Constant power control circuit and LED lamp

Abstract

The utility model discloses a constant power control circuit and an LED lamp, which are applied to the technical field of LED illumination. Wherein the first end of the threshold setting circuit is connected with the first end of the driving circuit, the first end of the transistor gate pole protection circuit is connected with the second end of the threshold setting circuit, and the second end of the transistor gate pole protection circuit is connected with the third end of the threshold setting circuit. The third end of the transistor gate pole protection circuit is connected with the first end of the constant power compensation circuit, the second end of the constant power compensation circuit is connected with the first end of the threshold setting circuit and the first end of the driving circuit, and the third end of the constant power compensation circuit is connected with the second end of the driving circuit. According to the invention, a threshold setting circuit sets a starting voltage; the transistor gate protection circuit reduces the starting voltage and prevents the starting voltage from damaging the constant power compensation circuit; and the constant power compensation circuit compares the starting voltage with a voltage threshold value of the constant power compensation circuit so as to carry out power compensation and realize constant power output.

Description

Technical Field

[0001] The utility model relates to the technical field of LED lighting, in particular to a constant power control circuit and an LED lamp. Background Art

[0002] With the advancement of light-emitting diode (LED) lighting technology, an increasing number of LED lamps are adopting a driver-on-board (DOB) circuit solution to make them more compact and improve heat dissipation efficiency. This DOB circuit solution integrates the driver circuitry onto the LED lamp's circuit board, eliminating the need for external driver connections. This saves space and creates a more compact structure. Furthermore, due to its advantages such as simple production process, low cost, high temperature resistance, and small footprint, an increasing number of manufacturers are adopting this approach in their LED lighting product designs.

[0003] However, the DOB solution has the disadvantages of poor linear regulation and narrow operating voltage. When the input voltage increases, the power of the LED lamp will increase with the input voltage, thereby affecting the service life of the product and causing serious problems such as fire due to excessive product temperature.

[0004] In view of the above technology, finding a constant power control circuit is an urgent problem to be solved by those skilled in the art. Utility Model Content

[0005] The purpose of the utility model is to provide a constant power control circuit and an LED lamp, which can solve the serious problems in the prior art such as the power characteristics of the LED lamp itself affecting the product life and fire caused by excessively high product temperature.

[0006] In order to solve the above technical problems, the utility model provides a constant power control circuit, comprising: a constant power compensation circuit, a transistor gate protection circuit, and a threshold setting circuit;

[0007] Wherein, a first terminal of the threshold setting circuit is connected to a first terminal of the driving circuit, and is used to obtain a driving voltage in the driving circuit and set a starting voltage according to the driving voltage;

[0008] A first terminal of the transistor gate protection circuit is connected to a second terminal of the threshold setting circuit, a second terminal of the transistor gate protection circuit is connected to a third terminal of the threshold setting circuit, and a third terminal of the transistor gate protection circuit is connected to a first terminal of the constant power compensation circuit for reducing a startup voltage;

[0009] The second end of the constant power compensation circuit is connected to the first end of the threshold setting circuit and the first end of the driving circuit, and the third end of the constant power compensation circuit is connected to the second end of the driving circuit; it is used to determine whether power compensation is achieved based on the relationship between the starting voltage and its own voltage threshold.

[0010] Preferably, the threshold setting circuit includes: a first voltage regulator tube, a second voltage regulator tube, a first resistor, a second resistor and a first capacitor;

[0011] The first end of the first voltage regulator tube is connected to the first end of the driving circuit and the second end of the constant power compensation circuit as the first end of the threshold setting circuit, and the second end of the first voltage regulator tube is connected to the first end of the second voltage regulator tube;

[0012] The second end of the second voltage-stabilizing tube is connected to the first end of the first resistor;

[0013] The second end of the first resistor is connected to the first end of the second resistor and the first end of the first capacitor, and together serve as the second end of the threshold setting circuit and is connected to the first end of the transistor gate protection circuit;

[0014] The second end of the second resistor is connected to the first end of the first capacitor, and together serve as the third end of the threshold setting circuit and are connected to the second end of the transistor gate protection circuit.

