CN207968332U - A kind of constant-current device - Google Patents
A kind of constant-current device Download PDFInfo
- Publication number
- CN207968332U CN207968332U CN201820419331.2U CN201820419331U CN207968332U CN 207968332 U CN207968332 U CN 207968332U CN 201820419331 U CN201820419331 U CN 201820419331U CN 207968332 U CN207968332 U CN 207968332U
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- current
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- constant
- power tube
- capacitance
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Abstract
The utility model is related to a kind of constant-current devices,Logic control element controls the conducting of the first power tube,The armature winding of first transformer starts energy storage,The signal of the first power tube of shutdown is generated according to first comparator,The energy of first transformer storage is discharged by secondary windings,Due to the relationship of auxiliary winding and secondary windings same-phase,It can obtain the demagnetization duty ratio of auxiliary winding,Demagnetization duty cycle signals are transferred to electric current gating unit by demagnetization dutycycle detector unit,Control the break-make of electric current gating unit,Reference current unit is pull-down current source,It is that the first capacitance discharges always,When reaching dynamic equilibrium,The average current that electric current gating unit flows into is equal to the pull-down current of reference current unit,The output current of this constant-current device is only related with the reference current of reference current unit,When different voltages export,Realize constant current output,Any sampling resistor of Circuit Fault on Secondary Transformer is not needed,Save exterior space and cost,Improve whole efficiency.
Description
Technical field
The utility model is related to field of switch power, more particularly to a kind of constant-current device.
Background technology
It is more next high to the capacity requirement of battery with the rapid proliferation of big screen intelligent mobile phone, corresponding charging rate
It is required that be getting faster, present fast charge field than it is more typical be exactly QC3.0, QC4.0；The charge power of QC4.0 reaches close
30W, five volts of output gear output currents can reach 6A, and most popular QC3.0 instantly, QC4.0 charging circuit, mostly use change
Constant flow sample resistance is arranged in the mode of depressor secondary side constant current, and sampling resistor will at least get 10m Ω, on sampling resistor
0.36W is at least lost in face, and the efficiency of whole system is made to reduce by 1.5%.
Utility model content
Technical problem to be solved in the utility model is：One kind is provided and does not need Circuit Fault on Secondary Transformer setting sampling resistor
Constant-current device, save exterior space and cost, improve whole efficiency.
In order to solve the above-mentioned technical problem, the technical solution adopted in the utility model is：A kind of constant-current device, including first
Resistance, second resistance, the first capacitance, the second capacitance, demagnetization dutycycle detector unit, electric current gating unit, reference current unit,
Voltage turns current unit, logic control element, first comparator, the first power tube and the first transformer, first transformer
Including armature winding, secondary windings and auxiliary winding；
One end of the auxiliary winding is connected with one end of first resistor, the other end ground connection of the auxiliary winding；
The other end of the first resistor is connected with one end of second resistance and demagnetization dutycycle detector unit respectively, described
The other end of second resistance is grounded, and the demagnetization dutycycle detector unit is connected with electric current gating unit；
The electric current gating unit turns current unit with the negative input of first comparator and voltage respectively and is connected, described
The output end of first comparator is connected by logic control element with the first end of the first power tube, and the of first power tube
Two ends are connected with the electrode input end of first comparator, and the logic control element turns current unit by voltage and gated with electric current
Unit is connected, and the third end of first power tube is connected with armature winding, and the both ends of the secondary windings are electric with second respectively
Hold and is connected；
The reference current unit is connected with the negative input of first comparator, one end of first capacitance and benchmark
Current unit is connected, the other end ground connection of first capacitance.
