A radar sensing LED driving circuit

Abstract

The utility model discloses a radar response LED drive circuit, including rectification filter circuit, active power factor correction boost circuit, BUCK voltage reducing circuit and radar control module that connect gradually. Rectification filter circuit converts alternating current commercial power into direct current, active power factor correction boost circuit improves power factor and exports stable high pressure, BUCK voltage reducing circuit receives PWM signal regulation output current, and radar control module senses environmental illumination and locks corresponding PWM parameter, and triggers signal output when detecting human activity. The utility model solves the single of the technical problem of the prior art radar LED lamp light modulation mode, and power factor is low and the technical problem of low efficiency.

Description

Technical Field

[0001] This utility model relates to the field of LED lighting technology, and in particular to a radar-sensing LED driving circuit. Background Technology

[0002] With the development of intelligent lighting technology, radar-sensing LED lights have been widely used in the market due to their strong anti-interference ability and high sensing sensitivity. However, most radar-sensing lights on the market currently have a relatively simple dimming mode, usually only having two working states: "full brightness when people are present, full brightness when people leave" or "full brightness when people are present, dim brightness when people leave." This kind of control method, which is either on or off or changes in brightness abruptly, cannot smoothly and precisely adjust the brightness according to the continuous changes in ambient natural illuminance, resulting in the following defects: First, during periods of transition in ambient light, such as dusk or dawn, the lights cannot provide matching illumination brightness, and sudden changes in light can easily cause visual discomfort to users, affecting the user experience; second, operating at full power when the ambient light is still acceptable results in unnecessary energy waste, which contradicts the concept of green energy saving. In terms of circuit architecture, existing high power factor LED drivers often use a single-stage flyback topology. Although it can achieve power factor correction (active power factor correction), its output terminal usually requires a large number of electrolytic capacitors to suppress flicker, resulting in a large size, high cost, and limited lifespan of the driver power supply. Meanwhile, single-stage solutions are relatively inefficient and generate significant heat, requiring large-area heat dissipation structures, which further limits their use in applications that prioritize miniaturization and high reliability.

[0003] Therefore, there is an urgent need for a radar-sensing LED driver circuit that can steplessly adjust brightness according to ambient illuminance, has a high power factor, and is highly efficient. Utility Model Content

[0004] The main purpose of this invention is to propose a radar-sensing LED driving circuit, which aims to solve the technical problems of existing radar LED lights having a single dimming mode, low power factor, and low efficiency.

[0005] To achieve the above objectives, the first aspect of this utility model proposes a radar-sensing LED driving circuit, including a rectifier and filter circuit, an active power factor correction boost circuit, a buck circuit, and a radar control module. The input terminal of the rectifier and filter circuit is connected to AC mains power to rectify and filter the AC power into DC power. The input terminal of the active power factor correction boost circuit is connected to the output terminal of the rectifier and filter circuit to improve the power factor and output a stable high voltage. The input terminal of the buck circuit is connected to the output terminal of the active power factor correction boost circuit, and its output terminal is used to connect to an LED load. The buck circuit has a PWM signal input terminal for receiving a PWM signal to regulate the current output to the LED load. The input terminal of the radar control module is connected to the output terminal of the rectifier and filter circuit, and its output terminal is connected to the PWM signal input terminal of the buck circuit. The radar control module is used to sense ambient illuminance and lock the corresponding PWM signal parameters, and to trigger the output of the locked PWM signal when human movement is sensed.

[0006] Preferably, the rectifier-filter circuit includes a first inductor, a first resistor, a first capacitor, a second capacitor, a common-mode inductor, and a rectifier bridge; the input terminal of the common-mode inductor is connected to AC mains power, and the output terminal is connected to the AC input terminal of the rectifier bridge; the DC output terminal of the rectifier bridge is connected to the first terminal of the first inductor, the first terminal of the first resistor, and the first terminal of the first capacitor; the second terminal of the first inductor is connected to the second terminal of the first resistor and the first terminal of the second capacitor, and the second terminals of the first capacitor and the second terminal of the second capacitor are grounded.

[0007] Preferably, the rectifier filter circuit further includes a fuse, a safety capacitor, and a varistor; the fuse is connected in series between the mains live wire L and the input terminal of the common mode inductor; the safety capacitor is connected in parallel between the mains live wire L and the neutral wire N; and the varistor is connected in parallel between the two output terminals of the common mode inductor.

[0008] Preferably, the active power factor correction boost circuit includes an active power factor correction control chip, a second inductor, a first diode, and a third capacitor; the first end of the second inductor is connected to the output terminal of the rectifier-filter circuit, and the second end is connected to the output terminal of the active power factor correction control chip; the first input terminal of the active power factor correction control chip is connected to the output terminal of the rectifier-filter circuit; the anode of the first diode is connected to the second end of the second inductor, and the cathode is connected to the first end of the third capacitor and serves as the output terminal of the active power factor correction boost circuit; the second end of the third capacitor is grounded.

[0009] Preferably, the active power factor correction boost circuit further includes a startup resistor network, a voltage feedback resistor network, and a fourth capacitor; the first end of the startup resistor network is connected to the output end of the rectifier filter circuit, the second end is connected to the first input end of the active power factor correction control chip and the first end of the fourth capacitor, and the second end of the fourth capacitor is grounded; the first end of the voltage feedback resistor network is connected to the cathode of the first diode, and the second end is grounded; the second input end of the active power factor correction control chip is connected to the sampling node of the voltage feedback resistor network.

