CN203520217U - High-precision programmable current source - Google Patents
High-precision programmable current source Download PDFInfo
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- CN203520217U CN203520217U CN201320569261.6U CN201320569261U CN203520217U CN 203520217 U CN203520217 U CN 203520217U CN 201320569261 U CN201320569261 U CN 201320569261U CN 203520217 U CN203520217 U CN 203520217U
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Abstract
The utility model belongs to the field of electronic products, and particularly relates to a high-precision programmable current source. The high-precision programmable current source comprises a DAC chip, an operational amplifier, an N-channel MOS transistor, a feedback sampling resistor R1 and a filter capacitor C1. The DAC chip is used for receiving a digital signal sent by a processor, outputting a current signal and determining the precision and range of the current source; the operational amplifier is used for achieving feedback modulation of the current signal and guaranteeing the precision of output of the current source; current is provided for a load RL of the drain of the MOS transistor by receiving current output by the operational amplifier and transmitting the current to the grid of the MOS transistor. The high-precision programmable current source has very good compatibility, can be very conveniently connected with a DSP and an ARM, the number of peripheral circuits is small, the area of a PCB can be effectively reduced, debugging is convenient to carry out, current output ability is strong, it can be guaranteed that the output range of the current source is changed on the premise that precision is high, and stability is high.
Description
Technical field
The utility model belongs to electronic product field, is specifically related to a kind of high-precision programmable current source.
Background technology
Current source is most important in many application, 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 to control the output valve of current source.Therefore, in existing application, often directly adopt programmable current source to realize.
Yet 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.Under this environment, if further widen the signal output area of programmable current source, the precision of output current can further decline so again.
Utility model content
The purpose of this utility model is to overcome the not high enough and wide not problem of scope of existing current source precision.
For this reason, the utility model provides a kind of high-precision programmable current source, comprises a DAC chip, the digital signal of sending for receiving processor, output current signal, and precision and the scope of decision current source; One operational amplifier, for the feedback modulation of current signal, guarantees the precision of current source output; One N-channel MOS pipe, by receiving the electric current of operational amplifier output to the grid of metal-oxide-semiconductor, thereby provides electric current to the load RL of drain electrode; One feedback sample resistance R 1, 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) connection high precision CMOS operational amplifier OP1177 negative pole; OP1177 negative pole connects the pin 10(RFB of DAC chip by capacitor C 1), the pin 2(IOUT2 of DAC chip) be connected with amplifier OP1177 is anodal, 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 R 1 is 100.
Above-mentioned high-precision programmable current source, the resistance of described feedback sample resistance R 1 is 100; The capacity of filter capacitor C1 is 3pF.
The beneficial effects of the utility model: this high-precision programmable current source that the utility model provides, comprises a DAC chip, the digital signal of sending for receiving processor, output current signal, and precision and the scope of decision current source; One operational amplifier, for the feedback modulation of current signal, guarantees the precision of current source output; One N-channel MOS pipe, by receiving the electric current of operational amplifier output to the grid of metal-oxide-semiconductor, thereby provides electric current to the load RL of drain electrode; One feedback sample resistance R 1, 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, can effectively reduce PCB area, debugging is convenient, output current ability is strong, can guarantee 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 utility model 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 R 1, filter capacitor C1, the pin 4(SCLK of DAC chip), pin 5(SDIN), pin 6(SYNC#) connect input signal, pin 1(IOUT1) connection high precision CMOS operational amplifier OP1177 negative pole; OP1177 negative pole connects the pin 10(RFB of DAC chip by capacitor C 1), the pin 2(IOUT2 of DAC chip) be connected with amplifier OP1177 is anodal, 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 R 1, is serially connected between N-channel MOS pipe source electrode and ground connection.