The beneficial effects of the utility model are：Logic control element controls the conducting of the first power tube, the first transformer
Armature winding starts energy storage, and the signal of the first power tube of shutdown, the energy of the first transformer storage are generated according to first comparator
It is discharged by secondary windings, due to the relationship of auxiliary winding and secondary windings same-phase, the demagnetization that can obtain auxiliary winding accounts for
Demagnetization duty cycle signals are transferred to electric current gating unit by empty ratio, demagnetization dutycycle detector unit, control electric current gating unit
Break-make, reference current unit are pull-down current source, are discharged for the first capacitance always, and when reaching dynamic equilibrium, electric current gating is single
The average current that member flows into is equal to the pull-down current of reference current unit, the output current of this constant-current device only with reference current list
The reference current of member is related, when different voltages export, realizes constant current output, does not need Circuit Fault on Secondary Transformer setting sampling electricity
Exterior space and cost are saved in resistance, improve whole efficiency.
Description of the drawings
Fig. 1 is the structural schematic diagram according to a kind of embodiment of constant-current device of the utility model；
Label declaration：
R1, first resistor；R2, second resistance；R3,3rd resistor；C1, the first capacitance；C2, the second capacitance；1, demagnetization accounts for
Sky compares detection unit；2, electric current gating unit；3, reference current unit；4, voltage turns current unit；5, logic control element；6、
Current sample holding unit；7, sampling pulse generates unit；U1, first comparator；Q1, the first power tube；NP, armature winding；
NS, secondary windings；
NA, auxiliary winding.
Specific implementation mode
For technology contents, the objects and the effects of the utility model are described in detail, below in conjunction with embodiment and match
Attached drawing is closed to be explained.
The design of the utility model most critical is：Output current is only related with the reference current of reference current unit,
When different voltages export, constant current output is realized.
Please refer to Fig. 1, a kind of constant-current device, including first resistor, second resistance, the first capacitance, the second capacitance, demagnetization account for
Sky turns current unit than detection unit, electric current gating unit, reference current unit, voltage, logic control element, first compares
Device, the first power tube and the first transformer, first transformer include armature winding, secondary windings and auxiliary winding；
One end of the auxiliary winding is connected with one end of first resistor, the other end ground connection of the auxiliary winding；
The other end of the first resistor is connected with one end of second resistance and demagnetization dutycycle detector unit respectively, described
The other end of second resistance is grounded, and the demagnetization dutycycle detector unit is connected with electric current gating unit；
The electric current gating unit turns current unit with the negative input of first comparator and voltage respectively and is connected, described
The output end of first comparator is connected by logic control element with the first end of the first power tube, and the of first power tube
Two ends are connected with the electrode input end of first comparator, and the logic control element turns current unit by voltage and gated with electric current
Unit is connected, and the third end of first power tube is connected with armature winding, and the both ends of the secondary windings are electric with second respectively
Hold and is connected；
The reference current unit is connected with the negative input of first comparator, one end of first capacitance and benchmark
Current unit is connected, the other end ground connection of first capacitance.
As can be seen from the above description, the beneficial effects of the utility model are：Logic control element controls the first power tube and leads
Logical, the armature winding of the first transformer starts energy storage, and the signal of the first power tube of shutdown is generated according to first comparator, and first becomes
The energy of depressor storage is discharged by secondary windings, due to the relationship of auxiliary winding and secondary windings same-phase, can be obtained auxiliary
It helps the demagnetization duty ratio of winding, demagnetization dutycycle detector unit that demagnetization duty cycle signals are transferred to electric current gating unit, controls
The break-make of electric current gating unit, reference current unit are pull-down current source, are the electric discharge of the first capacitance always, when reaching dynamic equilibrium
When, the average current that electric current gating unit flows into is equal to the pull-down current of reference current unit, the output current of this constant-current device
It is only related with the reference current of reference current unit, when different voltages export, realizes constant current output, do not need transformer secondary
Sampling resistor is arranged in side, saves exterior space and cost, improves whole efficiency.
Further, further include that the current sample holding unit being connected with each other and sampling pulse generate unit, the electric current
Sample holding unit turns current unit with voltage respectively and the electrode input end of first comparator is connected, and the sampling pulse generates
Unit is connected with logic control element.
Seen from the above description, current sample holding unit is used to sample the voltage of 3rd resistor, by the electricity of 3rd resistor
Pressure samples inside current sample holding unit, and sampled voltage is transferred to voltage and turns current unit by current sample holding unit.