[0010] Preferably, the active power factor correction boost circuit further includes a current feedback resistor network, a second diode, and a fifth capacitor; the current feedback resistor network is connected between the third input terminal of the active power factor correction control chip and ground; the first terminal of the second diode and the first terminal of the fifth capacitor are connected to the first terminal of the second inductor; the second terminal of the second diode and the second terminal of the fifth capacitor are connected to the cathode of the first diode.

[0011] Preferably, the BUCK step-down circuit includes an LED constant current driver chip, a third inductor, and a third diode; the first input terminal of the LED constant current driver chip is connected to the output terminal of the active power factor correction boost circuit, the second input terminal is connected to the output terminal of the radar control module, and the output terminal is connected to the first terminal of the third inductor and the anode of the third diode; the cathode of the third diode is connected to the output terminal of the active power factor correction boost circuit and the positive terminal of the LED load; the second terminal of the third inductor is connected to the negative terminal of the LED load.

[0012] Preferably, the BUCK step-down circuit further includes a sixth capacitor, a seventh capacitor, a second resistor, and a third resistor; the sixth capacitor and the second resistor are connected in parallel between the positive terminal of the third diode and the second terminal of the third inductor; the seventh capacitor and the third resistor are connected in parallel between the second input terminal of the LED constant current driver chip and ground.

[0013] Preferably, the BUCK step-down circuit further includes a second current feedback resistor network, a fourth resistor, and a fifth resistor; the first end of the second current feedback resistor network is connected to the third input terminal of the LED constant current driver chip, and the second end is grounded; the first input terminal of the LED constant current driver chip is connected to the output terminal of the active power factor correction boost circuit through the fourth resistor; the fourth input terminal of the LED constant current driver chip is grounded through the fifth resistor.

[0014] Preferably, the system further includes an auxiliary power supply circuit, which comprises a step-down control chip, a fourth inductor, an eighth capacitor, a ninth capacitor, a tenth capacitor, and a sixth resistor. The first input terminal of the step-down control chip is connected to the output terminal of the rectifier-filter circuit, the second input terminal is connected to the first terminal of the fourth inductor and the first terminal of the ninth capacitor, the third input terminal is connected to the second terminal of the ninth capacitor, and the output terminal is connected to the second terminal of the fourth inductor, the first terminal of the tenth capacitor, the first terminal of the sixth resistor, and the input terminal of the radar control module. The first terminal of the eighth capacitor is connected to the output terminal of the rectifier-filter circuit, and the second terminal is grounded. The second terminals of the tenth capacitor and the second terminals of the sixth resistor are grounded.

[0015] This invention proposes a radar-sensing LED driving circuit that improves the efficiency of power grid utilization and reduces harmonic pollution through active power factor correction technology; improves the accuracy and stability of output current control through BUCK buck topology combined with PWM dimming technology; achieves intelligent segmented adjustment of lighting brightness through coordinated control of radar sensing and ambient light perception; and significantly reduces the size of the driving circuit and lowers system cost while meeting high power factor requirements through multi-level circuit collaborative operation.

[0016] Furthermore, this utility model also improves EMI performance by suppressing electromagnetic interference through common-mode inductors; enhances surge current suppression by forming an active damping circuit using inductors and resistors in parallel; improves power quality stability by smoothing DC waveforms through a π-type filter network; enhances overcurrent protection reliability through series fuse protection; improves differential-mode interference suppression by parallel filtering with safety capacitors; enhances lightning surge protection level through parallel protection with varistors; improves power factor and energy utilization efficiency by shaping current waveforms through an active power factor correction control chip; improves boost conversion efficiency by achieving energy conversion through the coordinated work of inductors and switching elements; improves the stability and reliability of DC output voltage through output capacitor filtering and voltage regulation; improves circuit startup reliability by providing initial operating voltage through a startup resistor network; improves voltage regulation control accuracy by accurately sampling output voltage through a voltage feedback network; improves chip operating stability by optimizing power supply quality through a VCC pin filter capacitor; improves current detection accuracy and reliability by accurately sampling switching current through a current feedback resistor network; and improves current detection accuracy and reliability through diodes and... The capacitor combination absorbs high-frequency noise, improving electromagnetic compatibility performance; the LED constant current driver chip receives PWM signals to precisely adjust the duty cycle, improving output current control accuracy and dimming light performance; a step-down inductor achieves efficient energy conversion, improving overall system efficiency; a freewheeling diode provides a current loop, improving circuit stability and reliability; a parallel RC network at the output end filters high-frequency ripple, improving LED load current stability; a parallel RC filter network at the PWM signal end suppresses interference, improving dimming signal noise immunity and reliability; a second current feedback resistor network precisely samples the output current, improving constant current control accuracy; a fourth resistor limits high-voltage input current, improving chip input protection capability; a fifth resistor sets the overvoltage protection threshold, improving safety when the output is open-circuited; a non-isolated step-down architecture directly converts high-voltage DC, improving power conversion efficiency; inductor and capacitor synergistic filtering improves output voltage stability; feedback resistors precisely set voltage values, improving output accuracy; and a multi-stage capacitor filtering design improves power supply anti-interference capability.

