Light source driving circuit, method and device and light source equipment

Abstract

The invention discloses a light source driving circuit, a light source driving method, a light source driving device and light source equipment. The constant-current driving module comprises at least two paths of constant-current driving circuits which are connected in parallel, and is connected with the input end of the LED module so as to provide driving current for the LED module; the power supply circuit is connected with the input end of the constant-current driving module and is used for dynamically adjusting the input voltage of the constant-current driving module, so that the current ripple corresponding to the current driving current is lower than a preset threshold value; and the control circuit is used for calibrating power supply circuit parameters corresponding to different driving currents so as to extract the power supply circuit parameters corresponding to the adjusting instruction of the current driving current to control the power supply circuit to complete configuration. The technical contradiction that the three key performance indexes of large current output, low current ripple and fast stroboflash are difficult to reconcile is effectively solved, unification of large current driving and extremely low ripple is achieved on the premise that the response speed is not sacrificed, and the increasingly-improved performance requirement of high-end machine vision is met.

Description

Technical Field

[0001] This invention belongs to the field of machine vision, and particularly relates to a light source driving circuit, method, device and light source equipment. Background Technology

[0002] In machine vision systems and industrial inspection, high-brightness, high-uniformity light sources are key components for achieving high-precision image acquisition. Line scan cameras are typically used in conjunction with motion platforms to scan and image objects during continuous movement. This application scenario places extremely stringent requirements on the light source: on the one hand, the motion platform's speed limits the line scan camera's exposure time, resulting in extremely short exposure times. Therefore, the light source needs to possess high brightness to achieve sufficient grayscale values ​​in the sample image within a short exposure time to ensure analytical quality. On the other hand, to match high-speed motion and acquisition frequency, the light source must support rapid flicker and zoned illumination control. LEDs, due to their long lifespan, fast response, and ease of adjustment, have become the preferred light source for machine vision. However, traditional LED driving solutions face significant technical bottlenecks in simultaneously meeting the requirements of high current, low ripple, and rapid flicker.

[0003] In existing technologies, LED drivers mainly employ two architectures: constant current driving and constant voltage driving. While constant voltage driving schemes are simple in structure, they cannot achieve rapid on / off control, and directly connecting the MOSFET to ground in parallel can lead to short-circuit risks, making it difficult to meet high-frequency flicker requirements. In contrast, constant current driving schemes, especially those based on BUCK-type constant current driving circuits, can achieve rapid switching control by connecting a MOSFET in parallel at the output. For example, Chinese invention patent CN117835490A discloses a multi-channel LED driving circuit, driving method, and light source device. This scheme introduces an independent "zero-power MOSFET" connected in parallel with multiple LEDs, using a PWM signal to control the MOSFET's conduction time, aiming to optimize the LED lighting speed and solve the lighting delay and linearity degradation problems caused by traditional PWM dimming. Its core lies in controlling a common ground switch to influence the drive current build-up process, thereby improving response speed. However, such schemes are essentially still optimizations for single-channel or low-current driving scenarios. When the application scenario requires a drive current of 10 amps or even higher, the output capability of a single-channel BUCK constant current drive circuit (usually only a few amps) cannot meet the requirements.

[0004] To increase the total output current, existing technologies have attempted to directly connect the outputs of multiple constant current BUCK circuits in parallel. However, while this simple parallel connection method increases the current output capability, it introduces a significant side effect: excessively high output current ripple. The switching devices in each parallel branch cannot achieve ideal synchronous switching; their switching frequencies and phases exhibit random differences, resulting in a total output current that is not a stable DC current but rather a high-frequency pulsating waveform superimposed with the ripple from each branch. This ripple significantly reduces the stability of the light source. On the other hand, if a constant voltage drive scheme with relatively good ripple characteristics is used, the inherent fast flickering capability of constant current drive is lost, because a constant voltage source cannot directly use parallel MOSFETs to ground for fast switching, otherwise it will cause an output short circuit.

[0005] Therefore, under the existing technological framework, the three key performance indicators of high current output, low current ripple and fast flicker have formed an intractable technical contradiction. The industry urgently needs an innovative drive architecture that can break through the above limitations and achieve the unity of high current drive and extremely low ripple without sacrificing response speed, so as to meet the ever-increasing performance requirements of high-end machine vision.

