Light source driving circuit

Abstract

The invention provides a light source driving circuit, and relates to the technical field of driving. The power input end of the pulse driving circuit is connected with the power output end of the power circuit, the output end of the pulse driving circuit is electrically connected with the light-emitting part, and the pulse driving circuit is used for outputting a pulse signal to drive the light-emitting part to work; the input end of the feedback circuit is connected with the output end of the pulse driving circuit, and the feedback circuit is used for receiving the current signal output by the pulse driving circuit and outputting a corresponding feedback signal to the feedback end of the power supply circuit according to the current signal, so that the power supply circuit adjusts the output current according to the current signal. Stable on-off control of the light-emitting part can be achieved, damage to the light-emitting part caused by current fluctuation is avoided, and therefore the source driving circuit can keep the output current constant when the load changes, and the brightness stability of the light-emitting part and the service life of the device are ensured.

Description

Technical Field

[0001] This application relates to the field of driving technology, and particularly to a light source driving circuit. Background Art

[0002] A light source driving circuit is mainly used to drive a light-emitting element, such as an LED lamp, to achieve lighting or other related functions. To ensure that the lifespan and stability of the device are not affected, the precision and stability of the current must be maintained when driving the light-emitting element. However, the current light source driving circuit has defects in current regulation and is difficult to ensure the constancy of the output current when the load changes, which leads to the instability of the brightness of the light-emitting element and may accelerate the degradation of the device. Summary of the Invention

[0003] The main purpose of the present invention is to provide a light source driving circuit, aiming to ensure the constancy of the output current of the light source driving circuit when the load changes, and improve the brightness stability of the light-emitting component and the lifespan of the device.

[0004] To achieve the above purpose, the present invention provides a light source driving circuit, which is applied to a light source assembly. The light source assembly includes at least one light-emitting component, and at least one of the light-emitting components is electrically connected to the output end of the light source driving circuit. The light source driving circuit includes: A power supply circuit; A pulse driving circuit, the power input end of the pulse driving circuit is connected to the power output end of the power supply circuit, and the output end of the pulse driving circuit is electrically connected to the light-emitting component. The pulse driving circuit is used to output a pulse signal to drive the light-emitting component to work; A feedback circuit, the input end of the feedback circuit is connected to the output end of the pulse driving circuit. The feedback circuit is used to receive the current signal output by the pulse driving circuit and output a corresponding feedback signal to the feedback end of the power supply circuit according to the current signal, so that the power supply circuit adjusts the output current according to the current signal.

[0005] Optionally, when the current signal exceeds the first preset voltage threshold, the feedback circuit outputs a feedback signal for reducing the output current to the feedback end of the power supply circuit to reduce the current output by the power supply circuit; When the current signal is lower than the second preset voltage threshold, the feedback circuit outputs a feedback signal for increasing the output current to the feedback end of the power supply circuit to increase the current output by the power supply circuit.

[0006] Optionally, the feedback circuit includes: A first voltage dividing circuit, the first end of the first voltage dividing circuit is connected to the power output end of the power supply circuit, and the output end of the first voltage dividing circuit is connected to the feedback end of the power supply circuit; A first resistor circuit, a first end of the first resistor circuit is connected to a second end of the first voltage dividing circuit, the first end of the first resistor circuit is connected to an output end of the pulse driving circuit, and a second end of the first resistor circuit is grounded.

[0007] Optionally, the first voltage dividing circuit includes: A first resistor, a first end of the first resistor is connected to a power output end of the power supply circuit; A second resistor, a first end of the second resistor is connected to a second end of the first resistor, a second end of the second resistor is connected to a first end of the first resistor circuit, and a common node of the second resistor and the first resistor is connected to a feedback end of the power supply circuit; The first resistor circuit includes: A third resistor, a first end of the third resistor is respectively connected to a second end of the first voltage dividing circuit and an output end of the pulse driving circuit, and a second end of the third resistor is grounded; A fourth resistor, a first end of the fourth resistor is respectively connected to a second end of the first voltage dividing circuit and an output end of the pulse driving circuit, and a second end of the fourth resistor is grounded.

[0008] Optionally, the power supply circuit includes: A power supply chip, a power input end of the power supply chip is used for accessing an external power supply; A fifth resistor, a second end of the fifth resistor is connected to an enable end of the power supply chip; A first capacitor, a first end of the first capacitor is connected to a bootstrap end of the power supply chip, and a second end of the first capacitor is connected to a switch end of the power supply chip; A first inductor, a first end of the first inductor is connected to a switch end of the power supply chip, and a second end of the first inductor is an output end of the power supply circuit.

[0009] Optionally, the pulse driving circuit includes: A switching tube, a first conducting end of the switching tube is connected to a negative electrode of the light emitting element, and a second conducting end of the switching tube is connected to an input end of the feedback circuit; A sixth resistor, a second end of the sixth resistor is connected to a controlled end of the switching tube.

[0010] Optionally, the light source driving circuit further includes: A driving control circuit, a power input end of the driving control circuit is connected to an output end of the power supply circuit, and an output end of the driving control circuit is connected to a controlled end of the pulse driving circuit.

[0011] Optionally, the driving control circuit includes: A control chip, the control signal output terminal of the control chip is connected to the sixth resistor; A seventh resistor, the first end of the seventh resistor is connected to the output terminal of the power supply circuit, and the second end of the seventh resistor is connected to the power input terminal of the control chip.

