CN204157132U - Load voltage testing circuit - Google Patents
Load voltage testing circuit Download PDFInfo
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- CN204157132U CN204157132U CN201420634921.9U CN201420634921U CN204157132U CN 204157132 U CN204157132 U CN 204157132U CN 201420634921 U CN201420634921 U CN 201420634921U CN 204157132 U CN204157132 U CN 204157132U
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- load
- voltage
- circuit
- divider resistance
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Abstract
A kind of load voltage testing circuit, described load voltage testing circuit comprises: load power source circuit, divider resistance, switching circuit and voltage detecting circuit, described load power source circuit comprises load, diode and inductance, and described load, diode and inductance series connection form loop circuit, one end of described load power source circuit is connected with operating voltage input, the described other end of load power source circuit and the first end of switching circuit, the first end of divider resistance is connected, second end of described divider resistance is together with the second end ground connection of described switching circuit, described switching circuit is utilized to control for load voltage, point pressure side of described divider resistance is connected with the signal input part of voltage detecting circuit, described voltage detecting circuit keeps by sampling point pressure side feedback voltage obtaining divider resistance, and obtain load voltage by computing.Structure is simple, and detection efficiency is high, and cost is low.
Description
Technical field
The utility model relates to electric circuit inspection technical field, particularly a kind of load voltage testing circuit.
Background technology
Along with the fast development of LED, the design of LED drive circuit emerges in an endless stream.But existing LED drive circuit is in design all more complicated of the function aspects such as output overloading, overvoltage protection.Common LED load testing circuit adopts the method for Transformer Winding, causes circuit integrity more complicated, and volume is large, and cost is high.
Utility model content
The problem that the utility model solves is to provide the load voltage detection method of a kind of load voltage testing circuit and correspondence, and can obtain load voltage fast, circuit volume is little, and cost is low.
For solving the problem, the utility model embodiment provides a kind of load voltage testing circuit, comprise: load power source circuit, divider resistance, switching circuit and voltage detecting circuit, described load power source circuit comprises load, diode and inductance, and described load, diode and inductance series connection form loop circuit, one end of described load power source circuit is connected with operating voltage input, the described other end of load power source circuit and the first end of switching circuit, the first end of divider resistance is connected, second end of described divider resistance is together with the second end ground connection of described switching circuit, described switching circuit is utilized to control for load voltage, point pressure side of described divider resistance is connected with the signal input part of voltage detecting circuit, described voltage detecting circuit keeps by sampling point pressure side feedback voltage obtaining divider resistance, and obtain load voltage by computing.
Optionally, described voltage detecting circuit comprises signal input part, sampling keeps module, the first reference voltage module, averaging module and subtracter, described sampling keeps module to be connected with the first reference voltage module, and described sampling keeps one end of module to be connected with signal input part, one end of described first reference voltage module is as the first input end of subtracter, one end of described averaging module is connected with signal input part, and the other end is as the second input of subtracter.
Optionally, described voltage detecting circuit comprises signal input part, sampling keeps module, averaging module and subtracter, described sampling keeps module to be connected with subtracter, and described sampling keeps one end of module to be connected with signal input part, the other end of described subtracter is connected with signal input part, the input of described averaging module is connected with the output of subtracter, the output that the output of averaging module is institute's detectable voltage signals.
Optionally, described switching circuit is switching tube, and the first end of described switching tube is connected with the other end of load power source circuit, and the second end ground connection of described switching tube, the control end of described switching tube is connected with load control circuit.
Optionally, described voltage detecting circuit is arranged in load control circuit, when load voltage overvoltage being detected, utilizes the control end on-off switching tube of switching tube.
Optionally, described load is LED.
Optionally, described load power source circuit comprises: diode, inductance and load, one end of described load, the negative pole of diode are connected with operating voltage input, the other end of described load is connected with one end of inductance, and the other end of described inductance is connected with the positive pole of diode and is connected with the first end of switching circuit, the first end of divider resistance.
Optionally, described load power source circuit comprises: Transformer Winding, diode and load, described load one end is connected with the negative pole of diode, the described load other end is connected with one end of Transformer Winding secondary, the described other end of Transformer Winding secondary is connected with the positive pole of diode, the one end on the former limit of described Transformer Winding is connected with operating voltage input, and the other end on the former limit of described Transformer Winding is connected with the first end of switching circuit, the first end of divider resistance.
