Digital analog temperature control dimming method, circuit, system and storage medium

Abstract

The invention relates to the technical field of illumination control, in particular to a digital analog temperature control dimming method, circuit and system and a storage medium. Comprising the following steps: acquiring an environment temperature signal in real time through a temperature sensing NTC resistor, and converting the temperature signal into a resistance value inversely proportional to the temperature; the NTC resistance value is converted into a voltage signal through a voltage dividing network, the voltage signal is transmitted to a reference voltage control point A, and the voltage of the point A changes along with changes of the NTC resistance value. The high-precision NTC resistor is used for collecting environment temperature signals, the environment temperature signals are converted into voltage signals through the voltage dividing network, the hysteresis comparator and the soft start / turn-off circuit are combined, the resolution ratio and stability of the temperature signals are effectively improved, and accurate control over LED brightness is ensured.

Description

Technical Field

[0001] The present invention relates to the field of lighting control technology, and in particular to a digital analog temperature control dimming method, circuit, system and storage medium. Background Art

[0002] Traditional LED dimming methods usually rely on manual adjustment or preset schedules and cannot be dynamically adjusted according to actual environmental conditions. Although some advanced dimming systems have introduced automatic dimming functions based on light sensors, these systems often ignore the impact of ambient temperature on LED performance. In fact, changes in ambient temperature can significantly affect the working state of LEDs, and thus affect their luminous efficiency and lifespan. In high temperature environments, the brightness of LEDs may decrease, while in low temperature environments, the brightness of LEDs may be too high, resulting in energy waste and poor results. Therefore, how to achieve efficient, accurate and adaptable digital analog temperature control dimming is a technical problem raised by the present invention. Summary of the invention

[0003] The present disclosure proposes a digital analog temperature control dimming method, circuit, system and storage medium, aiming to overcome at least one defect existing in the prior art.

[0004] To achieve the above purpose, the technical solution disclosed in the present invention is as follows:

[0005] According to one aspect of the present disclosure, a digital analog temperature control dimming method is provided, comprising the following steps:

[0006] The ambient temperature signal is collected in real time through the temperature sensing NTC resistor, and the temperature signal is converted into a resistance value inversely proportional to the temperature;

[0007] Convert the NTC resistance value into a voltage signal through a voltage divider network, and transmit the voltage signal to a reference voltage control point A, wherein the voltage at point A changes with the NTC resistance value;

[0008] When the voltage at point A rises to a preset threshold, the transistor Q1 is triggered to turn on, causing the IFB voltage to start rising;

[0009] As the IFB voltage increases, the feedback mechanism inside the LED driver chip reduces the VFB voltage, thereby reducing the LED current and achieving a reduction in brightness;

[0010] When the voltage at point A drops below a preset threshold, the transistor Q1 is triggered to turn off, the IFB voltage drops, the VFB voltage rises, and the LED current increases, thereby increasing the brightness.

[0011] Furthermore, the voltage divider network is composed of an NTC resistor, resistors R8 and R9, and the preset threshold is calculated as follows:

[0012] Wherein, Vth is a preset threshold, Vref is a reference voltage, and R8 and R9 represent the resistance values ​​of the resistors R8 and R9 respectively.

[0013] Furthermore, the relationship between the LED current and the VFB voltage is:

[0014] I LED =K*(V ref -VFB), where I LED is the LED current, K is the proportionality coefficient.

[0015] Furthermore, the steps of the simulated temperature control dimming method also include:

[0016] The proportional coefficient is dynamically adjusted through an adaptive algorithm to adapt to the dimming requirements under different ambient temperatures. The adjustment calculation formula of the proportional coefficient is:

[0017] K=K0·exp[-α·(TT ref ) 2 ], where K0 is the initial proportional coefficient, α is the adjustment factor, T is the current temperature, T ref is the reference temperature.

[0018] Furthermore, the analog temperature control dimming method also includes:

[0019] A linear amplifier is used to amplify the temperature signal to improve the resolution and stability of the signal;

[0020] A hysteresis comparator is set to prevent frequent switching of the state of Q1 near the critical voltage value;

[0021] By adjusting the change rate of the IFB voltage, smooth control of LED brightness changes can be achieved.

[0022] Furthermore, the analog temperature-controlled dimming method introduces a feedback loop for monitoring actual changes in LED current and fine-tuning the IFB voltage according to the actual changes to achieve more precise brightness control; the feedback loop includes a current sensor and a PID controller, and the output of the PID controller is used to adjust the IFB voltage.

[0023] According to another aspect of the present disclosure, a digital analog temperature control dimming circuit is provided, which is used to implement the digital analog temperature control dimming method as described above, and the analog temperature control dimming circuit includes:

[0024] The input power VIN and COM are rectified by a bridge rectifier composed of D1, D2, D3 and D4;

[0025] The rectified DC power passes through the EMC filter composed of L2 and C1, C2, and C3 to reduce electromagnetic interference and noise;

[0026] An LED driver chip, including VIN, DIM, BST, SW, and IFB pins;

[0027] The VIN pin is connected to the power input terminal to provide the operating voltage of the chip;

[0028] The DIM pin is used to receive the PWM dimming signal;

[0029] The BST pin uses a bootstrap circuit composed of R1 and C5 to improve the driving ability of the switch tube;

[0030] The SW pin is connected to one end of L1 to generate a switch signal to drive the LED;

[0031] The IFB pin is used to detect the LED current and adjust it;

[0032] In the LED output part, the SW pin passes through the LC filter composed of L1 and C7, and finally outputs to LED1 and LED2. RS1 and RS2 are used as current sampling resistors;

[0033] NTC thermistor, used to sense ambient temperature;

[0034] The NTC thermistor, R8 and R9 form a voltage divider network. When the voltage at point A reaches a certain threshold, transistor Q1 is turned on. The gate of transistor Q1 is connected to point A, the source is grounded, and the drain is connected to the IFB pin. When transistor Q1 is turned on, the IFB voltage increases, which in turn affects the VFB voltage, thereby adjusting the LED current.