[0012] Optionally, the light source driving circuit further includes: A light source protection circuit, the light source protection circuit is electrically connected to the light emitting component, and the light source protection circuit is used to quickly conduct the spike current when the pulse driving circuit is impacted by a current spike.

[0013] Optionally, the light source protection circuit includes: A first diode, the negative electrode of the first diode is connected to the positive electrode of the light emitting component, and the positive electrode of the first diode is connected to the negative electrode of the light emitting component; A bidirectional diode, the first end of the bidirectional diode is connected to the negative electrode of the light emitting component, and the second end of the bidirectional diode is grounded; A buffer capacitor, the first end of the buffer capacitor is connected to the positive electrode of the light emitting component, and the second end of the buffer capacitor is connected to the negative electrode of the light emitting component.

[0014] The light source driving circuit of the embodiment of the present invention is applied to a light source assembly, and the light source assembly includes at least one light emitting component. At least one light emitting component is electrically connected to the output terminal of the light source driving circuit, so that at least one light emitting component is turned on and off under the drive of the light source driving circuit. In order to better realize the on-off drive control of the light emitting component, the light source driving circuit is provided with a power supply circuit, a pulse driving circuit and a feedback circuit. Among them, the power input terminal of the pulse driving circuit is connected to the power output terminal of the power supply circuit, the output terminal of the pulse driving circuit is electrically connected to the light emitting component, the input terminal of the feedback circuit is connected to the output terminal of the pulse driving circuit, and the pulse driving circuit outputs a pulse signal to drive the light emitting component to work. Then, the feedback circuit receives the current signal output by the pulse driving circuit and outputs a corresponding feedback signal to the feedback terminal of the power supply circuit according to the current signal, so that the power supply circuit adjusts the output current according to the current signal, can realize the stable on-off control of the light emitting component, avoid the damage caused by current fluctuation to the light emitting component, and thus can make the power driving circuit maintain a constant output current when the load changes, ensuring the brightness stability of the light emitting component and the service life of the device. Description of the Drawings

[0015] The drawings here are incorporated into the specification and form a part of this specification, showing embodiments consistent with the present application, and are used together with the specification to explain the principles of the present application.

[0016] To more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the following will briefly introduce the drawings required for use in the description of the embodiments or the prior art. Obviously, the drawings in the following description are only some embodiments of the present invention. For those of ordinary skill in the art, without creative efforts, other drawings can be obtained based on these drawings.

[0017] Figure 1 It is a schematic flowchart of a light source driving circuit according to an embodiment of the present invention; Figure 2 It is a schematic flowchart of a light source driving circuit according to another embodiment of the present invention; Figure 3 It is a schematic flowchart of a light source driving circuit according to still another embodiment of the present invention; Figure 4 It is a schematic flowchart of a light source driving circuit according to yet another embodiment of the present invention; Figure 5 It is a schematic flowchart of a light source driving circuit according to still yet another embodiment of the present invention; Figure 6 It is a schematic flowchart of a light source driving circuit according to another embodiment of the present invention; Figure 7 It is a schematic flowchart of a light source driving circuit according to still another embodiment of the present invention; Figure 8 It is a schematic flowchart of a light source driving circuit according to yet another embodiment of the present invention; Figure 9 It is a schematic flowchart of a light source driving circuit according to still yet another embodiment of the present invention; Figure 10 It is a schematic diagram comparing the heat generation and output current ratio of the pulse driving method and the constant current driving method.

[0018] Explanation of the reference numerals in the drawings:

[0019] The realization of the object of the present invention, functional features and advantages will be further described in conjunction with the embodiments and with reference to the drawings. Detailed implementation manners

[0020] The following will clearly and completely describe the technical solutions in the embodiments of the present invention in conjunction with the drawings in the embodiments of the present invention. Obviously, the described embodiments are only some embodiments of the present invention, rather than all embodiments. Well-known modules, units and their connections, links, communications or operations therebetween are not shown or not described in detail. And the described features, architectures or functions can be combined in any way in one or more embodiments. Those skilled in the art should understand that the following various embodiments are only for illustration purposes and are not used to limit the protection scope of the present invention.

[0021] In the prior art, a light source driving circuit is mainly used to drive a light-emitting element, such as an LED lamp, to achieve lighting or other related functions. To ensure that the lifespan and stability of the device are not affected, the precision and stability of the current must be maintained when driving the light-emitting element. Currently, the light source driving circuits on the market often adopt two methods: constant current source or pulse driving.

[0022] Among them, in the method of driving by a constant current source, the heat generation is huge, resulting in a high heat dissipation cost, and the high temperature will also cause the light-emitting efficiency of the light source to decrease. Therefore, the constant current source driving can only be used for small current driving. In the scenario where large current driving is required, pulse driving becomes a more suitable choice.

[0023] However, there are two options for the traditional pulse driving method. One is with feedback, and the other is without feedback. Although the pulse driving method without feedback has a simple circuit, when the load changes, it cannot ensure the constancy of the output current, which will lead to unstable brightness of the light source and may accelerate the degradation of the device. In severe cases, it may even damage the light source. The pulse driving method with feedback can monitor the output current in real time through a feedback circuit and adjust the output current of the power supply circuit according to the current signal, so as to ensure the constancy of the output current. However, the feedback devices in the prior art often use devices such as error amplifiers to achieve this. These devices not only increase the complexity of the circuit but also increase the cost.

