CN113376441B - System and method for measuring parasitic inductance parameters of thin film capacitor - Google Patents
System and method for measuring parasitic inductance parameters of thin film capacitor Download PDFInfo
- Publication number
- CN113376441B CN113376441B CN202110471829.XA CN202110471829A CN113376441B CN 113376441 B CN113376441 B CN 113376441B CN 202110471829 A CN202110471829 A CN 202110471829A CN 113376441 B CN113376441 B CN 113376441B
- Authority
- CN
- China
- Prior art keywords
- capacitor
- thin film
- module
- tested
- circuit module
- Prior art date
- Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
- Active
Links
Images
Classifications
-
- G—PHYSICS
- G01—MEASURING; TESTING
- G01R—MEASURING ELECTRIC VARIABLES; MEASURING MAGNETIC VARIABLES
- G01R27/00—Arrangements for measuring resistance, reactance, impedance, or electric characteristics derived therefrom
- G01R27/02—Measuring real or complex resistance, reactance, impedance, or other two-pole characteristics derived therefrom, e.g. time constant
- G01R27/26—Measuring inductance or capacitance; Measuring quality factor, e.g. by using the resonance method; Measuring loss factor; Measuring dielectric constants ; Measuring impedance or related variables
- G01R27/2611—Measuring inductance
Landscapes
- Physics & Mathematics (AREA)
- General Physics & Mathematics (AREA)
- Measurement Of Resistance Or Impedance (AREA)
Abstract
The invention discloses a system and a method for measuring parasitic inductance parameters of a thin film capacitor, and the system and the method comprise a module to be measured, a capacitor charging and discharging main circuit module, a driving circuit module and a data acquisition and processing module, wherein the module to be measured comprises the thin film capacitor to be measured and an additional thin film small capacitor, the thin film capacitor to be measured and the additional thin film small capacitor are connected in series, the capacitor charging and discharging main circuit comprises one or more switching tubes, the driving circuit module can control the charging or discharging of the module to be measured through the capacitor charging and discharging main circuit, and the data acquisition and processing module can acquire and process current data. The system and the method for measuring the parasitic inductance parameter of the thin film capacitor can realize the rapid measurement of the parasitic inductance parameter of the thin film capacitor.
Description
Technical Field
The invention relates to the field of parasitic parameter measurement, in particular to a system for measuring parasitic inductance parameters of a thin film capacitor.
Background
In an actual circuit, a capacitance component has various distribution parameters, wherein parasitic inductances have the greatest influence on the characteristics of the capacitance, and the inductance characteristics of the parasitic inductances cause the capacitance to have certain limitations in use. In the switching circuit, the parasitic inductance of the commutation loop plays a very important role. Depending on the inductance of the parasitic inductance and the rate of change of current di/dt, the device is subjected to additional voltage stress during the switching state, and extreme conditions may cause damage to the device. The parasitic inductance of the direct current bus capacitor in the current conversion loop is one of the influencing factors, so that the parasitic inductance of the capacitor can be measured, and a capacitor component can be selected more reasonably when the capacitor is used. Because the inductance of the parasitic inductance of the capacitor is very small, generally in the nH level, most of the LCR bridges cannot measure the parasitic inductance of the capacitor. The method for measuring the parasitic inductance parameters of the capacitor mainly utilizes the capacitor self-resonance principle to measure, but because the capacitance value of the capacitor and the inductance value of the parasitic inductance to be measured are not determined, the measuring equipment needs to provide a very large voltage frequency range, and the measuring process needs to detect and acquire the corresponding frequency when the capacitor element generates self-resonance, which is not beneficial to quick and accurate measurement.
Disclosure of Invention
In order to solve the problems in the prior art, the invention provides a system for measuring the parasitic inductance parameter of a film capacitor, which adopts the following technical scheme:
in one aspect, the present invention provides a system for measuring parasitic inductance parameters of a thin film capacitor, including:
the module to be tested comprises a thin film capacitor to be tested and an additional thin film small capacitor, and the thin film capacitor to be tested and the additional thin film small capacitor are connected in series;
the capacitor charging and discharging main circuit module is connected with the module to be tested and comprises one or more switching tubes;
the driving circuit module is connected with the capacitor charging and discharging main circuit module and can send a driving signal to control the switching tube to be switched on or off so as to control the module to be tested to be charged or discharged;
the data acquisition and processing module is respectively connected with the capacitor charging and discharging main circuit module and the driving circuit module, can control the driving circuit module to send signals, and can acquire current data of the module to be detected, process the current data and obtain a processing result.
