Control circuit and lights

Abstract

The present invention relates to a control circuit and a vehicle lamp, comprising: a main circuit and a positive-score gear circuit or a negative-score gear circuit; a positive-score gear module comprises a positive-score gear resistor; when the positive-score gear resistor works normally, the positive-score gear circuit provides a first control voltage to the main circuit; when any one of a short-circuit fault and an open-circuit fault occurs in the positive-score gear resistor, the positive-score gear circuit provides a second control voltage to the main circuit; the first control voltage is greater than the second control voltage; a negative-score gear module comprises a negative-score gear resistor; when the negative-score gear resistor works normally, the negative-score gear circuit provides a third control voltage to the main circuit; when any one of a short-circuit fault and an open-circuit fault occurs in the negative-score gear resistor, the negative-score gear circuit provides a fourth control voltage to the main circuit; the third control voltage is less than the fourth control voltage. The above control circuit and vehicle lamp can ensure the safety of nighttime driving and give the driver a fault warning.

Description

Technical Field

[0001] The present invention relates to the technical field of vehicle light control, and in particular to a control circuit and a vehicle light. Background Art

[0002] The car lights include an LED light board and an LDM (constant current control module for LED lighting and signal lights) that controls the LED on the LED light board for display. Usually, the corresponding step resistor Rbin is set on the LED light board according to the power demand of the LED to control the display brightness level of the LED. When the LED is connected to the LDM, the LDM will read the voltage or current value on the step resistor Rbin on the LED light board to determine the magnitude of the current output by the LDM to the LED light board. Since the step resistor Rbin is installed on the LED light board and the detection circuit of the step resistor Rbin is located in the LDM, the two need to be connected through a connector and a wiring harness to work. However, inside the car body, the connector will have poor contact, and the wiring harness will also have the risk of short-circuiting to the ground, causing the step resistor Rbin to be open or short-circuited to the ground.

[0003] The types of LDM's perception and action on the step resistance Rbin include the larger the step resistance Rbin, the larger the output power, the smaller the step resistance Rbin, the smaller the output power, that is, the size of the step resistance Rbin is proportional to the output power, and the larger the step resistance Rbin, the smaller the output power, the smaller the step resistance Rbin, the larger the output power, that is, the size of the step resistance Rbin is inversely proportional to the output power.

[0004] Therefore, for LDM whose size of the step resistor Rbin is proportional to the output power, when the step resistor Rbin is open, the LDM will output overpower, which will cause the LED to overheat and burn. When the step resistor Rbin is short-circuited to the ground, the LDM will have no output, which will turn off the LED. For LDM whose size of the step resistor Rbin is inversely proportional to the output power, when the step resistor Rbin is open, the LDM will have no output, which will turn off the LED. When the step resistor Rbin is short-circuited to the ground, the LDM will output overpower, which will cause the LED to overheat and burn. For nighttime driving, the sudden shutdown of lighting and signal lights will cause great safety problems. Summary of the invention

[0005] Based on this, it is necessary to provide a control circuit and a car light to address the problem in traditional technology that the open circuit and short circuit to ground failure of the step resistor Rbin will cause the LED to fail to display, thus posing a threat to the driver's safety.

[0006] A control circuit comprises a main circuit and a positive ratio gear circuit or a negative ratio gear circuit connected to the main circuit; the main circuit is used to control the display brightness gear of an LED according to a control voltage provided by the positive ratio gear circuit or the negative ratio gear circuit;

[0007] The positive ratio gear circuit includes a positive ratio gear module, and the positive ratio gear module includes a positive ratio gear resistor; when the positive ratio gear resistor works normally, the positive ratio gear circuit provides a first control voltage for the main circuit; when any one of a short circuit fault and an open circuit fault occurs in the positive ratio gear resistor, the positive ratio gear circuit provides a second control voltage for the main circuit; the first control voltage is greater than the second control voltage;

[0008] The reverse score gear circuit includes a reverse score gear module, and the reverse score gear module includes a reverse score gear resistor; when the reverse score gear resistor works normally, the reverse score gear circuit provides a third control voltage for the main circuit; when any one of a short circuit fault and an open circuit fault occurs in the reverse score gear resistor, the reverse score gear circuit provides a fourth control voltage for the main circuit; the third control voltage is less than the fourth control voltage.

[0009] In one embodiment, the positive ratio gear circuit further includes:

[0010] A proportional short-circuit protection module, connected to the proportional ratio gear resistor and the main circuit, and used for providing the second control voltage to the main circuit when a short-circuit fault occurs in the proportional ratio gear resistor;

[0011] A proportional open circuit detection module is connected to the proportional ratio gear resistor, and is used to detect whether the proportional ratio gear resistor has an open circuit fault, and output a proportional working signal when the proportional ratio gear resistor has no open circuit fault, and output a proportional open circuit signal when the proportional ratio gear resistor has an open circuit fault;

[0012] A proportional open circuit protection module, used for providing the second control voltage;

[0013] A proportional selection module, wherein the first electrical connection end of the proportional selection module is connected to the proportional open circuit protection module, the second electrical connection end of the proportional selection module is connected to the main circuit, the third electrical connection end of the proportional selection module is connected to the proportional ratio gear position resistor, and the control end of the proportional selection module is connected to the proportional open circuit detection module; when the control end of the proportional selection module receives the proportional working signal, the second electrical connection end of the proportional selection module is connected to the third electrical connection end of the proportional selection module and the second electrical connection end of the proportional selection module is disconnected from the first electrical connection end of the proportional selection module; when the control end of the proportional selection module receives the proportional open circuit signal, the second electrical connection end of the proportional selection module is connected to the first electrical connection end of the proportional selection module and the second electrical connection end of the proportional selection module is disconnected from the third electrical connection end of the proportional selection module.

[0014] In one embodiment, the proportional ratio gear module also includes a proportional first voltage-dividing resistor, and the proportional first voltage-dividing resistor and the proportional ratio gear resistor are connected in series between the power supply and the ground terminal in sequence, and the third electrical connection terminal of the proportional selection module is connected between the proportional first voltage-dividing resistor and the proportional ratio gear resistor.

[0015] In one embodiment, the proportional short-circuit protection module includes a proportional short-circuit protection resistor, which is connected between the proportional first voltage-dividing resistor and the proportional shifting resistor, and the third electrical connection end of the proportional selection module is connected between the proportional first voltage-dividing resistor and the proportional short-circuit protection resistor.

