CN115802550A - High-reliability short-circuit protection circuit for PWM dimming - Google Patents
High-reliability short-circuit protection circuit for PWM dimming Download PDFInfo
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- CN115802550A CN115802550A CN202211569470.0A CN202211569470A CN115802550A CN 115802550 A CN115802550 A CN 115802550A CN 202211569470 A CN202211569470 A CN 202211569470A CN 115802550 A CN115802550 A CN 115802550A
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Abstract
The invention provides a high-reliability short-circuit protection circuit for PWM dimming, which comprises: the circuit comprises a dimming control circuit, a monostable trigger circuit, an MOS (metal oxide semiconductor) tube and a first resistor; the dimming control circuit is respectively connected with the monostable trigger circuit and the grid electrode of the MOS tube; the drain electrode of the MOS tube is connected with the cathode of the lamp; and the source electrode of the MOS tube is respectively connected with the monostable trigger circuit and one end of the first resistor. The short-circuit protection of the circuit provided by the invention has high reliability, and the short-circuit output can also play a role in protection under the state of dimming to low brightness.
Description
Technical Field
The invention relates to the technical field of short-circuit protection circuits, in particular to a high-reliability short-circuit protection circuit for PWM dimming.
Background
With the background of continuous temperature rise of smart homes, smart dimming is mainly used in smart homes, and more PWM dimming technologies are applied in smart dimming, but PWM dimming is prone to damage a dimming circuit under the condition of short-circuit output short circuit, and particularly, the short-circuit output is very prone to damage the dimming circuit under the dimming state.
The current short-circuit protection technology can only protect for a short time, if short-circuit output is carried out for a long time, the dimming circuit is still easy to damage, even the dimming circuit is heated seriously, and the risk of fire is caused; in a dimming state, especially when the brightness is adjusted to be below 50%, the protection effect cannot be achieved, and the dimming circuit is easy to damage.
Disclosure of Invention
To overcome the disadvantages of the prior art, it is an object of the present invention to provide a high reliability short-circuit protection circuit for PWM dimming.
In order to achieve the purpose, the invention provides the following scheme:
a high reliability short circuit protection circuit for PWM dimming, comprising:
the circuit comprises a dimming control circuit, a monostable trigger circuit, an MOS (metal oxide semiconductor) tube and a first resistor;
the dimming control circuit is respectively connected with the monostable trigger circuit and the grid electrode of the MOS tube; the drain electrode of the MOS tube is connected with the cathode of the lamp; and the source electrode of the MOS tube is respectively connected with the monostable trigger circuit and one end of the first resistor.
Preferably, the method further comprises the following steps: a positive output terminal and a negative output terminal;
the positive output terminals are respectively connected with the positive electrode of the lamp and the positive voltage of a power supply; the negative output terminal is arranged between the drain electrode of the MOS tube and the negative electrode of the lamp, and the drain electrode of the MOS tube is connected with the negative electrode of the lamp through the negative output terminal.
Preferably, the method further comprises the following steps: a second resistor, a third resistor and a transistor;
the second resistor is arranged on a connecting path of the grid electrode of the MOS tube and the dimming control circuit; one end of the second resistor is connected with the dimming control circuit, and the other end of the second resistor is respectively connected with the grid electrode of the MOS tube and the collector electrode of the transistor; the monostable trigger circuit is also connected with one end of the third resistor; the other end of the third resistor is connected with the base electrode of the transistor; and the emitter of the transistor is connected with the other end of the first resistor.
Preferably, the method further comprises the following steps: a drive circuit;
the driving circuit is arranged on a connection circuit of the grid electrode of the MOS tube and the second resistor; and the driving circuit is respectively connected with the other end of the second resistor and the grid electrode of the MOS tube.
Preferably, the other end of the first resistor is also connected to ground.
According to the specific embodiment provided by the invention, the invention discloses the following technical effects:
the invention provides a high-reliability short-circuit protection circuit for PWM dimming, which comprises: the circuit comprises a dimming control circuit, a monostable trigger circuit, an MOS (metal oxide semiconductor) tube and a first resistor; the dimming control circuit is respectively connected with the monostable trigger circuit and the grid electrode of the MOS tube; the drain electrode of the MOS tube is connected with the cathode of the lamp; and the source electrode of the MOS tube is respectively connected with the monostable trigger circuit and one end of the first resistor. The short-circuit protection of the circuit provided by the invention has high reliability, and the short-circuit output can also play a role in protection under the state of dimming to low brightness.
