LED driving circuit, controller and LED lighting device

Abstract

The utility model discloses a kind of LED drive circuit, controller and LED lighting device, the LED drive circuit includes boost module, including power input end and boost output end, power input end is electrically connected power supply;Constant-current drive module, including first connecting end and second connecting end, first connecting end is electrically connected boost output end, second connecting end is electrically connected LED module, boost module is used to when the input voltage of power input end is lower than starting threshold, input voltage is promoted to the working voltage required by constant-current drive module;Main control module is electrically connected constant-current drive module, main control module is configured to output control signal to constant-current drive module, to control constant-current drive module work. Boost module can start work under lower input voltage condition, promote low voltage to the working voltage level required by constant-current drive module, ensure that constant-current drive module can be stably started and normally operated, guarantee that LED module can be stably lighted in wider input voltage range.

Description

Technical Field

[0001] This utility model relates to the field of integrated circuit technology, and in particular to an LED driver circuit, controller and LED lighting device. Background Technology

[0002] LEDs, as a new generation of green light source, have become the mainstream choice in the lighting industry. Compared with traditional incandescent and fluorescent lamps, LEDs have significant advantages such as energy saving and environmental protection, long lifespan, fast response speed, and small size, and have been widely used in indoor and outdoor lighting, automotive lighting, displays, backlights, and other fields. To ensure the stable operation of LEDs and extend their lifespan, specialized LED driver circuits are needed to provide constant current or voltage, making LED driver technology a key technical component of LED lighting systems.

[0003] In existing technologies, LED driver chips typically employ a switching mode control method. Their typical operating principle is as follows: the input voltage is directly connected to the chip's power supply pin, and the integrated LDO (Low Dropout Linear Regulator) regulates the input voltage, providing a stable operating voltage for the chip's internal circuitry. The chip uses internal control circuitry and external components to build switching power supply circuits with topologies such as Buck, Boost, or Buck-Boost to achieve constant current driving of the LED. These driver chips, through PWM control, current sensing feedback, and other technologies, can precisely control the LED's operating current and possess comprehensive protection mechanisms such as dimming, overcurrent protection, and overtemperature protection.

[0004] However, existing LED driver chips have obvious technical defects. When the input voltage is lower than the start-up voltage threshold of the LDO inside the chip, the LDO cannot establish a stable output voltage, which causes the internal control circuit of the chip to fail to obtain sufficient operating voltage and thus fail to start. Utility Model Content

[0005] The main purpose of this invention is to propose an LED driver circuit that aims to solve the problem that the LED driver chip cannot establish a stable output voltage when the input voltage is lower than the start-up voltage threshold of the internal LDO.

[0006] To achieve the above objectives, this utility model proposes an LED driving circuit, which includes: The boost module includes a power input terminal and a boost output terminal, wherein the power input terminal is electrically connected to a power source; The constant current drive module includes a first connection terminal and a second connection terminal. The first connection terminal is electrically connected to the boost output terminal, and the second connection terminal is electrically connected to the LED module. The boost module is used to boost the input voltage to the operating voltage required by the constant current drive module when the input voltage at the power input terminal is lower than the start-up threshold. The main control module is electrically connected to the constant current drive module and is configured to output control signals to the constant current drive module to control the operation of the constant current drive module.

[0007] In some embodiments, the boost module includes a boost chip having a first pin and a second pin, the first pin being electrically connected to the power input terminal and the second pin being electrically connected to the boost output terminal.

[0008] In some embodiments, the boost module further includes a first filter capacitor and a second filter capacitor, one end of the first filter capacitor being electrically connected to the first pin and the other end being grounded; one end of the second filter capacitor being electrically connected to the second pin and the other end being grounded.

[0009] In some embodiments, the boost module further includes a flying capacitor, and the boost chip further includes a positive connection terminal and a negative connection terminal, with one end of the flying capacitor electrically connected to the positive connection terminal and the other end electrically connected to the negative connection terminal.

[0010] In some embodiments, the boost module is a voltage doubler charge pump, which includes a clock unit and a voltage doubler unit. The clock unit includes a first input terminal, a first output terminal, and a signal output terminal. The first input terminal is electrically connected to the power input terminal. The voltage multiplier unit includes a second input terminal, a signal receiving terminal, and a second output terminal. The second input terminal is electrically connected to the first output terminal, the signal receiving terminal is electrically connected to the signal output terminal, and the second output terminal is electrically connected to the first connection terminal.

[0011] In some embodiments, the constant current driving module includes a driving chip and a freewheeling module electrically connected between the power supply and the LED module, wherein the control terminal of the driving chip is electrically connected to the control terminal of the freewheeling module.