[0006] Therefore, in order to solve the above problems, the present invention provides a light source driving circuit, method, apparatus and light source device. Summary of the Invention

[0007] The purpose of this invention is to overcome the above-mentioned problems existing in the prior art and to provide a light source driving circuit, method, device and light source equipment, which achieves low ripple output and fast flicker control under high current drive by parallel connection of multiple constant current driving circuits and dynamic voltage adjustment.

[0008] To achieve the above-mentioned technical objectives and effects, the present invention is implemented through the following technical solution: A light source driving circuit for reducing the ripple of the driving current includes: The LED module includes at least two parallel LED circuits, each consisting of a series NMOS transistor and a string of LEDs. The constant current drive module includes at least two parallel constant current drive circuits connected to the input terminal of the LED module to provide drive current for the LED module. The power supply circuit is connected to the input terminal of the constant current drive module and is used to dynamically adjust the input voltage of the constant current drive module so that the current ripple corresponding to the current drive current is lower than the preset threshold. The control circuit is connected to the LED module, constant current drive module, and power supply circuit respectively. It is used to calibrate the power supply circuit parameters corresponding to different drive currents, thereby extracting the power supply circuit parameters corresponding to the current drive current adjustment command, so as to control the power supply circuit to complete the configuration.

[0009] Furthermore, it also includes: a grounding switch, which is an NMOS transistor structure, with its drain connected in parallel with the LED module, its source grounded, and its gate connected to the control circuit.

[0010] Furthermore, in the LED circuit, the drain of the NMOS transistor is connected to the cathode of the LED string, the source is grounded, and the gate is connected to the control circuit.

[0011] Furthermore, the constant current drive circuit is a BUCK-type constant current drive circuit.

[0012] Furthermore, the input voltage of the constant current drive module satisfies the following formula: ;in, ; In the formula, V in V is the input voltage of the constant current drive circuit. out The output voltage of the constant current drive circuit is ΔI. L f is the current ripple on inductor L. sw Where L is the switching frequency of the constant current drive circuit, L is the inductance, and D is the duty cycle of the constant current drive circuit.

[0013] The present invention also provides a light source driving method for reducing the ripple of the driving current, the driving method comprising: Connect at least two constant current drive circuits in parallel to increase the drive current of the LED module; The drive current is divided into different levels, and the current ripple corresponding to the drive current at each level is measured. Adjust the power supply circuit parameters so that the current ripple corresponding to the drive current at the current gear is lower than the preset threshold, thereby calibrating the power supply circuit parameters corresponding to the drive current at different gears. Extract the power supply circuit parameters corresponding to the current drive current adjustment command so that the power supply circuit can complete the configuration; The LED module includes at least two parallel LED circuits, each consisting of a series NMOS transistor and a string of LEDs.

[0014] Furthermore, adjusting the power supply circuit parameters to ensure that the current ripple corresponding to the drive current at the current gear is below a preset threshold includes: Adjust the power supply circuit parameters so that the input voltage of the constant current drive module is greater than the turn-on voltage of the LED module; Determine whether the current ripple corresponding to the drive current in the current gear is lower than the preset threshold: if yes, save the corresponding power supply circuit parameters; if no, adjust the power supply circuit parameters to reduce the input voltage of the constant current drive module. Repeat the above operation until the current ripple corresponding to the drive current in the current gear is lower than the preset threshold.

[0015] Furthermore, the method for analyzing the on-state voltage of the LED module includes: A mapping model is constructed between the on-state voltage of the LED module and the driving current and temperature at the current gear. The on-state voltage of the corresponding LED module at different gears and different temperatures is collected to fit the parameters of the mapping model.

[0016] The present invention also provides a light source driving device, comprising: As described in the above driving circuit; The memory is used to store the power supply circuit parameters corresponding to different drive current calibrations.

[0017] The present invention also provides a light source device, comprising: As described in the above driving circuit; The device interface is used to receive external trigger signals to control the corresponding NMOS transistor in the LED circuit to turn on according to the external trigger signals.

[0018] The beneficial effects of this invention are: (1) This invention effectively solves the technical contradiction of the three key performance indicators of high current output, low current ripple and fast flicker, which are difficult to reconcile. Without sacrificing response speed, it achieves the unity of high current drive and extremely low ripple, meeting the ever-increasing performance requirements of high-end machine vision. Specifically, this invention innovates the topology structure of parallel multi-channel constant current drive circuits, superimposing the limited driving capabilities of a single channel to easily achieve high current output and meet the requirements of high-brightness lighting. More importantly, this invention creatively introduces a dynamic adjustment mechanism for the power supply voltage. By controlling the circuit to optimize the input voltage of the constant current drive circuit in real time, making it close to the output voltage, the duty cycle of the BUCK circuit is pushed to the ideal state, suppressing the inherent ripple superposition effect of multiple parallel circuits from the root and controlling the ripple current at an extremely low level. At the same time, the LED module design based on the NMOS transistor switching array ensures the flicker response speed, perfectly matching the exposure requirements of high-speed cameras.