[0024] The main solution of the embodiment of the present application is: applying the light source driving circuit to a light source component, and the light source component includes at least one light-emitting element. At least one light-emitting element is electrically connected to the output end of the light source driving circuit, so that at least one light-emitting element is turned on and off under the drive of the light source driving circuit. In order to better realize the on-off drive control of the light-emitting element, the light source driving circuit is provided with a power supply circuit, a pulse driving circuit, and a feedback circuit. Among them, the power input end of the pulse driving circuit is connected to the power output end of the power supply circuit, the output end of the pulse driving circuit is electrically connected to the light-emitting element, the input end of the feedback circuit is connected to the output end of the pulse driving circuit, and the pulse driving circuit outputs a pulse signal to drive the light-emitting element to work. Then, the feedback circuit receives the current signal output by the pulse driving circuit and outputs a corresponding feedback signal to the feedback end of the power supply circuit, so that the power supply circuit adjusts the output current according to the current signal.

[0025] The present application provides a solution that can realize the stable on-off control of the light-emitting element, avoid the damage caused by current fluctuations to the light-emitting element, so that the source driving circuit can maintain the constancy of the output current when the load changes, and ensure the brightness stability of the light-emitting element and the lifespan of the device.

[0026] It should be understood that the light source driving circuit of this embodiment is applied to a light source assembly, which includes at least one light emitting element. Among them, at least one light emitting element is electrically connected to the light source driving circuit so that at least one light emitting element can be turned on and off under the drive of the light source driving circuit.

[0027] The light source assembly can be a light source module in a projector, or a light source part in a car headlight, a street lamp or any device that requires stable light source control. In practical applications, the light emitting element can be an LED lamp bead, a laser diode or other types of light emitting elements. Through the drive of the light source driving circuit, it can be ensured that these light emitting elements are stably turned on and off when receiving the correct pulse signal, which not only improves the stability and brightness uniformity of the light source, but also significantly extends the service life of the light emitting elements.

[0028] Among them, referring to Figure 1 , in an embodiment of the present invention, the light source driving circuit includes a power supply circuit 20, a pulse driving circuit 30 and a feedback circuit 40, where: The power input end of the pulse driving circuit 30 is connected to the power output end of the power supply circuit 20, the output end of the pulse driving circuit 30 is electrically connected to the light emitting element 10, and the pulse driving circuit 30 is used to output a pulse signal to drive the light emitting element 10 to work; the input end of the feedback circuit 40 is connected to the output end of the pulse driving circuit 30, and the feedback circuit 40 is used to receive the current signal output by the pulse driving circuit 30 and output a corresponding feedback signal to the feedback end of the power supply circuit 20 according to the current signal, so that the power supply circuit 20 adjusts the output current according to the current signal.

[0029] The power supply circuit 20 can be a DC power supply or a switching power supply, and its function is to provide a stable power supply voltage to the pulse driving circuit 30. The DC power supply can provide a continuous and stable current, while the switching power supply can dynamically adjust the output voltage according to the load demand to achieve an energy-saving effect. In this embodiment, a switching power supply is selected as the power supply circuit 20, and this switching power supply is an output voltage adjustable DCDC circuit and has a feedback end, and can adjust the output voltage in real time according to the feedback signal, so as to ensure that the pulse driving circuit 30 obtains a stable input voltage.

[0030] The pulse driving circuit 30 can be a PWM (pulse width modulation) circuit composed of elements such as transistors, resistors and capacitors. Its working principle is to control the brightness of the light emitting element 10 by adjusting the width of the pulse. The PWM circuit has the characteristics of high efficiency and stability, and can accurately control the light emitting intensity of the light emitting element 10 according to the input signal, so as to achieve precise light source driving. Among them, the PWM frequency output by the pulse driving circuit 30 is much greater than the human eye recognition ability.

[0031] The feedback circuit 40 can be a current feedback circuit 40 composed of at least one of components such as operational amplifiers and resistors. Its function is to monitor the current signal output by the pulse drive circuit 30 and convert this signal into a voltage signal for feedback to the power supply circuit 20. When the operating current of the light-emitting component 10 changes, the feedback circuit 40 can respond quickly and maintain the stability of the operating current by adjusting the output voltage of the power supply circuit 20. This feedback mechanism ensures that the light source drive circuit can provide a stable current output under various load conditions, thus guaranteeing the stability and reliability of the light-emitting component 10.

[0032] As Figure 10 shown, in this embodiment, by adopting the pulse drive circuit 30 and connecting the output of the feedback circuit 40 to the feedback terminal of the power supply circuit 20, since the driving ability of the pulse drive circuit 30 is stronger than that of the constant current source and its current output ability is greater, in Figure 10 it can be seen first that the current I1 output by the pulse drive circuit 30 is slightly greater than the output current I2 of the constant current source, which can better ensure the total light output of the light-emitting component 10. And it can be clearly seen in the figure that in the non-conducting position of the pulse drive circuit 30, that is, the shaded part in the figure, since there is no current output, therefore, it does not generate heat. That is to say, the method of using the pulse drive circuit 30 generates at least half less heat than the method of outputting current by the constant current source. Therefore, its heat dissipation requirement is lower.

