CN203691707U - LED load voltage detection circuit - Google Patents
LED load voltage detection circuit Download PDFInfo
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- CN203691707U CN203691707U CN201420015189.7U CN201420015189U CN203691707U CN 203691707 U CN203691707 U CN 203691707U CN 201420015189 U CN201420015189 U CN 201420015189U CN 203691707 U CN203691707 U CN 203691707U
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- Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
- Y02—TECHNOLOGIES OR APPLICATIONS FOR MITIGATION OR ADAPTATION AGAINST CLIMATE CHANGE
- Y02B—CLIMATE CHANGE MITIGATION TECHNOLOGIES RELATED TO BUILDINGS, e.g. HOUSING, HOUSE APPLIANCES OR RELATED END-USER APPLICATIONS
- Y02B20/00—Energy efficient lighting technologies, e.g. halogen lamps or gas discharge lamps
- Y02B20/40—Control techniques providing energy savings, e.g. smart controller or presence detection
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Abstract
The utility model discloses an LED load voltage detection circuit. The circuit comprises a voltage dividing unit and a turn-off control unit. The voltage dividing unit is connected to the turn-off control unit. The voltage dividing unit carries out voltage dividing detection of the voltage of an LED load. The turn-off control unit turns off the LED load according to a low level PWM signal, so as to fully turn off the LED load, and prevent problems that a small current generated when the LED lamp is turned off makes the LED lamp slightly bright to lead to inaccurate detection results. The circuit improves accuracy of detection results.
Description
Technical field
The utility model relates to LED load detecting technical field, particularly a kind of LED 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 actually rare in the design of the function aspects such as output overloading, underload protection, its reason is that the detection of LED load is more difficult.Common LED load detecting circuit can only detect the voltage of LED load, and actual detection is subject to other effect of signals often, causes testing result not obvious, fall flat, and the particularly LED driving power of High voltage output, impact is more serious like this.
Existing LED load voltage testing circuit as shown in Figure 1, it comprises the first resistance R 1, the second resistance R 2, the 3rd resistance R 3, switching tube V1, inductance L A, the first capacitor C 1 and the second capacitor C 2, described switching tube V1 is NMOS pipe, the control end (being the grid of NMOS pipe) of switching tube V1 connects brightness adjustment control end PWM, the first link (being the drain electrode of NMOS pipe) of switching tube V1 connects the different name end of inductance, the anodal LED+ of power end Vbus and LED lamp, the second link (being the source electrode of NMOS pipe) of switching tube V1 is by the 3rd resistance R 3 ground connection, the Same Name of Ends of described inductance L A connects the negative pole LED-of LED lamp, also connect the anodal LED+ of power end and LED lamp by the first capacitor C 1, also connect one end of the second resistance R 2, the other end of described the second resistance R 2 connects voltage detecting end Vtest, also connect by the first resistance R 1 ground, the second capacitor C 2 is in parallel with the first resistance R 1.
Because the voltage of power end Vbus input is more stable, can detect the negative terminal (being the negative pole of LED lamp) of LED load, carry out dividing potential drop by the first resistance R 1 and the second resistance R 2, can obtain the voltage Vled of LED load, adopt following formula:
Because the magnitude of voltage on voltage detecting end Vtest can obtain by the AD sampling of single-chip microcomputer or other IC, then can obtain the voltage Vled of LED load in conjunction with above-mentioned formula.But this circuit scope of application is narrower, particularly drive for the LED of light modulation type, it is affected by pwm signal while detection, cause testing result not obvious.As can be seen from Figure 1, in the time that pwm signal (PWM inputs by brightness adjustment control end) is low level, switching tube V1 is in open mode (disconnecting), and the output of LED should be unsettled due to the disconnection of switching tube V1, and LED lamp should be the state extinguishing.But due to the existence of the first resistance R 1 and the second resistance R 2, in the time that pwm signal is 0, in LED load, also have a current circuit, pass through " LED load → the second resistance R 2 → the first resistance R 1 → ground ", causing at PWM is still to produce little electric current at 0 o'clock, LED load is not turned off completely, still, in micro-luminous state, particularly, in the situation that ambient light is darker, can find out that its brightness is more obvious.Certainly will exert an influence to the voltage Vled of LED load in this case, cause testing result inaccurate.
Thereby prior art need to improve.
Utility model content
In view of above-mentioned the deficiencies in the prior art part, the purpose of this utility model is to provide a kind of LED load voltage testing circuit, still produces little electric current during as low level and causes the inaccurate problem of testing result to solve existing LED load voltage testing circuit at pwm signal.