Optionally, described load power source circuit comprises: diode, inductance and load, one end of described load, one end of inductance are connected with operating voltage input, the other end of described load is connected with negative pole one end of diode, and positive pole one end of described diode is connected with the other end of inductance and is connected with the first end of switching circuit, the first end of divider resistance.
Optionally, described load power source circuit also comprises second electric capacity in parallel with load.
Compared with prior art, the technical program has the following advantages:
The technical program adopts divider resistance to obtain the voltage of the first end of divider resistance, and utilize voltage detecting circuit the voltage of the first end of kept divider resistance to be deducted the mean value of the first end voltage of divider resistance, or the voltage of the first end of kept divider resistance is deducted the first end real-time voltage of divider resistance, again this difference voltage is averaged, obtain load voltage, structure is simple, and detection efficiency is high, and cost is low.
Accompanying drawing explanation
Fig. 1 is the structural representation of the load voltage testing circuit of the utility model first embodiment;
Fig. 2 is the structural representation of wherein a kind of voltage detecting circuit of the utility model embodiment;
Fig. 3 and Fig. 4 is the voltage and current waveform of the utility model embodiment;
Fig. 5 is the structural representation of the another kind of voltage detecting circuit of the utility model embodiment;
Fig. 6 is the structural representation of the load voltage testing circuit of the utility model second embodiment;
Fig. 7 is the structural representation of the load voltage testing circuit of the utility model the 3rd embodiment.
Embodiment
Below in conjunction with accompanying drawing, by specific embodiment, clear, complete description is carried out to the technical solution of the utility model.
Please refer to Fig. 1, for a kind of load voltage testing circuit of the utility model embodiment, comprise: load power source circuit 14, divider resistance 16, switching circuit 15 and voltage detecting circuit 18, one end of described load power source circuit 14 is connected with operating voltage input Vin, the other end of described load power source circuit 14 and the first end of switching circuit 15, the first end of divider resistance 16 is connected, second end of described divider resistance 16 is together with the second end ground connection of described switching circuit 15, described switching circuit 15 is utilized to control for load voltage, point pressure side of described divider resistance 16 is connected with the signal input part of voltage detecting circuit 18, described voltage detecting circuit 18 keeps by sampling point pressure side feedback voltage obtaining divider resistance 16, and obtain load voltage by computing.
In the present embodiment, described load power source circuit 14 comprises diode 13, inductance 12 and load 11, one end of described load 11, the negative pole of diode 13 are connected with operating voltage input Vin, the other end of described load 11 is connected with one end of inductance 12, and the other end of described inductance 12 is connected with the positive pole of diode 13 and is connected with the first end of switching circuit 15, the first end of divider resistance 16.
In the present embodiment, described load 11 is LED, and described diode 13 is consistent with the direction of LED.For preventing load open circuit from causing damage or formation potential safety hazard to other device, need to detect load voltage.
In other embodiments, described load can also be other electricity devices, utilizes the voltage of described voltage detecting circuit to load to detect.
Also be connected with the first electric capacity C1 between described operating voltage input Vin and earth terminal, described first electric capacity is stablizing in order to maintenance work voltage.In other embodiments, described load two ends are also parallel with the second electric capacity, and described second electric capacity is used for carrying out filtering to the electric current flowing to load.
In the present embodiment, described switching circuit 15 is switching tube, and the first end of described switching tube is connected with the other end of load power source circuit 14, and the second end ground connection of described switching tube, the control end of described switching tube is connected with load control circuit 17.
In the present embodiment, described switching tube is MOS transistor.In other embodiments, described switching tube can also be other switching devices such as triode.
In the present embodiment, described divider resistance 16 comprises the first divider resistance R1 and the second divider resistance R2, utilize described first divider resistance R1 and the second divider resistance R2 that the voltage at switching tube 15 two ends is carried out dividing potential drop, utilize point pressure side between the first divider resistance R1 and the second divider resistance R2 to be connected with the signal input part of voltage detecting circuit 18.