[0019] (2) In the driving method of the present invention, firstly, by connecting at least two constant current driving circuits in parallel, the total output current can achieve linear growth, which solves the technical bottleneck of high current output; then, by dividing the driving current into different levels and measuring the current ripple under different levels, the actual performance of the system at each working point can be accurately obtained, providing a data basis for subsequent parameter optimization; by adjusting the power supply circuit parameters so that the current ripple corresponding to the driving current under the current level is lower than the preset threshold, the input voltage of the constant current driving module is optimized in real time, so that it accurately tracks the change of output voltage; by calibrating to obtain the power supply circuit parameters corresponding to different levels, the system can quickly call the pre-optimized configuration parameters in actual work, which not only ensures optimal performance, but also greatly reduces the dependence on component accuracy and improves production yield; by extracting the power supply parameters corresponding to the current driving current and completing the configuration, the system can complete parameter extraction and circuit configuration in a very short time after receiving the current adjustment command, ensuring the rapid stabilization of the output current. Attached Figure Description

[0020] The accompanying drawings, which are included to provide a further understanding of the invention and form part of this application, illustrate exemplary embodiments of the invention and, together with their description, serve to explain the invention and do not constitute an undue limitation thereof. In the drawings: Figure 1 This is a schematic diagram of the driving circuit in this invention; Figure 2 This is a flowchart of the driving method in this invention. Detailed Implementation

[0021] The technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0022] In photometric stereo systems, line scan cameras are typically used in conjunction with a motion platform to scan and image objects during continuous movement. Line scan cameras require LED driver circuits to control the illumination and extinguishing of different zones after receiving trigger signals. For example, receiving the first trigger signal illuminates the first zone, the line scan camera begins exposure, and extinguishes the first zone after exposure. Receiving the second trigger signal illuminates the second zone, the line scan camera begins exposure, and extinguishes the second zone after exposure, and so on. After receiving a set of trigger signals, the line scan camera begins transmitting data. During this time, all light sources must be extinguished to reduce unnecessary power consumption until data transmission is complete. After data transmission, the line scan camera begins receiving the second set of trigger signals. On the one hand, the motion platform's speed limits the line scan camera's exposure time, resulting in extremely short exposure times. This necessitates a high-brightness light source to achieve sufficient grayscale values ​​in the sample image within a short exposure time to ensure analytical quality. On the other hand, to match the high-speed movement and acquisition frequency, the light source must support rapid strobe and zone illumination control. While existing technologies disclose single-channel BUCK-type constant current drive circuits for driving multiple LEDs, they are only suitable for low-current driving scenarios. When applications require drive currents of 10 amps or even higher, the output capability of a single-channel BUCK constant current drive circuit (typically only a few amps) is insufficient. To increase the total output current, simply connecting the output terminals of multiple constant current BUCK circuits in parallel, while increasing the current output capability, leads to excessively high output current ripple. Therefore, within the existing technological framework, the three key performance indicators of high current output, low current ripple, and rapid flicker present a difficult-to-reconcile technical contradiction.

[0023] To solve the above problems, such as Figure 1 As shown, this embodiment first provides a light source driving circuit for reducing the ripple of the driving current, including: The LED module includes at least two parallel LED circuits, each consisting of a series-connected NMOS transistor and an LED string. In a specific implementation, the drain of the NMOS transistor in the LED circuit is connected to the cathode of the LED string, the source is grounded, and the gate is connected to the control circuit. The NMOS transistors (N1 to Nn) act as switching devices, and their conduction state is controlled by the gate voltage. When a particular NMOS transistor is turned on, the LED string in that path forms a complete circuit and is illuminated; when it is turned off, that path is extinguished. This structure supports independent control of each LED circuit, enabling zoned lighting.

