CN104460793A - High-accuracy programmable current source - Google Patents
High-accuracy programmable current source Download PDFInfo
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- CN104460793A CN104460793A CN201310417621.5A CN201310417621A CN104460793A CN 104460793 A CN104460793 A CN 104460793A CN 201310417621 A CN201310417621 A CN 201310417621A CN 104460793 A CN104460793 A CN 104460793A
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Abstract
The invention belongs to the field of electronic products, and particularly relates to a high-accuracy programmable current source. The high-accuracy programmable current source comprises a DAC (digital-to-analog converter) chip, an operational amplifier, an N-channel MOS (metal oxide semiconductor) transistor, a feedback sampling resistor R1 and a filter capacitor C1. The DAC chip is used for receiving digital signals sent by a processor, outputting current signals and determining current source accuracy and range; the operational amplifier is used for feedback modulation of the current signals to determine current source output accuracy; the N-channel MOS transistor is used for receiving currents outputted by the operational amplifier and sending the currents to its grid electrode so as to provide the currents for a load RL of its drain electrode. The high-accuracy programmable current source has the advantages the high-accuracy programmable current source has high compatibility and can be connected with a DSP (digital signal processor) and an ARM conveniently, peripheral circuits are few, the area of a PCB (printed circuit board) can be reduced effectively, debugging is facilitated, current output capability is high, output range of the current source can be changed according to load requirements on the premise of guaranteeing high accuracy, and stability is high.
Description
Technical field
The invention belongs to electronics field, be specifically related to a kind of high-precision programmable current source.
Background technology
Current source is most important in numerous applications, as power management, solenoid control, Electric Machine Control, impedance measurement, sensor excitation and medical treatment detection device etc.Industry and instrument system and programmable logic controller (PLC) and dcs, usually need the output valve of control current source.Therefore, in existing application, programmable current source is often directly adopted to realize.
But in above-mentioned traditional programmable current source application, output signal there will be the situation that precision is not high enough or amplitude range is wide not.In such circumstances, if widen the signal output area of programmable current source more further, so the precision of output current then can decline further.
Summary of the invention
The object of the invention is to overcome the problem that existing current source precision is not high enough and scope is wide not.
For this reason, the invention provides a kind of high-precision programmable current source, comprise a DAC chip, for the digital signal that receiving processor sends, output current signal, and the precision and the scope that determine current source; One operational amplifier, for the feedback modulation of current signal, guarantees the precision that current source exports; One N-channel MOS pipe, the electric current exported by reception operational amplifier to the grid of metal-oxide-semiconductor, thus provides electric current to the load RL of drain electrode; One feedback sample resistance R1, is serially connected in the pin 10(RFB of DAC chip) and N-channel MOS pipe source electrode between; One filter capacitor C1, is serially connected in the pin 10(RFB of DAC chip) and N-channel MOS pipe source electrode between.
Above-mentioned high-precision programmable current source, the pin 1(IOUT1 of described DAC chip) connect high precision CMOS operational amplifier OP1177 negative pole; OP1177 negative pole connects the pin 10(RFB of DAC chip by electric capacity C1), the pin 2(IOUT2 of DAC chip) be connected with amplifier OP1177 positive pole, and ground connection; The output of amplifier OP1177 is connected with the grid of metal-oxide-semiconductor; The pin 9(VREF of DAC chip) connect reference voltage; Pin 3(GND) ground connection.
Above-mentioned high-precision programmable current source, the resistance of described feedback sample resistance R1 is 100.
Above-mentioned high-precision programmable current source, the resistance of described feedback sample resistance R1 is 100; The capacity of filter capacitor C1 is 3pF.
Beneficial effect of the present invention: this high-precision programmable current source provided by the invention, comprises a DAC chip, for the digital signal that receiving processor sends, output current signal, and the precision and the scope that determine current source; One operational amplifier, for the feedback modulation of current signal, guarantees the precision that current source exports; One N-channel MOS pipe, the electric current exported by reception operational amplifier to the grid of metal-oxide-semiconductor, thus provides electric current to the load RL of drain electrode; One feedback sample resistance R1, is serially connected in the pin 10(RFB of DAC chip) and N-channel MOS pipe source electrode between; One filter capacitor C1, is serially connected in the pin 10(RFB of DAC chip) and N-channel MOS pipe source electrode between; This high-precision programmable current source has good compatibility, can after be connected with DSP, ARM very easily, peripheral circuit is few, PCB surface can be effectively reduced amass, debugging is convenient, output current ability is strong, can ensure under the prerequisite that precision is high according to load requirement change the output area of current source, stability is high.
Below with reference to accompanying drawing, the present invention is described in further details.
Accompanying drawing explanation
Fig. 1 is high-precision programmable current source hardware principle schematic diagram.
Embodiment
Embodiment 1:
A kind of high-precision programmable current source as shown in Figure 1, comprise DAC chip (AD5446), operational amplifier (OP1177), N-channel MOS pipe (2N3797), feedback sample resistance R1, filter capacitor C1, the pin 4(SCLK of DAC chip), pin 5(SDIN), pin 6(SYNC#) connect input signal, pin 1(IOUT1) connect high precision CMOS operational amplifier OP1177 negative pole; OP1177 negative pole connects the pin 10(RFB of DAC chip by electric capacity C1), the pin 2(IOUT2 of DAC chip) be connected with amplifier OP1177 positive pole, and ground connection; The output of amplifier OP1177 is connected with the grid of metal-oxide-semiconductor; The pin 9(VREF of DAC chip) meet reference voltage, pin 8(VDD) connect 5V power supply; Pin 3(GND) ground connection; Power supply VCC is connected with the drain electrode of metal-oxide-semiconductor by load RL; Feedback sample resistance R1, is serially connected between N-channel MOS pipe source electrode and ground connection.