[0016] In one embodiment, the proportional open circuit detection module includes a proportional operational amplifier and a proportional pull-up resistor, the non-inverting input terminal of the proportional operational amplifier is connected between the proportional scale resistor and the proportional short-circuit protection resistor, the reverse input terminal of the proportional operational amplifier inputs a proportional reference voltage, the output terminal of the proportional operational amplifier is connected to the power supply through the proportional pull-up resistor, and the output terminal of the proportional operational amplifier is also connected to the control terminal of the proportional selection module.

[0017] In one embodiment, the proportional open circuit protection module includes a proportional second voltage-dividing resistor, a proportional third voltage-dividing resistor and a proportional fourth voltage-dividing resistor which are sequentially connected in series between the power supply and the ground terminal, the sum of the resistance values ​​of the proportional second voltage-dividing resistor and the proportional third voltage-dividing resistor is equal to the resistance value of the proportional first voltage-dividing resistor, and the resistance value of the proportional fourth voltage-dividing resistor is equal to the resistance value of the proportional short circuit protection resistor.

[0018] In one embodiment, the inverse ratio gear circuit further includes:

[0019] an inverse ratio open circuit protection module, connected to the inverse ratio gear position resistor and the main circuit, and configured to provide the fourth control voltage to the main circuit when an open circuit failure occurs in the inverse ratio gear position resistor;

[0020] An inverse ratio short circuit detection module is connected to the inverse ratio gear resistor, and is used to detect whether the inverse ratio gear resistor has a short circuit fault, and output an inverse ratio working signal when the inverse ratio gear resistor has not a short circuit fault, and output an inverse ratio short circuit signal when the inverse ratio gear resistor has a short circuit fault;

[0021] An inverse short-circuit protection module, used for providing the fourth control voltage;

[0022] An inverse ratio selection module, wherein the first electrical connection end of the inverse ratio selection module is connected to the inverse ratio short-circuit protection module, the second electrical connection end of the inverse ratio selection module is connected to the main circuit, the third electrical connection end of the inverse ratio selection module is connected to the inverse ratio gear position resistor, and the control end of the inverse ratio selection module is connected to the inverse ratio short-circuit detection module; when the control end of the inverse ratio selection module receives the inverse ratio working signal, the second electrical connection end of the inverse ratio selection module is connected to the third electrical connection end of the inverse ratio selection module and the second electrical connection end of the inverse ratio selection module is disconnected from the first electrical connection end of the inverse ratio selection module; when the control end of the inverse ratio selection module receives the inverse ratio short-circuit signal, the second electrical connection end of the inverse ratio selection module is connected to the first electrical connection end of the inverse ratio selection module and the second electrical connection end of the inverse ratio selection module is disconnected from the third electrical connection end of the inverse ratio selection module.

[0023] In one embodiment, the inverse ratio gear module also includes an inverse ratio first voltage-dividing resistor, and the inverse ratio first voltage-dividing resistor and the inverse ratio gear resistor are connected in series between the power supply and the ground terminal in sequence, and the third electrical connection terminal of the inverse ratio selection module is connected between the inverse ratio first voltage-dividing resistor and the inverse ratio gear resistor.

[0024] In one embodiment, the inverse ratio open circuit protection module includes an inverse ratio open circuit protection resistor, and the inverse ratio open circuit protection resistor is connected in parallel to both ends of the inverse ratio gear resistor.

[0025] In one embodiment, the inverse open circuit detection module includes an inverse operational amplifier and an inverse pull-up resistor, the inverse reference voltage is input to the same-direction input terminal of the inverse operational amplifier, the reverse input terminal of the inverse operational amplifier is connected between the inverse ratio gear resistor and the inverse first voltage divider resistor, the output terminal of the inverse operational amplifier is connected to the power supply through the inverse pull-up resistor, and the output terminal of the inverse operational amplifier is also connected to the control terminal of the inverse selection module.

[0026] In one embodiment, the inverse short circuit protection module includes an inverse second voltage-dividing resistor, an inverse third voltage-dividing resistor and an inverse fourth voltage-dividing resistor which are sequentially connected in series between the power supply and the ground terminal, the resistance value of the inverse second voltage-dividing resistor is equal to the resistance value of the inverse first voltage-dividing resistor, and the sum of the resistance values ​​of the inverse third voltage-dividing resistor and the inverse fourth voltage-dividing resistor is equal to the resistance value of the inverse open circuit protection resistor.

[0027] A vehicle lamp comprises an LED, an LED lamp board and a control circuit as described in any one of the above items, wherein the LED and the step-position resistors are both arranged on the LED lamp board.

[0028] The above-mentioned control circuit and car lights can maintain the LED display and reduce the display brightness when the output power of the LDM is proportional to the size of the step resistance or when the output power of the LDM is inversely proportional to the size of the step resistance when the step resistance has an open circuit fault or a short circuit fault, thereby ensuring nighttime driving safety while also giving the driver a fault warning. BRIEF DESCRIPTION OF THE DRAWINGS

[0029] Figure 1 FIG. 4 is a structural block diagram of a control circuit in an embodiment.

[0030] Figure 2 FIG. 4 is a structural block diagram of a control circuit in another embodiment.

[0031] Figure 3 FIG. 4 is a circuit diagram of a control circuit in an embodiment.

[0032] Figure 4 FIG. 4 is a circuit diagram of a control circuit in another embodiment.

[0033] Description of reference numerals:

[0034] 100, main circuit; 200, positive ratio gear circuit; 210, positive ratio gear module; 220, proportional short circuit protection module; 230, proportional open circuit detection module; 240, proportional open circuit protection module; 250, proportional selection module; 300, main circuit; 400, negative ratio gear circuit; 410, negative ratio gear module; 420, negative ratio open circuit protection module; 430, negative ratio short circuit detection module; 440, negative ratio short circuit protection module; 450, negative ratio selection module. DETAILED DESCRIPTION

[0035] In order to make the purpose, technical solution and advantages of the present application more clearly understood, the present application is further described in detail below in conjunction with the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are only used to explain the present application and are not used to limit the present application.

