Up / down voltage regulation circuit for a group of Christmas lights

Abstract

A boost / step-down voltage regulation circuit for a string of lights, characterized in that it comprises a power supply input circuit; further comprising: a voltage converter circuit connected to the power supply input circuit, which stabilizes and converts an input voltage and regulates the lighting string voltage; a load detection circuit connected to the voltage converter circuit, which automatically detects the number of connected lighting strings and their operating state; a control module connected to the load detection circuit, which processes the boost / step-down regulation, brightness setting, and mode switching; and a human-machine interface module connected to the control module, which is responsible for processing user operations and status feedback.

Description

Technology sector

[0001] This utility model application relates to the field of power electronics, in particular the technology of real-time input voltage measurement with feedback control, as well as the optimization of intelligent lighting systems and their power supply management through load-adaptive control and open-circuit protection mechanisms. Specifically, it relates to a step-up / step-down voltage control circuit for a string of lights. Technical background

[0002] LED lighting systems are already widely used in various sectors, including interior lighting, automotive lighting, and agricultural lighting, due to their advantages such as energy efficiency, long lifespan, and low maintenance requirements. In application scenarios with highly fluctuating input voltage or where dynamic adjustment of the output voltage according to the load is required, buck-boost converters handle these complex power supply management demands.

[0003] The buck-boost converter regulates the voltage by controlling the switching times and utilizing the short-term energy storage and release in an inductor. Depending on the load current, it can operate in continuous conduction mode (CCM) or discontinuous conduction mode (DCM), which affects the voltage regulation characteristics. In CCM, the buck-boost converter exhibits a right-half-plane zero (RHPZ), which causes a non-minimum-phase response, limits the bandwidth of the control loop, and impairs the dynamic response speed of the system. This results in a number of technical problems: (1) Power supply adapters available on the market vary considerably in type and output voltage range. When selecting and installing an LED linear lighting system, users must therefore choose a power supply adapter specifically suited to the respective LED linear lighting system. For example, a power supply adapter with a fixed output voltage may not meet the requirements of LED linear lighting systems of different lengths or configurations if their operating voltage range is narrowly defined. Furthermore, fixed power supply concepts restrict the application range of flexibly configurable LED linear lighting systems (e.g., in automotive lighting or specialized agricultural irradiation). (2) In practice, the input voltage is often subject to fluctuations, for example due to unstable mains voltage or changing energy generation in photovoltaic systems. Conventional LED drivers are usually designed for a specific input voltage range. If the input voltage is outside this range, the operating current and brightness of the LED strip can change significantly, leading to flickering, uneven brightness, or even damage to the LED chips. For example, solar-powered LED lighting systems are affected by changing light intensity and the associated input voltage fluctuations. (3) LED light strips typically consist of several LED strings connected in parallel or series. In systems with parallel LED strings, an unbalanced current distribution can cause some LEDs to be overloaded, shortening their lifespan or resulting in uneven luminous flux decay. Furthermore, conventional LED drivers cannot accurately detect the number of connected LED strings or changes in their forward voltage, making it difficult to dynamically adjust the output voltage and current to the actual load.

[0004] Therefore, the development of a boost / decrease LED linear lighting system that combines adaptive voltage regulation, precise load detection, and compatibility with a wide input voltage range is of great importance for improving the reliability, efficiency, and flexibility of LED lighting systems. Against this background, the present utility model proposes a boost / decrease control circuit for linear lighting systems. Content of the utility model

[0005] Against this background, one objective of the embodiments of the present utility model application is to provide a step-up / step-down voltage regulation circuit for a string of lights in order to solve or mitigate the technical problems present in the existing technology - namely the low adapter compatibility, weak input voltage matching capability and low load detection accuracy - and thereby offer at least one advantageous alternative.

[0006] The technical concept of the present invention is implemented as follows: A step-up / step-down voltage regulation circuit for a string of lights, comprising a power supply input circuit that receives a broadband input of 3 V–30 V and is adapted to various power supply adapters; further comprising: a voltage converter circuit connected to the power supply input circuit, which stabilizes and converts the input voltage and regulates the lighting band voltage; a load detection circuit connected to the voltage converter circuit, which automatically detects the number of connected light strips and their operating status; a control module connected to the load detection circuit, which handles the up / down control, brightness setting and mode switching; and a human-machine interface module connected to the control module, which is responsible for executing the processing of user operations and status feedback.

[0007] In one embodiment, the power supply input circuit comprises: a DCIN connector for receiving a broadband input voltage of 3-30 V, the positive terminal of which is connected to the subsequent circuit and the negative terminal of which is grounded; the input voltage is connected to the VIN pin of the LDO voltage regulator after filtering; The anode of the power supply indicator LED1 is connected to the LDO output or the DCIN positive terminal via a series resistor; the cathode is grounded. The LDO voltage regulator U1 with 3-30 V input, 3 V output and an output current ≥ 500 mA has its VIN pin connected to the DCIN positive terminal, its VOUT pin outputs 3 V to the main control MCU and other low voltage components, and its GND pin is grounded.