[0015] Preferably, the transistor gate protection circuit includes: a third voltage regulator, a third resistor and a fourth resistor;

[0016] The first end of the third resistor is connected to the second end of the threshold setting circuit as the first end of the transistor gate protection circuit; the second end of the third resistor is connected to the first end of the third voltage regulator diode and the first end of the fourth resistor, and together they serve as the fourth end of the transistor gate protection circuit and are connected to the first end of the constant power compensation circuit;

[0017] The second end of the third voltage regulator tube and the second end of the fourth resistor are connected and serve together as the second end of the transistor gate protection circuit, which is connected to the third end of the threshold setting circuit and is grounded.

[0018] Preferably, the constant power compensation circuit includes: a fifth resistor, a sixth resistor and a first MOS transistor;

[0019] The first end of the fifth resistor is connected to the first end of the threshold setting circuit and the first end of the driving circuit as the second end of the constant power compensation circuit, and the second end of the fifth resistor is connected to the first end of the sixth resistor;

[0020] The second end of the sixth resistor is connected to the drain of the first MOS transistor;

[0021] The gate of the first MOS tube is connected to the third end of the transistor gate protection circuit as the first end of the constant power compensation circuit, and the source of the first MOS tube is connected to the second end of the drive circuit as the third end of the constant power compensation circuit.

[0022] Preferably, it further comprises: a second capacitor;

[0023] The first end of the second capacitor is connected to the second end of the fifth resistor and the first end of the sixth resistor, and the second end of the second capacitor is grounded.

[0024] Preferably, the driving circuit includes: a DOB driving circuit, a lighting circuit and an adjustment circuit;

[0025] Wherein, a first end of the DOB driving circuit is connected to a first end of the lighting circuit, and as the first end of the driving circuit, is connected to a first end of the threshold setting circuit and a second end of the constant power compensation circuit; a second end of the DOB driving circuit is connected to a second end of the lighting circuit; a third end of the DOB driving circuit is connected to a first end of the adjustment circuit, and a fourth end of the DOB driving circuit is connected to a second end of the adjustment circuit;

[0026] The third terminal of the adjustment circuit serves as the second terminal of the driving circuit and is connected to the third terminal of the constant power compensation circuit.

[0027] Preferably, the DOB driving circuit includes: a driving chip, a rectifier, and a second MOS tube;

[0028] The first end of the rectifier is connected to the first pin of the driver chip, and together serves as the first end of the DOB driver circuit and is connected to the first end of the lighting circuit, the first end of the threshold setting circuit, and the second end of the constant power compensation circuit; the second end of the rectifier is connected to the neutral line of the mains; the third end of the rectifier is connected to the live line of the mains; the fourth end of the rectifier is connected to the second end of the driver chip and is grounded;

[0029] The third pin of the driver chip is connected to the gate of the second MOS tube; the fourth pin of the driver chip is connected to the second end of the adjustment circuit as the fourth end of the DOB driver circuit;

[0030] The drain of the second MOS tube is connected to the second end of the lighting circuit as the second end of the DOB driving circuit; the source of the second MOS tube is connected to the first end of the adjustment circuit as the third end of the DOB driving circuit and is grounded.

[0031] Preferably, the DOB driving circuit further comprises: a seventh resistor and an eighth resistor;

[0032] The first end of the seventh resistor is connected to the first end of the rectifier and serves as the first end of the DOB driving circuit and the first end of the lighting circuit; the second end of the seventh resistor is connected to the first pin of the driving chip;

[0033] The first end of the eighth resistor is connected to the source of the second MOS transistor, and together they serve as the third end of the DOB driving circuit connected to the first end of the adjustment circuit; the second end of the eighth resistor is grounded.

[0034] Preferably, the adjustment circuit includes: a ninth resistor and a tenth resistor;

[0035] The first end of the ninth resistor is connected to the third end of the DOB driving circuit as the first end of the adjustment circuit; the second end of the ninth resistor is connected to the first end of the tenth resistor, and together they serve as the third end of the adjustment circuit and are connected to the third end of the constant power compensation circuit;

[0036] The second end of the tenth resistor serves as the second end of the adjustment circuit and is connected to the fourth end of the DOB driving circuit.

[0037] In order to solve the above technical problems, the present application also provides an LED lamp, including the above constant power control circuit.

