CN205721468U - A kind of constant-current source circuit - Google Patents
A kind of constant-current source circuit Download PDFInfo
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- CN205721468U CN205721468U CN201620425837.5U CN201620425837U CN205721468U CN 205721468 U CN205721468 U CN 205721468U CN 201620425837 U CN201620425837 U CN 201620425837U CN 205721468 U CN205721468 U CN 205721468U
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Abstract
This utility model provides a kind of constant-current source circuit, and described constant-current source circuit includes: for exporting the voltage source of constant current；For providing the reference power supply unit of default reference voltage；Changed load voltage by described voltage source thus control the load unit of load current；The sampling unit of sampled voltage is obtained for the electric current of load unit being carried out sampling；For obtaining the voltage error between sampled voltage and reference voltage and voltage error being fed back to voltage source, so that voltage source exports electric current to ensure the comparison feedback unit of constant output current according to the feedback voltage regulation received；For controlling the switch element of the break-make between voltage source and load unit；For the maintenance when voltage source and load unit separated to the voltage holding unit of described voltage source feedback voltage.This utility model can allow constant-current source realize current switching within the time of hundreds of nanosecond to several microseconds.
Description
Technical field
This utility model relates to electronic circuit technology field, controls technical field particularly to constant-current source, is specially a kind of constant-current source
Circuit.
Background technology
Constant-current source is a widely used assembly in circuit, and constant-current source is the current source of output constant current hold, and preferable
Constant-current source should have the following characteristics that and not change because of load (output voltage) change；Do not change because of variation of ambient temperature；
Internal resistance is infinitely great (so that its electric current can all flow out to outside).The essence of constant-current source is to utilize device to carry out electric current instead
Feedback, dynamically regulates the power supply state of equipment, so that electric current tends to constant.As long as electric current can be obtained, it is possible to effectively shape
Become feedback, thus set up constant-current source.But in big electric current is applied, often there is higher the asking of dedicated current source chip price
Topic.A kind of method feasible in engineering is to use cheap voltage source chip, utilizes sampling resistor pressure drop to feed back, it is achieved permanent
The function in stream source.But its essence is still that the voltage loaded by change, make to be changed by the electric current of load.When needing
During electric current to be closed, voltage need to be dropped to the degree not having electric current in load by voltage source.When needs provide electric current again, then need
Voltage is added to original voltage.It is to say, the bigger problem that this circuit exists is that voltage chips is in order to reach mesh
Mark electric current, generally requires certain Voltage Establishment time.During this period of time typically between hundreds of microseconds are to several milliseconds.Some are needed
For the application of electric current to be switched fast, this time is unacceptable.
Utility model content
The shortcoming of prior art in view of the above, the purpose of this utility model is to provide a kind of constant-current source circuit, is used for solving
Prior art use voltage source chip open and close slow-footed problem when doing constant-current source.
For achieving the above object and other relevant purposes, this utility model provides a kind of constant-current source circuit, described constant-current source circuit bag
Include: for exporting the voltage source of constant current；For providing the reference power supply unit of default reference voltage；By described voltage source
Change load voltage thus control the load unit of load current；It is connected with described load unit, for described load unit
Electric current carries out sampling and obtains the sampling unit of sampled voltage；It is connected with described reference power supply unit and described sampling unit respectively, uses
In described sampled voltage and described reference voltage being compared the voltage obtained between described sampled voltage and described reference voltage by mistake
Described voltage error is also fed back to described voltage source by difference, so that described voltage source is according to the feedback voltage regulation output electricity received
Flow to ensure the comparison feedback unit of described constant output current；It is arranged between described voltage source and described load unit, is used for
Control the switch element of break-make between described voltage source and described load unit；It is arranged at described voltage source and compares feedback with described
Between unit, for the maintenance when described voltage source and described load unit separated to described voltage source feedback voltage
Voltage holding unit.
In an embodiment of the present utility model, described switch element includes metal-oxide-semiconductor or audion.
