LED driving circuit and LED lamp

Abstract

The present invention relates to the field of lighting technology, and provides an LED driving circuit and an LED lamp. The LED driving circuit includes: a rectifier module, a constant current driving module, a switch module and a temperature detection module; the rectifier module, the input end is connected to the mains, and the output end is connected to the positive pole of the LED light source; the constant current driving module, the input end is connected to the negative pole of the LED light source, the output end is grounded, and the current control end is connected to the first end of the switch module; the switch module, the second end is grounded, and the control end is connected to the output end of the temperature detection module; wherein the temperature detection module is used to detect the current temperature, and control the on-off of the switch module according to the current temperature obtained by the detection; the on-off of the switch module is used to adjust the driving current of the constant current driving module. The present invention detects the current temperature, and when the temperature reaches the preset temperature, the switch module is turned on, and the constant current driving module is controlled to reduce the current to achieve cooling, and the circuit structure is simple, easy to implement, and low cost.

Description

Technical Field

[0001] The present invention belongs to the technical field of lighting, and in particular relates to an LED driving circuit and an LED lamp. Background Art

[0002] LED (Light Emitting Diode) light sources have been widely used due to their advantages such as high efficiency, energy saving, environmental protection, long life and strong controllability. Since LED light sources generate heat during use, excessive temperature will affect the service life of LED light sources. Therefore, LED light sources need to be equipped with an over-temperature protection function, which automatically reduces the current to protect the LED light source when the temperature is too high.

[0003] In the prior art, LED light sources usually use over-temperature protection chips to adjust the output current to reduce power and thus reduce temperature, but the circuit structure is complex and the cost is high. Summary of the invention

[0004] In view of this, the embodiments of the present invention provide an LED driving circuit and an LED lamp to solve the problem in the prior art that the output current is adjusted by an over-temperature protection chip, resulting in a complex circuit structure and high cost.

[0005] A first aspect of an embodiment of the present invention provides an LED driving circuit, comprising: a rectifier module, a constant current driving module, a switch module and a temperature detection module;

[0006] Rectifier module, the input end is connected to the mains, and the output end is connected to the positive electrode of the LED light source;

[0007] A constant current driving module, wherein the input end is connected to the negative electrode of the LED light source, the output end is grounded, and the current control end is connected to the first end of the switch module;

[0008] The switch module has a second end connected to the ground and a control end connected to the output end of the temperature detection module;

[0009] The temperature detection module is used to detect the current temperature and control the on-off of the switch module according to the detected current temperature; the on-off of the switch module is used to adjust the driving current of the constant current driving module.

[0010] Optionally, the temperature detection module includes: a thermistor, a first voltage-stabilizing diode, a first resistor, a second resistor, a third resistor and a first capacitor;

[0011] A first voltage stabilizing diode, a cathode of which is respectively connected to the first end of the first resistor, the first end of the second resistor, the first end of the thermistor and the first end of the first capacitor, and an anode of which is grounded;

[0012] The second end of the thermistor and the first end of the third resistor are both connected to the output end of the temperature detection module;

[0013] The second end of the first resistor is connected to the first power supply end;

[0014] The second end of the second resistor, the second end of the first capacitor and the second end of the third resistor are all grounded.

[0015] Optionally, the temperature detection module further includes: a second voltage stabilizing diode;

[0016] The second voltage stabilizing diode has an anode connected to the output end of the temperature detection module, and a cathode connected to the second end of the thermistor and the first end of the third resistor respectively.

[0017] Optionally, the switch module includes: a first switch tube, a fourth resistor and a fifth resistor;

[0018] A first switch tube, a first end of which is connected to the first end of the switch module through a fourth resistor, a second end of which is connected to the second end of the switch module, and a control end of which is respectively connected to the control end of the switch module and the first end of the fifth resistor;

[0019] The second end of the fifth resistor is connected to the second end of the switch module.

[0020] Optionally, the rectifier module includes: a rectifier bridge and a unidirectional conductive element;

[0021] A rectifier bridge, the input end of which is connected to the mains, and the output end of which is connected to the anode of a unidirectional conductive element;

[0022] The cathode of the unidirectional conducting element is connected to the output end of the rectifying module.