[0033] In practical applications, after the power supply circuit 20 outputs voltage and current to the pulse drive circuit 30 according to the design requirements, the pulse drive circuit 30 will drive the light-emitting component 10 according to a preset PWM signal, making it emit light at a specific frequency and duty cycle. Due to the high-frequency characteristics of the PWM signal, the change in the brightness of the light-emitting component 10 can hardly be detected by the human eye, so smooth brightness adjustment can be achieved. When the pulse drive circuit 30 drives the light-emitting component 10, the feedback circuit 40 will continuously receive the current signal output from the output terminal of the pulse drive circuit 30 and convert this current signal into a voltage signal for feedback to the power supply circuit 20. After receiving the feedback signal, the power supply circuit 20 will compare it with the current working state and the preset current value. If there is a difference, the power supply circuit 20 will adjust its output voltage so that the current output by the pulse drive circuit 30 can be maintained at a preset stable value. This dynamic adjustment process is real-time to effectively avoid the phenomenon of unstable light emission caused by current fluctuations. Therefore, it can ensure that the light-emitting component 10 can obtain a stable current supply under different working conditions, thus guaranteeing the stability and reliability of its light emission.

[0034] Optionally, when the current signal exceeds a first preset voltage threshold, the feedback circuit 40 outputs a feedback signal for reducing the output current to the feedback terminal of the power supply circuit 20 to reduce the current output by the power supply circuit 20; when the current signal is lower than a second preset voltage threshold, the feedback circuit 40 outputs a feedback signal for increasing the output current to the feedback terminal of the power supply circuit 20 to increase the current output by the power supply circuit 20.

[0035] The feedback circuit 40 can dynamically adjust the output current of the power supply circuit 20 according to the magnitude of the current signal to ensure that the light-emitting component 10 always operates in an optimal state. For example, when the light-emitting component 10 ages or the load changes, resulting in a decrease in the operating current, the feedback circuit 40 will detect this change and output a feedback signal for increasing the output current, thereby prompting the power supply circuit 20 to increase the output current to compensate for the current loss caused by the aging of the light-emitting component 10 or the load change. On the contrary, when the operating current abnormally increases, the feedback circuit 40 will promptly output a feedback signal for reducing the output current to prevent the light-emitting component 10 from being damaged due to overcurrent. This intelligent current adjustment mechanism greatly improves the adaptability and stability of the light source driving circuit.

[0036] In practical applications, assuming that the first preset voltage threshold is 5V and the second preset voltage threshold is 4V, when the voltage value corresponding to the current signal output by the pulse driving circuit 30 is higher than 5V, it indicates that the current of the current light-emitting component 10 is too large and may exceed its normal operating range. At this time, the feedback circuit 40 will output a feedback signal for reducing the output current to the feedback terminal of the power supply circuit 20. After receiving this signal, the power supply circuit 20 will immediately adjust its output voltage to reduce the current output to the pulse driving circuit 30, thereby preventing the light-emitting component 10 from being damaged due to overcurrent. On the contrary, when the voltage value corresponding to the current signal output by the pulse driving circuit 30 is lower than 4V, it indicates that the current of the current light-emitting component 10 is too small and may not meet its normal operating requirements. At this time, the feedback circuit 40 will output a feedback signal for increasing the output current to the feedback terminal of the power supply circuit 20. After receiving this signal, the power supply circuit 20 will correspondingly increase its output voltage to increase the current output to the pulse driving circuit 30, thereby ensuring that the light-emitting component 10 can obtain sufficient current supply and maintain its normal operating state.

[0037] In this embodiment, a power supply circuit 20, a pulse driving circuit 30, and a feedback circuit 40 are provided. Among them, the power input end of the pulse driving circuit 30 is connected to the power output end of the power supply circuit 20, the output end of the pulse driving circuit 30 is electrically connected to the light-emitting element 10, the input end of the feedback circuit 40 is connected to the output end of the pulse driving circuit 30, and the pulse driving circuit 30 outputs a pulse signal to drive the light-emitting element 10 to work. Then, the feedback circuit 40 receives the current signal output by the pulse driving circuit 30 and outputs a corresponding feedback signal to the feedback end of the power supply circuit 20 according to the current signal, so that the power supply circuit 20 adjusts the output current according to the current signal, which can realize the stable on-off control of the light-emitting element 10, avoid the damage caused by current fluctuation to the light-emitting element 10, and thus enable the source driving circuit to maintain a constant output current when the load changes, ensuring the brightness stability of the light-emitting element 10 and the service life of the device.

[0038] Optionally, referring to Figure 2 , another embodiment of the present invention provides a light source driving circuit. Based on the above Figure 1 -shown embodiment, the feedback circuit 40 includes a first voltage dividing circuit 41 and a first resistor R1 circuit 42, where: The first end of the first voltage dividing circuit 41 is connected to the power output end of the power supply circuit 20, and the output end of the first voltage dividing circuit 41 is connected to the feedback end of the power supply circuit 20; the first end of the first resistor R1 circuit 42 is connected to the second end of the first voltage dividing circuit 41, the first end of the first resistor R1 circuit 42 is connected to the output end of the pulse driving circuit 30, and the second end of the first resistor R1 circuit 42 is grounded.

[0039] The first voltage dividing circuit 41 can be composed of resistors connected in series or in parallel, and is used to divide the voltage output by the power supply circuit 20 and send it to the feedback end of the power supply circuit 20. By adjusting its resistance value, the first voltage dividing circuit 41 can accurately control the voltage value fed back to the power supply circuit 20, thereby realizing the fine adjustment of the output current of the power supply circuit 20. This design enables the light source driving circuit to flexibly adjust the output current according to the actual working requirements of the light-emitting element 10, improving the adaptability and stability of the light source driving circuit.