In order to achieve the above object, the utility model has been taked following technical scheme:
A kind of LED load voltage testing circuit, it comprises:
For the partial pressure unit that LED load voltage is carried out to dividing potential drop detection;
For according to low level pwm signal to LED load turn-offs processing shutoff control unit;
Described partial pressure unit connects turn-offs control unit.
Described LED load voltage testing circuit, wherein, described partial pressure unit comprises the first resistance, the second resistance, the 3rd resistance, switching tube, inductance, the first electric capacity and the second electric capacity; Described switching tube is NMOS pipe, the control end of switching tube connects brightness adjustment control end, the first link of switching tube connects the positive pole of different name end, power end and the LED lamp of inductance, the second link of switching tube is by the 3rd grounding through resistance, the Same Name of Ends of described inductance connects the negative pole of LED lamp, is also connected power end and the positive pole of LED lamp, is also connected one end of the second resistance by the first electric capacity, the other end of described the second resistance connect voltage detecting end, also by the first resistance connect, the second electric capacity is in parallel with the first resistance.
Described LED load voltage testing circuit, wherein, described shutoff control unit comprises the first triode, the second triode, the 4th resistance and the 5th resistance, the base stage of described the first triode connects one end of collector electrode and the 4th resistance of the second triode, the emitter of the first triode connects the positive pole of power end and LED lamp, the collector electrode of the first triode connects the negative pole of LED lamp and the Same Name of Ends of inductance, the base stage of described the second triode connects fault control end, the emitter of the second triode connects one end of the 5th resistance, the other end ground connection of the 5th resistance, the other end of described the 4th resistance connects the positive pole of power end and LED lamp.
Described LED load voltage testing circuit, wherein, described the first triode is PNP triode, the second triode is NPN triode.
Described LED load voltage testing circuit, wherein, described shutoff control unit comprises optocoupler, the 1st end of described optocoupler connects fault control end, its 2nd end ground connection, its 3rd end connects voltage detecting end, and its 4th end connects the other end of the second resistance.
Compared to prior art, a kind of LED load voltage testing circuit that the utility model provides, while LED load voltage being carried out to dividing potential drop detection by partial pressure unit, by turn-off control unit according to low level pwm signal to LED load turn-off processing, LED load is turned off completely, thereby while avoiding LED lamp to close, produce little electric current and make its glimmer, cause the inaccurate problem of testing result; Improve the accuracy of testing result.
Brief description of the drawings
Fig. 1 is the circuit diagram of existing LED load voltage testing circuit.
Fig. 2 is the circuit diagram of the utility model LED load voltage testing circuit embodiment mono-.
Fig. 3 is the circuit diagram of the utility model LED load voltage testing circuit embodiment bis-.
Embodiment
The utility model provides a kind of LED load voltage testing circuit, in the time that pwm signal is low level (being 0V), control LED load short circuits or disconnect with ground, thereby LED load is turn-offed completely, when LED lamp is closed, no longer produce little electric current, improve the accuracy of LED load voltage testing result.
For making the purpose of this utility model, technical scheme and effect clearer, clear and definite, referring to the accompanying drawing embodiment that develops simultaneously, the utility model is further described.Should be appreciated that specific embodiment described herein is only in order to explain the utility model, and be not used in restriction the utility model.
Refer to Fig. 2, the LED load voltage testing circuit that the utility model provides comprises partial pressure unit 100 and turn-offs control unit 200, described partial pressure unit 100 connection shutoff control units 200.Partial pressure unit 100 is carried out dividing potential drop detection to LED load voltage, turn-off control unit 200 according to low level pwm signal to LED load turn-off processing, LED load is turned off completely, makes its glimmer thereby produce little electric current while avoiding LED lamp to close, cause the inaccurate problem of testing result; Improve the accuracy of testing result.
Wherein, described partial pressure unit 100 comprises the first resistance R 1, the second resistance R 2, the 3rd resistance R 3, switching tube V1, inductance L A, the first capacitor C 1 and the second capacitor C 2, described switching tube V1 is NMOS pipe, the control end (being the grid of NMOS pipe) of switching tube V1 connects brightness adjustment control end PWM, the first link (being the drain electrode of NMOS pipe) of switching tube V1 connects the different name end of inductance L A, the anodal LED+ of power end Vbus and LED lamp, the second link (being the source electrode of NMOS pipe) of switching tube V1 is by the 3rd resistance R 3 ground connection, the Same Name of Ends of described inductance L A connects the negative pole LED-of LED lamp, also connect the anodal LED+ of power end Vbus and LED lamp by the first capacitor C 1, also connect one end of the second resistance R 2, the other end of described the second resistance R 2 connects voltage detecting end Vtest, also connect by the first resistance R 1 ground, the second capacitor C 2 is connected between voltage detecting end Vtest and ground.