The use step of this high-precision programmable current source:
(1) required device is connected according to described in claim 1;
(2) scope of the output current needed for load, selected reference voltage V
rEF;
(3) computational load electric current:
（1）
Wherein D is the fractional representation being loaded into DAC numeral.But, R
dACmuch larger than R1, therefore load current can become by approximate representation:
（2）
Comprehensive above-described embodiment, this high-precision programmable current source has good compatibility, the standard SPI mouth that DAC carries can be connected with DSP, ARM very easily, hardware circuit simple and stable, peripheral circuit is few, PCB surface can be effectively reduced amass, output current ability is strong, can ensure under the high prerequisite of precision according to load requirement change the output area of current source, stability is high, select the high resolving power DAC chip of 14 or 16, under the condition that output area is certain, resolution can reach μ A level.
More than exemplifying is only illustrate of the present invention, does not form the restriction to protection scope of the present invention, everyly all belongs within protection scope of the present invention with the same or analogous design of the present invention.
Claims (4)
1. a high-precision programmable current source, is characterized in that, comprising:
One DAC chip, for the digital signal that receiving processor sends, output current signal, and the precision and the scope that determine current source;
One operational amplifier, for the feedback modulation of current signal, guarantees the precision that current source exports;
One N-channel MOS pipe, the electric current exported by reception operational amplifier to the grid of metal-oxide-semiconductor, thus provides electric current to the load RL of drain electrode;
One feedback sample resistance R1, is serially connected between N-channel MOS pipe source electrode and ground connection;
One filter capacitor C1, is serially connected in the pin 10(RFB of DAC chip) and metal-oxide-semiconductor source electrode between.
2. high-precision programmable current source as claimed in claim 1, is characterized in that: the pin 1(IOUT1 of described DAC chip) connect high precision CMOS operational amplifier OP1177 negative pole; OP1177 negative pole connects the pin 10(RFB of DAC chip by electric capacity C1), the pin 2(IOUT2 of DAC chip) be connected with amplifier OP1177 positive pole, and ground connection; The output of amplifier OP1177 is connected with the grid of metal-oxide-semiconductor; The pin 9(VREF of DAC chip) connect reference voltage; Pin 3(GND) ground connection.
3. high-precision programmable current source as claimed in claim 1, is characterized in that: the resistance of described feedback sample resistance R1 is 100.
4. high-precision programmable current source as claimed in claim 1, is characterized in that: the capacity of described filter capacitor C1 is 3pF.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN201310417621.5A CN104460793A (en) | 2013-09-14 | 2013-09-14 | High-accuracy programmable current source |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN201310417621.5A CN104460793A (en) | 2013-09-14 | 2013-09-14 | High-accuracy programmable current source |
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| CN104460793A true CN104460793A (en) | 2015-03-25 |
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| CN201310417621.5A Pending CN104460793A (en) | 2013-09-14 | 2013-09-14 | High-accuracy programmable current source |
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Cited By (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN109343433A (en) * | 2018-11-22 | 2019-02-15 | 湖南恩智测控技术有限公司 | A kind of high-accuracy high-resolution programmable power supply circuit |
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| CN201312260Y (en) * | 2008-09-28 | 2009-09-16 | 比亚迪股份有限公司 | Digital power circuit and digital power provided with the circuit |
| CN102736653A (en) * | 2012-06-28 | 2012-10-17 | 何泽骅 | Voltage-stabilized power supply of numerical controlled switch |
| CN203520217U (en) * | 2013-09-14 | 2014-04-02 | 西安奇维科技股份有限公司 | High-precision programmable current source |
| CN205450860U (en) * | 2016-03-16 | 2016-08-10 | 深圳市比特原子科技有限公司 | Constant -current source circuit with adjustable it is small -size |
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2013
- 2013-09-14 CN CN201310417621.5A patent/CN104460793A/en active Pending
Patent Citations (6)
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| US6600439B1 (en) * | 2000-11-08 | 2003-07-29 | Micron Technology, Inc. | Reference voltage circuit for differential analog-to-digital converter |
| US6859157B1 (en) * | 2003-01-31 | 2005-02-22 | Inovys Corporation | Programmable precision current controlling apparatus |
| CN201312260Y (en) * | 2008-09-28 | 2009-09-16 | 比亚迪股份有限公司 | Digital power circuit and digital power provided with the circuit |
| CN102736653A (en) * | 2012-06-28 | 2012-10-17 | 何泽骅 | Voltage-stabilized power supply of numerical controlled switch |
| CN203520217U (en) * | 2013-09-14 | 2014-04-02 | 西安奇维科技股份有限公司 | High-precision programmable current source |
| CN205450860U (en) * | 2016-03-16 | 2016-08-10 | 深圳市比特原子科技有限公司 | Constant -current source circuit with adjustable it is small -size |
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Cited By (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN109343433A (en) * | 2018-11-22 | 2019-02-15 | 湖南恩智测控技术有限公司 | A kind of high-accuracy high-resolution programmable power supply circuit |
| CN109343433B (en) * | 2018-11-22 | 2024-04-02 | 湖南恩智测控技术有限公司 | High-precision high-resolution programmable power supply circuit |
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Application publication date: 20150325 |