[0023] Optionally, the constant current driving module includes: a constant current driving chip, a sixth resistor, a seventh resistor, an eighth resistor, a ninth resistor, a second capacitor and a third capacitor;

[0024] A constant current drive chip, wherein the enable end is connected to the first end of the seventh resistor, the power input end is respectively connected to the input end of the constant current drive module, the first end of the second capacitor and the first end of the eighth resistor, the ground end is grounded, the high voltage input end is connected to the first end of the ninth resistor, the current detection end is grounded through the sixth resistor, and the compensation end is respectively connected to the current control end of the constant current drive module and the first end of the third capacitor;

[0025] The second end of the seventh resistor is connected to the anode of the unidirectional conductive element, and the second end of the eighth resistor and the second end of the ninth resistor are both connected to the cathode of the unidirectional conductive element;

[0026] The second end of the second capacitor and the second end of the third capacitor are both grounded.

[0027] Optionally, the first power supply terminal is connected to the cathode of the unidirectional conducting element.

[0028] Optionally, the LED driving circuit further includes: a destroboscopic module;

[0029] The anti-strobe module has an input end connected to the output end of the rectifier module, and an output end connected to the positive electrode of the LED light source.

[0030] Optionally, the destroboscopic module includes: a second switch tube, a third voltage-stabilizing diode and a fourth capacitor;

[0031] The second switch tube has a first end respectively connected to the cathode of the third voltage-stabilizing diode and the input end of the destrobering module, a second end respectively connected to the output end of the destrobering module and the first end of the fourth capacitor, and a control end respectively connected to the anode of the third voltage-stabilizing diode and the second end of the fourth capacitor.

[0032] A second aspect of the embodiments of the present invention provides an LED lamp, comprising: an LED light source and any one of the LED driving circuits in the first aspect of the embodiments of the present invention;

[0033] The LED driving circuit is used to drive the LED light source to emit light.

[0034] The embodiment of the present invention provides an LED driving circuit, including: a rectifier module, a constant current driving module, a switch module and a temperature detection module; the rectifier module, the input end is connected to the mains, and the output end is connected to the positive pole of the LED light source; the constant current driving module, the input end is connected to the negative pole of the LED light source, the output end is grounded, and the current control end is connected to the first end of the switch module; the switch module, the second end is grounded, and the control end is connected to the output end of the temperature detection module; wherein the temperature detection module is used to detect the current temperature, and control the on-off of the switch module according to the current temperature detected; the on-off of the switch module is used to adjust the driving current of the constant current driving module. The present invention detects the current temperature, and when the temperature reaches the preset temperature, the switch module is turned on, and the driving current of the constant current driving module is pulled down to achieve cooling, and the circuit structure is simple, easy to implement, and low cost. BRIEF DESCRIPTION OF THE DRAWINGS

[0035] In order to more clearly illustrate the technical solutions in the embodiments of the present invention, the drawings required for use in the embodiments or the description of the prior art will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying creative labor.

[0036] Figure 1 1 is a schematic diagram of a circuit structure of an LED driving circuit provided by an embodiment of the present invention;

[0037] Figure 2 It is a circuit schematic diagram of an LED driving circuit provided by an embodiment of the present invention. DETAILED DESCRIPTION

[0038] In the following description, specific details such as specific system structures, technologies, etc. are provided for the purpose of illustration rather than limitation, so as to provide a thorough understanding of the embodiments of the present invention. However, it should be clear to those skilled in the art that the present invention may be implemented in other embodiments without these specific details. In other cases, detailed descriptions of well-known systems, devices, circuits, and methods are omitted to prevent unnecessary details from obstructing the description of the present invention.

[0039] In order to illustrate the technical solution of the present invention, specific embodiments are provided below for illustration.

[0040] refer to Figure 1 The present invention provides an LED driving circuit, including: a rectifier module 11, a constant current driving module 12, a switch module 13 and a temperature detection module 14;

[0041] The rectifier module 11 has an input end connected to the mains and an output end connected to the positive electrode of the LED light source 15;

[0042] The constant current driving module 12 has an input end connected to the negative electrode of the LED light source 15, an output end connected to the ground, and a current control end connected to the first end of the switch module 13;

[0043] The switch module 13 has a second end connected to the ground and a control end connected to the output end of the temperature detection module 14;

[0044] The temperature detection module 14 is used to detect the current temperature and control the on-off of the switch module 13 according to the detected current temperature; the on-off of the switch module 13 is used to adjust the driving current of the constant current driving module 12 .

