CN201936214U - Large power negative pressure numerical control constant current module - Google Patents
Large power negative pressure numerical control constant current module Download PDFInfo
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- CN201936214U CN201936214U CN 201120033732 CN201120033732U CN201936214U CN 201936214 U CN201936214 U CN 201936214U CN 201120033732 CN201120033732 CN 201120033732 CN 201120033732 U CN201120033732 U CN 201120033732U CN 201936214 U CN201936214 U CN 201936214U
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- resistance
- field effect
- operational amplifier
- numerical control
- negative pressure
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Abstract
The utility model discloses a large power negative pressure numerical control constant current module, which comprises a direct or alternating converting chip, a photoisolator, an operational amplifier and a feedback unit VMOS (vertical metal oxide semiconductor) field effect pipe, input signal is sequentially converted by the direct or alternating converting chip and the photoisolator, and then is input into a normal phase end of the operational amplifier, a grid voltage and a source voltage of the VMOS field effect pipe is feedback to a negative end of the operational amplifier by the feedback unit, after comparison operation, the operational amplifier outputs control signal to the grid of the VMOS field effect pipe so as to control the drainelectrode of the VMOS field effect pipe to output constant current. Under the condition that an input digital signal has the resolution of 10 bit, the module outputs a digital signal at the current of 0-1024 level, and inputs the current within a control range which changes in the range of 0-3 A by 1024 levels, with initial voltage larger than or equal to minus 0.5 V, current stability equal to 9.9*10-5, current temperature coefficient equal to 4.8*10-5, and maximum power consumption equal to 30 W.
Description
Technical field
The utility model belongs to power asic technology field, relates in particular to a kind of high-power negative pressure numerical control constant flow module.
Background technology
The numerical control constant flow module under the irreplaceable condition of traditional constant current device, propose research, it be a kind of be the constant flow module of feature with the Digital Signals output current.It not only the output current adjustable extent wide, allow that the operating voltage variation range is big, circuit interface and TTL compatible, and volume is little, easy to adjust, has good electrical property.Can be widely used in the technical field that traditional constant current device can't set foot in, in digital circuit technique is used, have special advantages.
Sheng Fasheng etc. disclose a kind of DCM02 type constant flow module (Sheng Fasheng, the model Arcam, the design analysis [J] of Lv Pin hardwood .DCM02 type numerical control constant current device. Hangzhou University's journal (natural science edition), 1997,24 (2): 125-132), this device bias voltage and TTL compatible have high-level efficiency, characteristics such as easy to use.
Sheng Fasheng etc. disclose a kind of numerical control constant current device (Sheng Fasheng, model Arcam, Bi Jing. a kind of high stability constant current device [J] that adopts Digital Signals. Chinese journal of scientific instrument, 1999,20 (3): 225-228), adopt modular construction, low in energy consumption, volume is little, and has good electrical property.
The application of above-mentioned device is worked under the positive voltage situation, can not work under the negative voltage situation, and not solve effective isolation of digital circuit part and artificial circuit part.
Summary of the invention
The utility model provides a kind of reliability height, volume is little, low in energy consumption and the high-power negative pressure numerical control constant flow module of easy adjusting.
A kind of high-power negative pressure numerical control constant flow module, comprise: D/A conversion chip, photoisolator, operational amplifier, feedback unit VMOS field effect transistor, the digital signal of input is the positive terminal of input operational amplifier after D/A conversion chip and photoisolator conversion successively, the negative phase end that feedback unit feeds back to operational amplifier with the grid voltage and the source voltage of VMOS field effect transistor, output control signals to the grid of VMOS field effect transistor after the operational amplifier comparison operation, the drain electrode output steady current of control VMOS field effect transistor.
Described D/A conversion chip adopts the serial digital signal input, and external the tenth resistance carries out the linear correction of the first order.
Described photoisolator output terminal and operational amplifier positive terminal are provided with linear amending unit, described linear amending unit is made up of second resistance, the 8th resistance, the 9th resistance and first resistance, the 9th resistance is in parallel with first resistance, resistance after the parallel connection is connected with second resistance, resistance after the series connection is in parallel with the 8th resistance, and this amending unit carries out the linear correction in the second level to constant flow module.
Above-mentioned constant flow module also comprises the 7th resistance that connects VMOS field effect transistor source electrode, regulates the feedback voltage of the 5th resistance, the 6th resistance of concatenation operation amplifier out; The 6th resistance, the 7th resistance, first resistance, the 8th resistance and the 9th resistance are connected common junction.
Described feedback unit comprises the 4th resistance and the 5th resistance in parallel, the negative phase end of the 4th resistance and the common concatenation operation amplifier of the 5th resistance one end, the other end connects the grid and the drain electrode of VMOS field effect transistor respectively, and constant flow module is carried out the linear correction of the third level.