[0040] The first resistor R1 circuit 42 can be composed of multiple resistors connected in series or in parallel. Its function is to limit the current passing through the light-emitting component 10 and protect the light-emitting component 10 from damage caused by excessive current. In addition, the first resistor R1 circuit 42 can also cooperate with the first voltage-dividing circuit 41 to jointly achieve precise control of the output current of the power supply circuit 20. Compared with the prior art, the prior art often does not provide the first resistor R1 circuit 42, and the second end of its first voltage-dividing circuit 41 is often directly grounded. In this embodiment, the second end of the first voltage-dividing circuit 41 that originally needed to be grounded is connected to the first end of the first resistor R1 circuit 42, so as to sample the current output by the pulse drive circuit 30 through the first resistor R1 circuit 42, convert the sampled current signal into a voltage signal, and then feedback it to the feedback end of the power supply circuit 20 after being divided by the first voltage-dividing circuit 41. In this way, the power supply circuit 20 can accurately adjust its output voltage according to the feedback voltage signal, thereby achieving precise control of the output current. This design not only improves the current control ability of the light source drive circuit but also enhances its adaptability and stability.

[0041] In addition, the specific resistance values of the first voltage-dividing circuit 41 and the first resistor R1 circuit 42 can be flexibly set according to the working characteristics and current requirements of the light-emitting component 10. For example, when the light-emitting component 10 requires a higher working current, the resistance value of the first voltage-dividing circuit 41 can be appropriately reduced to increase the voltage value fed back to the power supply circuit 20, thereby prompting the power supply circuit 20 to increase the output current. On the contrary, when the light-emitting component 10 requires a lower working current, the resistance value of the first voltage-dividing circuit 41 can be appropriately increased to reduce the voltage value fed back to the power supply circuit 20, thereby prompting the power supply circuit 20 to reduce the output current.

[0042] In practical applications, the specific implementation methods of the first voltage-dividing circuit 41 and the first resistor R1 circuit 42 can be selected according to the actual situation. For example, the first voltage-dividing circuit 41 can be implemented by connecting resistors in series, while the first resistor R1 circuit 42 can be implemented by connecting resistors in parallel to achieve the best current control effect, thereby ensuring the brightness and lifespan of the light-emitting component 10.

[0043] Optionally, referring to Figure 3 , another embodiment of the present invention provides a light source drive circuit. Based on the above Figure 1 -shown embodiment, the first voltage-dividing circuit 41 includes a first resistor R1 and a second resistor Rf, where: The first end of the first resistor R1 is connected to the power output end of the power supply circuit 20; the first end of the second resistor Rf is connected to the second end of the first resistor R1, the second end of the second resistor Rf is connected to the first end of the first resistor R1 circuit 42, and the common node of the second resistor Rf and the first resistor R1 is connected to the feedback end of the power supply circuit 20.

[0044] The first resistor R1 and the second resistor Rf are connected in series to form a first voltage dividing circuit 41, which together play a role in voltage division. One end of the first resistor R1 is connected to the power output end of the power supply circuit 20 and bears most of the voltage drop of the power supply voltage. The second resistor Rf is connected between the first resistor R1 and the first resistor R1 circuit 42. By adjusting the resistance ratio of the first resistor R1 and the second resistor Rf, the voltage value sent to the feedback end of the power supply circuit 20 after voltage division can be precisely controlled. This voltage division design is not only simple and effective but also can be flexibly adjusted as needed to meet the accuracy requirements of current control for different light-emitting components 10. In an actual circuit, the specific resistance values of the first resistor R1 and the second resistor Rf need to be accurately calculated according to the working voltage and current requirements of the light-emitting component 10 and the characteristics of the power supply circuit 20. Through reasonable resistance selection, it can be ensured that the voltage value output by the voltage dividing circuit can accurately reflect the working state of the pulse driving circuit 30, thereby providing an accurate feedback signal for the power supply circuit 20.

[0045] Optionally, the first resistor R1 circuit 42 includes a third resistor R2 and a fourth resistor R3, where: The first end of the third resistor R2 is respectively connected to the second end of the first voltage dividing circuit 41 and the output end of the pulse driving circuit 30, and the second end of the third resistor R2 is grounded; the first end of the fourth resistor R3 is respectively connected to the second end of the first voltage dividing circuit 41 and the output end of the pulse driving circuit 30, and the second end of the fourth resistor R3 is grounded.

[0046] The third resistor R2 and the fourth resistor R3 are connected in parallel between the first voltage dividing circuit 41 and the pulse driving circuit 30. They together play a role in current sampling and signal conversion. When the pulse driving circuit 30 outputs current, the current will flow through the third resistor R2 and the fourth resistor R3, thereby generating a voltage drop across them. This voltage drop can be regarded as a reflection of the current output by the pulse driving circuit 30, or an "image" of this current. By measuring this voltage drop, we can indirectly know the magnitude of the current output by the pulse driving circuit 30.

[0047] Among them, the output Vout of the power supply circuit 20 is determined according to the light-emitting component 10 used, which is a suitable voltage value for turning on and lighting the light-emitting component 10 and can be calculated by the following formula: Vout = Vop + Vfbi ①; R fbi = R2 / / R3 = ②; V fbi = I * R fbi ③; From ①②③, we get: ; In the formula, Vop is the conduction voltage across the light-emitting component 10, and this parameter is determined according to the specification of the light-emitting component 10; I is the conduction current, and this parameter is determined by referring to the requirements and the specification of the light-emitting component 10.

