CN211429601U - Open circuit and short circuit detection circuit and LED switching power supply control system - Google Patents
Open circuit and short circuit detection circuit and LED switching power supply control system Download PDFInfo
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- CN211429601U CN211429601U CN202020498100.2U CN202020498100U CN211429601U CN 211429601 U CN211429601 U CN 211429601U CN 202020498100 U CN202020498100 U CN 202020498100U CN 211429601 U CN211429601 U CN 211429601U
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Abstract
The utility model provides an open circuit and short circuit detection circuit, which comprises a comparator U1, a voltage follower U2, a detection resistor R1 and a power switch device; a first end of the detection resistor R1 is used as an external voltage access end, a second end of the detection resistor R1 is respectively connected with a low-level end of the power switch device and a positive input end of the comparator U1, and a second end of the detection resistor R1 is synchronously used as a voltage feedback end; the control end of the power switch device is used as a switch signal receiving end to control the on-off of the power switch device; the negative input end of the comparator U1 is grounded, and the output end of the comparator U1 outputs a first voltage feedback signal through the current-limiting resistor R2; the input end of the voltage follower U2 is connected with the high-level end of the power switch device through a current-limiting resistor R3, the output end of the voltage follower U2 outputs a second voltage feedback signal through a current-limiting resistor R5, and the current-limiting resistor R3 is grounded through a voltage-dividing resistor R4. The application also comprises an LED switch power supply control system, and when the power supply circuit breaks down, the open circuit or the short circuit can be accurately detected.
Description
Technical Field
The utility model relates to an electronic circuit technical field especially relates to an open a way and short circuit detection circuitry to and use this detection circuitry's a LED switching power supply control system.
Background
At present, an LED driving power supply and a switching power supply are widely applied in the market, but most power supplies do not have independent open circuit and short circuit detection, but have detection but short circuit when the duty ratio of a Pulse Width Modulation (PWM) signal is small, at the moment, the short circuit cannot be detected, or the open circuit detection cannot be detected when the load is small, so that the system is falsely reported or the protection is not carried out after the fault occurs. Therefore, it is necessary to develop a new open circuit and short circuit detection circuit.
SUMMERY OF THE UTILITY MODEL
In order to solve the above problems, the present application provides an open circuit and short circuit detection circuit and an LED switching power supply control system using the open circuit and short circuit detection circuit, and the specific implementation manner is as follows:
an open circuit and short circuit detection circuit comprises a comparator U1, a voltage follower U2, a detection resistor R1 and a power switch device;
a first end of the detection resistor R1 is used as an external voltage access end, a second end of the detection resistor R1 is respectively connected with a low-level end of the power switch device and a positive input end of the comparator U1, and a second end of the detection resistor R1 is synchronously used as a voltage feedback end;
the control end of the power switch device is used as a switch signal receiving end to control the on-off of the power switch device;
the negative input end of the comparator U1 is grounded, and the output end of the comparator U1 outputs a first voltage feedback signal through the current-limiting resistor R2;
the input end of the voltage follower U2 is connected with the high-level end of the power switch device through a current-limiting resistor R3, the output end of the voltage follower U2 outputs a second voltage feedback signal through a current-limiting resistor R5, and the current-limiting resistor R3 is grounded through a voltage-dividing resistor R4;
the power supply end of the comparator U1 and the voltage follower U2 is connected with the first high level VCC, and the grounding end is connected with the ground.
In one or more embodiments of the present invention,
the power switch device is an MOS transistor Q1, the source electrode of the MOS transistor Q1 is connected with the second end of the detection resistor R1, the drain electrode is connected with the input end of the voltage follower U2 through the current-limiting resistor R3, and the grid electrode is used as a control end to receive a switch signal to control the on-off of the MOS transistor Q1.
In one or more embodiments of the present invention,
the positive input end of the comparator U1 is grounded through a filter capacitor C1, and the current limiting resistor R2 is grounded through a filter capacitor C2;
the input end of the voltage follower U2 is grounded through a filter capacitor C3, and the current limiting resistor R5 is grounded through a filter capacitor C4.
