CN207689555U - A kind of low-leakage current restorer for Power Capacity parting weak current measuring circuit - Google Patents
A kind of low-leakage current restorer for Power Capacity parting weak current measuring circuit Download PDFInfo
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Abstract
The utility model belongs to weak current field of measuring technique, more particularly to a kind of low-leakage current restorer for Power Capacity parting weak current measuring circuit, it is connected to and treats in the Power Capacity parting weak current measuring circuit (2) that micrometer weak current (1) measures, including resetting current circuit (3), multiplexer (4), D/A converter (5), voltage follower (6), logic control element (7)；Shutdown voltage of the voltage of voltage follower (6) reproducible weak current to be measured (1) as resetting current circuit (3), D/A converter (5) can be the conducting voltage that resetting current circuit (3) provides that polarity and size can be adjusted；It further include the logic control element (7) of the polarity and size that control the conducting voltage that multiplexer (4) selects output shutdown voltage or conducting voltage, control D/A converter (5) to export.The measurement lower limit and least resolution of Power Capacity parting weak current measuring circuit system can be substantially improved in the utility model.
Description
Technical field
The utility model belongs to weak current field of measuring technique, and in particular to one kind being used for Power Capacity parting weak current
The low-leakage current restorer of measuring circuit.
Background technology
Generally by nA (10-9A) magnitude electric current below is known as weak current.In radiation detection, electrochemistry, new material etc.
In the scientific research in field, it is often necessary to carry out weak current measurement.Weak current measurement difficult point is not only only that be measured
The signal amplitude of amount is very small, due also to it is easy to be interfered by various types, even can be disturbed noise sometimes floods.It is dry
The type for disturbing source is not only Electronics noice, the frictional electricity that also electric field, magnetic field and electromagnetic field or even mechanical oscillation generate
Effect, applies the piezoelectric effect that external force generates, and the electrochemistry noise and insulating materials that electrochemical substance is mixed to form with moisture draw
The leakage current entered can all seriously affect the measurement result of weak current, or even make measurement that can not be normally carried out.Especially carrying out pA
(10-12A) grade or even fA (10-15A when) weak current of grade measures, these influences are especially apparent.The measurement of weak current at present
Method mainly has two major classes：
One kind is I-V converter techniques, and this method is by high value resistor (according to the size of electric current to be measured, usually 109Ω amounts
Grade is to 1011Ω magnitudes), low current signal to be measured is converted to the voltage signal for being easier to measure, passes through formulaJust
Current value can be calculated；
Another kind of is Power Capacity point-score (seeing Fig. 1 using the Power Capacity parting weak current measuring circuit of the method), this method
Charge is collected using integrating capacitor, with accumulation of the charge on capacitor plate, the voltage at capacitance both ends gradually increases, and passes through meter
The change rate in known capacitance capacitance terminal voltage in certain time is calculated, public affairs are passed throughThis can be calculated
The average value of electric current in the section time.Since the stability of capacitance relatively high value resistance is more preferable, temperature coefficient is lower, and capacitance is logical
The influence of some types Electronics noice and external disturbance can be inhibited by crossing the mode of integral.Therefore, Power Capacity point-score becomes compared with I-V
The method of changing is more appropriately applied to the higher occasion of measurement accuracy, as being widely used based on capacitance integral in ionising radiation metering field
The measuring device of method completes the measurement that various types ionisation chamber exports faint ionization current signal.
