CN101871962A - Current detecting method and circuit - Google Patents
Current detecting method and circuit Download PDFInfo
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- CN101871962A CN101871962A CN 201010186716 CN201010186716A CN101871962A CN 101871962 A CN101871962 A CN 101871962A CN 201010186716 CN201010186716 CN 201010186716 CN 201010186716 A CN201010186716 A CN 201010186716A CN 101871962 A CN101871962 A CN 101871962A
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Abstract
The invention discloses a current detecting method and a circuit thereof for improving the detection precision. The method comprises the following steps of: acquiring a to-be-detected current; generating a standard current; and judging whether the to-be-detected current reaches a predetermined value according to the to-be-detected current and the standard current. The circuit comprises a to-be-detected current acquiring module for acquiring the to-be-detected current; a standard current generating module for generating a standard current; and a detecting module for judging whether the to-be-detected current reaches a predetermined value according to the to-be-detected current acquired by the to-be-detected current acquiring module and the standard current generated by the standard current generating module.
Description
Technical field
The present invention relates to integrated circuit fields, relate in particular to electric current detecting method and circuit.
Background technology
Current detection technology has very widely to be used, and all needs to detect the size that flows into and flow out electric current in many systems.For example current protection/current monitoring equipment, programmable current source, linearity/switched-mode power supply and need to be grasped charger goods battery electric quantity meter of inflow and outflow current ratio etc.Because a lot of the application is of portable form, so current detection circuit also must have the characteristic of small size, low-power consumption usually.
Fig. 1 is existing current detection circuit framework synoptic diagram, and Fig. 2 is the concrete structure synoptic diagram of existing current detection circuit, and with reference to figure 1 and Fig. 2, the principle of current detection circuit is usually:
Detect load current; When detecting load current and reach predetermined value, detected electric current is converted into voltage, and with this voltage input amplifier AMP1 two ends, behind amplifier, the triggering following circuit.
From Fig. 2, can draw:
V
+-V
-＝R
s *ISS
V
+/2＝V
amp +
Further can derive and obtain:
V
O＝V
+-V
-＝R
s *ISS
Above-mentioned detection scheme can be realized the detection of lower accuracy, but for high-precision requirement, because the resistors match degree requires high, input resistance Rs generally has bigger error amount, therefore may cause that circuit does not match very greatly, do not reach described predetermined value mistiming at electric current and be judged as and reach predetermined value, and then the triggering following circuit, cause a series of problems of entire circuit.
Summary of the invention
The invention provides electric current detecting method and circuit, to improve accuracy of detection.
Electric current detecting method provided by the invention comprises step: obtain the detection electric current; Generate reference current; According to described detection electric current and reference current, judge whether detect electric current reaches predetermined value.
Current detection circuit provided by the invention comprises: detect the electric current acquisition module, be used to obtain the detection electric current; The reference current generation module is used to generate reference current; Detection module is used for detection electric current that obtains based on detection electric current acquisition module and the reference current that generates based on the reference current generation module, detects the detection electric current and whether reaches predetermined value.
With only judge that based on detecting electric current its scheme that whether reaches predetermined value compares in the prior art, the solution of the present invention is by judging in conjunction with reference current and testing circuit whether detect electric current reaches predetermined value, and the precision of reference current is very high, therefore can improve the current precision of detection greatly.
Description of drawings
Fig. 1 is existing current detection circuit framework synoptic diagram;
Fig. 2 is the concrete structure synoptic diagram of existing current detection circuit;
Fig. 3 is an embodiment of the invention circuit frame synoptic diagram;
Fig. 4 is the concrete structure synoptic diagram of embodiment of the invention current detection circuit.
Embodiment
Because prior art only judges based on detecting electric current whether it reaches predetermined value, therefore precision is not high, the inventor proposes and can improve accuracy of detection like this by whether reaching predetermined value in conjunction with detecting electric current and high-precision reference current detection electric current.Based on this thinking, present embodiment provides following multiple electric current detecting method and circuit:
This detection method comprises step:
Step 1 is obtained the detection electric current;
Step 2 generates reference current;
Step 3 according to described detection electric current and reference current, judges whether detect electric current reaches predetermined value.
