
Pole interconnection, and connect with the I/O interface of programmable controller.The source of 7th metal-oxide-semiconductor Q7, the 8th metal-oxide-semiconductor Q8 and the 9th metal-oxide-semiconductor Q9
Pole interconnection, and connected with the end in the same direction of the first operational amplifier U1.
Preferably, it successively contacts between the end in the same direction of the first operational amplifier U1 and the end in the same direction of second operational amplifier U2
It is connected to first capacitor C1 and the 7th resistance R7.
Preferably, the end in the same direction of the first operational amplifier U1 is connected with first diode D1 and the second diode D2, and first
The interconnection of the forward end of diode D1 and the second diode D2, and the limiting voltage outside the reversed termination of first diode D1, the
The backward end of two diode D2 is grounded.The end in the same direction of second operational amplifier U2 is connected with third diode D3 and the 4th diode
The forward end of D4, third diode D3 and the 4th diode D4 interconnect, and the clipping outside the reversed termination of third diode D3
Voltage, the backward end ground connection of the 4th diode D4.
Preferably, programmable controller is single-chip microcontroller.
Compared with prior art, the beneficial effects of the present invention are: current detection accuracy is adjustable, and detection accuracy is high；It can be right
Camera module switches over test in working condition, standby mode and power-down state, and switches flexible；Structure is simple, electricity
It is wide to flow detection range, and detection efficiency is high.
Detailed description of the invention
In order to more clearly explain the embodiment of the invention or the technical proposal in the existing technology, to embodiment or will show below
There is attached drawing needed in technical description to be briefly described, it should be apparent that, the accompanying drawings in the following description is only this
Some embodiments of invention for those of ordinary skill in the art without creative efforts, can be with
The structure shown according to these attached drawings obtains other attached drawings.
Fig. 1 is the working principle diagram of adjustable one embodiment of current testing circuit of detection accuracy of the present invention；
Fig. 2 is the connection structure diagram of amplification factor control circuit and operational amplification circuit in one embodiment of the invention；
Fig. 3 is the working principle diagram of current sampling circuit in one embodiment of the invention；
Fig. 4 is the operation principle schematic diagram of one group of metal-oxide-semiconductor switch of two metal-oxide-semiconductors composition in one embodiment of the invention；
The object of the invention is realized, the embodiments will be further described with reference to the accompanying drawings for functional characteristics and advantage.
Specific embodiment
The present invention proposes a kind of adjustable current testing circuit of detection accuracy.
Referring to Fig.1-3, Fig. 1 is the working principle diagram of adjustable one embodiment of current testing circuit of detection accuracy of the present invention,
Fig. 2 is the connection structure diagram of amplification factor control circuit and operational amplification circuit in one embodiment of the invention, and Fig. 3 is the present invention one
The working principle diagram of current sampling circuit in embodiment.
As shown in Figure 1, in embodiments of the present invention, the adjustable current testing circuit of the detection accuracy, comprising: programmable control
Device 100, current precision control circuit and operational amplification circuit 400 processed, wherein current precision control circuit includes times magnification numerical control
Circuit 200 and current sampling circuit 300 processed.The first end of amplification factor control circuit 200 and the IO of programmable controller 100 connect
Mouth connection, second end are connect with the first input end of operational amplification circuit 400.The first end of current sampling circuit 300 with can
The I/O interface of programmable controller 100 connects, and second end is connect with the second input terminal of operational amplification circuit 400.Operation amplifier
The output end of circuit 400 is connect with the AD conversion interface of programmable controller 100.
