Dimming circuit and dimming lamp

Abstract

The embodiment of the invention discloses a linear dimming circuit and a linear dimming lamp. The dimming circuit comprises a linear dimming chip which is provided with a dimming signal input pin and a constant voltage input pin; the lamp load access circuit is electrically connected with the linear dimming chip and is used for forming a lamp load loop between the linear dimming chip and a lamp load; the voltage division detection circuit is used for detecting the output voltage of a target position, the output voltage is related to the working state of a lamp load in the lamp load access circuit, and the target position is electrically connected with the linear dimming chip, so that the output voltage of the target position is output to the linear dimming chip to serve as a protection action trigger signal of the linear dimming chip; and the lamp load shunt circuit is electrically connected with the current pin of the linear dimming chip, and the linear dimming chip converts the constant voltage into constant current and outputs the constant current to the lamp load through the current pin. The embodiment of the invention has the effects of LED short-circuit protection, ultra-low dimming depth, no stroboflash and the like.

Description

Technical Field

[0001] The present application relates to the field of lamps, and in particular to a linear dimming circuit and a linear dimming lamp. Background Art

[0002] Traditional dimming driver circuits are divided into linear dimming drivers and DC-DC switching dimming drivers. The latter uses a converter with a switching power supply, such as a buck or boost topology, to achieve constant current drive. This architecture outputs current with switching ripple and is not truly flicker-free.

[0003] To achieve true flicker-free operation, linear dimming circuits are often used. This eliminates switching ripple, which is crucial for educational lighting. However, linear dimming has some drawbacks that require improvement and optimization. For example, existing linear dimming solutions lack short-circuit protection. Summary of the Invention

[0004] The embodiments of the present application provide a linear dimming circuit and a dimming lamp, which can achieve short-circuit protection and deep dimming of the lamp load while performing linear dimming.

[0005] According to a first aspect of an embodiment of the present application, a linear dimming circuit is provided, the dimming circuit comprising:

[0006] A linear dimming chip, wherein the linear dimming chip has a dimming signal input pin for receiving a dimming signal and a voltage input pin for receiving a constant voltage;

[0007] A lamp load access circuit is electrically connected to the linear dimming chip and is used to form a lamp load loop between the linear dimming chip and the lamp load;

[0008] a voltage divider detection circuit, configured to detect an output voltage at a target position, wherein the output voltage at the target position is related to an operating state of the lamp load in the lamp load access circuit, and wherein the target position is electrically connected to a linear dimming chip so as to output the output voltage at the target position to the linear dimming chip as a protection action trigger signal for the linear dimming chip;

[0009] The lamp load shunt circuit is electrically connected to the current pin of the linear dimming chip. The linear dimming chip converts the constant voltage into a constant current and outputs the constant current to the lamp load through the current pin.

[0010] Optionally, according to an implementation of the first aspect,

[0011] The lamp load access circuit is electrically connected to the voltage input pin of the linear dimming chip and the drain pin of the built-in MOSFET, and is used to access the lamp load and form a lamp load loop;

[0012] The voltage-dividing detection circuit has a voltage detection terminal electrically connected to the signal trigger pin of the linear dimming chip. When the lamp load is operating normally, the voltage detection terminal outputs a first voltage that enables the linear dimming chip to operate normally. When the lamp load is short-circuited, the voltage detection terminal outputs a second voltage that triggers the linear dimming chip to perform a protection action.

[0013] The lamp load shunt circuit is electrically connected to the source pin of the built-in MOSFET of the linear dimming chip and is used to reduce the current of the source pin.

[0014] Optionally, according to an implementation of the first aspect, the lamp load access circuit includes a lamp load anode terminal electrically connected to the voltage input pin of the linear dimming chip and a lamp load cathode terminal electrically connected to the drain pin of the linear dimming chip.

[0015] Optionally, according to an implementation of the first aspect, no resistor connected in parallel with the lamp load exists in the lamp load access circuit.

[0016] Optionally, according to an implementation of the first aspect, the voltage divider detection circuit has a ground terminal, a first terminal electrically connected to the drain pin of the linear dimming chip, and the voltage detection terminal between the first terminal and the ground terminal, the second voltage is greater than the threshold voltage of the signal trigger pin, and the threshold voltage is greater than or equal to the first voltage.

