CN220273914U - PWM dimming short-circuit protection circuit and lamp - Google Patents
PWM dimming short-circuit protection circuit and lamp Download PDFInfo
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- CN220273914U CN220273914U CN202321910176.1U CN202321910176U CN220273914U CN 220273914 U CN220273914 U CN 220273914U CN 202321910176 U CN202321910176 U CN 202321910176U CN 220273914 U CN220273914 U CN 220273914U
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Abstract
The application discloses a PWM dimming short-circuit protection circuit and a lamp, which relate to the field of LED dimming, and comprise a control module, a dimming module, a protection module and a bias module, wherein the second end of the dimming module is connected with a power supply, the first end of the dimming module is connected with the bias module, and the third end of the dimming module is connected with an LED light source; the bias module comprises an input end and two output ends, the input end of the bias module is connected with a power supply, the first output end of the bias module is connected with the first end of the dimming module, and the second output end of the bias module is connected with the control module; the first end of the control module receives the PWM signal, the second end of the control module is grounded, and the third end of the control module is connected with the second output end of the bias module; the input end of the protection module is connected with the first end of the control module, and the output end of the protection module is connected with the third end of the dimming module and the LED light source. When the load is short-circuited, the dimming module is protected from the impact of high current so as not to damage devices.
Description
Technical Field
The utility model relates to the technical field of LED dimming, in particular to a PWM dimming short-circuit protection circuit and a lamp.
Background
PWM dimming is one of the dominant dimming techniques in LED dimming. The PWM dimming precision is high, the dimming range is large, the dimming is colorless, the circuit is simple, and the application is wider.
Referring to fig. 1, in the PWM dimming circuit commonly used at present, the on time of the LED light source load is controlled by the on time of the NMOS tube, so as to achieve the dimming effect, and the PWM dimming circuit is simple to use and has a large dimming range. However, when the LED light source load has short circuit fault, the input voltage is fully applied to the NMOS tube, the on-resistance of the NMOS tube is small, and a great impact current is generated to damage the NMOS tube.
Accordingly, there is a need for improvement and development in the art.
Disclosure of Invention
The technical problem to be solved by the application is to the defects of the prior art, and the PWM dimming short-circuit protection circuit and the lamp are provided, so that the problem that an LED light source load causes a great impact current when a short-circuit fault occurs in the prior art, and therefore an MOS tube is damaged is solved.
In a first aspect, the present application provides a PWM dimming short-circuit protection circuit, which adopts the following technical scheme:
a PWM dimming short circuit protection circuit, comprising: the device comprises a control module, a dimming module, a protection module and a bias module, wherein,
the second end of the dimming module is connected with a power supply, the first end of the dimming module is connected with the biasing module, and the third end of the dimming module is connected with an LED light source;
the bias module comprises an input end and two output ends, wherein the input end of the bias module is connected with a power supply, the first output end of the bias module is connected with the first end of the dimming module, and the second output end of the bias module is connected with the control module;
the first end of the control module receives a PWM signal, the second end of the control module is grounded, the third end of the control module is connected with the second output end of the bias module, and the control module is used for controlling the dimming module to dim the LED light source;
the input end of the protection module is connected with the first end of the control module, the output end of the protection module is connected with the third end of the dimming module and the LED light source, and the protection module is used for protecting the control module in case of short circuit fault.
By adopting the technical scheme, when the circuit works normally, the PWM signal output is low, the control module is not conducted, the dimming module is also closed, and the LED light source load does not work; when the PWM signal output is high, the control module is conducted, the dimming module also works normally, and at the moment, the control module controls the dimming module to dim the LED light source load. When the LED light source load has a short circuit fault, the PWM signal output is low, the control module cannot be conducted, and then the dimming module is closed, so that the whole circuit does not work; when the PWM signal output is high, as no load exists, the protection module is directly connected to the ground through a lead, so that the voltage input into the control module is the same as the voltage of the protection module, the control module is not conducted at the moment, the dimming module is closed, and the whole circuit does not work, so that the dimming module is prevented from being impacted by high current, and the dimming module is protected.