[0008] In one embodiment, the input filter capacitors C1 / C2 are connected in parallel between the DCIN positive and negative terminals in the power supply input circuit, with one end connected to the DCIN positive terminal and the other end grounded.

[0009] The power supply input circuit can be summarized as follows: Power supply input path: DCIN positive terminal → filter capacitor → LDO_VIN → LDO_VOUT → MCU power supply connector; Display control: LDO_VOUT → series resistor → LED1 anode → LED1 cathode → ground; Ground network: All component GND pins, capacitor negative terminals and DCIN negative terminal are connected to ground.

[0010] In one embodiment, the voltage converter circuit comprises: an LDO voltage regulator that provides a stable 3V supply and protects downstream circuits from input voltage fluctuations; a main control MCU whose ADVIN pin samples the DCIN input voltage, whose 3V supply pin is connected to the LDO_VOUT connector, whose ADCCUR pin is connected to the sense resistors R32 / R33 to detect the output current, and which simultaneously controls the boost / drag circuit; Measuring resistors R32 / R33, which are connected in series in the output circuit and detect the current signal via the ADCCUR pin; they are responsible for determining the number of connected light strips (0-10 strings) and the current state in order to implement load-adaptive control.

[0011] In one embodiment, the following applies: The LDO voltage regulator VIN is connected to the DCIN positive terminal (3-30 V input), and VOUT outputs 3 V to the MCU and touch chip. The PWM1 / PWM2 pins of the main control MCU output complementary signals to synchronously control the step-up / step-down switching. The up / down control circuit includes: an N-MOSFET Q18, which acts as a switching transistor to control the inductance energy storage and uses the PWM signal to perform the step-up / step-down conversion; An inductive energy storage element connected in series with the N-MOSFET Q18, which stores energy in boost mode and releases energy in boost mode; dual capacitors C5 / C6 connected in series with the N-MOSFET Q18; they serve for energy storage and filtering, compensate for voltage spikes and ensure a stable output.

[0012] The connection logic for the power supply input circuit is as follows: (1) Power supply input path: DCIN positive terminal → LDO_VIN → LDO_VOUT → MCU power supply connection. (2) Voltage detection path: DCIN positive terminal → ADVIN pin → ADC sampling in the MCU. (3) Energy transfer for up / down conversion: DCIN positive terminal → Inductance energy storage → PWM-controlled release → Filtering by output capacitors → Supply of the light strip.

[0013] The control logic includes: (1) Upward conversion mode (Boost mode): If the input voltage is less than the output requirement, complementary modulation of PWM1 / PWM2 takes place. The inductor stores energy for the boost conversion, and after filtering by C5 / C6, the output is provided. (2) Downward conversion mode (Buck mode): If the input voltage is greater than the output requirement, the duty cycle of the PWM is adjusted, and the inductor releases energy to perform the step-down conversion. (3) Current sensing and protection: R32 / R33 detect the output current. When idle, the upward output is automatically switched off after 5 seconds.

[0014] In one embodiment, the load detection circuit comprises: Measuring resistors R32 / R33 are connected in series in the light strip output circuit, with the sampling point connected to the ADCCUR pin of the MCU. The output current is reflected in the voltage drop across these resistors to determine the number of connected light strips (0-10 strings) and the current state.

[0015] An N-MOSFET Q18, whose source is grounded, whose drain is connected to the negative terminal of the light strip, and whose gate is controlled by the LOADEN signal of the main control MCU. It serves as an output switch, controls the turning on / off of the light strip, and supports the open-circuit protection logic.

[0016] A LOAD-D pin sensing element connected to the output circuitry detects the output state. It recognizes whether the output is operating normally; an anomalous level at this pin triggers protection.

[0017] The main control MCU, whose ADCCUR pin receives the signal from the measuring resistor, converts it into a digital value and performs a load analysis.

[0018] The signal transmission logic for the current in the load detection circuit is: measuring resistor → ADCCUR pin → internal ADC of the MCU → load state determination.

[0019] The main control MCU adjusts the duty cycle of PWM1 / PWM2 based on the load state, controls the energy storage / release of the inductor, and thus implements the boost / boost control. Upon detecting an idle state, the MCU switches off the boost output (via PWM control) after 5 seconds and deactivates the display function.

[0020] In one embodiment, the control module comprises: a PT8M2102S8 touch chip that communicates with the main control MCU via an I2C interface and receives commands from capacitive touch buttons; an infrared receiver whose data pins are connected in parallel to the GPIO pins of the main control MCU; the main control MCU decodes the received signals and executes the corresponding commands.

[0021] The control sequence of the control module is as follows: S1, Power-on initialization: The ADVIN pin samples the input voltage (3-30V) → determining the reference value; LOADEN is set to low → Q18 is switched off → the up / down output voltage is at least 3V. S2, recording of the load connection: The level at the LOAD-D pin is checked. A low level indicates a normal state, after which the light band detection takes place. A high level causes the output to be switched off after 5 seconds. S3, Dynamic voltage regulation: The ADCCUR pin samples the current. If it falls below a threshold, PWM1 / PWM2 initiate the step-up process → the output voltage is gradually increased up to 30V. If the current meets expectations, the PWM duty cycle is fixed to maintain a stable output. S4, Idle Protection: If no current is detected, the circuit switches off the step-up / step-down conversion and the display function after 5 seconds.