As shown in Fig. 2, amplification factor control circuit 200 includes: the first metal-oxide-semiconductor Q1, the second metal-oxide-semiconductor Q2 and third metal-oxide-semiconductor
Q3.The drain interconnection of first metal-oxide-semiconductor Q1, the second metal-oxide-semiconductor Q2 and third metal-oxide-semiconductor Q3, the source electrode and first resistor of the first metal-oxide-semiconductor Q1
The first end of R1 connects, and the source electrode of the second metal-oxide-semiconductor Q2 is connect with the first end of second resistance R2, the source electrode of third metal-oxide-semiconductor Q3 and
The first end of 3rd resistor R3 connects, the second end interconnection of first resistor R1, second resistance R2 and 3rd resistor R3.First MOS
The grid of pipe Q1, the second metal-oxide-semiconductor Q2 and third metal-oxide-semiconductor Q3 are connect with the I/O interface of PLC technology.Wherein, first resistor
The resistance value of R1, second resistance R2 and 3rd resistor R3 are different, three different proportion resistors of composition resistance value, for controlling the fortune
Calculate the amplification factor of amplifying circuit 400., can be different according to electric current gear to be tested when work, pass through programmable controller 100
The conducting of corresponding metal-oxide-semiconductor is controlled, and selects corresponding proportion resistor, to realize the control to current amplification factor to be measured.
As shown in Fig. 2, operational amplification circuit 400 includes: the first operational amplifier U1, second operational amplifier U2 and third
Operational amplifier U3.
The drain electrode of the backward end of first operational amplifier U1 and the first metal-oxide-semiconductor Q1, the drain electrode of the second metal-oxide-semiconductor Q2, the 3rd MOS
The connection of the first end of the drain electrode of pipe Q3 and the 4th resistance R4.End in the same direction and the current sampling circuit 300 of first operational amplifier U1
Connection.The output end of first operational amplifier U1 is connect with the first end of the second end of the 4th resistance R4 and the 5th resistance R5.
The backward end and the second end of first resistor R1, the second end of second resistance R2, third of second operational amplifier U2
The second end of resistance R3 and the connection of the first end of the 6th resistance R6.The end in the same direction of second operational amplifier U2 and current sampling circuit
300 connections.The output end of second operational amplifier U2 is connect with the first end of the second end of the 6th resistance R6 and the 8th resistance R8.
The backward end of third operational amplifier U3 is connect with the first end of the second end of the 5th resistance R5 and the 9th resistance R9.
The end in the same direction of third operational amplifier U3 is connect with the first end of the second end of the 8th resistance R8 and the tenth resistance R10, the tenth electricity
Hinder the second end ground connection of R10.The output end of third operational amplifier U3 and the second end and programmable controller of the 9th resistance R9
100 AD conversion interface connection.When work, the electric current of camera module to be measured is through the AD conversion interface of programmable controller 100
After inputing to programmable controller 100, by programmable controller 100 through analog-to-digital conversion, voltage signal is reduced into actual samples
The size of electric current.
First operational amplifier U1, second operational amplifier U2 and third operational amplifier U3 form differential amplifier circuit base
This structure, the ability with good inhibition null offset and inhibition noise and interference.
Specifically, in the present embodiment, the end in the same direction of the first operational amplifier U1 and second operational amplifier U2's is in the same direction
First capacitor C1 and the 7th resistance R7 is successively serially connected between end.First capacitor and the 7th resistance play buffer function, filter out
High-frequency percussion electric current and interference signal, further increase detection accuracy.
Specifically, in the present embodiment, the end in the same direction of the first operational amplifier U1 is connected with first diode D1 and second
The interconnection of the forward end of diode D2, first diode D1 and the second diode D2, and the reversed termination of first diode D1 is external
Limiting voltage, the second diode D2 backward end ground connection.The end in the same direction of second operational amplifier U2 is connected with third diode
The interconnection of the forward end of D3 and the 4th diode D4, third diode D3 and the 4th diode D4, and third diode D3's is reversed
Limiting voltage outside termination, the backward end ground connection of the 4th diode D4.Wherein, first diode D1 and the second diode D2,
Third diode D3 and the 4th diode D4 separately constitute amplitude limiter circuit, are used for resistance to compression and anti-interference protection.
As shown in figure 3, current sampling circuit 300 includes: the 4th metal-oxide-semiconductor Q4, the 5th metal-oxide-semiconductor Q5, the 6th metal-oxide-semiconductor Q6,
Seven metal-oxide-semiconductor Q7, the 8th metal-oxide-semiconductor Q8 and the 9th metal-oxide-semiconductor Q9.