An LED switch power supply control system comprises a power supply circuit, a driving circuit, a signal processing circuit and a load, and also comprises any one of the open circuit and short circuit detection circuit;
the input end of the power circuit is connected with a live wire L and a zero wire N, the first output end of the power circuit is connected with a second high level VDD and then connected with the high level end of the load, the second output end of the power circuit is connected with a first high level VCC, the third output end of the power circuit is respectively connected with the ground and the first end of a detection resistor R1, and the high level end of the power switch device is connected with the low level end of the load;
the second end of the detection resistor R1 is connected with a driving circuit, and the driving circuit is connected with the control end of the power switch device;
the signal processing circuit is connected with the output end of the comparator U1 through a current limiting resistor R2, and is connected with the output end of the voltage follower U2 through a current limiting resistor R5.
In one or more embodiments of the present invention,
the power switch device is an MOS transistor Q1, the source electrode of the MOS transistor Q1 is connected with the second end of the detection resistor R1, the drain electrode is connected with the low level end of the load, and the grid electrode is connected with the driving circuit.
The utility model discloses the beneficial implementation effect who brings is: when the power circuit is open, no current exists in the detection resistor R1, so that no voltage exists in the detection resistor R1, and no voltage difference exists between two ends of the input end of the comparator U1, namely the first voltage feedback signal is 0; on the other hand, the control voltage input to the driving circuit by the detection resistor R1 is at a low level, the driving circuit controls the power switch device to be in a conducting state, the low level end of the load is at a low level, the voltage follower U2 detects the low level signal, the output end of the voltage follower U2 synchronously outputs the low level signal, and the signal processing circuit judges that the power circuit is in an open circuit state at the moment according to the voltage feedback signals of the comparator U1 and the voltage follower U2, so that corresponding protection action or signal feedback is carried out.
When the power circuit is short-circuited, the detection resistor R1 has a higher voltage, and a larger voltage difference is generated between the two ends of the input end of the comparator U1, that is, the first voltage feedback signal is 1; on the other hand, the control voltage input to the driving circuit by the detection resistor R1 is at a high level, the driving circuit controls the power switch device to turn off, the low-level end of the load is at a high level and is close to or equal to a second high level VDD, the voltage follower U2 detects the high-level signal, the output end of the voltage follower U2 synchronously outputs a high-level signal, at this time, because the power switch device is turned off, no voltage difference exists between two ends of the input end of the comparator U1, namely, the first voltage feedback signal is 0, and the signal processing circuit judges that the power circuit is in a short-circuit state at this time according to the change of the voltage feedback signal of the comparator U1 and the voltage value of the voltage feedback signal of the voltage follower U2.
Through the utility model discloses, after the circuit breaks down, can detect out open a way or short circuit more accurately through two sets of feedback signal, avoid misdetection, wrong report or malfunction, wait to get rid of the trouble back normal operating promptly, keep continuing normal use. The open circuit and short circuit detection circuit has simple structure and sensitive response, can be applied to various systems or circuits to be protected, such as the illumination field, the household appliance field and the like, and has higher popularization value; after the LED switch power supply control system applies the open circuit and short circuit detection circuit, the accuracy is greatly improved, the follow-up circuit or load can be timely and effectively protected, an LED semiconductor device sensitive to temperature, voltage or current can be effectively protected, and the service life of the system is prolonged.
Drawings
Fig. 1 is a working schematic diagram of an LED switching power supply control system disclosed in the present invention;
fig. 2 is a circuit diagram of a control system of a LED switching power supply disclosed in the present invention.
