NTC (Negative Temperature Coefficient) temperature derating circuit of operational amplifier comparator, LED (Light Emitting Diode) dimming method and lighting system

Abstract

The invention provides an NTC (Negative Temperature Coefficient) temperature derating circuit of an operational amplifier comparator, an LED (Light Emitting Diode) dimming method and a lighting system. The NTC temperature derating circuit comprises a first control circuit used for generating a reference voltage and a triangular wave signal; the second control circuit is used for generating a dynamic reference voltage according to the NTC resistance change; and the third control circuit generates a PWM signal by comparing the triangular wave with the dynamic reference voltage, and controls the LED current derating. A pure hardware circuit architecture based on an operational amplifier comparator is adopted, dependence on a software algorithm or an external controller is not needed, the complexity and cost of software development and debugging are remarkably reduced, and the method is particularly suitable for application scenes with high requirements for cost and reliability; temperature signals are collected in real time through the NTC resistor, and in combination with PWM dimming signals generated by the comparator, LED output current can be dynamically adjusted, and linear derating control is achieved. According to the scheme, performance degradation or damage caused by too high temperature of the LED can be effectively avoided, the service life of the LED is remarkably prolonged, and the system safety is remarkably improved.

Description

Technical Field

[0001] The present invention relates to the technical field of electronic circuit design and LED drive control, and in particular to an NTC temperature derating circuit for an operational amplifier comparator, an LED dimming method, and a lighting system. Background Art

[0002] With the widespread adoption of LED technology, the impact of operating temperature on lifespan and reliability has become increasingly prominent. LEDs are prone to overheating under high loads or high temperatures, leading to luminous efficacy degradation, color temperature drift, and even permanent damage. Therefore, dynamic current derating through temperature monitoring has become a core technology for protecting LEDs.

[0003] Currently, the industry generally uses solutions based on operational amplifier (op amp) control to achieve LED derating. For example, Chinese patent application number 202410168582.8 discloses a "circuit for stable current reduction" that uses an op amp to adjust the output current of the LED driver, thereby controlling derating. However, such solutions often rely on software algorithms or require complex control of the LED driver, which not only increases system development costs but also may have limitations in response speed and stability. Furthermore, solutions with high software reliance are prone to protection failures due to program delays or failures when faced with extreme temperature fluctuations.

[0004] On the other hand, some existing hardware solutions use discrete components to build control circuits. However, these designs are complex and lack dimming linearity, making accurate temperature-current mapping difficult. While these solutions can achieve basic derating, they suffer from redundant circuit structures, high costs, and limited dynamic response to NTC (negative temperature coefficient) thermistor (NTC) signals, resulting in poor matching of dimming effects with temperature changes.

[0005] In view of this, there is an urgent need for a pure hardware derating solution that does not rely on software, is low-cost and has a fast response. Summary of the Invention

[0006] In view of the defects in the prior art, the present invention aims to provide an NTC temperature derating circuit for an operational amplifier comparator, an LED dimming method and a lighting system.

[0007] An NTC temperature derating circuit for an operational amplifier comparator provided by the present invention includes:

[0008] A first control circuit includes a voltage-dividing resistor R1, a voltage-dividing resistor R2, a voltage-dividing resistor R3, a voltage-dividing resistor R4, a voltage-dividing resistor R5, a filter capacitor C1, a filter capacitor C2, and a first comparator, and is used to generate a reference voltage and a triangular wave signal; one end of the voltage-dividing resistor R1 and the voltage-dividing resistor R3 is connected to a power supply VCC, the other end of the voltage-dividing resistor R1 is connected to the voltage-dividing resistor R2, the voltage-dividing resistor R4, a non-inverting input end of the first comparator, and the filter capacitor C1; the other end of the voltage-dividing resistor R3 is connected to the other end of the voltage-dividing resistor R4, the voltage-dividing resistor R5, and the output end of the first comparator; the other end of the voltage-dividing resistor R2 and the other end of the filter capacitor C1 are grounded; the inverting input end of the first comparator is connected to the other end of the voltage-dividing resistor R5 and the filter capacitor C2; the other end of the filter capacitor C2 is grounded;

