CN104345207A - DC-DC load current acquisition processing circuit - Google Patents
DC-DC load current acquisition processing circuit Download PDFInfo
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- CN104345207A CN104345207A CN201310312154.XA CN201310312154A CN104345207A CN 104345207 A CN104345207 A CN 104345207A CN 201310312154 A CN201310312154 A CN 201310312154A CN 104345207 A CN104345207 A CN 104345207A
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Abstract
The invention discloses a DC-DC load current acquisition processing circuit. The DC-DC load current acquisition processing circuit comprises a single-source power supply type Hall current sensor, a high common mode inhibition ratio operational amplifier and a current follower, wherein the output voltage of the single-source power supply type Hall current sensor is connected with the positive input end of the high common mode inhibition ratio operational amplifier and is grounded through a first capacitor, the conversion reference voltage of the single-source power supply type Hall current sensor is connected with the negative input end of the high common mode inhibition ratio operational amplifier, the positive source end is connected with first voltage, and the negative source end of the single-source power supply type Hall current sensor is grounded; the positive input end of the high common mode inhibition ratio operational amplifier is grounded through a first resistor, the negative input end of the high common mode inhibition ratio operational amplifier is grounded through a second resistor, the positive source end of the high common mode inhibition ratio operational amplifier is connected with second voltage, the negative source end is grounded, and the output end of the high common mode inhibition ratio operational amplifier is connected with the positive input end of the current follower and is grounded through a second capacitor; and the positive source end of the current follower is connected with the second voltage, the negative source end of the current follower is grounded, the negative input end of the current follower is connected with the output end of the current follower, and the output end of the current follower is grounded through a third capacitor. The circuit provided by the invention is simple in structure and has a good isolation effect with a DC-DC loop.
Description
Technical field
The present invention relates to electronic circuit field, particularly relate to a kind of DC-DC load current acquisition process circuit.
Background technology
For the collection of DC-DC load current, usually there are three kinds of acquisition methods at present, are respectively circuit in series resistance sampling method, negative and positive dual power Hall element sampling method and current clamp sampling method.
Circuit in series resistance sampling method is connected in series sampling resistor in DC-DC load circuit, exports after being amplified by low noise amplifier; The advantage of resistance sampling method is that cost is lower, and shortcoming is that subsequent process circuit is complicated, and sampling resistor can affect the impedance operator of DC-DC load circuit itself, and cannot realize the isolation with DC-DC loop.
Negative and positive dual power Hall element sampling method is that use ± 12V or ± 15V dual power supply are powered to Hall-type current sensor, makes the output voltage reference point of current sensor remain 0V, conveniently carries out follow-up signal process.But negative and positive dual power supply circuit more complicated, cost is very high, uses inconvenience.
The advantage of current clamp sampling method uses circuit simple, and treatment circuit is placed in current clamp, and shortcoming is that current clamp cost is higher.
Summary of the invention
The technical problem to be solved in the present invention is to provide the DC-DC load current acquisition process circuit that the simple and DC-DC loop of a kind of circuit structure has good isolation effect.
For solving the problems of the technologies described above, DC-DC load current acquisition process circuit of the present invention, comprising:
One single power supply formula Hall current sensor U1, its output voltage Sout connect high cmrr operational amplifier U2 positive input terminal and by the first electric capacity C1 ground connection GND, its switching reference voltages Vref connects the negative input end of high cmrr operational amplifier U2, its positive supply termination first voltage vcc 1, its negative power end ground connection GND;
High cmrr operational amplifier U2, its positive input terminal is by the first resistance R1 ground connection GND, its negative input end is by the second resistance R2 ground connection GND, its positive supply termination second voltage vcc 2, its negative power end ground connection GND, it exports the positive input terminal of termination current follower U3 and passes through the second electric capacity C2 ground GND;
Current follower U3, its positive supply termination second voltage vcc 2, its negative power end ground connection GND, its negative input end connects its output end vo ut, and its output end vo ut is by the 3rd electric capacity C3 ground connection GND.
