LED drive control circuit with ultrasonic dynamic dimming function and implementation method of LED drive control circuit

Abstract

A microprocessor comprises a main control chip, a PWM2 pin of the main control chip is connected with an optocoupler isolation circuit, the optocoupler isolation circuit is connected with an LED constant-current dimming drive circuit, the LED constant-current dimming drive circuit is connected with an LED light source, a PWM1 pin and a DAC pin of the main control chip are both connected with an ultrasonic transmitting circuit, and the ultrasonic transmitting circuit is connected with an LED light source. The ultrasonic transmitting circuit is connected with the ultrasonic receiving circuit through the ultrasonic transmitting and receiving probe, and the ultrasonic receiving circuit is connected with an ADC pin of the main control chip through the signal processing circuit; the invention further discloses an implementation method of the LED drive control circuit with the ultrasonic dynamic dimming function. According to the invention, natural brightness adjustment of near-dark and far-bright is realized through ultrasonic real-time distance measurement in combination with a self-adaptive dimming algorithm, intelligent dynamic dimming is realized, a user does not need to perform manual operation, the illumination brightness dynamically changes along with the distance, visual fatigue caused by too strong or too dark light is avoided, and the interaction comfort is remarkably improved.

Description

Technical Field

[0001] This invention belongs to the field of dynamic dimming technology, specifically relating to an ultrasonic dynamic dimming LED driving control circuit and its implementation method. Background Technology

[0002] With the rapid development of LED lighting and driver technology, consumers are increasingly demanding higher levels of intelligence and energy efficiency from lighting equipment. Currently, the main intelligent dimming technologies on the market include the following solutions, but they still have significant limitations:

[0003] 1. Manual or remote dimming technology: These technologies commonly use integrated Wi-Fi, Bluetooth, or ZigBee modules to support manual brightness adjustment via mobile app or voice control. However, they require active user operation and cannot dynamically adjust based on human position, leading to energy waste (studies show that approximately 25%-35% of the electricity used in household lighting is wasted because the lights are not dimmed promptly after the user leaves).

[0004] 2. Photosensitive ambient adaptive dimming technology: This technology detects ambient light intensity using a photosensitive sensor and automatically switches between day and night modes. However, it only responds to changes in ambient light and cannot sense the user's distance, leading to misalignment issues such as "lights on when people leave" or "lights off when people are near".

[0005] 3. Infrared or ultrasonic human body sensing technology: Infrared pyroelectric (PIR) or ultrasonic sensors are used to trigger light switches. However, infrared sensors cannot measure distance and are susceptible to temperature interference. Furthermore, existing ultrasonic solutions only support switch control and lack continuous dimming functionality, resulting in a clunky user experience. Summary of the Invention

[0006] The purpose of this invention is to provide an ultrasonic dynamic dimming LED driver control circuit to solve the problems mentioned in the background art. The ultrasonic dynamic dimming LED driver control circuit provided by this invention features that the user does not need to manually operate it, the illumination brightness dynamically changes with distance, and it avoids visual fatigue caused by excessively strong or dim light.

[0007] Another objective of this invention is to provide a method for implementing an ultrasonic dynamic dimming LED driving control circuit.

[0008] To achieve the above objectives, the present invention provides the following technical solution: an ultrasonic dynamic dimming LED driving control circuit, comprising a microprocessor, an optocoupler isolation circuit, an LED light source, an LED constant current dimming driving circuit, an isolated DC source, an ultrasonic receiving circuit, an ultrasonic transmitting circuit, and a signal processing circuit. The LED constant current dimming driving circuit and the isolated DC source are respectively connected to 220VAC mains power. The isolated DC source is connected to the microprocessor, the optocoupler isolation circuit, the ultrasonic receiving circuit, and the ultrasonic transmitting circuit. The microprocessor includes a main control chip. The PWM2 pin of the main control chip is connected to the optocoupler isolation circuit, which is connected to the LED constant current dimming driving circuit. The LED constant current dimming driving circuit is connected to the LED light source. The PWM1 pin and DAC pin of the main control chip are both connected to the ultrasonic transmitting circuit. The ultrasonic transmitting circuit is connected to the ultrasonic receiving circuit via ultrasonic transmitting and receiving probes. The ultrasonic receiving circuit is connected to the ADC pin of the main control chip via the signal processing circuit.

[0009] In this invention, the LED constant current dimming drive circuit further includes a rectifier bridge DB1 and a chip U7. Pin 1 of the rectifier bridge DB1 is connected to the neutral line N, pin 2 of the rectifier bridge DB1 is connected to the live line L, pin 3 of the rectifier bridge DB1 is connected to pin 8 of the chip U1, the negative terminal of the freewheeling diode D7, one end of the electrolytic capacitor CE1, and the positive terminal of the LED light source. Pins 5 and 6 of the chip U7 are connected to the positive terminal of the freewheeling diode D7 and one end of the power inductor L2, respectively. The other end of the power inductor L2 is connected to the other end of the electrolytic capacitor CE1 and the negative terminal of the LED light source, respectively. Pin 1 of the chip U7 is connected to a resistor R19, and the other end of the resistor R19 and pin 4 of the rectifier bridge DB1 are both connected to the ground terminal. Pin 2 of the chip U7 is connected to an optocoupler isolation circuit.