In measurement scheme based on Power Capacity point-score, an important process is to discharge the charge accumulated on capacitance, so as to
It is measured next time.In order to discharge this Partial charge, need that additional resetting apparatus is added.Currently, the realization of resetting apparatus
Form mainly passes through on-off mode and current source mode two types.On-off mode, i.e., it is in parallel with integrating capacitor using switching, when
Capacitance shorted on both ends discharges charge when switch conduction.This method is simple in structure, but because the leakage current introduced when split shutdown is opened has
High requirement, common transistor type switch cannot be satisfied requirement, therefore is generally used as and is opened using mechanical reed switch relay
It closes.The disadvantages of this method one is since the moment of a large amount of charge relay conducting electric discharges of capacitive accumulation can form big electric current punching
It hits, which is likely to result in wafer damage, can be produced because of Mechanical Contact and friction second is that mechanical relay disconnects moment
Raw charge, integrating capacitor generates voltage change after collecting, and the quantity of electric charge generated is uncontrollable, therefore can be had an impact to measurement.Cause
This generally relatively mostly uses current source mode, and this method is using constant-current source output with the opposite polarity electric current of input current to capacitance
Reverse charging is carried out, the charge of integrating capacitor is made to complete release, constant-current source circuit is made of field-effect tube or transistor mostly,
There are potential differences with input terminal for current potential when the constant-current source circuit shutdown of composition, such as the ionization being commonly used in radiation detection field
Its charge-trapping pole (i.e. current output terminal) current potential of room is often at tens millivolts, and (or PN junction is anti-for zero potential when being turned off with constant-current source
To bias potential) there are larger potential difference, which can form leakage current, mostly pA grades (10-12) or even nA (10 A-9A)
Grade, the leakage current not only will produce measurement error, but will influence the measurement lower limit of measuring circuit and minimum resolution capability.
Utility model content
It is big for current integration type weak current resetting apparatus leakage current, seriously affect circuit measuring lower limit and minimum resolution
The problem of ability, the utility model develop a kind of low-leakage current restorer, and the leakage current of the low-leakage current restorer is less than 1fA
(10-15A), and the adjustable bipolarity resetting current of output size may be implemented, to which low-leakage current restorer be greatly reduced
Influence to weak current measuring system measurement lower limit and minimum resolution capability, greatly improves the performance of weak current measuring system
Index.
To achieve the above objectives, the technical solution adopted in the utility model is a kind of for the survey of Power Capacity parting weak current
The low-leakage current restorer for measuring circuit is connected to and treats the Power Capacity parting weak current measurement electricity that micrometer weak current measures
On the road, include the output of the input terminal of output end connection resetting current circuit, input terminal connection voltage follower, D/A converter
The multiplexer at end, the output end of the resetting current circuit and the input terminal of the voltage follower are connected to the capacitance
The input terminal of integral form weak current measuring circuit；The voltage that the voltage follower can replicate the weak current to be measured is made
For the shutdown voltage of the resetting current circuit, the D/A converter can provide polarity and big for the resetting current circuit
The small conducting voltage that can be adjusted；When the multiplexer exports the shutdown voltage, the resetting current circuit shutdown,
When the multiplexer exports the conducting voltage, the resetting current circuit turn-on, and it is micro- to the Power Capacity parting
Weak current measurement circuit output resetting current；Further include for control multiplexer selection export the shutdown voltage or
The logic control list of the polarity and size of the conducting voltage and the conducting voltage of the control D/A converter output
Member.
Further, the circuit board of the low-leakage current restorer uses high insulating property plank, the plank to include at least
Ceramic wafer.
Further, it is arranged around the cabling on the output end of the resetting current circuit for exporting the resetting current
Protection ring, the protection ring is using the shutdown voltage of voltage follower output as clamping voltag, the protection ring
Windowing turmeric process is done, the gap exported between the cabling of the resetting current and the cabling of the protection ring is
15mil。
Further, between the shutdown voltage that the voltage follower provides and the voltage of the weak current to be measured
Potential difference is less than 10 μ V.
Further, described multiple when the logic control element selects to export the conducting voltage by the D/A converter
The resetting current of position current circuit output is A grades of resetting currents of μ, and the polarity and size of the resetting current are by the D/A
The polarity and size of the conducting voltage of converter output determine.
Further,
The resetting current circuit includes the resistance being connected in parallel between the input terminal and output end of the resetting current circuit
R1 and resistance R2；The resistance R1 series connection one diode D2, the diode D2 are located at the resistance R1 and the input terminal
Between, the resistance R1 is located at the positive side of the diode D2；One diode D1 of the resistance R2 series connection, two pole
For pipe D1 between the resistance R2 and the input terminal, the resistance R2 is located at the cathode side of the diode D1, described
Current-limiting resistance when resistance R1, resistance R2 are as the resetting current circuit turn-on prevents the resetting current excessive, also conduct
Divider resistance when the resetting current circuit shutdown reduces the diode terminal voltage；
The resistance R1, resistance R2 are metalfilmresistor, and resistance value is 1M Ω；
The diode D1, diode D2 are low reverse-bias leakage current diode PAD1；
The circuit being made of the resistance R1, diode D2 and the circuit difference being made of the resistance R2, diode D1
The resetting current of opposed polarity for D/A converter output；
The resetting current size I of the resetting current circuit outputResetBy formula (VDAC-VDiode)/R is obtained, wherein VDAC
For the conducting voltage of D/A converter output, VDiodeVoltage when being connected for the diode D1, diode D2, R is institute
State the resistance value of current-limiting resistance.