Detailed Description
In order to make the objects, technical solutions and advantages of the present invention more clearly understood, the present invention will be further described in detail with reference to the accompanying drawings 1-2 and the embodiments:
an open circuit and short circuit detection circuit 102 comprises a comparator U1, a voltage follower U2, a detection resistor R1 and a power switch device, wherein the comparator U1 and the voltage follower U2 form a core circuit of the detection circuit; a first end of the detection resistor R1 is used as an external voltage access end, a second end of the detection resistor R1 is respectively connected with a low-level end of the power switch device and a positive input end of the comparator U1, and a second end of the detection resistor R1 is synchronously used as a voltage feedback end; the control end of the power switch device is used as a switch signal receiving end to control the on-off of the power switch device; the negative input end of the comparator U1 is grounded, and the output end of the comparator U1 outputs a first voltage feedback signal through the current-limiting resistor R2; the input end of the voltage follower U2 is connected with the high-level end of the power switch device through a current-limiting resistor R3, the output end of the voltage follower U2 outputs a second voltage feedback signal through a current-limiting resistor R5, the current-limiting resistor R3 is grounded through a voltage-dividing resistor R4, the power supply end of the comparator U1 and the power supply end of the voltage follower U2 are connected with a first high-level VCC, and the ground end of the comparator U1 and the ground. Preferably, the power switch device is a MOS transistor Q1, the source of the MOS transistor Q1 is connected to the second end of the detection resistor R1, the drain is connected to the input end of the voltage follower U2 through a current limiting resistor R3, and the gate is used as a control end to receive a switch signal to control the on/off of the MOS transistor Q1. As a further improvement, the positive input end of the comparator U1 is grounded through a filter capacitor C1, and the current limiting resistor R2 is grounded through a filter capacitor C2; the input end of the voltage follower U2 is grounded through a filter capacitor C3, and the current limiting resistor R5 is grounded through a filter capacitor C4.
The application also provides an LED switch power supply control system, which comprises a power supply circuit 101, a driving circuit 103, a signal processing circuit 104 and a load 105, and also comprises the open circuit and short circuit detection circuit 102; the input end of the power circuit is connected with a live wire L and a zero wire N, the first output end of the power circuit 101 is connected with a high level end of the load 105 after being connected with a second high level VDD, the second output end of the power circuit is connected with a first high level VCC to serve as a power supply of a subsequent circuit, the third output end of the power circuit is respectively connected with the ground and the first end of a detection resistor R1, a voltage signal of the second end of the detection resistor R1 serves as an external voltage access signal of the open-circuit and short-circuit detection circuit 102, and the high level end of the power switch device serves as a connecting end and is connected with the low level end of the; a second end of the detection resistor R1 is connected with the driving circuit 103, and the driving circuit 103 is connected with a control end of the power switch device; the signal processing circuit 104 is connected with the output end of the comparator U1 through a current limiting resistor R2, and is connected with the output end of the voltage follower U2 through a current limiting resistor R5. Preferably, the power switch device is a MOS transistor Q1, the source of the MOS transistor Q1 is connected to the second end of the detection resistor R1, the drain is connected to the low-level end of the load 105, and the gate is connected to the driving circuit 103.
The use and function of the open and short detection circuit 102 is described by an LED switching power supply control system.
The working principle is explained as follows:
when the power circuit 101 is open, there is no current on the detection resistor R1, so there is no voltage on the detection resistor R1, and there is no voltage difference between the two ends of the input end of the comparator U1, i.e. the first voltage feedback signal is 0; on the other hand, the control voltage input to the drive circuit 103 from the detection resistor R1 is at a low level, the drive circuit 103 controls the MOS transistor Q1 to be in a conducting state, the low-level terminal of the load 105 is at a low level, the voltage follower U2 detects the low-level signal, the output terminal thereof synchronously outputs the low-level signal, and the signal processing circuit 104 determines that the power supply circuit 101 is in an open state at this time based on the voltage feedback signals of the comparator U1 and the voltage follower U2, thereby performing a corresponding protection operation or signal feedback.
When the power circuit 101 is short-circuited, the detection resistor R1 has a higher voltage, and a larger voltage difference is generated between the two ends of the input end of the comparator U1, that is, the first voltage feedback signal is 1; on the other hand, the control voltage input to the driving circuit 103 by the detection resistor R1 is at a high level, the driving circuit 103 controls the MOS transistor Q1 to turn off, the low level terminal of the load 105 is at a high level and close to or equal to the second high level VDD, the voltage follower U2 detects the high level signal, the output terminal synchronously outputs a high level signal, at this time, because the MOS transistor Q1 turns off, there is no voltage difference across the input terminals of the comparator U1, i.e., the first voltage feedback signal is 0, the signal processing circuit 104 determines that the power supply circuit is in a short-circuit state at this time according to the change of the voltage feedback signal of the comparator U1 and the voltage value of the voltage feedback signal of the voltage follower U2, so as to perform corresponding protection action or signal feedback, and it should be noted that the output voltage of the voltage follower U2 cannot be higher than the supply voltage thereof, i.