[0012] In some embodiments, the freewheeling module includes an inductor and a switching transistor. One end of the inductor is electrically connected to a power supply, and the other end is electrically connected to the LED module. The source of the switching transistor is electrically connected to the other end of the inductor, the drain of the switching transistor is grounded, and the gate of the switching transistor is electrically connected to the control terminal of the driver chip.

[0013] In some embodiments, an external boost control module is also included, which includes a third connection terminal, a fourth connection terminal, and a fifth connection terminal. The third connection terminal is electrically connected to a power supply, the fourth connection terminal is electrically connected to the constant current drive module, and the fifth connection terminal is electrically connected to the LED module.

[0014] This invention further proposes a controller, including the aforementioned LED driving circuit.

[0015] The present invention further proposes an LED lighting device, including the controller described in the foregoing embodiment.

[0016] The beneficial effects of this utility model are as follows: By setting an independent boost module, the input power supply voltage is boosted to generate the operating voltage for the constant current drive module, effectively solving the technical problem in the prior art where the circuit cannot work normally when the input voltage is lower than the LDO startup voltage inside the driver chip. Specifically, the boost module can start working under lower input voltage conditions, boosting the low voltage to the operating voltage level required by the constant current drive module, ensuring that the constant current drive module can start and operate stably, thereby ensuring that the LED module can be stably lit within a wider input voltage range. Attached Figure Description

[0017] Figure 1 This is a schematic diagram of the module electrical connections of an embodiment of the LED driver circuit of this utility model; Figure 2 This is a partial circuit diagram of an embodiment of the LED driver circuit of this utility model; Figure 3 This is a partial circuit diagram of an embodiment of the LED driver circuit of this utility model; Figure 4 This is a partial circuit diagram of an embodiment of the LED driver circuit of this utility model.

[0018] Explanation of icon numbers: 100. Boost module; 101. Power input terminal; 102. Boost output terminal; U1, boost converter chip; A1, first pin; A2, second pin; C1, first filter capacitor; C2, second filter capacitor; C3, flying capacitor; A3, positive connection terminal; A4, negative connection terminal; 110. Voltage multiplier charge pump; 111. Clock unit; A5. First input terminal; A6. First output terminal; A7. Signal output terminal; 120. Voltage multiplier unit; A8. Second input terminal; A9. Signal receiving terminal; A10. Second output terminal; 200. Constant current drive module; B1. First connection terminal; B2. Second connection terminal; U2. Driver chip; 201. Freewheeling module; L1. Inductor; Q1. Switching transistor; 300. Main control module; 400. External boost control module; B3. Third connection terminal; B4. Fourth connection terminal; B5. Fifth connection terminal; 500, LED module.

[0019] The realization of the purpose, functional features and advantages of this utility model will be further explained in conjunction with the embodiments and with reference to the accompanying drawings. Detailed Implementation

[0020] The solutions in the embodiments of this utility model will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only a part of the embodiments of this utility model, and not all of them. Based on the embodiments of this utility model, all other embodiments obtained by those of ordinary skill in the art without creative effort are within the protection scope of this utility model.

[0021] It should be noted that all directional indicators (such as up, down, left, right, front, back, etc.) in this utility model embodiment are only used to explain the relative positional relationship and movement of each component in a certain specific posture (as shown in the figure). If the specific posture changes, the directional indicator will also change accordingly.

[0022] It should also be noted that when a component is referred to as "fixed to" or "set on" another component, it can be directly on the other component or may have an intervening component present. When a component is referred to as "connected to" another component, it can be directly connected to the other component or may have an intervening component present.

[0023] Furthermore, the use of terms such as "first" and "second" in this utility model is for descriptive purposes only and should not be construed as indicating or implying their relative importance or implicitly specifying the number of technical features indicated. Therefore, a feature defined as "first" or "second" may explicitly or implicitly include at least one of that feature. Additionally, the technical solutions of the various embodiments can be combined with each other, but only on the basis of being achievable by those skilled in the art. When the combination of technical solutions is contradictory or impossible to implement, such a combination of technical solutions should be considered non-existent and not within the scope of protection claimed by this utility model.

[0024] Reference Figure 1 This utility model provides an LED driving circuit, which includes: The boost module 100 includes a power input terminal 101 and a boost output terminal 102, wherein the power input terminal 101 is electrically connected to a power source. The constant current drive module 200 includes a first connection terminal B1 and a second connection terminal B2. The first connection terminal B1 is electrically connected to the boost output terminal 102, and the second connection terminal B2 is electrically connected to the LED module 500. The boost module 100 is used to boost the input voltage to the operating voltage required by the constant current drive module 200 when the input voltage of the power input terminal 101 is lower than the start-up threshold. The main control module 300 is electrically connected to the constant current drive module 200. The main control module 300 is configured to output control signals to the constant current drive module 200 to control the operation of the constant current drive module 200.