Further, the data collecting and processing module comprises:
the acquisition circuit is connected with the capacitor charging and discharging main circuit module and is used for acquiring current data of the module to be tested;
the data processing unit is connected with the acquisition circuit and processes the current data to obtain a processing result;
the signal control unit is electrically connected with the driving circuit module and can control the driving circuit module to send out signals.
Further, the switch tube is a MOSFET switch tube.
Further, the driving circuit module includes:
the reverse Schmitt trigger is connected with the signal control unit and can convert the normally high state signal sent by the signal control unit into a normally low state signal, or the reverse Schmitt trigger can convert the normally low state signal sent by the signal control unit into a normally high state signal;
the driver is connected with the capacitor charging and discharging main circuit module, the driver is connected with the reverse Schmitt trigger, and the driver can send out corresponding driving signals based on normally low or normally high state signals.
Furthermore, a current hall sensor is arranged in the acquisition circuit, and the acquisition circuit acquires current through the current hall sensor arranged in the acquisition circuit.
Further, the capacitance of the small capacitor of the additional film is 0-500 muF.
Further, the capacitance of the additional thin film small capacitor is 3.3-325 muF.
Furthermore, the signal control unit and the data processing unit are both realized by an FPGA. The FPGA is used as a central processing unit, so that the operation precision is greatly improved on the premise of low cost.
On the other hand, the invention also provides a method for measuring the parasitic inductance parameter of the film capacitor, which comprises the following steps:
s1, connecting a film capacitor to be tested and an additional film small capacitor in series, and charging the film capacitor to be tested and the additional film small capacitor by using a direct current source;
s2, disconnecting the direct current source to enable the film capacitor to be tested to discharge through the conducted switch tube loop, and collecting and recording current data flowing through the film capacitor to be tested before and after discharging;
s3, connecting two identical thin film capacitors to be tested with the extra thin film small capacitor in series, charging by using a direct current source, and repeating the step S2;
s4, substituting the data in the step S2 and the step S3 into formulas respectively
And obtaining two equations, combining the two equations, and solving to obtain the inductance value of the parasitic inductance of the thin film capacitor to be measured. Wherein, T is the period of capacitor oscillation discharge, L is the inductance value of the loop, and C is the capacitance value of the loop.
Further, in step S2, nonlinear curve fitting is performed on the acquired current data, so as to obtain the period T of the capacitive oscillation discharge.
The technical scheme provided by the invention has the following beneficial effects:
a) The measuring method based on the capacitance oscillation discharge can realize the rapid measurement of the parasitic inductance parameters of the thin film capacitor, and solve the problems of long time consumption, low precision and the like of the traditional measuring method;
b) The FPGA is used as a central processing unit, so that the ultrahigh operation speed can be achieved;
c) The hardware scheme is simple and easy to realize.
Drawings
In order to more clearly illustrate the technical solutions in the embodiments of the present invention, the drawings required to be used in the description of the embodiments are briefly introduced below, and it is obvious that the drawings in the description below are only some embodiments of the present invention, and it is obvious for those skilled in the art that other drawings can be obtained according to the drawings without creative efforts.
Fig. 1 is a schematic diagram of a system for measuring parasitic inductance parameters of a thin film capacitor according to an embodiment of the present invention;
fig. 2 is a schematic circuit connection diagram of the method for measuring parasitic inductance parameters of a thin film capacitor according to the embodiment of the present invention in step S2;
fig. 3 is a schematic circuit connection diagram of the method for measuring parasitic inductance parameter of a thin film capacitor according to the embodiment of the present invention in step S3;
fig. 4 is a schematic flowchart of a method for measuring a parasitic inductance parameter of a thin film capacitor according to an embodiment of the present invention;
fig. 5 is a schematic diagram of a test result of the capacitance charge and discharge measurement module according to the embodiment of the present invention.
Detailed Description
In order to make those skilled in the art better understand the technical solutions of the present invention, the technical solutions in the embodiments of the present invention will be clearly and completely described below with reference to the drawings in the embodiments of the present invention, and it is obvious that the described embodiments are only a part of the embodiments of the present invention, and not all of the embodiments. All other embodiments, which can be derived by a person skilled in the art from the embodiments given herein without making any creative effort, shall fall within the protection scope of the present invention.