In other embodiments, described divider resistance also can be a resistance, and point pressure side of divider resistance is connected with the signal input part of voltage detecting circuit.
In the present embodiment, please refer to Fig. 2, described voltage detecting circuit 18 comprises signal input part 81, sampling keeps module 83, first reference voltage module 84, averaging module 82 and subtracter 85, described sampling keeps module 83 to be connected with the first reference voltage module 84, and described sampling keeps one end of module 83 to be connected with signal input part 81, one end of described first reference voltage module 84 is as the first input end of subtracter 85, one end of described averaging module 82 is connected with signal input part 81, and the other end is as the second input of subtracter 85.
When circuit working is in continuous current mode or critical continuous mode current-mode, described continuous current mode refers to during diode continuousing flow, inductive current declines and not yet reaches zero, namely carry out next switch periods, inductive current remain always on the occasion of, during described critical continuous mode current-mode refers to diode continuousing flow, inductive current drops to when zero, carry out next switch periods immediately, inductive current has a point to be zero in each cycle, point pressure side feedback voltage V
fBwaveform as shown in Figure 3, wherein K=R2/ (R1+R2).When switching tube 15 is opened, V
fB=0; When switching tube 15 turns off, and inductive current be on the occasion of time, diode 13 conducting, ignores the conduction voltage drop of diode, V
fB=K*Vin.The time scale of switching tube conducting is D, and the time scale of diode current flow is D '=(1-D).Divide the mean value V of pressure side feedback voltage waveform
fB_AVG=K* (Vin-V
lED), wherein V
lEDfor the voltage of load LED.
When circuit working is in discontinuous current mode, during described discontinuous current mode refers to diode continuousing flow, inductive current drops to zero, and after a period of time, just carry out next switch periods, inductive current is zero in each cycle for some time, point pressure side feedback voltage V
fBwaveform as shown in Figure 4: turn off at switching tube 15, and inductive current be on the occasion of time, diode 13 conducting, ignores the conduction voltage drop of diode, V
fB=K*Vin; In diode 13 conduction period, inductive current declines gradually, and when inductive current drops to 0, diode 13 automatically shuts down, and the voltage of inductance second end starts to decline, point pressure side feedback voltage V
fBdecline with the voltage in proportion of inductance second end.When a point pressure side feedback voltage V being detected
fBlower than voltage during diode current flow, inductive current zero crossing can be judged as.Due to the parasitic capacitance of the inductance in circuit and switching tube/diode, LC loop can be formed, when loop underdamping, will vibrate, therefore when circuit working is in discontinuous current mode, point pressure side feedback voltage V
fBwaveform may have vibration, please refer to Fig. 4, but no matter divides pressure side feedback voltage V
fBhow concrete, its mean value remains V
fBA=K* (Vin-V
lED), namely the mean value of the first end voltage of divider resistance 16 all meets V
aVG=Vin-V
lED.
When the diode conducts, to a point pressure side feedback voltage V
fBcarry out sampling to keep obtaining V
fBS=K*Vin, the sampled voltage of the first end of divider resistance 16 is Vin.With lower than V
fBSa certain voltage V2 is the benchmark of subtracter 85, and point pressure side feedback voltage V
fBa point pressure side feedback voltage V is obtained by an averaging module
fBmean value V
fBAcompare.When a point pressure side feedback voltage V
fBmean value V
fBAequal (V
fBS-V2) time, subtracter 85 overturns, K*Vin-V2=V
fBA=K* (Vin-V
lED), i.e. V2=K*V
lED.Described V
lEDbe the voltage limiting value of LED.
No matter circuit working is in continuous current mode, critical continuous mode current-mode or discontinuous current mode, and the mean value of the first end voltage of divider resistance 16 all meets V
aVG=Vin-V
lED.As long as to point pressure side feedback voltage V during diode current flow
fB=K*Vin carries out sampling and keeps, and deducts a point pressure side feedback voltage V
fBmean value can obtain the voltage K*Vin-K* (Vin-V of LED
lED)=K*V
lED.
In the present embodiment, voltage detecting circuit 18 is arranged in same load control circuit 17 or control chip, when load voltage overvoltage being detected, utilizes the control end Vc closing switch pipe 15 of switching tube.