[0025] The technical solution in this embodiment is mainly applied in the field of LED driving, specifically addressing the technical problem that when the input voltage is lower than the start-up voltage threshold of the LDO inside the chip, the LDO cannot establish a stable output voltage, resulting in the internal control circuit of the chip not obtaining sufficient operating voltage and thus failing to start. By setting up an independent boost module 100, the input power supply voltage is boosted to generate an operating voltage for the constant current drive module 200, effectively solving the technical problem in the prior art that the circuit cannot work normally when the input voltage is lower than the start-up voltage of the LDO inside the driver chip U2.

[0026] In this embodiment, the boost module 100 is mainly used to boost the power input to the power input terminal 101, for example, boosting a low input voltage of 2.5V-3.5V to an operating voltage of 5V-12V. The boost module 100 can be implemented using technologies such as a boost converter based on inductor L1, a charge pump, or a switched capacitor boost circuit. For example, a synchronous rectified boost converter with a switching frequency of 100kHz-1MHz can be used to improve conversion efficiency and reduce ripple.

[0027] In this embodiment, the constant current drive module 200 is mainly used to drive the LED module 500 to operate stably. Specifically, it uses constant current control technology to ensure that the current flowing through the LED remains constant, avoiding brightness instability or LED damage caused by voltage fluctuations. The constant current drive principle is based on current sampling feedback control. By detecting the current flowing through the LED and comparing it with a set value, the output is dynamically adjusted to maintain a constant current. The constant current drive module 200 can be implemented using a linear constant current driver, a switching constant current driver, or an integrated constant current drive chip U2 such as PT4115 or AL8861. In this embodiment, the first connection terminal B1 of the constant current drive module 200 is electrically connected to the boost output terminal 102 to obtain an operating voltage that meets the start-up threshold from the boost output terminal 102. For example, when the boost module 100 outputs an 8V voltage, the constant current drive module 200 can stably start up and establish an internal reference voltage. After starting up, a constant current is provided to the LED module 500 through the second connection terminal B2 to achieve stable lighting of the high-power LED beads.

[0028] In this embodiment, the main control module 300 is primarily responsible for regulating the output control signals of the constant current drive module 200. It can output PWM signals, analog voltage signals, or digital control signals. The main control module 300 can be implemented using a microcontroller (such as the STM32 series, Arduino, etc.), a dedicated control chip, or an FPGA. For example, an STM32F103 microcontroller is used, whose PWM output port is used to control the on / off state and output current regulation of the constant current drive module 200. Precise control of LED brightness is achieved by adjusting the duty cycle of the PWM signal (e.g., 10%-100%), while also providing safety functions such as overcurrent protection and overtemperature protection.

[0029] When the input power supply voltage is lower than the startup voltage threshold of the constant current drive module 200 (for example, the input voltage is only 3V, while the constant current drive module 200 requires above 5V to start), the boost module 100 first detects the input voltage signal, and the internal boost controller immediately starts the boost operation mode. The boost module 100 releases the energy stored in the inductor L1 and adds it to the input voltage through the high-frequency switching action of the switching transistor Q1, thereby boosting the 3V input voltage to an 8V operating voltage output.

[0030] The boosted voltage is transmitted to the first connection terminal B1 of the constant current drive module 200 through the boost output terminal 102, providing sufficient operating voltage for the constant current drive module 200. After receiving the required operating voltage, the internal LDO regulator of the constant current drive module 200 starts normally, establishing a stable internal reference voltage and bias circuit, and the control circuit begins to work normally. At the same time, the main control module 300 sends a control signal to the constant current drive module 200, such as an 80% duty cycle PWM signal. After receiving the control signal, the constant current drive module 200 outputs a corresponding constant current to the LED module 500 through the second connection terminal B2, realizing stable LED lighting and brightness adjustment. Throughout the process, the boost module 100 continuously monitors the input voltage changes and dynamically adjusts the boost ratio to ensure a stable and reliable operating voltage for the constant current drive module 200.

[0031] The beneficial effects of this utility model are as follows: By setting an independent boost module 100, the input power supply voltage is boosted to generate the working voltage for the constant current drive module 200, effectively solving the technical problem in the prior art that the circuit cannot work normally when the input voltage is lower than the internal LDO startup voltage of the drive chip U2. Specifically, the boost module 100 can start working under lower input voltage conditions, boosting the low voltage to the working voltage level required by the constant current drive module 200, ensuring that the constant current drive module 200 can start stably and operate normally, thereby ensuring that the LED module 500 can be stably lit within a wider input voltage range.