[0024] The constant current drive module includes at least two parallel constant current drive circuits connected to the input terminal of the LED module to provide drive current for the LED module. In a specific implementation, the constant current drive circuit is a BUCK-type constant current drive circuit, i.e., a BUCK circuit. Multiple BUCK circuits are designed in parallel, connected together through sampling resistors Rsns to provide drive current to the LED module. The parallel structure expands the total output current, meeting the high current drive requirements of the LED module. The BUCK circuit achieves constant current output by controlling the duty cycle of its MOSFET through pulse width modulation (PWM). When the MOSFET is turned on, the inductor stores energy, and the current increases linearly; when turned off, the inductor releases energy through the freewheeling diode, and the current decreases linearly. The current value is detected by the sampling resistor, and the duty cycle is controlled by feedback to maintain a constant output current.

[0025] Single-channel current-driven LED driver circuits often struggle to achieve a drive current in the 10A range. By connecting multiple BUCK circuits in parallel, the output current is increased, thereby enhancing the driving capability of the LEDs and achieving brighter lighting. A single-channel current-driven BUCK circuit controls its full-scale output current via Rsns. The maximum output current I_max_single and Rsns satisfy the following relationship: I_max_single = k / Rsns Where k is a constant. The maximum output current when M channels are connected in parallel is: I_max = M×k / Rsns The BUCK circuit maintains a constant output current through charging and discharging, which is controlled by the switch PGATE to turn it on and off.

[0026] The power supply circuit, connected to the input of the constant current drive module, dynamically adjusts the input voltage of the constant current drive module to ensure that the current ripple corresponding to the current drive current is below a preset threshold. The adjustable power supply circuit provides a stable power supply to the subsequent BUCK circuit and effectively suppresses the current ripple at the output of the BUCK circuit through appropriate voltage regulation.

[0027] The control circuit is connected to the LED module, constant current drive module, and power supply circuit respectively. It is used to calibrate the power supply circuit parameters corresponding to different drive currents, thereby extracting the power supply circuit parameters corresponding to the current drive current adjustment command, so as to control the power supply circuit to complete the configuration.

[0028] To achieve rapid full-zone shutdown, the light source driver circuit also includes a grounding switch, which is an NMOS transistor structure. Figure 1 In the N0 transistor, the drain is connected in parallel with the LED module, the source is grounded, and the gate is connected to the control circuit. When it is necessary to quickly extinguish all LEDs, the control circuit first turns on the ground switch to provide a low-impedance path for the LED current to discharge rapidly. Then, it turns off the NMOS transistors in each LED circuit to avoid voltage spikes.

[0029] To reduce output current ripple, a method for dynamically reducing the input-output voltage difference of the constant current drive circuit (i.e., the BUCK circuit) is proposed based on the above-mentioned light source drive circuit. The principle is as follows: The output current is controlled by turning the MOSFET in the BUCK circuit on and off. When the MOSFET is on, V... in >V out The current through inductor L increases, where V in V is the input voltage of the BUCK circuit. out Let L be the output voltage of the BUCK circuit. When the current exceeds the threshold, the MOSFET in the BUCK circuit is turned off, and the current through the inductor L gradually decreases. Its output current ripple satisfies the following relationship:

[0030] Where, ΔI L The current ripple is on inductor L, D is the duty cycle of the BUCK circuit, and f is the current ripple. sw Where is the switching frequency of the constant current drive circuit, and L is the inductance.

[0031] For constant current driven LED applications, the voltage is fixed, that is, V. out Fixed, in order to reduce current ripple ΔI L This can be achieved by increasing D; ideally, D = V. out / V in For a light source with a characteristic curve of V=f(I), in order to adjust the brightness of the LED string during application, it is necessary to change the output current I0 of the BUCK circuit, and correspondingly the LED circuit voltage V. o It will also change, that is, the V of the drive circuit. out It also changes with the current. By synchronously adjusting the output voltage of the power supply circuit, low ripple can be maintained at various brightness levels (various drive current magnitudes). When the current flowing through the light source is I_n, its voltage across its terminals is V_n. To control the light source current ripple to not exceed ΔI... L Then it is necessary to:

[0032] In theory, when the input voltage of the BUCK circuit is equal to the output voltage, the MOS transistor of the BUCK circuit is always on, and no ripple is introduced due to charge and discharge. The ripple of the light source is determined by the power supply of the previous stage. At this time, the supply voltage of the BUCK circuit is set to V0 = f(I0) according to the current flowing through the light source. At this time, the circuit is equivalent to a voltage-type drive, characterized by small ripple. When the light source turns on and flashes off, the MOS transistor from the light source to the ground closes. At this time, the output current of the BUCK circuit is I0, the supply voltage is V0, but the output voltage becomes V1. The equivalent resistance from the MOS transistor to the ground is much smaller than that of the LED. At this time, V1 < V0. According to the current ripple formula, the ripple becomes larger at this time, but the average current is still I0. Limited by the current-type BUCK circuit, fast on-off flashing of each partition can be achieved.