[0035] Furthermore, the voltage at point A forms a reference voltage through R7 and D5;

[0036] When the voltage at point A reaches the preset threshold, Q1 is turned on, the IFB voltage increases, the VFB voltage decreases, the LED current decreases, and the brightness decreases;

[0037] When the voltage at point A drops below the preset threshold, Q1 turns off, the IFB voltage drops, the VFB voltage rises, the LED current increases, and the brightness increases;

[0038] RS1 and RS2 are used as current sampling resistors to monitor the actual changes of LED current;

[0039] The voltage across the current sampling resistor is fed back to the IFB pin of the LED driver chip to more accurately control the brightness.

[0040] According to another aspect of the present disclosure, a digital analog temperature control dimming system is provided, which is used to implement the digital analog temperature control dimming method as described above, and the analog temperature control dimming system includes:

[0041] Temperature signal acquisition module, used to collect ambient temperature signals through NTC resistors;

[0042] A signal conversion module, electrically connected to the temperature signal acquisition module, and used for converting the temperature signal into a voltage signal;

[0043] A voltage detection module, electrically connected to the signal conversion module, for detecting whether the voltage signal reaches a preset threshold;

[0044] a voltage control module, electrically connected to the voltage detection module, and configured to control the IFB voltage according to a change of the voltage signal;

[0045] The current control module is electrically connected to the voltage control module and is used to control the LED current according to the change of the IFB voltage.

[0046] According to another aspect of the present disclosure, a storage medium is provided, on which a computer program is stored. When the computer program is executed by a processor, the digital analog temperature control dimming method as described above is implemented.

[0047] The beneficial effects of the present invention are:

[0048] The present invention uses a high-precision NTC resistor to collect the ambient temperature signal, converts it into a voltage signal through a voltage divider network, and combines a hysteresis comparator and a soft start / shutdown circuit to effectively improve the resolution and stability of the temperature signal and ensure accurate control of the LED brightness. By introducing an adaptive algorithm to dynamically adjust the proportional coefficient K, the present invention can automatically adjust the LED current according to changes in the ambient temperature to ensure the stability and comfort of the LED brightness under different temperature conditions. This adaptive adjustment mechanism not only improves the response speed of the system, but also enhances the adaptability of the system.

[0049] The present invention monitors the ambient temperature in real time and automatically adjusts the LED brightness, thereby avoiding the problem of LED brightness reduction in a high temperature environment and excessive LED brightness in a low temperature environment, thereby achieving the effect of energy saving and extending the life of the LED. In addition, by optimizing the change rate of the IFB voltage and introducing a feedback loop, the energy efficiency of the system is further improved.

[0050] The above description is only an overview of the technical solution of the present invention. In order to more clearly understand the technical means of the present invention and implement it according to the contents of the specification, the following is a detailed description of the preferred embodiments of the present invention in conjunction with the accompanying drawings. BRIEF DESCRIPTION OF THE DRAWINGS

[0051] Figure 1 This is a flow chart of a digital analog temperature control dimming method according to an embodiment of the present invention;

[0052] Figure 2 This is a digital analog temperature control dimming circuit diagram in one embodiment of the present invention. DETAILED DESCRIPTION

[0053] The following will be combined with the drawings in the embodiments of the present invention to clearly and completely describe the technical solutions in the embodiments of the present invention. Obviously, the described embodiments are part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0054] The term "comprise" and any variation thereof in the specification and claims of the present application are intended to cover non-exclusive inclusions, for example, a process, method, system, product or device comprising a series of steps or units need not be limited to those steps or units clearly listed, but may include other steps or units that are not clearly listed or inherent to these processes, methods, products or devices. In addition, the use of "and / or" in the specification and claims to indicate at least one of the connected objects, such as A and / or B, means including A alone, B alone, and A and B.

[0055] In the embodiments of the present invention, words such as "exemplary" or "for example" are used to indicate examples, illustrations or explanations. Any embodiment or design described as "exemplary" or "for example" in the embodiments of the present invention should not be interpreted as being more preferred or more advantageous than other embodiments or designs. Specifically, the use of words such as "exemplary" or "for example" is intended to present related concepts in a specific way.

[0056] The present invention provides the following preferred embodiments:

[0057] Embodiment 1

[0058] In order to solve the problem that the existing LED dimming method cannot dynamically adjust the brightness according to the ambient temperature change, this embodiment proposes a digital analog temperature control dimming method. Figure 1 As shown, the steps of the digital analog temperature control dimming method include:

[0059] S100, collects ambient temperature signals in real time through a temperature sensing NTC resistor, and converts the temperature signals into resistance values ​​inversely proportional to the temperature.

[0060] S200, converting the NTC resistance value into a voltage signal through a voltage divider network, and transmitting the voltage signal to a reference voltage control point A, wherein the voltage at point A changes with the NTC resistance value.