[0032] Furthermore, this design expands the application scenarios of the LED driver circuit, enabling it to operate normally in low-voltage power supply environments, such as single-cell lithium batteries and solar panels. Secondly, the intelligent control of the main control module 300 achieves precise adjustment of LED brightness and switching between multiple operating modes, improving product flexibility and user experience. Finally, the independent boost module 100 design enhances the overall circuit reliability and modularity, facilitating product maintenance and upgrades. Overall, this technical solution effectively broadens the input voltage operating range of the LED driver circuit, improving system stability and practicality.

[0033] See Figure 2 In this embodiment, the boost module 100 includes a boost chip U1, which has a first pin A1 and a second pin A2. The first pin A1 is electrically connected to the power input terminal 101, and the second pin A2 is electrically connected to the boost output terminal 102.

[0034] In this embodiment, the boost module 100 is implemented using an integrated boost chip U1. This boost chip U1 integrates the core circuitry of the boost converter, including internal switching transistor Q1, an oscillator, an error amplifier, and a reference voltage source, offering advantages such as small size, high efficiency, and fewer external components. The boost chip U1 can be a commonly used boost control chip such as MT3608, XL6009, ME2135, LM2577, or MC34063. Among these, the ME2135 is a high-performance synchronous boost converter chip with a wide input voltage range (2.5V-5.5V), high conversion efficiency (up to 95%), and low quiescent current (less than 100μA), making it particularly suitable for battery-powered LED driver applications.

[0035] The first pin A1 of the boost chip U1 serves as the power input pin (VIN), connected to the power input terminal 101 to receive a low-voltage input signal from an external power source. The second pin A2 serves as the boost output pin (VOUT), connected to the boost output terminal 102 to provide the boosted operating voltage to the constant current drive module 200. In addition, the boost chip U1 includes an enable control pin (EN), a switching node pin (SW), a feedback pin (FB), and a ground pin (GND), which, together with external inductors L1, capacitors, resistors, and other components, form a complete boost circuit.

[0036] The operation of the boost converter chip U1 is as follows: It obtains a low-voltage power signal, such as a 3V lithium battery voltage, from the power input terminal 101 via the first pin A1 (VIN). The internal startup circuit of the boost converter chip U1 first checks whether the input voltage meets the minimum operating requirements. When the input voltage is higher than the undervoltage lockout threshold (e.g., 2.3V), the chip begins normal operation. An internal oscillator generates a fixed-frequency clock signal (typically 1.2MHz), driving the internal power switch Q1 to perform high-frequency switching.

[0037] During the conduction period of switch Q1, inductor L1 stores energy, and the current increases linearly. During the turn-off period of switch Q1, the energy stored in inductor L1 is released to the output capacitor and load through the freewheeling diode, realizing energy transfer and voltage boost. Simultaneously, the feedback circuit continuously monitors the output voltage and compares it with the internal reference voltage. The duty cycle of switch Q1 is adjusted through the error amplifier and PWM controller to ensure the output voltage remains stable at the set value. After internal boost processing, the 3V input voltage is boosted to the 8V threshold voltage. The stable operating voltage is then output to the constant current drive module 200 through the second pin A2 (VOUT) and the boost output terminal 102, providing sufficient startup and operating voltage to ensure that the constant current drive module 200 can properly drive the LED module 500.

[0038] Continue reading Figure 2In this embodiment, the boost module 100 further includes a first filter capacitor C1 and a second filter capacitor C2. One end of the first filter capacitor C1 is electrically connected to the first pin A1, and the other end is grounded. One end of the second filter capacitor C2 is electrically connected to the second pin A2, and the other end is grounded.

[0039] In this embodiment, the first filter capacitor C1 primarily functions as an input filter, removing high-frequency noise and ripple interference from the power input terminal 101 to provide a relatively stable input voltage for the boost chip U1. When external power supplies experience voltage fluctuations or high-frequency interference, the first filter capacitor C1 can smooth out instantaneous changes in the input voltage through its energy storage characteristics, while bypassing high-frequency noise components to prevent these interference signals from entering the boost chip U1 and affecting its normal operation. Furthermore, the first filter capacitor C1 can also provide energy support when the boost chip U1 experiences instantaneous high current demands, improving dynamic response performance.