Further, the absolute value of the conducting voltage of the D/A converter output is not less than 1V.
Further, the voltage follower uses JFET grades of ultralow bias current Ib, low maladjustment voltage VosAmplifier, institute
It states amplifier and is configured to positive follower.
Further, the resetting current circuit that the resetting current circuit, voltage follower are formed is arranged in metallic shield
In box, and close to the Power Capacity parting weak current measuring circuit.
The beneficial effects of the utility model are：
1. the utility model is by using Low-bias Current IbWith the voltage V of low maladjustment voltageosVoltage follower 6, will
The voltage of the input terminal of voltage, that is, voltage follower 6 of weak current output end is used as to be measured for Power Capacity parting weak current
The shutdown voltage of the low-leakage current restorer of circuit, by the shutdown voltage of resetting current circuit 3 and Power Capacity parting weak current
The voltage difference of the input terminal of measuring circuit 2 is by mV magnitudes (10-3V μ V magnitudes (10) are reduced to-6V), reset electricity is considerably reduced
The level of drain current of current circuit 3.
2. the resetting current circuit 3 of the utility model is concatenated using low reverse bias leakage current diode and high value resistor
Connection type is used in the equivalent electricity of the low-leakage current restorer of Power Capacity parting weak current measuring circuit in the off case
Resistance increases considerably.
3. clamping voltag of the shutdown voltage that the utility model is exported using voltage follower 6 as protection ring, and coordinate
Baseplate material of the ceramic High Performance Insulation material as circuit board significantly reduces resetting current circuit 3 because insulating materials introduces
Leakage current.
4. the low-leakage current restorer provided by the utility model for Power Capacity parting weak current measuring circuit exists
Leakage current under off state is no more than 1fA, can be realized by D/A converter 5 to exporting the adjusting of polarities of potentials and size
Resetting current circuit 3 exports bipolarity and the adjustable μ A grades of resetting currents of size.
5. the utility model can by the measurement lower limit of Power Capacity parting weak current measuring circuit and least resolution by
PA grades (10-12A) it is promoted to fA grades (10-15A), the measurement performance of Power Capacity parting weak current measuring circuit is substantially improved.
Description of the drawings
Fig. 1 is the schematic diagram of the Power Capacity parting weak current measuring circuit described in the utility model background technology；
Fig. 2 is described in specific embodiment of the present invention for the low of Power Capacity parting weak current measuring circuit
The structure chart of leakage current restorer；In Fig. 2：1- weak currents to be measured, 2- Power Capacity parting weak current measuring circuits, 3- reset
Current circuit, 4- multiplexers, 5-D/A converters, 6- voltage followers, 7- logic control elements；
Fig. 3 is the circuit diagram of the voltage follower described in specific embodiment of the present invention；
Fig. 4 is the circuit diagram of the resetting current circuit described in specific embodiment of the present invention；
Fig. 5 be specific embodiment of the present invention described in D/A converter in output buffer and in proportion electricity
Press the circuit diagram of phase inverter；
Fig. 6 is the schematic diagram of the multiplexer MAX4518 described in specific embodiment of the present invention.
Specific implementation mode
The utility model is further described with reference to the accompanying drawings and examples.
A kind of low-leakage current restorer for Power Capacity parting weak current measuring circuit provided by the utility model is (such as
Shown in Fig. 2), it is connected to and treats in the Power Capacity parting weak current measuring circuit 2 that micrometer weak current 1 measures, including is multiple
Position current circuit 3, multiplexer 4, D/A converter 5, voltage follower 6, logic control element 7 etc..