In an embodiment of the present utility model, described voltage holding unit includes: multiplexer, described multiplexer
First input end is connected with the described feedback unit that compares, and the outfan of described multiplexer is connected with described voltage source；Modulus turns
Parallel operation, be connected to the first input end of described multiplexer with on the described circuit compared between feedback unit at described electricity
Described feedback voltage is gathered during conducting between potential source and described load unit；Digital to analog converter, with the second of described multiplexer
Input connects and is connected with described analog-digital converter for when described voltage source and described load unit separated, and continuing will
Described feedback voltage feeds back to the outfan of described multiplexer.
In an embodiment of the present utility model, described voltage holding unit includes: analog switch, the first of described analog switch
Input is connected with the described feedback unit that compares, the second output head grounding of described analog switch；Storage capacitor, one end is with described
The outfan of analog switch is connected, other end ground connection, for charging during conducting between described voltage source and described load unit,
Continue to provide described voltage to described voltage source during described voltage source and described load unit separated；Operational amplifier, positive
Input is connected with the outfan of described storage capacitor and described analog switch, and outfan is connected with described voltage source, for by institute
The voltage that stating storage capacitor provides is amplified mating with described feedback voltage.
In an embodiment of the present utility model, the inverting input of described operational amplifier is used for preventing through one after being connected with outfan
Ground connection after only the resistance of concussion connects.
In an embodiment of the present utility model, described constant-current source circuit also includes: be connected to described sampling unit and described comparison
After the sampled voltage of described sampling unit is amplified, the described amplification list comparing feedback unit is fed back between feedback unit
Unit.
For achieving the above object, this utility model also provides for a kind of constant-current source control method, and described constant-current source control method includes:
Utilize the break-make between voltage source and the load under extraneous control signal of on-off control output constant current；At described voltage source
During with described regulating load separated, the output voltage keeping described voltage source is constant.
In an embodiment of the present utility model, metal-oxide-semiconductor or audion is utilized to control the voltage source of output constant current with outside
The break-make between load under boundary's control signal.
In an embodiment of the present utility model, when described voltage source and described regulating load separated, keep described voltage
The output voltage in source is constant to be specifically included: voltage source described in Gather and input during conducting between described voltage source and described regulating load
Feedback voltage, when described voltage source and described regulating load separated, continue described feedback voltage is fed back to described electricity
Potential source.
In an embodiment of the present utility model, when described voltage source and described regulating load separated, keep described voltage
The output voltage in source is constant to be specifically included: storage electric energy during conducting between described voltage source and described regulating load, at described electricity
During potential source and described regulating load separated, continue to provide voltage to keep the output voltage of described voltage source to described voltage source
Constant.
As it has been described above, a kind of constant-current source circuit of the present utility model, have the advantages that
1, this utility model utilizes the break-make between switch control voltage source and regulating load, and in described voltage source and regulating load
Separated time maintenance to described voltage source feedback voltage, make voltage source chip output voltage protect when electric current is switched on and off cut-out
Hold constant, when switch is again turned on, eliminate the Voltage Establishment time, constant-current source can be allowed in the time of extremely several microseconds of hundreds of nanosecond
Inside realize current switching, efficiently solve and prior art uses voltage source chip open and close slow-footed asking when doing constant-current source
Topic.
2, this utility model simple in construction, controls flexibly, economical and practical, has wide applicability.
Accompanying drawing explanation
Fig. 1 is shown as the theory diagram of a kind of constant-current source circuit of the present utility model.
Fig. 2 is shown as the structural representation of a kind of constant-current source circuit of the present utility model.
Fig. 3 is shown as a kind of preferred structure schematic diagram of voltage holding unit in a kind of constant-current source circuit of the present utility model.
Fig. 4 is shown as the another kind of preferred structure schematic diagram of voltage holding unit in a kind of constant-current source circuit of the present utility model.
Element numbers explanation
1 constant-current source circuit
11 voltage sources
12 reference power supply unit
13 load units
14 sampling units
15 compare feedback unit
16 switch elements
17 voltage holding units
Detailed description of the invention
Below by way of specific instantiation, embodiment of the present utility model being described, those skilled in the art can be by this specification institute
The content disclosed understands other advantages of the present utility model and effect easily.This utility model can also be by the most different tools
Body embodiment is carried out or applies, and the every details in this specification can also be based on different viewpoints and application, at the not back of the body
Various modification or change is carried out under spirit of the present utility model.