[0033] The present invention effectively solves the technical contradiction that it is difficult to reconcile the three key performance indicators of high-current output, low-current ripple, and fast flashing. Without sacrificing the response speed, it realizes the unity of high-current drive and extremely low ripple, meeting the increasingly demanding performance requirements of high-end machine vision. Specifically, through the topological structure innovation of parallel connection of multiple constant-current drive circuits, the limited driving capabilities of single circuits are superimposed, easily achieving high-current output and meeting the requirements of high-brightness lighting. More importantly, the present invention creatively introduces a dynamic supply voltage regulation mechanism. By controlling the circuit to optimize the input voltage of the constant-current drive circuit in real time, making it close to the output voltage, the duty cycle of the BUCK circuit is pushed to an ideal state, suppressing the inherent ripple superposition effect of multiple parallel connections at the source, and controlling the ripple current at an extremely low level. At the same time, the design of the LED module based on the NMOS transistor switch array ensures the flashing response speed, perfectly matching the exposure requirements of high-speed cameras.

[0034] The present invention also provides a light source driving method for reducing the ripple of the driving current. The driving method includes: Connecting in parallel at least two constant-current drive circuits to increase the driving current of the LED module. The specific circuit structure can refer to the above-mentioned light source driving circuit. Among them, the LED module includes at least two parallel LED circuits, and each LED circuit consists of a series-connected NMOS transistor and an LED lamp string.

[0035] Dividing the driving current into different gears and respectively measuring the current ripple corresponding to the driving current at different gears.

[0036] The power supply circuit parameters are adjusted to ensure that the current ripple corresponding to the drive current at the current speed is lower than a preset threshold, thereby calibrating the power supply circuit parameters corresponding to the drive current at different speeds. Specifically, this includes: adjusting the power supply circuit parameters so that the input voltage of the constant current drive module is greater than the turn-on voltage of the LED module; determining whether the current ripple corresponding to the drive current at the current speed is lower than the preset threshold: if yes, the corresponding power supply circuit parameters are saved; if not, the power supply circuit parameters are adjusted to reduce the input voltage of the constant current drive module; repeating the above operation until the current ripple corresponding to the drive current at the current speed is lower than the preset threshold.

[0037] Extract the power supply circuit parameters corresponding to the current drive current adjustment command to enable the power supply circuit to complete the configuration.

[0038] like Figure 2 As shown, the entire method is mainly divided into two parts: parameter calibration and parameter adjustment. Different light sources need to be calibrated before use to determine the power supply parameters, and the parameter calibration part completes this task. As a specific implementation of the driving method, it is assumed that the BUCK circuit driving current can be adjusted to N levels, with each level corresponding to a driving current of I... N The corresponding LED voltage is V N First, set it to level 1, and adjust the power supply circuit parameters so that the supply voltage of the BUCK circuit is greater than V. N Configure power supply to be greater than V N A value V N1 Measure I at this time N If the ripple is too large, modify the power supply circuit parameters to configure the voltage to V. N2 (V) N2 <V N1 This process continues until the ripple is small, i.e., below the preset threshold, and the power supply circuit parameters {a1, b1...} are saved. Then, the output current of the BUCK circuit is adjusted to I2, and the above steps are repeated to save the second set of power supply circuit parameters {a2, b2...}. The above operation is repeated for the remaining N-2 current levels, saving a total of N sets of parameters: {a1, b1...}, {a2, b2...}...{aN, bN...}, completing the parameter calibration process.

[0039] After calibration, the calibrated parameters are stored in memory. During operation, the host computer issues a command to adjust the output current of the BUCK circuit to I. M The processor is based on the current I M Retrieve and configure the corresponding set of circuit parameters {aM, bM...} from the memory to adjust the power supply voltage of the BUCK-type constant current drive circuit, and then adjust the drive circuit current to I. M This keeps the drive current ripple at a low level.