The circuit can automatically recover to work after the short circuit fault is eliminated, the application is convenient, the improved circuit does not influence the normal PWM dimming function, and compared with the existing dimming circuit, the circuit has the advantages of fewer added devices, small cost influence and high practical value.
Further, the device also comprises a filtering module, wherein the filtering module is connected between the power supply and the ground.
By adopting the technical scheme, the filtering module is used for filtering the interference signals in the power supply, so that the output is more stable.
Further, the filtering module comprises a filtering capacitor, and the filtering capacitor is connected between a power supply and ground.
By adopting the technical scheme, the alternating current component in the input power supply is filtered by adopting the filter capacitor, so that the output voltage is stable and smooth direct current voltage, the cost is lower, and the use is convenient.
Further, the dimming module comprises a first MOS tube, a source electrode of the first MOS tube is connected with a power supply, a grid electrode of the first MOS tube is connected with a first output end of the biasing module, and a drain electrode of the first MOS tube is connected with an input anode of the LED light source.
Through adopting above-mentioned technical scheme, first MOS pipe is adjusted luminance to the LED light source, and when control module did not switch on, first MOS pipe was cut off, and LED light source load and power disconnection can't adjust luminance this moment. When the control module is conducted, the PWM signal controls the conduction time of the first MOS tube through the control module, and further controls the conduction time of the LED light source, so that dimming is realized.
Further, the first MOS tube is a P-channel MOS tube.
By adopting the technical scheme, the P-channel type MOS tube is conducted at a low level and matched with the control module, and when the control module is conducted, the grid input of the P-channel type MOS tube is at a low level and works normally.
Further, the control module comprises a second MOS tube, a third resistor and a fourth resistor, the drain electrode of the second MOS tube is connected with the second output end of the biasing module, the source electrode of the second MOS tube is grounded, the grid electrode of the second MOS tube is connected with one end of the third resistor, one end of the fourth resistor and the input end of the protection module, the other end of the third resistor receives PWM signals, and the other end of the fourth resistor is grounded.
Through adopting above-mentioned technical scheme, after the PWM signal passes through third resistor and fourth resistor partial pressure, input to the grid of second MOS pipe, when PWM signal input is high, the second MOS pipe switches on to control the conduction time of dimming module according to its conduction time, and then control the conduction time of LED light source, thereby realize dimming.
Further, the second MOS tube is an N-channel MOS tube.
By adopting the technical scheme, the N-channel MOS tube is conducted in a high level, and normally works when the input level of the PWM signal is high, and does not work when the input level of the PWM signal is low.
Further, the protection module comprises a diode, wherein the anode of the diode is connected with the first end of the control module, and the cathode of the diode is connected with the input anode of the LED light source.
Through adopting above-mentioned technical scheme, when LED light source load short circuit, PWM signal input is high, because no load, the negative pole ground connection of diode, the voltage of input second MOS pipe grid is unanimous with the voltage of diode, and the diode can restrict the input voltage of second MOS pipe grid for second MOS pipe is non-conductive, and then dimming module is also non-conductive, thereby protection dimming module avoids the impact of heavy current.
Further, the bias module comprises a first resistor and a second resistor, one end of the first resistor is connected with a power supply and the second end of the dimming module, the other end of the first resistor is connected with the first end of the dimming module and one end of the second resistor, and the other end of the second resistor is connected with the third end of the control module.
By adopting the technical scheme, when the control module is not conducted, the first resistor pulls up the voltage of the dimming module, and the dimming module is cut off; when the control module is conducted, the second resistor pulls down the voltage of the dimming module, and the dimming module is conducted, so that the switching effect of the dimming module is realized.
In a second aspect, the present application provides a lamp, which adopts the following technical scheme:
a lamp comprises an LED light source and the PWM dimming short-circuit protection circuit, wherein the LED light source is connected with the PWM dimming short-circuit protection circuit.
By adopting the technical scheme, the LED light source and the PWM dimming short-circuit protection circuit are combined, so that the lamp has a short-circuit protection function.
Drawings
Fig. 1 is a schematic diagram of a PWM dimming circuit in the background art.