[0017] In summary, this invention solves the technical problems of existing radar LED lights, such as single dimming mode, low power factor, and low efficiency. Attached Figure Description

[0018] To more clearly illustrate the technical solutions in the embodiments of this utility model or the prior art, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are only some embodiments of this utility model. For those skilled in the art, other drawings can be obtained based on the structures shown in these drawings without creative effort.

[0019] Figure 1 A circuit block diagram of a radar-sensing LED driving circuit provided in an embodiment of this utility model; Figure 2 A circuit block diagram of another radar-sensing LED driving circuit provided in an embodiment of this utility model; Figure 3 A circuit diagram of a rectifier and filter circuit provided in an embodiment of this utility model; Figure 4 A circuit diagram of an active power factor correction boost circuit provided in an embodiment of this utility model; Figure 5 A circuit diagram of a BUCK step-down circuit provided in an embodiment of this utility model; Figure 6 A circuit diagram of a radar control module provided in an embodiment of this utility model; Figure 7 The circuit diagram of the auxiliary power supply circuit provided in one embodiment of this utility model.

[0020] In the attached diagram: 1-rectifier and filter circuit, 2-active power factor correction boost circuit, 3-BUCK buck circuit, 4-radar control module, 5-auxiliary power supply circuit.

[0021] The realization of the purpose, functional features and advantages of this utility model will be further explained in conjunction with the embodiments and with reference to the accompanying drawings. Detailed Implementation

[0022] The technical solutions of the present utility model will be clearly and completely described below with reference to the accompanying drawings of the embodiments. Obviously, the described embodiments are only some embodiments of the present utility model, and not all embodiments. Based on the embodiments of the present utility model, all other embodiments obtained by those skilled in the art without creative effort are within the protection scope of the present utility model.

[0023] It should be noted that if the embodiments of this utility model involve directional indicators, such as up, down, left, right, front, back, etc., the directional indicators are only used to explain the relative positional relationship and movement of the components in a specific posture. If the specific posture changes, the directional indicators will also change accordingly.

[0024] Furthermore, if the embodiments of this utility model involve descriptions such as "first" or "second," these descriptions are for descriptive purposes only and should not be construed as indicating or implying their relative importance or implicitly specifying the number of technical features indicated. Therefore, a feature defined with "first" or "second" may explicitly or implicitly include at least one of those features. Additionally, the technical solutions of the various embodiments can be combined with each other, but this must be based on the ability of those skilled in the art to implement them. When the combination of technical solutions is contradictory or impossible to implement, it should be considered that such a combination of technical solutions does not exist and is not within the scope of protection claimed by this utility model.

[0025] The main purpose of this invention is to propose a radar-sensing LED driving circuit, which aims to solve the technical problems of existing radar LED lights having a single dimming mode, low power factor, and low efficiency.

[0026] like Figures 1 to 7 As shown, this utility model proposes a radar-sensing LED driving circuit, including a rectifier and filter circuit 1, an active power factor correction boost circuit 2, a BUCK buck circuit 3, and a radar control module 4. The input terminal of the rectifier and filter circuit 1 is connected to AC mains power to rectify and filter AC power into DC power. The input terminal of the active power factor correction boost circuit 2 is connected to the output terminal of the rectifier and filter circuit 1 to improve the power factor and output a stable high voltage. The input terminal of the BUCK buck circuit 3 is connected to the output terminal of the active power factor correction boost circuit 2, and the output terminal is used to connect to the LED load. The BUCK buck circuit 3 has a PWM signal input terminal to receive PWM signals to adjust the current output to the LED load. The input terminal of the radar control module 4 is connected to the output terminal of the rectifier and filter circuit 1, and the output terminal is connected to the PWM signal input terminal of the BUCK buck circuit 3. The radar control module 4 is used to sense ambient illuminance and lock the corresponding PWM signal parameters, and to trigger the output of the locked PWM signal when human movement is sensed. In this embodiment, the radar model is EDC18F-50Y. This radar module integrates a high-sensitivity millimeter-wave radar sensor and a photosensitive sensing unit, which can detect ambient light intensity and sense human movement in real time. Through the internal microprocessor, it intelligently analyzes the sensing data and automatically generates a PWM control signal that matches the ambient light level according to a preset algorithm. When human activity is detected, it immediately outputs a PWM signal with the corresponding duty cycle to the BUCK step-down circuit.

[0027] Understandably, this embodiment improves the efficiency of power grid utilization and reduces harmonic interference through active power factor correction technology; achieves intelligent segmented adjustment of lighting brightness through coordinated control of radar sensing and ambient light sensing; improves the control accuracy and stability of output current through BUCK buck topology combined with pulse width modulation technology; and achieves the unity of high-efficiency energy saving and intelligent lighting through multi-module collaborative operation.