[0038] The present invention provides a constant power control circuit, comprising: a constant power compensation circuit, a transistor gate protection circuit, and a threshold setting circuit; wherein the first end of the threshold setting circuit is connected to the first end of the drive circuit, the first end of the transistor gate protection circuit is connected to the second end of the threshold setting circuit, the second end of the transistor gate protection circuit is connected to the third end of the threshold setting circuit, the third end of the transistor gate protection circuit is connected to the first end of the constant power compensation circuit, the second end of the constant power compensation circuit is connected to the first end of the threshold setting circuit and the first end of the drive circuit, and the third end of the constant power compensation circuit is connected to the second end of the drive circuit. The threshold setting circuit in the constant power control circuit provided by the present application obtains the driving voltage in the drive circuit and sets the starting voltage according to the driving voltage and its own structure; the transistor gate protection circuit obtains the starting voltage and reduces the starting voltage to prevent the starting voltage from damaging the constant power compensation circuit; the constant power compensation circuit compares the starting voltage with its own voltage threshold, and when the starting voltage is not less than the voltage threshold, the constant power compensation circuit starts to work, realizes power compensation, and thus achieves constant power output. BRIEF DESCRIPTION OF THE DRAWINGS

[0039] In order to more clearly illustrate the embodiments of the present invention, the following is a brief introduction to the drawings required for use in the embodiments. Obviously, the drawings described below are only some embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying any creative work.

[0040] Figure 1 A circuit diagram of a constant power control circuit provided in this application;

[0041] Figure 2 A circuit diagram of a complete constant power control circuit provided for the implementation of this application;

[0042] Figure 3 A schematic diagram of the circuit structure provided in an embodiment of the present application. DETAILED DESCRIPTION

[0043] The following will be combined with the accompanying drawings in the embodiments of the present invention to clearly and completely describe the technical solutions in the embodiments of the present invention. Obviously, the embodiments described are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without making creative efforts shall fall within the scope of protection of the present invention.

[0044] The core of the utility model is to provide a constant power control circuit and an LED lamp.

[0045] In order to enable those skilled in the art to better understand the present invention, the present invention will be described in further detail below with reference to the accompanying drawings and specific implementation methods.

[0046] This application provides a constant power control circuit, such as Figure 1 As shown, it includes: a constant power compensation circuit 1, a transistor gate protection circuit 2, a threshold setting circuit 3, and in addition, Figure 1 The device also includes a drive circuit 4. The circuit connections are as follows: a first terminal of a threshold setting circuit 3 is connected to a first terminal of the drive circuit 4, for obtaining a drive voltage from the drive circuit 4 and setting a startup voltage based on the drive voltage; a first terminal of a transistor gate protection circuit 2 is connected to a second terminal of the threshold setting circuit 3, a second terminal of the transistor gate protection circuit 2 is connected to a third terminal of the threshold setting circuit 3, and a third terminal of the transistor gate protection circuit 2 is connected to a first terminal of a constant power compensation circuit 1, for reducing the startup voltage; a second terminal of the constant power compensation circuit 1 is connected to a first terminal of the threshold setting circuit 3 and a first terminal of the drive circuit 4, and a third terminal of the constant power compensation circuit 1 is connected to a second terminal of the drive circuit 4; the constant power compensation circuit 1 is used to determine whether power compensation is achieved based on the relationship between the startup voltage and its own voltage threshold.

[0047] In a specific embodiment, the threshold setting circuit 3 is connected to the driving circuit 4 and obtains the voltage (driving voltage) at the first end of the driving circuit. The threshold setting circuit 3 sets a starting voltage according to the driving voltage and its own structure. The function of the starting voltage is to control the operation of the constant power compensation circuit 1; the transistor gate protection circuit 2 is connected to the threshold setting circuit 3 and the constant power compensation circuit 1, which is used to reduce the obtained starting voltage to prevent the starting voltage from damaging the constant power compensation circuit 1; and the constant power compensation circuit 1 is connected to the threshold setting circuit 1 and the driving circuit 4. The constant power compensation circuit 1 has an operating voltage, which is the voltage threshold. When the starting voltage is less than the voltage threshold, it means that the current constant power compensation circuit 1 does not need to work, and the entire circuit does not need to implement power compensation; when the starting voltage is not less than the voltage threshold, it means that the current overall voltage has increased, and the constant power compensation circuit 1 needs to work to reduce the power increase caused by the voltage increase, so as to keep the final output power constant.