[0009] The second control circuit includes a voltage-dividing resistor R6, a voltage-dividing resistor R7, a voltage-dividing resistor R8, a voltage-dividing resistor R9, a voltage-dividing resistor R10, a filter capacitor C3, a filter capacitor C4, an NTC resistor, and a second comparator, and is used to generate a dynamic reference voltage according to the change of the NTC resistance; one end of the voltage-dividing resistor R6 and the voltage-dividing resistor R7 is connected to the power supply VCC; the other end of the voltage-dividing resistor R6 is connected to the voltage-dividing resistor R9 and the NTC resistor; the other end of the voltage-dividing resistor R7 is connected to the voltage-dividing resistor R8, the filter capacitor C3, and the non-inverting input of the second comparator; the other end of the voltage-dividing resistor R9 is connected to the voltage-dividing resistor R10, the filter capacitor C4, and the inverting input of the second comparator; the other end of the NTC resistor is grounded; the other end of the voltage-dividing resistor R8 and the filter capacitor C3 is grounded; the other end of the voltage-dividing resistor R10 and the filter capacitor C4 is grounded;

[0010] The third control circuit includes a third comparator, a resistor R11, and a switch control circuit. It generates a PWM signal by comparing the triangular wave with the dynamic reference voltage to control the LED current derating. The non-inverting input of the third comparator is connected to the inverting input of the first comparator. The inverting input of the third comparator is connected to the output of the second comparator. The output of the third comparator is connected to the resistor R11. The other end of the resistor R11 is connected to the power supply VCC.

[0011] Preferably, the non-inverting input terminal of the first comparator receives a reference voltage divided by resistors R1 and R2 and filtered by filter capacitor C1, the inverting input terminal is grounded through filter capacitor C2, and the output terminal is connected to resistor R5 to generate a triangular wave signal.

[0012] Preferably, in the second control circuit, the NTC resistor and the voltage divider resistors R6, R9 and R10 together form a temperature detection voltage divider network, whose output voltage is filtered by the filter capacitor C4 and then input into the inverting input terminal of the second comparator for dynamically adjusting the reference voltage.

[0013] Preferably, the non-inverting input terminal of the third comparator receives a triangular wave signal, and the inverting input terminal receives the dynamic reference voltage output by the second comparator. When the NTC temperature reaches the derating point, a low-level PWM signal is output, otherwise a high level signal is continuously output.

[0014] Preferably, the duty cycle of the PWM signal is linearly adjusted with the change of NTC temperature, and the LED constant voltage output is driven by the switch control circuit to achieve current derating without software intervention.

[0015] Preferably, the triangular wave signal is generated by alternating high and low levels output by the first comparator to charge and discharge the filter capacitor C2, and its frequency is determined by the resistance and capacitance parameters of the resistor R3, the resistor R4, the resistor R5 and the filter capacitor C2.

[0016] Preferably, the non-inverting input terminal of the second comparator receives a fixed reference voltage divided by resistors R7 and R8 and filtered by filter capacitor C3, the inverting input terminal receives a dynamic temperature detection voltage, and the output terminal is connected to the inverting input terminal of the third comparator to provide temperature feedback.

[0017] The present invention further provides an LED dimming method, which is implemented based on the NTC temperature derating circuit of the operational amplifier comparator described above, and comprises the following steps:

[0018] Step S1: Real-time temperature is collected through the NTC resistor and converted into a voltage signal;

[0019] Step S2: generating a triangular wave signal that is independent of temperature;

[0020] Step S3: Compare the temperature-related voltage with the triangle wave and output a PWM signal;

[0021] Step S4: adjusting the LED driving current according to the PWM duty cycle to achieve linear derating.

[0022] Preferably, when the NTC temperature does not reach the derating point, the duty cycle of the PWM signal remains at the maximum value; when the temperature exceeds the derating point, the duty cycle decreases linearly as the temperature increases.

[0023] The present invention also provides an LED lighting system, which includes the NTC temperature derating circuit of the operational amplifier comparator mentioned above, and the LED driver module. The PWM signal output by the circuit directly controls the switch tube of the driver module, thereby realizing temperature protection of the LED current in a pure hardware manner.

[0024] Compared with the prior art, the present invention has the following beneficial effects:

[0025] 1. This invention uses a pure hardware circuit architecture based on op amps and comparators, eliminating the need for software algorithms or external controllers. This significantly reduces the complexity and cost of software development and debugging, making it particularly suitable for applications with high cost and reliability requirements. By collecting temperature signals in real time through an NTC resistor and combining them with the PWM dimming signal generated by the comparator, the LED output current can be dynamically adjusted to achieve linear derating control. This solution effectively prevents LED performance degradation or damage caused by excessive temperature, significantly improving the LED's service life and system safety.