[0040] In order to address the aforementioned V N To perform accurate and rapid analysis, the analysis method for the conduction voltage of the LED module includes: A mapping model is constructed between the on-state voltage of the LED module and the driving current and temperature at the current gear. The on-state voltage of the corresponding LED module at different gears and different temperatures is collected to fit the parameters of the mapping model.

[0041] The mapping model between the LED module's on-state voltage and the driving current and temperature at the current gear level is as follows:

[0042] Among them, V N Where I is the forward voltage of the LED module, T is the temperature, and I is the forward voltage. N The current is the drive current at the current gear position. α1, α2, α3, α4, α5, and α6 are fitting parameters used in the calculation. The drive current I at different gear positions is collected. N The on-state voltage V of the LED module at different temperatures T N By obtaining several sets of statistical data, and substituting them into the mapping model, all fitting parameters can be analyzed and obtained.

[0043] In the driving method of this invention, firstly, by connecting at least two constant current driving circuits in parallel, the total output current can achieve linear growth, solving the technical bottleneck of high current output. Then, by dividing the driving current into different levels and measuring the current ripple at each level, the actual performance of the system at each operating point can be accurately obtained, providing a data basis for subsequent parameter optimization. By adjusting the power supply circuit parameters to ensure that the current ripple corresponding to the driving current at the current level is lower than a preset threshold, the input voltage of the constant current driving module is optimized in real time, enabling it to accurately track changes in the output voltage. By calibrating the power supply circuit parameters corresponding to different levels, the system can quickly call the pre-optimized configuration parameters in actual operation, ensuring optimal performance and significantly reducing dependence on component accuracy, thus improving production yield. By extracting the power supply parameters corresponding to the current driving current and completing the configuration, the system can complete parameter extraction and circuit configuration in a very short time after receiving the current adjustment command, ensuring rapid stabilization of the output current.

[0044] The present invention also provides a light source driving device, comprising: As described in the above driving circuit; The memory is used to store the power supply circuit parameters corresponding to different drive current calibrations.

[0045] The present invention also provides a light source device, comprising: As described in the above driving circuit; The device interface is used to receive external trigger signals to control the corresponding NMOS transistor in the LED circuit to turn on according to the external trigger signals.

[0046] The present invention also provides a computer-readable storage medium including a computer program that, when executed by a processor, implements the above-described driving method.

[0047] In practical applications, a computer-readable storage medium can be any combination of one or more computer-readable media. A computer-readable medium can be a computer-readable signal medium or a computer-readable storage medium. A computer-readable storage medium can be, but is not limited to, an electrical, magnetic, optical, electromagnetic, infrared, or semiconductor system, apparatus, or device, or any combination thereof. More specific examples of a computer-readable storage medium may include: an electrical connection having one or more wires, a portable computer disk, a hard disk, random access memory (RAM), read-only memory (ROM), erasable programmable read-only memory (EPROM or flash memory), optical fiber, portable compact disk read-only memory (CD-ROM), optical storage device, magnetic storage device, or any suitable combination thereof. In this embodiment, a computer-readable storage medium can be any tangible medium containing or storing a program that can be used by or in conjunction with an instruction execution system, apparatus, or device.

[0048] Computer-readable signal media may include data signals propagated in baseband or as part of a carrier wave, carrying computer-readable program code. Such propagated data signals may take various forms, including but not limited to electromagnetic signals, optical signals, or any suitable combination thereof. Computer-readable signal media may also be any computer-readable medium other than computer-readable storage media, capable of sending, propagating, or transmitting programs for use by or in connection with an instruction execution system, apparatus, or device.

[0049] Program code contained on a computer-readable medium may be transmitted using any suitable medium, including but not limited to wireless, wire, optical fiber, RF, etc., or any suitable combination thereof.

[0050] Computer program code for performing the operations of this application can be written in one or more programming languages ​​or a combination thereof, including object-oriented programming languages ​​such as Java, Smalltalk, and C++, and conventional procedural programming languages ​​such as the "C" language or similar programming languages. The program code can be executed entirely on the user's computer, partially on the user's computer, as a standalone software package, partially on the user's computer and partially on a remote computer, or entirely on a remote computer or server. In cases involving remote computers, the remote computer can be connected to the user's computer via any type of network—including a local area network (LAN) or a wide area network (WAN)—or can be connected to an external computer (e.g., via the Internet using an Internet service provider).