The utility model also provides the application of above-mentioned high-power negative pressure numerical control constant flow module in power integrated circuit.
The utility model constant flow module is by using photoisolator, guarantee effective isolation of digital circuit and mimic channel, used three grades of linear corrections simultaneously, first order correction is in the D/A change-over circuit, and the linearity of step pitch electric current and the high precision of D/A conversion are guaranteed in its linear correction; The linear correction in the second level is the linearity output after the assurance opto-electronic conversion, and it is that the linearity that guarantees the VMOS pipe is exported that the third level is revised.
The artificial circuit part of the utility model constant flow module is worked under negative voltage, and starting potential is low, and the electric current adjustable extent is wide, circuit interface and TTL compatible, reliability height, little, low in energy consumption, the easy adjusting of volume.This module can be applicable to computer control, robot, optical fiber communication, military equipment, aspects such as intelligent instrumentation and other robotization control.
Description of drawings
Fig. 1 is the modular structure figure of the utility model constant flow module;
Fig. 2 is the circuit theory diagrams of the utility model galvanostat;
Fig. 3 is the volt-ampere characteristics of figure of the utility model constant flow module;
Fig. 4 is the utility model constant flow module control signal sequential chart;
Fig. 5 is the utility model constant flow module 10bit input and output corresponding relation figure.
Embodiment
As shown in the figure, a kind of high-power negative pressure numerical control constant flow module comprises D/A conversion chip U1, photoisolator U2, operational amplifier A, feedback unit B and VMOS field effect transistor VT.The digital signal of input is changed the positive terminal of input operational amplifier A successively through D/A conversion chip U1, photoisolator U2, the negative phase end that feedback unit feeds back to operational amplifier A with grid voltage and the source voltage of VMOS field effect transistor VT, output control signals to the grid of VMOS field effect transistor VT after the operational amplifier A comparison operation, the constant electric current of drain electrode output of control VMOS field effect transistor VT.
The D/A conversion chip adopts the serial digital-to-analog conversion, connects resistance R 10 outward and makes that the D/A reference power supply is adjustable.D/A conversion chip U1 is under the time clock effect, the digital signal of input is read in by turn by shift register, import 10 clock period pulses at interval at two latch pulses, latch 10 position digital signals and finish the D/A conversion, simulating signal after the D/A conversion and reference power supply compare back input photoisolator U2.
Connect linear amending unit between the output terminal of photoisolator U2 and the normal phase input end of operational amplifier A, this linearity amending unit is made up of resistance R 2, resistance R 8, resistance R 9 and resistance R 1, wherein the resistance of resistance R 1 and resistance R 9 parallel connections is connected with resistance R 2, and the resistance of series connection is in parallel with R8.By adjusting the resistance of resistance R 9, make the output of photoisolator U2 keep linear change, resistance R 3 corresponding resistance R 1 are provided with the negative phase end of concatenation operation amplifier A.
Feedback unit adopts the amplification bleeder circuit that increases feedback, reduces power attenuation; It is made up of resistance R 4 and resistance R 5, and resistance R 4 two ends are negative phase end and the output terminal of concatenation operation amplifier A respectively, the negative phase end of resistance R 5 two ends difference concatenation operation amplifier A and the source electrode of VMOS field effect transistor VT.
VMOS field effect transistor VT is the N channel-type, has the impedance height, drive current is little, mutual conductance is big, conducting resistance is low and does not have advantages such as second breakdown, guarantees that the module output current is constant.
For making VMOS field effect transistor VT grid voltage stable, the output terminal connection resistance R 6 in operational amplifier A is the needs of feedback regulation, in the source electrode connection resistance R 7 of metal-oxide-semiconductor field effect transistor VT.Resistance R 7, resistance R 1, resistance R 6, resistance R 8 and resistance R 9 common ends are connected power supply Vss, and load Rf one end connects the drain electrode of VMOS field effect transistor VT, other end ground connection.Resistance R 7, resistance R 9 and resistance R 10 are adjustable resistance.
Fig. 3 is the drain electrode output volt-ampere characteristics of figure of VMOS field effect transistor VT, work as on-load voltage as seen from the figure greater than certain numerical value, output current is invariable all the time, does not change with load variations, and the resolution of output current depends on the input figure place of D/A conversion chip.