[0040] The second filter capacitor C2 plays a crucial role in output filtering, primarily smoothing the pulsating voltage of the boost circuit output and reducing output ripple. Since the boost chip U1 operates in a switching mode, its output voltage inherently possesses certain pulsating characteristics and harmonic components from the switching frequency. The second filter capacitor C2 smooths the output voltage pulsation by releasing stored charge during the off-state of the switching transistor Q1 and storing charge during the on-state, thus providing a more stable and low-ripple operating voltage for the constant current drive module 200. This is essential for the stable operation of the subsequent constant current drive module 200, effectively reducing LED output current ripple and improving the luminous efficacy stability of the LED.

[0041] In practical applications, the capacitance of the first filter capacitor C1 can be selected as a ceramic capacitor or tantalum capacitor with a capacitance of 10μF-100μF, which has good high-frequency characteristics; the capacitance of the second filter capacitor C2 is generally selected as an electrolytic capacitor or ceramic capacitor with a capacitance of 22μF-220μF, in order to obtain better filtering effect and smaller output ripple.

[0042] Continue reading Figure 2 In this embodiment, the boost module 100 further includes a flying capacitor C3, and the boost chip U1 further includes a positive connection terminal A3 and a negative connection terminal A4. One end of the flying capacitor C3 is electrically connected to the positive connection terminal A3, and the other end is electrically connected to the negative connection terminal A4.

[0043] In this embodiment, the boost chip U1 adopts a charge pump boost architecture or a multi-stage boost structure, and the flying capacitor C3 is the core component for achieving voltage multiplication. The working principle of the flying capacitor C3 is based on a charge transfer mechanism, achieving voltage boost through a periodic charging and discharging process. The specific working process is divided into two stages: In the first clock cycle, the internal switching circuit of the boost chip U1 connects the flying capacitor C3 to the input power supply for charging, so that the voltage across its terminals is equal to the input voltage; In the second clock cycle, the switching circuit changes the connection method, connecting the charged flying capacitor C3 in series with the input power supply to the output terminal, thereby achieving voltage superposition, and the output voltage can theoretically reach twice the input voltage.

[0044] The primary function of the flying capacitor C3 is as a charge carrier and energy transfer medium, periodically storing and releasing charge between the positive terminal A3 and the negative terminal A4 of the boost chip U1. The positive and negative terminals A3 and A4 are key nodes in the internal switching network of the boost chip U1. By precisely controlling the switching timing of these two ports, the flying capacitor C3 can rapidly switch between charging and discharging states. The capacitance value of the flying capacitor C3 directly affects the boost efficiency and output ripple. Typically, a high-quality ceramic capacitor of 0.1μF-10μF is chosen, requiring low ESR (equivalent series resistance) and good high-frequency characteristics to ensure minimal energy loss during charge transfer.

[0045] Compared to the traditional inductor L1 boost circuit, the charge pump boost scheme using flying capacitor C3 has advantages such as small size, no electromagnetic interference, and low startup voltage, making it particularly suitable for portable and space-constrained LED driver applications.

[0046] See Figure 3 In this embodiment, the boost module 100 is a voltage doubler charge pump 110. The voltage doubler charge pump 110 includes a clock unit 111 and a voltage doubler unit 120. The clock unit 111 includes a first input terminal A5, a first output terminal A6 and a signal output terminal A7. The first input terminal A5 is electrically connected to the power input terminal 101. The voltage multiplier unit 120 includes a second input terminal A8, a signal receiving terminal A9, and a second output terminal A10. The second input terminal A8 is electrically connected to the first output terminal A6, the signal receiving terminal is electrically connected to the signal output terminal A7, and the second output terminal A10 is electrically connected to the first connection terminal B1.

[0047] In this embodiment, the first input terminal A5 is electrically connected to the power input terminal 101 to obtain external power (such as a 3.3V input voltage). After receiving the power, the clock unit 111 starts to work normally, providing a stable operating power to the voltage multiplier unit 120 through the first output terminal A6. At the same time, the signal output terminal A7 outputs a square wave clock signal (typical frequency of 10kHz-1MHz). The second input terminal A8 of the voltage multiplier unit 120 receives the operating power from the clock unit 111. After receiving the clock signal, the signal receiving terminal controls the on / off state of the internal switching network according to the high / low level changes of the clock signal, realizing the periodic transfer of charge and voltage multiplication.

[0048] The clock unit 111 can be implemented using a Schmitt trigger or a multivibrator composed of an operational amplifier, or it can use a 555 timer, a crystal oscillator with a frequency divider, or a dedicated clock generator chip such as NE555 or CD4047. The operational amplifier solution has the advantages of low cost and simple circuitry, and the output clock frequency and duty cycle can be flexibly adjusted through an RC feedback network.