[0017] Optionally, according to an implementation of the first aspect, the voltage divider detection circuit includes a first resistor between the first end and the voltage detection end and a second resistor between the voltage detection end and the ground end, and the resistance values ​​of the first resistor and the second resistor satisfy: when the lamp load is short-circuited, the voltage at the voltage detection end exceeds the threshold voltage; when the lamp load is working normally, the voltage at the voltage detection end does not exceed the threshold voltage.

[0018] Optionally, according to an implementation of the first aspect, the voltage divider detection circuit includes an N-channel field effect transistor, the gate of the N-channel field effect transistor is electrically connected to the drain pin of the controller via a sixth resistor, the source of the N-channel field effect transistor is grounded via a first resistor and a second resistor connected in series, the drain of the N-channel field effect transistor is electrically connected to the voltage input pin of the linear dimming chip, and the voltage detection end is between the first resistor and the second resistor.

[0019] Optionally, according to an implementation of the first aspect, the resistance values ​​of the first resistor and the second resistor satisfy: when the lamp load is short-circuited, the voltage at the voltage detection end exceeds the threshold voltage of the signal trigger pin; when the lamp load works normally, the voltage at the voltage detection end does not exceed the threshold voltage of the signal trigger pin.

[0020] Optionally, according to an implementation of the first aspect, the lamp load shunt circuit includes a third resistor having one end connected to the power supply end and the other end connected to the source pin;

[0021] A fourth resistor is electrically connected between the source pin of the controller and the ground terminal.

[0022] Optionally, according to an implementation of the first aspect, the sizes of the third resistor and the fourth resistor are related to the dimming depth.

[0023] According to a second aspect of the embodiments of the present application, there is provided a linear dimming lamp, comprising the dimming circuit of the first aspect, and a rectifier module for converting an AC input into a DC output;

[0024] a flyback converter, configured to convert a DC output into a constant voltage output, so as to output the constant voltage to the voltage input pin of the dimming circuit;

[0025] An intelligent module, configured to output a dimming signal to a dimming signal input pin of the dimming circuit;

[0026] A lamp load connected to the dimming circuit is connected to the circuit;

[0027] The dimming circuit converts the constant voltage into a constant current according to the dimming signal to control the brightness of the lamp load.

[0028] By adopting this embodiment, the effects of LED short circuit protection, ultra-low dimming depth, and true flicker-free can be achieved while performing linear dimming. BRIEF DESCRIPTION OF THE DRAWINGS

[0029] Figure 1 is a functional schematic diagram of a linear dimming circuit according to an embodiment of the present application;

[0030] Figure 2 is a circuit diagram of a linear dimming circuit according to an embodiment of the present application;

[0031] Figure 3 is a circuit diagram of a linear dimming circuit according to an embodiment of the present application;

[0032] Figure 4 is a circuit diagram of a shunt circuit of a linear dimming circuit according to an embodiment of the present application;

[0033] Figure 5 is a schematic diagram of a linear dimming lamp according to an embodiment of the present application;

[0034] Figure 6 The present invention is a circuit diagram of a linear dimming circuit provided by a related technology. DETAILED DESCRIPTION

[0035] In order to enable those skilled in the art to better understand the present invention, 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 part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments in the present invention, all other embodiments obtained by ordinary technicians in this field without making creative efforts should fall within the scope of protection of this application.

[0036] It should be understood that the “plurality” mentioned herein refers to two or more than two. In the description of the embodiments of the present application, unless otherwise specified, “ / ” means or, for example, A / B can mean A or B; “and / or” in this article is merely a description of the association relationship of associated objects, indicating that there can be three relationships, for example, A and / or B can mean: A exists alone, A and B exist at the same time, and B exists alone. In addition, in order to facilitate a clear description of the technical solutions of the embodiments of the present application, in the embodiments of the present application, words such as “first” and “second” are used to distinguish between identical or similar items with substantially the same functions and effects. Those skilled in the art can understand that words such as “first” and “second” do not limit the quantity and execution order, and words such as “first” and “second” do not limit certain different

[0037] In addition, the terms "comprises" and "having" and any variations thereof are intended to cover a non-exclusive inclusion. For example, a process, method, system, product or apparatus that includes a series of steps or elements is not necessarily limited to those steps or elements expressly listed but may include other steps or elements not expressly listed or inherent to such process, method, product or apparatus.