[0010] In this invention, the optocoupler isolation circuit further includes an optocoupler U8. Pin 1 of the optocoupler U8 is connected to a 3.3V DC constant voltage power supply. Pin 2 of the optocoupler U8 is connected to the collector of transistor Q1. The base of transistor Q1 is connected to one end of resistors R11 and R13 respectively. The other end of resistor R11 is connected to the microprocessor. The emitter of transistor Q1 and the other end of resistor R13 are connected to signal ground respectively. Pin 4 of the optocoupler U8 is connected to a 5V DC constant voltage power supply. Pin 3 of the optocoupler U8 is connected to one end of resistors R17 and R18 respectively. The other end of resistor R17 is connected to one end of capacitor C9 and the LED constant current dimming drive circuit respectively. The other ends of resistor R18 and capacitor C9 are connected to the ground terminal respectively.

[0011] In this invention, the ultrasonic receiving circuit further includes an amplifier U3. The output terminal of the amplifier U3 is connected to one end of the output coupling capacitor C3 and the feedback resistor R5, respectively. The other end of the output coupling capacitor C3 is connected to the signal processing circuit. The other end of the feedback resistor R5 and the negative input terminal of the amplifier U3 are connected to one end of the resistor R10, respectively. The positive input terminal of the amplifier U3 is connected to a 1.25V DC reference voltage, a resistor R6, and one end of the capacitor C4, respectively. The other end of the capacitor C4 is connected to one end of the resistor R7, the positive terminal of the diode D1, the negative terminal of the diode D2, and pin 1 of the ultrasonic receiving probe TR1, respectively. Pin 2 of the ultrasonic receiving probe TR1, the positive terminal of the diode D2, the negative terminal of the diode D1, and the other ends of resistors R7, R6, and R10 are all connected to the signal ground.

[0012] In this invention, the signal processing circuit further includes a bandpass filter operation chip U2. The positive input terminal of the bandpass filter operation chip U2 is connected to one end of resistor R9 and capacitor C2, respectively. The other end of capacitor C2 is connected to one end of resistor R1, resistor R2 and capacitor C5, respectively. The other end of resistor R2 is connected to the ultrasonic receiving circuit. The output terminal of the bandpass filter operation chip U2 is connected to the other end of resistor R1, capacitor C1 and one end of resistor R4, respectively. The other end of resistor R4 and the negative input terminal of the bandpass filter operation chip U2 are connected to one end of resistor R8, respectively. The other end of capacitor C1 is connected to pin 3 of instrumentation amplifier U1. Resistor R3 is connected in parallel to pins 1 and 8 of instrumentation amplifier U1. Pin 6 of instrumentation amplifier U1 is connected to the microprocessor. Pin 2 of instrumentation amplifier U1, the other end of resistor R8, resistor R9 and capacitor C5 are connected to signal ground, respectively.

[0013] In this invention, the ultrasonic transmitting circuit further includes a frequency amplitude superposition circuit, a push-pull amplification circuit, and a transformer drive switch circuit connected in sequence.

[0014] In this invention, the frequency amplitude superposition circuit further includes an amplifier U5 and an arithmetic unit U6. The positive input terminal of the amplifier U5 is connected to the microprocessor, and the negative input terminal of the amplifier U5 is connected to one end of resistors R14 and R15, respectively. The positive input terminal of the arithmetic unit U6 is connected to the microprocessor, and the negative input terminal and the output terminal of the arithmetic unit U6 are both connected to one end of the coupling capacitor C7. The other end of resistor R15 and the output terminal of amplifier U5 are connected to the base of transistor Q2, respectively. The other end of coupling capacitor C7 is connected to the emitter of transistor Q2 and one end of coupling capacitor C8, respectively. The collector of transistor Q2 is connected to a +15V DC constant voltage power supply, and the other end of coupling capacitor C8 is connected to a push-pull amplifier circuit.

[0015] In this invention, the push-pull amplifier circuit further includes transistors Q3 and Q5. The collector of transistor Q3 is connected to one end of resistor R12 and a +15V DC constant voltage power supply. The other end of resistor R12 and the base of transistor Q3 are connected to the positive terminal of clamping diode D3. The negative terminal of clamping diode D3 is connected to the positive terminal of clamping diode D4. The negative terminal of clamping diode D4 is connected to the other end of capacitor C8, one end of resistor R16, and the base of transistor Q5. The other end of resistor R16 and the collector of transistor Q5 are both connected to a -15V DC constant voltage power supply. The emitters of transistors Q3 and Q5 are connected to a transformer drive switching circuit.