[0048] Among them, it should be noted that the driving circuit 4 provided in this application is a conventional circuit, and the specifications can be selected according to the needs of the user; the constant power compensation circuit 1, transistor gate protection circuit 2, and threshold setting circuit 3 provided in this application only need to meet the corresponding functions of the circuit. The specific circuit structure is not limited in this application and can be set according to the needs of the user.

[0049] It can be seen from this that the threshold setting circuit in the constant power control circuit provided in the present application obtains the driving voltage in the driving circuit and sets the starting voltage according to the driving voltage and its own structure; the transistor gate protection circuit obtains the starting voltage and reduces the starting voltage to prevent the starting voltage from damaging the constant power compensation circuit; the constant power compensation circuit compares the starting voltage with its own voltage threshold. When the starting voltage is not less than the voltage threshold, the constant power compensation circuit starts working to achieve power compensation to achieve constant power output.

[0050] Based on the above embodiment, as a preferred embodiment, the threshold setting circuit 3 is as follows: Figure 2As shown, the circuit includes: a first voltage-stabilizing diode D1, a second voltage-stabilizing diode D2, a first resistor R1, a second resistor R2, and a first capacitor C1. The circuit connection relationship is as follows: the first end of the first voltage-stabilizing diode D1 is connected to the first end of the driving circuit 4 and the second end of the constant power compensation circuit 1 as the first end of the threshold setting circuit 3, and the second end of the first voltage-stabilizing diode D1 is connected to the first end of the second voltage-stabilizing diode D2; the second end of the second voltage-stabilizing diode D2 is connected to the first end of the first resistor R1; the second end of the first resistor R1 is connected to the first end of the second resistor R2 and the first end of the first capacitor C1, and together serve as the second end of the threshold setting circuit 3 and are connected to the first end of the transistor gate protection circuit 2; the second end of the second resistor R2 is connected to the first end of the first capacitor C1, and together serve as the third end of the threshold setting circuit 3 and are connected to the second end of the transistor gate protection circuit 2.

[0051] As a preferred embodiment, the transistor gate protection circuit 2 is as follows Figure 2 As shown, it includes: a third voltage-stabilizing diode D3, a third resistor R3, and a fourth resistor R4. The specific connection relationship is as follows: the first end of the third resistor R3 is connected to the second end of the threshold setting circuit 3 as the first end of the transistor gate protection circuit 2; the second end of the third resistor R3 is connected to the first end of the third voltage-stabilizing diode D3 and the first end of the fourth resistor R4, and together serve as the fourth end of the transistor gate protection circuit 2 and are connected to the first end of the constant power compensation circuit 1; the second end of the third voltage-stabilizing diode D3 and the second end of the fourth resistor R4 are connected, and together serve as the second end of the transistor gate protection circuit 2 and are connected to the third end of the threshold setting circuit 3, and are grounded.

[0052] As a preferred embodiment, the constant power compensation circuit 1 is as follows Figure 2 As shown, the circuit includes: a fifth resistor R5, a sixth resistor R6, and a first MOS transistor Q1. Specifically, the connection relationship is as follows: the first end of the fifth resistor R5, as the second end of the constant power compensation circuit 1, is connected to the first end of the threshold setting circuit 3 and the first end of the driving circuit 4; the second end of the fifth resistor R5 is connected to the first end of the sixth resistor R6; the second end of the sixth resistor R6 is connected to the drain of the first MOS transistor Q1; the gate of the first MOS transistor Q1, as the first end of the constant power compensation circuit 1, is connected to the third end of the transistor gate protection circuit 2; and the source of the first MOS transistor Q1, as the third end of the constant power compensation circuit, is connected to the second end of the driving circuit.

[0053] besides, Figure 2 The circuit also includes a second capacitor C2, which can be understood as a filter circuit. The specific connection relationship is: the first end of the second capacitor C2 is connected to the second end of the fifth resistor R5 and the first end of the sixth resistor R6, and the second end of the second capacitor C2 is grounded.