It should be noted that the terms "first," "second," and the like in the description and claims of the present invention and in the drawings described above are used for distinguishing between similar elements and not necessarily for describing a particular sequential or chronological order. It is to be understood that the data so used is interchangeable under appropriate circumstances such that the embodiments of the invention described herein are capable of operation in sequences other than those illustrated or described herein. Furthermore, the terms "comprises," "comprising," and "having," and any variations thereof, are intended to cover a non-exclusive inclusion, such that a process, method, apparatus, article, or device that comprises a list of steps or elements is not necessarily limited to those steps or elements expressly listed, but may include other steps or elements not expressly listed or inherent to such process, method, article, or device.
In an embodiment of the present invention, referring to fig. 1 to 3, there is provided a system for measuring a parasitic inductance parameter of a thin film capacitor, including:
the module to be tested comprises a thin film capacitor to be tested and an additional thin film small capacitor, and the thin film capacitor to be tested and the additional thin film small capacitor are connected in series;
the capacitor charging and discharging main circuit module is connected with the module to be tested and comprises one or more switching tubes;
the driving circuit module is connected with the capacitor charging and discharging main circuit module and can send a driving signal to control the switching tube to be switched on or off so as to control the module to be tested to be charged or discharged;
the data acquisition and processing module is respectively connected with the capacitor charging and discharging main circuit module and the driving circuit module, can control the driving circuit module to send signals, and can acquire current data of the module to be detected, process the current data and obtain a processing result.
In one embodiment of the present invention, the data collecting and processing module comprises:
the acquisition circuit is connected with the capacitor charging and discharging main circuit module and is used for acquiring current data of the module to be detected;
the data processing unit is connected with the acquisition circuit and processes the current data to obtain a processing result;
and the signal control unit is electrically connected with the driving circuit module and can control the driving circuit module to send out signals.
In one embodiment of the present invention, the switch tube is a MOSFET switch tube.
In one embodiment of the present invention, the driving circuit module includes:
the reverse Schmitt trigger is connected with the signal control unit and can convert the normally high state signal sent by the signal control unit into a normally low state signal, or the reverse Schmitt trigger can convert the normally low state signal sent by the signal control unit into a normally high state signal;
the driver is connected with the capacitor charging and discharging main circuit module, the driver is connected with the reverse Schmitt trigger, and the driver can send out corresponding driving signals based on normally low or normally high state signals.
In one embodiment of the present invention, a current hall sensor is disposed in the acquisition circuit, and the acquisition circuit acquires current through the current hall sensor disposed in the acquisition circuit.
In one embodiment of the invention, the capacitance of the additional thin film small capacitor is 0-500 muF.
In one embodiment of the invention, the capacitance of the additional thin film small capacitor is 3.3-325 μ F.
In one embodiment of the present invention, the signal control unit and the data processing unit are both implemented by an FPGA.
Referring to fig. 4, in an embodiment of the present invention, there is also provided a method for measuring a parasitic inductance parameter of a thin film capacitor, the method including the steps of:
s1, connecting a film capacitor to be tested and an additional film small capacitor in series, and charging the film capacitor to be tested and the additional film small capacitor by using a direct current source;
s2, disconnecting the direct current source to enable the film capacitor to be tested to discharge through the conducted switch tube loop, and collecting and recording current data flowing through the film capacitor to be tested before and after discharging;
s3, connecting two identical thin film capacitors to be tested and the additional thin film small capacitor in series, charging by using a direct current source, and repeating the step S2;
s4, substituting the data in the step S2 and the step S3 into formulas respectively
Two equations are obtained, and the two equations are simultaneously established to solve the inductance value of the parasitic inductance of the film capacitor to be measured.
In an embodiment of the present invention, in the step S2, a nonlinear curve fitting is performed on the acquired current data, so as to obtain the period T of the capacitive oscillating discharge.
In the measuring method, the processes of charging, disconnecting the direct current source and the like can be realized by a switch tube in the measuring system in the embodiment of the invention, and the signal control unit is used for controlling the switch tube according to a preset program to realize the process; the process of fitting the linear curve and solving the simultaneous equations can be realized by the data acquisition and processing module in the embodiment of the invention.