[0036] In the description of the present application, it should be understood that the terms "center", "lateral", "up", "down", "left", "right", "vertical", "horizontal", "top", "bottom", "inside" and "outside" indicate positions or positional relationships based on the positions or positional relationships shown in the accompanying drawings, and are only for the convenience of describing the present application and simplifying the description, rather than indicating or implying that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation, and therefore cannot be understood as a limitation on the present application. In addition, it should be noted that when an element is referred to as being "formed on another element", it may be directly connected to the other element or there may be a centered element at the same time. When an element is considered to be "connected" to another element, it may be directly connected to the other element or there may be a centered element at the same time. In contrast, when an element is referred to as being "directly on" another element, there is no intermediate element.

[0037] The present application provides a control circuit that can maintain LED display and reduce display brightness when a short circuit fault or an open circuit fault occurs in a step-level resistor, thereby ensuring nighttime driving safety while also providing a fault warning to the driver.

[0038] The control circuit includes a main circuit and a positive ratio gear circuit or a negative ratio gear circuit connected to the main circuit. The main circuit is used to control the display brightness gear of the LED according to the control voltage provided by the positive ratio gear circuit or the negative ratio gear circuit.

[0039] The positive ratio gear circuit includes a positive ratio gear module, and the positive ratio gear module includes a positive ratio gear resistor; when the positive ratio gear resistor works normally, the positive ratio gear circuit provides a first control voltage to the main circuit; when any one of a short circuit fault and an open circuit fault occurs in the positive ratio gear resistor, the positive ratio gear circuit provides a second control voltage to the main circuit; the first control voltage is greater than the second control voltage.

[0040] The inverse score gear circuit includes an inverse score gear module, and the inverse score gear module includes an inverse score gear resistor; when the inverse score gear resistor works normally, the inverse score gear circuit provides a third control voltage for the main circuit; when any one of a short circuit fault and an open circuit fault occurs in the inverse score gear resistor, the inverse score gear circuit provides a fourth control voltage for the main circuit; the third control voltage is less than the fourth control voltage.

[0041] Specifically, the main circuit may be located on the LDM, which is a part of the circuit in the LDM that controls the LED on the LED light board, and the positive ratio gear resistor, the negative ratio gear resistor and the LED are located on the LED light board. Figure 1As shown, when the output power of the LDM is proportional to the size of the gearing resistor, the control circuit includes a main circuit 100 and a positive ratio gear circuit 200 connected to the main circuit 100. The main circuit 100 is used to control the display brightness gear of the LED according to the control voltage provided by the positive ratio gear circuit 200, and the greater the control voltage provided by the positive ratio gear circuit 200, the greater the output power of the main circuit 100, and the brighter the display brightness of the LED. Among them, the positive ratio gear circuit 200 includes a positive ratio gear module 210, and the positive ratio gear module 210 includes a positive ratio gear resistor ( Figure 1 (not shown). When the positive ratio gear resistor is operating normally, the positive ratio gear circuit 200 provides a first control voltage to the main circuit 100, and the main circuit 100 controls the display brightness gear of the LED according to the first control voltage; when any one of a short circuit fault and an open circuit fault occurs in the positive ratio gear resistor, the positive ratio gear circuit 200 provides a second control voltage to the main circuit 100, and the main circuit 100 controls the display brightness gear of the LED according to the second control voltage. Since the second control voltage is less than the first control voltage, when any one of a short circuit fault and an open circuit fault occurs in the positive ratio gear resistor, the main circuit 100 can still keep the LED displaying, and the display brightness is lower than when the positive ratio gear resistor is operating normally, and the output power of the main circuit 100 is consistent when the positive ratio gear resistor is short-circuited and when it is open-circuited, so that the display brightness of the LED is also the same.

[0042] like Figure 2 As shown, when the output power of the LDM is inversely proportional to the size of the step resistor, the control circuit includes a main circuit 300 and an inverse step circuit 400 connected to the main circuit 300. The main circuit 300 is used to control the display brightness level of the LED according to the control voltage provided by the inverse step circuit 400, and when the control voltage provided by the inverse step circuit 400 is larger, the output power of the main circuit 300 is smaller, and the display brightness of the LED is darker. Among them, the inverse step circuit 400 includes an inverse step module 410, and the inverse step module 410 includes an inverse step resistor ( Figure 2(not shown). When the reverse ratio gear resistor is operating normally, the reverse ratio gear circuit 400 provides a third control voltage to the main circuit 300, and the main circuit 300 controls the display brightness gear of the LED according to the third control voltage; when any one of the reverse ratio gear resistor short-circuit fault and open-circuit fault occurs, the reverse ratio gear circuit 400 provides a fourth control voltage to the main circuit 300, and the main circuit 300 controls the display brightness gear of the LED according to the fourth control voltage. Since the fourth control voltage is greater than the third control voltage, when any one of the reverse ratio gear resistor short-circuit fault and open-circuit fault occurs, the main circuit 300 can still keep the LED display, and the display brightness is lower than when the reverse ratio gear resistor is operating normally, and the output power of the main circuit 300 is consistent when the reverse ratio gear resistor short-circuit fault occurs and when the reverse ratio gear resistor open-circuit fault occurs, so that the display brightness of the LED is also the same.

[0043] The above control circuit can maintain the LED display and reduce the display brightness when the step resistor has an open circuit fault or a short circuit fault, both when the output power of the LDM is proportional to the size of the step resistor or when the output power of the LDM is inversely proportional to the size of the step resistor, thereby ensuring nighttime driving safety while also giving the driver a fault warning.

[0044] Figure 3 FIG. 1 is a circuit diagram of a control circuit in an embodiment. Figure 3 As shown, the control circuit includes a main circuit 100 and a proportional ratio gear circuit 200. The proportional ratio gear circuit 200 includes a proportional ratio gear module 210, a proportional short circuit protection module 220, a proportional open circuit detection module 230, a proportional open circuit protection module 240 and a proportional selection module 250. The proportional ratio gear module 210 includes a proportional ratio gear resistor Rbin2.

[0045] The proportional short circuit protection module 220 is connected to the proportional ratio gear resistor Rbin2 and the main circuit 100. The proportional short circuit protection module 220 is used to detect whether the proportional ratio gear resistor Rbin2 has a short circuit fault, and provide a second control voltage to the main circuit 100 when the proportional ratio gear resistor Rbin2 has a short circuit fault. The second control voltage can correspond to the voltage corresponding to the rated minimum output gear of the main circuit 100, so that when the proportional ratio gear resistor Rbin2 has a short circuit fault, the output current of the main circuit 100 is the rated minimum current, thereby controlling the LED display brightness to be at the minimum gear.