Fig. 2 is a block diagram of a PWM dimming short-circuit protection circuit according to an embodiment of the present application.
Fig. 3 is a schematic diagram of a PWM dimming short-circuit protection circuit provided in an embodiment of the present application.
Reference numerals: 1. a dimming module; 2. a bias module; 3. a control module; 4. a protection module; 5. and a filtering module.
Detailed Description
The application discloses a PWM dimming short-circuit protection circuit and a lamp, which are used for making the purposes, the technical scheme and the effect of the application clearer and more definite, and the application is further described in detail below by referring to the accompanying drawings and the embodiment. It should be understood that the specific embodiments described herein are for purposes of illustration only and are not intended to limit the present application.
The embodiment of the application discloses a PWM dimming short-circuit protection circuit, as shown in fig. 2, the circuit includes: a dimming module 1, a control module 3, a protection module 4 and a biasing module 2. Wherein,
the dimming module 1 comprises three ends, a first end of the dimming module 1 is connected with the biasing module 2, a second end of the dimming module 1 is connected with a power supply, and a third end of the dimming module 1 is connected with an LED light source. The bias module 2 comprises an input end and two output ends, the input end of the bias module 2 is connected with a power supply, the first output end of the bias module 2 is connected with the first end of the dimming module 1, and the second output end of the bias module 2 is connected with the control module 3.
The control module 3 comprises three ends, a first end of the control module 3 receives the PWM signal, a second end of the control module 3 is grounded, a third end of the control module 3 is connected with a second output end of the bias module 2, and the control module 3 is used for controlling the dimming module 1 to dim the LED light source. The input of protection module 4 connects the first end of control module 3, and the third end and the LED light source of dimming module 1 are connected to the output of protection module 4, and protection module 4 can close control module when short circuit trouble, and then protects dimming module 1.
When the circuit works normally, the PWM signal output is low, the control module 3 is not conducted, the dimming module 1 is also closed, and the LED light source load does not work; when the PWM signal output is high, the control module 3 is conducted, the positive electrode and the negative electrode of the power supply are communicated through the bias module 2 and the control module 3, the dimming module 1 works normally, and at the moment, the control module 3 controls the dimming module 1 to dim the load of the LED light source. When the LED light source load has a short circuit fault, the PWM signal output is low, the control module 3 cannot be conducted, the dimming module 1 is closed, and the whole circuit does not work; the PWM signal output is high, and the protection module 4 is directly connected to the ground through a lead because of no load, so that the voltage input into the control module 3 is the same as the voltage of the protection module 4, the control module 3 is not conducted at the moment, the dimming module 1 is closed, and the whole circuit does not work, so that the dimming module 1 is prevented from being impacted by high current, and the dimming module 1 is protected.
In some embodiments, referring to fig. 2 and 3, the circuit further comprises a filter module 5, the filter module 5 being connected between the power supply and ground. Specifically, the filter module 5 is a filter capacitor C1.
The burr interference is filtered through the filter capacitor C1 to smooth the output waveform, so that the output voltage is more stable, the purpose of filtering is achieved, the cost is lower, and the use is convenient.
In some embodiments, referring to fig. 2 and 3, the dimming module 1 includes a first MOS transistor V1, a source of the first MOS transistor V1 is connected to a power supply, a gate of the first MOS transistor V1 is connected to a first output terminal of the bias module 2, and a drain of the first MOS transistor V1 is connected to an input positive electrode (led+). Specifically, the first MOS transistor V1 is a P-channel MOS transistor.
The first MOS tube V1 plays a role in dimming the LED light source. When the control module 3 is conducted, the bias module 2 is communicated, so that the first MOS tube V1 works normally, PWM signals control the conduction time of the first MOS tube V1 through the control module 3, and then control the conduction time of the LED light source, and dimming is achieved. When the control module 3 cannot be turned on, the first MOS tube V1 is also turned off, the whole circuit does not work, and dimming cannot be performed on the LED light source.