[0038] To achieve true flicker-free dimming, linear dimming circuits are often used in dimming drive circuits. This eliminates switching ripple, making it crucial for educational lighting. However, linear dimming has several drawbacks that require improvement and optimization. For example, existing linear dimming solutions lack short-circuit protection, and some solutions also have limited dimming depth.

[0039] Based on this, the embodiment of the present application provides a linear dimming circuit. Figure 1 As shown, the dimming circuit includes the following parts.

[0040] The linear dimming chip 10 has a dimming signal input pin capable of receiving a dimming signal and a voltage input pin for receiving a constant voltage. Exemplarily, the dimming signal is a PWM (Pulse-width modulation) dimming signal.

[0041] The lamp load access circuit 12 is electrically connected to the linear dimming chip to form a lamp load loop between the linear dimming chip and the lamp load. The input voltage of the lamp load access circuit 12 provides power for the normal operation of the lamp load.

[0042] The voltage divider detection circuit 14 is used to detect the output voltage at the target location. This output voltage is related to the operating status of the lamp load in the lamp load connection circuit. The target location is electrically connected to the linear dimming chip 10 to output the output voltage at the target location to the linear dimming chip 10 as a protection trigger signal for the linear dimming chip 10. When the lamp load is operating normally, the output voltage at the target location will not trigger the linear dimming chip 10's protection. However, when the lamp load is short-circuited, the output voltage at the target location will trigger the linear dimming chip 10's protection.

[0043] The lamp load shunt circuit 16 is electrically connected to the current pin of the linear dimming chip. The linear dimming chip 10 converts the constant voltage into a constant current and outputs the constant current to the lamp load through the current pin.

[0044] The dimming circuit provided in this embodiment uses a voltage divider detection circuit 14 to detect the voltage at the target position while linear dimming is performed and feeds back to the linear dimming chip 10 for lamp load short circuit protection. In addition, the lamp load shunt circuit achieves a deep dimming function.

[0045] Figure 2 : is a circuit diagram of a linear dimming circuit according to an embodiment of the present application. Figure 2 , the dimming circuit includes the following parts.

[0046] The linear dimming chip U1 has a dimming signal input pin (DIM pin as shown in the figure).

[0047] The lamp load access circuit 12 is electrically connected to the voltage input pin VIN of the linear dimming chip U1 and the drain pin (Drain) of the built-in MOSFET, and is used to access the lamp load and form a lamp load loop.

[0048] The voltage divider detection circuit 14 has a voltage detection end electrically connected to the signal trigger pin of the linear dimming chip U1 (for example, the SLP pin (this pin controls the sleep mode of the drive) or the OVB (overvoltage protection function) pin). When the lamp load is operating normally, the voltage detection end outputs a first voltage that enables the linear dimming chip U1 to operate normally. When the lamp load is short-circuited, the voltage detection end outputs a second voltage that triggers the linear dimming chip U1 to perform a protection action.

[0049] The lamp load shunt circuit 16 is electrically connected to the source pin of the built-in MOSFET of the linear dimming chip, and is used to reduce the current of the source pin.

[0050] The dimming circuit provided in this embodiment can, on the one hand, achieve true flicker-free operation. On the other hand, a voltage divider detection circuit 14 is used to detect the voltage of the lamp load (e.g., a light strip) (e.g., the voltage of the cathode of the light strip) and feed it back to the linear dimming chip U1 (e.g., a linear dimming chip) for short-circuit protection. Still further, a deep dimming function is achieved through the lamp load shunt circuit.

[0051] Optionally, in an implementation of this embodiment, the lamp load is an LED (such as LED1 as shown in the figure).