The use step of this high-precision programmable current source:
(1) by required device according to connecting described in claim 1;
(2) according to the scope of the required output current of load, selected reference voltage V
rEF;
(3) computational load electric current:
Wherein D is the fractional representation that is written into DAC numeral.But, R
dACmuch larger than R1, so load current can become by approximate representation:
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, can effectively reduce PCB area, output current ability is strong, can guarantee under the prerequisite that precision is high according to load requirement change the output area of current source, stability is high, the high resolving power DAC chip of selecting 14 or 16, under the certain condition of output area, resolution is to μ A level.
More than exemplifying is only to illustrate of the present utility model, does not form the restriction to protection domain of the present utility model, within the every and same or analogous design of the utility model all belongs to protection scope of the present invention.
Claims (4)
1. a high-precision programmable current source, is characterized in that, comprising:
One DAC chip, the digital signal of sending for receiving processor, output current signal, and precision and the scope of decision current source;
One operational amplifier, for the feedback modulation of current signal, guarantees the precision of current source output;
One N-channel MOS pipe, by receiving the electric current of operational amplifier output to the grid of metal-oxide-semiconductor, thereby provides electric current to the load RL of drain electrode;
One feedback sample resistance R 1, is serially connected between N-channel MOS pipe source electrode and ground connection;
One filter capacitor C1, is serially connected between the pin 10 and metal-oxide-semiconductor source electrode of DAC chip.
2. high-precision programmable current source as claimed in claim 1, is characterized in that: the pin 1 of described DAC chip connects high precision CMOS operational amplifier OP1177 negative pole; OP1177 negative pole connects the pin 10 of DAC chip by capacitor C 1, the pin 2 of DAC chip is connected with amplifier OP1177 is anodal, and ground connection; The output of amplifier OP1177 is connected with the grid of metal-oxide-semiconductor; The pin 9 of DAC chip connects reference voltage; Pin 3 ground connection.
3. high-precision programmable current source as claimed in claim 1, is characterized in that: the resistance of described feedback sample resistance R 1 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 |
|---|---|---|---|
| CN201320569261.6U CN203520217U (en) | 2013-09-14 | 2013-09-14 | High-precision programmable current source |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN201320569261.6U CN203520217U (en) | 2013-09-14 | 2013-09-14 | High-precision programmable current source |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| CN203520217U true CN203520217U (en) | 2014-04-02 |
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Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CN201320569261.6U Expired - Lifetime CN203520217U (en) | 2013-09-14 | 2013-09-14 | High-precision programmable current source |
Country Status (1)
| Country | Link |
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| CN (1) | CN203520217U (en) |
Cited By (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN104460793A (en) * | 2013-09-14 | 2015-03-25 | 西安奇维科技股份有限公司 | High-accuracy programmable current source |
| CN104615186A (en) * | 2015-01-29 | 2015-05-13 | 深圳市辰卓科技有限公司 | High-precision adjustable power supply circuit |
-
2013
- 2013-09-14 CN CN201320569261.6U patent/CN203520217U/en not_active Expired - Lifetime
Cited By (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN104460793A (en) * | 2013-09-14 | 2015-03-25 | 西安奇维科技股份有限公司 | High-accuracy programmable current source |
| CN104615186A (en) * | 2015-01-29 | 2015-05-13 | 深圳市辰卓科技有限公司 | High-precision adjustable power supply circuit |
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Legal Events
| Date | Code | Title | Description |
|---|---|---|---|
| C14 | Grant of patent or utility model | ||
| GR01 | Patent grant | ||
| C56 | Change in the name or address of the patentee | ||
| CP01 | Change in the name or title of a patent holder |
Address after: 710000 Xi'an high tech Zone, Jin Industrial Road, No., No. C Venture Park, No. 8, Patentee after: XI'AN KEYWAY TECHNOLOGY Co.,Ltd. Address before: 710000 Xi'an high tech Zone, Jin Industrial Road, No., No. C Venture Park, No. 8, Patentee before: Xi'an Keyway Technology Co.,Ltd. |
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| CX01 | Expiry of patent term | ||
| CX01 | Expiry of patent term |
Granted publication date: 20140402 |