Described shutoff control unit 200 comprises the first triode Q1, the second triode Q2, the 4th resistance R 4 and the 5th resistance R 5, the base stage of described the first triode Q1 connects the collector electrode of the second triode Q2 and one end of the 4th resistance R 4, the emitter of the first triode Q1 connects the anodal LED+ of power end Vbus and LED lamp, the collector electrode of the first triode Q1 connects the negative pole LED-of LED lamp and the Same Name of Ends of inductance L A, the base stage of described the second triode Q2 connects fault control end ON/OFF, the emitter of the second triode Q2 connects one end of the 5th resistance R 5, the other end ground connection of the 5th resistance R 5, the other end of described the 4th resistance R 4 connects the anodal LED+ of power end Vbus and LED lamp.
When concrete enforcement, described the first triode Q1 is PNP triode, and the second triode Q2 is NPN triode, and the first triode Q1 and the second triode Q2 all high pressure resistant.In the time that the pwm signal of brightness adjustment control end PWM input is not 0V, fault control end ON/OFF inputs a low level control signal, the second not conducting of triode Q2 causes the first also not conducting of triode Q1, and the light modulation of whole circuit and LED load detecting function are normally carried out.In the time that the pwm signal of input is 0V, the control signal of a high level of fault control end ON/OFF input makes the second triode Q2 conducting, controls the first also conducting of triode Q1.Now, LED load, in Fig. 2 between the anodal LED+ of LED lamp and its negative pole LED-by the first triode Q1 short circuit, can avoid like this electric current to flow through LED load, make the LED lamp can be in glimmer state, be equivalent to make LED load to be turned off completely, improved the accuracy of testing result.Described the 5th resistance R 5 can make the first triode Q1 conducting as early as possible, and keeps the stability of its conducting state.
In order to simplify the use of circuit, minimizing electronic component, reduce cost, the present embodiment is improved further above-mentioned shutoff control unit 200, and the LED load voltage testing circuit of embodiment bis-is provided, and its circuit structure is as shown in Figure 3.Owing to partial pressure unit 100 not being changed, at Fig. 3 with label 200
/represent the shutoff control unit after improving.Described shutoff control unit 200
/comprise optocoupler OPI, the 1st end (being the positive pole of light-emitting diode) of described optocoupler OPI connects fault control end ON/OFF, its the 2nd end (being the negative pole of light-emitting diode) ground connection, its the 3rd end (being the emitter of photosensitive triode) connects voltage detecting end Vtest, and its 4th end (being the collector electrode of photosensitive triode) connects the other end of the second resistance R 2.
In the time that the pwm signal of brightness adjustment control end PWM input is not 0V, the control signal of a high level of fault control end ON/OFF input, thereby lumination of light emitting diode makes photosensitive triode conducting, optocoupler OPI conducting, the light modulation of whole circuit and LED load detecting function are normally carried out.In the time that the pwm signal of input is 0V, fault control end ON/OFF inputs a low level control signal, thereby light-emitting diode is not luminous, photosensitive triode is ended, between the second resistance R 2 and the first resistance R 1, disconnect, be equivalent to make open circuit between the negative pole LED-of LED lamp and ground, now, LED load does not have current circuit, LED load is turned off completely, the situation of LED load glimmer can not occur equally, improved the accuracy of testing result.
Should be understood that, the main triode break-make mode that adopts of embodiment mono-is controlled LED load short circuits, thereby LED load is turned off completely.Embodiment bis-adopts optocoupler break-make mode to control LED load cut-off, owing to only using a common optocoupler in embodiment bis-, without using the high high-voltage three-pole pipe (i.e. the first triode Q1, the second triode Q2) of price in embodiment mono-to carry out short circuit to LED load, its cost is lower, and circuit structure is simpler.