Further, the sampling time that the sampling pulse generates unit is the half of the turn-on cycle of the first power tube.
Seen from the above description, sampling pulse generates opening time of the unit by the first power tube of detection, generates corresponding
Sampling pulse, the time that sampling pulse starts sampling are the half of the first power tube turn-on cycle.
Further, further include 3rd resistor, one end of the 3rd resistor is connected with the second end of the first power tube, institute
State the other end ground connection of 3rd resistor.
Seen from the above description, 3rd resistor is used to detect the electric current of the first power tube, and the pressure drop of generation is input to first
Comparator.
Further, further include the first diode, the anode of first diode is connected with one end of secondary windings, institute
The cathode for stating the first diode is connected by the second capacitance with the other end of secondary windings.
Seen from the above description, the first diode is used for when secondary windings is connected, and provides continuous current circuit, transformer is deposited
Energy storage capacity is transferred to the second capacitance.
Further, second capacitance and load parallel connection.
Seen from the above description, the second capacitance is output capacitance, connects output loading, realizes the condition of different output voltages
Under, obtain constant current output.
Fig. 1 is please referred to, the embodiments of the present invention one are：
A kind of constant-current device, including first resistor R1, second resistance R2, the first capacitance C1, the second capacitance C2, demagnetization duty
Turn current unit 4 than detection unit 1, electric current gating unit 2, reference current unit 3, voltage, logic control element 5, first compares
Compared with device U1, the first power tube Q1 and the first transformer, first transformer includes armature winding NP, secondary windings NS and auxiliary
Winding NA；
One end of the auxiliary winding is connected with one end of first resistor, the other end ground connection of the auxiliary winding；
The other end of the first resistor is connected with one end of second resistance and demagnetization dutycycle detector unit respectively, described
The other end of second resistance is grounded, and the demagnetization dutycycle detector unit is connected with electric current gating unit；
The electric current gating unit turns current unit with the negative input of first comparator and voltage respectively and is connected, described
The output end of first comparator is connected by logic control element with the first end of the first power tube, and the of first power tube
Two ends are connected with the electrode input end of first comparator, and the logic control element turns current unit by voltage and gated with electric current
Unit is connected, and the third end of first power tube is connected with armature winding, and the both ends of the secondary windings are electric with second respectively
Hold and is connected；
The reference current unit is connected with the negative input of first comparator, one end of first capacitance and benchmark
Current unit is connected, the other end ground connection of first capacitance；
A kind of constant-current device further includes that the current sample holding unit 6 being connected with each other and sampling pulse generate list
Member 7, the current sample holding unit turns current unit with voltage respectively and the electrode input end of first comparator is connected, described
Sampling pulse generates unit and is connected with logic control element, and the sampling time that the sampling pulse generates unit is the first power tube
Turn-on cycle half；
A kind of constant-current device further includes 3rd resistor R3, one end of the 3rd resistor and the first power tube
Second end is connected, the other end ground connection of the 3rd resistor；
A kind of constant-current device further includes the first diode, anode and the secondary windings of first diode
One end is connected, and the cathode of first diode is connected by the second capacitance with the other end of secondary windings.
The turn ratio of second capacitance and load parallel connection, the armature winding and secondary windings is n, and n is constant,
First power tube is triode or metal-oxide-semiconductor.