[0061] S300 , when the voltage at point A rises to a preset threshold, transistor Q1 is triggered to turn on, so that the voltage at IFB starts to rise.

[0062] S400, as the IFB voltage increases, the feedback mechanism inside the LED driver chip reduces the VFB voltage, thereby reducing the LED current and achieving a reduction in brightness.

[0063] S500, when the voltage at point A drops below a preset threshold, the transistor Q1 is triggered to turn off, the IFB voltage drops, the VFB voltage rises, and the LED current increases, thereby increasing the brightness.

[0064] Furthermore, the NTC resistor is a negative temperature coefficient thermistor whose resistance decreases as the temperature increases. In this embodiment, a high-precision NTC resistor of model NTC10K-470 is selected to ensure accurate acquisition of the temperature signal. This NTC resistor has good linearity and stability and can provide reliable temperature measurement in a wide temperature range.

[0065] Furthermore, the NTC resistance value is converted into a voltage signal through a voltage divider network, and the voltage signal is transmitted to the reference voltage control point A. The voltage divider network is composed of an NTC resistor, resistors R8 and R9. Specifically, one end of the NTC resistor is connected to the power supply Vcc, the other end is connected to one end of R8, the other end of R8 is connected to one end of R9, and the other end of R9 is grounded. Point A is located between the NTC resistor and R9, and its voltage changes with the change of the NTC resistor. It should be understood that the design of the voltage divider network enables the voltage at point A to accurately reflect the change of ambient temperature.

[0066] Furthermore, when the voltage at point A rises to a preset threshold, transistor Q1 is triggered to turn on. Transistor Q1 uses an N-channel MOSFET, with its gate connected to point A, its drain grounded through resistor R8, and its source connected to the IFB pin. When the voltage at point A reaches a preset threshold, Q1 turns on and the IFB voltage starts to rise. It can be understood that transistor Q1, as a switching element, has a conduction state that directly affects the change of the IFB voltage.

[0067] Furthermore, as the IFB voltage rises, the feedback mechanism inside the LED driver chip reduces the VFB voltage, thereby reducing the LED current and achieving a reduction in brightness. Specifically, the LED driver chip adjusts the output current by detecting the voltage of the IFB pin. When the IFB voltage rises, the feedback mechanism inside the driver chip reduces the VFB voltage, thereby reducing the LED current and causing the LED brightness to decrease. Conversely, when the voltage at point A drops below the preset threshold, the transistor Q1 is triggered to turn off, the IFB voltage drops, the VFB voltage rises, and the LED current increases, achieving an increase in brightness.

[0068] Furthermore, in order to improve the stability and response speed of the system, a hysteresis comparator is also introduced in this embodiment. The hysteresis comparator is used to prevent the state of Q1 from being frequently switched near the critical voltage value, thereby avoiding oscillation in the system. The specific design of the hysteresis comparator includes two different thresholds: one for triggering Q1 to turn on, and the other for triggering Q1 to turn off. This ensures that the state switching of Q1 is smoother when the temperature changes.

[0069] Furthermore, in order to ensure the resolution and stability of the temperature signal, the present embodiment also uses a linear amplifier to amplify the temperature signal. The linear amplifier can effectively improve the signal-to-noise ratio of the temperature signal, thereby improving the accuracy and reliability of the entire system. The specific model of the linear amplifier can be selected according to actual needs, such as a high-performance operational amplifier such as LM358 or OP07.

[0070] The benefit of this embodiment is that by using high-precision NTC resistors and voltage divider networks, combined with hysteresis comparators and linear amplifiers, high-precision acquisition and conversion of ambient temperature is achieved. At the same time, through the coordinated work of transistor Q1 and LED driver chip, dynamic adjustment of LED brightness is achieved. This method not only improves the response speed and stability of the system, but also ensures the stability and comfort of LED brightness under different temperature conditions. By real-time monitoring of ambient temperature and automatically adjusting LED brightness, the problem of LED brightness reduction in high temperature environment and excessive LED brightness in low temperature environment is avoided, thereby achieving energy saving and extending LED life.

[0071] Embodiment 2

[0072] In order to solve the problem of calculating the preset threshold value in the voltage divider network, this embodiment further optimizes the specific design of the voltage divider network. Specifically, the voltage divider network is composed of an NTC resistor, resistors R8 and R9, and the preset threshold value is calculated as follows:

[0073] Among them, V th is the preset threshold, V ref is the reference voltage, and R8 and R9 represent the resistance values ​​of resistors R8 and R9 respectively.

[0074] Furthermore, high-precision resistors R8 and R9 are selected to ensure the stability and accuracy of the voltage divider network. In this embodiment, R8 uses a 10kΩ precision resistor and R9 uses a 5kΩ precision resistor. These resistors have low temperature coefficients and high stability, and can maintain constant resistance over a wide temperature range. It should be understood that by accurately selecting the resistance values ​​of R8 and R9, accurate control of the preset threshold can be achieved.

[0075] Furthermore, the reference voltage V ref It is usually provided by a stable reference voltage source, such as LM4040-2.5V. This reference voltage source can provide a high-precision and stable reference voltage, thereby ensuring that the calculation result of the preset threshold is accurate and reliable. It can be understood that the choice of reference voltage affects the performance of the entire system, so a high-precision and stable reference voltage source should be selected.