[0046] The proportional open circuit detection module 230 is connected to the proportional scale gear resistor Rbin2. The proportional open circuit detection module 230 is used to detect whether an open circuit fault occurs in the proportional scale gear resistor Rbin2, and output a proportional working signal when an open circuit fault does not occur in the proportional scale gear resistor Rbin2, and output a proportional open circuit signal when an open circuit fault occurs in the proportional scale gear resistor Rbin2. For example, the proportional open circuit detection module 230 can determine whether an open circuit fault occurs in the proportional scale gear resistor Rbin2 by detecting the voltage across the two ends of the proportional scale gear resistor Rbin2. When the proportional scale gear resistor Rbin2 does not have an open circuit fault, the proportional open circuit detection module 230 outputs a low-level signal as a proportional working signal, and when an open circuit fault occurs in the proportional scale gear resistor Rbin2, the proportional open circuit detection module 230 outputs a high-level signal as a proportional open circuit signal.

[0047] The proportional open circuit protection module 240 is used to provide a second control voltage, that is, the control voltage provided by the proportional open circuit protection module 240 is the same as the control voltage provided by the proportional short circuit protection module 220 when a short circuit fault occurs in the proportional gear resistor Rbin2, so that the display brightness of the LED is the same when a short circuit fault occurs in the proportional gear resistor Rbin2 and an open circuit fault occurs.

[0048] The proportional selection module 250 includes a first electrical connection terminal X21, a second electrical connection terminal X22, a third electrical connection terminal X23 and a control terminal X24. The first electrical connection terminal X21 of the proportional selection module 250 is connected to the proportional open circuit protection module 240, the second electrical connection terminal X22 of the proportional selection module 250 is connected to the main circuit 100, the third electrical connection terminal X23 of the proportional selection module 250 is connected to the proportional ratio gear resistor Rbin2, and the control terminal X24 of the proportional selection module 250 is connected to the proportional open circuit detection module 230. When the control terminal X24 of the proportional selection module 250 receives the proportional working signal, the second electrical connection terminal X22 of the proportional selection module 250 is connected to the third electrical connection terminal X23 of the proportional selection module 250 and the second electrical connection terminal X22 of the proportional selection module 250 is disconnected from the first electrical connection terminal X21 of the proportional selection module 250. If the proportional ratio gear resistor Rbin2 does not have a short circuit fault at this time, the proportional ratio gear circuit 200 provides the first control voltage to the main circuit 100. If the proportional ratio gear resistor Rbin2 has a short circuit fault at this time, due to the action of the proportional short circuit protection module 220, the proportional ratio gear circuit 200 provides the second control voltage to the main circuit 100. When the control terminal X24 of the proportional selection module 250 receives a proportional open circuit signal, the second electrical connection terminal X22 of the proportional selection module 250 is connected to the first electrical connection terminal X21 of the proportional selection module 250 and the second electrical connection terminal X22 of the proportional selection module 250 is disconnected from the third electrical connection terminal X23 of the proportional selection module 250, and the second control voltage is provided to the main circuit 100 due to the action of the open circuit protection module 240.

[0049] Exemplarily, the proportional ratio module 210 includes a proportional first voltage-dividing resistor R21 and a proportional ratio resistor Rbin2 connected in series between the power supply and the ground terminal. The third electrical connection terminal X23 of the proportional selection module 250 is connected between the proportional first voltage-dividing resistor R21 and the proportional ratio resistor Rbin2.

[0050] Exemplarily, the proportional short circuit protection module 220 includes a proportional short circuit protection resistor R22. The proportional short circuit protection resistor R22 is connected between the proportional first voltage divider resistor R21 and the proportional shift resistor Rbin2, and the third electrical connection terminal X23 of the proportional selection module 250 is connected between the proportional first voltage divider resistor R21 and the proportional short circuit protection resistor R22.

[0051] When the proportional scale resistor Rbin2 does not have a short circuit fault, the series equivalent resistance of the proportional short-circuit protection resistor R22 and the proportional scale resistor Rbin2 is divided by the proportional first voltage-dividing resistor R21, so that the first control voltage is output from point A to the main circuit 100, and the main circuit 100 outputs a normal current according to the first control voltage to control the LED to display the normal brightness level. When a short circuit fault occurs in the proportional scale resistor Rbin2, the proportional short-circuit protection resistor R22 takes on the work of the entire scale resistor, so that the second control voltage is output from point A to the main circuit 100, and the output power of the main circuit 100 is the output power of the level corresponding to the proportional short-circuit protection resistor R22, thereby meeting the requirements that the LED is not too bright and not turned off. When the proportional ratio gear resistor Rbin2 returns to normal, the proportional ratio gear resistor Rbin2 is reconnected to the circuit, the series resistance of the proportional short-circuit protection resistor R22 and the proportional ratio gear resistor Rbin2 returns to normal, and the output of the main circuit 100 returns to normal, so that the display brightness of the LED is readjusted to the normal display brightness level.

[0052] Optionally, the proportional short-circuit protection resistor R22 can be selected as the resistance value corresponding to the rated minimum output gear of the main circuit 100. Then, when the proportional gear resistor Rbin2 is short-circuited to the ground, the output current of the main circuit 100 is the rated minimum current, which can meet the failure safety requirements within the entire application range of the main circuit 100.

[0053] Exemplarily, the proportional selection module 250 may include any one of an analog path selector, an electrically controlled mechanical switch, a relay, a discrete MOS tube, and a discrete triode. When the control terminal X24 of the proportional selection module 250 receives a low level, it can control the second electrical connection terminal X22 and the third electrical connection terminal X23 of the proportional selection module 250 to be connected and the second electrical connection terminal X22 and the first electrical connection terminal X21 of the proportional selection module 250 to be disconnected; when the control terminal X24 of the proportional selection module 250 receives a high level, it can control the second electrical connection terminal X22 and the third electrical connection terminal X23 of the proportional selection module 250 to be disconnected and the second electrical connection terminal X22 and the first electrical connection terminal X21 of the proportional selection module 250 to be connected.

[0054] Exemplarily, the proportional open circuit detection module 230 includes a proportional operational amplifier U21 and a proportional pull-up resistor R23. The proportional operational amplifier U21 and the proportional pull-up resistor R23 can form a comparator. The same-direction input terminal of the proportional operational amplifier U21 is connected between the proportional scale resistor Rbin2 and the proportional short-circuit protection resistor R22, the reverse input terminal of the proportional operational amplifier U21 inputs the proportional reference voltage Vth, the output terminal of the proportional operational amplifier U21 is connected to the power supply through the proportional pull-up resistor R23, and the output terminal of the proportional operational amplifier U21 is connected to the control terminal X24 of the proportional selection module 250.

