CN214544873U - LED overheating alarm circuit - Google Patents

Abstract

The utility model relates to a LED overheating alarm circuit, it includes rectifier module, the filter module, a control module, the step-down module, and the LED module, rectifier module output negative pole ground connection, the step-down module electricity is connected with alarm module, alarm module includes thermistor R1, alarm member U1, triode Q1 and definite value resistor R2, the anodal thermistor R1 and resistor R2 that loop through of step-down module output positive pole ground connection, or, the anodal thermistor R1 that loop through resistor R2 and resistor R1 that loop through of step-down module output positive pole, triode Q1 collecting electrode is connected the anodal output of step-down module electricity through alarm member U1, triode Q1 base and thermistor R1 are close to resistor R2 one end electricity and are connected, triode Q1 projecting pole ground connection; the resistance value of the thermistor R1 changes along with the temperature of the LED module, and when the voltage applied to the resistor R2 reaches a set value, the alarm device U1 works. This application has automatic alarm and reminds maintenance personal to maintain the operation effect.

Description

LED overheating alarm circuit

Technical Field

The application relates to the field of LED circuits, in particular to an LED overheating alarm circuit.

Background

The light emitting diode is called LED for short, is a common light emitting device, can efficiently convert electric energy into light energy by releasing energy through electron and hole recombination and emitting light, and is widely applied in the field of illumination.

At present, LED lamps for daily indoor and outdoor lighting are more and more popular, and are developed towards high power. However, the high-power LED generates a large amount of heat during operation, if the LED works at a high temperature for a long time, the service life of the LED is shortened, the lamp is not maintained in time, and the lamp is finally scrapped, but the maintenance personnel cannot accurately know when the LED lamp needs to be maintained.

In view of the above related technologies, the applicant believes that there is a defect that a maintenance person cannot be timely reminded of maintenance when an LED lamp is overheated.

SUMMERY OF THE UTILITY MODEL

In order to make automatic alarm remind maintenance personal to carry out maintenance operation when LED overtemperature, thereby reduce the LED and work condemned condition under high temperature for a long time, this application provides an LED overtemperature alarm circuit.

The application provides an overheated alarm circuit of LED adopts following technical scheme:

an LED overheating alarm circuit comprises a rectifying module, a filtering module electrically connected with the rectifying module, a control module electrically connected with the filtering module, a voltage reduction module electrically connected with the control module and an LED module electrically connected with the voltage reduction module, wherein the cathode of the output end of the rectifying module is grounded;

the voltage reduction module is electrically connected with an alarm module, the alarm module comprises a thermistor R1, an alarm part U1, a triode Q1 and a constant value resistor R2, the triode Q1 is an NPN type triode, the anode of the output end of the voltage reduction module is grounded through a thermistor R1 and a resistor R2 in sequence, or the anode of the output end of the voltage reduction module is grounded through a resistor R2 and a thermistor R1 in sequence, the anode of the input end of the alarm part U1 is electrically connected with the anode of the output end of the voltage reduction module, the cathode of the input end of the alarm part U1 is electrically connected with the collector of the triode Q1, the base of the triode Q1 is electrically connected with one end, close to the resistor R2, of the thermistor R1, and the emitter of the triode Q1 is grounded;

the resistance value of the thermistor R1 changes along with the temperature of the LED module, when the voltage applied to the base electrode of the triode Q1 is larger than the PN junction conducting voltage, the collector electrode and the emitter electrode of the triode Q1 are conducted, and the alarm piece U1 works.

Through adopting above-mentioned technical scheme, thermistor's resistance is along with the temperature variation of LED module, when the LED module did not reach the overheated state, the collecting electrode and the projecting pole of triode are not in the saturation conducting state, when the voltage of the out-of-work of alarm piece when exerting on triode Q1 base is greater than PN junction conducting voltage, the collecting electrode and the projecting pole of triode switch on, the alarm piece begins work and reminds maintainer to maintain to this reduces the condition that LED worked under high temperature for a long time, reduces the probability that LED damaged.

Preferably, the thermistor R1 is an NTC negative temperature coefficient thermistor, and the positive electrode of the output end of the voltage reduction module is grounded through a thermistor R1 and a resistor R2 in sequence.