In the present embodiment, the control end of described voltage detecting circuit and switching tube also can be arranged in different control chips or load control circuit.
Because order that is average and addition and subtraction does not affect result, also the voltage of the first end of above-mentioned kept divider resistance can be deducted the first end real-time voltage of divider resistance, then this difference voltage is averaged, obtain load voltage.Thus in other embodiments, another kind of voltage detecting circuit please refer to Fig. 5, comprise: signal input part 91, sampling keep module 93, averaging module 92 and subtracter 94, described sampling keeps module 93 to be connected with subtracter 94, and described sampling keeps one end of module 93 to be connected with signal input part 91, the other end of described subtracter 94 is connected with signal input part 91, the input of described averaging module 92 is connected with the output of subtracter 94, and the output of averaging module 92 is exactly the output of institute's detectable voltage signals.
The utility model second embodiment still provides another kind of load voltage testing circuit, please refer to Fig. 6, remainder is all identical, only have load power source circuit not identical, described load power source circuit 29 comprises: Transformer Winding 24, diode 22 and load 21, described load 21 one end is connected with the negative pole of diode 22, described load 21 other end is connected with one end of Transformer Winding 24 secondary, the other end of described Transformer Winding 24 secondary is connected with the positive pole of diode 22, the one end on the described former limit of Transformer Winding 24 is connected with operating voltage input Vin, the described other end on the former limit of Transformer Winding 24 and the first end of switching circuit 15, the first end of divider resistance 16 is connected.In other embodiments, described load two ends are also parallel with the second electric capacity, and described second electric capacity is used for carrying out filtering to the electric current flowing to load.
When diode 22 conducting, the voltage of the first end of divider resistance 16 is Vin+n*Vo, Vo is exactly output voltage, i.e. LED electrical pressure, and n is transformer turns ratio.No matter circuit working is in continuous current mode, critical continuous mode current-mode or discontinuous current mode, and the average electrical pressure reduction due to inductance two ends is zero, and the first end average voltage of divider resistance 16 all meets V
aVG=Vin.
As long as carry out sampling to the first end voltage Vin+n*Vo of the divider resistance 16 during diode current flow to keep, the mean value deducting the first end voltage of divider resistance 16 can obtain the voltage Vin+n*Vo-Vin=n*Vo of load.
Or, keep as long as carry out sampling to the first end voltage Vin+n*Vo of the divider resistance 16 during diode current flow, deduct the instantaneous value of the first end voltage of divider resistance 16, then be averaged and can obtain the voltage Vin+n*Vo-Vin=n*Vo of load.
The utility model the 3rd embodiment still provides another kind of load voltage testing circuit, please refer to Fig. 7, remainder is all identical, only have load power source circuit not identical, described load power source circuit 34 comprises: diode 33, inductance 32 and load 31, one end of described load 31, one end of inductance 32 is connected with operating voltage input Vin, the other end of described load 31 is connected with negative pole one end of diode 33, positive pole one end of described diode 33 be connected with the other end of inductance 32 and with the first end of switching circuit 15, the first end of divider resistance 16 is connected.In other embodiments, described load two ends are also parallel with the second electric capacity, and described second electric capacity is used for carrying out filtering to the electric current flowing to load.
When diode 33 conducting, the voltage of the first end of divider resistance 16 is Vin+Vo.No matter circuit working is in continuous current mode, critical continuous mode current-mode or discontinuous current mode, and the first end average voltage of divider resistance 16 all meets V
aVG=Vin.
As long as carry out sampling to the first end voltage Vin+Vo of the divider resistance 16 during diode current flow to keep, the mean value deducting the first end voltage of divider resistance 16 can obtain the voltage Vin+Vo-Vin=Vo of load.
Or, keep as long as carry out sampling to the first end voltage Vin+Vo of the divider resistance 16 during diode current flow, deduct the instantaneous value of the first end voltage of divider resistance 16, then be averaged and can obtain the voltage Vin+Vo-Vin=Vo of load.