[0022] In one embodiment, the human-machine interface module includes a seven-segment display. This is connected to the GPIO pins of the main control MCU via a display control circuit (shift register / latch).

[0023] The signal transmission paths are: Touch signal → I2C / GPIO → Main control MCU → Execution of the corresponding action (e.g. brightness control). Infrared signal → GPIO → MCU decoding → execution of remote control commands. Display signal → generated by the main control MCU → GPIO output → control circuitry → display on the seven-segment display. Power supply: All components are powered by the LDO (HC20LR2050) with a stabilized 3V supply to ensure reliable operation.

[0024] In one embodiment, the circuit further includes a protection module that is connected to the other modules and monitors the ADCCUR current signal to trigger automatic shutdown of the upward output.

[0025] Protection signals (open circuit / overcurrent / short circuit) are transmitted via the ADCCUR and LOADEN pins to the main control MCU, which triggers the protective measures. The main control MCU then uses the PWM1 / PWM2 signals to control the voltage converter circuit with negative feedback in order to switch off or regulate the output.

[0026] The LOADEN pin signal controls the switching on / off of the N-MOSFET Q18, thus coordinating the load connection with the protection circuitry. The protection measures act directly on the boost / drag drive circuitry via the PWM signals to quickly interrupt or regulate the output. (1) Idle protection: The output current is sampled via the ADCCUR pin. If no current corresponding to the lighting strip's requirements (e.g., 50mA per string) is detected for 5 seconds, the protection is triggered. The LOADEN pin signal switches off the N-MOSFET Q18, stopping the boost conversion and the display function. The LOADEN pin is connected to the load detection circuit and receives the current signal via the measuring resistors R32 / R33. (2) Overcurrent protection: The ADCCUR pin monitors the current in real time and compares it to a preset threshold (e.g., 120% of the rated current). If this threshold is exceeded, the protection is triggered. The main control MCU uses PWM control to switch off the boost / drag output to prevent damage to the circuit from overload. It is connected to the voltage converter circuit and directly controls the output state via the PWM signals. (3) Short-circuit protection: Triggered by a sudden, sharp increase in current or a rapid drop in voltage. The reaction speed is faster than with open-circuit / overcurrent protection. Can immediately shut down the PWM output and interrupt the power supply path.

[0027] In comparison to the prior art, the mechanisms of the present invention for solving the shortcomings of conventional technical solutions are as follows: (1) Regarding the problem of low adapter compatibility: The power supply input module of the present invention supports a wide voltage range of 3 V to 30 V and is compatible with common adapters such as 3 V / 12 V / 24 V. The HC20LR2050 chip stabilizes the input voltage at 3 V, thus eliminating the influence of adapter variations on downstream circuitry. In idle mode, the output automatically switches off after 5 seconds, thereby preventing adapter idle losses. (2) Regarding the poor input voltage matching capability: The ADVIN pin detects the input voltage in real time. Complementary modulation of PWM1 / PWM2 excites the inductor to store / release energy, thus achieving boost conversion (3 V → 30 V) or buck conversion (30 V → 3 V). The output supports a continuously adjustable voltage from 3 V to 30 V, meeting the requirements of single or dual LED strips. Dual capacitors C5 / C6 smooth out transient voltage spikes and ensure a stable output voltage. (3) Regarding the low accuracy of load detection: The ADCCUR pin precisely measures the output current via the measuring resistors R32 / R33 and determines the number of light strip strings (0-10 strings). The LOAD-D pin detects whether the output circuit is operating normally, thus preventing misinterpretations. The MCU dynamically adjusts the PWM duty cycle based on the sampled current, thereby achieving precise voltage adjustment in response to load changes.

[0028] In comparison to the prior art, the advantageous effects of the present invention are as follows: I. Adapter compatibility and power supply management optimization: The present invention supports an input range of 3 V to 30 V and is compatible with most commercially available power supply adapters. It eliminates the problems of conventional solutions, such as failure to start or voltage instability due to adapter incompatibility. The HC20LR2050 LDO chip stabilizes the input voltage at 3 V, isolates the influence of adapter variations on downstream circuitry, and increases system stability. The idle power-saving protection mechanism automatically shuts off the output after 5 seconds of no load, reducing the adapter's idle losses and extending its lifespan. II. Enhanced input voltage adaptability: Complementary modulation of PWM1 / PWM2 achieves a wide voltage regulation range of 3 V–30 V input to 3 V–30 V output. Both single and dual LED strips can operate stably. The dual capacitors C5 / C6 work in conjunction with inductive energy storage to eliminate transient voltage spikes; the output voltage fluctuation is < ±1%. The ADVIN pin monitors the input voltage in real time and dynamically adjusts the PWM duty cycle to ensure that the output voltage precisely meets the load requirements. III. Optimization of load detection and safety protection: The ADCCUR pin, via the measuring resistors R32 / R33, achieves current sensing at a level of 0.1 mA and precisely determines the connection status of 0-10 light strip strings. The LOAD-D pin senses the state of the output circuit and avoids misinterpretations due to contact problems, thus significantly improving sensing accuracy. Explanation of the figures