[0055] Optionally, the proportional reference voltage Vth at point C is slightly less than the power supply voltage, so as to ensure that the comparator can be reliably triggered when an open circuit fault occurs in the proportional ratio gear resistor Rbin2. When the proportional ratio gear resistor Rbin2 does not have an open circuit fault, the voltage Vbin_ext at point B is less than the proportional reference voltage Vth at point C, and the comparator outputs a low level as a proportional working signal. After the control terminal X24 of the proportional selection module 250 receives the proportional working signal, the second electrical connection terminal X22 of the proportional selection module 250 is connected to the third electrical connection terminal X23 and the second electrical connection terminal X22 of the proportional selection module 250 is disconnected from the first electrical connection terminal X21, so that the main circuit 100 is normally connected to the proportional ratio gear module 210, and when the proportional ratio gear resistor Rbin2 does not have a short circuit fault, point A outputs a first control voltage to the main circuit 100, and when a short circuit fault occurs in the proportional ratio gear resistor Rbin2, point A outputs a second control voltage to the main circuit 100. When an open circuit fault occurs in the proportional ratio gear resistor Rbin2, the voltage Vbin_ext at point B is greater than the proportional reference voltage Vth at point C, and the comparator outputs a high level as a proportional open circuit signal. After the control terminal X24 of the proportional selection module 250 receives the proportional open circuit signal, the second electrical connection terminal X22 of the proportional selection module 250 is disconnected from the third electrical connection terminal X23, and the second electrical connection terminal X22 of the proportional selection module 250 is connected to the first electrical connection terminal X21, so that the main circuit 100 is disconnected from the proportional ratio gear module 210, and the main circuit 100 is connected to the proportional open circuit protection module 240, and the proportional open circuit protection module 240 outputs a second control voltage from point D to the main circuit 100, and the LED display brightness is reduced. After the open circuit fault of the proportional gear resistor Rbin2 is removed, the voltage Vbin_ext at point B is less than the proportional reference voltage Vth at point C, the comparator outputs a low level as a proportional working signal, the control voltage of the main circuit 100 is restored to the first control voltage, and the LED returns to normal display brightness level.

[0056] Exemplarily, the proportional open circuit protection module 240 includes a proportional second voltage-dividing resistor R24, a proportional third voltage-dividing resistor R25, and a proportional fourth voltage-dividing resistor R26, which are sequentially connected in series between the power supply and the ground terminal. By adjusting the ratio of the resistance values ​​of the proportional second voltage-dividing resistor R24 ​​and the proportional third voltage-dividing resistor R25, the proportional reference voltage Vth can be made slightly smaller than the power supply voltage VDD, thereby ensuring that the comparator is reliably triggered when an open circuit fault occurs in the proportional shift resistor Rbin2. In this embodiment, the sum of the resistance values ​​of the proportional second voltage-dividing resistor R24 ​​and the proportional third voltage-dividing resistor R25 is equal to the resistance value of the proportional first voltage-dividing resistor R21, and the resistance value of the proportional fourth voltage-dividing resistor R26 is equal to the resistance value of the proportional short-circuit protection resistor R22, so that the voltage Vbin_Failsafe at point D is equal to the voltage at point A when the proportional scale gear resistor Rbin2 has a short-circuit fault, so that the proportional scale gear circuit 200 can provide the same control voltage, i.e., the second control voltage, to the main circuit 100 when the proportional scale gear resistor Rbin2 has a short-circuit fault and an open-circuit fault, so that the display brightness level of the LED is the same when the proportional scale gear resistor Rbin2 has a short-circuit fault and an open-circuit fault.

[0057] Figure 4 FIG. 1 is a circuit diagram of a control circuit in another embodiment. Figure 4 As shown, the control circuit includes a main circuit 300 and an inverse ratio gear circuit 400. The inverse ratio gear circuit 400 includes an inverse ratio gear module 410, an inverse ratio open circuit protection module 420, an inverse ratio short circuit detection module 430, an inverse ratio short circuit protection module 440 and an inverse ratio selection module 450. The inverse ratio gear module 410 includes an inverse ratio gear resistor Rbin4.

[0058] The inverse ratio open circuit protection module 420 is connected to the inverse ratio gear resistor Rbin4 and the main circuit 300. The inverse ratio open circuit protection module 420 is used to detect whether the inverse ratio gear resistor Rbin4 has an open circuit fault, and provide a fourth control voltage to the main circuit 300 when the inverse ratio gear resistor Rbin4 has an open circuit fault. The fourth control voltage may correspond to the voltage corresponding to the rated minimum output gear of the main circuit 300, so that when the inverse ratio gear resistor Rbin4 has an open circuit fault, the output current of the main circuit 300 is the rated minimum current, thereby controlling the LED display brightness to be at the minimum gear.

[0059] The inverse ratio short circuit detection module 430 is connected to the inverse ratio gear resistor Rbin4. The inverse ratio short circuit detection module 430 is used to detect whether a short circuit fault occurs in the inverse ratio gear resistor Rbin4, and output an inverse ratio working signal when the inverse ratio gear resistor Rbin4 does not have a short circuit fault, and output an inverse ratio short circuit signal when a short circuit fault occurs in the inverse ratio gear resistor Rbin4. For example, the inverse ratio short circuit detection module 430 can determine whether a short circuit fault occurs in the inverse ratio gear resistor Rbin4 by detecting the voltage across the inverse ratio gear resistor Rbin4. When the short circuit fault does not occur in the inverse ratio gear resistor Rbin4, the inverse ratio short circuit detection module 430 outputs a low level signal as an inverse ratio working signal, and when a short circuit fault occurs in the inverse ratio gear resistor Rbin4, the inverse ratio short circuit detection module 430 outputs a high level signal as an inverse ratio short circuit signal.

[0060] The inverse ratio short circuit protection module 440 is used to provide a fourth control voltage, that is, the control voltage provided by the inverse ratio short circuit protection module 440 is the same as the control voltage provided by the inverse ratio open circuit protection module 420 when an open circuit fault occurs in the inverse ratio gear resistor Rbin4, so that the display brightness of the LED is the same when an open circuit fault occurs in the inverse ratio gear resistor Rbin4 and a short circuit fault occurs.