The drain interconnection of 4th metal-oxide-semiconductor Q4, the 5th metal-oxide-semiconductor Q5 and the 6th metal-oxide-semiconductor Q6 and confession with camera module to be measured
Power supply connection.The source electrode of 4th metal-oxide-semiconductor Q4 is connect with the first end of the drain electrode of the 7th metal-oxide-semiconductor Q7 and eleventh resistor R11, the
The source electrode of five metal-oxide-semiconductor Q5 is connect with the first end of the drain electrode of the 8th metal-oxide-semiconductor Q8 and twelfth resistor R12, the source of the 6th metal-oxide-semiconductor Q6
Pole is connect with the first end of the drain electrode of the 9th metal-oxide-semiconductor Q9 and thirteenth resistor R13, eleventh resistor R11, twelfth resistor R12
And the second end of thirteenth resistor R13 is connected with the end in the same direction of the second operational amplifier U2 in operational amplification circuit 400.The
The grid of four metal-oxide-semiconductor Q4 and the gate interconnection of the 7th metal-oxide-semiconductor Q7, and connect with the I/O interface of programmable controller 100.5th
The gate interconnection of the grid of metal-oxide-semiconductor Q5 and the 8th metal-oxide-semiconductor Q8, and connect with the I/O interface of programmable controller 100.6th MOS
The gate interconnection of the grid of pipe Q6 and the 9th metal-oxide-semiconductor Q9, and connect with the I/O interface of programmable controller 100.7th metal-oxide-semiconductor
The source electrode of Q7, the 8th metal-oxide-semiconductor Q8 and the 9th metal-oxide-semiconductor Q9 interconnects, and with the first operational amplifier U1 in operational amplification circuit 400
End in the same direction connection.When work, the 4th metal-oxide-semiconductor Q4 and the 7th metal-oxide-semiconductor Q7, the 5th metal-oxide-semiconductor Q5 and the 8th metal-oxide-semiconductor Q8 and the 6th
Metal-oxide-semiconductor Q6 and the 9th metal-oxide-semiconductor Q9 separately constitutes three groups of metal-oxide-semiconductor switches, eleventh resistor R11, twelfth resistor R12 and the 13rd
Resistance R13 separately constitutes the different current sampling resistor of resistance value.The gate interconnection of two metal-oxide-semiconductors in every group of metal-oxide-semiconductor switch, and even
It is connected to the I/O interface of programmable controller 100, so that the metal-oxide-semiconductor switch in every group can be controlled simultaneously, and corresponding shelves can be gated
The current sampling resistor of position.Every group of metal-oxide-semiconductor switch is connect with operational amplification circuit 400, so that an operational amplification circuit 400
The sample rate current that multiple gears can be tested, enormously simplifies circuit structure.
When need to camera module to be measured working condition, standby mode and power-down state any state carry out electric current
When detection, one group of metal-oxide-semiconductor switch conduction of respective notch, electric current flows through current sampling resistor, and the two of current sampling resistor
End generates pressure drop, since 400 input impedance of operational amplification circuit is infinitely great, so, flow through the 7th metal-oxide-semiconductor Q7 or the 8th metal-oxide-semiconductor
The electric current of Q8 or the 9th metal-oxide-semiconductor Q9 are 0, so that the collected operational amplification circuit that the pressure drop at current sampling resistor both ends is lossless
400 amplify processing so that the current sampling circuit 300 not only can flexible switch sampling testing current gear, but also
It can guarantee that sampled signal is lossless.Specifically, in the present embodiment, as shown in figure 4, to need to camera module to be measured in work
Make for state carries out current detecting, the metal-oxide-semiconductor switch conduction that the 4th metal-oxide-semiconductor Q4 and the 7th metal-oxide-semiconductor Q7 are formed, electric current flows through the
11 resistance R11, and pressure drop is generated at the both ends eleventh resistor R11, since 400 input impedance of operational amplification circuit is infinitely great,
So the electric current for flowing through the 7th metal-oxide-semiconductor Q7 is 0, so that the lossless collected operation of the pressure drop at current sampling resistor both ends is put
Big circuit 400 amplifies processing.