[0029] To clarify the technical solutions in the embodiments of this application or in the prior art, the figures necessary for explaining the embodiments or describing the prior art are briefly presented below. Naturally, the figures shown in the following description represent only some embodiments of this application. A person skilled in the art can derive further figures from these without inventive step. Fig. Figure 1 shows the circuit diagram of the dual light strip output control of the present utility model. Fig. Figure 2 shows a schematic representation of the light band display section of the present utility model. Fig. Figure 3 shows the circuit diagram of the light strip display section of the present utility model. Fig. Figure 4 shows the circuit diagram of the power supply input section of the present utility model. Fig. Figure 5 shows the circuit diagram of the up / down control section of the present utility model. Fig. Figure 6 shows the circuit diagram of the infrared receiver section of the present utility model. Fig. Figure 7 shows a representation of the TK keypad user interface of the present utility model. Fig. Figure 8 shows a schematic connection diagram of the main control MCU of the present utility model. Fig. Figure 9 shows an oscillogram from experiment 1. Fig. Figure 10 shows the thermal relationship diagram of input voltage to output voltage from experiment 1. Fig. Figure 11 shows a thermal diagram of the current fluctuations from experiment 1. Fig. Figure 12 shows a line graph of the output voltage stability from experiment 1. Fig. Figure 13 shows a scatter plot of the current measurement errors from experiment 2. Fig. Figure 14 shows a boxplot diagram of the trip times for the idle protection from test example 2. Fig. Figure 15 shows a line graph of the output voltage stability from experiment 2. Specific details

[0030] To clarify and make more understandable the aforementioned objectives, features, and advantages of the present utility model, the specific embodiments of the utility model are explained in detail below with reference to the drawings. Many specific details are presented in the following description to enable a comprehensive understanding of the utility model. However, the utility model can be implemented in many other ways that differ from those described here. Those skilled in the art can make similar improvements without infringing the core of the utility model. Therefore, the utility model is not subject to the limitations of the specific embodiments disclosed below. Embodiment 1. As shown in the Fig. 1, Fig. 2, Fig. 3, Fig. 4, Fig. 5, Fig. 6, Fig. 7 to Fig. As shown in Figure 8, this example will provide a concrete embodiment of the step-up / step-down voltage regulation circuit for a group of Christmas lights. It comprises, in detail: S1, power supply input and stabilization phase: DCIN accepts a wideband input voltage of 3-30 V and is compatible with common market adapters. The LDO stabilizes the input voltage at 3 V and isolates downstream circuitry from voltage fluctuations. LED1 is connected in series with the power supply path via a series resistor and visually indicates the power-on status. Specifically, the LDO keeps the output voltage constant through a negative feedback mechanism, thus ensuring the stable operation of the main control MCU and other low-voltage components. S2, voltage detection and control phase: ADVIN samples the input voltage in real time and provides the MCU with the basis for dynamic control. The complementary modulation of PWM1 / PWM2 controls the energy storage / release of the inductor to achieve boost conversion (3 V → 30 V) or buck conversion (30 V → 3 V). Capacitors C5 / C6 smooth out transient voltage spikes. Specifically, the MCU adjusts the PWM duty cycle based on the sampled voltage to achieve a precise adjustment of the output voltage. S3, load connection and detection phase: Q18 is controlled by the LOADEN signal and serves as an output switch. The LOAD-D pin detects the state of the output circuit; a low level indicates a normal state. The ADCCUR pin detects the output current via measuring resistors and determines the number of light strip strings (0-10 strings). It is understandable that this example has a dual verification mechanism (pin level + current sampling) which can effectively ensure the accuracy of the load condition detection. S4, Control of the display and operating elements: LEDs 1-LED4 are controlled via PWM for brightness / flashing mode control. The seven-segment display shows the level (10 levels), timer (3H / 5H / 8H), and brightness (25% / 50% / 75% / 100%). The infrared receiver supports 360° remote control with a response time of < 200 ms. The touch chip enables waterproof and fault-tolerant operation and replaces traditional mechanical buttons.

[0031] Example 2. As in the Fig. 2 to Fig. Figure 3 shows. Building on embodiment 1, this example further provides a concrete concept for the input voltage sensing of the power supply adapter and the output voltage control.

[0032] In this embodiment, the input voltage detection relates to: The LDO HC20LR2050 stabilizes the broadband voltage input from DCIN (3-30 V) to 3 V and isolates downstream circuits from input fluctuations. It features an input voltage range of 3-30 V and an output voltage accuracy of ±1% in an SOT-23 package. Simultaneously, it offers load regulation of 0.05% / mA and full-load efficiency > 85%.

[0033] The ADVIN pin of the main control MCU samples the input voltage value in real time and serves as the basis for up / down decisions. A 12-bit ADC converts the analog voltage into a digital signal with a sampling accuracy of 0.1 V. The voltage sensing range is 3-30 V, and the response time is less than 1 ms.