In some embodiments, referring to fig. 2 and 3, the bias module 2 includes a first resistor R1 and a second resistor R2, one end of the first resistor R1 is connected to the power supply and the second end of the dimming module 1, the other end of the first resistor R1 is connected to the first end of the dimming module 1 and one end of the second resistor R2, and the other end of the second resistor R2 is connected to the third end of the control module 3.
The first resistor R1 is a pull-up resistor, and the second resistor R2 is a pull-down resistor. When the control module 3 is not conducted, the first resistor R1 pulls up the grid voltage of the first MOS tube, the first MOS tube V1 is cut off, and the LED light source load does not lighten. When the control module 3 is turned on, the second resistor R2 pulls down the gate voltage of the first MOS tube V1, the first MOS tube V1 is turned on, and the LED light source load is communicated with a power supply, so that the LED light source can be lightened.
In some embodiments, referring to fig. 2 and 3, the control module 3 includes a second MOS transistor V2, a third resistor R3, and a fourth resistor R4, a drain of the second MOS transistor V2 is connected to an end of the second resistor R2 far from the first resistor R1, a source of the second MOS transistor V2 is grounded, a gate of the second MOS transistor V2 is connected to one end of the third resistor R3, one end of the fourth resistor R4, and an input end of the protection module 4, the other end of the third resistor R3 receives the PWM signal, and the other end of the fourth resistor R4 is grounded. The second MOS tube V2 is an N-channel MOS tube.
The third resistor R3 and the fourth resistor R4 are voltage dividing resistors. When the PWM signal input is high, the voltage is divided through the third resistor R3 and the fourth resistor R4, the voltage is input to the grid electrode of the second MOS tube V2, the second MOS tube V2 is conducted, the duty ratio of the second MOS tube V2 is adjusted, the conduction time of the first MOS tube V1 is controlled according to the conduction time of the second MOS tube V2, the conduction time of the LED light source load is controlled, and the dimming of the LED light source load is realized. When the PWM signal input is low, the second MOS tube V2 is cut off, then the first MOS tube is also closed, and the LED light source is not on.
In some embodiments, referring to fig. 2 and 3, the protection module 4 includes a diode D1, the anode of the diode D1 is connected to the gate of the second MOS transistor V2, one end of the third resistor R3, and one end of the fourth resistor R4, the cathode of the diode D1 is connected to the input anode (led+) of the LED light source, and the input cathode (LED-) of the LED light source is grounded.
When the LED light source load is in short circuit, PWM signals pass through the third resistor R3, the first path is grounded through the diode D1, the second path is grounded through the fourth resistor R4, the third path is input to the grid electrode of the second MOS tube V2, and as the voltage drop of the diode D1 is 0.7V, the voltage input to the grid electrode of the second MOS tube V1 is also 0.7V, the second MOS tube V2 is cut off, and then the first MOS tube V1 is also closed, so that the first MOS tube V1 is prevented from being damaged by impact heavy current generated by short circuit, and the protection effect on components is achieved. When the LED light source is in a normal working state, the cathode of the diode D1 is connected with the LED light source, at the moment, the diode D1 does not limit the input voltage of the grid electrode of the second MOS tube V2 any more, after the PWM signal is divided by the third resistor R3 and the fourth resistor R4, the second MOS tube V2 can be conducted, the first MOS tube V1 is conducted, and the circuit is recovered to normally adjust light.
The embodiment of the application also discloses a lamp, which comprises an LED light source and the PWM dimming short-circuit protection circuit, wherein the LED light source is connected with the PWM dimming short-circuit protection circuit, and the LED light source is used as a load of the PWM dimming short-circuit protection circuit.
The LED light source and the PWM dimming short-circuit protection circuit are combined, so that the lamp has a short-circuit protection function, the performance is more perfect, and the use experience is better.
Compared with the prior art, the application has the following advantages:
this application has set up protection module 4 through, when LED light source load short circuit, and input PWM signal, because protection module 4 passes through wire direct connection to ground, the voltage of input control module 3 is the same with protection module 4, and control module 3 does not switch on, and then dimming module 1 does not switch on yet, has consequently avoided dimming module 1 to receive the impact of heavy current, has protected it to avoid damaging. When the load is recovered to be normal, the input PWM signal is high, the control module 3 and the dimming module 1 are normally conducted again, and the circuit recovers to be normally dimming.