Wherein step 3 can have multiple implementation, reference current value for example is set equals predetermined value, judges whether detect current value equates with reference current value, if then reach, otherwise do not reach; Provide several implementations of step 3 below:
Mode one:
The current value that reference current is set equals described predetermined value;
Under the situation of the current value that equals reference current that detects electric current, judge the detection electric current and reach predetermined value, do not reach predetermined value otherwise judge.
Mode two:
Step a1 generates benchmark and merges electric current, and its current value equals described predetermined value and reference current value sum, and two branch currents of this benchmark merging electric current access, and wherein a branch current is for detecting electric current, and another branch current is a reference current;
Step a2 judges whether detect current value equals the poor of benchmark merging current value and reference current value, as if equating, then judge that detecting current value reaches predetermined value, does not reach otherwise judge.
Mode three:
Step b1 generates benchmark and splits electric current, and its current value equals the poor of described predetermined value and reference current value, and two branch currents of reference current access, and wherein a branch current is for detecting electric current, and another branch current is that benchmark splits electric current;
Step b2 judges whether detect electric current equals benchmark fractionation current value and reference current value sum, as if equating, then judge that detecting current value reaches predetermined value, does not reach otherwise judge.
By above-mentioned electric current detecting method, present embodiment utilizes reference current to realize current detecting, and its accuracy of detection is higher than the accuracy of detection of existing scheme.
Present embodiment gives current detection circuit in addition, to improve accuracy of detection.This circuit comprises:
Detect the electric current acquisition module, be used to obtain the detection electric current; The reference current generation module is used to generate reference current; Detection module is used for detection electric current that obtains based on detection electric current acquisition module and the reference current that generates based on the reference current generation module, detects the detection electric current and whether reaches predetermined value.
Wherein detection module can have following several formation scheme:
Scheme one, the current value of described reference current equals described predetermined value; And described detection module specifically comprises: detect electric current and receive submodule, be used for receiving the detection electric current; Reference current receives submodule, is used to receive reference current; Comparison sub-module is used for the benchmark electric current and detects electric current, if both current values are equal, determines that then detecting electric current reaches predetermined value, does not reach predetermined value otherwise determine to detect electric current.
Scheme two, described detection module, specifically comprise: benchmark merges electric current and generates submodule, be used to generate benchmark and merge electric current, its current value equals described predetermined value and reference current value sum, and this benchmark merges electric current and inserts two branch currents, and wherein a branch current is for detecting electric current, and another branch current is a reference current; First judges submodule, is used for judging whether detect current value equals the poor of benchmark merging current value and reference current value, as if equating, then judge that detecting current value reaches predetermined value, does not reach otherwise judge.
Scheme three, described detection module, specifically comprise: benchmark splits electric current and generates submodule, be used to generate benchmark and split electric current, its current value equals the poor of described predetermined value and reference current value, and reference current inserts two branch currents, and wherein a branch current is for detecting electric current, and another branch current is that benchmark splits electric current; Second judges submodule, is used for judging whether detect electric current equals benchmark fractionation current value and reference current value sum, as if equating, then judge that detecting current value reaches predetermined value, does not reach otherwise judge.
Provide a kind of circuit structure embodiment below and set forth such scheme, below supposition detects resistance and is fixed as Rs, and the detection electric current is ISS, and then detecting voltage is Rs*ISS, supposes that detecting magnitude of voltage is 100mv.
The thinking of present embodiment is: by the normalized current generative circuit of band-gap reference output, from the reference voltage module, draw a normal voltage, again this normal voltage being added in and detecting resistance makes on the identical Rs resistance, make the error relative insensitivity of circuit to detection resistance value, reach preferable performance, thereby can obtain the higher current detection circuit of precision, be highly susceptible to carrying out as required more high-precision expansion simultaneously, and the area that increases is also little.