Drawings
In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the drawings needed to be used in the embodiments will be briefly described below, and it is obvious that the drawings in the following description are only some embodiments of the present invention, and it is obvious for those skilled in the art to obtain other drawings without inventive exercise.
Fig. 1 is a schematic diagram of a first circuit structure according to an embodiment of the present invention;
fig. 2 is a schematic diagram of a second circuit structure according to an embodiment of the present invention;
FIG. 3 is a schematic diagram of a third circuit structure according to an embodiment of the present invention;
fig. 4 is a schematic diagram of a third circuit structure according to an embodiment of the invention.
Description of the reference numerals:
the circuit comprises a 1-dimming control circuit, a 2-monostable trigger circuit, a 3-driving circuit, an R1-first resistor, an R2-second resistor, an R3-third resistor, a Q1-MOS (metal oxide semiconductor) tube, a Q2-transistor, a V + -positive output terminal, a V-negative output terminal and a U + -power supply positive voltage.
Detailed Description
The technical solutions in the embodiments of the present invention will be clearly and completely described below with reference to the drawings in the embodiments of the present invention, and it is obvious that the described embodiments are only a part of the embodiments of the present invention, and not all of the embodiments. All other embodiments, which can be derived by a person skilled in the art from the embodiments given herein without making any creative effort, shall fall within the protection scope of the present invention.
Reference herein to "an embodiment" means that a particular feature, structure, or characteristic described in connection with the embodiment can be included in at least one embodiment of the application. The appearances of the phrase in various places in the specification are not necessarily all referring to the same embodiment, nor are separate or alternative embodiments mutually exclusive of other embodiments. It is explicitly and implicitly understood by one skilled in the art that the embodiments described herein can be combined with other embodiments.
The terms "first," "second," "third," and "fourth," etc. in the description and claims of this application and in the accompanying drawings are used for distinguishing between different objects and not for describing a particular order. Furthermore, the terms "include" and "have," as well as any variations thereof, are intended to cover non-exclusive inclusions. For example, the inclusion of a list of steps, processes, methods, etc. is not limited to only those steps recited, but may alternatively include additional steps not recited, or may alternatively include additional steps inherent to such processes, methods, articles, or devices.
The invention aims to provide a high-reliability short-circuit protection circuit for PWM dimming, which has high short-circuit protection reliability and can protect short-circuit output in a dimming state to a low-brightness state.
In order to make the aforementioned objects, features and advantages of the present invention comprehensible, embodiments accompanied with figures are described in further detail below.
As shown in figure 1, the positive output terminal V + (the positive output terminal V + is connected with the positive voltage U + of the power supply) and the negative output terminal V-provide electric energy for the external LED lamp, the dimming control circuit 1 outputs a PWM dimming signal to the MOS tube Q1, and the brightness of the LED lamp is controlled by controlling the conduction duty ratio of the MOS tube. When the LED lamp is in short circuit, namely the output terminals V + and V-are in short circuit, if the MOS tube Q1 is in a conducting state, a large current flows through the MOS tube Q1 and the resistor R1. In this case, a relatively high voltage drop is generated at two ends of the first resistor R1, when the voltage drop reaches the trigger voltage threshold of the monostable trigger circuit 2, the monostable trigger circuit 2 outputs a pulse signal to the dimming control circuit 1, the dimming control circuit 1 stops outputting after receiving the pulse signal, and the MOS transistor Q1 is turned off accordingly. The process has high response speed, can close the MOS tube Q1 in a short time, realizes the short-circuit quick protection of the output terminal, and cannot damage the MOS tube Q1 and the dimming control circuit 1.
In the invention, the pulse signal output by the monostable trigger circuit 2 can adopt output positive pulse or output negative pulse to trigger the dimming control circuit 1 to close the output; the width of the pulse signal can be realized by adjusting the monostable flip-flop 2.