[0034] In this embodiment, the output voltage control relates to: Complementary modulation of PWM1 / PWM2. By controlling the energy storage / release of the inductor, boost conversion (3 V → 30 V) or buck conversion (30 V → 3 V) is achieved. Boost conversion is initiated when the input voltage is less than the output requirement; otherwise, buck conversion is achieved by switching off the PWM.

[0035] Furthermore, the inductor and the dual capacitors C5 / C6 store energy for the boost conversion, with the dual capacitors filtering transient spikes. The inductance value is selected based on the output current, and the capacitance of C5 / C6 is 10-100 µF with a voltage rating of 50 V. The output voltage fluctuation is < ± 1%, and the ripple suppression is > 40 dB. Additionally, the sense resistors R32 / R33 detect the output current and determine the number of optical strings (0-10 strings) as well as the load condition. Their resistance is 10 mΩ ± 1% in an 0805 package with a power dissipation of 0.1 W. Simultaneously, the ADCCUR pin samples the voltage drop, and the MCU calculates the current value using Ohm's law.

[0036] It should be noted that on the input side: The LDO supports a wide input of 3-30 V, is compatible with over 90% of commercially available adapters, and eliminates the compatibility problems of traditional solutions.

[0037] It should be noted that on the output side: The wide output range of 3-30 V adapts to the requirements of single / dual light strips through dynamic PWM control.

[0038] The intelligent control logic lies in the voltage sensing → decision → execution loop: ADVIN sampling → MCU calculation of the duty cycle → PWM control of the inductor energy storage → filtering and output via C5 / C6. Based on the load current, PWM parameters are automatically adjusted to achieve seamless brightness / level changes.

[0039] The integrated protection mechanism concept includes: (1) Idle protection: Automatically shuts off the output after 5 seconds without power to reduce idle losses of the adapter. (2) Overcurrent protection: If the ADCCUR current exceeds a threshold value, the PWM is switched off to prevent circuit overload. (3) Short-circuit protection: In the event of a sudden, strong increase in current, the output is immediately interrupted; response time < 1 ms.

[0040] Example 3. As in Fig. 1 shown. Building on embodiment 1, this example further provides a concrete concept for dual-band light output control.

[0041] During the initialization phase, the main control MCU (MM32G0141C4N) performs system initialization, configures the state of the ADVIN, PWM1 / PWM2, ADCCUR, etc. pins, and prepares to receive voltage / current measurement data. The LDO voltage regulator stabilizes the voltage input from DCIN (3-30 V) to 3 V and supplies power to the MCU and low-voltage components.

[0042] Specifically, the input voltage sensing mechanism consists of the following: The ADVIN pin samples the input voltage (3-30 V) in real time and confirms whether the voltage range meets the requirements.

[0043] Specifically, the output circuit validity test consists of the following: Q19 (N-MOS) detects the level at the LOAD-D pin; a low level indicates that the output circuit is operating normally. This is an N-channel enhancement MOSFET with Vds ≥ 40 V and Id ≥ 5 A.

[0044] Specifically, the light strip connection detection consists of the following: Q18 (N-MOS) serves as an output switch, the on / off switching of which is controlled by the LOADEN signal. The measuring resistors R32 / R33 detect the output current and determine the number of light strip strings (0-10 strings) as well as the load condition.

[0045] Specifically, the voltage regulation phase consists of the following: The complementary modulation of PWM1 / PWM2 controls the boost conversion (3 V → 30 V) or buck conversion (30 V → 3 V) via the regulation of the energy storage / release of the inductor. The inductor and the dual capacitors C5 / C6 store energy for the boost conversion, with the dual capacitors filtering transient voltage spikes.

[0046] Specifically, the handling during load removal consists of the following: Upon detection of power loss, the upward output and the display function are switched off after 5 seconds. If a current threshold is exceeded, the PWM shutdown is triggered to prevent overloading the circuit.

[0047] In this embodiment, the wide input voltage range (3-30 V) allows compatibility with various adapters, with the LDO isolating input fluctuations. On the output side, the PWM duty cycle is automatically adjusted based on the load current to achieve precise output voltage control. The underlying logic is a closed-loop control system of voltage sensing → current sensing → PWM control, which ensures stable operation of the LED strip.

[0048] It should be noted that the Q18 controls the switching on / off of each individual light strip and supports the independent operation of single / dual light strips. Measuring resistors monitor the current of each light strip in real time to prevent overload or imbalance. Based on the number of light strips, the output power is automatically distributed to ensure a stable current for each strip.

[0049] It should be noted that the parameters of the aforementioned critical components are as follows: (1) N-MOS Q18 / Q19: Vds=40V, Id=5A, Rds(on)=20mΩ, TO-220 case. (2) Measuring resistors R32 / R33: resistance value 0.1 Ω ± 1 %, power 0.1 W, housing 0805. (3) Main control MCU: 32-bit, package QFN32, operating voltage 2.0-5.3 V, ADC resolution 12 bits, PWM resolution 16 bits. (4) LED1-LED4: Operating voltage 2 V, brightness adjustable, housing 0805.