[0076] Furthermore, in order to further improve the stability of the system, a filter capacitor can be added to the voltage divider network. For example, a small-capacity ceramic capacitor (such as 10nF) is connected in parallel at point A to filter out high-frequency noise and improve signal stability. In addition, a small resistor (such as 100Ω) can be connected in series between the NTC resistor and R8 to limit the current and protect the NTC resistor from overcurrent damage.

[0077] Furthermore, through the above design, the voltage divider network can accurately convert the change of the NTC resistance into a voltage signal, and determine the on and off conditions of the transistor Q1 through the calculation formula of the preset threshold value. This ensures that under different temperature conditions, the system can accurately respond to changes in ambient temperature and realize dynamic adjustment of LED brightness.

[0078] The benefit of this embodiment is that accurate calculation and control of the preset threshold value is achieved by accurately designing the voltage divider network and selecting appropriate resistors and reference voltage sources. This not only improves the stability and reliability of the system, but also ensures accurate adjustment of the LED brightness under different temperature conditions, thereby achieving energy saving and extending the life of the LED.

[0079] Embodiment 3

[0080] In order to solve the problem of the relationship between the LED current and the VFB voltage, this embodiment further refines the calculation method of the LED current. Specifically, the relationship between the LED current and the VFB voltage is:

[0081] I LED =K*(V ref -VFB), where I LED is the LED current, K is the proportional coefficient, and VFB is the feedback voltage.

[0082] Furthermore, the proportionality coefficient K is a key parameter that determines the sensitivity of the LED current to the change of the VFB voltage. In this embodiment, the selection of the proportionality coefficient K should be adjusted according to the actual application requirements. Usually, a fixed initial value can be selected, such as K = 0.1A / V. This initial value can be determined by experiment or simulation to ensure that the LED current changes within a reasonable range.

[0083] Furthermore, the feedback voltage VFB is generated by the feedback mechanism inside the LED driver chip. When the IFB voltage rises, the VFB voltage decreases, thereby reducing the LED current; conversely, when the IFB voltage decreases, the VFB voltage increases, thereby increasing the LED current. This feedback mechanism can achieve precise control of the LED current, thereby achieving dynamic adjustment of the brightness.

[0084] Furthermore, through the above design, the relationship between the LED current and the VFB voltage can be precisely controlled, thereby achieving dynamic adjustment of the LED brightness. This design not only improves the stability and reliability of the system, but also ensures precise adjustment of the LED brightness under different temperature conditions, thereby achieving energy saving and extending the LED life.

[0085] Embodiment 4

[0086] In order to solve the problem of dynamic adjustment of LED current under different ambient temperatures, this embodiment further introduces an adaptive algorithm. Specifically, the steps of the simulated temperature control dimming method also include: dynamically adjusting the proportional coefficient through the adaptive algorithm to adapt to the dimming requirements under different ambient temperatures. The adjustment calculation formula of the proportional coefficient is:

[0087] K=K0·exp(-α·(TT ref ) 2 ], where K0 is the initial proportional coefficient, α is the adjustment factor, T is the current temperature, T ref is the reference temperature.

[0088] Furthermore, the initial proportionality coefficient K0 is usually set according to actual application requirements. In this embodiment, a fixed initial value can be selected, such as K0 = 0.1A / V. This initial value can be determined by experiments or simulations to ensure that the LED current changes within a reasonable range.

[0089] Furthermore, the adjustment factor α determines the sensitivity of the proportional coefficient K to temperature changes. In this embodiment, a suitable value may be selected, such as α=0.01. This value may be determined by experiments or simulations to ensure that the variation range of the proportional coefficient K under different temperature conditions is reasonable.

[0090] Furthermore, the reference temperature Tref Usually a standard operating temperature is selected, such as 25°C. This reference temperature can be adjusted according to the actual application environment to ensure that the system has the best performance at the most commonly used operating temperature.

[0091] Furthermore, the current temperature T is collected in real time through the NTC resistor. The specific implementation of the adaptive algorithm can be completed by a microcontroller or a dedicated digital signal processor (DSP). The microcontroller or DSP can periodically read the resistance value of the NTC resistor and calculate the current proportionality coefficient K according to the above formula. Then, the calculated proportionality coefficient is applied to the relationship between the LED current and the VFB voltage, thereby dynamically adjusting the LED current.

[0092] Furthermore, in order to improve the response speed and accuracy of the system, a temperature compensation algorithm can be added to the microcontroller or DSP. For example, the temperature characteristics of the NTC resistor can be calibrated by a table lookup method or a polynomial fitting method, thereby improving the accuracy of temperature measurement. In addition, a temperature filter can be added to the system to filter out noise in the temperature signal and improve the stability of temperature measurement.

[0093] Through the above design, the adaptive algorithm can dynamically adjust the proportional coefficient K according to the change of ambient temperature, so as to achieve accurate control of LED current. This can ensure that the LED brightness is always kept within the appropriate range under different temperature conditions, avoiding the problem of LED brightness decreasing in high temperature environment and LED brightness being too high in low temperature environment.

[0094] Embodiment 5

[0095] In order to solve the problem of temperature signal resolution and stability, and to prevent the state of Q1 from being frequently switched near the critical voltage value, this embodiment further optimizes the design of the temperature signal processing and control circuit. Specifically, the analog temperature control dimming method also includes:

[0096] A linear amplifier is used to amplify the temperature signal to improve the resolution and stability of the signal; a hysteresis comparator is set to prevent the state of Q1 from being frequently switched near the critical voltage value; and the change rate of the IFB voltage is adjusted to achieve smooth control of the LED brightness change.