[0054] As a preferred embodiment, the specific structure of the driving circuit 4 is also as follows Figure 2 As shown, it includes: a DOB driving circuit 41, a lighting circuit 42 and an adjustment circuit 43. The specific connection relationship is: the first end of the DOB driving circuit 41 is connected to the first end of the lighting circuit 42, and is connected to the first end of the threshold setting circuit 3 and the second end of the constant power compensation circuit 1 as the first end of the driving circuit 4; the second end of the DOB driving circuit 41 is connected to the second end of the lighting circuit 42; the third end of the DOB driving circuit 41 is connected to the first end of the adjustment circuit 43, and the fourth end of the DOB driving circuit 41 is connected to the second end of the adjustment circuit 43; the third end of the adjustment circuit 43 is connected to the third end of the constant power compensation circuit 1 as the second end of the driving circuit 4. Figure 3 It can be seen that its overall structure includes: a constant power compensation circuit 1, a transistor gate protection circuit 2, a threshold setting circuit 3, a filter circuit 5, a DOB driving circuit 41, a lighting circuit 42 and an adjustment circuit 43.

[0055] Among them, such as Figure 2 As shown, the DOB driving circuit 41 includes: a driving chip U1, a rectifier DB1, a second MOS transistor Q2, a seventh resistor R7 and an eighth resistor R8. The specific connection relationship is as follows: the first end of the rectifier DB1 is connected to the first end of the seventh resistor R7, and together serves as the first end of the DOB driving circuit 41 and is connected to the first end of the lighting circuit 42, the first end of the threshold setting circuit 3 and the second end of the constant power compensation circuit 1; the second end of the rectifier DB1 is connected to the mains neutral line (AC-N); the third end of the rectifier DB1 is connected to the mains live line (AC-L); the fourth end of the rectifier DB1 is connected to the second end (GND) of the driving chip U1 , and grounded; the second end of the seventh resistor R7 is connected to the first pin (Vin) of the driver chip U1; the third pin (Gate) of the driver chip U1 is connected to the gate of the second MOS transistor Q2; the fourth pin (CS) of the driver chip U1 is connected to the second end of the adjustment circuit 43 as the fourth end of the DOB driver circuit 41; the drain of the second MOS transistor Q2 is connected to the second end of the lighting circuit 42 as the second end of the DOB driver circuit 41; the source of the second MOS transistor is connected to the first end of the eighth resistor R8, and together they serve as the third end of the DOB driver circuit 41 and are connected to the first end of the adjustment circuit 43; the second end of the eighth resistor R8 is grounded.

[0056] Among them, the adjustment circuit includes: a ninth resistor R9 and a tenth resistor R10, and the specific connection relationship is: the first end of the ninth resistor R9 is connected to the third end of the DOB drive circuit 41 as the first end of the adjustment circuit 43; the second end of the ninth resistor R9 is connected to the first end of the tenth resistor R10, and together serve as the third end of the adjustment circuit 43 and are connected to the third end of the constant power compensation circuit 3; the second end of the tenth resistor R10 is connected to the fourth end of the DOB drive circuit 41 as the second end of the adjustment circuit 43.

[0057] In addition, the lighting circuit 42 includes four LEDs, namely LED1, LED2, LED3, and LED4, and their connection relationship is: the first end of LED1 is connected to the first end of the DOB drive circuit 41 as the first end of the lighting circuit 42, and the second end of LED1 is connected to the first end of LED2; the second end of LED2 is connected to the first end of LED3; the third end of LED3 is connected to the first end of LED4; the second end of LED4 is connected to the second end of the DOB drive circuit 41 as the second end of the lighting circuit 42.