[0052] Optionally, in one implementation of this embodiment, the lamp load access circuit 12 includes a lamp load anode terminal electrically connected to the voltage input pin VIN of the linear dimming chip U1 and a lamp load cathode terminal electrically connected to the drain pin Drain of the linear dimming chip U1. In this embodiment, the lamp load, such as LED1, is directly connected to the circuit without a resistor connected in parallel with the lamp load. This parallel resistor is also called a dummy load resistor, such as Figure 6 In the related art shown, the dummy load resistor R6 plays a certain shunting role, thereby affecting the dimming depth. In this implementation, the dimming depth is affected by the lamp load shunting circuit, and the dummy load resistor can be omitted.

[0053] In addition, if Figure 6In the related technology shown, when the light bar is short-circuited, the MOSFET inside U1 will be quickly broken down, causing damage to the entire circuit. Among them, pins 6-7 of U1 are the Drain and Source pins of the MOSFET. For example: during normal operation, the VELD+ level is 38V, and the voltage drop on the lamp bead LED1 is 36V, then the VLED- level is 38-36=2V; when both ends of LED1 are short-circuited, since VLED+ is the constant voltage power supply for the entire circuit system, its level will not change due to the short circuit of the subsequent stage, so the VLED- level is 38V at this time, which will cause a large current to flow through pins 6-7 instantly, and the internal MOSFET will be damaged due to short-term overheating. The solution provided by the embodiment of the present application can effectively solve this technical problem.

[0054] Optionally, in an implementation of this embodiment, as Figure 2 As shown, the voltage divider detection circuit 14 has a ground terminal, a first terminal electrically connected to the drain pin Drain of the linear dimming chip U1, and a voltage detection terminal between the first terminal and the ground terminal, and the second voltage is greater than the threshold voltage of the signal trigger pin, and the threshold voltage is greater than or equal to the first voltage.

[0055] More specifically, the voltage divider detection circuit 14 includes a first resistor R1 between the first end and the voltage detection end and a second resistor R2 between the voltage detection end and the ground end. The resistance values ​​of the first resistor R1 and the second resistor R2 satisfy: when the lamp load is short-circuited, the voltage at the voltage detection end exceeds the threshold voltage, thereby triggering the linear dimming chip U1 to perform a protection action; when the lamp load is working normally, the voltage at the voltage detection end does not exceed the threshold voltage, and the linear dimming chip U1 works normally.

[0056] For example, when the lamp load is operating normally, VLED+ is 38V, VLED- is 2V, R1 = 5.1mΩ, and R2 = 1mΩ.

[0057] By adopting this implementation, the linear dimming chip U1 can be triggered to perform a protection action in time in response to a short circuit of the lamp load, thereby preventing the linear dimming chip U1 from being damaged.

[0058] Optionally, in an implementation of this embodiment, as Figure 3As shown, the voltage divider detection circuit 14 includes an N-channel field effect transistor Q1, the gate of the N-channel field effect transistor Q1 is electrically connected to the drain pin Drain of the controller U1 via the sixth resistor R6, the source of the N-channel field effect transistor Q1 is grounded via the first resistor R1 and the second resistor R2 connected in series, the drain of the N-channel field effect transistor Q1 is electrically connected to the voltage input pin VIN of the linear dimming chip U1, and the voltage detection end is between the first resistor R1 and the second resistor R2.

[0059] More specifically, the resistance values ​​of the first resistor R1 and the second resistor R2 satisfy the following conditions: when the lamp load is short-circuited, the voltage at the voltage detection end exceeds the threshold voltage of the signal trigger pin, thereby triggering the linear dimming chip U1 to perform a protection action; when the lamp load is working normally, the voltage at the voltage detection end does not exceed the threshold voltage of the signal trigger pin, and the linear dimming chip U1 works normally.

[0060] For example, when the lamp load is operating normally, VLED+ is 38V, VLED- is 2V, R1 = 8.2mΩ, R2 = 8.2mΩ, and R6 = 100Ω.

[0061] This implementation can promptly trigger the linear dimming chip U1 to perform a protective action in response to a short circuit in the lamp load, thereby preventing damage to the linear dimming chip U1. Those skilled in the art will appreciate that the N-channel FET Q1 can be replaced with other types of FETs, which are equivalent to the implementation of this application and are not further described here.