[0097] In this embodiment, a high-performance operational amplifier such as OP07 or LM358 is selected. These operational amplifiers have the characteristics of low noise, high gain-bandwidth product and high input impedance, which can effectively improve the signal-to-noise ratio of the temperature signal, thereby improving the accuracy and reliability of the entire system. It should be understood that the specific parameters of the linear amplifier should be selected according to the actual application requirements.

[0098] Furthermore, the design of the hysteresis comparator can effectively prevent the state of Q1 from being frequently switched near the critical voltage value. The hysteresis comparator is usually composed of two different thresholds: one for triggering Q1 to turn on, and the other for triggering Q1 to turn off. In this embodiment, the positive threshold of the hysteresis comparator can be selected as Vth+ and the reverse threshold as Vth-. For example, Vth+=2.6V and Vth-=2.4V are set. This ensures that when the voltage at point A approaches the preset threshold, the state of Q1 will not switch frequently, thereby avoiding oscillation in the system.

[0099] Furthermore, in order to further improve the reliability and stability of the system, protection elements can be added to the circuit. For example, a TVS diode can be connected in parallel to the power input to absorb transient voltage shocks and protect the circuit from overvoltage damage. In addition, fuses or fuses can be added at key nodes to cut off the power supply in the event of a short circuit or other faults to protect the safety of the circuit.

[0100] The benefit of this embodiment is that the resolution and stability of the temperature signal are improved by using a linear amplifier, a hysteresis comparator is set to prevent frequent switching of the state of Q1, and the change rate of the IFB voltage is adjusted to achieve smooth control, thereby significantly improving the performance and reliability of the system.

[0101] Embodiment 6

[0102] In order to solve the problem of monitoring the actual change of LED current and accurately controlling it, this embodiment further introduces a feedback loop. Specifically, the analog temperature control dimming method introduces a feedback loop to monitor the actual change of LED current and fine-tune the IFB voltage according to the actual change to achieve more accurate brightness control. The feedback loop includes a current sensor and a PID controller, and the output of the PID controller is used to adjust the IFB voltage.

[0103] Furthermore, the selection of the current sensor is crucial for monitoring the LED current. In this embodiment, a Hall effect current sensor such as ACS712 is selected. This current sensor has the characteristics of high precision, low power consumption and fast response, and can accurately measure the LED current. It should be understood that the specific model of the current sensor should be selected according to the actual application requirements.

[0104] Further, the PID controller is used to adjust the IFB voltage according to the output signal of the current sensor. The three parameters (proportional, integral and differential) of the PID controller can be adjusted according to the actual application requirements. In this embodiment, the initial parameters can be set as: proportional coefficient Kp=0.5, integral coefficient Ki=0.01, differential coefficient Kd=0.05. These parameters can be optimized through experiments or simulations to ensure the best performance of the PID controller.

[0105] Furthermore, the specific implementation of the PID controller can be completed by a microcontroller or a dedicated digital signal processor (DSP). The microcontroller or DSP can periodically read the output signal of the current sensor and calculate the adjustment amount of the IFB voltage according to the PID control algorithm. Then, the calculated adjustment amount is applied to the IFB pin, thereby achieving accurate control of the LED current.

[0106] Furthermore, in order to improve the response speed and stability of the system, a feedforward control strategy can be added to the PID controller. The feedforward control strategy can adjust the IFB voltage in advance according to the change of the ambient temperature, thereby reducing the response time of the system. For example, a feedforward term can be added to the PID controller, and the feedforward term is adjusted according to the temperature signal of the NTC resistor.

[0107] The benefit of this embodiment is that by introducing a feedback loop to monitor the actual change of the LED current and using a PID controller for precise control, the performance and reliability of the system are significantly improved. This design not only improves the response speed and stability of the system, but also ensures the precise adjustment of the LED brightness under different temperature conditions. In this way, the system can maintain the stability of the LED brightness under various working environments, thereby improving the user's comfort and extending the service life of the LED. At the same time, the introduction of the feedback loop also enables the system to better cope with environmental changes.

[0108] Embodiment 7

[0109] In order to solve the specific implementation problem of the digital analog temperature control dimming circuit, this embodiment proposes a digital analog temperature control dimming circuit. Figure 2As shown in the figure, the analog temperature control dimming circuit includes input power VIN and COM which are rectified by a bridge rectifier composed of D1, D2, D3 and D4; the rectified DC power passes through an EMC filter composed of L2 and C1, C2 and C3 to reduce electromagnetic interference and noise; an LED driver chip including VIN, DIM, BST, SW and IFB pins; the VIN pin is connected to the power input terminal to provide the working voltage of the chip; the DIM pin is used to receive the PWM dimming signal; the BST pin is connected to a bootstrap circuit composed of R1 and C5 to improve the driving ability of the switch tube; the SW pin is connected to one end of L1 to generate a switch. The SW pin is used to detect and adjust the LED current through the LC filter composed of L1 and C7. RS1 and RS2 are used as current sampling resistors. The NTC thermistor is used to sense the ambient temperature. The NTC thermistor, R8 and R9 form a voltage divider network. When the voltage at point A reaches a certain threshold, the transistor Q1 is turned on. The gate of the transistor Q1 is connected to point A, the source is grounded, and the drain is connected to the IFB pin. When the transistor Q1 is turned on, the IFB voltage increases, which in turn affects the VFB voltage, thereby adjusting the LED current.