[0016] In this invention, the transformer drive switching circuit further includes a MOSFET Q4, the gate of which is connected to the emitters of transistors Q3 and Q5, respectively, and the drain of which is connected to one end of inductor L1 and capacitor C6, respectively. The other end of inductor L1 is connected to a +15V DC constant voltage power supply, and the other end of capacitor C6 is connected to one end of the primary coil of transformer T1. The secondary coil of transformer T1 is connected in parallel with ultrasonic transmitting probe TR2, and the other end of resistor R14 and the other end of the primary coil of transformer T1 are both connected to signal ground.

[0017] Furthermore, in this invention, the method for implementing an ultrasonic dynamic dimming LED driving control circuit includes the following steps:

[0018] (i) The main control chip is responsible for outputting the dimming control signal PWM2, the ultrasonic transmission frequency control signal PWM1 and the ultrasonic transmission amplitude control signal DAC, and at the same time performs AD sampling on the echo signal after ultrasonic reception and processing.

[0019] (ii) The optocoupler isolation circuit realizes the opto-isolated transmission of the dimming control signal PWM2 of the low-voltage main control section and the PWM dimming input signal of the LED constant current dimming drive circuit of the high-voltage section.

[0020] (III) The LED constant current dimming drive circuit realizes the dimming current control of the LED light source;

[0021] (iv) The ultrasonic transmitting probe is used to transmit ultrasonic signals, and the ultrasonic receiving probe is used to receive echo signals.

[0022] (V) The ultrasonic transmitting circuit superimposes the ultrasonic transmission amplitude signal and frequency signal to enhance the driving capability of the ultrasonic carrier control signal and realize the driving of the primary coil of the ultrasonic transmitting probe driving transformer.

[0023] (vi) The signal processing circuit amplifies and filters the echo signal received by the ultrasonic receiving probe, and the main control chip performs AD sampling analysis.

[0024] Compared with the prior art, the beneficial effects of the present invention are:

[0025] 1. This invention achieves natural brightness adjustment of "near dark and far bright" by using real-time ultrasonic ranging combined with an adaptive dimming algorithm. It realizes intelligent dynamic dimming, and users do not need to operate manually. The lighting brightness changes dynamically with distance, avoiding visual fatigue caused by excessively strong or dim light, and significantly improving the comfort of interaction.

[0026] 2. This invention is highly efficient and energy-saving, reducing ineffective energy consumption. When the user leaves the detection area, the system automatically dims or turns off the lights, and brightens them as needed when the user approaches. Actual tests show that compared with the traditional fixed brightness mode, it can reduce ineffective energy consumption by 30%-50%, which is in line with the development trend of green lighting.

[0027] 3. This invention has high anti-interference capability and system stability. It adopts bidirectional signal processing technology. The transmitting end optimizes energy transmission through push-pull drive and transformer boost, while the receiving end integrates bandpass filter and differential amplifier circuit to effectively suppress environmental noise. In addition, the system has a false trigger rate of less than 2% in complex home environments, and its reliability is significantly better than traditional infrared solutions. Attached Figure Description

[0028] Figure 1 This is a schematic diagram of the principle of the present invention.

[0029] Figure 2 This is a circuit diagram of the optocoupler isolation circuit of the present invention.

[0030] Figure 3 This is a circuit diagram showing the connection between the LED constant current dimming drive circuit of the present invention and the 220VAC mains power supply and the LED light source.

[0031] Figure 4 This is a circuit diagram of the ultrasonic receiving circuit and signal processing circuit of the present invention.

[0032] Figure 5 This is a circuit diagram of the ultrasonic transmitting circuit of the present invention.

[0033] In the diagram: 1. Microprocessor; 2. Optocoupler isolation circuit; 3. LED light source; 4. LED constant current dimming drive circuit; 5. 220VAC mains power; 6. Isolated DC power source; 7. Ultrasonic transmitting circuit; 8. Ultrasonic transmitting and receiving probe; 9. Ultrasonic receiving circuit; 10. Signal processing circuit. Detailed Implementation

[0034] The technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0035] Example 1

[0036] Please see Figures 1-5 The present invention provides the following technical solution: an ultrasonic dynamic dimming LED driving control circuit, comprising a microprocessor, an optocoupler isolation circuit, an LED light source, an LED constant current dimming driving circuit, an isolated DC source, an ultrasonic receiving circuit, an ultrasonic transmitting circuit, and a signal processing circuit. The LED constant current dimming driving circuit and the isolated DC source are respectively connected to 220VAC mains power. The isolated DC source is connected to the microprocessor, the optocoupler isolation circuit, the ultrasonic receiving circuit, and the ultrasonic transmitting circuit. The microprocessor includes a main control chip, which is STMicroelectronics' STM32F103C8T6 chip. The PWM2 pin of the main control chip is connected to the optocoupler isolation circuit, which is connected to the LED constant current dimming driving circuit. The LED constant current dimming driving circuit is connected to the LED light source. The PWM1 pin and DAC pin of the main control chip are both connected to the ultrasonic transmitting circuit. The ultrasonic transmitting circuit is connected to the ultrasonic receiving circuit via ultrasonic transmitting and receiving probes. The ultrasonic receiving circuit is connected to the ADC pin of the main control chip via the signal processing circuit.