[0061] The inverse ratio selection module 450 includes a first electrical connection terminal X41, a second electrical connection terminal X42, a third electrical connection terminal X43 and a control terminal X44. The first electrical connection terminal X41 of the inverse ratio selection module 450 is connected to the inverse ratio short circuit protection module 440, the second electrical connection terminal X42 of the inverse ratio selection module 450 is connected to the main circuit 300, the third electrical connection terminal X43 of the inverse ratio selection module 450 is connected to the inverse ratio gear resistor Rbin4, and the control terminal X44 of the inverse ratio selection module 450 is connected to the inverse ratio short circuit detection module 430. When the control terminal X44 of the inverse ratio selection module 450 receives the inverse ratio working signal, the second electrical connection terminal X42 of the inverse ratio selection module 450 is connected to the third electrical connection terminal X43 of the inverse ratio selection module 450 and the second electrical connection terminal X42 of the inverse ratio selection module 450 is disconnected from the first electrical connection terminal X41 of the inverse ratio selection module 450. If the inverse ratio gear resistor Rbin4 has no open circuit failure at this time, point E outputs the third control voltage to the main circuit 300. If the inverse ratio gear resistor Rbin4 has an open circuit failure at this time, due to the action of the inverse ratio open circuit protection module 420, point E outputs the fourth control voltage to the main circuit 300. When the control terminal X44 of the inverse ratio selection module 450 receives an inverse ratio short-circuit signal, the second electrical connection terminal X42 of the inverse ratio selection module 450 is connected to the first electrical connection terminal X41 of the inverse ratio selection module 450 and the second electrical connection terminal X42 of the inverse ratio selection module 450 is disconnected from the third electrical connection terminal X43 of the inverse ratio selection module 450, and the fourth control voltage is provided to the main circuit 300 due to the action of the short-circuit protection module 440.

[0062] Exemplarily, the inverse ratio range module 410 includes an inverse ratio first voltage divider resistor R41 and an inverse ratio range resistor Rbin4 connected in series between the power supply and the ground terminal. The third electrical connection terminal X43 of the inverse ratio selection module 450 is connected between the inverse ratio first voltage divider resistor R41 and the inverse ratio range resistor Rbin4.

[0063] Exemplarily, the inverse ratio open circuit protection module 420 includes an inverse ratio open circuit protection resistor R42. The inverse ratio open circuit protection resistor R42 is connected in parallel to both ends of the inverse ratio gear resistor Rbin4.

[0064] When the inverse ratio gear resistor Rbin4 does not have an open circuit fault, the parallel equivalent resistance of the inverse ratio open circuit protection resistor R42 and the inverse ratio gear resistor Rbin4 divides the voltage with the inverse ratio first voltage divider resistor R41, so that the third control voltage is output from point E to the main circuit 300, and the main circuit 300 outputs a normal current according to the third control voltage to control the LED to display the normal brightness gear. When the inverse ratio gear resistor Rbin4 has an open circuit fault, the inverse ratio open circuit protection resistor R42 takes on the work of the entire gear resistor, so that the fourth control voltage is output from point E to the main circuit 300, and the output power of the main circuit 300 is the output power of the gear corresponding to the inverse ratio open circuit protection resistor R42, thereby meeting the requirements that the LED is not too bright and not turned off. When the inverse ratio gear resistor Rbin4 returns to normal, the inverse ratio gear resistor Rbin4 is reconnected to the circuit, the parallel resistance of the inverse ratio open circuit protection resistor R42 and the inverse ratio gear resistor Rbin4 returns to normal, and the output of the main circuit 300 returns to normal, so that the display brightness of the LED is readjusted to the normal display brightness level.

[0065] Optionally, the inverse proportional open-circuit protection resistor R42 can be selected as the resistance value corresponding to the rated minimum output gear of the main circuit 300. Then, when the inverse proportional gear resistor Rbin4 is short-circuited to the ground, the output current of the main circuit 300 is the rated minimum current, which can meet the failure safety requirements within the entire application range of the main circuit 300.

[0066] Exemplarily, the inverse ratio selection module 450 may include any one of an analog path selector, an electrically controlled mechanical switch, a relay, a discrete MOS tube, and a discrete triode. When the control terminal X44 of the inverse ratio selection module 450 receives a low level, it can control the second electrical connection terminal X42 and the third electrical connection terminal X43 of the inverse ratio selection module 450 to be connected and the second electrical connection terminal X42 and the first electrical connection terminal X41 of the inverse ratio selection module 450 to be disconnected; when the control terminal X44 of the inverse ratio selection module 450 receives a high level, it can control the second electrical connection terminal X42 and the third electrical connection terminal X43 of the inverse ratio selection module 450 to be disconnected and the second electrical connection terminal X42 and the first electrical connection terminal X41 of the inverse ratio selection module 450 to be connected.

[0067] Exemplarily, the inverse open circuit detection module 430 includes an inverse operational amplifier U41 and an inverse pull-up resistor R43. The inverse operational amplifier U41 and the inverse pull-up resistor R43 can form a comparator. The inverse reference voltage Vth2 is input to the same-direction input terminal of the inverse operational amplifier U41, and the inverse input terminal of the inverse operational amplifier U41 is connected between the inverse ratio gear resistor Rbin4 and the inverse first voltage divider resistor R21. The output terminal of the inverse operational amplifier U41 is connected to the power supply through the inverse pull-up resistor R43, and the output terminal of the inverse operational amplifier U41 is also connected to the control terminal X44 of the inverse selection module 450.