The output end of resetting current circuit 3 is connected to the input terminal of Power Capacity parting weak current measuring circuit 2, resets electricity
The output end of the input terminal connection multiplexer 4 of current circuit 3, for according to the shutdown voltage of the output of multiplexer 4 or
Conducting voltage is closed or is connected to Power Capacity parting weak current measuring circuit 2；
The output end of multiplexer 4 is connected to the input terminal of resetting current circuit 3, and the input terminal of multiplexer 4 is
It is multiple, be separately connected the output end of the output end and D/A converter 5 of voltage follower 6, multiplexer 4 also with logic control
Unit 7 processed connects and receives the control of logic control element 7, for electric to resetting current according to the control of logic control element 7
(shutdown voltage is generated by voltage follower 6, and conducting voltage is produced by D/A converter 5 for the output of road 3 shutdown voltage or conducting voltage
It is raw)；
The input terminal of voltage follower 6 is connected to the input terminal of Power Capacity parting weak current measuring circuit 2, voltage follow
One input terminal of the output end connection multiplexer 4 of device 6, voltage follower 6 can replicate the voltage of weak current 1 to be measured
Shutdown voltage as resetting current circuit 3 (resetting current circuit 3 is delivered to by voltage is turned off by multiplexer 4)；
Another input terminal of the output end connection multiplexer 4 of D/A converter 5, D/A converter 5 can be to reset
Conducting voltage (is delivered to reset by the conducting voltage that current circuit 3 provides polarity and is sized to adjust by multiplexer 4
Current circuit 3), D/A converter 5 also connect with logic control element 7 and receives the control of logic control element 7, is used for basis
The control of logic control element 7 provides conducting voltage, and adjusts the polarity and size of conducting voltage；
When multiplexer 4 exports shutdown voltage, Power Capacity parting weak current measures when resetting current circuit 3 turns off
Circuit 2 is treated micrometer weak current 1 and is measured；When multiplexer 4 exports conducting voltage, resetting current circuit 3 is connected, and
Resetting current is exported to Power Capacity parting weak current measuring circuit 2.
The circuit board of low-leakage current restorer uses high insulating property plank, plank to include at least ceramic wafer.
Protection ring, protection ring are set around cabling on the output end of resetting current circuit 3 for exporting resetting current
For the shutdown voltage exported using voltage follower 6 as clamping voltag, protection ring does windowing turmeric process, and output resets electricity
Gap between the cabling of stream and the cabling of protection ring is 15mil.
Potential difference between the shutdown voltage provided of voltage follower 6 and the voltage of weak current to be measured 1 is less than 10 μ V.
When the selection of logic control element 7 exports conducting voltage by D/A converter 5, the reset of the output of resetting current circuit 3
Electric current is A grades of resetting currents of μ, the polarity and size of the conducting voltage that the polarity and size of resetting current are exported by D/A converter 5
It determines.
The resetting current circuit that resetting current circuit 3, voltage follower 6 are formed is arranged in metal shielding box, and leans on
Nearly Power Capacity parting weak current measuring circuit 2.
Resetting current circuit 3 includes the resistance being connected in parallel between the input terminal and output end of resetting current circuit 3 (see Fig. 4)
R1 and resistance R2；Resistance R1 connects a diode D2, diode D2 be located at resistance R1 and resetting current circuit 3 input terminal it
Between, resistance R1 is located at the positive side of diode D2；Resistance R2 connects a diode D1, and diode D1 is located at resistance R2 and answers
Between the input terminal of position current circuit 3, resistance R2 is located at the cathode side of diode D1；When resetting current circuit 3 is connected, electricity
Resistance R1, resistance R2 prevent resetting current excessive as the current-limiting resistance of resetting current circuit 3；When resetting current circuit 3 turns off,
Resistance R1, resistance R2 as the divider resistance of resetting current circuit 3 reduce diode terminal voltage (diode include diode D1 and
Diode D2)；
Resistance R1, resistance R2 are metalfilmresistor, and resistance value is 1M Ω；
Diode D1, diode D2 are that (diode D1, diode D2 are also by low reverse-bias leakage current diode PAD1
It can be replaced with the JFET types of same type and MOS type field-effect tube, such as PN4117A)；
The circuit being made of resistance R1, diode D2 and the circuit being made of resistance R2, diode D1 are respectively used to D/A and turn
The resetting current for the opposed polarity that parallel operation 5 exports；
The resetting current size I that resetting current circuit 3 exportsResetBy formula VDAC-VDiode/ R is obtained, wherein VDACFor D/A
The conducting voltage that converter 5 exports, VDiodeVoltage (about 0.7V), R are when being connected for diode (i.e. diode D1, diode D2)
Current-limiting resistance resistance value (be exactly resistance R1 and resistance R2 as current-limiting resistance when resistance value).