[0026] 2. The circuit of the present invention generates a stable reference voltage and triangular wave signal through the coordinated design of voltage-dividing resistors, filter capacitors, and multi-stage comparators, ensuring the accuracy and anti-interference capability of the PWM dimming signal. Compared with traditional software control solutions, the hardware circuit has a faster response speed and a more stable and reliable dimming process. The switching circuit drives the LED directly through the PWM signal, eliminating the need for external LED driver chips or complex control modules, reducing the overall system complexity and component costs, while also reducing potential failure points and improving maintenance convenience.

[0027] 3. The present invention achieves current derating through linear dimming, avoiding the current mutation or flickering problems caused by step dimming in traditional solutions, and further optimizing energy efficiency performance; it can be adapted to a variety of LED drive circuits and has wide compatibility and scalability. BRIEF DESCRIPTION OF THE DRAWINGS

[0028] Other features, objects and advantages of the present invention will become more apparent upon reading the detailed description of non-limiting embodiments with reference to the following drawings:

[0029] Figure 1 A circuit diagram of the present invention;

[0030] Figure 2 Schematic diagram of the voltage output by the second comparator of the present invention as the NTC resistance value changes;

[0031] Figure 3 Schematic diagram of a triangle wave at the non-inverting input terminal of the third comparator of the present invention;

[0032] Figure 4 Schematic diagram of PWM output by the third comparator of the present invention after voltage comparison;

[0033] Figure 5 Schematic diagram of LED current derating according to the present invention. DETAILED DESCRIPTION

[0034] The present invention will be described in detail below with reference to specific embodiments. The following examples will help those skilled in the art to further understand the present invention, but are not intended to limit the present invention in any form. It should be noted that, for those skilled in the art, several changes and improvements can be made without departing from the scope of the present invention. These all fall within the scope of protection of the present invention.

[0035] Example 1:

[0036] Reference Figure 1 and Figure 2 According to the present invention, an NTC temperature derating circuit for an operational amplifier comparator is provided, comprising:

[0037] A first control circuit includes a voltage-dividing resistor R1, a voltage-dividing resistor R2, a voltage-dividing resistor R3, a voltage-dividing resistor R4, a voltage-dividing resistor R5, a filter capacitor C1, a filter capacitor C2, and a first comparator, and is used to generate a reference voltage and a triangular wave signal; one end of the voltage-dividing resistor R1 and the voltage-dividing resistor R3 is connected to a power supply VCC, the other end of the voltage-dividing resistor R1 is connected to the voltage-dividing resistor R2, the voltage-dividing resistor R4, a non-inverting input end of the first comparator, and the filter capacitor C1; the other end of the voltage-dividing resistor R3 is connected to the other end of the voltage-dividing resistor R4, the voltage-dividing resistor R5, and the output end of the first comparator; the other end of the voltage-dividing resistor R2 and the other end of the filter capacitor C1 are grounded; the inverting input end of the first comparator is connected to the other end of the voltage-dividing resistor R5 and the filter capacitor C2; the other end of the filter capacitor C2 is grounded;

[0038] The second control circuit includes a voltage-dividing resistor R6, a voltage-dividing resistor R7, a voltage-dividing resistor R8, a voltage-dividing resistor R9, a voltage-dividing resistor R10, a filter capacitor C3, a filter capacitor C4, an NTC resistor, and a second comparator, and is used to generate a dynamic reference voltage according to the change of the NTC resistance; one end of the voltage-dividing resistor R6 and the voltage-dividing resistor R7 is connected to the power supply VCC; the other end of the voltage-dividing resistor R6 is connected to the voltage-dividing resistor R9 and the NTC resistor; the other end of the voltage-dividing resistor R7 is connected to the voltage-dividing resistor R8, the filter capacitor C3, and the non-inverting input of the second comparator; the other end of the voltage-dividing resistor R9 is connected to the voltage-dividing resistor R10, the filter capacitor C4, and the inverting input of the second comparator; the other end of the NTC resistor is grounded; the other end of the voltage-dividing resistor R8 and the filter capacitor C3 is grounded; the other end of the voltage-dividing resistor R10 and the filter capacitor C4 is grounded;

[0039] The third control circuit includes a third comparator, a resistor R11, and a switch control circuit. It generates a PWM signal by comparing the triangular wave with the dynamic reference voltage to control the LED current derating. The non-inverting input of the third comparator is connected to the inverting input of the first comparator. The inverting input of the third comparator is connected to the output of the second comparator. The output of the third comparator is connected to the resistor R11. The other end of the resistor R11 is connected to the power supply VCC.