Three windings, including armature winding NP, secondary windings NS and auxiliary winding are arranged in the first transformer of the utility model
NA, logic control element, which generates, opens the first power tube signal, and after the first power tube is opened, the inductance of armature winding starts to store up
Can, the signal of the first power tube of shutdown is generated according to first comparator, after the first power tube is closed, the energy of the first transformer storage
Amount is discharged by secondary windings NS, and demagnetization starts, and due to the relationship of auxiliary winding and secondary windings same-phase, passes through auxiliary winding
It can accurately detect the erasing time of secondary windings, and then obtain demagnetization duty ratio, pass through first resistor and second resistance
The demagnetization signal of auxiliary winding and vice-side winding can be detected, demagnetization dutycycle detector unit is connected to first resistor and the second electricity
Resistance detects the demagnetization duty cycle information of first resistor and second resistance, by demagnetization signal transmission to electric current gating unit, control electricity
The break-make for flowing gating unit, when secondary windings demagnetization starts, voltage is turned the electricity of current unit conversion by the conducting of electric current gating unit
Stream gating is entered, and the first capacitor charging, the first capacitance voltage is given to increase, and when secondary windings demagnetization terminates, demagnetization duty ratio detects
Unit sends out the signal for closing electric current gating unit, stops to the first capacitor charging；Reference current unit works always, for drop-down
Current source discharges for the first capacitance always, and when reaching dynamic equilibrium, the average current that electric current gating unit flows into is equal to benchmark
The pull-down current of current unit, expression formula are as follows:
If demagnetization duty ratio is D, the electric current that voltage turns electric current conversion is I, and reference current unit output current is I1, then full
Foot：
I*D=I1 (1)；
First power tube is opened, and the inductance of armature winding starts energy storage, and 3rd resistor presses voltage linear to increase, logic control
The opening time of first power tube is transferred to sampling pulse and generates unit by unit, generates sampling pulse, and sampling pulse generates single
For member after the conducting of the first power tube, the half for the upper first power tube turn-on time that is delayed generates an impulse sampling, this arteries and veins
Punching sampling firing current sample holding unit samples the voltage of 3rd resistor inside current sample holding unit, and electric current is adopted
Sampled voltage is transferred to voltage and turns current unit by sample holding unit, is transformed into electric current I, and specific constant current expression formula is as follows：
If the turn ratio of armature winding and secondary windings is n, output current Iout, demagnetization duty ratio is D, 3rd resistor
Voltage when sampling is V, and the electric current when inductance of armature winding is begun to turn on is Ip1, and the voltage of 3rd resistor is V1 at this time, is closed
Electric current is Ip2 when disconnected, and the voltage of 3rd resistor is V2 at this time；The electric current when inductance of secondary windings is begun to turn on is Is1, is terminated
When electric current be Is2, the resistance value of 3rd resistor is R, and it is k that voltage, which turns current coefficient, and it is Vs that sampling, which keeps voltage, then output current
Expression formula is：
Iout=D* (Is1-Is2)/2 (2)；
Is1=n*Ip2=n*V2/R (3)；
Is2=n*Ip1=n*V1/R (4)；
Vs=(V2-V1)/2 (5)；
It obtains：Iout=D* (Is1-Is2)/2=n*D (V2-V1)/2R=n*D*Vs/R； (6)
After the completion of the wherein turn ratio n of the armature winding and secondary windings and resistance value R of 3rd resistor is by default, this
Two are fixed values.
I=Vs*k (7)；
It can be obtained by (1) formula：
Vs*k*D=I1 (8), it can be deduced that：
Iout=n*I1/ (k*R), wherein n and R, k definite value.
Output current Iout and I1 is linear, i.e. output current Iout is solely dependent upon I1, and I1 is internal reference electricity
Stream is fixed value, therefore output current Iout is also fixed value, and when the utility model realizes different voltages output, constant current is defeated
Go out.
In conclusion a kind of constant-current device provided by the utility model, logic control element controls the conducting of the first power tube,
The armature winding of first transformer starts energy storage, and the signal of the first power tube of shutdown, the first transformation are generated according to first comparator
The energy of device storage is discharged by secondary windings, due to the relationship of auxiliary winding and secondary windings same-phase, can be assisted
Demagnetization duty cycle signals are transferred to electric current gating unit, control electricity by the demagnetization duty ratio of winding, demagnetization dutycycle detector unit
The break-make of gating unit is flowed, reference current unit is pull-down current source, is the electric discharge of the first capacitance always, when reaching dynamic equilibrium
When, the average current that electric current gating unit flows into is equal to the pull-down current of reference current unit, the output current of this constant-current device
It is only related with the reference current of reference current unit, when different voltages export, realizes constant current output, do not need transformer secondary
Sampling resistor is arranged in side, saves exterior space and cost, improves whole efficiency.