[0058] The operating principle of the complete constant power control circuit is as follows: the threshold setting circuit 3 obtains the driving voltage Va. When the driving voltage Va increases and reaches the breakdown voltage of the first and second voltage-stabilizing diodes D1 and D2, the two voltage-stabilizing diodes conduct and divide a portion of the fixed voltage (VD1 + VD2, where VD1 is the stable voltage of the first voltage-stabilizing diode D1 and VD2 is the stable voltage of the second voltage-stabilizing diode D2). As the driving voltage Va continues to rise, the startup voltage Vc formed by the voltage divider between the first and second resistors R1 and R2 also increases. The transistor gate protection circuit 2 obtains the startup voltage Vc. At this time, the third and fourth resistors R3, R4, and the third voltage-stabilizing diode D3 form a voltage-stabilizing circuit to ensure that the startup voltage Vc does not break down the first MOS transistor Q1. The threshold setting circuit 3 and the constant power compensation circuit 1 have the following relationship:

[0059] (1) When Vc < Vgs*(R3+R4) / R3, the first MOS tube Q1 is not conducting; the constant power compensation circuit 1 does not work;

[0060] (2) When Vc=Vgs*(R3+R4) / R3, the conduction threshold of the first MOS tube Q1 is just reached, and the constant power compensation circuit 1 starts to work;

[0061] (3) When Vc>Vgs*(R3+R4) / R3, the first MOS tube Q1 continues to be turned on and the constant power compensation circuit 1 continues to work.

[0062] Wherein, R3 is the resistance value of the third resistor R3, R4 is the resistance value of the fourth resistor R4, and Vgs*(R3+R4) / R3 is the voltage threshold.

[0063] After processing by the constant power compensation circuit 1, the voltage Vs at the connection point between the first MOS transistor Q1 and the eighth resistor R8 decreases. According to the current sampling formula I=Vs / R8 (R8 is the resistance value of the eighth resistor R8), the driver chip U1 will reduce the duty cycle of the output of the third pin (Gate), thereby reducing the system current, that is, reducing the system power, thereby offsetting the power increase and achieving constant power control.

[0064] The design principle of the transistor gate protection circuit is as follows: the impedance between the gate and source of the first MOS transistor Q1 is high. A sudden voltage change between the drain and source of the first MOS transistor Q1 will be coupled to the gate of the first MOS transistor Q1 through the inter-electrode capacitance, generating a very high gate-source spike voltage. This voltage can cause the very thin gate-source oxide layer to breakdown. At the same time, the gate of the first MOS transistor Q1 easily accumulates charge, which can also cause the gate-source oxide layer to breakdown. Therefore, a third voltage regulator D3 is connected in parallel with the gate of the first MOS transistor Q1. The third voltage regulator D3 can limit the gate voltage of the first MOS transistor Q1 to below the regulated voltage value of the third voltage regulator D3, protecting the first MOS transistor Q1 from breakdown. A fourth resistor R4 is connected in parallel with the gate of the first MOS transistor Q1 to release the gate charge of the first MOS transistor Q1, preventing charge accumulation and avoiding malfunction of the first MOS transistor Q1, which may cause conduction.

[0065] The design principle of the constant power compensation circuit 1 is as follows: when setting the system's initial power, the first MOS transistor Q1 in the constant power compensation circuit is in an off state, and the circuit is not currently collecting constant power compensation signals. Therefore, the voltage Vb at the connection between the constant power compensation circuit 1 and the driver circuit 4 is not affected (where Vb is related to the fifth resistor R5 and the sixth resistor R6), and the value of the eighth resistor R8 in the DOB driver circuit 41 is also unaffected. In this configuration, the initial power setting is not affected. If the first MOS transistor Q1 remains on, the circuit continues to collect constant power compensation signals. This affects the voltage Vb, causing it to decrease, thereby reducing the voltage Vs at the connection between the first MOS transistor Q1 and the eighth resistor R8, ultimately affecting the value of the eighth resistor R8. This situation affects the initial system power setting. To ensure the desired system power value, a smaller eighth resistor R8 should be selected. However, this situation has a drawback. When constant power compensation circuit 1 is damaged or opens, voltage Vb and voltage Vs return to their initial states, while the value of eighth resistor R8 is already smaller. According to the voltage-current equation (I = Vs / R8), the overall system current increases, which in turn increases the system power. Therefore, it is necessary to determine whether the first MOS transistor Q1 in constant power compensation circuit 1 is conducting based on the startup voltage in threshold setting circuit 3 and the voltage threshold in constant power compensation circuit 1, and then adjust voltage Vs to achieve constant power control.