[0040] The first comparator's non-inverting input receives a reference voltage divided by resistors R1 and R2 and filtered by filter capacitor C1. Its inverting input is grounded via filter capacitor C2, and its output is connected to resistor R5 to generate a triangular wave signal. In the second control circuit, an NTC resistor, along with voltage-dividing resistors R6, R9, and R10, form a temperature detection voltage-dividing network. Its output voltage is filtered by filter capacitor C4 and then input to the inverting input of the second comparator for dynamic adjustment of the reference voltage.

[0041] Reference Figure 3 and Figure 4 The non-inverting input of the third comparator receives the triangular wave signal, and the inverting input receives the dynamic reference voltage output by the second comparator. When the NTC temperature reaches the derating point, it outputs a low-level PWM signal, otherwise it continuously outputs a high level.

[0042] The PWM signal's duty cycle adjusts linearly with the NTC's temperature, driving the LED's constant voltage output through the switch control circuit, achieving current derating without software intervention. A triangular wave signal is generated by alternating high and low voltage levels output by the first comparator, charging and discharging filter capacitor C2. Its frequency is determined by the resistance and capacitance parameters of resistors R3, R4, R5, and filter capacitor C2.

[0043] The non-inverting input of the second comparator receives a fixed reference voltage divided by resistors R7 and R8 and filtered by filter capacitor C3, the inverting input receives a dynamic temperature detection voltage, and the output is connected to the inverting input of the third comparator to provide temperature feedback.

[0044] Reference Figure 5 The present invention also provides an LED dimming method, which is implemented based on the NTC temperature derating circuit of the operational amplifier comparator mentioned above, and comprises the following steps:

[0045] Step S1: Real-time temperature is collected through the NTC resistor and converted into a voltage signal;

[0046] Step S2: generating a triangular wave signal that is independent of temperature;

[0047] Step S3: Compare the temperature-related voltage with the triangle wave and output a PWM signal;

[0048] Step S4: adjusting the LED driving current according to the PWM duty cycle to achieve linear derating.

[0049] When the NTC temperature does not reach the derating point, the duty cycle of the PWM signal remains at the maximum value; when the temperature exceeds the derating point, the duty cycle decreases linearly as the temperature rises.

[0050] The present invention also provides an LED lighting system, which includes the NTC temperature derating circuit of the operational amplifier comparator mentioned above, and the LED driver module. The PWM signal output by the circuit directly controls the switch tube of the driver module, thereby realizing temperature protection of the LED current in a pure hardware manner.

[0051] Example 2:

[0052] A dimming circuit based on an op amp comparator can linearly dim the LED output current according to the NTC temperature change.

[0053] First control circuit: One end of voltage-divider resistor R1 is connected to an external power supply and one end of resistor R3. The other end of voltage-divider resistor R1 is connected to one end of filter capacitor C1, one end of voltage-divider resistor R2, one end of resistor R4, and the non-inverting input of the first comparator. The other end of filter capacitor C1 is grounded, as is the other end of voltage-divider resistor R2. The voltage is divided by resistors R1 and R2, filtered by capacitor C1, and then enters the non-inverting input of the first comparator as a reference voltage. The other end of resistor R3 is connected to the other end of resistor R4, one end of resistor R5, and the output of the first comparator. The other end of resistor R5 is connected to capacitor C2, the inverting input of the first comparator, and the non-inverting input of the third comparator. The other end of capacitor C2 is grounded.

[0054] Second control circuit: One end of voltage divider resistor R6 is connected to an external power supply and one end of resistor R7. The other end of voltage divider resistor R6 is connected to resistor R9 and one end of an NTC resistor that collects the temperature from the lamp panel. The other end of the NTC resistor is grounded. The other end of resistor R7 is connected to one end of resistor R8, one end of capacitor C3, and the non-inverting input of the second comparator. The other end of resistor R8 is grounded, and the other end of capacitor C3 is grounded. The other end of resistor R9 is connected to one end of resistor R10, one end of capacitor C4, and the inverting input of the comparator. The other end of resistor R10 is grounded, and the other end of capacitor C4 is grounded.