[0110] Furthermore, the bridge rectifier is composed of four diodes D1, D2, D3 and D4, and a diode of model 1N4007 is selected. This diode has the characteristics of high reverse withstand voltage and low forward voltage drop, and can effectively improve the rectification efficiency.

[0111] Furthermore, the EMC filter is composed of an inductor L2 and capacitors C1, C2, and C3, where L2 is a 10μH ferrite bead, and C1, C2, and C3 are ceramic capacitors of 10nF, 100nF, and 1μF, respectively. This combination can effectively filter out high-frequency noise and electromagnetic interference on the power line and improve the system's anti-interference ability.

[0112] Furthermore, the LED driver chip selects a high-performance driver chip model TPS92691. This chip has the characteristics of high efficiency, low power consumption and wide input voltage range, and is suitable for various LED applications. The VIN pin is directly connected to the rectified DC power supply to provide the operating voltage of the chip. The DIM pin receives an external PWM dimming signal to control the LED brightness. The BST pin is connected to a bootstrap circuit composed of R1 (10kΩ) and C5 (10nF) to improve the driving ability of the switch tube. The SW pin is connected to an LC filter composed of L1 (10μH) and C7 (100nF) and finally output to LED1 and LED2. This design can effectively reduce switching noise and improve the driving stability of the LED.

[0113] Furthermore, current sampling resistors RS1 and RS2 are respectively selected as 0.1Ω precision resistors to monitor the actual change of LED current. These resistors have low temperature coefficient and high precision, and can accurately measure LED current. The IFB pin feeds back the voltage across the current sampling resistor to the LED driver chip through a feedback loop, thereby achieving accurate control of the LED current.

[0114] Furthermore, the NTC thermistor selects a high-precision NTC resistor of model NTC10K-470, which forms a voltage divider network with R8 (10kΩ) and R9 (5kΩ). When the voltage at point A reaches the preset threshold, transistor Q1 is turned on, the IFB voltage increases, which in turn affects the VFB voltage, thereby adjusting the LED current. Transistor Q1 selects a MOSFET of model 2N7000, with its gate connected to point A, the source grounded, and the drain connected to the IFB pin. This design can effectively respond to changes in ambient temperature and achieve dynamic adjustment of LED brightness.

[0115] The benefit of this embodiment is that by optimizing the design of the bridge rectifier, EMC filter, LED driver chip and its peripheral circuits, the stability and anti-interference ability of the system are significantly improved. At the same time, by accurately selecting the NTC thermistor and the current sampling resistor, the LED current is accurately controlled. Not only the response speed of the system is improved, but also the accurate adjustment of the LED brightness under different temperature conditions is ensured.

[0116] Embodiment 8

[0117] In order to solve the problem of generating the voltage reference at point A and controlling the on and off of Q1, this embodiment further refines the generation method of the voltage at point A and its influence on the LED current. Specifically, the voltage at point A forms a reference voltage through R7 and D5; when the voltage at point A reaches the preset threshold, Q1 is turned on, the IFB voltage increases, the VFB voltage decreases, the LED current decreases, and the brightness decreases; when the voltage at point A decreases below the preset threshold, Q1 is turned off, the IFB voltage decreases, the VFB voltage increases, the LED current increases, and the brightness increases; RS1 and RS2 are used as current sampling resistors to monitor the actual changes in the LED current; the voltage across the current sampling resistor is fed back to the IFB pin of the LED driver chip to more accurately control the brightness.

[0118] Furthermore, the voltage at point A is a reference voltage formed by R7 (10kΩ) and D5 (1N4148). R7 is a 10kΩ precision resistor and D5 is a 1N4148 diode. This combination can provide a stable reference voltage. It should be understood that the stability of the reference voltage is critical to the precise control of the system.

[0119] Furthermore, when the voltage at point A reaches a preset threshold, transistor Q1 is turned on. Q1 can be a 2N7000 MOSFET, with its gate connected to point A, source grounded, and drain connected to the IFB pin. When Q1 is turned on, the IFB voltage increases, which in turn affects the VFB voltage, resulting in a decrease in LED current and brightness. This design can effectively respond to changes in ambient temperature and achieve dynamic adjustment of LED brightness.

[0120] Furthermore, when the voltage at point A drops below the preset threshold, Q1 turns off. At this time, the IFB voltage drops, the VFB voltage rises, the LED current increases, and the brightness increases. This design ensures that the LED brightness can be automatically adjusted under different temperature conditions and maintained within the appropriate range.

[0121] Furthermore, current sampling resistors RS1 and RS2 are respectively selected as 0.1Ω precision resistors to monitor the actual changes of LED current. These resistors have low temperature coefficient and high precision, and can accurately measure the LED current. The voltage across the current sampling resistor is fed back to the IFB pin of the LED driver chip, thereby achieving precise control of the LED current. This feedback mechanism can monitor the changes of LED current in real time and adjust it according to actual needs to ensure the stability of LED brightness.

[0122] Furthermore, in order to improve the response speed and stability of the system, a small capacitor (such as 100pF) can be connected in parallel at both ends of the current sampling resistor to filter out high-frequency noise in the current signal. In addition, a small resistor (such as 1kΩ) can be connected in parallel between the gate and source of Q1 to limit the speed of gate charging and discharging, thereby further slowing down the switching speed of Q1 state. This design can effectively reduce system oscillation and improve system stability.