Wherein, the second voltage vcc 2 is greater than the maximum output voltage of high cmrr operational amplifier U2.
Wherein, the enlargement factor of high cmrr operational amplifier U2 is 2 to 20 times.
The feature of the DC-DC load current that need gather is as follows:
Variation range: 0 ~ 50A, saltus step step-length: 5A, saltus step interval: 1ms
In order to realize the collection of above current signal, choosing range is that the single power supply formula Hall current sensor of 50A is as acquisition elements, during 0A, the output voltage of this sensor is Vref, during full scale 50A, output voltage is Vref+0.625V(reference voltage Vref ≈ 2.5V), this voltage signal has following two features:
Reference voltage is not 0V, but Vref;
Gather electric current when full scale changes, output voltage variation range very little (0.625V).
Due to above two features, follow-up shaping and amplifying return circuit need being increased, carrying out subsequent acquisition and process to facilitate the voltage signal to exporting.
The present invention is by current acquisition, shaping, amplification, filtering and follow 5 parts such as conversion and form, and FB(flow block) as shown in Figure 1.By reasonable circuit design, by the voltage signal that Hall current sensor exports, carry out shaping amplification, filtering and after following conversion, export in analog voltage mode.Owing to adopting Hall-type current sensor, do not affect the normal work of load circuit, there is good isolation effect.Analog voltage mode exports, and has good collection property power.This device highly versatile, unipolarity power mode works, and can be transplanted to the occasion that other need to gather electric current easily.The present invention is not affecting under the prerequisite that DC-DC normally uses, adopt the Hall-type current sensor of low cost, add the rectification of simple resolution element composition, filtering and follow circuit, avoid the high cost problem of resistance sampling method on the impact of DC-DC load circuit and current clamp sampling method well, can be good at gathering DC-DC load current waveform, have good isolation effect, circuit structure is simple, working stability, reliability is high.
Accompanying drawing explanation
Below in conjunction with accompanying drawing and embodiment, the present invention is further detailed explanation:
Fig. 1 is the schematic diagram of DC-DC load current acquisition process circuit of the present invention.
Fig. 2 is the structural representation of DC-DC load current acquisition process circuit of the present invention.
Embodiment
As shown in Figure 2, DC-DC load current acquisition process circuit of the present invention, comprising:
One single power supply formula Hall current sensor U1, its output voltage Sout connect high cmrr operational amplifier U2 positive input terminal and by the first electric capacity C1 ground connection GND, its switching reference voltages Vref connects the negative input end of high cmrr operational amplifier U2, its positive supply termination first voltage vcc 1, its negative power end ground connection GND;
High cmrr operational amplifier U2, its positive input terminal is by the first resistance R1 ground connection GND, its negative input end is by the second resistance R2 ground connection GND, its positive supply termination second voltage vcc 2, its negative power end ground connection GND, it exports the positive input terminal of termination current follower U3 and passes through the second electric capacity C2 ground GND; The enlargement factor of high cmrr operational amplifier U2 is 2 to 20 times, general employing 10 times of high cmrr operational amplifiers.
Current follower U3, its positive supply termination second voltage vcc 2, its negative power end ground connection GND, its negative input end connects its output end vo ut, its output end vo ut is by the 3rd electric capacity C3 ground connection GND, and the second voltage vcc 2 is greater than the maximum output voltage of high cmrr operational amplifier U2.
Below through the specific embodiment and the embodiment to invention has been detailed description, but these are not construed as limiting the invention.Without departing from the principles of the present invention, those skilled in the art also can make many distortion and improvement, and these also should be considered as protection scope of the present invention.