[0055] The third control circuit: the output end of the second comparator is connected to the inverting input end of the third comparator, one end of the resistor R11 is connected to the external power supply, and the other end is connected to the output of the third comparator and the switch control circuit.

[0056] By comparing the reference voltage at the non-inverting input of the first comparator with the voltage across capacitor C2, the first comparator alternates between high and low outputs, causing capacitor C2 to cycle between charging and discharging. This generates a triangular wave that is fed into the non-inverting input of the third comparator. Resistors R7 and R8 divide the voltage and filter it with capacitor C3 before feeding it into the non-inverting input of the second comparator, providing a reference voltage for the second comparator. The NTC resistance is collected, divided by resistors R6, R9, and R10, filtered by capacitor C4, and fed into the inverting input of the second comparator. Because the NTC resistance varies, the voltage at the inverting input of the second comparator changes with it. The non-inverting input of the third comparator receives a triangular wave, while the inverting input receives a voltage that varies with the NTC resistance. When the NTC temperature does not reach the set derating point, the voltage at the non-inverting input is greater than the voltage at the inverting input, and the third comparator outputs a continuous high level. When the NTC temperature reaches the derating point, the voltage at the inverting input is greater than the voltage at the non-inverting input, and the third comparator outputs a low level. Since the non-inverting input of the third comparator is a triangle wave, the output of the third comparator after comparison is PWM. The PWM signal is fed to the switching circuit to control the constant voltage output of the LED, thereby controlling the LED dimming and further reducing the LED current to protect the LED.

[0057] The present invention uses the input waveform of the comparator front end to make the comparator output a PWM dimming signal to the power output circuit to achieve LED current derating. By using a purely hardware-based LED derating circuit, the cost of software development is reduced.

[0058] Those skilled in the art may understand this embodiment as a more specific description of Embodiment 1.

[0059] Those skilled in the art will appreciate that, in addition to implementing the system and its various devices, modules, and units provided by the present invention in purely computer-readable program code, it is entirely possible to implement the same functions of the system and its various devices, modules, and units provided by the present invention in the form of logic gates, switches, application-specific integrated circuits, programmable logic controllers, and embedded microcontrollers by logically programming the method steps. Therefore, the system and its various devices, modules, and units provided by the present invention can be considered a hardware component, and the devices, modules, and units included therein for implementing various functions can also be considered as structures within the hardware component; the devices, modules, and units for implementing various functions can also be considered as both software modules implementing the method and structures within the hardware component.

[0060] The above describes specific embodiments of the present invention. It should be understood that the present invention is not limited to the specific embodiments described above, and those skilled in the art may make various changes or modifications within the scope of the claims, which do not affect the essence of the present invention. The embodiments of this application and the features in the embodiments may be combined with each other in any manner unless there is a conflict.

Claims

1. An NTC temperature derating circuit for an op amp comparator, characterized in that: include: A first control circuit includes a voltage-dividing resistor R1, a voltage-dividing resistor R2, a voltage-dividing resistor R3, a voltage-dividing resistor R4, a voltage-dividing resistor R5, a filter capacitor C1, a filter capacitor C2, and a first comparator, and is used to generate a reference voltage and a triangular wave signal; one end of the voltage-dividing resistor R1 and the voltage-dividing resistor R3 is connected to a power supply VCC, the other end of the voltage-dividing resistor R1 is connected to the voltage-dividing resistor R2, the voltage-dividing resistor R4, a non-inverting input end of the first comparator, and the filter capacitor C1; the other end of the voltage-dividing resistor R3 is connected to the other end of the voltage-dividing resistor R4, the voltage-dividing resistor R5, and the output end of the first comparator; the other end of the voltage-dividing resistor R2 and the other end of the filter capacitor C1 are grounded; the inverting input end of the first comparator is connected to the other end of the voltage-dividing resistor R5 and the filter capacitor C2; the other end of the filter capacitor C2 is grounded; The second control circuit includes a voltage-dividing resistor R6, a voltage-dividing resistor R7, a voltage-dividing resistor R8, a voltage-dividing resistor R9, a voltage-dividing resistor R10, a filter capacitor C3, a filter capacitor C4, an NTC resistor, and a second comparator, and is used to generate a dynamic reference voltage according to the change of the NTC resistance; one end of the voltage-dividing resistor R6 and the voltage-dividing resistor R7 is connected to the power supply VCC; the other end of the voltage-dividing resistor R6 is connected to the voltage-dividing resistor R9 and the NTC resistor; the other end of the voltage-dividing resistor R7 is connected to the voltage-dividing resistor R8, the filter capacitor C3, and the non-inverting input of the second comparator; the other end of the voltage-dividing resistor R9 is connected to the voltage-dividing resistor R10, the filter capacitor C4, and the inverting input of the second comparator; the other end of the NTC resistor is grounded; the other end of the voltage-dividing resistor R8 and the filter capacitor C3 is grounded; the other end of the voltage-dividing resistor R10 and the filter capacitor C4 is grounded; The third control circuit includes a third comparator, a resistor R11, and a switch control circuit. It generates a PWM signal by comparing the triangular wave with the dynamic reference voltage to control the LED current derating. The non-inverting input of the third comparator is connected to the inverting input of the first comparator. The inverting input of the third comparator is connected to the output of the second comparator. The output of the third comparator is connected to the resistor R11. The other end of the resistor R11 is connected to the power supply VCC.