Voltage follower 6 (see U1 in Fig. 3) uses JFET grades of ultralow bias current Ib, low maladjustment voltage VosAmplifier
(in specific embodiment of the present invention the amplifier of voltage follower 6 use LMC6001AIN, can also be used lmp7721,
The close model of other indexs such as LMC6042AIN substitutes), amplifier is configured to positive follower, ultralow bias current make voltage with
Influence with device 6 to Power Capacity parting weak current measuring circuit 2 can be ignored.The pin 4 of amplifier LMC6001AIN and draw
Foot 7 connects power supply respectively, and pin 3 is normal phase input end, the input with (in Fig. 2) Power Capacity parting weak current measuring circuit 2
End connection (weak current 1 to be measured i.e. in connection figure 2), pin 2 are that reverse input end is connected to output end and company with pin 6
Being connected to multiplexer 4, (model of multiplexer 4 is MAX4518, amplifier in specific embodiment of the present invention
The output end of LMC6001AIN is specifically the pin 11 for connecting MAX4518, sees Fig. 6).
D/A converter 5 is controlled by logic control element 7, and the absolute value for the conducting voltage that D/A converter 5 exports is not less than
1V, so that the diode current flow in resetting current circuit 3, D/A converter 5 uses micro-control in utility model specific embodiment
Device stm32f103rct chips processed, the output end (i.e. the pin PB4 of microcontroller stm32f103rct) of D/A converter 5 is respectively
The output buffer being made of amplifier U2A and the sign-changing amplifier in proportion being configured to by amplifier U2B are connected to (see figure
5), to the identical voltage signal of the opposite size of output polarity, the output of output buffer is connected to MAX4518, and (i.e. multichannel is answered
With device 4) pin 4, the output of sign-changing amplifier is connected to the pin 5 of MAX4518 (see Fig. 6).D/A converter 5 is wanted without special
It asks, DAC module is carried using the piece of microcontroller stm32f103rct chips, other universal models also can be selected and replace.Amplifier
The model of U2A and amplifier U2B are OPA2277U；Resistance R3, resistance R4 use metalfilmresistor, and resistance value is 10k.
Multiplexer 4 (i.e. U3 in Fig. 6) uses the multiplexer of model MAX4518ESD, analog power to draw
Foot 3 and pin 12 connect ± 5V low noise power supplies, and pin 2 connects+3.3V high level, and pin 4 connects the positive polarity voltage of D/A converter 5,
Pin 5 connects the reverse voltage of D/A converter 5, and pin 11 connects the output of voltage follower 6 as shutdown voltage, and pin 10 connects zero
Current potential is shown in Fig. 6.
Logic control element 7 is supplied using the 32bit microcontrollers (MCU) of model stm32f103rct using+3.3V
Electricity communicates and is arranged output current potential by SPI2 buses with the completion of D/A converter 5, PC1 and PC2 pins are separately connected multichannel
The pin 1 and pin 14 of multiplexer 4 (U3 in Fig. 6), logic control element 7 select the output logic state of pin PC1 and PC2
To realize the different outputs of multiplexer；
Logic control element 7 use rs232 communication interfaces, can by host computer send instruction arrangement reset size of current and
Restorer state；
Logic controller 7 configures multiplexer 4 according to specific requirements and selects varying voltage signal as output to reset
Current circuit 3 realizes the shutdown or conducting of resetting current circuit 3, to meet Power Capacity parting weak current measuring circuit 2 not
Same demand.
When PC1 and PC2 the output low level of logic control element 7, the output of multiplexer 4 is positive polarity voltage, at this time
The diode D1 conductings of resetting current circuit 3,3 output cathode resetting current of resetting current circuit；Logic control element 7
When PC1 exports low level, PC2 output high level, the output of multiplexer 4 is reverse voltage, at this time resetting current circuit 3
Diode D2 conductings, 3 output negative pole resetting current of resetting current circuit；When the PC1 outputs of logic control element 7 are high electricity
When flat, PC2 outputs are low level, the output of multiplexer 4 is that weak current inputs terminal potential (the i.e. output of voltage follower 6
Turn off voltage), the diode D1 and diode D2 of resetting current circuit 3 are turned off, no current output, the faint electricity of Power Capacity parting
Flow measurement circuitry 2 can treat micrometer weak current 1 and carry out current measurement.