[0045] In the embodiment of the present invention, the temperature detection module 14 is used to detect the current temperature (for example, the temperature detection module 14 can detect the temperature through the thermistor NTC), and the temperature detection module 14 sends a switch control signal to the switch module 13 according to the detected current temperature, and the switch control signal is used to control the on and off of the switch module 13, and the drive current of the constant current drive module 12 is adjusted by the on and off of the switch module 13. For example, when the current temperature reaches the preset temperature, the switch module 13 is turned on, the drive current of the constant current drive module 12 is lowered, the power is reduced, and the temperature is reduced. The LED drive circuit provided by the embodiment of the present invention has a simple structure, is easy to implement, and has low cost.

[0046] In some embodiments, reference Figure 2 , the temperature detection module 14 may include: a thermistor NTC, a first voltage stabilizing diode ZD1, a first resistor R1, a second resistor R2, a third resistor R3 and a first capacitor C1;

[0047] A first voltage zener diode ZD1, a cathode of which is respectively connected to a first end of the first resistor R1, a first end of the second resistor R2, a first end of the thermistor NTC and a first end of the first capacitor C1, and an anode of which is grounded;

[0048] The second end of the thermistor NTC and the first end of the third resistor R3 are both connected to the output end of the temperature detection module 14;

[0049] The second end of the first resistor R1 is connected to the first power supply end;

[0050] The second end of the second resistor R2 , the second end of the first capacitor C1 , and the second end of the third resistor R3 are all grounded.

[0051] In some embodiments, the thermistor NTC may be a negative temperature coefficient thermistor.

[0052] In some embodiments, the temperature detection module 14 may further include: a second voltage stabilizing diode ZD2;

[0053] The second voltage stabilizing diode ZD2 has an anode connected to the output end of the temperature detection module 14 , and a cathode connected to the second end of the thermistor NTC and the first end of the third resistor R3 .

[0054] In some embodiments, the switch module 13 may include: a first switch tube Q1, a fourth resistor R4 and a fifth resistor R5;

[0055] A first switch tube Q1, a first end of which is connected to the first end of the switch module 13 through a fourth resistor R4, a second end of which is connected to the second end of the switch module 13, and a control end of which is respectively connected to the control end of the switch module 13 and the first end of the fifth resistor R5;

[0056] A second end of the fifth resistor R5 is connected to a second end of the switch module 13 .

[0057] In some embodiments, the first switch tube Q1 may be an NPN transistor.

[0058] Since the voltage across the first voltage zener diode ZD1 remains unchanged, the voltage across the first end of the thermistor NTC remains unchanged. When the temperature rises, the resistance of the thermistor NTC decreases, the voltage across the second end of the thermistor NTC increases, and the voltage across the base of the first switch tube Q1 increases. When the temperature reaches the preset temperature, the voltage across the base of the first switch tube Q1 is high enough to turn on the first switch tube Q1, thereby lowering the drive current of the constant current drive module 12. In the embodiment of the present invention, the preset temperature value can be adjusted by adjusting the resistance of the third resistor R3 according to actual application requirements.

[0059] In some embodiments, the rectifier module 11 may include: a rectifier bridge BD1 and a unidirectional conductive element D1;

[0060] The input end of the rectifier bridge BD1 is connected to the mains, and the output end is connected to the anode of the unidirectional conductive element D1;

[0061] The cathode of the unidirectional conducting element D1 is connected to the output end of the rectifying module 11 .

[0062] In some embodiments, the rectifier module 11 may further include: a fuse element FR1 and a varistor RV1;

[0063] The fuse element FR1 is connected in series between the mains live wire and the rectifier bridge BD1;

[0064] The varistor RV1 has a first end connected to the output end of the rectifier bridge BD1 and a second end grounded.

[0065] In some embodiments, the rectifier module 11 may further include: a sixth capacitor C6;

[0066] The sixth capacitor C6 has a first end connected to the cathode of the unidirectional conducting element D1 and a second end grounded.