[0066] It should be noted that the specific structure of the constant power compensation circuit 1, transistor gate protection circuit 2, threshold setting circuit 3 and drive circuit 4 provided in this application is only one possible implementation method, but is not limited to only this implementation method and can be set according to user needs.

[0067] It can be seen from this that the threshold setting circuit in the constant power control circuit provided in the present application obtains the driving voltage in the driving circuit and sets the starting voltage according to the driving voltage and its own structure; the transistor gate protection circuit obtains the starting voltage and reduces the starting voltage to prevent the starting voltage from damaging the constant power compensation circuit; the constant power compensation circuit compares the starting voltage with its own voltage threshold. When the starting voltage is not less than the voltage threshold, the constant power compensation circuit starts working to achieve power compensation to achieve constant power output.

[0068] In order to solve the above technical problems, the present application also provides an LED lamp, including the above constant power control circuit, and has the same beneficial effects. The specific embodiments are the same as the embodiments of the above constant power control circuit, and this application will not go into details here.

[0069] The above is a detailed introduction to a constant power control circuit and LED lamp provided by the present invention. The various embodiments in the specification are described in a progressive manner, and each embodiment focuses on the differences from other embodiments. The same and similar parts between the various embodiments can be referred to each other. For the device disclosed in the embodiment, since it corresponds to the method disclosed in the embodiment, the description is relatively simple, and the relevant parts can be referred to the method part description. It should be pointed out that for ordinary technicians in this technical field, without departing from the principle of the present invention, the present invention can also be improved and modified in several ways, and these improvements and modifications also fall within the scope of protection of the claims of the present invention.

[0070] It should also be noted that, in this specification, relational terms such as first and second, etc., are used only to distinguish one entity or operation from another entity or operation, and do not necessarily require or imply any such actual relationship or order between these entities or operations. Moreover, the terms "comprises," "comprising," or any other variants thereof are intended to cover non-exclusive inclusion, such that a process, method, article, or apparatus comprising a series of elements includes not only those elements, but also other elements not explicitly listed, or elements inherent to such process, method, article, or apparatus. In the absence of further limitations, an element defined by the phrase "comprising a ..." does not exclude the presence of additional identical elements in the process, method, article, or apparatus comprising the element.

Claims

1. A constant power control circuit, characterized in that: include: Constant power compensation circuit, transistor gate protection circuit, threshold setting circuit; Wherein, the first terminal of the threshold setting circuit is connected to the first terminal of the driving circuit, and is used to obtain the driving voltage in the driving circuit and set the starting voltage according to the driving voltage; The first end of the transistor gate protection circuit is connected to the second end of the threshold setting circuit, the second end of the transistor gate protection circuit is connected to the third end of the threshold setting circuit, and the third end of the transistor gate protection circuit is connected to the first end of the constant power compensation circuit, for reducing the startup voltage; The second end of the constant power compensation circuit is connected to the first end of the threshold setting circuit and the first end of the drive circuit, and the third end of the constant power compensation circuit is connected to the second end of the drive circuit; it is used to determine whether power compensation is achieved based on the size relationship between the starting voltage and its own voltage threshold.

2. The constant power control circuit according to claim 1, characterized in that: The threshold setting circuit includes: a first voltage-stabilizing diode, a second voltage-stabilizing diode, a first resistor, a second resistor and a first capacitor; Wherein, the first end of the first voltage regulator tube is connected to the first end of the driving circuit and the second end of the constant power compensation circuit as the first end of the threshold setting circuit, and the second end of the first voltage regulator tube is connected to the first end of the second voltage regulator tube; The second end of the second voltage regulator tube is connected to the first end of the first resistor; The second end of the first resistor is connected to the first end of the second resistor and the first end of the first capacitor, and together serve as the second end of the threshold setting circuit and are connected to the first end of the transistor gate protection circuit; The second end of the second resistor and the first end of the first capacitor are connected to each other, and together serve as the third end of the threshold setting circuit and are connected to the second end of the transistor gate protection circuit.