Table 1 shows voltage feedback signals received by the signal processing circuit 104 in different states of the LED switching power supply control system.
TABLE 1 Voltage feedback signals received by a Signal processing Circuit in different states
| Open circuit | Short circuit | Is normal | |
| First voltage feedback signal | 0 | 1→0 | 1 |
| Second voltage feedback signal | 0 | VDD and < VCC | 0 |
Under the normal working state, a certain current is loaded on the resistor R1, and the comparator U1 detects the voltage difference, namely the first voltage feedback signal is 1. Meanwhile, the driving circuit 103 controls the MOS transistor Q1 to be in a conducting state, and since the resistance of the resistor R1 is very small, the voltage applied to the resistor R3 is approximately equal to GND, the voltage value input to the voltage follower U2 is low, the output is also low, and the circuit can be judged to be in a normal working state at this time through two voltage feedback signals.
Through the utility model discloses, when power supply circuit 101 after breaking down, can detect out open a way or short circuit more accurately through two sets of voltage feedback signal, avoid misdetection, wrong report or malfunction, wait to go wrong after the trouble shooting normal operating promptly, keep continuing normal use. The open circuit and short circuit detection circuit 102 has a simple structure and sensitive response, can be applied to various systems or circuits to be protected, such as the illumination field, the household appliance field and the like, and has high popularization value; after the open circuit and short circuit detection circuit 102 is applied to the LED switch power supply control system, the accuracy is greatly improved, a subsequent circuit or a load can be timely and effectively protected, an LED semiconductor device sensitive to temperature, voltage or current can be effectively protected, and the service life of the system is prolonged.
For example, DALI dimming power supplies require systems that receive open and short circuit feedback from the output of the power circuit. The above-mentioned embodiments are merely the best embodiments of the present invention, and are not the only solutions, and are not limited to the above-mentioned embodiments, so long as the technical effects of the present invention are achieved by any of the same or similar means, all should fall within the protection scope of the present invention. The signal processing circuit 104 may be a microprocessor or other circuit, and the power switch device may be a MOS transistor Q1, an NPN transistor, or other devices.
In summary, for those skilled in the art, without departing from the principle of the present invention, several improvements can be made, and these improvements should be considered as within the protection scope of the present invention.
Claims (5)
1. An open and short detection circuit, characterized by: the circuit comprises a comparator U1, a voltage follower U2, a detection resistor R1 and a power switch device;
a first end of the detection resistor R1 is used as an external voltage access end, a second end of the detection resistor R1 is respectively connected with a low-level end of the power switch device and a positive input end of the comparator U1, and a second end of the detection resistor R1 is synchronously used as a voltage feedback end;
the control end of the power switch device is used as a switch signal receiving end to control the on-off of the power switch device;
the negative input end of the comparator U1 is grounded, and the output end of the comparator U1 outputs a first voltage feedback signal through the current-limiting resistor R2;
the input end of the voltage follower U2 is connected with the high-level end of the power switch device through a current-limiting resistor R3, the output end of the voltage follower U2 outputs a second voltage feedback signal through a current-limiting resistor R5, and the current-limiting resistor R3 is grounded through a voltage-dividing resistor R4;
the power supply end of the comparator U1 and the voltage follower U2 is connected with the first high level VCC, and the grounding end is connected with the ground.
2. The open and short detection circuit of claim 1, wherein:
the power switch device is an MOS transistor Q1, the source electrode of the MOS transistor Q1 is connected with the second end of the detection resistor R1, the drain electrode is connected with the input end of the voltage follower U2 through the current-limiting resistor R3, and the grid electrode is used as a control end to receive a switch signal to control the on-off of the MOS transistor Q1.