2. The NTC temperature derating circuit of the operational amplifier comparator according to claim 1, characterized in that: The non-inverting input terminal of the first comparator receives the reference voltage divided by resistors R1 and R2 and filtered by filter capacitor C1, the inverting input terminal is grounded through filter capacitor C2, and the output terminal is connected to resistor R5 to generate a triangular wave signal.

3. The NTC temperature derating circuit of the operational amplifier comparator according to claim 1, characterized in that: In the second control circuit, the NTC resistor and the voltage divider resistors R6, R9 and R10 together form a temperature detection voltage divider network, whose output voltage is filtered by the filter capacitor C4 and then input into the inverting input terminal of the second comparator for dynamically adjusting the reference voltage.

4. The NTC temperature derating circuit for an operational amplifier comparator according to claim 1, wherein: The non-inverting input terminal of the third comparator receives a triangular wave signal, and the inverting input terminal receives a dynamic reference voltage output by the second comparator. When the NTC temperature reaches the derating point, a low-level PWM signal is output, otherwise a high-level signal is continuously output.

5. The NTC temperature derating circuit of the operational amplifier comparator according to claim 1, characterized in that: The duty cycle of the PWM signal is linearly adjusted with the change of NTC temperature, and the LED constant voltage output is driven by the switch control circuit to achieve current derating without software intervention.

6. The NTC temperature derating circuit of the operational amplifier comparator according to claim 1, characterized in that: The triangular wave signal is generated by alternating high and low levels output by the first comparator to charge and discharge the filter capacitor C2, and its frequency is determined by the resistance and capacitance parameters of the resistor R3, the resistor R4, the resistor R5 and the filter capacitor C2.

7. The NTC temperature derating circuit for an operational amplifier comparator according to claim 1, wherein: The non-inverting input terminal of the second comparator receives a fixed reference voltage divided by resistors R7 and R8 and filtered by filter capacitor C3, the inverting input terminal receives a dynamic temperature detection voltage, and the output terminal is connected to the inverting input terminal of the third comparator to provide temperature feedback.

8. A LED dimming method, characterized in that: The method is implemented based on the NTC temperature derating circuit of the operational amplifier comparator according to any one of claims 1 to 7, and the method comprises the following steps: Step S1: Real-time temperature is collected through the NTC resistor and converted into a voltage signal; Step S2: generating a triangular wave signal that is independent of temperature; Step S3: Compare the temperature-related voltage with the triangle wave and output a PWM signal; Step S4: adjusting the LED driving current according to the PWM duty cycle to achieve linear derating.

9. The LED dimming method according to claim 8, characterized in that: When the NTC temperature does not reach the derating point, the duty cycle of the PWM signal remains at the maximum value; when the temperature exceeds the derating point, the duty cycle decreases linearly as the temperature rises.

10. An LED lighting system, characterized in that: The system includes the NTC temperature derating circuit of the operational amplifier comparator according to any one of claims 1 to 7, and the system also includes an LED driver module. The PWM signal output by the circuit directly controls the switch tube of the driver module, thereby realizing temperature protection of the LED current in a pure hardware manner.

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