Fig. 5 is above-mentioned constant flow module 10bit input and output corresponding relation figure, shows present embodiment module output current I
0Variation with digital signal changes, and linear between the two.Contextual definition between its output current and the input of digital signal amount is:
I
0＝K.I
REF.D2 (1)
I
0--module output current, D--binary digit amount, K--correction factor, I
REF--reference current, K wherein, I
REFAlso be that scale-of-two is converted into metric correction factor, formula (1) can be written as:
I
0＝K.I
REF.(a
02
0+a
12
1+......+a
m-12
m-1) (2)
With digital signal input resolution 10bit, maximum output current is that 3A is an example, K.I
REF=2.93, then by formula (2) the corresponding relation of digital quantity and analog quantity is:
I
0＝2.93(a
02
0+a
12
1+a
22
2+a
32
3+a
42
4+a
52
5+......+a
92
9)(mA) (3)
2.93mA is exactly the high-power negative pressure numerical control of a present embodiment constant flow module minimum controllable electric current in the formula (3), and accomplish that in force digital quantity is corresponding one by one with analog quantity, and maintenance high precision, be that output current divides 1024 grades of variations in 0～1024 stages of digital signal input range of control in 0～3A scope, starting potential 〉=-0.5V, current stability, 9.9 * 10
-5, current temperature coefficient 4.8 * 10
-5, maximum power dissipation 30W (Zhejiang Province's electronic product check test 09/01/2001).
Claims (5)
1. high-power negative pressure numerical control constant flow module, it is characterized in that, comprise D/A conversion chip (U1), photoisolator (U2), operational amplifier (A), feedback unit (B) and VMOS field effect transistor (VT), the digital signal of input is the positive terminal of input operational amplifier (A) after D/A conversion chip (U1) and photoisolator (U2) conversion successively, the negative phase end that feedback unit (B) feeds back to operational amplifier (A) with the grid voltage and the source voltage of VMOS field effect transistor (VT), output control signals to the grid of VMOS field effect transistor (VT) after operational amplifier (A) comparison operation, thereby make the drain electrode output current of VMOS field effect transistor (VT) constant.
2. high-power negative pressure numerical control constant flow module according to claim 1 is characterized in that, described D/A conversion chip (U1) adopts the serial digital signal input.
3. high-power negative pressure numerical control constant flow module according to claim 1, it is characterized in that, described photoisolator (U2) output terminal and operational amplifier (A) positive terminal are provided with linear amending unit, described linear amending unit is made up of second resistance (R2), the 8th resistance (R8), the 9th resistance (R9) and first resistance (R1), the 9th resistance (R9) is in parallel with first resistance (R1), resistance after the parallel connection is connected with second resistance (R2), and the resistance after the series connection is in parallel with the 8th resistance (R8).
4. high-power negative pressure numerical control constant flow module according to claim 3 is characterized in that, comprises the 7th resistance (R7) that connects VMOS field effect transistor (VT) source electrode, the 6th resistance (R6) of concatenation operation amplifier (A) output terminal; The 6th resistance (R6), the 7th resistance (R7), first resistance (R1), the 8th resistance (R8) and the 9th resistance (R9) are connected common junction.
5. high-power negative pressure numerical control constant flow module according to claim 1, it is characterized in that, described feedback unit is made up of the 4th resistance (R4) and the 5th resistance (R5), the negative phase end of the 4th resistance (R4) and the common concatenation operation amplifier of the 5th resistance (R5) end (A), the other end connect the grid and the drain electrode of VMOS field effect transistor (VT) respectively.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN 201120033732 CN201936214U (en) | 2011-01-31 | 2011-01-31 | Large power negative pressure numerical control constant current module |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN 201120033732 CN201936214U (en) | 2011-01-31 | 2011-01-31 | Large power negative pressure numerical control constant current module |
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| Publication Number | Publication Date |
|---|---|
| CN201936214U true CN201936214U (en) | 2011-08-17 |
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ID=44447731
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| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CN 201120033732 Expired - Lifetime CN201936214U (en) | 2011-01-31 | 2011-01-31 | Large power negative pressure numerical control constant current module |
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Cited By (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN102122186A (en) * | 2011-01-31 | 2011-07-13 | 浙江财经学院 | High-power negative pressure numerical control constant current module |
-
2011
- 2011-01-31 CN CN 201120033732 patent/CN201936214U/en not_active Expired - Lifetime
Cited By (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN102122186A (en) * | 2011-01-31 | 2011-07-13 | 浙江财经学院 | High-power negative pressure numerical control constant current module |
| CN102122186B (en) * | 2011-01-31 | 2012-12-26 | 浙江财经学院 | High-power negative pressure numerical control constant current module |
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Legal Events
| Date | Code | Title | Description |
|---|---|---|---|
| C14 | Grant of patent or utility model | ||
| GR01 | Patent grant | ||
| AV01 | Patent right actively abandoned |
Granted publication date: 20110817 Effective date of abandoning: 20130306 |
|
| RGAV | Abandon patent right to avoid regrant |