[0123] The benefit of this embodiment is that by accurately generating the voltage reference at point A and dynamically adjusting the LED current through the on and off control of Q1, the stability and response speed of the system are significantly improved. At the same time, by introducing the current sampling resistor and feedback mechanism, the LED current is accurately controlled.

[0124] Embodiment 9

[0125] In order to solve the specific implementation problem of the digital analog temperature control dimming system, the present embodiment provides a digital analog temperature control dimming system. Specifically, the analog temperature control dimming system includes a temperature signal acquisition module, which is used to collect the ambient temperature signal through the NTC resistor; a signal conversion module, which is electrically connected to the temperature signal acquisition module, and is used to convert the temperature signal into a voltage signal; a voltage detection module, which is electrically connected to the signal conversion module, and is used to detect whether the voltage signal reaches a preset threshold; a voltage control module, which is electrically connected to the voltage detection module, and is used to control the IFB voltage according to the change of the voltage signal; a current control module, which is electrically connected to the voltage control module, and is used to control the LED current according to the change of the IFB voltage.

[0126] Furthermore, the temperature signal acquisition module uses a high-precision NTC resistor of model NTC10K-470. This NTC resistor has good linearity and stability and can provide reliable temperature measurement over a wide temperature range. The temperature signal acquisition module collects the ambient temperature signal through the NTC resistor and transmits it to the signal conversion module.

[0127] Furthermore, the signal conversion module uses high-performance operational amplifiers such as OP07 or LM358. These operational amplifiers have the characteristics of low noise, high gain bandwidth product and high input impedance, which can effectively improve the signal-to-noise ratio of the temperature signal, thereby improving the accuracy and reliability of the entire system. The signal conversion module converts the temperature signal into a voltage signal and passes it to the voltage detection module.

[0128] Furthermore, the current control module uses an LED driver chip such as TPS92691. This chip has the characteristics of high efficiency, low power consumption and wide input voltage range, and is suitable for various LED applications. The current control module controls the LED current according to the change of IFB voltage. The IFB pin feeds back the voltage across the current sampling resistor to the LED driver chip through a feedback loop, thereby achieving precise control of the LED current. The current control module achieves dynamic adjustment of the LED brightness by adjusting the IFB voltage.

[0129] Furthermore, in order to improve the stability of the system, protection elements can be added between the modules. For example, a TVS diode can be connected in parallel at the power input to absorb transient voltage shocks and protect the circuit from overvoltage damage. In addition, fuses or fuses can be added at key nodes to cut off the power supply in the event of a short circuit or other faults to protect the safety of the circuit.

[0130] The benefit of this embodiment is that the stability of the system is significantly improved through modular design and optimization of the functions of each module. The coordinated work between the temperature signal acquisition module, the signal conversion module, the voltage detection module, the voltage control module and the current control module ensures the precise adjustment of the LED brightness under different temperature conditions.

[0131] Embodiment 10

[0132] In order to solve the software implementation problem of the digital analog temperature control dimming method, this embodiment further optimizes the computer program stored on the storage medium. Specifically, the storage medium stores a computer program, and when the computer program is executed by the processor, the digital analog temperature control dimming method is implemented.

[0133] Furthermore, the computer program mainly includes the following functional modules: temperature signal acquisition module, signal conversion module, voltage detection module, voltage control module and current control module. Each module realizes its function through a corresponding algorithm. The temperature signal acquisition module acquires the ambient temperature signal through an NTC resistor and passes it to the signal conversion module. The signal conversion module converts the temperature signal into a voltage signal and passes it to the voltage detection module. The voltage detection module detects whether the voltage signal reaches a preset threshold and passes the detection result to the voltage control module. The voltage control module calculates the adjustment amount of the IFB voltage according to the change of the voltage signal and performs precise control through the PID control algorithm. The current control module controls the LED current according to the change of the IFB voltage.

[0134] Furthermore, the temperature signal acquisition module reads the resistance value of the NTC resistor and converts it into a temperature value according to the characteristic curve of the NTC resistor. The signal conversion module amplifies the temperature signal through an operational amplifier and converts it into a voltage signal. The voltage detection module detects whether the voltage signal reaches a preset threshold through a hysteresis comparator. The voltage control module implements the PID control algorithm through a microcontroller or DSP to calculate the adjustment amount of the IFB voltage. The current control module realizes precise control of the LED current through the LED driver chip.

[0135] Furthermore, in order to improve the response speed and stability of the system, a feedforward control strategy can be added to the computer program. The feedforward control strategy can adjust the IFB voltage in advance according to the change of the ambient temperature, thereby reducing the response time of the system. For example, a feedforward term can be added to the PID controller, and the feedforward term is adjusted according to the temperature signal of the NTC resistor.

[0136] The benefit of this embodiment is that by optimizing the computer program stored on the storage medium, the software implementation of the digital analog temperature control dimming method is achieved.

[0137] Although the present invention has been specifically described above with reference to the preferred embodiments of the present invention, it is to be understood that the present invention is not limited to the embodiments described above. Instead, various modifications and changes may be made by those skilled in the art without departing from the essence of the present invention, and these modifications and changes should fall within the scope defined by the attached claims and their equivalents.