In sum, a kind of LED load voltage testing circuit that the utility model provides, while LED load voltage being carried out to dividing potential drop detection by partial pressure unit, by turn-off control unit according to low level pwm signal to LED load turn-off processing, adopt triode break-make mode to control LED load short circuits, or adopt optocoupler break-make mode to control LED load cut-off, LED load is turned off completely, thereby while avoiding LED lamp to close, produce little electric current and make its glimmer, cause the inaccurate problem of testing result; Improve the accuracy of testing result.
Be understandable that; for those of ordinary skills; can be equal to replacement or change according to the technical solution of the utility model and utility model design thereof, and all these changes or replacement all should belong to the protection range of the appended claim of the utility model.
Claims (5)
1. a LED load voltage testing circuit, is characterized in that, comprising:
For the partial pressure unit that LED load voltage is carried out to dividing potential drop detection;
For according to low level pwm signal to LED load turn-offs processing shutoff control unit;
Described partial pressure unit connects turn-offs control unit.
2. LED load voltage testing circuit according to claim 1, is characterized in that, described partial pressure unit comprises the first resistance, the second resistance, the 3rd resistance, switching tube, inductance, the first electric capacity and the second electric capacity; Described switching tube is NMOS pipe, the control end of switching tube connects brightness adjustment control end, the first link of switching tube connects the positive pole of different name end, power end and the LED lamp of inductance, the second link of switching tube is by the 3rd grounding through resistance, the Same Name of Ends of described inductance connects the negative pole of LED lamp, is also connected power end and the positive pole of LED lamp, is also connected one end of the second resistance by the first electric capacity, the other end of described the second resistance connect voltage detecting end, also by the first resistance connect, the second electric capacity is in parallel with the first resistance.
3. LED load voltage testing circuit according to claim 2, it is characterized in that, described shutoff control unit comprises the first triode, the second triode, the 4th resistance and the 5th resistance, the base stage of described the first triode connects one end of collector electrode and the 4th resistance of the second triode, the emitter of the first triode connects the positive pole of power end and LED lamp, the collector electrode of the first triode connects the negative pole of LED lamp and the Same Name of Ends of inductance, the base stage of described the second triode connects fault control end, the emitter of the second triode connects the 5th resistance one end, the other end of the 5th resistance connects ground, the other end of described the 4th resistance connects the positive pole of power end and LED lamp.
4. LED load voltage testing circuit according to claim 3, is characterized in that, described the first triode is PNP triode, and the second triode is NPN triode.
5. LED load voltage testing circuit according to claim 2, is characterized in that, described shutoff control unit comprises optocoupler, the 1st end of described optocoupler connects fault control end, its the 2nd end ground connection, its 3rd end connects voltage detecting end, and its 4th end connects the other end of the second resistance.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN201420015189.7U CN203691707U (en) | 2014-01-10 | 2014-01-10 | LED load voltage detection circuit |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN201420015189.7U CN203691707U (en) | 2014-01-10 | 2014-01-10 | LED load voltage detection circuit |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| CN203691707U true CN203691707U (en) | 2014-07-02 |
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| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CN201420015189.7U Expired - Fee Related CN203691707U (en) | 2014-01-10 | 2014-01-10 | LED load voltage detection circuit |
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| Country | Link |
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| CN (1) | CN203691707U (en) |
Cited By (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN110461061A (en) * | 2019-08-12 | 2019-11-15 | 天津华来科技有限公司 | A kind of single live wire power getting circuit controlled based on microswitch or optocoupler |
| CN110456701A (en) * | 2019-08-12 | 2019-11-15 | 天津华来科技有限公司 | A kind of battery-based intelligent wireless wall switch device |
-
2014
- 2014-01-10 CN CN201420015189.7U patent/CN203691707U/en not_active Expired - Fee Related
Cited By (3)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN110461061A (en) * | 2019-08-12 | 2019-11-15 | 天津华来科技有限公司 | A kind of single live wire power getting circuit controlled based on microswitch or optocoupler |
| CN110456701A (en) * | 2019-08-12 | 2019-11-15 | 天津华来科技有限公司 | A kind of battery-based intelligent wireless wall switch device |
| CN110461061B (en) * | 2019-08-12 | 2024-04-09 | 天津华来科技股份有限公司 | Single-live wire circuit based on micro switch or optocoupler control |
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| Date | Code | Title | Description |
|---|---|---|---|
| C14 | Grant of patent or utility model | ||
| GR01 | Patent grant | ||
| CF01 | Termination of patent right due to non-payment of annual fee |
Granted publication date: 20140702 Termination date: 20220110 |
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| CF01 | Termination of patent right due to non-payment of annual fee |