The above description is only the embodiments of the present invention, and it does not limit the scope of the patent of the present invention, every
Equivalents made based on the specification and figures of the utility model are applied directly or indirectly in relevant technology neck
Domain is equally included in the patent within the scope of the utility model.
Claims (8)
1. a kind of constant-current device, which is characterized in that accounted for including first resistor, second resistance, the first capacitance, the second capacitance, demagnetization
Sky turns current unit than detection unit, electric current gating unit, reference current unit, voltage, logic control element, first compares
Device, the first power tube and the first transformer, first transformer include armature winding, secondary windings and auxiliary winding；
One end of the auxiliary winding is connected with one end of first resistor, the other end ground connection of the auxiliary winding；
The other end of the first resistor is connected with one end of second resistance and demagnetization dutycycle detector unit respectively, and described second
The other end of resistance is grounded, and the demagnetization dutycycle detector unit is connected with electric current gating unit；
The electric current gating unit turns current unit with the negative input of first comparator and voltage respectively and is connected, and described first
The output end of comparator is connected by logic control element with the first end of the first power tube, the second end of first power tube
It is connected with the electrode input end of first comparator, the logic control element turns current unit and electric current gating unit by voltage
Be connected, the third end of first power tube is connected with armature winding, the both ends of the secondary windings respectively with the second capacitance phase
Even；
The reference current unit is connected with the negative input of first comparator, one end of first capacitance and reference current
Unit is connected, the other end ground connection of first capacitance.
2. a kind of constant-current device according to claim 1, which is characterized in that further include that the current sample being connected with each other is kept
Unit and sampling pulse generate unit, and the current sample holding unit turns current unit and first comparator with voltage respectively
Electrode input end is connected, and the sampling pulse generates unit and is connected with logic control element.
3. a kind of constant-current device according to claim 2, which is characterized in that when the sampling pulse generates the sampling of unit
Between for the first power tube turn-on cycle half.
4. a kind of constant-current device according to claim 1, which is characterized in that further include 3rd resistor, the 3rd resistor
One end be connected with the second end of the first power tube, the other end of 3rd resistor ground connection.
5. a kind of constant-current device according to claim 1, which is characterized in that further include the first diode, the described 1st
The anode of pole pipe is connected with one end of secondary windings, and the cathode of first diode is another by the second capacitance and secondary windings
One end is connected.
6. a kind of constant-current device according to claim 1, which is characterized in that second capacitance and load parallel connection.
7. a kind of constant-current device according to claim 1, which is characterized in that the number of turns of the armature winding and secondary windings
Than being constant for n, n.
8. a kind of constant-current device according to claim 1, which is characterized in that first power tube be triode or
Metal-oxide-semiconductor.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN201820419331.2U CN207968332U (en) | 2018-03-27 | 2018-03-27 | A kind of constant-current device |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN201820419331.2U CN207968332U (en) | 2018-03-27 | 2018-03-27 | A kind of constant-current device |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| CN207968332U true CN207968332U (en) | 2018-10-12 |
Family
ID=63726284
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CN201820419331.2U Withdrawn - After Issue CN207968332U (en) | 2018-03-27 | 2018-03-27 | A kind of constant-current device |
Country Status (1)
| Country | Link |
|---|---|
| CN (1) | CN207968332U (en) |
Cited By (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN108365757A (en) * | 2018-03-27 | 2018-08-03 | 深圳市群芯科创电子有限公司 | A kind of constant-current device |
-
2018
- 2018-03-27 CN CN201820419331.2U patent/CN207968332U/en not_active Withdrawn - After Issue
Cited By (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN108365757A (en) * | 2018-03-27 | 2018-08-03 | 深圳市群芯科创电子有限公司 | A kind of constant-current device |
| CN108365757B (en) * | 2018-03-27 | 2023-10-17 | 深圳市群芯科创电子有限公司 | Constant-current device |
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Granted publication date: 20181012 Effective date of abandoning: 20231017 |
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| AV01 | Patent right actively abandoned |
Granted publication date: 20181012 Effective date of abandoning: 20231017 |
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| AV01 | Patent right actively abandoned |