Claims

1. A digital analog temperature control dimming method, characterized in that: The following steps are involved: The ambient temperature signal is collected in real time through the temperature sensing NTC resistor, and the temperature signal is converted into a resistance value inversely proportional to the temperature; Convert the NTC resistance value into a voltage signal through a voltage divider network, and transmit the voltage signal to a reference voltage control point A, wherein the voltage at point A changes with the NTC resistance value; When the voltage at point A rises to a preset threshold, the transistor Q1 is triggered to turn on, causing the IFB voltage to start rising; As the IFB voltage increases, the feedback mechanism inside the LED driver chip reduces the VFB voltage, thereby reducing the LED current and achieving a reduction in brightness; When the voltage at point A drops below a preset threshold, the transistor Q1 is triggered to turn off, the IFB voltage drops, the VFB voltage rises, and the LED current increases, thereby increasing the brightness.

2. The digital analog temperature control dimming method according to claim 1, characterized in that: The voltage divider network consists of an NTC resistor, resistors R8 and R9, and the preset threshold is calculated as follows: Among them, V th is the preset threshold, V ref is a reference voltage, and R8 and R9 represent the resistance values ​​of the resistors R8 and R9 respectively.

3. The digital analog temperature control dimming method according to claim 2, characterized in that: The relationship between the LED current and the VFB voltage is: I LED =K*(V ref -VFB), where I LED is the LED current, K is the proportionality coefficient.

4. The digital analog temperature control dimming method according to claim 3, characterized in that: The steps of the analog temperature control dimming method also include: The proportional coefficient is dynamically adjusted through an adaptive algorithm to adapt to the dimming requirements under different ambient temperatures. The adjustment calculation formula of the proportional coefficient is: K=K0·exp[-α·(TT ref ) 2 ], where K0 is the initial proportional coefficient, α is the adjustment factor, T is the current temperature, T ref is the reference temperature.

5. The digital analog temperature control dimming method according to claim 1, characterized in that: The analog temperature control dimming method also includes: A linear amplifier is used to amplify the temperature signal to improve the resolution and stability of the signal; A hysteresis comparator is set to prevent frequent switching of the state of Q1 near the critical voltage value; By adjusting the change rate of the IFB voltage, smooth control of LED brightness changes can be achieved.

6. The digital analog temperature control dimming method according to claim 1, characterized in that: The analog temperature-controlled dimming method introduces a feedback loop for monitoring the actual change of LED current and fine-tuning the IFB voltage according to the actual change to achieve more accurate brightness control; the feedback loop includes a current sensor and a PID controller, and the output of the PID controller is used to adjust the IFB voltage.

7. A digital analog temperature control dimming circuit, used to implement the digital analog temperature control dimming method according to any one of claims 1 to 6, characterized in that: The analog temperature-controlled dimming circuit comprises: The input power VIN and COM are rectified by a bridge rectifier composed of D1, D2, D3 and D4; The rectified DC power passes through the EMC filter composed of L2 and C1, C2, and C3 to reduce electromagnetic interference and noise; An LED driver chip, including VIN, DIM, BST, SW, and IFB pins; The VIN pin is connected to the power input terminal to provide the operating voltage of the chip; The DIM pin is used to receive the PWM dimming signal; The BST pin uses a bootstrap circuit composed of R1 and C5 to improve the driving ability of the switch tube; The SW pin is connected to one end of L1 to generate a switch signal to drive the LED; The IFB pin is used to detect the LED current and adjust it; In the LED output part, the SW pin passes through the LC filter composed of L1 and C7, and finally outputs to LED1 and LED2. RS1 and RS2 are used as current sampling resistors; NTC thermistor, used to sense ambient temperature; The NTC thermistor, R8 and R9 form a voltage divider network. When the voltage at point A reaches a certain threshold, transistor Q1 is turned on. The gate of transistor Q1 is connected to point A, the source is grounded, and the drain is connected to the IFB pin. When transistor Q1 is turned on, the IFB voltage increases, which in turn affects the VFB voltage, thereby adjusting the LED current.

8. The digital analog temperature control dimming circuit as claimed in claim 7, characterized in that: The voltage at point A forms a reference voltage through R7 and D5; When the voltage at point A reaches the preset threshold, Q1 is turned on, the IFB voltage increases, the VFB voltage decreases, the LED current decreases, and the brightness decreases; When the voltage at point A drops below the preset threshold, Q1 turns off, the IFB voltage drops, the VFB voltage rises, the LED current increases, and the brightness increases; RS1 and RS2 are used as current sampling resistors to monitor the actual changes of LED current; The voltage across the current sampling resistor is fed back to the IFB pin of the LED driver chip to more accurately control the brightness.

9. A digital analog temperature control dimming system, used to implement the digital analog temperature control dimming method according to any one of claims 1 to 6, characterized in that: The analog temperature control dimming system comprises: Temperature signal acquisition module, used to collect ambient temperature signals through NTC resistors; A signal conversion module, electrically connected to the temperature signal acquisition module, and used for converting the temperature signal into a voltage signal; A voltage detection module, electrically connected to the signal conversion module, for detecting whether the voltage signal reaches a preset threshold; a voltage control module, electrically connected to the voltage detection module, and configured to control the IFB voltage according to a change of the voltage signal; The current control module is electrically connected to the voltage control module and is used to control the LED current according to the change of the IFB voltage.

10. A storage medium, characterized in that: The storage medium stores a computer program, and when the computer program is executed by the processor, the digital analog temperature control dimming method according to any one of claims 1 to 6 is implemented.

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