[0067] In some embodiments, the constant current driving module 12 may include: a constant current driving chip U1, a sixth resistor R6, a seventh resistor R7, an eighth resistor R8, a ninth resistor R9, a second capacitor C2 and a third capacitor C3;

[0068] The constant current driving chip U1, the enabling terminal (pin 3) is connected to the first end of the seventh resistor R7, the power input terminal (pin 4) is respectively connected to the input terminal of the constant current driving module 12, the first end of the second capacitor C2 and the first end of the eighth resistor R8, the grounding terminal is grounded, the high voltage input terminal (pin 5) is connected to the first end of the ninth resistor R9, the current detection terminal (pin 6) is grounded through the sixth resistor R6, and the compensation terminal (pin 8) is respectively connected to the current control terminal of the constant current driving module 12 and the first end of the third capacitor C3;

[0069] The second end of the seventh resistor R7 is connected to the anode of the unidirectional conductive element D1, and the second end of the eighth resistor R8 and the second end of the ninth resistor R9 are both connected to the cathode of the unidirectional conductive element D1;

[0070] A second end of the second capacitor C2 and a second end of the third capacitor C3 are both grounded.

[0071] In the embodiment of the present invention, the first end of the switch module 13 is connected to the compensation end (pin 8) of the constant current driver chip U1. When the temperature of the LED light source is too high, the resistance of the thermistor NTC decreases, the first switch tube Q1 is turned on, and current is pulled from the compensation end of the constant current driver chip U1, thereby reducing the drive current of the constant current driver chip U1, that is, the current of the LED light source 15 is reduced, and the temperature is reduced. Conversely, when the temperature decreases, the resistance of the thermistor NTC increases, the first switch tube Q1 is disconnected, and the current is stopped from being reduced, so that the temperature of the LED light source 15 is stabilized within a certain range.

[0072] In some embodiments, the first power terminal is connected to the cathode of the unidirectional conducting element D1 .

[0073] In some embodiments, the LED driving circuit may further include: a destroboscopic module 16;

[0074] The destroboscopic module 16 has an input end connected to the output end of the rectifier module 11 , and an output end connected to the positive electrode of the LED light source 15 .

[0075] In some embodiments, the destroboscopic module 16 may include: a second switch tube Q2, a third voltage stabilizing diode ZD3 and a fourth capacitor C4;

[0076] The second switch tube Q2 has a first end connected to the cathode of the third voltage stabilizing diode ZD3 and the input end of the destrobering module 16, a second end connected to the output end of the destrobering module 16 and the first end of the fourth capacitor C4, and a control end connected to the anode of the third voltage stabilizing diode ZD3 and the second end of the fourth capacitor C4.

[0077] In some embodiments, the second switch tube Q2 may be a NOMS tube.

[0078] The third voltage stabilizing diode ZD3 and the fourth capacitor C4 enable a constant voltage to be maintained between the gate and the drain of the second switch tube Q2, so that the second switch tube Q2 has a constant current characteristic, can filter out current ripples, and prevent flicker.

[0079] In some embodiments, the LED driving circuit may further include: a fifth capacitor C5;

[0080] The fifth capacitor C5 has a first end connected to the input end of the destroboscopic module 16 , and a second end connected to the cathode of the LED light source 15 .

[0081] In some embodiments, the fifth capacitor C5 may be a polarized capacitor;

[0082] The positive electrode of the fifth capacitor C5 is connected to the input end of the destroboscopic module 16 , and the negative electrode is connected to the negative electrode of the LED light source 15 .

[0083] The fifth capacitor C5 is used to filter out ripples.

[0084] Corresponding to any of the above-mentioned LED driving circuits, an embodiment of the present invention further provides an LED lamp, the LED lamp comprising: an LED light source and any of the above-mentioned LED driving circuits;

[0085] The LED driving circuit is used to drive the LED light source to emit light.

[0086] The above embodiments are only used to illustrate the technical solutions of the present invention, rather than to limit the same. Although the present invention has been described in detail with reference to the aforementioned embodiments, those skilled in the art should understand that the technical solutions described in the aforementioned embodiments may still be modified, or some of the technical features may be replaced by equivalents. Such modifications or replacements do not deviate the essence of the corresponding technical solutions from the spirit and scope of the technical solutions of the embodiments of the present invention, and should be included in the protection scope of the present invention.