[0062] Optionally, in an implementation of this embodiment, as Figure 2 or Figure 3 As shown, the lamp load shunt circuit 16 includes a third resistor R3 with one end connected to the power supply terminal VCC and the other end connected to the source pin CS. A fourth resistor R4 is electrically connected between the source pin CS of the controller U1 and the ground terminal. The sizes of the third resistor R3 and the fourth resistor R4 are related to the dimming depth.

[0063] Exemplarily, R3 = 10 kΩ, R4 = 1Ω.

[0064] With this implementation, the dimming depth can be affected by selecting R3 and R4 with appropriate resistance values, or by selecting R3 with an appropriate resistance value when the resistance value of R4 is determined.

[0065] The following combination Figure 2 , the advantages of the dimming circuit according to the embodiment of the present application are described in detail with examples. Figure 2In the prior art, when there is no lamp load connected to the circuit 12, when the LED 1 is short-circuited, the MOSFET inside the linear dimming chip U1 will be quickly broken down, causing damage to the entire circuit.

[0066] Pins 6-7 of the linear dimming chip U1 serve as the Drain and Source pins of the MOSFET. For example, during normal operation, the VLED+ voltage level is 38V, and the voltage drop across LED1 is 36V. Therefore, the VLED- voltage level is 38-36 = 2V. If LED1 is short-circuited, VLED+ provides a constant voltage for the entire circuit system, and its voltage level remains unchanged by the subsequent short circuit. Therefore, the VLED- voltage level remains at 38V. This causes a large current to flow through pins 6-7, causing the internal MOSFET to overheat and be damaged.

[0067] like Figure 2 As shown, the embodiment of the present application adds a voltage divider detection circuit of R1 and R2, and sends the detection signal to pin 3 of the linear dimming chip U1 (assuming the threshold level of pin 3 is 2.5V). Among them, 36V / 260mA represents the operating voltage and operating current of the LED during normal operation. When the lamp is working normally, the voltage level detected by the voltage divider of R1 and R2 is given to pin 3 (about 0.33V), and there will be no protection action. When LED1 is short-circuited, the level detected at pin 3 becomes 6.3V, which is greater than the threshold level of 2.5V. The linear dimming chip U1 actively stops working to play a protective role, and the device will not be damaged. In addition, as Figure 2 As shown, the dummy load circuit connected in parallel with LED 1 in the prior art is omitted.

[0068] like Figure 2 As shown, in order to ensure the dimming depth, a pull-up resistor R3 is connected to the CS current detection pin, pin 7 of the linear dimming chip U1. Assume that the current flowing through R3 is Ir3, the current flowing through LED1 (that is, through pins 6-7 of the built-in MOSFET) is Ics, and the current flowing through R4 is Ir4. Figure 4 So, the relationship between them satisfies Ics = Ir4 - Ir3. If VCC = 1.98V (VCC can be an external power supply or the constant voltage source built into the linear dimming chip U1), and the internal reference voltage of 0.26V on the CS pin is constant, then Ir4 = 0.26V ÷ 1Ω = 0.26mA is also constant, and Ir3 = (1.98V - 0.18V) ÷ 10KΩ = 0.18mA. Therefore, the final Ics = 0.26mA - 0.18 = 0.08mA, achieving the same dimming depth as the traditional solution: 0.08 ÷ 260 ≈ 0.03%. Therefore, using the embodiment of the present application, a dimming depth of 10,000 levels can be achieved.

[0069] The embodiment of the present application also provides a linear dimming lamp having Figure 1-3 The linear dimming circuit described in any one of the preceding claims.

[0070] Figure 5 Schematic diagram of a linear dimming lamp according to an embodiment of the present application. Figure 5 , dimming lamps include Figure 1-3 The linear dimming circuit (ie, linear constant current dimming module) described in any one of the above further includes the following parts.

[0071] A rectifier module (eg, an ACDC rectifier module) is used to convert alternating current (AC) into direct current (DC) output.