Skill scheme of the invention by being arranged in current sampling circuit 300 by the 4th metal-oxide-semiconductor Q4 and the 7th metal-oxide-semiconductor Q7,
Three groups of metal-oxide-semiconductors of the 5th metal-oxide-semiconductor Q5 and the 8th metal-oxide-semiconductor Q8 and the 6th metal-oxide-semiconductor Q6 and the 9th metal-oxide-semiconductor Q9 composition switch, every group of MOS
Pipe switch is connect with the I/O interface of programmable controller 100, is controlled every group of metal-oxide-semiconductor and is switched on-off, to realize switch test.Often
The electricity that group metal-oxide-semiconductor switch is formed from the eleventh resistor R11 of different resistance values, twelfth resistor R12 and thirteenth resistor R13 respectively
Sampling resistor connection is flowed, to realize respectively to the electric current of the working condition of camera module to be measured, standby mode and power-down state
It is sampled.By being arranged in amplification factor control circuit 200 by the first metal-oxide-semiconductor Q1, the second metal-oxide-semiconductor Q2 and third metal-oxide-semiconductor Q3
The grid of the three road metal-oxide-semiconductors switch of composition, every road metal-oxide-semiconductor switch is connect with the I/O interface of programmable controller 100, controls every road
Metal-oxide-semiconductor switches on-off.The source electrode of every road metal-oxide-semiconductor switch is separately connected first resistor R1, second resistance R2 and 3rd resistor R3,
First resistor R1, second resistance R2 and 3rd resistor R3 form the magnification ratio resistance of different resistance values, control electricity to be measured to realize
The amplification factor of stream.And by by current sampling circuit 300 and amplification factor control circuit 200 with operational amplification circuit 400
And programmable controller 100 connects, to realize that precisely detection camera module is in working condition, standby mode and power-down state
Electric current.
Preferably, in the present embodiment, programmable controller 100 is single-chip microcontroller.
It is described further below for better implementation technical solution of the present invention:
In the first embodiment of the present embodiment, the resistance value of eleventh resistor R11 is 1 ohm, twelfth resistor R12
Resistance value be 1K ohm, the resistance value of thirteenth resistor R13 is 100K ohm, respectively corresponds camera module to be measured in the shape that works
The current sampling resistor value of state, standby mode and power-down state.The resistance value of first resistor R1 is 10K ohm, second resistance R2's
Resistance value is 1K ohm, and the resistance value of 3rd resistor R3 is 100 ohm, and the resistance value of the 4th resistance R4 is 50K ohm, the 6th resistance R6's
Resistance value is 50K ohm.
When detecting the operating current of camera module to be measured, the I/O interface of programmable controller 100 exports high level control
The first metal-oxide-semiconductor Q1, the 4th metal-oxide-semiconductor Q4 and the 7th metal-oxide-semiconductor Q7 conducting are made, the I/O interface of programmable controller 100 exports low level
Control the second metal-oxide-semiconductor Q2, third metal-oxide-semiconductor Q3, the 5th metal-oxide-semiconductor Q5, the 8th metal-oxide-semiconductor Q8, the 6th metal-oxide-semiconductor Q6 and the 9th metal-oxide-semiconductor Q9
Cut-off, calculates the amplification factor of voltage difference: Vout=(V2-V1) (R1+R4+R6)/R1, wherein (R1+R4+R6)/R1 is fixed
Value, so that it is determined that the amplification factor of voltage difference V2-V1, therefore, the amplification factor of operational amplification circuit 400 are (R1+R4+
R6)/R1=(10K+50K+50K)/10K=11.