[0037] By adopting the above technical solution, this invention achieves natural brightness adjustment of "darker near, brighter far" through real-time ultrasonic ranging combined with an adaptive dimming algorithm (provided by the main control chip). This intelligent dynamic dimming eliminates the need for manual operation, as the lighting brightness dynamically changes with distance, avoiding visual fatigue caused by excessively strong or dim light and significantly improving interactive comfort. This invention is highly energy-efficient, reducing ineffective energy consumption. When the user leaves the detection area, the system automatically dims or turns off the light, and brightens it as needed when the user approaches. Actual measurements show that compared to traditional fixed brightness modes, it can reduce ineffective energy consumption by 30%-50%, aligning with the trend of green lighting development. This invention features high anti-interference capability and system stability. It employs bidirectional signal processing technology; the transmitter optimizes energy transmission through push-pull drive and transformer boost, while the receiver integrates bandpass filtering and differential amplification circuits to effectively suppress environmental noise (such as electrical interference and multipath reflection). Furthermore, the system's false trigger rate is less than 2% in complex home environments, demonstrating significantly better reliability than traditional infrared solutions.

[0038] Specifically, the LED constant current dimming drive circuit includes a rectifier bridge DB1 and a chip U7. Pin 1 of the rectifier bridge DB1 is connected to the neutral line N, pin 2 of the rectifier bridge DB1 is connected to the live line L, pin 3 of the rectifier bridge DB1 is connected to pin 8 of the chip U1, the negative terminal of the freewheeling diode D7, one end of the electrolytic capacitor CE1, and the positive terminal of the LED light source. Pins 5 and 6 of the chip U7 are connected to the positive terminal of the freewheeling diode D7 and one end of the power inductor L2, respectively. The other end of the power inductor L2 is connected to the other end of the electrolytic capacitor CE1 and the negative terminal of the LED light source, respectively. Pin 1 of the chip U7 is connected to a resistor R19, and the other end of the resistor R19 and pin 4 of the rectifier bridge DB1 are both connected to the ground terminal. Pin 2 of the chip U7 is connected to the optocoupler isolation circuit.

[0039] By adopting the above technical solution, the LED constant current dimming drive circuit uses the KP14153SGA step-down LED constant current dimming drive chip from Shenzhen Biyi Microelectronics as the core to realize the dimming current control of the LED light source.

[0040] Specifically, the optocoupler isolation circuit includes optocoupler U8. Pin 1 of optocoupler U8 is connected to a 3.3V DC constant voltage power supply. Pin 2 of optocoupler U8 is connected to the collector of transistor Q1. The base of transistor Q1 is connected to one end of resistors R11 and R13 respectively. The other end of resistor R11 is connected to the microprocessor. The emitter of transistor Q1 and the other end of resistor R13 are connected to signal ground respectively. Pin 4 of optocoupler U8 is connected to a 5V DC constant voltage power supply. Pin 3 of optocoupler U8 is connected to one end of resistors R17 and R18 respectively. The other end of resistor R17 is connected to one end of capacitor C9 and the LED constant current dimming driver circuit respectively. The other ends of resistor R18 and capacitor C9 are connected to the ground terminal respectively.

[0041] By adopting the above technical solution, the optocoupler isolation circuit uses the PC817A optocoupler isolation chip from Autosemi Technology Co., Ltd. as the core circuit to realize the optocoupler isolation transmission of the dimming control signal PWM2 of the low-voltage main control section and the PWM dimming input signal of the LED constant current dimming drive circuit of the high-voltage section.

[0042] Specifically, the ultrasonic receiving circuit includes amplifier U3. The output terminal of amplifier U3 is connected to one end of output coupling capacitor C3 and feedback resistor R5. The other end of output coupling capacitor C3 is connected to the signal processing circuit. The other end of feedback resistor R5 and the negative input terminal of amplifier U3 are connected to one end of resistor R10. The positive input terminal of amplifier U3 is connected to a 1.25V DC reference voltage, resistor R6, and one end of capacitor C4. The other end of capacitor C4 is connected to one end of resistor R7, the positive terminal of diode D1, the negative terminal of diode D2, and pin 1 of ultrasonic receiving probe TR1. Pin 2 of ultrasonic receiving probe TR1, the positive terminal of diode D2, the negative terminal of diode D1, and the other ends of resistors R7, R6, and R10 are all connected to signal ground.

[0043] The above technical solution is used to receive ultrasonic echo signals and provide them to the signal processing circuit.

[0044] Specifically, the signal processing circuit includes a bandpass filter operational chip U2. The positive input terminal of the bandpass filter operational chip U2 is connected to one end of resistor R9 and capacitor C2, respectively. The other end of capacitor C2 is connected to one end of resistor R1, resistor R2 and capacitor C5, respectively. The other end of resistor R2 is connected to the ultrasonic receiving circuit. The output terminal of the bandpass filter operational chip U2 is connected to the other end of resistor R1, capacitor C1 and one end of resistor R4, respectively. The other end of resistor R4 and the negative input terminal of the bandpass filter operational chip U2 are connected to one end of resistor R8, respectively. The other end of capacitor C1 is connected to pin 3 of instrumentation amplifier U1. Resistor R3 is connected in parallel to pins 1 and 8 of instrumentation amplifier U1. Pin 6 of instrumentation amplifier U1 is connected to the microprocessor. Pin 2 of instrumentation amplifier U1, the other end of resistor R8, resistor R9 and capacitor C5 are connected to signal ground, respectively.