[0072] The flyback converter is used to convert the DC output into a constant voltage output so as to output the constant voltage to the voltage input pin of the dimming circuit.

[0073] The intelligent module is electrically connected to the dimming signal input pin of the dimming circuit to output a dimming signal to the dimming signal input pin.

[0074] A lamp load connected to the dimming circuit is connected to the circuit to provide light.

[0075] The dimming circuit converts the constant voltage into a constant current according to the dimming signal to control the brightness of the lamp load.

[0076] In this embodiment, the dimming circuit may also be referred to as a linear constant current dimming module due to its linear constant current dimming characteristic.

[0077] By using the dimming lamp provided in this embodiment, effects such as LED short-circuit protection, ultra-low dimming depth, and true flicker-free can be achieved.

[0078] In the several embodiments provided in this application, it should be understood that the disclosed technical content can be implemented in other ways. Among them, the device embodiments described above are only exemplary. For example, the division of the units can be a logical function division. In actual implementation, there may be other division methods, such as multiple units or components can be combined or integrated into another system, or some features can be ignored or not executed. Another point is that the mutual coupling or direct coupling or communication connection shown or discussed can be through some interfaces, indirect coupling or communication connection of units or modules, which can be electrical or other forms.

[0079] The units described as separate components may or may not be physically separate, and the components shown as units may or may not be physical units, that is, they may be located in one place or distributed across multiple units. Some or all of the units may be selected according to actual needs to achieve the purpose of the present embodiment.

[0080] In addition, the functional units in the various embodiments of the present application may be integrated into a single processing unit, or each unit may exist physically separately, or two or more units may be integrated into a single unit. The aforementioned integrated units may be implemented in the form of hardware or software functional units.

[0081] In the above embodiments, it can be implemented in whole or in part by software, hardware, firmware or any combination thereof. When implemented using software, it can be implemented in whole or in part in the form of a computer program product. The computer program product includes one or more computer instructions. When the computer instructions are loaded and executed on a computer, the process or function described in the embodiment of the present application is generated in whole or in part. The computer can be a general-purpose computer, a special-purpose computer, a computer network or other programmable device. The computer instructions can be stored in a computer-readable storage medium or transmitted from one computer-readable storage medium to another computer-readable storage medium. For example, the computer instructions can be transmitted from one website, computer, server or data center to another website, computer, server or data center via a wired (e.g., coaxial cable, optical fiber, digital subscriber line (DSL)) or wireless (e.g., infrared, wireless, microwave, etc.) method. The computer-readable storage medium can be any available medium that can be accessed by a computer, or a data storage device such as a server or data center that includes one or more available media integrated. The available medium may be a magnetic medium (e.g., a floppy disk, a hard disk, or a magnetic tape), an optical medium (e.g., a digital versatile disc (DVD)), or a semiconductor medium (e.g., a solid state disk (SSD)). It is worth noting that the computer-readable storage medium mentioned in the embodiments of the present application may be a non-volatile storage medium, in other words, a non-transient storage medium.

[0082] It should be noted that the information (including but not limited to user device information, user personal information, etc.), data (including but not limited to data used for analysis, stored data, displayed data, etc.) and signals involved in the embodiments of this application are all authorized by the user or fully authorized by all parties, and the collection, use and processing of relevant data must comply with the relevant laws, regulations and standards of the relevant countries and regions. For example, the scene data of the current frame in the three-dimensional virtual scene, the client's device information, and the scene interaction information involved in the embodiments of this application are all obtained with full authorization.

[0083] The above is only a preferred embodiment of the present application. It should be pointed out that for ordinary technicians in this technical field, several improvements and modifications can be made without departing from the principles of the present application. These improvements and modifications should also be regarded as the scope of protection of the present application.