If sampling eleventh resistor R11 both ends pressure drop at this time is 0.3V, eleventh resistor in current sampling circuit 300
The both ends pressure drop signal of R11 is input to operational amplification circuit 400.The pressure difference at the both ends eleventh resistor R11 is through operational amplification circuit
It is 3.3V after 400 11 times of progress amplifications, this voltage signal is exported to the AD conversion interface of programmable controller 100, programmable control
The internal processes of device 100 processed carry out electric current reduction and calculate；Voltage/amplification factor/sampling resistor=3.3V/11/1=0.3A, because
And the operating current for measuring camera module to be measured is 0.3A.
When detecting the standby current of camera module to be measured, the I/O interface of programmable controller 100 exports high level control
The second metal-oxide-semiconductor Q2, the 5th metal-oxide-semiconductor Q5 and the 8th metal-oxide-semiconductor Q8 conducting are made, the I/O interface of programmable controller 100 exports low level
Control the first metal-oxide-semiconductor Q1, the 4th metal-oxide-semiconductor Q4, the 7th metal-oxide-semiconductor Q7, third metal-oxide-semiconductor Q3, the 6th metal-oxide-semiconductor Q6 and the 9th metal-oxide-semiconductor Q9
Cut-off, calculates the amplification factor of voltage difference: Vout=(R2+R4+R6)/R2=(1K+50K+50K)/1K, wherein (R2+R4+
R6)/R2 is definite value, so that it is determined that the amplification factor of voltage difference V2-V1, therefore, the amplification factor of operational amplification circuit 400 is
(R2+R4+R6)/R2=(1K+50K+50K)/1K=101.
If sampling twelfth resistor R12 both ends pressure drop at this time is 0.03V, the 12nd electricity in current sampling circuit 300
The both ends pressure drop signal of resistance R12 is input to operational amplification circuit 400.The pressure difference at the both ends twelfth resistor R12 is through operation amplifier electricity
Road 400 is 3.03V after carrying out 101 times of amplifications, this voltage signal is exported to the AD conversion interface of programmable controller 100, can be compiled
The internal processes of range controller 100 carry out electric current reduction and calculate；Voltage/amplification factor/sampling resistor=3.03V/101/1000R
=30uA, thus, the operating current for measuring camera module to be measured is 30uA.
When detecting the power down electric current of camera module to be measured, the I/O interface of programmable controller 100 exports high level control
Third metal-oxide-semiconductor Q3, the 6th metal-oxide-semiconductor Q6 and the 9th metal-oxide-semiconductor Q9 conducting processed, the I/O interface of programmable controller 100 export low level
Control the first metal-oxide-semiconductor Q1, the 4th metal-oxide-semiconductor Q4, the 7th metal-oxide-semiconductor Q7, the second metal-oxide-semiconductor Q2, the 5th metal-oxide-semiconductor Q5 and the 8th metal-oxide-semiconductor Q8
Cut-off, calculates the amplification factor of voltage difference: Vout=(R3+R4+R6)/R3=(100R+50K+50K)/100, wherein (R3+R4
+ R6)/R3 is definite value, so that it is determined that the amplification factor of voltage difference V2-V1, therefore, the amplification factor of operational amplification circuit 400
For (R3+R4+R6)/R3=(100R+50K+50K)/100R=1001.
If sampling thirteenth resistor R13 both ends pressure drop at this time is 0.003V, the 13rd electricity in current sampling circuit 300
The both ends pressure drop signal of resistance R13 is input to operational amplification circuit 400.The pressure difference at the both ends thirteenth resistor R13 is through operation amplifier electricity
Road 400 is 3.003V after carrying out 1001 times of amplifications, this voltage signal is exported to the AD conversion interface of programmable controller 100, can
The internal processes of programmable controller 100 carry out electric current reduction and calculate；Voltage/amplification factor/sampling resistor=3.003V/1001/
100000R=30nA, thus, the operating current for measuring camera module to be measured is 30nA.
Compared with prior art, the beneficial effects of the present invention are: current detection accuracy is adjustable, and detection accuracy is high；It can be right
Camera module switches over test in working condition, standby mode and power-down state, and switches flexible；Structure is simple, electricity
It is wide to flow detection range, and detection efficiency is high.