3. The constant power control circuit according to claim 1, characterized in that: The transistor gate protection circuit includes: a third voltage regulator tube, a third resistor and a fourth resistor; The first end of the third resistor serves as the first end of the transistor gate protection circuit and is connected to the second end of the threshold setting circuit; the second end of the third resistor is connected to the first end of the third voltage regulator tube and the first end of the fourth resistor, and together serve as the fourth end of the transistor gate protection circuit and are connected to the first end of the constant power compensation circuit; The second end of the third voltage regulator tube and the second end of the fourth resistor are connected, and together serve as the second end of the transistor gate protection circuit, connected to the third end of the threshold setting circuit, and grounded.

4. The constant power control circuit according to any one of claims 1 to 3, characterized in that: The constant power compensation circuit includes: a fifth resistor, a sixth resistor and a first MOS tube; The first end of the fifth resistor is connected to the first end of the threshold setting circuit and the first end of the driving circuit as the second end of the constant power compensation circuit, and the second end of the fifth resistor is connected to the first end of the sixth resistor; The second end of the sixth resistor is connected to the drain of the first MOS transistor; The gate of the first MOS transistor is connected to the third end of the transistor gate protection circuit as the first end of the constant power compensation circuit, and the source of the first MOS transistor is connected to the second end of the drive circuit as the third end of the constant power compensation circuit.

5. The constant power control circuit according to claim 4, characterized in that: Also includes: a second capacitor; The first end of the second capacitor is connected to the second end of the fifth resistor and the first end of the sixth resistor, and the second end of the second capacitor is grounded.

6. The constant power control circuit according to any one of claims 1 to 5, characterized in that: The driving circuit includes: a DOB driving circuit, a lighting circuit and an adjustment circuit; Wherein, the first end of the DOB driving circuit is connected to the first end of the lighting circuit, and is connected as the first end of the driving circuit to the first end of the threshold setting circuit and the second end of the constant power compensation circuit; the second end of the DOB driving circuit is connected to the second end of the lighting circuit; the third end of the DOB driving circuit is connected to the first end of the adjustment circuit, and the fourth end of the DOB driving circuit is connected to the second end of the adjustment circuit; The third end of the adjustment circuit serves as the second end of the drive circuit and is connected to the third end of the constant power compensation circuit.

7. The constant power control circuit according to claim 6, characterized in that: The DOB driving circuit includes: a driving chip, a rectifier, and a second MOS tube; The first end of the rectifier is connected to the first pin of the driver chip, and together serves as the first end of the DOB driver circuit and is connected to the first end of the lighting circuit, the first end of the threshold setting circuit, and the second end of the constant power compensation circuit; the second end of the rectifier is connected to the neutral line of the mains; the third end of the rectifier is connected to the live line of the mains; the fourth end of the rectifier is connected to the second end of the driver chip and is grounded; The third pin of the driver chip is connected to the gate of the second MOS transistor; the fourth pin of the driver chip serves as the fourth end of the DOB driver circuit and is connected to the second end of the adjustment circuit; The drain of the second MOS transistor is connected to the second end of the lighting circuit as the second end of the DOB driving circuit; the source of the second MOS transistor is connected to the first end of the adjustment circuit as the third end of the DOB driving circuit and is grounded.

8. The constant power control circuit according to claim 7, characterized in that: The DOB driving circuit further includes: a seventh resistor and an eighth resistor; The first end of the seventh resistor is connected to the first end of the rectifier and serves as the first end of the DOB driving circuit and the first end of the lighting circuit; the second end of the seventh resistor is connected to the first pin of the driving chip; A first end of the eighth resistor is connected to the source of the second MOS transistor, and together serves as the third end of the DOB driving circuit connected to the first end of the adjustment circuit; a second end of the eighth resistor is grounded.

9. The constant power control circuit according to claim 6, characterized in that: The adjustment circuit includes: a ninth resistor and a tenth resistor; The first end of the ninth resistor is connected to the third end of the DOB driving circuit as the first end of the adjustment circuit; the second end of the ninth resistor is connected to the first end of the tenth resistor, and together serve as the third end of the adjustment circuit and are connected to the third end of the constant power compensation circuit; The second end of the tenth resistor serves as the second end of the adjustment circuit and is connected to the fourth end of the DOB driving circuit.

10. An LED lamp, characterized in that: The invention comprises the constant power control circuit according to any one of claims 1 to 9.

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