The invention will now be described in detail by way of a preferred embodiment with reference to the accompanying drawings.
The present embodiment uses an FPGA as a central processing unit.
Referring to fig. 1, a system for rapidly measuring a parasitic inductance parameter of a thin film capacitor, comprises:
the thin film capacitor to be measured is connected with the capacitance charge-discharge measurement module and the additional thin film small capacitor;
the extra thin film small capacitor is connected with the capacitance charge-discharge measurement module and the thin film capacitor to be measured;
the capacitance charging and discharging measurement module is respectively connected with the one/two thin film capacitors to be measured, the additional thin film small capacitor and the data acquisition and processing module and is used for charging and discharging the thin film capacitors;
and the data acquisition and processing module is connected with the capacitance charging and discharging measurement module and is used for sending a control signal, acquiring the current flowing through the thin film capacitor before and after the thin film capacitor to be measured discharges and processing the acquired current data.
The capacitance charge-discharge measurement module comprises: the driving circuit and the capacitor charging and discharging main circuit. The driving circuit is connected with the capacitor charging and discharging main circuit and is used for sending a driving signal to drive a switching tube in the capacitor charging and discharging main circuit to be switched on or switched off; the capacitor charging and discharging main circuit is connected with one/two thin film capacitors to be tested and the additional thin film small capacitor and is used for charging and discharging the thin film capacitors.
The measuring process of the parasitic inductance parameter of the film capacitor comprises two steps: a thin film capacitor to be tested is connected in series with an additional thin film small capacitor for testing; two identical thin film capacitors to be tested are connected in series with an additional thin film small capacitor for testing. Preferably, the extra small film capacitance of this embodiment is a film capacitance of 3.3uF, which is determined by the specific experimental platform of this embodiment. Through experimental tests, the total parasitic inductance of the thin film capacitor discharge circuit of the embodiment is about 80m Ω, and the total parasitic inductance is about 500nH
Obtaining C < 325uF,
therefore, an extra film capacitor of 3.3uF can be selected to satisfy the requirement. The test process can be divided into two phases: the charging stage and the discharging stage are shown in fig. 2, which is a circuit diagram of the capacitor charging and discharging main circuit connected with a film capacitor to be measured and an extra film small capacitor of 3.3 uF. R is a current limiting resistor, VS 1 And VS 2 Upper and lower arms, R, of the MOSFET half-bridge modules, respectively S 、L S Respectively the parasitic resistance and the parasitic inductance, R, of the thin film capacitor to be measured 1 、L 1 The total parasitic resistance and the total parasitic inductance of the loop are respectively. In the charging phase, the upper arm VS 1 In a conducting state, a lower bridge arm VS 2 Is in an off state when the DC source V is DC And charging the film capacitor to be tested and the small extra film capacitor. In the discharge phase, the DC source V is disconnected DC Upper bridge arm VS 1 In an off state, a lower bridge arm VS 2 Is in a conducting state, and the film capacitor passes through a lower bridge arm VS 2 The circuit is discharged. FIG. 3 shows the test results of the measurement module for measuring the charge and discharge of capacitance, the thin film capacitor to be measured, the small capacitance of the additional thin film and the switch tube VS 2 Forming a discharge loop, the following equation holds for the discharge process.
Referring to fig. 3, a circuit diagram of a capacitor charging and discharging main circuit connected with two identical thin film capacitors to be tested and an additional thin film small capacitor of 3.3uF shows that the following equation holds in the discharging process when the thin film capacitor is subjected to the charging and discharging experiment in the same way.
The data collecting and processing module 400 includes: a signal control unit 401, an acquisition circuit 402 and a data processing unit 403. In this embodiment, the signal control unit and the data processing unit are both implemented in an FPGA. The signal control unit is used for sending a control signal to control the switch tube to be switched on or switched off; the acquisition circuit is connected with the capacitor charging and discharging main circuit and is used for acquiring current flowing through the thin film capacitor to be detected; the data processing unit is used for processing the acquired current data and then calculating the inductance value of the parasitic inductance of the film capacitor according to the formula.