[0045] By adopting the above technical solution, the signal processing circuit consists of an RC passive high-pass filter, a non-inverting amplifier, an active band-pass filter, and an instrumentation amplifier. The non-inverting amplifier and band-pass filter use the Analog Devices, Inc. LTC2058IS8E precision operational amplifier as the core, and the instrumentation amplifier uses the AD8610ARZ FET operational amplifier as the core to amplify and filter the echo signal received by the ultrasonic receiving probe.

[0046] The working principle of this invention is as follows:

[0047] The main control chip outputs a dimming signal PWM2. During the transition from low to high level of PWM, the transmitter of optocoupler U8 switches from cutoff to conduction, and simultaneously the receiver switches from cutoff to conduction. The dimming control pin of the LED dimming core chip switches from the default low level to high level, and the LED constant current drive circuit starts to build up output, forming an output current. The output dimming signal PWM2 remains at a high level, and the LED constant current drive circuit maintains maximum current output. At the same time, the main control chip starts to output the ultrasonic transmission amplitude signal DAC and the ultrasonic transmission frequency signal PWM1. The DAC signal is output after passing through amplifier U5 and then fed to the core of the signal superposition circuit. Transistor Q2 provides the base bias voltage, controlling its quiescent operating point. The PWM1 signal, after passing through the arithmetic unit U6, is output to the input coupling capacitor C6 of the superposition circuit to filter out the DC component, transmitting only the high-frequency AC component. This signal is then input to the emitter of transistor Q2. Transistor Q2 in the superposition circuit acts as a common-emitter amplifier, superimposing and mixing the amplitude and frequency signals to output an ultrasonic carrier drive signal with frequency PWM1. This ultrasonic carrier drive signal is input to the transmitter complementary push-pull drive circuit through coupling capacitor C8, and then passes through a push-pull amplifier composed of NPN and PNP transistors to increase the driving power of the carrier drive signal. When the input signal (coupling capacitor C8 terminal) is high, transistor Q3 conducts, and current flows from VCC2 through transistor Q3 to the load. When the input signal is low, transistor Q5 conducts, and current flows from the load through transistor Q5 to ground. The carrier drive signal is drawn from power supplies VCC2 and VSS, enhancing the driving capability of the drive signal, and then input to the gate of MOSFET Q4 in the ultrasonic transformer drive switching circuit. When the carrier drive signal is high, MOSFET Q4 conducts, driving power supply VCC3 to charge the energy storage inductor of the switching circuit, and simultaneously storing energy in the primary coil of the transformer. When the wave drive signal is low, MOSFET Q4 is turned off. The energy in the energy storage inductor is superimposed on the primary coil of the transformer through the coupling capacitor, and then discharged through the secondary coil of the transformer to drive the ultrasonic transmitting probe to emit an ultrasonic signal. After the ultrasonic signal is reflected by a moving human body, the echo signal is received by the ultrasonic receiving probe, causing a change in charge distribution within the probe material, forming a micro-AC voltage signal proportional to the vibration amplitude. The echo signal then undergoes initial filtering processing by a first-order passive RC high-pass filter. Capacitor C4 and resistor R7 form the high-pass filter, with a cutoff frequency of f. H The cutoff frequency formula is as follows:

[0048]

[0049] Where the cutoff frequency is f HThe frequency needs to be lower than that of the ultrasound probe. After passive filtering, the ultrasound signal is then amplified by an in-phase amplifier. A VREF voltage is superimposed at the non-inverting input of the in-phase amplifier as a reference bias. The input of the in-phase amplifier is U... in The output is U out1 The gain function of this in-phase amplifier is as follows:

[0050]

[0051] Its magnification is determined by R5 and R 10 The ultrasonic echo signal, after being amplified in phase for the first stage, will then undergo a second-stage filtering process using a second-order voltage-controlled voltage source bandpass filter with U2 as its core. The target parameter of the second-order voltage-controlled voltage source bandpass filter is the center frequency f0, as shown in the following formula:

[0052]

[0053] Gain A formula:

[0054]

[0055] Bandwidth (BW) formula:

[0056]

[0057] The Laplace transform transfer function of the second-order voltage-controlled voltage source bandpass filter is as follows:

[0058]

[0059] Its center frequency f0 is the ultrasonic frequency. A narrow bandwidth (high Q value) can be achieved by adjusting R1 >> R2 and C5 >> C9, while its gain A is controlled by R4 and R8. After passing through a second-order voltage-controlled voltage source bandpass filter, it enters the instrumentation amplifier for secondary amplification. Finally, the echo signal is acquired by the ADC_IN pin of the MCU.