[0049] The voltage multiplier unit 120 can be implemented using a classic Cockcroft-Walton voltage multiplier circuit composed of multiple Schottky diodes and capacitors, or it can be implemented using a synchronous rectification voltage multiplier circuit composed of a MOSFET switch Q1 and a capacitor. In the diode scheme, each voltage multiplier unit 120 includes one diode and one capacitor. The diode plays a unidirectional role in conduction and blocking, while the capacitor is responsible for storing and transferring charge.

[0050] The working principle of voltage multipliers is based on capacitor charging and discharging and the law of conservation of charge. Taking a two-stage voltage multiplier as an example: when the clock signal is high, the first-stage capacitor is charged to the input voltage Vin through the input power supply; when the clock signal becomes low, the charge on the first-stage capacitor is transferred to the second-stage capacitor through the diode. Due to the law of conservation of charge and the series connection of capacitors, the voltage across the second-stage capacitor can reach 2Vin. By cascading multiple stages, a higher voltage multiplication ratio can be achieved. Theoretically, an N-stage voltage multiplier circuit can achieve N times the voltage output.

[0051] It should be noted that the voltage multiplier unit 120 can adopt a multi-stage voltage multiplier structure design, with multiple output nodes on the second output terminal A10, each corresponding to a different voltage multiplication level. For example, the four-stage voltage multiplier charge pump 110 can provide different voltage output options such as 2x, 3x, and 4x. By selecting different second output terminals A10, various operating voltages such as 5V, 8V, and 12V can be obtained to meet the voltage requirements of different constant current drive modules 200.

[0052] The boost module 100, which adopts the voltage doubler charge pump 110 structure, has advantages such as low start-up voltage, no need for inductor L1, compact size, and low electromagnetic interference, and is suitable for battery-powered portable LED driver applications.

[0053] See Figure 4 In this embodiment, the constant current driving module 200 includes a driving chip U2 and a freewheeling module 201 electrically connected between the power supply and the LED module 500. The control terminal of the driving chip U2 is electrically connected to the control terminal of the freewheeling module 201.

[0054] In this embodiment, the driver chip U2, as the core controller of the constant current drive module 200, is responsible for monitoring the current changes of the LED module 500 and outputting corresponding control signals to maintain a constant current output. The driver chip U2 can be a dedicated LED constant current driver chip such as PT4115, AL8861, or MP3302. These chips have built-in current sampling amplifiers, error comparators, PWM controllers, and other functional modules, enabling high-precision constant current control. The driver chip U2 compares the current flowing through the LED with an internally set reference current. When the detected current is lower than the reference value, the output duty cycle is increased; when the detected current is higher than the reference value, the output duty cycle is decreased, thereby maintaining a stable LED current.

[0055] The freewheeling module 201 is electrically connected between the power supply and the LED module 500. It mainly consists of a power switch Q1 (such as a MOSFET) and a freewheeling diode, and regulates the LED current under the control of the driver chip U2. The control terminal of the freewheeling module 201 receives a PWM control signal from the control terminal of the driver chip U2, and controls the switching on and off of the power switch Q1 according to the duty cycle of the PWM signal. When the switch Q1 is on, the current flows from the power supply through the switch Q1 to the LED module 500; when the switch Q1 is off, the current in the LED forms a loop through the freewheeling diode, maintaining the continuity of the current and preventing the LED from flickering or being damaged due to sudden current changes.

[0056] The freewheeling module 201 also features overcurrent protection. When the LED current exceeds the safety threshold, the freewheeling module 201 can quickly turn off the power switch Q1, protecting the LED module 500 and the circuit. Through the coordinated operation of the driver chip U2 and the freewheeling module 201, the constant current drive module 200 can provide a stable and reliable constant current drive for the LED module 500, ensuring that the LED maintains stable brightness output and a long service life under various operating conditions.

[0057] See Figure 4 In this embodiment, the freewheeling module 201 includes an inductor L1 and a switch Q1. One end of the inductor L1 is electrically connected to the power supply, and the other end is electrically connected to the LED module 500. The source of the switch Q1 is electrically connected to the other end of the inductor L1, the drain of the switch Q1 is grounded, and the gate of the switch Q1 is electrically connected to the control terminal of the driver chip U2.

[0058] In this embodiment, the freewheeling module 201 adopts a buck topology, achieving precise control of the LED current through the cooperation of inductor L1 and switching transistor Q1. Inductor L1, acting as an energy storage element and current smoothing device, is connected at one end to the power supply from the boost module 100 and at the other end to the LED module 500, playing a crucial role in maintaining current continuity and filtering throughout the circuit. The inductance value of inductor L1 is typically selected within the range of 10μH-1mH, optimized according to switching frequency, output current, and ripple requirements.