[0028] Preferred, such as Figure 3 As shown, in a specific embodiment of this utility model, the rectifier filter circuit 1 includes a first inductor L1, a first resistor R1, a first capacitor C1, a second capacitor C2, a common-mode inductor LF1, and a rectifier bridge DB1. The two input terminals of the common-mode inductor LF1 are respectively connected to the live wire L and the neutral wire N of the AC mains, and the two output terminals are respectively connected to the two AC input terminals of the rectifier bridge DB1. The positive DC output terminal of the rectifier bridge DB1 is simultaneously connected to the first terminal of the first inductor L1, the first terminal of the first resistor R1, and the first terminal of the first capacitor C1. The second terminal of the first inductor L1 is connected to the second terminal of the first resistor R1 and the first terminal of the second capacitor C2, forming an active damping filter network. The second terminal of the first capacitor C1 and the second terminal of the second capacitor C2 are grounded together, and the negative DC output terminal of the rectifier bridge DB1 is also grounded. Specifically, the mains input is filtered by the common-mode inductor LF1 to remove common-mode interference before being fed into the rectifier bridge DB1 for full-wave rectification. The pulsating DC power obtained after rectification is smoothed by an LC filter network composed of the first inductor L1, the first capacitor C1, and the second capacitor C2. The first resistor R1 is connected in parallel with the first inductor L1 to form an active damping circuit, which effectively suppresses the peak inrush current generated at the moment of power-on and avoids damage to the subsequent circuits. At the same time, the first capacitor C1 and the second capacitor C2 are connected in parallel to enhance the filtering effect, together providing a relatively smooth and stable DC power supply for the subsequent circuits.

[0029] Understandably, this embodiment uses a first resistor and a first inductor connected in parallel to form an active damping network, which improves the ability to suppress surge current and ensures circuit startup safety; the common-mode inductor works in conjunction with the rectifier bridge to improve electromagnetic compatibility performance and reduce interference to the power grid; and the LC filter network works in conjunction with the active damping to improve DC power quality and provide stable operating conditions for the subsequent power factor correction circuit.

[0030] Those skilled in the art can make corresponding equivalent improvements based on the application scenario, such as: replacing the common-mode inductor with other forms of electromagnetic interference filtering devices; adjusting the parallel parameter values ​​of the inductor and resistor; using rectifier bridges of different specifications; or changing the capacitance ratio of the first capacitor and the second capacitor to optimize the filtering characteristics.

[0031] Preferred, such as Figure 3As shown in a specific embodiment of this utility model, the rectifier filter circuit 1 further includes a fuse F1, a safety capacitor CX1, and a varistor RV1. The fuse F1 is connected in series between the mains live wire L and the input terminal of the common-mode inductor LF1 to form overcurrent protection. The safety capacitor CX1 is connected in parallel between the mains live wire L and the neutral wire N to filter out differential-mode interference in the power grid. The varistor RV1 is connected in parallel between the two output terminals of the common-mode inductor LF1, that is, across the AC input terminals of the rectifier bridge DB1, and can quickly conduct to absorb overvoltage when encountering lightning strikes or power grid surges. These protective components work together with the common-mode inductor LF1 and the rectifier bridge DB1 to provide multiple protections before the AC power enters the rectification stage, ensuring that the subsequent circuits are not affected by abnormal power grid conditions.

[0032] Understandably, this embodiment improves overcurrent protection reliability by connecting a fuse in series with the live wire circuit; improves differential mode interference suppression capability by connecting a safety capacitor in parallel with the input line; and improves lightning surge protection level by connecting a varistor in parallel with the rectifier preamp.

[0033] Those skilled in the art can make corresponding equivalent improvements based on the application scenario, such as: replacing the fuse with a resettable fuse to provide an automatic recovery function; or using safety capacitors with different withstand voltage ratings to adapt to different power grid environments; or selecting varistor devices with different conduction voltages; or using a gas discharge tube in series with a varistor to enhance the protection effect.

[0034] Preferred, such as Figure 4 As shown, in a specific embodiment of this utility model, the active power factor correction boost circuit 2 includes an active power factor correction control chip U1, a second inductor L2, a first diode D2, and a third capacitor EC2. The active power factor correction control chip U1 is a BP2636. The first end of the second inductor L2 is connected to the output end of the rectifier filter circuit 1 (the second end of the first inductor L1) to obtain DC power, and the second end is connected to the output DRAIN pin of the active power factor correction control chip U1. In this embodiment, the second end is also connected to all four DRAIN pins of the active power factor correction control chip U1. The first input VCC pin of the active power factor correction control chip U1 is connected to the output end of the rectifier filter circuit 1 (the second end of the first inductor L1) to obtain the operating voltage. The anode of the first diode D2 is connected to the second end of the second inductor L2, and the cathode is connected to the first end of the third capacitor EC2 and serves as the output end of the active power factor correction boost circuit 2. The second end of the third capacitor EC2 is grounded. In this embodiment, the active power factor correction control chip U1 drives the second inductor L2 to store and release energy through the above connection method. It works with the first diode D2 and the third capacitor EC2 to complete the boost and filtering functions, and finally outputs a stable high-voltage DC.

[0035] Understandably, this embodiment improves power factor correction accuracy by adjusting the switching timing in real time through a dedicated control chip; improves voltage conversion efficiency through energy transfer via inductor energy storage and release; improves the stability of DC output voltage through output capacitor filtering; and improves chip heat dissipation and current carrying capacity through multi-pin parallel DRAIN connection.