[0048] When the output Vout of the power supply circuit 20 increases, the conduction current I of the light-emitting component 10 increases, the voltage of the feedback signal Vfbi increases, and the current flowing through the second resistor Rf decreases. Therefore, the output Vout of the power supply circuit 20 decreases. Similarly, when the output Vout of the power supply circuit 20 decreases, the conduction current I of the light-emitting component 10 decreases, the voltage of the feedback signal Vfbi decreases, and the current flowing through the second resistor Rf increases. Therefore, the output Vout of the power supply circuit 20 increases. Through this feedback self-adjustment, the output Vout of the power supply circuit 20 is maintained at a constant voltage, thereby keeping the current of the light-emitting component 10 constant.

[0049] Therefore, it can be calculated by the following formula: ④; From ②③④, we obtain ); Among them, V fb is the internal feedback reference voltage of the DCDC chip and can be obtained from the data sheet of the DCDC chip. When selecting the first resistor R1, the second resistor Rf, the third resistor R2, and the fourth resistor R3, pay attention to selecting resistors with high precision, such as ±1% or better. Among them, the second resistor Rf and the third resistor R2 are low-value resistors (within 10 ohms). The design advantage of the second resistor Rf or the third resistor R2 here is that the current of the light-emitting component 10 is relatively large, and the parallel design can meet the power consumption requirements with ordinary resistors, replacing high-power-consuming resistors and reducing costs.

[0050] Optionally, referring to Figure 4 , another embodiment of the present invention provides a light source driving circuit. Based on the above Figure 1 shown embodiment, the power supply circuit 20 includes a power supply chip U1, a fifth resistor R6, a first capacitor C3, and a first inductor L1, where: The power input terminal of the power chip U1 is used to connect to an external power supply; the second terminal of the fifth resistor R6 is connected to the enable terminal of the power chip U1; the first terminal of the first capacitor C3 is connected to the bootstrap terminal of the power chip U1, and the second terminal of the first capacitor C3 is connected to the switch terminal of the power chip U1; the first terminal of the first inductor L1 is connected to the switch terminal of the power chip U1, and the second terminal of the first inductor L1 is the output terminal of the power circuit 20. At least one capacitor can be connected in parallel or in series between the power output terminal of the power chip U1 and the ground.

[0051] The power chip U1 is a DCDC power chip U1, which converts the input power supply VCC_IN into the required power supply Vout. An adjustable-output DCDC is selected, where the FB pin is the feedback input, which is used to set the output of the power chip U1 through an internal resistor divider to adjust to the required value. The first capacitor C3 or the capacitor connected to the power output terminal of the power chip U1 are all voltage-regulating and filtering capacitors, and the number and capacitance value of the capacitors are selected as needed. For example, a 10uF voltage-regulating capacitor + a 100nF filtering capacitor.

[0052] The fifth resistor R6 is the enable resistor of the power chip U1, and its resistance value determines the startup voltage of the power chip U1. Selecting an appropriate resistance value can ensure that the power chip U1 works normally when the input voltage reaches the preset value. The first capacitor C3 is a bootstrap capacitor, which is connected between the bootstrap terminal and the switch terminal of the power chip U1, and is used to provide necessary charge replenishment when the power chip U1 is working to ensure the stable output of the power chip U1. The first inductor L1 plays the role of energy storage and filtering. It is connected between the switch terminal and the output terminal of the power chip U1, and can smooth the voltage fluctuation of the output of the power chip U1 to ensure the stability and reliability of the output voltage.

[0053] In practical applications, the specific design of the power circuit 20 needs to be comprehensively considered according to the working voltage and current requirements of the light-emitting component 10 and the characteristics of the external power supply. By reasonably selecting the model of the power chip U1, the resistance value of the enable resistor, the capacitance value of the bootstrap capacitor and the filtering capacitor, and the inductance value of the energy storage inductor, it can be ensured that the power circuit 20 can provide a stable and reliable current supply for the light-emitting component 10, while ensuring the working efficiency and stability of the entire light source driving circuit.

[0054] Optionally, referring to Figure 5 , another embodiment of the present invention provides a light source driving circuit. Based on the above Figure 1 shown embodiment, the pulse driving circuit 30 includes a switching transistor Q1 and a sixth resistor R4, where: The first conducting end of the switching transistor Q1 is connected to the negative electrode of the light-emitting component 10, and the second conducting end of the switching transistor Q1 is connected to the input end of the feedback circuit 40; the second end of the sixth resistor R4 is connected to the controlled end of the switching transistor Q1.

[0055] The sixth resistor R4 is a current-limiting resistor, and can reduce the fluctuation amplitude of the LCR oscillation formed by the PCB wiring inductance, wiring resistance and junction capacitance, and reduce the risk of unstable MOS transistor turn-on.

[0056] The switching transistor Q1 can be an N-channel MOS transistor or a P-channel MOS transistor. Its controlled end is the gate, the first conducting end is the drain, and the second conducting end is the source. In practical applications, the selection of the switching transistor Q1 needs to consider factors such as the current demand, operating voltage of the light-emitting component 10, and the operating frequency of the pulse driving circuit 30. By reasonably selecting the model and parameters of the switching transistor Q1, it can be ensured that the pulse driving circuit 30 can accurately output the required pulse signal to drive the light-emitting component 10 to work stably. In addition, the resistance value of the sixth resistor R4 also needs to be accurately calculated according to the characteristics of the switching transistor Q1 and the requirements of the pulse driving circuit 30 to ensure the stability and reliability of the circuit. This design enables the light source driving circuit to flexibly adapt to different light-emitting components 10 and working environments, improving its versatility and practicality.