Based on above-mentioned load voltage testing circuit, the utility model embodiment still provides a kind of load voltage detection method, comprising:
Divider resistance is utilized to gather the voltage waveform of the first end of divider resistance;
When the diode conducts, sampling keeps the voltage of the first end of divider resistance, the voltage of the first end of kept divider resistance is deducted the mean value of the first end voltage of divider resistance, obtains load voltage; Or the voltage of the first end of kept divider resistance is deducted the first end real-time voltage of divider resistance, then this difference voltage is averaged, obtain load voltage.
In the utility model first embodiment, because the mean value of the first end voltage of divider resistance 16 all meets V
aVG=Vin-V
lED.As long as to point pressure side feedback voltage V during diode current flow
fB=K*Vin carries out sampling and keeps, and deducts a point pressure side feedback voltage V
fBmean value can obtain the voltage K*Vin-K* (Vin-V of LED
lED)=K*V
lED.
Or, as long as to point pressure side feedback voltage V during diode current flow
fB=K*Vin carries out sampling and keeps, and deducts a point pressure side feedback voltage V
fBinstantaneous value, then be averaged and can obtain the voltage K*Vin-K* (Vin-V of LED
lED)=K*V
lED.
In the utility model second embodiment, no matter circuit working is in continuous current mode, critical continuous mode current-mode or discontinuous current mode, and the first end average voltage of divider resistance 16 all meets V
aVG=Vin.Carry out sampling to the first end voltage Vin+n*Vo of the divider resistance 16 during diode current flow to keep, the mean value deducting the first end voltage of divider resistance 16 can obtain the voltage Vin+n*Vo-Vin=n*Vo of load.
Or, sampling is carried out to the first end voltage Vin+n*Vo of the divider resistance 16 during diode current flow and keeps, deduct the instantaneous value of the first end voltage of divider resistance 16, then be averaged and can obtain the voltage Vin+n*Vo-Vin=n*Vo of load.
In the utility model the 3rd embodiment, no matter circuit working is in continuous current mode, critical continuous mode current-mode or discontinuous current mode, and the first end average voltage of divider resistance 16 all meets V
aVG=Vin.Carry out sampling to the first end voltage Vin+Vo of the divider resistance 16 during diode current flow to keep, the mean value deducting the first end voltage of divider resistance 16 can obtain the voltage Vin+Vo-Vin=Vo of load.
Or, sampling is carried out to the first end voltage Vin+Vo of the divider resistance 16 during diode current flow and keeps, deduct the instantaneous value of the first end voltage of divider resistance 16, then be averaged and can obtain the voltage Vin+Vo-Vin=Vo of load.
Although the utility model with preferred embodiment openly as above; but it is not for limiting the utility model; any those skilled in the art are not departing from spirit and scope of the present utility model; the Method and Technology content of above-mentioned announcement can be utilized to make possible variation and amendment to technical solutions of the utility model; therefore; every content not departing from technical solutions of the utility model; the any simple modification done above embodiment according to technical spirit of the present utility model, equivalent variations and modification, all belong to the protection range of technical solutions of the utility model.
Claims (10)
1. a load voltage testing circuit, it is characterized in that, comprise: load power source circuit, divider resistance, switching circuit and voltage detecting circuit, described load power source circuit comprises load, diode and inductance, and described load, diode and inductance series connection form loop circuit, one end of described load power source circuit is connected with operating voltage input, the described other end of load power source circuit and the first end of switching circuit, the first end of divider resistance is connected, second end of described divider resistance is together with the second end ground connection of described switching circuit, described switching circuit is utilized to control for load voltage, point pressure side of described divider resistance is connected with the signal input part of voltage detecting circuit, described voltage detecting circuit keeps by sampling point pressure side feedback voltage obtaining divider resistance, and obtain load voltage by computing.
2. load voltage testing circuit as claimed in claim 1, it is characterized in that, described voltage detecting circuit comprises signal input part, sampling keeps module, the first reference voltage module, averaging module and subtracter, described sampling keeps module to be connected with the first reference voltage module, and described sampling keeps one end of module to be connected with signal input part, one end of described first reference voltage module is as the first input end of subtracter, one end of described averaging module is connected with signal input part, and the other end is as the second input of subtracter.