Claims

1. An LED driving circuit, characterized in that: include: Rectification module, constant current drive module, switch module and temperature detection module; The rectifier module has an input end connected to the mains, and an output end connected to the positive electrode of the LED light source; The constant current driving module has an input end connected to the cathode of the LED light source, an output end connected to the ground, and a current control end connected to the first end of the switch module; The switch module has a second end connected to ground and a control end connected to the output end of the temperature detection module; The temperature detection module is used to detect the current temperature and control the on / off of the switch module according to the detected current temperature; the on / off of the switch module is used to adjust the driving current of the constant current driving module; The switch module includes: a first switch tube, a fourth resistor and a fifth resistor; The first switch tube has a first end connected to the first end of the switch module through the fourth resistor, a second end connected to the second end of the switch module, and a control end connected to the control end of the switch module and the first end of the fifth resistor respectively; The second end of the fifth resistor is connected to the second end of the switch module.

2. The LED driving circuit according to claim 1, characterized in that: The temperature detection module includes: a thermistor, a first voltage stabilizing diode, a first resistor, a second resistor, a third resistor and a first capacitor; The first voltage stabilizing diode has a cathode connected to the first end of the first resistor, the first end of the second resistor, the first end of the thermistor and the first end of the first capacitor, and an anode grounded; The second end of the thermistor and the first end of the third resistor are both connected to the output end of the temperature detection module; The second end of the first resistor is connected to the first power supply end; The second end of the second resistor, the second end of the first capacitor, and the second end of the third resistor are all grounded.

3. The LED driving circuit according to claim 2, characterized in that: The temperature detection module further includes: a second voltage stabilizing diode; The second voltage-stabilizing diode has an anode connected to the output end of the temperature detection module, and a cathode connected to the second end of the thermistor and the first end of the third resistor respectively.

4. The LED driving circuit according to claim 1, characterized in that: The rectifier module includes: a rectifier bridge and a unidirectional conductive element; The rectifier bridge has an input end connected to the mains power and an output end connected to the anode of the unidirectional conductive element; The cathode of the unidirectional conductive element is connected to the output end of the rectifying module.

5. The LED driving circuit according to claim 4, characterized in that: The constant current driving module comprises: a constant current driving chip, a sixth resistor, a seventh resistor, an eighth resistor, a ninth resistor, a second capacitor and a third capacitor; A constant current driving chip, wherein the enabling end is connected to the first end of the seventh resistor, the power input end is respectively connected to the input end of the constant current driving module, the first end of the second capacitor and the first end of the eighth resistor, the grounding end is grounded, the high voltage input end is connected to the first end of the ninth resistor, the current detection end is grounded through the sixth resistor, and the compensation end is respectively connected to the current control end of the constant current driving module and the first end of the third capacitor; The second end of the seventh resistor is connected to the anode of the unidirectional conductive element, and the second end of the eighth resistor and the second end of the ninth resistor are both connected to the cathode of the unidirectional conductive element; The second end of the second capacitor and the second end of the third capacitor are both grounded.

6. The LED driving circuit according to claim 4, characterized in that: The first power supply terminal is connected to the cathode of the unidirectional conducting element.

7. The LED driving circuit according to any one of claims 1 to 6, characterized in that: The LED driving circuit further includes: a destroboscopic module; The destroboscopic module has an input end connected to the output end of the rectifier module, and an output end connected to the positive electrode of the LED light source.

8. The LED driving circuit according to claim 7, characterized in that: The destroboscopic module includes: a second switch tube, a third voltage stabilizing diode and a fourth capacitor; The second switch tube has a first end respectively connected to the cathode of the third voltage-stabilizing diode and the input end of the de-strobe module, a second end respectively connected to the output end of the de-strobe module and the first end of the fourth capacitor, and a control end respectively connected to the anode of the third voltage-stabilizing diode and the second end of the fourth capacitor.

9. An LED lamp, characterized in that: include: An LED light source and an LED driving circuit as claimed in any one of claims 1 to 8; The LED driving circuit is used to drive the LED light source to emit light.

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