When the low-leakage current restorer for Power Capacity parting weak current measuring circuit is off state, i.e., multichannel is multiple
With the current potential that the output of device 4 is voltage follower 6, the voltage difference at the diode both ends of resetting current circuit 3 is far smaller than diode
The threshold voltage of conducting, diode cut-off.Series circuit is (i.e. by resistance R1, the concatenated circuits of diode D2 and by resistance R2, two
The concatenated circuits of pole pipe D1) potential difference at both ends mainly determines by the offset voltage of voltage follower 6, generally μ V (10-6V) grade
Not, high value resistor (resistance R1, resistance R2) is used as divider in series circuit.In this case, the electricity in diode PN sections
Stream is formed for the warm-up movement of hole-electron pair, and it is high that economize on electricity hinders the equivalent resistance resistance value to be formed of connecting with mega-ohms resistance.
1fA is no more than by the electric current that above-mentioned pressure difference and equivalent high value resistor are formed, to realize provided by the utility model be used for
The extremely low leakage current of the low-leakage current restorer of Power Capacity parting weak current measuring circuit.When faint for Power Capacity parting
When the low-leakage current restorer of current measurement circuit is conducting state, i.e. the output of multiplexer 4 is the output of D/A converter 5
Current potential, output current potential absolute value are more than 1V and make the diode current flow of resetting current circuit 3, and resetting current size is multiple equal to multichannel
The quotient being divided by with the difference of 4 output voltage of device and the diode voltage of resetting current circuit 3 and current-limiting resistance value, therefore resetting current is
μA(10-6A) grade, and the output voltage that can adjust D/A converter 5 according to demand realizes the adjusting of resetting current size.
Device described in the utility model is not limited to the embodiment described in specific implementation mode, those skilled in the art
Technical solution according to the present utility model obtains other embodiments, also belongs to the technological innovation scope of the utility model.
Claims (9)
1. a kind of low-leakage current restorer for Power Capacity parting weak current measuring circuit is connected to and treats micrometer weak current
(1) in the Power Capacity parting weak current measuring circuit (2) measured, it is characterized in that：Resetting current is connected including output end
The input terminal of circuit (3), input terminal connection voltage follower (6), D/A converter (5) output end multiplexer (4),
It is micro- that the output end of the resetting current circuit (3) and the input terminal of the voltage follower (6) are connected to the Power Capacity parting
The input terminal of Weak current measurement circuit (2)；The voltage follower (6) can replicate the voltage of the weak current to be measured (1)
As the shutdown voltage of the resetting current circuit (3), the D/A converter (5) can be that the resetting current circuit (3) carries
For polarity and it is sized to the conducting voltage adjusted；When the multiplexer (4) exports the shutdown voltage, the reset
Current circuit (3) turns off, and when the multiplexer (4) exports the conducting voltage, the resetting current circuit (3) is led
It is logical, and export resetting current to the Power Capacity parting weak current measuring circuit (2)；Further include multiple for controlling the multichannel
It is exported with device (4) the selection output shutdown voltage or the conducting voltage and the control D/A converter (5) described
The polarity of conducting voltage and the logic control element (7) of size.
2. being used for the low-leakage current restorer of Power Capacity parting weak current measuring circuit, feature as described in claim 1
It is：The circuit board of the low-leakage current restorer uses high insulating property plank, the plank to include at least ceramic wafer.
3. being used for the low-leakage current restorer of Power Capacity parting weak current measuring circuit, feature as described in claim 1
It is：Protection ring is set around cabling on the output end of the resetting current circuit (3) for exporting the resetting current, institute
Protection ring is stated using the shutdown voltage of the voltage follower (6) output as clamping voltag, the protection ring opens a window
Turmeric process, it is 15mil to export the gap between the cabling of the resetting current and the cabling of the protection ring.
4. being used for the low-leakage current restorer of Power Capacity parting weak current measuring circuit, feature as described in claim 1
It is：Potential difference between the shutdown voltage and the voltage of the weak current to be measured (1) that the voltage follower (6) provides
Less than 10 μ V.