[0059] The switching transistor Q1 can be an N-channel MOSFET, which features low on-resistance, fast switching characteristics, and good power handling capability. The source of the switching transistor Q1 is connected to the other end of the inductor L1, forming a current detection and control node; the drain is grounded, providing a current loop; the gate is connected to the control terminal of the driver chip U2, receiving the PWM control signal. When the driver chip U2 outputs a high-level PWM signal, the switching transistor Q1 is turned on, and current flows from the power supply through the inductor L1 to the LED module 500, while the inductor L1 stores magnetic field energy. When the PWM signal is low, the switching transistor Q1 is turned off, and the magnetic field energy stored in the inductor L1 continues to provide current to the LED through the freewheeling diode (usually integrated in the circuit or a parasitic diode of the LED module 500), achieving continuous current output.

[0060] By adjusting the duty cycle of the PWM signal, the average current flowing through the LED module 500 can be precisely controlled, achieving constant current drive. The presence of inductor L1 smooths the LED current change, avoiding current spikes and ripples caused by switching actions, ensuring the LED receives a stable operating current, improving luminous efficacy stability, and extending lifespan. Furthermore, this topology offers advantages such as high efficiency, low heat loss, and low electromagnetic interference, making it suitable for LED driver applications of various power levels.

[0061] See Figure 1 In this embodiment, an external boost control module 400 is also included. The external boost control module 400 includes a third connection terminal B3, a fourth connection terminal B4 and a fifth connection terminal B5. The third connection terminal B3 is electrically connected to the power supply, the fourth connection terminal B4 is electrically connected to the constant current drive module 200, and the fifth connection terminal B5 is electrically connected to the LED module 500.

[0062] The external boost control module 400 is mainly used to provide a higher operating voltage to the constant current drive module 200, solving the problem that the constant current drive module 200 cannot work properly under low power supply voltage or high voltage LED load conditions. This module is essentially a pre-amplifier boost power supply for the constant current drive module 200, ensuring that the constant current drive module 200 always operates within the optimal voltage range.

[0063] In this embodiment, the external boost control module 400 can adopt a boost converter topology. It receives the input voltage (e.g., 5V) from the power supply through the third connection terminal B3, and after processing by the internal boost circuit, provides a higher operating voltage (e.g., 12V-15V) to the constant current drive module 200 through the fourth connection terminal B4. The fifth connection terminal B5 connects to the LED module 500 and is mainly used for feedback detection of voltage and load status, so that the boost control module can dynamically adjust the output voltage according to the LED load.

[0064] This module internally contains a boost switching power supply circuit, consisting of a PWM controller, a power switching transistor Q1, a boost inductor L1, a freewheeling diode, and an output filter capacitor. The PWM controller dynamically adjusts the duty cycle of the switching transistor Q1 based on output voltage feedback and load changes to achieve stable boost output. When the LED load is heavy or requires a higher drive voltage, the controller automatically increases the duty cycle to increase the output voltage; when the load is light, it correspondingly decreases the duty cycle to improve efficiency.

[0065] The external boost control module 400 provides sufficient operating voltage to the constant current drive module 200, ensuring its stable operation under various load conditions. Especially when driving multiple LEDs connected in series or high-power LEDs, the constant current drive module 200 requires a higher operating voltage to maintain constant current output; in this case, the external boost control module 400 plays a crucial role. This module also features overvoltage protection, overcurrent protection, and short-circuit protection. When abnormal conditions are detected, it can promptly shut down the output to protect the entire drive circuit.

[0066] With the assistance of an external boost control module 400, the entire LED driver system can adapt to a wider input voltage range and more diverse LED load types, improving the system's versatility and reliability. This design is particularly suitable for applications requiring the driving of high-voltage LEDs or multiple strings of LEDs, effectively solving the problem of insufficient voltage margin in a single constant current driver module 200.

[0067] The present invention further proposes a controller including an LED driving circuit. The specific structure of the LED driving circuit is as described in the above embodiments. Since the present controller adopts all the technical solutions of all the above embodiments, it has at least all the technical effects brought about by the technical solutions of the above embodiments, which will not be described in detail here.

[0068] In this embodiment, the controller adopts an integrated design, integrating all functional modules of the LED driver circuit into a unified controller housing to form a complete LED driver control unit. The controller includes external interfaces such as a power input interface, an LED output interface, and a control signal interface, facilitating connection to external power supplies, LED loads, and host computer control systems. Internally, the controller integrates a boost module 100, a constant current drive module 200, a main control module 300, and an external boost control module 400. These modules are electrically connected through internal circuit board wiring, forming a complete LED driver control system.

[0069] The controller features a wide input voltage range (2.5V-12V), multiple current output options (50mA-3A), PWM dimming control, and overvoltage and overcurrent protection. It supports various LED load types, including single high-power LEDs, multi-series LED arrays, and LED strips. Through its internal intelligent identification circuitry, it automatically adjusts operating parameters to achieve optimal driving performance without external configuration.