3. load voltage testing circuit as claimed in claim 1, it is characterized in that, described voltage detecting circuit comprises signal input part, sampling keeps module, averaging module and subtracter, described sampling keeps module to be connected with subtracter, and described sampling keeps one end of module to be connected with signal input part, the other end of described subtracter is connected with signal input part, the input of described averaging module is connected with the output of subtracter, and the output of averaging module is exactly the output of institute's detectable voltage signals.
4. load voltage testing circuit as claimed in claim 1, it is characterized in that, described switching circuit is switching tube, and the first end of described switching tube is connected with the other end of load power source circuit, second end ground connection of described switching tube, the control end of described switching tube is connected with load control circuit.
5. load voltage testing circuit as claimed in claim 3, it is characterized in that, described voltage detecting circuit is arranged in load control circuit, when load voltage overvoltage being detected, utilizes the control end on-off switching tube of switching tube.
6. load voltage testing circuit as claimed in claim 1, it is characterized in that, described load is LED.
7. load voltage testing circuit as claimed in claim 1, it is characterized in that, described load power source circuit comprises: diode, inductance and load, one end of described load, the negative pole of diode are connected with operating voltage input, the other end of described load is connected with one end of inductance, and the other end of described inductance is connected with the positive pole of diode and is connected with the first end of switching circuit, the first end of divider resistance.
8. load voltage testing circuit as claimed in claim 1, it is characterized in that, described load power source circuit comprises: Transformer Winding, diode and load, described load one end is connected with the negative pole of diode, the described load other end is connected with one end of Transformer Winding secondary, the described other end of Transformer Winding secondary is connected with the positive pole of diode, the one end on the former limit of described Transformer Winding is connected with operating voltage input, and the other end on the former limit of described Transformer Winding is connected with the first end of switching circuit, the first end of divider resistance.
9. load voltage testing circuit as claimed in claim 1, it is characterized in that, described load power source circuit comprises: diode, inductance and load, one end of described load, one end of inductance are connected with operating voltage input, the other end of described load is connected with negative pole one end of diode, and positive pole one end of described diode is connected with the other end of inductance and is connected with the first end of switching circuit, the first end of divider resistance.
10. the load voltage testing circuit as described in claim 1,7,8,9 any one, is characterized in that, described load power source circuit also comprises second electric capacity in parallel with load.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN201420634921.9U CN204157132U (en) | 2014-10-29 | 2014-10-29 | Load voltage testing circuit |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN201420634921.9U CN204157132U (en) | 2014-10-29 | 2014-10-29 | Load voltage testing circuit |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| CN204157132U true CN204157132U (en) | 2015-02-11 |
Family
ID=52515217
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CN201420634921.9U Withdrawn - After Issue CN204157132U (en) | 2014-10-29 | 2014-10-29 | Load voltage testing circuit |
Country Status (1)
| Country | Link |
|---|---|
| CN (1) | CN204157132U (en) |
Cited By (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN104519644A (en) * | 2014-10-29 | 2015-04-15 | 杰华特微电子（杭州）有限公司 | Load voltage detecting circuit and corresponding load voltage detecting method |
| CN108100303A (en) * | 2017-12-20 | 2018-06-01 | 贵州航天电子科技有限公司 | A kind of insurance detection circuit |
-
2014
- 2014-10-29 CN CN201420634921.9U patent/CN204157132U/en not_active Withdrawn - After Issue
Cited By (3)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN104519644A (en) * | 2014-10-29 | 2015-04-15 | 杰华特微电子（杭州）有限公司 | Load voltage detecting circuit and corresponding load voltage detecting method |
| CN104519644B (en) * | 2014-10-29 | 2018-02-16 | 杰华特微电子（杭州）有限公司 | Load voltage detects circuit and corresponding load voltage detection method |
| CN108100303A (en) * | 2017-12-20 | 2018-06-01 | 贵州航天电子科技有限公司 | A kind of insurance detection circuit |
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| Date | Code | Title | Description |
|---|---|---|---|
| C14 | Grant of patent or utility model | ||
| GR01 | Patent grant | ||
| AV01 | Patent right actively abandoned | ||
| AV01 | Patent right actively abandoned |
Granted publication date: 20150211 Effective date of abandoning: 20180216 |