[0060] This invention adds an ultrasonic transmitting circuit, an ultrasonic receiving circuit, an optocoupler isolation circuit, and a microprocessor to the LED constant current dimming drive circuit. The microprocessor analyzes the real-time distance between the human body and the LED light source based on the collected echo signal and adjusts the duty cycle of the output dimming PWM2 signal in real time. When the detected target is close to the light source, the main control chip controls the low level ratio of the PWM2 output signal to increase, the LED constant current drive current to decrease, and the LED light source brightness to decrease. When the detected target is far from the light source, the main control chip controls the high level ratio of the PWM2 output signal to increase, the LED constant current drive current to increase, and the LED light source brightness to increase.

[0061] In this invention, the ultrasonic transmitting probe and ultrasonic receiving probe adopt a piezoelectric ceramic ultrasonic transducer. Its key parameters are a transmitting drive frequency of 1MHz, an echo detection distance of 3 to 6 meters, and an echo detection radius of 3 to 6 meters.

[0062] Example 2

[0063] The difference between this embodiment and Embodiment 1 is that, specifically, the ultrasonic transmitting circuit includes a frequency amplitude superposition circuit, a push-pull amplifier circuit, and a transformer drive switch circuit connected in sequence. The frequency amplitude superposition circuit includes amplifier U5 and arithmetic unit U6. The positive input terminal of amplifier U5 is connected to the microprocessor, and the negative input terminal of amplifier U5 is connected to one end of resistors R14 and R15 respectively. The positive input terminal of arithmetic unit U6 is connected to the microprocessor, and both the negative input terminal and the output terminal of arithmetic unit U6 are connected to one end of coupling capacitor C7. The other end of resistor R15 and the output terminal of amplifier U5 are connected to the base of transistor Q2 respectively. The other end of coupling capacitor C7 is connected to the emitter of transistor Q2 and one end of coupling capacitor C8 respectively. The collector of transistor Q2 is connected to a +15V DC constant voltage power supply, and the other end of coupling capacitor C8 is connected to the push-pull amplifier circuit.

[0064] By adopting the above technical solution, the ultrasonic emission amplitude signal and frequency signal are superimposed.

[0065] Specifically, the push-pull amplifier circuit includes transistors Q3 and Q5. The collector of transistor Q3 is connected to one end of resistor R12 and a +15V DC constant voltage power supply. The other end of resistor R12 and the base of transistor Q3 are connected to the positive terminal of clamping diode D3. The negative terminal of clamping diode D3 is connected to the positive terminal of clamping diode D4. The negative terminal of clamping diode D4 is connected to the other end of capacitor C8, one end of resistor R16, and the base of transistor Q5. The other end of resistor R16 and the collector of transistor Q5 are both connected to a -15V DC constant voltage power supply. The emitters of transistors Q3 and Q5 are connected to the transformer drive switching circuit.

[0066] By adopting the above technical solution, the driving capability of the ultrasonic carrier control signal is enhanced.

[0067] Specifically, the transformer-driven switching circuit includes a MOSFET Q4. The gate of MOSFET Q4 is connected to the emitters of transistors Q3 and Q5, respectively. The drain of MOSFET Q4 is connected to one end of inductor L1 and capacitor C6, respectively. The other end of inductor L1 is connected to a +15V DC constant voltage power supply. The other end of capacitor C6 is connected to one end of the primary coil of transformer T1. The secondary coil of transformer T1 is connected in parallel with the ultrasonic transmitting probe TR2. The other end of resistor R14 and the other end of the primary coil of transformer T1 are both connected to signal ground.

[0068] By adopting the above technical solution, the primary coil of the ultrasonic transmitting probe driving transformer can be driven.

[0069] Example 3

[0070] Furthermore, the implementation method of the ultrasonic dynamic dimming LED driving control circuit of the present invention includes the following steps:

[0071] (i) The main control chip is responsible for outputting the dimming control signal PWM2, the ultrasonic transmission frequency control signal PWM1 and the ultrasonic transmission amplitude control signal DAC, and at the same time performs AD sampling on the echo signal after ultrasonic reception and processing.

[0072] (ii) The optocoupler isolation circuit realizes the opto-isolated transmission of the dimming control signal PWM2 of the low-voltage main control section and the PWM dimming input signal of the LED constant current dimming drive circuit of the high-voltage section.

[0073] (III) The LED constant current dimming drive circuit realizes the dimming current control of the LED light source;

[0074] (iv) The ultrasonic transmitting probe is used to transmit ultrasonic signals, and the ultrasonic receiving probe is used to receive echo signals.

[0075] (V) The ultrasonic transmitting circuit superimposes the ultrasonic transmission amplitude signal and frequency signal to enhance the driving capability of the ultrasonic carrier control signal and realize the driving of the primary coil of the ultrasonic transmitting probe driving transformer.

[0076] (vi) The signal processing circuit amplifies and filters the echo signal received by the ultrasonic receiving probe, and the main control chip performs AD sampling analysis.