By adopting the technical scheme, the NTC negative temperature coefficient thermistor has long service life, can still stably work for a long time after being examined by various high-precision, high-sensitivity, high-reliability, ultrahigh temperature and high pressure, and is favorable for ensuring the overheating alarm quality.

Preferably, the alarm part adopts a light emitting diode or/and a buzzer.

By adopting the technical scheme, maintenance personnel are reminded in a light signal or/and sound signal mode, and the probability that the maintenance personnel obtain maintenance signals is favorably improved.

Preferably, a first capacitor C4 is electrically connected between the base and the emitter of the triode Q1.

Through adopting above-mentioned technical scheme, first capacitor C4 is provided with and is favorable to reducing external interference to this condition emergence that reduces the detection module malfunction.

Preferably, the filtering module includes an inductor L1, a second capacitor C1 and a third capacitor C2, one end of the inductor L1 is electrically connected to the positive electrode of the output terminal of the rectifying module, the other end of the inductor L1 is electrically connected to the positive electrode of the input terminal of the control module, and two ends of the inductor L1 are grounded through the second capacitor C1 and the third capacitor C2, respectively.

By adopting the technical scheme, the inductor L1, the second capacitor C1 and the third capacitor C2 are adopted to form the duplex filter circuit, and a capacitor filter circuit or an inductor filter circuit is not adopted, so that the filter effect is improved, and the power supply quality of the circuit is ensured.

Preferably, the rectifier module comprises a rectifier bridge, and a current fuse F1 is connected in series with an input end of the rectifier bridge.

By adopting the technical scheme, when the circuit temperature is abnormal, the current fuse F1 can quickly cut off the circuit, thereby protecting the circuit.

Preferably, a piezoresistor RV1 is electrically connected between the two input ends of the rectifier bridge.

By adopting the technical scheme, when abnormal overvoltage occurs in the circuit, the voltage dependent resistor RV1 can be used for enabling the current flowing through the circuit to increase rapidly, so that the influence of the overvoltage on a subsequent circuit is reduced, the abnormal overvoltage is restrained, and the circuit is protected from being damaged by the overvoltage.

Preferably, the control module includes a KP107XL chip, an HVDD pin of the KP107XL chip is electrically connected to the positive electrode of the output terminal of the filtering module, an ROVP pin of the KP107XL chip is grounded through a first load, a GND pin of the KP107XL chip is directly grounded, both DRAIN pins of the KP107XL chip are electrically connected to the negative electrode of the input terminal of the voltage-reducing module, and a CS pin of the KP107XL chip is grounded through a second load.

By adopting the technical scheme, the KP107XL has quasi-resonance step-down constant current control, and the high-power MOSFET and the high-voltage starting/IC power supply circuit are integrated in one chip, so that the system design cost is greatly reduced. In addition, a high-precision current sensing control method is adopted, so that accurate output current and good line/load regulation are effectively kept, and functions and protections of current limiting, leading edge blanking, under-voltage locking, circulating current limiting, thermal backspacing, output overvoltage protection, LED open circuit/short circuit protection and the like are integrated.

In summary, the present application includes at least one of the following beneficial technical effects:

when the LED module works normally and does not reach an overheat state, a collector and an emitter of the diode are disconnected, and the alarm part is not electrified; when the LED works for a long time, the resistance value of the thermistor changes along with the temperature of the LED module, and when the voltage applied to the base electrode of the triode Q1 is greater than the PN junction conducting voltage, the collector electrode and the emitter electrode of the triode are conducted, and the alarm part starts to work, so that maintenance personnel are reminded to maintain, the condition that the LED works at high temperature for a long time is reduced, and the probability of damage to the LED is reduced;

KP107XL has quasi-resonance step-down constant current control, integrates high-power MOSFET and high-voltage start/IC power supply circuit in one chip, greatly reduces system design cost, and in addition, adopts high-precision current sensing control method, effectively keeps accurate output current and good line/load regulation, and integrates functions and protection of current limiting and leading edge blanking, under-voltage locking, circulation current limiting, thermal backspacing, output overvoltage protection, LED open circuit/short circuit protection, etc.

Drawings

Fig. 1 is a circuit diagram of an LED overheating alarm circuit in an embodiment of the present application.

Reference numerals: 1. a rectification module; 2. a filtering module; 3. a control module; 4. a voltage reduction module; 5. an LED module; 6. and an alarm module.