[0036] Those skilled in the art can make corresponding equivalent improvements based on the application scenario, such as: replacing the active power factor correction control chip with other PFC control chip models with the same function; or replacing the diode with a Schottky diode to reduce conduction loss; or using power inductors with different core materials; or using electrolytic capacitors or film capacitors with different capacitance values ​​as output filter capacitors.

[0037] Preferred, such as Figure 4 As shown in a specific embodiment of this utility model, the active power factor correction boost circuit 2 further includes a startup resistor network, a voltage feedback resistor network, and a fourth capacitor EC1. The first end of the startup resistor network is connected to the output terminal of the rectifier filter circuit 1, and the second end is connected to the first input terminal VCC pin of the active power factor correction control chip U1 to provide the chip with an initial startup operating voltage. The first end of the fourth capacitor EC1 is connected to the first input terminal VCC pin of the active power factor correction control chip U1, and the second end is grounded, serving as a filter and energy storage device to ensure stable power supply to the chip. The first end of the voltage feedback resistor network is connected to the cathode of the first diode D2, and the second end is grounded. The second input terminal FB pin of the active power factor correction control chip U1 is connected to the sampling node of the voltage feedback resistor network. Specifically, in this embodiment, the startup resistor network includes resistors R2 and R3 connected in series, and the voltage feedback resistor network includes resistors R4, R5, and R6 connected in series. The connection point of resistors R4 and R5 is the sampling node. Resistor R4 is connected between the FB pin and ground. Resistor R5 and R6 are connected in series between the output terminal (cathode of the first diode D2) of the active power factor correction boost circuit 2 and the FB pin. At the same time, a compensation capacitor C4 is also connected between the FB pin and ground, forming a complete voltage feedback and compensation network.

[0038] Understandably, this embodiment provides the initial operating voltage to the control chip through a startup resistor network, thereby improving the reliability of circuit startup; samples the output voltage through a precision resistor network, thereby improving the accuracy of voltage regulation control; and optimizes the feedback loop response characteristics through a compensation capacitor, thereby improving system stability.

[0039] Those skilled in the art can make corresponding equivalent improvements based on the application scenario, such as: adjusting the value of the start-up resistor to adapt to different input voltage ranges; or changing the ratio of the feedback resistor to set different output voltage values; or using different types of compensation capacitors to optimize the loop response; or using an adjustable resistor to replace the fixed resistor to facilitate output voltage calibration.

[0040] Preferred, such as Figure 4 As shown, in a specific embodiment of this utility model, the active power factor correction boost circuit 2 further includes a current feedback resistor network, a second diode D1, and a fifth capacitor C3. The current feedback resistor network is connected between the third input terminal CS pin of the active power factor correction control chip U1 and ground, and is used to detect the switching current and realize overcurrent protection. In this embodiment, the current feedback resistor network includes resistors RS1 and RS2 connected in parallel. The first end of the second diode D1 and the first end of the fifth capacitor C3 are connected to the first end of the second inductor L2. The second end of the second diode D1 and the second end of the fifth capacitor C3 are connected to the cathode of the first diode D2. Specifically, the second diode D1 and the fifth capacitor C3 constitute an input filtering and buffer protection network. The fifth capacitor C3 filters out high-frequency noise at the input terminal, and the second diode D1 provides a freewheeling path for the inductor current. The current feedback resistor network adopts a parallel resistor structure of resistors RS1 and RS2. The current detection threshold can be accurately set by adjusting the parallel resistance value.

[0041] Understandably, this embodiment uses a parallel resistor network for current sampling to improve the accuracy and reliability of current detection; it uses a diode and capacitor combination absorption protection circuit to improve high-frequency noise suppression capability; and it uses a precise current feedback mechanism to improve the system's overcurrent protection response speed.

[0042] Those skilled in the art can make corresponding equivalent improvements based on the application scenario, such as: adjusting the resistance ratio of the current sampling resistor to change the overcurrent protection threshold; or using a different type of fast recovery diode as the second diode; or changing the capacitance value of the fifth capacitor to optimize the high-frequency filtering effect; or using a sampling resistor with a more stable temperature coefficient to improve the detection accuracy.

[0043] Preferred, such as Figure 5As shown in a specific embodiment of this utility model, the BUCK step-down circuit 3 includes an LED constant current driver chip U2, a third inductor L3, and a third diode D3. The LED constant current driver chip U2 is a BP2956. The first input terminal HV pin of the LED constant current driver chip U2 is connected to the output terminal of the active power factor correction boost circuit 2, the second input terminal PWM pin is connected to the output terminal PWM pin of the radar control module 4, and the output terminal DRAIN pin is connected to the first terminal of the third inductor L3 and the anode of the third diode D3. The cathode of the third diode D3 is connected to the output terminal of the active power factor correction boost circuit 2 (the cathode of the first diode D2) and the positive terminal of the LED load. The second terminal of the third inductor L3 is connected to the negative terminal of the LED load. The LED constant current driver chip U2 receives the PWM signal sent by the radar control module 4, adjusts the duty cycle of the internal switching transistor, and controls the energy storage and release process of the third inductor L3, thereby achieving precise adjustment of the output current and ensuring that the LED load obtains a stable and adjustable drive current.