[0077] In summary, this invention achieves natural brightness adjustment—"darker near, brighter far"—through real-time ultrasonic ranging combined with an adaptive dimming algorithm. This intelligent dynamic dimming eliminates the need for manual operation, as the lighting brightness dynamically changes with distance, avoiding visual fatigue caused by excessively strong or dim light and significantly improving user comfort. This invention is highly energy-efficient, reducing ineffective energy consumption. When the user leaves the detection area, the system automatically dims or turns off the light, and brightens as needed when the user approaches. Actual measurements show that compared to traditional fixed brightness modes, it can reduce ineffective energy consumption by 30%-50%, aligning with the trend of green lighting development. This invention also boasts high anti-interference capability and system stability. Employing bidirectional signal processing technology, the transmitter optimizes energy transmission through push-pull drive and transformer boost, while the receiver integrates bandpass filtering and differential amplification circuits to effectively suppress environmental noise. Furthermore, the system's false trigger rate is less than 2% in complex home environments, demonstrating significantly higher reliability than traditional infrared solutions.

[0078] Although embodiments of the invention have been shown and described, it will be understood by those skilled in the art that various changes, modifications, substitutions and alterations can be made to these embodiments without departing from the principles and spirit of the invention, the scope of which is defined by the appended claims and their equivalents.

Claims

1. An ultrasonic dynamic dimming LED driving control circuit, characterized in that: The system includes a microprocessor, an optocoupler isolation circuit, an LED light source, an LED constant current dimming drive circuit, an isolated DC power source, an ultrasonic receiving circuit, an ultrasonic transmitting circuit, and a signal processing circuit. The LED constant current dimming drive circuit and the isolated DC power source are connected to 220VAC AC power. The isolated DC power source is connected to the microprocessor, the optocoupler isolation circuit, the ultrasonic receiving circuit, and the ultrasonic transmitting circuit. The microprocessor includes a main control chip. The PWM2 pin of the main control chip is connected to the optocoupler isolation circuit, which is connected to the LED constant current dimming drive circuit. The LED constant current dimming drive circuit is connected to the LED light source. The PWM1 pin and DAC pin of the main control chip are both connected to the ultrasonic transmitting circuit. The ultrasonic transmitting circuit is connected to the ultrasonic receiving circuit via ultrasonic transmitting and receiving probes. The ultrasonic receiving circuit is connected to the ADC pin of the main control chip via the signal processing circuit.

2. The ultrasonic dynamic dimming LED driving control circuit according to claim 1, characterized in that: The LED constant current dimming drive circuit includes a rectifier bridge DB1 and a chip U7. Pin 1 of the rectifier bridge DB1 is connected to the neutral line N, pin 2 of the rectifier bridge DB1 is connected to the live line L, pin 3 of the rectifier bridge DB1 is connected to pin 8 of the chip U1, the negative terminal of the freewheeling diode D7, one end of the electrolytic capacitor CE1, and the positive terminal of the LED light source. Pins 5 and 6 of the chip U7 are connected to the positive terminal of the freewheeling diode D7 and one end of the power inductor L2, respectively. The other end of the power inductor L2 is connected to the other end of the electrolytic capacitor CE1 and the negative terminal of the LED light source, respectively. Pin 1 of the chip U7 is connected to a resistor R19, and the other end of the resistor R19 and pin 4 of the rectifier bridge DB1 are both connected to the ground terminal. Pin 2 of the chip U7 is connected to the optocoupler isolation circuit.

3. The LED driving control circuit for ultrasonic dynamic dimming according to claim 1, characterized in that: The optocoupler isolation circuit includes an optocoupler U8. Pin 1 of optocoupler U8 is connected to a 3.3V DC constant voltage power supply. Pin 2 of optocoupler U8 is connected to the collector of transistor Q1. The base of transistor Q1 is connected to one end of resistors R11 and R13 respectively. The other end of resistor R11 is connected to the microprocessor. The emitter of transistor Q1 and the other end of resistor R13 are connected to signal ground respectively. Pin 4 of optocoupler U8 is connected to a 5V DC constant voltage power supply. Pin 3 of optocoupler U8 is connected to one end of resistors R17 and R18 respectively. The other end of resistor R17 is connected to one end of capacitor C9 and the LED constant current dimming driver circuit respectively. The other ends of resistor R18 and capacitor C9 are connected to the ground terminal respectively.

4. The ultrasonic dynamic dimming LED driving control circuit according to claim 1, characterized in that: The ultrasonic receiving circuit includes an amplifier U3. The output terminal of the amplifier U3 is connected to one end of the output coupling capacitor C3 and the feedback resistor R5. The other end of the output coupling capacitor C3 is connected to the signal processing circuit. The other end of the feedback resistor R5 and the negative input terminal of the amplifier U3 are connected to one end of the resistor R10. The positive input terminal of the amplifier U3 is connected to a 1.25V DC reference voltage, a resistor R6, and one end of the capacitor C4. The other end of the capacitor C4 is connected to one end of the resistor R7, the positive terminal of the diode D1, the negative terminal of the diode D2, and pin 1 of the ultrasonic receiving probe TR1. Pin 2 of the ultrasonic receiving probe TR1, the positive terminal of the diode D2, the negative terminal of the diode D1, and the other ends of resistors R7, R6, and R10 are all connected to the signal ground.