The above description is only a preferred embodiment of the present invention, is not intended to limit the scope of the invention, all at this
Under the inventive concept of invention, using equivalent structure transformation made by description of the invention and accompanying drawing content, or directly/use indirectly
It is included in other related technical areas in scope of patent protection of the invention.
Claims (4)
1. a kind of adjustable current testing circuit of detection accuracy characterized by comprising programmable controller, current precision control
Circuit and operational amplification circuit processed, wherein the current precision control circuit includes amplification factor control circuit and current sample
Circuit；The first end of the amplification factor control circuit is connect with the I/O interface of the programmable controller, second end and institute
State the first input end connection of operational amplification circuit；The IO of the first end of the current sampling circuit and the programmable controller
Interface connection, second end are connect with the second input terminal of the operational amplification circuit；The output end of the operational amplification circuit
It is connect with the AD conversion interface of the programmable controller；
The amplification factor control circuit includes: the first metal-oxide-semiconductor Q1, the second metal-oxide-semiconductor Q2 and third metal-oxide-semiconductor Q3；First MOS
The of the drain interconnection of pipe Q1, the second metal-oxide-semiconductor Q2 and third metal-oxide-semiconductor Q3, the source electrode of the first metal-oxide-semiconductor Q1 and first resistor R1
One end connection, the source electrode of the second metal-oxide-semiconductor Q2 are connect with the first end of second resistance R2, the source electrode of the third metal-oxide-semiconductor Q3
It is connect with the first end of 3rd resistor R3, the second end interconnection of the first resistor R1, second resistance R2 and 3rd resistor R3；Institute
The grid for stating the first metal-oxide-semiconductor Q1, the second metal-oxide-semiconductor Q2 and third metal-oxide-semiconductor Q3 is connect with the I/O interface of the PLC technology；
The operational amplification circuit includes: the first operational amplifier U1, second operational amplifier U2 and third operational amplifier U3；
The drain electrode of the backward end of the first operational amplifier U1 and the first metal-oxide-semiconductor Q1, the drain electrode of the second metal-oxide-semiconductor Q2, the
The drain electrode of three metal-oxide-semiconductor Q3 and the first end connection of the 4th resistance R4；End in the same direction and the electricity of the first operational amplifier U1
Flow sample circuit connection；The output end of the first operational amplifier U1 and the second end of the 4th resistance R4 and the 5th resistance R5's
First end connection；
The second end of the backward end of the second operational amplifier U2 and the first resistor R1, the second end of second resistance R2,
The second end of 3rd resistor R3 and the connection of the first end of the 6th resistance R6；The second operational amplifier U2 it is in the same direction end with it is described
Current sampling circuit connection；The output end of the second operational amplifier U2 and the second end and the 8th resistance R8 of the 6th resistance R6
First end connection；
The backward end of the third operational amplifier U3 is connect with the first end of the second end of the 5th resistance R5 and the 9th resistance R9；
The end in the same direction of the third operational amplifier U3 is connect with the first end of the second end of the 8th resistance R8 and the tenth resistance R10, institute
State the second end ground connection of the tenth resistance R10；The output end of the third operational amplifier U3 and the second of the 9th resistance R9
The connection of the AD conversion interface of end and programmable controller；
The current sampling circuit includes: the 4th metal-oxide-semiconductor Q4, the 5th metal-oxide-semiconductor Q5, the 6th metal-oxide-semiconductor Q6, the 7th metal-oxide-semiconductor Q7, the 8th
Metal-oxide-semiconductor Q8 and the 9th metal-oxide-semiconductor Q9；
The drain interconnection of the 4th metal-oxide-semiconductor Q4, the 5th metal-oxide-semiconductor Q5 and the 6th metal-oxide-semiconductor Q6 and confession with camera module to be measured