In a kind of constant-current source circuit in the present embodiment, by voltage source as constant-current source, wherein voltage source chip output voltage by by
On sampling resistor, voltage and setting voltage obtain through error comparator.By this method, voltage source can be treated as constant-current source
Use.But its essence is still that the voltage loaded by change, make to be changed by the electric current of load.Prior art
In employing voltage source as constant-current source time, when needs close electric current time, voltage source voltage need to be dropped to load on there is no electric current
Degree.When needs provide electric current again, then need to add to voltage original voltage.
The purpose of the present embodiment is to provide a kind of constant-current source circuit, is used for solving to use voltage source chip to do constant current in prior art
Slow-footed problem is opened and closed during source.The principle of a kind of constant-current source circuit of the present embodiment described in detail below and embodiment party
Formula, makes those skilled in the art need not creative work and is i.e. appreciated that a kind of constant-current source circuit of the present embodiment.
The present embodiment provides a kind of constant-current source circuit, specifically, as it is shown in figure 1, described constant-current source circuit 1 includes: voltage source
11, reference power supply unit 12, load unit 13, sampling unit 14, compares feedback unit 15, switch element 16 and voltage
Holding unit 17.
A kind of physical circuit figure of described constant-current source circuit 1 is as shown in Figure 2.
In the present embodiment, described voltage source 11 is used for exporting constant current, voltage source chip U1 of described voltage source 11 defeated
Go out the feedback voltage V that voltage is obtained by feedbackfbControl.
In the present embodiment, described reference power supply unit 12 is used for providing default reference voltage, and described load unit 13 is by institute
State voltage source change load voltage thus control load current.By the voltage changed in load unit 13 in load, make by negative
Electric current in load is changed, thus matches with the change of external loading.As in figure 2 it is shown, described load unit 13 can
Realized by regulation resistance R.
In the present embodiment, described sampling unit 14 is connected with described load unit 13, for the electricity to described load unit 13
Stream carries out sampling and obtains sampled voltage.Specifically, as in figure 2 it is shown, in the present embodiment, described sampling unit 14 is by sampling electricity
Resistance Rs is constituted, and the electric current that sampling resistor Rs exchanges on economize on electricity resistance R is sampled, and obtains sampled voltage.
In the present embodiment, described constant-current source circuit 1 also includes: is connected to described sampling unit 14 and described compares feedback unit
After the sampled voltage of described sampling unit 14 is amplified, the described amplification list comparing feedback unit 15 is fed back between 15
Unit.The sampled voltage amplified device A1 that sampling is obtained by described sampling unit 14 feeds back to compare in feedback unit 15 after amplifying.
In the present embodiment, described compare feedback unit 15 respectively with described reference power supply unit 12 and described sampling unit 14 phase
Even, for described sampled voltage and described reference voltage being compared between the described sampled voltage of acquisition and described reference voltage
Described voltage error is also fed back to described voltage source 11 by voltage error, so that described voltage source 11 is according to the feedback electricity received
Pressure regulation output electric current is to ensure described constant output current.Specifically, the described feedback unit 15 that compares is an error comparator
A2, the voltage Vset that feedback voltage Vfb is set by voltage Vs on sampling resistor Rs and described reference power supply unit 12 is through error
Comparator A2 obtains.
In the present embodiment, described switch element 16 is arranged between described voltage source 11 and described load unit 13, is used for controlling
Make the break-make between described voltage source 11 and described load unit 13.Specifically, in the present embodiment, described switch element 16
Including metal-oxide-semiconductor or audion.It is to say, in the present embodiment, utilize metal-oxide-semiconductor or audion to control to export constant electricity
Break-make between voltage source 11 and the load under extraneous control signal of stream.Owing to metal-oxide-semiconductor or triode switch are very rapid,
So constant-current source can be allowed to realize current switching within the time of hundreds of nanosecond to several microseconds.
In the present embodiment, described voltage holding unit 17 be arranged at described voltage source 11 with described compare feedback unit 15 it
Between, feed back electricity for the maintenance when described voltage source 11 and described load unit 13 separated to described voltage source 11
Pressure.Wherein, described voltage holding unit 17 can be by following two circuit realiration at described voltage source 11 and described load unit
13 separated time maintenance to described voltage source 11 feedback voltage.