[0057] Optionally, referring to Figure 6 , another embodiment of the present invention provides a light source driving circuit. Based on the above Figure 1 shown embodiment, the light source driving circuit further includes a drive control circuit 50, wherein: The power input end of the drive control circuit 50 is connected to the output end of the power supply circuit 20, and the output end of the drive control circuit 50 is connected to the controlled end of the pulse driving circuit 30.

[0058] The drive control circuit 50 can be an MCU, or other types of control chips U2 can be used, such as DSP, FPGA, etc. The specific selection depends on the requirements of the actual application. The main function of the drive control circuit 50 is to receive external control signals and generate corresponding control signals according to preset logic or algorithms to drive the pulse driving circuit 30 to work. Through the drive control circuit 50, precise control of the light source driving circuit can be achieved, such as adjusting the brightness, on-off state, etc. of the light-emitting component 10.

[0059] In practical applications, the design of the drive control circuit 50 needs to consider multiple factors, including the source, type, frequency, etc. of the control signal, as well as the operating characteristics of the pulse driving circuit 30 and the requirements of the light-emitting component 10. By reasonably selecting the model and parameters of the drive control circuit 50, it can be ensured that the light source driving circuit can work stably and reliably, while meeting the various requirements of the actual application.

[0060] Optionally, referring to Figure 7 , another embodiment of the present invention provides a light source driving circuit. Based on the above Figure 1 shown embodiment, the drive control circuit 50 includes a control chip U2 and a seventh resistor R5, where: The control signal output terminal of the control chip U2 is connected to the sixth resistor R4; the first end of the seventh resistor R5 is connected to the output terminal of the power supply circuit 20, and the second end of the seventh resistor R5 is connected to the power supply input terminal of the control chip U2.

[0061] The control chip U2 can be an MCU or other types of programmable controllers. It is responsible for receiving external instructions or signals and outputting corresponding control signals according to preset programs or algorithms to drive the light source driving circuit to work. The seventh resistor R5 is the power supply resistor for the control chip U2. It is connected between the output terminal of the power supply circuit 20 and the power supply input terminal of the control chip U2 to provide a stable working voltage for the control chip U2. By reasonably selecting the model and parameters of the control chip U2 and the resistance value of the power supply resistor, the stability and reliability of the drive control circuit 50 can be ensured, thereby achieving precise control of the light source driving circuit.

[0062] Among them, the MCU is responsible for outputting a PWM control signal according to a preset instruction. For example, when the PWM duty cycle is 50% and the frequency is 20KHz, and the switching tube Q1 of the pulse drive circuit 30 is an N-channel MOS tube, during the high level of the PWM, the switching tube Q1 is turned on, and the light-emitting component 10 is turned on to emit light; during the low level of the PWM period, the switching tube Q1 is turned off, no current passes through the light component, it does not light up, and no heat is generated by the light-emitting component 10.

[0063] Optionally, referring to Figure 8 , yet another embodiment of the present invention provides a light source driving circuit. Based on the above Figure 1 shown embodiment, the light source driving circuit further includes a light source protection circuit 60, where: The light source protection circuit 60 is electrically connected to the light-emitting component 10, and the light source protection circuit 60 is used to quickly conduct the spike current when the pulse drive circuit 30 is impacted by a current spike.

[0064] The light source protection circuit 60 can be a protection circuit composed of components such as transient voltage suppression diodes (TVS diodes) and metal oxide varistors (MOVs). When abnormal current spikes occur in the pulse drive circuit 30, they can respond quickly and conduct the spike current to the ground or other safe paths, thereby preventing the light-emitting component 10 from being damaged by excessive current impact. The TVS diode has the characteristics of fast response speed and low clamping voltage, and can limit the overvoltage to a safe level within nanoseconds. The metal oxide varistor can provide a stable resistance value within a large voltage range. When the voltage exceeds its threshold, the resistance value will drop rapidly, thereby conducting the overcurrent to the ground.

[0065] Optionally, referring to Figure 9 , another embodiment of the present invention provides a light source drive circuit. Based on the above Figure 1 illustrated embodiment, the light source protection circuit 60 includes a first diode D1, a bidirectional diode ESD1, and a buffer capacitor C4, where: The negative electrode of the first diode D1 is connected to the positive electrode of the light-emitting component 10, and the positive electrode of the first diode D1 is connected to the negative electrode of the light-emitting component 10; the first end of the bidirectional diode ESD1 is connected to the negative electrode of the light-emitting component 10, and the second end of the bidirectional diode ESD1 is grounded; The first end of the buffer capacitor C4 is connected to the positive electrode of the light-emitting component 10, and the second end of the buffer capacitor C4 is connected to the negative electrode of the light-emitting component 10.

[0066] The bidirectional diode ESD1 is an ESD diode. When the negative electrode of the light-emitting component 10 is connected to the housing of the whole machine, there is a risk of being damaged by ESD. Adding this ESD diode can quickly discharge static electricity to prevent the negative electrode of the light-emitting component 10 from being damaged. The buffer capacitor C4 is a filter capacitor, and the first diode D1 is a freewheeling diode, which is used to conduct the spike generated when the switching transistor Q1 is turned off to the power output terminal Vout of the power supply circuit 20 to protect the light-emitting component 10.