Power supply connection；The drain electrode of the source electrode and the 7th metal-oxide-semiconductor Q7 of the 4th metal-oxide-semiconductor Q4 and the first end of eleventh resistor R11 connect
It connecing, the source electrode of the 5th metal-oxide-semiconductor Q5 is connect with the first end of the drain electrode of the 8th metal-oxide-semiconductor Q8 and twelfth resistor R12, and described
The source electrode of six metal-oxide-semiconductor Q6 is connect with the first end of the drain electrode of the 9th metal-oxide-semiconductor Q9 and thirteenth resistor R13, the eleventh resistor
The second end of R11, twelfth resistor R12 and thirteenth resistor R13 are held in the same direction with the second operational amplifier U2 and are connect；Institute
The grid of the 4th metal-oxide-semiconductor Q4 and the gate interconnection of the 7th metal-oxide-semiconductor Q7 are stated, and is connected with the I/O interface of the programmable controller
It connects；The grid of the 5th metal-oxide-semiconductor Q5 and the gate interconnection of the 8th metal-oxide-semiconductor Q8, and the IO with the programmable controller
Interface connection；The gate interconnection of the grid of the 6th metal-oxide-semiconductor Q6 and the 9th metal-oxide-semiconductor Q9, and with the PLC technology
The I/O interface of device connects；The interconnection of the source electrode of the 7th metal-oxide-semiconductor Q7, the 8th metal-oxide-semiconductor Q8 and the 9th metal-oxide-semiconductor Q9, and with described the
One operational amplifier U1 holds connection in the same direction.
2. the adjustable current testing circuit of detection accuracy as described in claim 1, which is characterized in that first operation amplifier
The electricity of first capacitor C1 and the 7th is successively serially connected between the end in the same direction of device U1 and the end in the same direction of the second operational amplifier U2
Hinder R7.
3. the adjustable current testing circuit of detection accuracy as described in claim 1, which is characterized in that first operation amplifier
The end in the same direction of device U1 is connected with first diode D1 and the second diode D2, the first diode D1 and second diode
The forward end of D2 interconnects, and the limiting voltage outside the reversed termination of the first diode D1, and the second diode D2's is reversed
End ground connection；The end in the same direction of the second operational amplifier U2 is connected with third diode D3 and the 4th diode D4, the third
The forward end of diode D3 and the 4th diode D4 interconnects, and the clipping outside the reversed termination of the third diode D3
Voltage, the backward end ground connection of the 4th diode D4.
4. the adjustable current testing circuit of detection accuracy as described in any one of claims 1-3, which is characterized in that described to compile
Range controller is single-chip microcontroller.
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| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN201910075566.3A CN109752585A (en) | 2019-01-25 | 2019-01-25 | The adjustable current testing circuit of detection accuracy |
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| Application Number | Priority Date | Filing Date | Title |
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| CN201910075566.3A CN109752585A (en) | 2019-01-25 | 2019-01-25 | The adjustable current testing circuit of detection accuracy |
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| CN201910075566.3A Pending CN109752585A (en) | 2019-01-25 | 2019-01-25 | The adjustable current testing circuit of detection accuracy |
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Citations (3)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN101839936A (en) * | 2009-03-19 | 2010-09-22 | 北京普源精电科技有限公司 | Current measurement device |
| CN104569545A (en) * | 2014-12-11 | 2015-04-29 | 许继集团有限公司 | Wide-range measurement control circuit for Rogowski-coil-based current transformer |
| CN105954624A (en) * | 2016-06-17 | 2016-09-21 | 丰郅(上海)新能源科技有限公司 | Detection device |
-
2019
- 2019-01-25 CN CN201910075566.3A patent/CN109752585A/en active Pending
Patent Citations (3)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN101839936A (en) * | 2009-03-19 | 2010-09-22 | 北京普源精电科技有限公司 | Current measurement device |
| CN104569545A (en) * | 2014-12-11 | 2015-04-29 | 许继集团有限公司 | Wide-range measurement control circuit for Rogowski-coil-based current transformer |
| CN105954624A (en) * | 2016-06-17 | 2016-09-21 | 丰郅(上海)新能源科技有限公司 | Detection device |
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