As it is shown on figure 3, in the present embodiment, described voltage holding unit 17 includes: multiplexer, described multiplexer
First input end S1 be connected with the described feedback unit 15 (error amplifier shown in Fig. 3) that compares, described multiplexing
The outfan D of device is connected with described voltage source 11 (exporting feedback voltage Vfb to described voltage source 11)；Analog-digital converter (figure
ADC shown in 3), the first input end S1 being connected to described multiplexer compares between feedback unit 15 with described
For gathering described feedback voltage Vfb during conducting between described voltage source 11 and described load unit 13 on circuit；Digital-to-analogue turns
Parallel operation (DAC shown in Fig. 3), be connected with the second input S2 of described multiplexer and with described analog-digital converter
DAC is connected for when described voltage source 11 and described load unit 13 separated, continuing anti-for described feedback voltage Vfb
It is fed to the outfan D of described multiplexer.
In above-mentioned voltage holding unit 17, feedback voltage Vfb uses analog-digital converter ADC to sample.Work as constant-current source
When needing to close current source, feedback voltage Vfb is produced by analog-digital converter DAC, is used for keeping voltage source 11 output voltage not
Become.When constant-current source normally provides output electric current in running order, feedback voltage Vfb is set by described reference power supply unit 12
Voltage Vset and sampling resistor Rs sampling obtain actual voltage value between difference control.
As shown in Figure 4, in the present embodiment, described voltage holding unit 17 can also be realized by circuits below: described voltage
Holding unit 17 includes: at least include analog switch and storage capacitor.
Specifically, described analog switch (MUX shown in Fig. 4), the first input end Y0 of described analog switch is with described
Relatively feedback unit 15 (error amplifier) connects, the second outfan Y1 filtered electric capacity C2 ground connection of described analog switch；Storage
Energy electric capacity C1, one end is connected with the outfan of described analog switch, other end ground connection, is used at described voltage source 11 with described
Charging during conducting between load unit 13, continues to described voltage during described voltage source 11 and described load unit 13 separated
Source 11 provides described voltage；Operational amplifier, normal phase input end is connected with the outfan of described storage capacitor and described analog switch,
Outfan is connected with described voltage source 11, for the voltage that described storage capacitor provides is amplified with described feedback voltage
Join.Wherein, through one for preventing the resistance connection of concussion to be followed by after the inverting input of described operational amplifier is connected with outfan
Ground.
It is to say, described voltage holding unit 17 can be by analog switch, storage capacitor and operational amplifier are constituted.Work as constant current
When source normally provides output electric current in running order, the voltage Vset that feedback voltage Vfb is set by described reference power supply unit 12
With the difference between the actual voltage value of sampling resistor Rs sampling acquisition controls, described storage capacitor is charged, when constant-current source needs
During current source to be closed, described storage capacitor continues to provide described voltage to described voltage source 11, by the electric capacity of described storage capacitor
Electric charge maintains voltage output.
In sum, this utility model utilizes the break-make between switch control voltage source and regulating load, and described voltage source with
During regulating load separated, maintenance is to described voltage source feedback voltage, makes voltage source chip defeated when electric current is switched on and off cut-out
Go out voltage and keep constant, when switch is again turned on, eliminate the Voltage Establishment time, constant-current source can be allowed to several micro-in hundreds of nanosecond
Realize current switching in the time of second, efficiently solve and prior art uses voltage source chip open and close speed when doing constant-current source
Spend slow problem.This utility model simple in construction, controls flexibly, economical and practical, has wide applicability.So, this reality
Effectively overcome various shortcoming of the prior art with novel and have high industrial utilization.
Above-described embodiment only illustrative principle of the present utility model and effect thereof, not for limiting this utility model.Any
Above-described embodiment all can be modified under spirit and the scope of the present utility model or change by those skilled in the art.
Therefore, such as art has usually intellectual without departing from the spirit disclosed in this utility model with under technological thought
All equivalences completed are modified or change, and must be contained by claim of the present utility model.