As shown in fig. 4, the data processing unit processes the current data flowing through the thin film capacitor to be measured by: carrying out nonlinear curve fitting on current data flowing through the thin film capacitor to be measured so as to obtain the period of capacitance oscillation discharge; then, the known data is substituted into equations (1) and (2), and the parasitic inductance parameter L of the thin film capacitor to be measured can be obtained by combining equations (1) and (2) S 。
In summary, the present invention is a system for measuring parasitic inductance parameters of a thin film capacitor based on capacitive oscillating discharge, which can achieve fast measurement of parasitic inductance parameters of the thin film capacitor.
The above description is only for the purpose of illustrating the preferred embodiments of the present invention and is not to be construed as limiting the invention, and any modifications, equivalents, improvements and the like that fall within the spirit and principle of the present invention are intended to be included therein.
Claims (10)
1. A system for measuring parasitic inductance parameters of a thin film capacitor, comprising:
the module to be tested comprises a thin film capacitor to be tested and an additional thin film small capacitor, and the thin film capacitor to be tested and the additional thin film small capacitor are connected in series;
the capacitor charging and discharging main circuit module is connected with the module to be tested and comprises one or more switching tubes;
the driving circuit module is connected with the capacitor charging and discharging main circuit module and can send a driving signal to control the switching tube to be switched on or off so as to control the module to be tested to be charged or discharged;
the data acquisition and processing module is respectively connected with the capacitor charging and discharging main circuit module and the driving circuit module, can control the driving circuit module to send signals, and can acquire current data of the module to be detected, process the current data and obtain a processing result.
2. The measurement system of claim 1, wherein the data acquisition and processing module comprises:
the acquisition circuit is connected with the capacitor charging and discharging main circuit module and is used for acquiring current data of the module to be detected;
the data processing unit is connected with the acquisition circuit and processes the current data to obtain a processing result;
the signal control unit is electrically connected with the driving circuit module and can control the driving circuit module to send out signals.
3. The measurement system of claim 1, wherein the switching tube is a MOSFET switching tube.
4. The measurement system of claim 2, wherein the drive circuit module comprises:
the reverse Schmitt trigger is connected with the signal control unit and can convert the normally high state signal sent by the signal control unit into a normally low state signal, or the reverse Schmitt trigger can convert the normally low state signal sent by the signal control unit into a normally high state signal;
the driver is connected with the capacitor charging and discharging main circuit module, the driver is connected with the reverse Schmitt trigger, and the driver can send out corresponding driving signals based on normally low or normally high state signals.
5. The measurement system of claim 2, wherein the collection circuit has a current hall sensor disposed therein, the collection circuit collecting current through the current hall sensor disposed therein.
6. The measurement system of claim 1, wherein the additional thin film small capacitor has a capacitance of 0 to 500 μ F.
7. The measurement system of claim 6, wherein the additional thin film small capacitor has a capacitance of 3.3 to 325 μ F.
8. The measurement system of claim 2, wherein the signal control unit and the data processing unit are both implemented by FPGAs.
9. A method for measuring parasitic inductance parameters of a film capacitor is characterized by comprising the following steps:
s1, connecting a film capacitor to be tested and an additional film small capacitor in series, and charging the film capacitor to be tested and the additional film small capacitor by using a direct current source;
s2, disconnecting the direct current source to enable the thin film capacitor to be tested to discharge through the conducted switch tube loop, and collecting and recording current data flowing through the thin film capacitor to be tested before and after discharging;
s3, connecting two identical thin film capacitors to be tested with the extra thin film small capacitor in series, charging by using a direct current source, and repeating the step S2;
s4, substituting the data in the step S2 and the step S3 into formulas respectively
And obtaining two equations, combining the two equations, and solving to obtain the inductance value of the parasitic inductance of the thin film capacitor to be measured, wherein T is the period of capacitor oscillation discharge, L is the inductance value of the loop, and C is the capacitance value of the loop.