Detailed Description

The present application is described in further detail below with reference to fig. 1.

The embodiment of the application discloses an LED overheating alarm circuit.

Referring to fig. 1, the LED overheating alarm circuit includes a rectifying module 1, a filtering module 2, a control module 3, a voltage reduction module 4, an LED module 5, and an alarm module 6. The input end of the rectification module 1 is electrically connected with an alternating current power supply, the positive electrode of the output end of the rectification module 1 is electrically connected with the filtering module 2, and the negative electrode of the output end of the rectification module 1 is directly grounded. The output end of the filtering module 2 is electrically connected with the input end of the control module 3, the output end of the control module 3 is electrically connected with the input end of the voltage reduction module 4, and the output end of the voltage reduction module 4 is electrically connected with the input ends of the LED module 5 and the alarm module 6.

The rectifier module 1 comprises a rectifier bridge, a current fuse F1 and a piezoresistor RV1, wherein a first input end of the rectifier bridge is connected with a live wire of an alternating current power supply through the current fuse F1, a second input end of the rectifier bridge is connected with a zero wire of the alternating current power supply, the piezoresistor RV1 is electrically connected between the first input end and the second input end, and the negative pole of the output end of the rectifier bridge is directly grounded. When the circuit temperature is abnormal, the current fuse F1 can quickly cut off the circuit, so that the circuit is effectively protected; when the circuit generates abnormal overvoltage, the piezoresistor RV1 can effectively suppress the overvoltage, thereby protecting the circuit from the overvoltage.

The filtering module 2 comprises an inductor L1, a second capacitor C1 and a third capacitor C2, two ends of the inductor L1 are respectively and electrically connected with the positive electrode of the output end of the rectifier bridge and the positive electrode of the input end of the control module 3, and two ends of the inductor L1 are respectively grounded through the second capacitor C1 and the third capacitor C2. The inductor L1, the second capacitor C1 and the third capacitor C2 are matched with each other to form a duplex filter circuit, a filter circuit formed by a single capacitor or an inductor is not adopted, the filtering effect of the filter module 2 is improved, and the power supply quality of a subsequent circuit is ensured.

The control module 3 comprises a KP107XL chip, an HVDD end of the KP107XL chip is electrically connected with one end of the inductor L1 far away from the rectifier bridge, a DRAIN end of the KP107XL chip is electrically connected with the negative electrode of the input end of the voltage reduction module 4, an ROVP end and a CS end of the KP107XL chip are both grounded through a load, and a GND end is directly grounded. KP107XL has quasi-resonance step-down constant current control, integrates high-power MOSFET and high-voltage start/IC power supply circuit in one chip, greatly reduces system design cost. In addition, a high-precision current sensing control method is adopted, so that accurate output current and good line/load regulation are effectively kept, and functions and protections of current limiting, leading edge blanking, under-voltage locking, circulating current limiting, thermal backspacing, output overvoltage protection, LED open circuit/short circuit protection and the like are integrated.

The alarm module 6 includes an alarm U1, a transistor Q1, a thermistor R1, a first capacitor C4, and a resistor R2. The thermistor R1 has one end electrically connected to the positive electrode of the output terminal of the voltage step-down module 4 and the other end grounded through the resistor R2, the thermistor R1 is an NTC negative temperature coefficient thermistor and is located close to the LED module 5, and the temperature of the thermistor R1 varies with the temperature of the LED module 5. The positive electrode of the input end of the alarm U1 is electrically connected with the positive electrode of the output end of the voltage reduction module 4, the negative electrode of the input end of the alarm U1 is electrically connected with the collector electrode of the triode Q1, and the alarm U1 can adopt a light emitting diode or/and a buzzer. The base of the transistor Q1 is electrically connected to the thermistor R1 at the end away from the voltage-reducing module 4, the emitter of the transistor Q1 is grounded, and the first capacitor C4 is electrically connected between the base and the emitter of the transistor Q1.

Through the arrangement, when the LED circuit normally works, the collector and the emitter of the triode are disconnected, when the LED works at high temperature and the temperature reaches a certain value, the collector and the emitter are connected, the alarm starts to work, and therefore maintenance personnel are reminded to maintain. The NTC negative temperature coefficient thermistor has long service life, can stably work for a long time, is favorable for ensuring the overheating alarm quality and prolonging the service life of a circuit. The warning device U1 can alert maintenance personnel by means of light or/and sound signals, so that the maintenance personnel can respond to the LED in the high temperature state. The arrangement of the first capacitor C4 is beneficial to reducing external interference and reducing the occurrence of false operation of the detection module.