Fig. 3 is the theory diagram of present embodiment, it mainly is the branch road of drawing by band-gap reference output of having introduced the right side, wherein, the 100mv voltage on right side is the normal voltage of directly exporting from the band-gap reference module, can guarantee the stable of magnitude of voltage, simultaneously the RS resistance on right side is that the detection resistance R S with the left side is at same process, equivalent environment is made down, guarantee that like this resistance mismatch reaches minimum, simultaneously, amplifier AMP1 and AMP2 inner structure basically identical, the amplifier on both sides compares for following AMP3 by the current-mirror structure output current simultaneously, left side amplifier output be to detect electric current, the output of right side amplifier be that normalized current compares usefulness, realize more current with high accuracy detection module of the original scheme of ratio like this.
Fig. 4 is present embodiment particular circuit configurations figure, the input on right side is that the accurate 100mv voltage of bandgap dividing potential drop is added on the RS resistance, this RS resistance is that RS resistance with the current detecting end is through equivalent environment, the same terms is made down, be input to amplifier one side behind backfeed loop and current mirroring circuit mirror image, and the left side is the detected current IS S of current detecting end, directly be input to the amplifier opposite side by current-mirror structure, if the both sides electric current equates that then amplifier is normally exported, the entire circuit operate as normal.If the both sides electric current does not wait, then amplifier plays amplification, and is influential to subsequent conditioning circuit.Adjust feedback by this approach, finally realize high-precision high-side current detection circuit.
Obviously, those skilled in the art can carry out various changes and modification to the present invention and not break away from the spirit and scope of the present invention.Like this, if of the present invention these are revised and modification belongs within the scope of claim of the present invention and equivalent technologies thereof, then the present invention also is intended to comprise these changes and modification interior.
Claims (8)
1. an electric current detecting method is characterized in that, comprises step:
Obtain the detection electric current;
Generate reference current;
According to described detection electric current and reference current, judge whether detect electric current reaches predetermined value.
2. detection method as claimed in claim 1 is characterized in that the current value of reference current equals described predetermined value; And
Under the situation of the current value that equals reference current that detects electric current, judge the detection electric current and reach predetermined value, do not reach predetermined value otherwise judge.
3. detection method as claimed in claim 1 is characterized in that, described judgement detects electric current and whether reaches predetermined value, specifically comprises step:
Generate benchmark and merge electric current, its current value equals described predetermined value and reference current value sum, and two branch currents of this benchmark merging electric current access, and wherein a branch current is for detecting electric current, and another branch current is a reference current;
Judge whether detect current value equals the poor of benchmark merging current value and reference current value,, do not reach otherwise judge as if equating, then judge that detecting current value reaches predetermined value.
4. detection method as claimed in claim 1 is characterized in that, described judgement detects electric current and whether reaches predetermined value, specifically comprises step:
Generate benchmark and split electric current, its current value equals the poor of described predetermined value and reference current value, and two branch currents of reference current access, and wherein a branch current is for detecting electric current, and another branch current is that benchmark splits electric current;
Judge whether detect electric current equals benchmark fractionation current value and reference current value sum,, do not reach otherwise judge as if equating, then judge that detecting current value reaches predetermined value.
5. a current detection circuit is characterized in that, comprising:
Detect the electric current acquisition module, be used to obtain the detection electric current;
The reference current generation module is used to generate reference current;
Detection module is used for detection electric current that obtains based on detection electric current acquisition module and the reference current that generates based on the reference current generation module, detects the detection electric current and whether reaches predetermined value.
6. current detection circuit as claimed in claim 5 is characterized in that the current value of described reference current equals described predetermined value; And
Described detection module specifically comprises:
Detect electric current and receive submodule, be used for receiving the detection electric current;
Reference current receives submodule, is used to receive reference current;
Comparison sub-module is used for the benchmark electric current and detects electric current, if both current values are equal, determines that then detecting electric current reaches predetermined value, does not reach predetermined value otherwise determine to detect electric current.