[0068] Optionally, the inverse reference voltage Vth2 at point F is slightly greater than the voltage at the ground terminal, thereby ensuring that the comparator can be reliably triggered when the inverse ratio gear resistor Rbin4 has a short circuit fault. When the inverse ratio gear resistor Rbin4 does not have a short circuit fault, the voltage Vbin_ext2 at point E is greater than the inverse reference voltage Vth2 at point F, and the comparator outputs a low level as an inverse working signal. After the control terminal X44 of the inverse ratio selection module 450 receives the inverse working signal, the second electrical connection terminal X42 of the inverse ratio selection module 450 is connected to the third electrical connection terminal X43 and the second electrical connection terminal X42 of the inverse ratio selection module 450 is disconnected from the first electrical connection terminal X41, so that the main circuit 300 is normally connected to the inverse ratio gear module 410. If the inverse ratio gear resistor Rbin4 does not have an open circuit fault, point E outputs a third control voltage to the main circuit 300. If the inverse ratio gear resistor Rbin4 has an open circuit fault, point E outputs a fourth control voltage to the main circuit 300. When the inverse ratio gear resistor Rbin4 is short-circuited, the voltage Vbin_ext2 at point E is less than the inverse ratio reference voltage Vth2 at point F, and the comparator outputs a high level as an inverse ratio short-circuit signal. After the control terminal X44 of the inverse ratio selection module 450 receives the inverse ratio short-circuit signal, the second electrical connection terminal X42 and the third electrical connection terminal X43 of the inverse ratio selection module 450 are disconnected, and the second electrical connection terminal X42 and the first electrical connection terminal X41 of the inverse ratio selection module 450 are connected, so that the main circuit 300 is disconnected from the inverse ratio gear module 410, and the main circuit 300 is connected to the inverse ratio short-circuit protection module 440, and the inverse ratio short-circuit protection module 440 provides the fourth control voltage to the main circuit 300, and the LED display brightness is reduced. After the short-circuit fault of the inverse proportional gear resistor Rbin4 is removed, the voltage Vbin_ext2 at point E is greater than the inverse proportional reference voltage Vth2 at point F, the comparator outputs a low level as an inverse proportional working signal, the control voltage of the main circuit 300 is restored to the third control voltage, and the LED resumes normal display brightness level.

[0069] Exemplarily, the inverse short circuit protection module 440 includes an inverse second voltage-dividing resistor R44, an inverse third voltage-dividing resistor R45, and an inverse fourth voltage-dividing resistor R46 which are sequentially connected in series between the power supply and the ground terminal. By adjusting the resistance value of the inverse fourth voltage-dividing resistor R46 and the ratio of the sum of the resistance values ​​of the inverse second voltage-dividing resistor R44 and the inverse third voltage-dividing resistor R45, the inverse reference voltage Vth2 can be made slightly larger than the voltage of the ground terminal, thereby ensuring that the comparator is reliably triggered when a short circuit fault occurs in the inverse ratio gear resistor Rbin4. The resistance value of the inverse second voltage-dividing resistor R44 is equal to the resistance value of the inverse first voltage-dividing resistor R41, and the sum of the resistance values ​​of the inverse third voltage-dividing resistor R45 and the inverse fourth voltage-dividing resistor R46 is equal to the resistance value of the inverse open-circuit protection resistor R42, so that the voltage Vbin_Failsafe2 at point G is equal to the voltage at point E when an open-circuit fault occurs in the inverse ratio gear resistor Rbin4, so that the inverse ratio gear circuit 400 can provide the same control voltage, i.e., the fourth control voltage, to the main circuit 300 when an open-circuit fault occurs in the inverse ratio gear resistor Rbin4 and a short-circuit fault occurs, so that the display brightness level of the LED is the same when a short-circuit fault occurs in the inverse ratio gear resistor Rbin4 and an open-circuit fault occurs.

[0070] The control circuit can control the LED not to be too bright and not to be turned off when the step resistor has an open circuit fault or a short circuit fault, and the output power is the same under the two faults, that is, the display brightness level of the controlled LED is the same, and it can be self-recovered after the fault is removed, so that the display brightness level of the LED is restored to a normal level. In addition, the control circuit contains commonly used components, which is conducive to reducing costs and can ensure the safety of functional failure when the step resistor of most LEDs is open circuit or short circuited to the ground.

[0071] The present application also provides a vehicle lamp. The vehicle lamp comprises an LED, an LED lamp board and a control circuit as in any one of the above embodiments. The LED and the step resistors are both arranged on the LED lamp board.

[0072] The technical features of the above-described embodiments may be arbitrarily combined. To make the description concise, not all possible combinations of the technical features in the above-described embodiments are described. However, as long as there is no contradiction in the combination of these technical features, they should be considered to be within the scope of this specification.

[0073] The above-mentioned embodiments only express several implementation methods of the present invention, and the descriptions thereof are relatively specific and detailed, but they cannot be understood as limiting the scope of the invention patent. It should be pointed out that, for ordinary technicians in this field, several variations and improvements can be made without departing from the concept of the present invention, and these all belong to the protection scope of the present invention. Therefore, the protection scope of the patent of the present invention shall be subject to the attached claims.