Claims (3)
1. a DC-DC load current acquisition process circuit, is characterized in that, comprising:
One single power supply formula Hall current sensor (U1), its output voltage (Sout) connects the positive input terminal of high cmrr operational amplifier (U2) and passes through the first electric capacity (C1) ground connection (GND), its switching reference voltages (Vref) connects the negative input end of high cmrr operational amplifier (U2), its positive supply termination first voltage (Vcc1), its negative power end ground connection (GND);
High cmrr operational amplifier (U2), its positive input terminal is by the first resistance (R1) ground connection (GND), its negative input end is by the second resistance (R2) ground connection (GND), its positive supply termination second voltage (Vcc2), its negative power end ground connection (GND), its positive input terminal exporting termination current follower (U3) is with also passing through the second electric capacity (C2) (GND);
Current follower (U3), its positive supply termination second voltage (Vcc2), its negative power end ground connection (GND), its negative input end connects its output terminal (Vout), and its output terminal (Vout) is by the 3rd electric capacity (C3) ground connection (GND).
2. DC-DC load current acquisition process circuit as claimed in claim 1, is characterized in that: the second voltage (Vcc2) needs to be greater than the maximum output voltage of high cmrr operational amplifier (U2).
3. DC-DC load current acquisition process circuit as claimed in claim 1, is characterized in that: the enlargement factor 2 to 20 times of high cmrr operational amplifier (U2).
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN201310312154.XA CN104345207A (en) | 2013-07-23 | 2013-07-23 | DC-DC load current acquisition processing circuit |
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| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN201310312154.XA CN104345207A (en) | 2013-07-23 | 2013-07-23 | DC-DC load current acquisition processing circuit |
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| CN104345207A true CN104345207A (en) | 2015-02-11 |
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| CN201310312154.XA Pending CN104345207A (en) | 2013-07-23 | 2013-07-23 | DC-DC load current acquisition processing circuit |
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Citations (7)
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|---|---|---|---|---|
| US4639665A (en) * | 1983-08-22 | 1987-01-27 | Borg-Warner Corporation | Sensing system for measuring a parameter |
| US20070257663A1 (en) * | 2006-05-08 | 2007-11-08 | Mende Michael J | Current sensing circuit for use in a current measurement probe |
| CN101655516A (en) * | 2008-08-20 | 2010-02-24 | 力博特公司 | Main-circuit input current detection device |
| CN101696985A (en) * | 2009-10-23 | 2010-04-21 | 刘旭明 | Method, device and system for detecting direct current |
| CN102096050A (en) * | 2010-12-10 | 2011-06-15 | 奇瑞汽车股份有限公司 | Detection device of direct current-direct current power supply circuit |
| CN102710109A (en) * | 2012-05-24 | 2012-10-03 | 浙江大学 | Current limiting circuit for DC/DC (Direct Current/Direct Current) converter |
| CN103163354A (en) * | 2011-12-08 | 2013-06-19 | 沈阳康特机电设备有限公司 | Electric current detection circuit of servo control system |
-
2013
- 2013-07-23 CN CN201310312154.XA patent/CN104345207A/en active Pending
Patent Citations (7)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US4639665A (en) * | 1983-08-22 | 1987-01-27 | Borg-Warner Corporation | Sensing system for measuring a parameter |
| US20070257663A1 (en) * | 2006-05-08 | 2007-11-08 | Mende Michael J | Current sensing circuit for use in a current measurement probe |
| CN101655516A (en) * | 2008-08-20 | 2010-02-24 | 力博特公司 | Main-circuit input current detection device |
| CN101696985A (en) * | 2009-10-23 | 2010-04-21 | 刘旭明 | Method, device and system for detecting direct current |
| CN102096050A (en) * | 2010-12-10 | 2011-06-15 | 奇瑞汽车股份有限公司 | Detection device of direct current-direct current power supply circuit |
| CN103163354A (en) * | 2011-12-08 | 2013-06-19 | 沈阳康特机电设备有限公司 | Electric current detection circuit of servo control system |
| CN102710109A (en) * | 2012-05-24 | 2012-10-03 | 浙江大学 | Current limiting circuit for DC/DC (Direct Current/Direct Current) converter |
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Application publication date: 20150211 |
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