Therefore, the circuit has the short-circuit protection function, can automatically recover the work after the fault is eliminated, is convenient to apply, does not influence the normal PWM dimming function, and has fewer components, small cost influence and high practical value compared with the existing dimming circuit.
It is to be understood that the application of the present application is not limited to the examples described above, but may be modified or varied by a person skilled in the art from the description above, all of which are intended to be included within the scope of the utility model as defined in the accompanying claims.
Claims (10)
1. A PWM dimming short-circuit protection circuit, comprising: the device comprises a control module, a dimming module, a protection module and a bias module, wherein,
the second end of the dimming module is connected with a power supply, the first end of the dimming module is connected with the biasing module, and the third end of the dimming module is connected with an LED light source;
the bias module comprises an input end and two output ends, wherein the input end of the bias module is connected with a power supply, the first output end of the bias module is connected with the first end of the dimming module, and the second output end of the bias module is connected with the control module;
the first end of the control module receives a PWM signal, the second end of the control module is grounded, the third end of the control module is connected with the second output end of the bias module, and the control module is used for controlling the dimming module to dim the LED light source;
the input end of the protection module is connected with the first end of the control module, the output end of the protection module is connected with the third end of the dimming module and the LED light source, and the protection module is used for protecting the dimming module in case of short-circuit fault.
2. The PWM dimming short-circuit protection circuit of claim 1, further comprising a filter module connected between a power source and ground.
3. The PWM dimming short-circuit protection circuit according to claim 2, wherein the filter module comprises a filter capacitor connected between a power source and ground.
4. The PWM dimming short-circuit protection circuit according to claim 1, wherein the dimming module comprises a first MOS transistor, a source of the first MOS transistor is connected to a power supply, a gate of the first MOS transistor is connected to the first output terminal of the bias module, and a drain of the first MOS transistor is connected to an input anode of the LED light source.
5. The PWM dimming short-circuit protection circuit according to claim 4, wherein the first MOS transistor is a P-channel MOS transistor.
6. The PWM dimming short-circuit protection circuit according to claim 1, wherein the control module comprises a second MOS transistor, a third resistor and a fourth resistor, a drain electrode of the second MOS transistor is connected to the second output end of the bias module, a source electrode of the second MOS transistor is grounded, a gate electrode of the second MOS transistor is connected to one end of the third resistor, one end of the fourth resistor and an input end of the protection module, another end of the third resistor receives a PWM signal, and another end of the fourth resistor is grounded.
7. The PWM dimming short-circuit protection circuit according to claim 6, wherein the second MOS transistor is an N-channel MOS transistor.
8. The PWM dimming short-circuit protection circuit according to claim 1, wherein the protection module comprises a diode, the anode of the diode is connected to the first end of the control module, and the cathode of the diode is connected to the input anode of the LED light source.
9. The PWM dimming short-circuit protection circuit according to claim 1, wherein the bias module comprises a first resistor and a second resistor, one end of the first resistor is connected to a power supply and a second end of the dimming module, the other end of the first resistor is connected to the first end of the dimming module and one end of the second resistor, and the other end of the second resistor is connected to a third end of the control module.
10. A lamp comprising an LED light source and a PWM dimming short-circuit protection circuit according to any of claims 1-9, the LED light source and the PWM dimming short-circuit protection circuit being connected.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN202321910176.1U CN220273914U (en) | 2023-07-19 | 2023-07-19 | PWM dimming short-circuit protection circuit and lamp |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN202321910176.1U CN220273914U (en) | 2023-07-19 | 2023-07-19 | PWM dimming short-circuit protection circuit and lamp |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| CN220273914U true CN220273914U (en) | 2023-12-29 |
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Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CN202321910176.1U Active CN220273914U (en) | 2023-07-19 | 2023-07-19 | PWM dimming short-circuit protection circuit and lamp |
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| Country | Link |
|---|---|
| CN (1) | CN220273914U (en) |
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2023
- 2023-07-19 CN CN202321910176.1U patent/CN220273914U/en active Active
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