Claims

1. A control circuit, It is characterized in that It comprises a main circuit and a positive ratio gear position circuit or a negative ratio gear position circuit connected to the main circuit; the main circuit is used to control the display brightness gear position of the LED according to the control voltage provided by the positive ratio gear position circuit or the negative ratio gear position circuit; The positive ratio gear position circuit comprises: A positive ratio gear module, the positive ratio gear module comprising a positive ratio gear resistor; when the positive ratio gear resistor is working normally, the positive ratio gear circuit provides a first control voltage for the main circuit; when any one of a short circuit fault and an open circuit fault occurs in the positive ratio gear resistor, the positive ratio gear circuit provides a second control voltage for the main circuit; the first control voltage is greater than the second control voltage; A proportional open circuit detection module is connected to the proportional ratio gear resistor, and is used to detect whether the proportional ratio gear resistor has an open circuit fault, and output a proportional working signal when the proportional ratio gear resistor has no open circuit fault, and output a proportional open circuit signal when the proportional ratio gear resistor has an open circuit fault; A proportional open circuit protection module, used for providing the second control voltage; A proportional selection module, wherein a first electrical connection end of the proportional selection module is connected to the proportional open circuit protection module, a second electrical connection end of the proportional selection module is connected to the main circuit, a third electrical connection end of the proportional selection module is connected to the proportional ratio gear position resistor, and a control end of the proportional selection module is connected to the proportional open circuit detection module; when the control end of the proportional selection module receives the proportional working signal, the second electrical connection end of the proportional selection module is connected to the third electrical connection end of the proportional selection module and the second electrical connection end of the proportional selection module is disconnected from the first electrical connection end of the proportional selection module; when the control end of the proportional selection module receives the proportional open circuit signal, the second electrical connection end of the proportional selection module is connected to the first electrical connection end of the proportional selection module and the second electrical connection end of the proportional selection module is disconnected from the third electrical connection end of the proportional selection module; wherein the proportional selection module includes any one of an analog path selector, an electrically controlled mechanical switch, a relay, a discrete MOS tube, and a discrete triode; The inverse ratio gear position circuit comprises: An inverse score gear position module, the inverse score gear position module comprising an inverse score gear position resistor; when the inverse score gear position resistor works normally, the inverse score gear position circuit provides a third control voltage for the main circuit; when any one of a short circuit fault and an open circuit fault occurs in the inverse score gear position resistor, the inverse score gear position circuit provides a fourth control voltage for the main circuit; the third control voltage is less than the fourth control voltage; An inverse ratio short circuit detection module is connected to the inverse ratio gear resistor, and is used to detect whether the inverse ratio gear resistor has a short circuit fault, and output an inverse ratio working signal when the inverse ratio gear resistor has not a short circuit fault, and output an inverse ratio short circuit signal when the inverse ratio gear resistor has a short circuit fault; An inverse short-circuit protection module, used for providing the fourth control voltage; An inverse ratio selection module, wherein a first electrical connection end of the inverse ratio selection module is connected to the inverse ratio short-circuit protection module, a second electrical connection end of the inverse ratio selection module is connected to the main circuit, a third electrical connection end of the inverse ratio selection module is connected to the inverse ratio gear position resistor, and a control end of the inverse ratio selection module is connected to the inverse ratio short-circuit detection module; when the control end of the inverse ratio selection module receives the inverse ratio working signal, the second electrical connection end of the inverse ratio selection module is connected to the third electrical connection end of the inverse ratio selection module and the second electrical connection end of the inverse ratio selection module is disconnected from the first electrical connection end of the inverse ratio selection module; when the control end of the inverse ratio selection module receives the inverse ratio short-circuit signal, the second electrical connection end of the inverse ratio selection module is connected to the first electrical connection end of the inverse ratio selection module and the second electrical connection end of the inverse ratio selection module is disconnected from the third electrical connection end of the inverse ratio selection module; wherein the inverse ratio selection module includes any one of an analog path selector, an electrically controlled mechanical switch, a relay, a discrete MOS tube, and a discrete triode.

2. The control circuit according to claim 1, It is characterized in that The positive ratio gear position circuit also includes: A proportional short-circuit protection module is connected to the proportional scale resistor and the main circuit, and is used to provide the second control voltage to the main circuit when a short-circuit fault occurs in the proportional scale resistor.

3. The control circuit according to claim 1, It is characterized in that The proportional ratio gear module also includes a proportional first voltage-dividing resistor, which is connected in series with the proportional ratio gear resistor between a power supply and a ground terminal in sequence, and the third electrical connection terminal of the proportional selection module is connected between the proportional first voltage-dividing resistor and the proportional ratio gear resistor.

4. The control circuit according to claim 2, It is characterized in that The proportional ratio gear module also includes a proportional first voltage-dividing resistor; the proportional short-circuit protection module includes a proportional short-circuit protection resistor, the proportional short-circuit protection resistor is connected between the proportional first voltage-dividing resistor and the proportional ratio gear resistor, and the third electrical connection end of the proportional selection module is connected between the proportional first voltage-dividing resistor and the proportional short-circuit protection resistor.

5. The control circuit according to claim 4, It is characterized in that The proportional open circuit detection module includes a proportional operational amplifier and a proportional pull-up resistor, the non-inverting input terminal of the proportional operational amplifier is connected between the proportional scale resistor and the proportional short-circuit protection resistor, the inverting input terminal of the proportional operational amplifier inputs a proportional reference voltage, the output terminal of the proportional operational amplifier is connected to a power supply through the proportional pull-up resistor, and the output terminal of the proportional operational amplifier is also connected to the control terminal of the proportional selection module.

6. The control circuit according to claim 5, It is characterized in that The proportional open circuit protection module includes a proportional second voltage-dividing resistor, a proportional third voltage-dividing resistor and a proportional fourth voltage-dividing resistor which are connected in series between the power supply and the ground terminal in sequence. The sum of the resistance values ​​of the proportional second voltage-dividing resistor and the proportional third voltage-dividing resistor is equal to the resistance value of the proportional first voltage-dividing resistor, and the resistance value of the proportional fourth voltage-dividing resistor is equal to the resistance value of the proportional short-circuit protection resistor.

7. The control circuit according to claim 1, It is characterized in that The inverse ratio gear position circuit also includes: The inverse ratio open circuit protection module is connected to the inverse ratio gear position resistor and the main circuit, and is used to provide the fourth control voltage to the main circuit when an open circuit failure occurs in the inverse ratio gear position resistor.

8. The control circuit according to claim 7, It is characterized in that The inverse ratio gear module also includes an inverse ratio first voltage-dividing resistor, which is connected in series with the inverse ratio gear resistor between a power supply and a ground terminal in sequence, and the third electrical connection terminal of the inverse ratio selection module is connected between the inverse ratio first voltage-dividing resistor and the inverse ratio gear resistor.

9. The control circuit according to claim 8, It is characterized in that The inverse ratio open circuit protection module includes an inverse ratio open circuit protection resistor, and the inverse ratio open circuit protection resistor is connected in parallel to both ends of the inverse ratio gear resistor.

10. The control circuit according to claim 9, It is characterized in that The inverse short circuit detection module includes an inverse operational amplifier and an inverse pull-up resistor. The inverse reference voltage is input to the same-direction input terminal of the inverse operational amplifier. The reverse input terminal of the inverse operational amplifier is connected between the inverse ratio gear resistor and the inverse first voltage-dividing resistor. The output terminal of the inverse operational amplifier is connected to the power supply through the inverse pull-up resistor, and the output terminal of the inverse operational amplifier is also connected to the control terminal of the inverse selection module.

11. The control circuit according to claim 10, It is characterized in that The inverse short-circuit protection module includes an inverse second voltage-dividing resistor, an inverse third voltage-dividing resistor and an inverse fourth voltage-dividing resistor which are connected in series between the power supply and the ground terminal in sequence. The resistance value of the inverse second voltage-dividing resistor is equal to the resistance value of the inverse first voltage-dividing resistor, and the sum of the resistance values ​​of the inverse third voltage-dividing resistor and the inverse fourth voltage-dividing resistor is equal to the resistance value of the inverse open-circuit protection resistor.

12. A car light, It is characterized in that It comprises an LED, an LED light board and a control circuit as claimed in any one of claims 1 to 11, wherein the LED and the step-by-step resistors are both arranged on the LED light board.

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