5. being used for the low-leakage current restorer of Power Capacity parting weak current measuring circuit, feature as described in claim 1
It is：When the logic control element (7) selection exports the conducting voltage by the D/A converter (5), the resetting current
The resetting current of circuit (3) output is A grades of resetting currents of μ, and the polarity and size of the resetting current are converted by the D/A
The polarity and size of the conducting voltage of device (5) output determine.
6. being used for the low-leakage current restorer of Power Capacity parting weak current measuring circuit, feature as claimed in claim 5
It is：
The resetting current circuit (3) includes the electricity being connected in parallel between the input terminal and output end of the resetting current circuit (3)
Hinder R1 and resistance R2；The resistance R1 series connection one diode D2, the diode D2 are located at the resistance R1 and the input
Between end, the resistance R1 is located at the positive side of the diode D2；The resistance R2 connects a diode D1, and described two
For pole pipe D1 between the resistance R2 and the input terminal, the resistance R2 is located at the cathode side of the diode D1, institute
Stating current-limiting resistance when resistance R1, resistance R2 are connected as the resetting current circuit (3) prevents the resetting current excessive,
Divider resistance when being turned off as the resetting current circuit (3) reduces the diode terminal voltage；
The resistance R1, resistance R2 are metalfilmresistor, and resistance value is 1M Ω；
The diode D1, diode D2 are low reverse-bias leakage current diode PAD1；
The circuit being made of the resistance R1, diode D2 and the circuit being made of the resistance R2, diode D1 are respectively used to
The resetting current of the opposed polarity of D/A converter (5) output；
The resetting current size I of resetting current circuit (3) outputResetBy formula (VDAC-VDiode)/R is obtained, wherein VDACFor
The conducting voltage of D/A converter (5) output, VDiodeVoltage when being connected for the diode D1, diode D2, R are
The resistance value of the current-limiting resistance.
7. being used for the low-leakage current restorer of Power Capacity parting weak current measuring circuit, feature as described in claim 1
It is：The absolute value of the conducting voltage of D/A converter (5) output is not less than 1V.
8. being used for the low-leakage current restorer of Power Capacity parting weak current measuring circuit, feature as described in claim 1
It is：The voltage follower (6) uses JFET grades of ultralow bias current Ib, low maladjustment voltage VosAmplifier, the amplifier
It is configured to positive follower.
9. being used for the low-leakage current restorer of Power Capacity parting weak current measuring circuit, feature as described in claim 1
It is：The resetting current circuit that the resetting current circuit (3), voltage follower (6) are formed is arranged in metal shielding box, and
Close to the Power Capacity parting weak current measuring circuit (2).
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN201721800538.6U CN207689555U (en) | 2017-12-21 | 2017-12-21 | A kind of low-leakage current restorer for Power Capacity parting weak current measuring circuit |
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| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN201721800538.6U CN207689555U (en) | 2017-12-21 | 2017-12-21 | A kind of low-leakage current restorer for Power Capacity parting weak current measuring circuit |
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| CN207689555U true CN207689555U (en) | 2018-08-03 |
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| CN201721800538.6U Withdrawn - After Issue CN207689555U (en) | 2017-12-21 | 2017-12-21 | A kind of low-leakage current restorer for Power Capacity parting weak current measuring circuit |
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Cited By (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN108037341A (en) * | 2017-12-21 | 2018-05-15 | 中国原子能科学研究院 | A kind of low-leakage current restorer for Power Capacity parting weak current measuring circuit |
| CN111766458A (en) * | 2020-06-03 | 2020-10-13 | 国网山东省电力公司莱芜供电公司 | Current integration-based method for measuring accumulated charges of insulating materials of direct-current high-voltage equipment |
-
2017
- 2017-12-21 CN CN201721800538.6U patent/CN207689555U/en not_active Withdrawn - After Issue
Cited By (3)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN108037341A (en) * | 2017-12-21 | 2018-05-15 | 中国原子能科学研究院 | A kind of low-leakage current restorer for Power Capacity parting weak current measuring circuit |
| CN108037341B (en) * | 2017-12-21 | 2024-05-10 | 中国原子能科学研究院 | Low leakage current reset device for capacitance integral weak current measurement circuit |
| CN111766458A (en) * | 2020-06-03 | 2020-10-13 | 国网山东省电力公司莱芜供电公司 | Current integration-based method for measuring accumulated charges of insulating materials of direct-current high-voltage equipment |
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