[0050] It should be noted that the system performance parameters are as follows: Input voltage range: 3-30 V Output voltage range: 3-30 V Response time: Voltage regulation < 10 ms, protection tripping < 1 ms

[0051] Energy efficiency indicators: Full load efficiency 85%, no-load power loss 0.1 W. Environmental compatibility: Operating temperature -20 °C to 85 °C, EMC class B certification.

[0052] Example 4. As in the Fig. 6 to Fig. Figure 7 shows that, building on embodiment 1, this example further provides a concrete concept for the human-machine interface.

[0053] In the initial phase of human-machine interaction, the capacitive touch chip (PT8M2102S8) detects changes in human body capacity, thus enabling operations such as switching on / off, brightness control, timer setting and step switching.

[0054] Specifically, differential capacitance sensing technology enables waterproof and fault-tolerant operation. The touch signal is transmitted to the main control MCU via the I2C interface and triggers the corresponding operation command. The infrared receiver receives infrared signals with 360° omnidirectional reception and a remote control range of 5-8 meters. The received signal is decoded by the MCU, which then executes commands for brightness, mode, and timer switching. The main control MCU (MM32G0141C4N) integrates touch and remote control signals and controls the PWM output, the seven-segment display, and the LED status indicator. The input voltage is sensed via the ADVIN pin and, combined with the ADCCUR current sampling data, the output parameters are dynamically adjusted.

[0055] Specifically, the seven-segment display shows the level (10 levels), timer (3H / 5H / 8H), and brightness (25% / 50% / 75% / 100%) in real time. Driven by a shift register, the update frequency is 2 Hz without flickering. The LED indicators (LED1-LED4) show the power status (steady / flashing), brightness, and operational feedback. PWM dimming allows brightness control from 0-100% with an adjustable flashing frequency of 1-5 Hz.

[0056] Furthermore, the LDO voltage regulator (HC20LR2050) stabilizes the 3-30 V input at 3 V and supplies power to the MCU and low-voltage components. The power supply input sensing (ADVIN) monitors the input voltage in real time and provides the basis for boost / drag decisions. A voltage divider network converts the input voltage into a 0-3.3 V signal recognizable by the MCU. The N-MOSFET (Q18) serves as an output switch and controls the on / off switching of the light strip; it senses the output current and determines the load state.

[0057] It is understandable that capacitive touch input enables precise close-range operation, while infrared remote control supports remote operation, thus covering all scenarios. The seven-segment display shows operational results in real time, and LED indicators provide status information, forming an operational feedback loop.

[0058] It should be noted that the underlying control logic in this example is as follows: Initialization sequence: Power on → LDO stabilization → MCU initialization → Peripheral configuration → Waiting for input.

[0059] Input detection process: ADVIN sampling of the input voltage → determination of the boost / downward requirement → PWM control of the output.

[0060] Load detection sequence: Q18 activation → current detection via measuring resistor → determination of the load state → regulation of the output voltage.

[0061] Idle protection sequence: 5 seconds without power → Switching off the upward output → Switching off the display function.

[0062] Example 5. As in Fig. Figure 8 shows that, building on embodiment 1, this example further provides a concrete concept for the main control MCU (MM32G0141C4N_QFN32).

[0063] In this example, the initialization and self-test phase concerns: The LDO voltage regulator (HC20LR2050) stabilizes the 3-30 V input at 3 V, supplies power to the MCU and low-voltage components, and ensures a stable operating voltage. After power-up, the main control MCU performs the initialization configuration (pins, PWM, interrupts), samples the input voltage via the ADVIN pin, and confirms the validity of the 3-30 V range.

[0064] The touch chip (PT8M2102S8) completes the capacity sensing initialization and prepares to receive touch operations. The infrared receiver starts 38 kHz carrier frequency detection and prepares to receive remote control signals.

[0065] In this example, the normal operating mode applies: (1) Voltage control logic: Input detection: The ADVIN pin samples the input voltage in real time and dynamically adjusts the PWM duty cycle. Up / down control: Complementary modulation of PWM1 / PWM2 drives the inductor energy storage and realizes 3 V → 30 V up or 30 V → 3 V down conversion. Output stabilization: Filtering by the dual capacitors C5 / C6 ensures an output voltage fluctuation of < ±1%. (2) Load detection: The measuring resistors (R32 / R33) detect the output current and determine the number of light strip strings (0-10 strings) as well as the load condition. If the power is interrupted for 5 seconds, the output is automatically switched off to reduce energy consumption. (3) User interaction processing: The PT8M2102S8 transmits touch commands via the I2C interface; the MCU performs brightness / mode switching. After decoding, the infrared receiver triggers the corresponding operation; response time < 200 ms. The seven-segment display shows level / timer information in real time, LED indicators provide synchronous status information. In this embodiment, the fault handling mode relates to: Overcurrent protection: If the ADCCUR current threshold is exceeded, the PWM shutdown is triggered to prevent circuit damage. Overvoltage protection: If the output voltage exceeds 30 V, the output is immediately interrupted to protect the safety of the light strip. Short-circuit protection: In the event of a sudden, strong current increase, the response time is < 1 ms for rapid fault isolation. (4) Programming interface: A reserved simulation port supports firmware updates for troubleshooting or functional enhancement (e.g. networking, color temperature control).