As shown in fig. 2, the improvement is made on the basis of fig. 1, a second resistor R2, a third resistor R3, and a transistor Q2 are added, so as to further improve the short-circuit protection performance, when the monostable flip-flop circuit 2 detects that the voltage across the first resistor R1 exceeds the trigger voltage threshold, the monostable flip-flop circuit 2 immediately outputs a pulse signal to the dimming control circuit 1 and the transistor Q2, the dimming control circuit 1 stops outputting after receiving the pulse signal, the MOS transistor Q1 is turned off, the dimming control circuit 1 receives the pulse signal, and a short time is provided from signal processing to signal stopping outputting, and the MOS transistor generates a large amount of heat due to the delay of the time; in order to turn off the MOS transistor in advance and reduce heat generated by loss, the pulse signal output by the monostable trigger circuit 2 is input to the dimming control circuit 1 and simultaneously triggers the transistor Q2 to be turned on through the third resistor R3, so that the MOS transistor Q1 is quickly turned off, and more reliable short-circuit protection performance is realized. The second resistor R2 string plays a role in limiting current between the dimming control circuit 1 and the MOS tube grid. In this embodiment, for example, the pulse signal triggered and output by the monostable trigger circuit 2 is at a high level, when a rising edge is input to the dimming control circuit 1, and the dimming control circuit 1 processes a signal, the transistor Q2 is already turned on to turn off the MOS transistor Q1, and when a falling edge of the pulse signal comes, the dimming control circuit 1 is already turned off to output, and at this time, the transistor Q2 is still in a conducting state, so that it is ensured that the MOS transistor Q1 is not turned on again to generate loss and generate heat. If the pulse signal output when the monostable trigger circuit 2 is triggered is a low level pulse, the transistor Q2 needs to select the P transistor.
As shown in fig. 3, when the driving capability of the dimming control circuit 1 is insufficient or the MOS transistor cannot be directly driven, a driving circuit 3 is added between the dimming control circuit 1 and the MOS transistor Q1 in addition to embodiment 2. When the transistor Q2 receives the pulse signal output by the monostable trigger circuit 2, the input end of the driving circuit 3 is turned off, and the output signal of the dimming control circuit 1 is turned off in advance, so that the MOS transistor Q1 is turned off quickly.
Fig. 4 is a specific embodiment of the embodiment of fig. 3, and fig. 4 is only for the purpose of illustrating the present invention and does not limit the scope of the present invention. The dimming control circuit 1 in fig. 4 may be implemented by a single chip microcomputer circuit or an analog circuit, and the input dimming signal may be 1 path or multiple paths, which does not limit the protection scope of the present invention; the monostable circuit 2 is not limited to being implemented as an amplifier; the driver circuit 3 is not limited to the low-side driver, and other driver circuits such as totem pole may be used.
In the present specification, the embodiments are described in a progressive manner, each embodiment focuses on differences from other embodiments, and the same and similar parts among the embodiments are referred to each other.
The principles and embodiments of the present invention have been described herein using specific examples, which are provided only to help understand the method and the core concept of the present invention; meanwhile, for a person skilled in the art, according to the idea of the present invention, the specific embodiments and the application range may be changed. In view of the foregoing, the description is not to be taken in a limiting sense.
Claims (5)
1. A high reliability short circuit protection circuit for PWM dimming, comprising:
the circuit comprises a dimming control circuit, a monostable trigger circuit, an MOS (metal oxide semiconductor) tube and a first resistor;
the dimming control circuit is respectively connected with the monostable trigger circuit and the grid electrode of the MOS tube; the drain electrode of the MOS tube is connected with the cathode of the lamp; and the source electrode of the MOS tube is respectively connected with the monostable trigger circuit and one end of the first resistor.
2. The high reliability short-circuit protection circuit for PWM dimming according to claim 1, further comprising: a positive output terminal and a negative output terminal;
the positive output terminal is respectively connected with the positive pole of the lamp and the positive voltage of the power supply; the negative output terminal is arranged between the drain electrode of the MOS tube and the negative electrode of the lamp, and the drain electrode of the MOS tube is connected with the negative electrode of the lamp through the negative output terminal.