The implementation principle of the embodiment is as follows: the thermistor R1 is located close to the LED module 5, and the resistance value changes with the temperature of the LED module 5. When the LED module 5 works normally and does not reach an overheat state, the collector and the emitter of the triode Q1 are disconnected, and the alarm part does not work. After the LED module 5 works for a long time, the resistance value of the thermistor R1 is reduced along with the temperature rise of the LED module, when the voltage applied to the base electrode of the triode Q1 reaches a set value, the collector electrode and the emitter electrode of the triode Q1 are conducted, and the alarm piece U1 starts to work, so that maintenance personnel are reminded to maintain, the working time of the LED module 5 under the high-temperature condition is further reduced, and the probability of damage of the LED module 5 is reduced.

The above embodiments are preferred embodiments of the present application, and the protection scope of the present application is not limited by the above embodiments, so: all equivalent changes made according to the structure, shape and principle of the present application shall be covered by the protection scope of the present application.

Claims (8)

1. The utility model provides a LED alarm circuit that overheats, includes rectifier module (1), electricity connection filter module (2), the electricity of rectifier module (1) are connected control module (3), the electricity of filter module (2) are connected step-down module (4) and the electricity of control module (3) are connected LED module (5) of step-down module (4), the output negative pole ground connection of rectifier module (1), its characterized in that:

the voltage reduction module (4) is electrically connected with an alarm module (6), the alarm module (6) comprises a thermistor R1, an alarm U1, a triode Q1 and a fixed value resistor R2, the triode Q1 is an NPN type triode, the positive electrode of the output end of the voltage reduction module (4) is grounded through a thermistor R1 and a resistor R2 in sequence, or the positive electrode of the output end of the voltage reduction module (4) is grounded through a resistor R2 and a thermistor R1 in sequence; the positive electrode of the input end of the alarm device U1 is electrically connected with the positive electrode of the output end of the voltage reduction module (4), the negative electrode of the input end of the alarm device U1 is electrically connected with the collector electrode of the triode Q1, the base electrode of the triode Q1 is electrically connected with one end, close to the resistor R2, of the thermistor R1, and the emitter electrode of the triode Q1 is grounded;

the resistance value of the thermistor R1 changes with the temperature of the LED module (5), when the voltage applied on the resistor R2 reaches a set value, the collector and the emitter of the triode Q1 are conducted, and the alarm device U1 works.

2. The LED overheat warning circuit according to claim 1, wherein: the thermistor R1 is an NTC negative temperature coefficient thermistor.

3. The LED overheat warning circuit according to claim 2, wherein: the alarm part adopts a light emitting diode or/and a buzzer.

4. The LED overheat warning circuit according to claim 2, wherein: a first capacitor C4 is electrically connected between the base electrode and the emitter electrode of the triode Q1.

5. The LED overheat warning circuit according to claim 1, wherein: the filtering module (2) comprises an inductor L1, a second capacitor C1 and a third capacitor C2, one end of the inductor L1 is electrically connected with the positive electrode of the output end of the rectifying module (1), the other end of the inductor L1 is electrically connected with the positive electrode of the input end of the control module (3), and two ends of the inductor L1 are grounded through the second capacitor C1 and the third capacitor C2 respectively.

6. The LED overheat warning circuit according to claim 1, wherein: the rectifier module (1) comprises a rectifier bridge, and a current fuse F1 is connected in series with the input end of the rectifier bridge.

7. The LED overheat warning circuit according to claim 6, wherein: and a piezoresistor RV1 is electrically connected between the two input ends of the rectifier bridge.

8. The LED overheat warning circuit according to claim 1, wherein: the control module (3) comprises a KP107XL chip, an HVDD pin of the KP107XL chip is electrically connected with the positive electrode of the output end of the filtering module (2), an ROVP pin of the KP107XL chip is grounded through a first load, a GND pin of the KP107XL chip is directly grounded, two DRAIN pins of the KP107XL chip are both electrically connected with the negative electrode of the input end of the voltage reduction module (4), and a CS pin of the KP107XL chip is grounded through a second load.

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