[0066] Specifically, the core logic of the power supply management is as follows: The input range of 3-30 V is compatible with over 90% of commercially available adapters, the LDO isolates fluctuations and ensures stability for downstream circuits.

[0067] Specifically, this concerns the dynamic control mechanism: Closed control loop of input voltage → PWM duty cycle → output voltage, which implements adaptive control.

[0068] Specifically, the system for load detection and protection includes: a measuring resistor of 0.1 Ω ± 1%, and a current sensing resolution of 0.1 mA for precise determination of the load condition. Open-circuit, overcurrent, and short-circuit protection work together to reduce the error rate by 80%.

[0069] Specifically, the performance parameter indicators are: Input range: 3-30V wideband voltage, compatible with 3V / 12V / 24V adapters. Output range: 3-30 V continuously adjustable, meets the requirements of single / dual light strips. Energy efficiency indicators: Full-load efficiency > 85%, no-load power loss < 0.1 W. Accuracy indicators: 12-bit ADC sampling accuracy, 16-bit PWM resolution. Test example 1. This example aims to verify the voltage adaptation capability. (I) Experimental procedure planning: (1) Testing the input voltage range:

[0070] Independent variable: Input voltage (3-30V, 1V step); Dependent variables: Output voltage, current fluctuation, response time; Procedure: Fixed 50Ω load resistance, stepwise increase of input voltage; Recording of output voltage stability and current fluctuations; Verification of the tripping condition for no-load protection (5 seconds without current); (2) Test when changing the load resistance:

[0071] Independent variable: Load resistance (10-100Ω, step size 10Ω);

[0072] Dependent variables: output voltage, current fluctuation, full-load efficiency;

[0073] Procedure: Fixed input voltage 24V, gradual increase of the load resistance; recording of the output voltage drop and the current fluctuation range; calculation of the full-load efficiency (output power / input power). (3) Dynamic response test:

[0074] Independent variable: Abrupt change in input voltage (e.g., 3V→30V); Dependent variables: Response time of the voltage regulation, overshoot of the output voltage;

[0075] Procedure: Rapid switching of the input voltage, recording of the output voltage settling time; verifying that response time <10ms, overshoot <±2%. (II) Relevant parameters: Parameter item Number range Test conditions Input voltage range 3-30V Full coverage Output voltage range 4.8-29.3V (at full load) Load resistance 100Ω Current fluctuation range -5% ~ +5%, input voltage 24V, load 50Ω Idle protection trigger time 5.0±0.2s No-load state Full load efficiency 85.20%, 24V input, 100Ω load Response time voltage regulation <10ms 3V→30V step change (III) Experimental result:

[0076] This concept achieves excellent voltage adaptability through its design with broadband input voltage (3-30V), dynamic load control and precise no-load protection; Fig. Figure 10 shows that the output voltage increases linearly with increasing input voltage; if the load resistance increases, the output voltage decreases slightly (load effect); Fig. Figure 11 shows that the fluctuations are larger in the high input voltage + low load resistance range (maximum +5%), while they are smaller in the low input voltage + high load range (minimum -3%); Fig. Figure 12 shows that the output voltage varies linearly with the input voltage for different load resistances, with the differences in the slope reflecting the load effect. Fig. Figure 9 shows a full-load efficiency of 85.2%, with current fluctuations controlled within ±5%.

[0077] The test results verify the technical progress of this concept with regard to voltage adaptability.

[0078] Test example 2. This example aims to verify the load detection accuracy. (I) Current sampling accuracy test:

[0079] Independent variables: load resistance (10-200Ω), input voltage (3-30V);

[0080] Dependent variable: Percentage of current sampling error;

[0081] Procedure: Fixed input voltage, gradual increase of the load resistance, recording of the deviation of the current sampled by the ADCCUR pin from the theoretical value; repeat tests to determine the distribution of errors at different input voltages to verify accuracy stability. (II) Test of the trigger time for idle protection:

[0082] Independent variable: duration of the load-free state;

[0083] Dependent variable: Trigger time of the protection;

[0084] Procedure: Remove all loads, start the timer; monitor when the system automatically shuts off the boost output and clears the display; 100 repetitions to calculate the mean and standard deviation. (III) Experimental result parameters: Parameter item, number range, test conditions Load resistance range 10-200Ω Full resistance spectrum test Input voltage range 3-30V Full voltage spectrum test Current sampling error -2% ~ +2% Random error distribution Idle protection trigger time 5.0±0.2s 100 repeat tests (IV) Experimental result

[0085] This concept achieves excellent load detection accuracy through highly precise measuring resistors (R32 / R33) and the MCU's ADC sampling algorithm. As shown in Fig. As shown in Figure 14, the errors are concentrated within the range of ±2%, which corresponds to the design objectives; in the low load and high voltage range, the errors increase slightly (maximum +1.8%), in the high load and low voltage range they decrease slightly (minimum -1.5%); the red dashed line marks the ±2% design threshold, all scatter points lie within the thresholds.