[0067] The above are only the preferred embodiments of the present invention, and do not limit the patent scope of the present invention accordingly. Any equivalent structural or equivalent process transformation made by using the specification and drawings of the present invention, or directly or indirectly applied to other related technical fields, shall be included in the patent protection scope of the present invention by the same token.

Claims

1. A light source driving circuit, applied to a light source assembly, wherein the light source assembly comprises at least one light emitting element, and at least one of the light emitting elements is electrically connected to an output end of the light source driving circuit, characterized in that: The light source driving circuit comprises: Power supply circuit; A pulse driving circuit, wherein the power input terminal of the pulse driving circuit is connected to the power output terminal of the power circuit, the output terminal of the pulse driving circuit is electrically connected to the light-emitting element, and the pulse driving circuit is used to output a pulse signal to drive the light-emitting element to work; A feedback circuit, wherein the input end of the feedback circuit is connected to the output end of the pulse drive circuit, and the feedback circuit is used to receive the current signal output by the pulse drive circuit, and output a corresponding feedback signal to the feedback end of the power supply circuit according to the current signal, so that the power supply circuit adjusts the output current according to the current signal.

2. The light source driving circuit according to claim 1, characterized in that: When the current signal exceeds a first preset voltage threshold, the feedback circuit outputs a feedback signal for reducing the output current to a feedback terminal of the power supply circuit, so as to reduce the current output by the power supply circuit; When the current signal is lower than a second preset voltage threshold, the feedback circuit outputs a feedback signal for increasing the output current to a feedback terminal of the power circuit, so as to increase the current output by the power circuit.

3. The light source driving circuit according to claim 1, characterized in that: The feedback circuit comprises: a first voltage-dividing circuit, wherein a first end of the first voltage-dividing circuit is connected to a power output end of the power circuit, and an output end of the first voltage-dividing circuit is connected to a feedback end of the power circuit; A first resistance circuit, wherein a first end of the first resistance circuit is connected to a second end of the first voltage divider circuit, a first end of the first resistance circuit is connected to an output end of the pulse drive circuit, and a second end of the first resistance circuit is grounded.

4. The light source driving circuit according to claim 3, characterized in that: The first voltage divider circuit comprises: a first resistor, wherein a first end of the first resistor is connected to a power output end of the power circuit; a second resistor, wherein a first end of the second resistor is connected to a second end of the first resistor, a second end of the second resistor is connected to a first end of the first resistor circuit, and a common node of the second resistor and the first resistor is connected to a feedback end of the power supply circuit; The first resistance circuit comprises: a third resistor, wherein a first end of the third resistor is respectively connected to the second end of the first voltage divider circuit and the output end of the pulse driving circuit, and a second end of the third resistor is grounded; A fourth resistor, wherein a first end of the fourth resistor is respectively connected to the second end of the first voltage divider circuit and the output end of the pulse driving circuit, and a second end of the fourth resistor is grounded.

5. The light source driving circuit according to claim 1, characterized in that: The power supply circuit comprises: A power chip, wherein the power input terminal of the power chip is used to connect to an external power source; a fifth resistor, a second end of the fifth resistor being connected to the enable end of the power chip; a first capacitor, wherein a first end of the first capacitor is connected to a bootstrap end of the power chip, and a second end of the first capacitor is connected to a switch end of the power chip; A first inductor, wherein a first end of the first inductor is connected to a switch end of the power chip, and a second end of the first inductor is an output end of the power circuit.

6. The light source driving circuit according to claim 1, characterized in that: The pulse driving circuit comprises: A switch tube, wherein a first conduction end of the switch tube is connected to the cathode of the light-emitting element, and a second conduction end of the switch tube is connected to the input end of the feedback circuit; A sixth resistor, wherein a second end of the sixth resistor is connected to the controlled end of the switch tube.

7. The light source driving circuit according to claim 6, characterized in that: The light source driving circuit further includes: A drive control circuit, wherein the power input end of the drive control circuit is connected to the output end of the power circuit, and the output end of the drive control circuit is connected to the controlled end of the pulse drive circuit.

8. The light source driving circuit according to claim 7, characterized in that: The drive control circuit comprises: A control chip, wherein a control signal output terminal of the control chip is connected to the sixth resistor; A seventh resistor, wherein a first end of the seventh resistor is connected to the output end of the power supply circuit, and a second end of the seventh resistor is connected to the power input end of the control chip.

9. The light source driving circuit according to any one of claims 1 to 8, characterized in that: The light source driving circuit further includes: A light source protection circuit is electrically connected to the light emitting element and is used for quickly conducting the peak current when a current peak impact occurs in the pulse driving circuit.

10. The light source driving circuit according to claim 9, characterized in that: The light source protection circuit comprises: a first diode, wherein a cathode of the first diode is connected to an anode of the light-emitting element, and an anode of the first diode is connected to a cathode of the light-emitting element; a bidirectional diode, wherein a first end of the bidirectional diode is connected to the cathode of the light-emitting element, and a second end of the bidirectional diode is grounded; A buffer capacitor, wherein a first end of the buffer capacitor is connected to the positive electrode of the light-emitting element, and a second end of the buffer capacitor is connected to the negative electrode of the light-emitting element.

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