10. The measurement method according to claim 9, wherein in the step S2, the acquired current data is subjected to nonlinear curve fitting to find the period T of the oscillating discharge of the capacitance.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN202110471829.XA CN113376441B (en) | 2021-04-29 | 2021-04-29 | System and method for measuring parasitic inductance parameters of thin film capacitor |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN202110471829.XA CN113376441B (en) | 2021-04-29 | 2021-04-29 | System and method for measuring parasitic inductance parameters of thin film capacitor |
Publications (2)
| Publication Number | Publication Date |
|---|---|
| CN113376441A CN113376441A (en) | 2021-09-10 |
| CN113376441B true CN113376441B (en) | 2022-11-18 |
Family
ID=77570730
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CN202110471829.XA Active CN113376441B (en) | 2021-04-29 | 2021-04-29 | System and method for measuring parasitic inductance parameters of thin film capacitor |
Country Status (1)
| Country | Link |
|---|---|
| CN (1) | CN113376441B (en) |
Families Citing this family (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN113030584A (en) * | 2021-03-10 | 2021-06-25 | 上海海事大学 | System and method for measuring parasitic inductance parameter of capacitor |
Family Cites Families (6)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN102495294B (en) * | 2011-11-30 | 2014-11-26 | 台达电子企业管理（上海）有限公司 | System and method for testing parasitic inductance |
| CN107102211B (en) * | 2016-12-31 | 2023-11-07 | 中国矿业大学 | Device and method for measuring stray inductance inside IGBT module |
| CN110850208B (en) * | 2019-11-15 | 2020-08-21 | 浙江大学 | Laminated busbar stray parameter extraction method based on SiC MOSFET frequency characteristics |
| CN212514786U (en) * | 2020-04-24 | 2021-02-09 | 吉林大学 | Inductor and transformer parasitic capacitance test system |
| CN111929506B (en) * | 2020-07-14 | 2021-07-20 | 同济大学 | Method for extracting stray inductance parameters of converter |
| CN112433097B (en) * | 2020-11-06 | 2021-09-28 | 浙江大学 | Film capacitor ESL extraction method based on switch transient frequency information |
-
2021
- 2021-04-29 CN CN202110471829.XA patent/CN113376441B/en active Active
Also Published As
| Publication number | Publication date |
|---|---|
| CN113376441A (en) | 2021-09-10 |
Similar Documents
| Publication | Publication Date | Title |
|---|---|---|
| CN103430039B (en) | State of insulation detecting device | |
| CN106501618B (en) | Capacitor's capacity measuring circuit | |
| CN106645981B (en) | Capacitor's capacity measuring circuit | |
| CN104714153B (en) | winding test device | |
| JP2013205082A (en) | Insulation state detector | |
| CN105244848B (en) | Over-voltage protection method and circuit | |
| WO2008147694A1 (en) | Capacitive measurements with fast recovery current return | |
| CN111919129B (en) | Apparatus and method for monitoring multi-chip power | |
| CN113376441B (en) | System and method for measuring parasitic inductance parameters of thin film capacitor | |
| CN104020357A (en) | Capacitance test circuit and test method under DC bias condition | |
| JPH07151792A (en) | Method and device for automatically detecting and measuring amount of measurement and multimeter | |
| CN104459338B (en) | Capacitor capacitance value measuring device and measuring method | |
| CN112955758A (en) | Method for insulation resistance measurement in an inverter having a multipoint topology and inverter having a multipoint topology | |
| CN111308232A (en) | System and method for measuring stray parameters of current loop of high-power converter module | |
| CN108139447B (en) | Vehicle, device and method for determining battery voltage in multiple series battery strings | |
| CN109342827B (en) | Circuit and method for measuring capacitance value through capacitance alternating current charge and discharge | |
| CN112881809A (en) | System and method for measuring parasitic inductance parameters of thin film capacitor | |
| JP4659296B2 (en) | Method for measuring equivalent parallel resistance of power storage device | |
| CN211856709U (en) | Current detection circuit | |
| CN209820646U (en) | IGBT module temperature measurement circuit | |
| JPH09211041A (en) | Method and device for measuring equivalent series resistance of capacitive element | |
| CN210865578U (en) | Power consumption detection circuit of display panel | |
| CN113030584A (en) | System and method for measuring parasitic inductance parameter of capacitor | |
| RU2260190C1 (en) | Relaxation measuring device for parameters of cg-dipole | |
| CN109818328A (en) | A kind of switch power over-voltage protection circuit |
Legal Events
| Date | Code | Title | Description |
|---|---|---|---|
| PB01 | Publication | ||
| PB01 | Publication | ||
| SE01 | Entry into force of request for substantive examination | ||
| SE01 | Entry into force of request for substantive examination | ||
| GR01 | Patent grant | ||
| GR01 | Patent grant |