5. The ultrasonic dynamic dimming LED driving control circuit according to claim 1, characterized in that: The signal processing circuit includes a bandpass filter operation chip U2. The positive input terminal of the bandpass filter operation chip U2 is connected to one end of resistor R9 and capacitor C2, respectively. The other end of capacitor C2 is connected to one end of resistor R1, resistor R2 and capacitor C5, respectively. The other end of resistor R2 is connected to the ultrasonic receiving circuit. The output terminal of the bandpass filter operation chip U2 is connected to the other end of resistor R1, capacitor C1 and one end of resistor R4, respectively. The other end of resistor R4 and the negative input terminal of the bandpass filter operation chip U2 are connected to one end of resistor R8, respectively. The other end of capacitor C1 is connected to pin 3 of instrumentation amplifier U1. Resistor R3 is connected in parallel to pins 1 and 8 of instrumentation amplifier U1. Pin 6 of instrumentation amplifier U1 is connected to the microprocessor. Pin 2 of instrumentation amplifier U1, the other end of resistor R8, resistor R9 and capacitor C5 are connected to signal ground, respectively.

6. The LED driving control circuit for ultrasonic dynamic dimming according to claim 1, characterized in that: The ultrasonic transmitting circuit includes a frequency amplitude superposition circuit, a push-pull amplification circuit, and a transformer drive switch circuit connected in sequence.

7. The ultrasonic dynamic dimming LED driving control circuit according to claim 6, characterized in that: The frequency amplitude superposition circuit includes an amplifier U5 and an arithmetic unit U6. The positive input terminal of the amplifier U5 is connected to the microprocessor, and the negative input terminal of the amplifier U5 is connected to one end of resistors R14 and R15, respectively. The positive input terminal of the arithmetic unit U6 is connected to the microprocessor, and the negative input terminal and output terminal of the arithmetic unit U6 are both connected to one end of coupling capacitor C7. The other end of resistor R15 and the output terminal of amplifier U5 are connected to the base of transistor Q2, respectively. The other end of coupling capacitor C7 is connected to the emitter of transistor Q2 and one end of coupling capacitor C8, respectively. The collector of transistor Q2 is connected to a +15V DC constant voltage power supply, and the other end of coupling capacitor C8 is connected to a push-pull amplifier circuit.

8. The ultrasonic dynamic dimming LED driving control circuit according to claim 7, characterized in that: The push-pull amplifier circuit includes transistors Q3 and Q5. The collector of transistor Q3 is connected to one end of resistor R12 and a +15V DC constant voltage power supply. The other end of resistor R12 and the base of transistor Q3 are connected to the positive terminal of clamping diode D3. The negative terminal of clamping diode D3 is connected to the positive terminal of clamping diode D4. The negative terminal of clamping diode D4 is connected to the other end of capacitor C8, one end of resistor R16, and the base of transistor Q5. The other end of resistor R16 and the collector of transistor Q5 are both connected to a -15V DC constant voltage power supply. The emitters of transistors Q3 and Q5 are connected to a transformer drive switching circuit.

9. The ultrasonic dynamic dimming LED driving control circuit according to claim 8, characterized in that: The transformer drive switching circuit includes a MOSFET Q4. The gate of MOSFET Q4 is connected to the emitters of transistors Q3 and Q5, respectively. The drain of MOSFET Q4 is connected to one end of inductor L1 and capacitor C6, respectively. The other end of inductor L1 is connected to a +15V DC constant voltage power supply. The other end of capacitor C6 is connected to one end of the primary coil of transformer T1. The secondary coil of transformer T1 is connected in parallel with ultrasonic transmitting probe TR2. The other end of resistor R14 and the other end of the primary coil of transformer T1 are both connected to signal ground.

10. A method for implementing an ultrasonic dynamic dimming LED driving control circuit according to any one of claims 1-9, characterized in that, Includes the following steps: (i) The main control chip is responsible for outputting the dimming control signal PWM2, the ultrasonic transmission frequency control signal PWM1 and the ultrasonic transmission amplitude control signal DAC, and at the same time performs AD sampling on the echo signal after ultrasonic reception and processing. (ii) The optocoupler isolation circuit realizes the opto-isolated transmission of the dimming control signal PWM2 of the low-voltage main control section and the PWM dimming input signal of the LED constant current dimming drive circuit of the high-voltage section. (III) The LED constant current dimming drive circuit realizes the dimming current control of the LED light source; (iv) The ultrasonic transmitting probe is used to transmit ultrasonic signals, and the ultrasonic receiving probe is used to receive echo signals. (V) The ultrasonic transmitting circuit superimposes the ultrasonic transmission amplitude signal and frequency signal to enhance the driving capability of the ultrasonic carrier control signal and realize the driving of the primary coil of the ultrasonic transmitting probe driving transformer. (vi) The signal processing circuit amplifies and filters the echo signal received by the ultrasonic receiving probe, and the main control chip performs AD sampling analysis.

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