3. The high reliability short-circuit protection circuit for PWM dimming according to claim 1, further comprising: a second resistor, a third resistor and a transistor;
the second resistor is arranged on a connecting path of the grid electrode of the MOS tube and the dimming control circuit; one end of the second resistor is connected with the dimming control circuit, and the other end of the second resistor is respectively connected with the grid electrode of the MOS tube and the collector electrode of the transistor; the monostable trigger circuit is also connected with one end of the third resistor; the other end of the third resistor is connected with the base electrode of the transistor; and the emitter of the transistor is connected with the other end of the first resistor.
4. The high reliability short-circuit protection circuit for PWM dimming according to claim 3, further comprising: a drive circuit;
the driving circuit is arranged on a connection circuit of the grid electrode of the MOS tube and the second resistor; and the driving circuit is respectively connected with the other end of the second resistor and the grid electrode of the MOS tube.
5. The high reliability short-circuit protection circuit for PWM dimming according to any of claims 1 to 4, wherein the other end of the first resistor is further connected to ground.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN202211569470.0A CN115802550A (en) | 2022-12-08 | 2022-12-08 | High-reliability short-circuit protection circuit for PWM dimming |
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| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN202211569470.0A CN115802550A (en) | 2022-12-08 | 2022-12-08 | High-reliability short-circuit protection circuit for PWM dimming |
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| CN115802550A true CN115802550A (en) | 2023-03-14 |
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| CN202211569470.0A Pending CN115802550A (en) | 2022-12-08 | 2022-12-08 | High-reliability short-circuit protection circuit for PWM dimming |
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Cited By (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN116528429A (en) * | 2023-05-18 | 2023-08-01 | 珠海市圣昌电子有限公司 | Rapid short-circuit protection method for LED dimming power supply |
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|---|---|---|---|---|
| CN202797872U (en) * | 2012-09-25 | 2013-03-13 | 天水七四九电子有限公司 | Novel short-circuit protection circuit |
| CN204333892U (en) * | 2014-08-10 | 2015-05-13 | 阚建峰 | A kind of intrinsically safe circuit improving capacitive load startup ability |
| DE102016004331A1 (en) * | 2016-04-13 | 2017-10-19 | J. Schneider Elektrotechnik Gmbh | Circuit arrangement for limiting a load current |
| CN107979073A (en) * | 2017-12-29 | 2018-05-01 | 中国电子科技集团公司第四十三研究所 | For the low-power consumption short-circuit protection circuit of DC/DC converters and guard method |
| CN112543538A (en) * | 2020-11-19 | 2021-03-23 | 惠州市西顿工业发展有限公司 | Constant voltage output dimming circuit of lamp source |
| CN114142841A (en) * | 2020-09-04 | 2022-03-04 | 英飞凌科技股份有限公司 | Driving and controlling circuit for electronic switch |
-
2022
- 2022-12-08 CN CN202211569470.0A patent/CN115802550A/en active Pending
Patent Citations (6)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN202797872U (en) * | 2012-09-25 | 2013-03-13 | 天水七四九电子有限公司 | Novel short-circuit protection circuit |
| CN204333892U (en) * | 2014-08-10 | 2015-05-13 | 阚建峰 | A kind of intrinsically safe circuit improving capacitive load startup ability |
| DE102016004331A1 (en) * | 2016-04-13 | 2017-10-19 | J. Schneider Elektrotechnik Gmbh | Circuit arrangement for limiting a load current |
| CN107979073A (en) * | 2017-12-29 | 2018-05-01 | 中国电子科技集团公司第四十三研究所 | For the low-power consumption short-circuit protection circuit of DC/DC converters and guard method |
| CN114142841A (en) * | 2020-09-04 | 2022-03-04 | 英飞凌科技股份有限公司 | Driving and controlling circuit for electronic switch |
| CN112543538A (en) * | 2020-11-19 | 2021-03-23 | 惠州市西顿工业发展有限公司 | Constant voltage output dimming circuit of lamp source |
Cited By (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN116528429A (en) * | 2023-05-18 | 2023-08-01 | 珠海市圣昌电子有限公司 | Rapid short-circuit protection method for LED dimming power supply |
| CN116528429B (en) * | 2023-05-18 | 2024-01-05 | 珠海市圣昌电子有限公司 | Rapid short-circuit protection method for LED dimming power supply |
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Application publication date: 20230314 |