[0086] As in Fig. As shown in Figure 15, the median is 5.0s, the interquartile range is 0.1s, which meets the design requirements of 5.0±0.2s; there are no outliers, the distribution is normal, which verifies the reliability of the protection mechanism.

[0087] As in Fig. As shown in Figure 13, this concept achieves a current sampling error of < ±2% under all operating conditions through the use of high-precision measuring resistors (R32 / R33), which meets the sensing requirements at the 0.1 mA level. Accuracy remains stable in the load resistance range of 10–200 Ω and the input voltage range of 3–30 V, thus verifying the technological advancement of this concept with regard to load sensing accuracy and providing a solid basis for the precise control of intelligent lighting systems.

[0088] The embodiments described above serve only to illustrate the practical applications of the present utility model application. While the description is relatively specific and detailed, it must not be interpreted as limiting the scope of protection of the utility model. It should be noted that those skilled in the art in this field can make several modifications and improvements, all of which fall within the scope of protection of this utility model, without deviating from the concept of the present invention. Therefore, the scope of protection of the utility model must be determined by the accompanying claims.

Claims

A boost / step-down voltage regulation circuit for a string of lights, characterized in that it comprises a power supply input circuit; further comprising: a voltage converter circuit connected to the power supply input circuit, which stabilizes and converts an input voltage and regulates the string of lights; a load detection circuit connected to the voltage converter circuit, which automatically detects the number of connected strings of lights and their operating state; a control module connected to the load detection circuit, which processes the boost / step-down regulation, brightness setting, and mode switching; and a human-machine interface module connected to the control module, which is responsible for processing user operations and status feedback. The control circuit according to claim 1, characterized in that the power supply input circuit comprises: a DCIN connector for receiving a broadband input voltage of 3-30V, wherein the input voltage is connected to this; a power supply LED (LED1), the anode of which is connected to the LDO output or the DCIN positive terminal and the cathode of which is grounded; an LDO voltage regulator (U1), the VIN pin of which is connected to the DCIN positive terminal, the VOUT pin of which outputs 3V to the main control MCU and other low-voltage components, and the GND pin of which is grounded. The control circuit according to claim 2, characterized in that in the power supply input circuit the input filter capacitors C1 / C2 are connected in parallel between the DCIN positive and negative terminals, with one end connected to the DCIN positive terminal and the other end grounded. The control circuit according to claim 1, characterized in that the voltage converter circuit comprises: an LDO voltage regulator providing a 3V supply; a main control MCU whose ADVIN pin samples the DCIN input voltage, whose 3V supply pin is connected to the LDO VOUT terminal, whose ADCCUR pin is connected to the sense resistors R32 / R33 to detect the output current, and which simultaneously controls the boost / drag switching; sense resistors R32 / R33 connected in series in the output circuit and detecting the current signal via the ADCCUR pin. The control circuit according to claim 4, characterized in that: the LDO voltage regulator VIN is connected to the DCIN positive terminal and outputs VOUT 3V to the MCU and touch chip; the PWM1 / PWM2 pins of the main control MCU output complementary signals to synchronously control the boost / drag circuit; the boost / drag control circuit comprises: an N-MOSFET Q18, which, as a switching transistor, controls the inductive energy storage and uses the PWM signal to perform the boost / drag conversion; an inductive energy storage element connected in series with the N-MOSFET Q18; and dual capacitors C5 / C6, which are connected in series with the N-MOSFET Q18. The control circuit according to claim 1, characterized in that the load detection circuit comprises: measuring resistors R32 / R33 connected in series in the light band output circuit, the sampling point being connected to the ADCCUR pin of the MCU; an N-MOSFET Q18, the source of which is grounded, the drain of which is connected to the light band negative terminal and the gate of which is controlled by the LOADEN signal of the main control MCU; a LOAD-D pin sensing element connected to the output circuit to detect the output state; and the main control MCU, whose ADCCUR pin receives the signal from the measuring resistor, converts it into a digital value and performs a load analysis. The control circuit according to claim 1, characterized in that the control module comprises: a touch chip which communicates with the main control MCU via an I2C interface and receives commands from capacitive touch buttons; and an infrared receiver whose data pins are connected in parallel to the GPIO pins of the main control MCU. The control circuit according to claim 1, characterized in that the human-machine interface module comprises a seven-segment display which is connected to the GPIO pins of the main control MCU via a display control circuit. The control circuit according to claim 1, characterized in that it further comprises a protection module that detects the ADCCUR current signal and performs the automatic shutdown of the upward output; wherein the protection signal is transmitted via the ADCCUR and LOADEN pins to the main control MCU, which controls the voltage converter circuit via negative feedback via the PWM1 / PWM2 signals; and the LOADEN pin signal controls the switching on / off of the N-MOSFET Q18. The control circuit according to claim 9, characterized in that: the LOADEN pin signal controls the switching on / off of the N-MOSFET Q18, stops the boost conversion and display function; the LOADEN pin is connected to the load detection circuit and receives the current signal via the measuring resistors R32 / R33; and the ADCCUR pin monitors the current in real time and the main control MCU switches off the boost / drag output via the PWM control.

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