Claims

1. A linear dimming circuit, characterized in that: The dimming circuit includes: A linear dimming chip, wherein the linear dimming chip has a dimming signal input pin for receiving a dimming signal and a voltage input pin for receiving a constant voltage; A lamp load access circuit is electrically connected to the linear dimming chip and is used to form a lamp load loop between the linear dimming chip and the lamp load; a voltage divider detection circuit, configured to detect an output voltage at a target position, wherein the output voltage at the target position is related to an operating state of the lamp load in the lamp load access circuit, and wherein the target position is electrically connected to a linear dimming chip so as to output the output voltage at the target position to the linear dimming chip as a protection action trigger signal for the linear dimming chip; The lamp load shunt circuit is electrically connected to the current pin of the linear dimming chip. The linear dimming chip converts the constant voltage into a constant current and outputs the constant current to the lamp load through the current pin.

2. The linear dimming circuit according to claim 1, wherein: The lamp load access circuit is electrically connected to the voltage input pin of the linear dimming chip and the drain pin of the built-in MOSFET, and is used to access the lamp load and form a lamp load loop; The voltage-dividing detection circuit has a voltage detection terminal electrically connected to the signal trigger pin of the linear dimming chip. When the lamp load is operating normally, the voltage detection terminal outputs a first voltage that enables the linear dimming chip to operate normally. When the lamp load is short-circuited, the voltage detection terminal outputs a second voltage that triggers the linear dimming chip to perform a protection action. The lamp load shunt circuit is electrically connected to the source pin of the built-in MOSFET of the linear dimming chip, and is used to lower the current of the source pin.

3. The linear dimming circuit according to claim 2, wherein: The lamp load access circuit includes a lamp load anode terminal electrically connected to the voltage input pin of the linear dimming chip and a lamp load cathode terminal electrically connected to the drain pin of the linear dimming chip.

4. The linear dimming circuit according to claim 3, wherein: There is no resistor connected in parallel with the lamp load in the lamp load access circuit.

5. The linear dimming circuit according to claim 2, wherein: The voltage divider detection circuit has a ground terminal, a first terminal electrically connected to the drain pin of the linear dimming chip, and a voltage detection terminal between the first terminal and the ground terminal, the second voltage is greater than the threshold voltage of the signal trigger pin, and the threshold voltage is greater than or equal to the first voltage.

6. The linear dimming circuit according to claim 5, characterized in that: The voltage divider detection circuit includes a first resistor between the first end and the voltage detection end and a second resistor between the voltage detection end and the ground end. The resistance values ​​of the first resistor and the second resistor satisfy: when the lamp load is short-circuited, the voltage at the voltage detection end exceeds the threshold voltage; when the lamp load is working normally, the voltage at the voltage detection end does not exceed the threshold voltage.

7. The linear dimming circuit according to claim 1, wherein: The voltage divider detection circuit includes an N-channel field effect transistor, the gate of the N-channel field effect transistor is electrically connected to the drain pin of the controller via a sixth resistor, the source of the N-channel field effect transistor is grounded via a first resistor and a second resistor connected in series, the drain of the N-channel field effect transistor is electrically connected to the voltage input pin of the linear dimming chip, and the voltage detection end is between the first resistor and the second resistor.

8. The linear dimming circuit according to claim 7, wherein: The resistance values ​​of the first resistor and the second resistor satisfy the following requirements: when the lamp load is short-circuited, the voltage of the voltage detection end exceeds the threshold voltage of the signal trigger pin; when the lamp load is working normally, the voltage of the voltage detection end does not exceed the threshold voltage of the signal trigger pin.

9. The linear dimming circuit according to claim 1, wherein: The lamp load shunt circuit includes a third resistor having one end connected to the power supply end and the other end connected to the source pin; A fourth resistor is electrically connected between the source pin of the controller and the ground terminal.

10. The linear dimming circuit according to claim 9, wherein: The sizes of the third resistor and the fourth resistor are related to the dimming depth.

11. A linear dimming lamp, characterized in that: The linear dimming lamp comprises: The linear dimming circuit according to any one of claims 1 to 10; Rectifier module, used to convert AC input into DC output; a flyback converter, configured to convert a DC output into a constant voltage output, so as to output the constant voltage to the voltage input pin of the dimming circuit; An intelligent module, configured to output a dimming signal to a dimming signal input pin of the dimming circuit; A lamp load connected to the dimming circuit is connected to the circuit; The dimming circuit converts the constant voltage into a constant current according to the dimming signal to control the brightness of the lamp load.

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