Claims (6)
1. a constant-current source circuit, it is characterised in that: described constant-current source circuit includes:
For exporting the voltage source of constant current；
For providing the reference power supply unit of default reference voltage；
Changed load voltage by described voltage source thus control the load unit of load current；
It is connected with described load unit, obtains the sampling list of sampled voltage for the electric current of described load unit is carried out sampling
Unit；
It is connected with described reference power supply unit and described sampling unit respectively, for by described sampled voltage and described reference voltage
Compare the voltage error obtained between described sampled voltage and described reference voltage and described voltage error is fed back to institute
State voltage source, so that described voltage source exports electric current to ensure described constant output current according to the feedback voltage regulation received
Comparison feedback unit；
It is arranged between described voltage source and described load unit, for controlling between described voltage source and described load unit
The switch element of break-make；
It is arranged at described voltage source and compares between feedback unit with described, between described voltage source and described load unit
During disconnection, maintenance is to the voltage holding unit of described voltage source feedback voltage.
Constant-current source circuit the most according to claim 1, it is characterised in that: described switch element includes metal-oxide-semiconductor or audion.
Constant-current source circuit the most according to claim 1, it is characterised in that: described voltage holding unit includes:
Multiplexer, the first input end of described multiplexer is connected with the described feedback unit that compares, described multiplexing
The outfan of device is connected with described voltage source；
Analog-digital converter, be connected to the first input end of described multiplexer with on the described circuit compared between feedback unit
For gathering described feedback voltage during conducting between described voltage source and described load unit；
Digital to analog converter, is connected with the second input of described multiplexer and is connected in institute with described analog-digital converter
When stating voltage source and described load unit separated, continue to feed back to described feedback voltage the output of described multiplexer
End.
Constant-current source circuit the most according to claim 1, it is characterised in that: described voltage holding unit includes:
Analog switch, the first input end of described analog switch is connected with the described feedback unit that compares, the of described analog switch
Two output head groundings；
Storage capacitor, one end is connected with the outfan of described analog switch, other end ground connection, in described voltage source and institute
Charging when stating between load unit conducting, during described voltage source and described load unit separated, continuation carries to described voltage source
For described voltage；
Operational amplifier, normal phase input end is connected with the outfan of described storage capacitor and described analog switch, outfan and institute
State voltage source to be connected, for being amplified mating with described feedback voltage by the voltage that described storage capacitor provides.
Constant-current source circuit the most according to claim 4, it is characterised in that: the inverting input of described operational amplifier and outfan
After Xiang Lianing through one for prevent concussion resistance connect after ground connection.
Constant-current source circuit the most according to claim 1, it is characterised in that: described constant-current source circuit also includes: adopt described in being connected to
Sample unit and described compare feed back to after the sampled voltage of described sampling unit is amplified between feedback unit described
The relatively amplifying unit of feedback unit.
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| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN201620425837.5U CN205721468U (en) | 2016-05-11 | 2016-05-11 | A kind of constant-current source circuit |
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| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN201620425837.5U CN205721468U (en) | 2016-05-11 | 2016-05-11 | A kind of constant-current source circuit |
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| CN205721468U true CN205721468U (en) | 2016-11-23 |
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Cited By (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN105843315A (en) * | 2016-05-11 | 2016-08-10 | 国神光电科技（上海）有限公司 | Constant current source control method and constant current source circuit |
| CN113671324A (en) * | 2021-08-13 | 2021-11-19 | 中广核核电运营有限公司 | Automatic testing device for testing performance of medium-low voltage distribution board and testing method thereof |
-
2016
- 2016-05-11 CN CN201620425837.5U patent/CN205721468U/en active Active
Cited By (3)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN105843315A (en) * | 2016-05-11 | 2016-08-10 | 国神光电科技（上海）有限公司 | Constant current source control method and constant current source circuit |
| CN113671324A (en) * | 2021-08-13 | 2021-11-19 | 中广核核电运营有限公司 | Automatic testing device for testing performance of medium-low voltage distribution board and testing method thereof |
| CN113671324B (en) * | 2021-08-13 | 2023-11-24 | 中广核核电运营有限公司 | Automatic testing device and method for testing performance of medium-low voltage distribution board |
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