[0044] Understandably, this embodiment improves the output current regulation accuracy by precisely controlling the switch duty cycle through PWM signals; improves the power conversion efficiency through the inductor energy storage and release mechanism; and improves the system's operational reliability by providing a current freewheeling path through the freewheeling diode.

[0045] Those skilled in the art can make corresponding equivalent improvements based on the application scenario, such as: replacing the LED constant current driver chip with other buck controllers with PWM dimming function; or using power inductors of different specifications as the third inductor; or using Schottky diodes of different models as the third diode.

[0046] Preferred, such as Figure 5 As shown in a specific embodiment of this utility model, the BUCK step-down circuit 3 further includes a sixth capacitor EC3, a seventh capacitor C5, a second resistor R9, and a third resistor R10; the sixth capacitor EC3 and the second resistor R9 are connected in parallel between the positive terminal of the third diode D3 and the second terminal of the third inductor L3. The sixth capacitor EC3 is used to filter out high-frequency ripple components in the output current, and the second resistor R9 serves as a dummy load resistor to ensure circuit stability under no-load conditions; the seventh capacitor C5 and the third resistor R10 are connected in parallel between the second input terminal of the LED constant current driver chip U2 and ground. The seventh capacitor C5 is used to filter out high-frequency interference on the PWM signal line, and the third resistor R10 provides a pull-down path for the PWM signal to ensure signal integrity.

[0047] Understandably, this embodiment improves the smoothness of the output current and the stability under no-load conditions by connecting the output filter capacitor in parallel with the load resistor; and improves the signal anti-interference capability and reliability by cooperating with the PWM signal filter capacitor and the pull-down resistor.

[0048] Those skilled in the art can make corresponding equivalent improvements based on the application scenario, such as replacing the electrolytic capacitor with a multilayer ceramic capacitor to reduce the size; or adjusting the resistance value of the dummy load resistor to adapt to different load conditions; or changing the capacitance value of the filter capacitor to optimize the signal filtering effect.

[0049] Preferred, such as Figure 5 As shown in a specific embodiment of this utility model, the BUCK step-down circuit 3 further includes a second current feedback resistor network, a fourth resistor R7, and a fifth resistor R8. The first end of the second current feedback resistor network is connected to the third input terminal of the LED constant current driver chip U2, and the second end is grounded. In this embodiment, the second current feedback resistor network includes resistors RS3 and RS4 connected in parallel. The first input terminal HV pin of the LED constant current driver chip U2 is connected to the output terminal (cathode of the first diode D2) of the active power factor correction boost circuit 2 through the fourth resistor R7. The fourth input terminal ROVP pin of the LED constant current driver chip U2 is grounded through the fifth resistor R8. The second current feedback resistor network accurately detects the output current through the parallel RS3 and RS4 and converts it into a voltage signal to be fed back to the CS pin. The fourth resistor R7 provides current limiting protection for the high voltage input pin. The fifth resistor R8 sets the output voltage protection threshold, which can trigger the overvoltage protection function when the output is open.

[0050] Understandably, this embodiment uses a parallel resistor network for current sampling to improve the detection accuracy and stability of the output current; it uses a current-limiting resistor in series with the high-voltage pin to improve the protection capability of the chip's input terminal; and it uses an output voltage protection resistor to improve the safety and reliability of the circuit when it is open.

[0051] Those skilled in the art can make corresponding equivalent improvements based on the application scenario, such as: adjusting the resistance ratio of the current sampling resistor to change the output current setting; or using current limiting resistors of different power levels as the fourth resistor; or changing the resistance value of the fifth resistor to adjust the overvoltage protection threshold; or using a sampling resistor with a temperature coefficient matching to improve detection accuracy.

[0052] Preferred, such as Figure 7As shown in a specific embodiment of this utility model, the radar sensing LED driving circuit further includes an auxiliary power supply circuit 5. The auxiliary power supply circuit 5 includes a step-down control chip U3, a fourth inductor L4, an eighth capacitor EC4, a ninth capacitor C6, a tenth capacitor EC5, and a sixth resistor R12. The step-down control chip U3 is a BP8501. The first input terminal DRAIN pin of the step-down control chip U3 is connected to the output terminal of the rectifier filter circuit 1 through a diode D4. The second input terminal IC_GND pin is connected to the first terminal of the fourth inductor L4 and the first terminal of the ninth capacitor C6. The third input terminal VCC pin is connected to the second terminal of the ninth capacitor C6. The output terminal VOUT pin is connected to the second terminal of the fourth inductor L4, the first terminal of the tenth capacitor EC5, the first terminal of the sixth resistor R12, and the input terminal VCC pin of the radar control module 4. The first terminal of the eighth capacitor EC4 is connected to the output terminal of the rectifier filter circuit 1 (the second terminal of the first inductor L1), and the second terminal is grounded. The second terminal of the tenth capacitor EC5 and the second terminal of the sixth resistor R12 are grounded. Specifically, the buck control chip U3 adopts a non-isolated buck architecture, directly drawing power from the rectified and filtered DC bus. Through internal switch control and in conjunction with the fourth inductor L4, it converts high-voltage DC into a stable 5-volt DC voltage. The ninth capacitor C6 provides power filtering for the chip, and the tenth capacitor EC5 provides output filtering stability. The sixth resistor R12 acts as a feedback resistor, working with the chip's internal reference voltage to precisely set the output voltage value, ensuring a stable and reliable power supply for the radar control module 4. The SEL pin of the buck control chip U3 is connected to the output voltage feedback network composed of resistors R13 and R14, working with the chip's internal reference voltage to precisely set the output voltage value. Through internal switch control and in conjunction with the fourth inductor L4, it converts high-voltage DC into a stable DC voltage. The ninth capacitor C6 provides power filtering for the chip, and the tenth capacitor EC5 provides output filtering stability, ensuring a stable and reliable power supply for the radar control module 4.