3. The open and short detection circuit according to claim 1 or 2, characterized in that:
the positive input end of the comparator U1 is grounded through a filter capacitor C1, and the current limiting resistor R2 is grounded through a filter capacitor C2;
the input end of the voltage follower U2 is grounded through a filter capacitor C3, and the current limiting resistor R5 is grounded through a filter capacitor C4.
4. The utility model provides a LED switching power supply control system, includes power supply circuit, drive circuit, signal processing circuit and load, its characterized in that: further comprising the open and short detection circuit of any of claims 1-3;
the input end of the power circuit is connected with a live wire L and a zero wire N, the first output end of the power circuit is connected with a second high level VDD and then connected with the high level end of the load, the second output end of the power circuit is connected with a first high level VCC, the third output end of the power circuit is respectively connected with the ground and the first end of a detection resistor R1, and the high level end of the power switch device is connected with the low level end of the load;
the second end of the detection resistor R1 is connected with a driving circuit, and the driving circuit is connected with the control end of the power switch device;
the signal processing circuit is connected with the output end of the comparator U1 through a current limiting resistor R2, and is connected with the output end of the voltage follower U2 through a current limiting resistor R5.
5. The LED switching power supply control system according to claim 4, wherein: the power switch device is an MOS transistor Q1, the source electrode of the MOS transistor Q1 is connected with the second end of the detection resistor R1, the drain electrode is connected with the low level end of the load, and the grid electrode is connected with the driving circuit.
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| Application Number | Priority Date | Filing Date | Title |
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| CN202020498100.2U CN211429601U (en) | 2020-04-07 | 2020-04-07 | Open circuit and short circuit detection circuit and LED switching power supply control system |
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| Application Number | Priority Date | Filing Date | Title |
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| CN202020498100.2U CN211429601U (en) | 2020-04-07 | 2020-04-07 | Open circuit and short circuit detection circuit and LED switching power supply control system |
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Cited By (5)
| Publication number | Priority date | Publication date | Assignee | Title |
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| CN112269149A (en) * | 2020-10-16 | 2021-01-26 | 深圳市沃特沃德股份有限公司 | Micro-current load open circuit detection circuit and terminal equipment |
| CN114488993A (en) * | 2021-12-20 | 2022-05-13 | 上海华兴数字科技有限公司 | Circuit state detection device and method |
| CN114585128A (en) * | 2020-12-02 | 2022-06-03 | 明纬(广州)电子有限公司 | Load open circuit detection circuit and LED driver with same |
| CN114609989A (en) * | 2021-11-25 | 2022-06-10 | 浙江中控技术股份有限公司 | High-power digital quantity output device and method for detecting and protecting open circuit and short circuit |
| CN116209119A (en) * | 2023-03-21 | 2023-06-02 | 珠海市圣昌电子有限公司 | DALI dimming power supply load detection circuit and method |
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2020
- 2020-04-07 CN CN202020498100.2U patent/CN211429601U/en active Active
Cited By (7)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN112269149A (en) * | 2020-10-16 | 2021-01-26 | 深圳市沃特沃德股份有限公司 | Micro-current load open circuit detection circuit and terminal equipment |
| CN114585128A (en) * | 2020-12-02 | 2022-06-03 | 明纬(广州)电子有限公司 | Load open circuit detection circuit and LED driver with same |
| CN114585128B (en) * | 2020-12-02 | 2024-01-12 | 明纬(广州)电子有限公司 | Open load detection circuit and LED driver with same |
| CN114609989A (en) * | 2021-11-25 | 2022-06-10 | 浙江中控技术股份有限公司 | High-power digital quantity output device and method for detecting and protecting open circuit and short circuit |
| CN114488993A (en) * | 2021-12-20 | 2022-05-13 | 上海华兴数字科技有限公司 | Circuit state detection device and method |
| CN116209119A (en) * | 2023-03-21 | 2023-06-02 | 珠海市圣昌电子有限公司 | DALI dimming power supply load detection circuit and method |
| CN116209119B (en) * | 2023-03-21 | 2023-08-25 | 珠海市圣昌电子有限公司 | DALI dimming power supply load detection circuit and method |
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