[0070] The controller can also be equipped with a standardized communication interface, supporting I2C, SPI, or UART communication protocols, enabling data exchange with microcontrollers, smart home systems, or industrial control systems to achieve advanced functions such as remote control, status monitoring, and fault diagnosis. Furthermore, the controller features small size, light weight, and excellent heat dissipation, making it suitable for various space-constrained applications, such as portable lighting equipment, automotive lights, and industrial equipment indicator lights.

[0071] This invention further proposes an LED lighting device, including the controller described in the foregoing embodiment.

[0072] In this embodiment, the LED lighting device can be composed of a controller, an LED light source module, a heat dissipation structure, an optical system, and a housing structure. The controller adopts the technical solution of the aforementioned embodiment, integrating functional units such as a boost module 100, a constant current drive module 200, and a main control module 300, providing a stable and reliable driving power supply for the LED light source module. The LED light source module includes one or more LED chips, and LED devices with different power levels and color temperature specifications can be selected according to lighting requirements.

[0073] This LED lighting device effectively solves the technical challenges of traditional LED lighting products in areas such as low-voltage start-up, constant current drive, and intelligent control by integrating all the technical advantages of the aforementioned controller.

[0074] The above description is only a part or preferred embodiment of this utility model. Neither the text nor the drawings should limit the scope of protection of this utility model. All equivalent structural transformations made using the content of this utility model specification and drawings under the overall concept of this utility model, or direct / indirect applications in other related technical fields, are included within the scope of protection of this utility model.

Claims

1. An LED driving circuit, characterized by, include: The boost module includes a power input terminal and a boost output terminal, wherein the power input terminal is electrically connected to a power source; The constant current drive module includes a first connection terminal and a second connection terminal. The first connection terminal is electrically connected to the boost output terminal, and the second connection terminal is electrically connected to the LED module. The boost module is used to boost the input voltage to the operating voltage required by the constant current drive module when the input voltage at the power input terminal is lower than the start-up threshold. The main control module is electrically connected to the constant current drive module and is configured to output control signals to the constant current drive module to control the operation of the constant current drive module.

2. The LED driving circuit according to claim 1, characterized in that, The boost module includes a boost chip, which has a first pin and a second pin. The first pin is electrically connected to the power input terminal, and the second pin is electrically connected to the boost output terminal.

3. The LED driving circuit according to claim 2, characterized in that, The boost module further includes a first filter capacitor and a second filter capacitor. One end of the first filter capacitor is electrically connected to the first pin, and the other end is grounded. One end of the second filter capacitor is electrically connected to the second pin, and the other end is grounded.

4. The LED driving circuit of claim 2, wherein, The boost module also includes a flying capacitor, and the boost chip also includes a positive connection terminal and a negative connection terminal. One end of the flying capacitor is electrically connected to the positive connection terminal, and the other end is electrically connected to the negative connection terminal.

5. The LED driving circuit of claim 1, wherein, The boost module is a voltage multiplier charge pump, which includes a clock unit and a voltage multiplier unit. The clock unit includes a first input terminal, a first output terminal, and a signal output terminal. The first input terminal is electrically connected to the power input terminal. The voltage multiplier unit includes a second input terminal, a signal receiving terminal, and a second output terminal. The second input terminal is electrically connected to the first output terminal, the signal receiving terminal is electrically connected to the signal output terminal, and the second output terminal is electrically connected to the first connection terminal.

6. The LED driving circuit of claim 1, wherein, The constant current driving module includes a driving chip and a freewheeling module electrically connected between the power supply and the LED module. The control terminal of the driving chip is electrically connected to the control terminal of the freewheeling module.

7. The LED driving circuit of claim 6, wherein, The freewheeling module includes an inductor and a switching transistor. One end of the inductor is electrically connected to a power supply, and the other end is electrically connected to the LED module. The source of the switching transistor is electrically connected to the other end of the inductor, the drain of the switching transistor is grounded, and the gate of the switching transistor is electrically connected to the control terminal of the driver chip.

8. The LED driving circuit of claim 5, wherein, It also includes an external boost control module, which includes a third connection terminal, a fourth connection terminal and a fifth connection terminal. The third connection terminal is electrically connected to the power supply, the fourth connection terminal is electrically connected to the constant current drive module, and the fifth connection terminal is electrically connected to the LED module.

9. A controller characterized by comprising: Includes the LED driving circuit according to any one of claims 1 to 8.

10. An LED lighting device, characterized by Includes the controller as described in claim 9.

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