[0053] Understandably, this embodiment directly converts high-voltage DC through a non-isolated buck architecture, improving power conversion efficiency; sets the output voltage through a precision feedback resistor network, improving voltage output accuracy; improves power quality stability through a multi-stage capacitor filtering design; and improves circuit space utilization through an integrated design scheme.

[0054] Those skilled in the art can make corresponding equivalent improvements based on the application scenario, such as: replacing the buck control chip with other types of non-isolated buck chips; or adjusting the resistance value of the sixth resistor to change the output voltage value; or using inductors of different specifications as the fourth inductor to optimize conversion efficiency; or increasing the output capacitor capacity to enhance the load transient response capability.

[0055] Compared with the prior art, the beneficial effects of this utility model include at least the following: This invention proposes a radar-sensing LED driving circuit that improves the efficiency of power grid utilization and reduces harmonic pollution through active power factor correction technology; improves the accuracy and stability of output current control through BUCK buck topology combined with PWM dimming technology; achieves intelligent segmented adjustment of lighting brightness through coordinated control of radar sensing and ambient light perception; and significantly reduces the size of the driving circuit and lowers system cost while meeting high power factor requirements through multi-level circuit collaborative operation.

[0056] Furthermore, this utility model also improves EMI performance by suppressing electromagnetic interference through common-mode inductors; enhances surge current suppression by forming an active damping circuit using inductors and resistors in parallel; improves power quality stability by smoothing DC waveforms through a π-type filter network; enhances overcurrent protection reliability through series fuse protection; improves differential-mode interference suppression by parallel filtering with safety capacitors; enhances lightning surge protection level through parallel protection with varistors; improves power factor and energy utilization efficiency by shaping current waveforms through an active power factor correction control chip; improves boost conversion efficiency by achieving energy conversion through the coordinated work of inductors and switching elements; improves the stability and reliability of DC output voltage through output capacitor filtering and voltage regulation; improves circuit startup reliability by providing initial operating voltage through a startup resistor network; improves voltage regulation control accuracy by accurately sampling output voltage through a voltage feedback network; improves chip operating stability by optimizing power supply quality through a VCC pin filter capacitor; improves current detection accuracy and reliability by accurately sampling switching current through a current feedback resistor network; and improves current detection accuracy and reliability through diodes and... The capacitor combination absorbs high-frequency noise, improving electromagnetic compatibility performance; the LED constant current driver chip receives PWM signals to precisely adjust the duty cycle, improving output current control accuracy and dimming light performance; a step-down inductor achieves efficient energy conversion, improving overall system efficiency; a freewheeling diode provides a current loop, improving circuit stability and reliability; a parallel RC network at the output end filters high-frequency ripple, improving LED load current stability; a parallel RC filter network at the PWM signal end suppresses interference, improving dimming signal noise immunity and reliability; a second current feedback resistor network precisely samples the output current, improving constant current control accuracy; a fourth resistor limits high-voltage input current, improving chip input protection capability; a fifth resistor sets the overvoltage protection threshold, improving safety when the output is open-circuited; a non-isolated step-down architecture directly converts high-voltage DC, improving power conversion efficiency; inductor and capacitor synergistic filtering improves output voltage stability; feedback resistors precisely set voltage values, improving output accuracy; and a multi-stage capacitor filtering design improves power supply anti-interference capability.

[0057] In summary, this invention solves the technical problems of existing radar LED lights, such as single dimming mode, low power factor, and low efficiency.

[0058] The above description is only a preferred embodiment of the present utility model and does not limit the patent scope of the present utility model. All equivalent structural transformations made under the inventive concept of the present utility model using the contents of the present utility model specification and drawings, or direct / indirect applications in other related technical fields, are included within the patent protection scope of the present utility model.

Claims

1. A radar-sensing LED driving circuit, characterized in that, include: The rectifier and filter circuit (1) has an input terminal connected to AC mains power and is used to rectify and filter AC power into DC power. An active power factor correction boost circuit (2) has its input terminal connected to the output terminal of the rectifier filter circuit (1) to improve the power factor and output a stable high voltage. The BUCK step-down circuit (3) has its input terminal connected to the output terminal of the active power factor correction boost circuit (2), and its output terminal is used to connect to the LED load. The BUCK step-down circuit (3) has a PWM signal input terminal, which is used to receive PWM signals to regulate the current output to the LED load. The radar control module (4) has its input end connected to the output end of the rectifier filter circuit (1) and its output end connected to the PWM signal input end of the BUCK step-down circuit (3). The radar control module (4) is used to sense the ambient illuminance and lock the corresponding PWM signal parameters, and to trigger the output of the locked PWM signal when human movement is sensed.