7. current detection circuit as claimed in claim 5 is characterized in that, described detection module specifically comprises:
Benchmark merges electric current and generates submodule, be used to generate benchmark and merge electric current, its current value equals described predetermined value and reference current value sum, and this benchmark merges two branch currents of electric current access, wherein a branch current is for detecting electric current, and another branch current is a reference current;
First judges submodule, is used for judging whether detect current value equals the poor of benchmark merging current value and reference current value, as if equating, then judge that detecting current value reaches predetermined value, does not reach otherwise judge.
8. current detection circuit as claimed in claim 5 is characterized in that, described detection module specifically comprises:
Benchmark splits electric current and generates submodule, be used to generate benchmark and split electric current, its current value equals the poor of described predetermined value and reference current value, and reference current inserts two branch currents, wherein a branch current is for detecting electric current, and another branch current is that benchmark splits electric current;
Second judges submodule, is used for judging whether detect electric current equals benchmark fractionation current value and reference current value sum, as if equating, then judge that detecting current value reaches predetermined value, does not reach otherwise judge.
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| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN 201010186716 CN101871962A (en) | 2010-05-27 | 2010-05-27 | Current detecting method and circuit |
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| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN 201010186716 CN101871962A (en) | 2010-05-27 | 2010-05-27 | Current detecting method and circuit |
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Cited By (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN102243261A (en) * | 2011-03-30 | 2011-11-16 | 上海北京大学微电子研究院 | Current detection circuit |
| CN102539889A (en) * | 2012-01-17 | 2012-07-04 | 惠州三华工业有限公司 | Multi-path high-voltage small current detecting circuit |
Citations (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN1795392A (en) * | 2003-05-29 | 2006-06-28 | 皇家飞利浦电子股份有限公司 | Undercurrent sense arrangement and method |
| EP1816483A1 (en) * | 2006-02-03 | 2007-08-08 | Siemens Aktiengesellschaft | Short-circuit and overcurrent detection circuit |
-
2010
- 2010-05-27 CN CN 201010186716 patent/CN101871962A/en active Pending
Patent Citations (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN1795392A (en) * | 2003-05-29 | 2006-06-28 | 皇家飞利浦电子股份有限公司 | Undercurrent sense arrangement and method |
| EP1816483A1 (en) * | 2006-02-03 | 2007-08-08 | Siemens Aktiengesellschaft | Short-circuit and overcurrent detection circuit |
Non-Patent Citations (1)
| Title |
|---|
| 《科技信息》 20071231 周成豪 等 《新型电流比较器的设计》 第14-16页 1-8 , 第36期 2 * |
Cited By (3)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN102243261A (en) * | 2011-03-30 | 2011-11-16 | 上海北京大学微电子研究院 | Current detection circuit |
| CN102539889A (en) * | 2012-01-17 | 2012-07-04 | 惠州三华工业有限公司 | Multi-path high-voltage small current detecting circuit |
| CN102539889B (en) * | 2012-01-17 | 2014-05-28 | 惠州三华工业有限公司 | Multi-path high-voltage small current detecting circuit |
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Owner name: NINGBO DELIN MACHINERY CO., LTD. Free format text: FORMER OWNER: DINGRUI IND + TRADE CO., LTD., NINGBO Effective date: 20101102 |
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Inventor after: Zou Zhu Inventor after: Zhang Yaoguo Inventor after: Shen Li Inventor after: Cheng Yuhua Inventor before: Zou Zha Inventor before: Zhang Yaoguo Inventor before: Shen Li Inventor before: Cheng Yuhua |
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Free format text: CORRECT: ADDRESS; FROM: 315010 18/F, TIANYUAN BUILDING, NO.9, JIEFANG SOUTH ROAD, HAISHU DISTRICT, NINGBO CITY, ZHEJIANG PROVINCE TO: 315020 NO.406, JIANGHU ROAD, INVESTMENT VENTURE PARK, JIANGBEI DISTRICT, NINGBO CITY |
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Open date: 20101027 |