[0051] In the description of this specification, references to terms such as "an embodiment," "example," and "specific example" indicate that a specific feature, structure, material, or characteristic described in connection with that embodiment or example is included in at least one embodiment or example of the invention. In this specification, illustrative expressions of the above terms do not necessarily refer to the same embodiment or example. Furthermore, the specific features, structures, materials, or characteristics described may be combined in any suitable manner in one or more embodiments or examples.

[0052] The foregoing has shown and described the basic principles, main features, and advantages of the present invention. Those skilled in the art should understand that the present invention is not limited to the above embodiments. The embodiments and descriptions in the specification are merely illustrative of the principles of the invention. Various changes and modifications can be made to the invention without departing from its spirit and scope, and all such changes and modifications fall within the scope of the claimed invention.

Claims

1. A light source driving circuit for reducing the ripple of the driving current, characterized in that, include: The LED module includes at least two parallel LED circuits, each consisting of a series NMOS transistor and a string of LEDs. The constant current drive module includes at least two parallel constant current drive circuits connected to the input terminal of the LED module to provide drive current for the LED module. The power supply circuit is connected to the input terminal of the constant current drive module and is used to dynamically adjust the input voltage of the constant current drive module so that the current ripple corresponding to the current drive current is lower than the preset threshold. The control circuit is connected to the LED module, constant current drive module, and power supply circuit respectively. It is used to calibrate the power supply circuit parameters corresponding to different drive currents, thereby extracting the power supply circuit parameters corresponding to the current drive current adjustment command, so as to control the power supply circuit to complete the configuration.

2. The light source driving circuit according to claim 1, characterized in that, Also includes: The grounding switch is an NMOS transistor structure, with its drain connected in parallel with the LED module, its source grounded, and its gate connected to the control circuit.

3. The light source driving circuit according to claim 2, characterized in that, In an LED circuit, the drain of an NMOS transistor is connected to the cathode of the LED string, the source is grounded, and the gate is connected to the control circuit.

4. The light source driving circuit according to claim 1, characterized in that, The constant current drive circuit is a BUCK-type constant current drive circuit.

5. A light source driving circuit according to any one of claims 1-4, characterized in that, The input voltage of the constant current drive module satisfies the following formula: ;in, ; In the formula, V in V is the input voltage of the constant current drive circuit. out The output voltage of the constant current drive circuit is ΔI. L f is the current ripple on inductor L. sw Where L is the switching frequency of the constant current drive circuit, L is the inductance, and D is the duty cycle of the constant current drive circuit.

6. A light source driving method for reducing the ripple of the driving current, characterized in that, The driving methods include: Connect at least two constant current drive circuits in parallel to increase the drive current of the LED module; The drive current is divided into different levels, and the current ripple corresponding to the drive current at each level is measured. Adjust the power supply circuit parameters so that the current ripple corresponding to the drive current at the current gear is lower than the preset threshold, thereby calibrating the power supply circuit parameters corresponding to the drive current at different gears. Extract the power supply circuit parameters corresponding to the current drive current adjustment command so that the power supply circuit can complete the configuration; The LED module includes at least two parallel LED circuits, each consisting of a series NMOS transistor and a string of LEDs.

7. A light source driving method according to claim 6, characterized in that, Adjusting the power supply circuit parameters to ensure that the current ripple corresponding to the drive current at the current gear is lower than a preset threshold includes: Adjust the power supply circuit parameters so that the input voltage of the constant current drive module is greater than the turn-on voltage of the LED module; Determine whether the current ripple corresponding to the drive current in the current gear is lower than the preset threshold: if yes, save the corresponding power supply circuit parameters; if no, adjust the power supply circuit parameters to reduce the input voltage of the constant current drive module. Repeat the above operation until the current ripple corresponding to the drive current in the current gear is lower than the preset threshold.

8. The light source driving method according to claim 7, characterized in that, The analysis method for the on-state voltage of the LED module includes: A mapping model is constructed between the on-state voltage of the LED module and the driving current and temperature at the current gear. The on-state voltage of the corresponding LED module at different gears and different temperatures is collected to fit the parameters of the mapping model.

9. A light source driving device, characterized in that, include: The driving circuit as described in any one of claims 1-5; The memory is used to store the power supply circuit parameters corresponding to different drive current calibrations.

10. A light source device, characterized in that, include: The driving circuit as described in any one of claims 1-5; The device interface is used to receive external trigger signals to control the corresponding NMOS transistor in the LED circuit to turn on according to the external trigger signals.

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