2. The radar-sensing LED driving circuit as described in claim 1, characterized in that, The rectifier-filter circuit (1) includes a first inductor, a first resistor, a first capacitor, a second capacitor, a common-mode inductor, and a rectifier bridge; the input terminal of the common-mode inductor is connected to AC mains power, and the output terminal is connected to the AC input terminal of the rectifier bridge; the DC output terminal of the rectifier bridge is connected to the first terminal of the first inductor, the first terminal of the first resistor, and the first terminal of the first capacitor; the second terminal of the first inductor is connected to the second terminal of the first resistor and the first terminal of the second capacitor, and the second terminal of the first capacitor and the second terminal of the second capacitor are grounded.

3. The radar-sensing LED driving circuit as described in claim 2, characterized in that, The rectifier and filter circuit (1) also includes a fuse, a safety capacitor and a varistor; the fuse is connected in series between the mains live wire L and the input terminal of the common mode inductor; the safety capacitor is connected in parallel between the mains live wire L and the neutral wire N; the varistor is connected in parallel between the two output terminals of the common mode inductor.

4. The radar-sensing LED driving circuit as described in claim 1, characterized in that, The active power factor correction boost circuit (2) includes an active power factor correction control chip, a second inductor, a first diode, and a third capacitor; the first end of the second inductor is connected to the output end of the rectifier filter circuit (1), and the second end is connected to the output end of the active power factor correction control chip; the first input end of the active power factor correction control chip is connected to the output end of the rectifier filter circuit (1); the anode of the first diode is connected to the second end of the second inductor, and the cathode is connected to the first end of the third capacitor and serves as the output end of the active power factor correction boost circuit (2); the second end of the third capacitor is grounded.

5. The radar-sensing LED driving circuit as described in claim 4, characterized in that, The active power factor correction boost circuit (2) further includes a startup resistor network, a voltage feedback resistor network, and a fourth capacitor; the first end of the startup resistor network is connected to the output end of the rectifier filter circuit (1), the second end is connected to the first input end of the active power factor correction control chip and the first end of the fourth capacitor, and the second end of the fourth capacitor is grounded; the first end of the voltage feedback resistor network is connected to the cathode of the first diode, and the second end is grounded; the second input end of the active power factor correction control chip is connected to the sampling node of the voltage feedback resistor network.

6. The radar-sensing LED driving circuit as described in claim 5, characterized in that, The active power factor correction boost circuit (2) further includes a current feedback resistor network, a second diode, and a fifth capacitor; the current feedback resistor network is connected between the third input terminal of the active power factor correction control chip and ground; the first end of the second diode and the first end of the fifth capacitor are connected to the first end of the second inductor; the second end of the second diode and the second end of the fifth capacitor are connected to the cathode of the first diode.

7. The radar-sensing LED driving circuit as described in claim 1, characterized in that, The BUCK step-down circuit (3) includes an LED constant current driver chip, a third inductor, and a third diode; the first input terminal of the LED constant current driver chip is connected to the output terminal of the active power factor correction boost circuit (2), the second input terminal is connected to the output terminal of the radar control module (4), and the output terminal is connected to the first terminal of the third inductor and the anode of the third diode; the cathode of the third diode is connected to the output terminal of the active power factor correction boost circuit (2) and the positive terminal of the LED load; the second terminal of the third inductor is connected to the negative terminal of the LED load.

8. The radar-sensing LED driving circuit as described in claim 7, characterized in that, The BUCK step-down circuit (3) further includes a sixth capacitor, a seventh capacitor, a second resistor, and a third resistor; the sixth capacitor and the second resistor are connected in parallel between the positive terminal of the third diode and the second terminal of the third inductor; the seventh capacitor and the third resistor are connected in parallel between the second input terminal of the LED constant current driver chip and ground.

9. The radar-sensing LED driving circuit as described in claim 7, characterized in that, The BUCK step-down circuit (3) further includes a second current feedback resistor network, a fourth resistor, and a fifth resistor; the first end of the second current feedback resistor network is connected to the third input terminal of the LED constant current driver chip, and the second end is grounded; the first input terminal of the LED constant current driver chip is connected to the output terminal of the active power factor correction boost circuit (2) through the fourth resistor; The fourth input terminal of the LED constant current driver chip is grounded through the fifth resistor.

10. The radar-sensing LED driving circuit according to any one of claims 1 to 9, characterized in that, It also includes an auxiliary power supply circuit (5), which includes a step-down control chip, a fourth inductor, an eighth capacitor, a ninth capacitor, a tenth capacitor, and a sixth resistor; the first input terminal of the step-down control chip is connected to the output terminal of the rectifier filter circuit (1), the second input terminal is connected to the first terminal of the fourth inductor and the first terminal of the ninth capacitor, the third input terminal is connected to the second terminal of the ninth capacitor, and the output terminal is connected to the second terminal of the fourth inductor, the first terminal of the tenth capacitor, the first terminal of the sixth resistor, and the input terminal of the radar control module (4); the first terminal of the eighth capacitor is connected to the output terminal of the rectifier filter circuit (1), and the second terminal is grounded; the second terminal of the tenth capacitor and the second terminal of the sixth resistor are grounded.

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