An LED power supply

Abstract

The present invention discloses an LED power supply, which includes a circuit board assembly. A high-voltage input end, a rectification and filtering circuit, a drive control module, a step-down transformer, a DC-DC circuit, and an LED connection end are sequentially electrically connected on the circuit board assembly. The drive control module at least includes a control unit and a switching unit. The circuit board assembly includes a main board and at least one first sub-board that is electrically connected to the main board and perpendicular to each other. The drive control module is provided on the first sub-board. For the LED power supply of the present invention, the circuit board is modularized in the form of an inserted board, and the electronic components are arranged three-dimensionally. The dimensions between the components are compact, which can greatly reduce the overall size of the product and meet the requirements of product miniaturization.

Description

Technical Field

[0001] The present invention relates to the technical field of driving power supplies, and particularly to an LED power supply. Background Art

[0002] An LED power supply is a type of driving power supply. Miniaturization is the development direction of LED power supplies. The miniaturization of LED power supplies poses a greater challenge to electromagnetic compatibility (EMC) design compared to ordinary power supplies, especially for dimmable power supplies, because their operating states and frequencies vary significantly between full power and dimming or light load and low power. The operating frequency ranges of general EMC inductors and capacitors are relatively fixed, making EMC design difficult.

[0003] In addition, for compact LED power supplies, in order to solve the heat dissipation problem of power devices, potting is generally used. However, potting adhesives all have a certain dielectric constant, which reduces the EMC performance of the product. Conventional treatment methods: To pass the EMC test standard, filter inductors and filter capacitors are added or enlarged at the input and output lines of the circuit. At the same time, the distance between the switching power device and the EMC device can also be increased to suppress high-frequency electromagnetic waves, or a metal shielding cover can be used. The disadvantage of this is that the cost of the product will increase significantly, the complexity of the production process will increase, and the product size needs to be enlarged, making it difficult to make it small and unable to meet market demand. Summary of the Invention

[0004] In view of this, the present invention provides an LED power supply to solve the above technical problems.

[0005] An LED power supply includes a circuit board assembly. The circuit board assembly is provided with a high-voltage input terminal, a rectification and filtering circuit, a drive control module, a step-down transformer, a DC-DC circuit, and an LED connection terminal that are electrically connected in sequence. The drive control module includes at least a control unit and a switching unit. The circuit board assembly includes a main board and at least one first sub-board that is electrically connected to the main board and perpendicular to it. The drive control module is provided on the first sub-board.

[0006] Preferably, the circuit board assembly includes a second sub-board that is electrically connected to the main board and perpendicular to it. The DC-DC circuit is provided on the second sub-board.

[0007] Preferably, the DC-DC circuit is electrically connected to a dimming control module. The dimming control module and the DC-DC circuit are arranged on the same sub-board.

[0008] Preferably, the rectification and filtering circuit is provided on the main board. The rectification and filtering circuit includes a plurality of EMC devices.

[0009] Preferably, a metal shielding tape is provided on the first daughter board around the switch unit, and the metal shielding tape is grounded.

[0010] Preferably, the metal shielding tape is single-sided.

[0011] Preferably, at least part of the metal shielding tape is double-sided, and the double-sided area is provided with metallized vias for conduction.

[0012] Preferably, the metal shielding tape at least includes a first section extending outward from a position close to the main board. The first section is located on one side close to the edge of the first daughter board and is at least flush with the upper edge of the switch unit.

[0013] Preferably, the switch unit uses a MOS transistor.

[0014] Preferably, the metal shielding tape further includes a second section connecting to the end of the first section and continuing to be arranged around the switch unit.

[0015] Technical effects of the present invention:

[0016] The LED power supply of the present invention modularizes the circuit board in the form of an inserted board, and the electronic components are three-dimensionally arranged. The sizes between the components are compact, which can greatly reduce the overall size of the product and meet the requirements of product miniaturization; a metal shielding tape is arranged on the outer periphery of the switch unit, so that part of the electromagnetic interference generated by the switch unit is introduced into the ground wire through the metal shielding tape, reducing the interference to other EMC components. Especially for products with potting, a certain degree of shielding effect can be achieved, meeting the requirements of electromagnetic compatibility standards. Its production process is simple, and because the capacitance values of other filtering capacitors and other components can be correspondingly reduced, components with a smaller package size can be selected, saving product costs while reducing the occupied space size of the components. Description of the drawings

[0017] The embodiments of the present invention are described below in conjunction with the drawings, where:

[0018] Figure 1 is the structural block diagram of the LED power supply of this embodiment.

[0019] Figure 2 is the structural block diagram of the drive control module of this embodiment.

[0020] Figure 3 is the circuit schematic diagram of the LED power supply of this embodiment.

[0021] Figure 4 is the structural schematic diagram of the circuit board assembly of this embodiment.

[0022] Figure 5 is the three-dimensional structural schematic diagram of the circuit board assembly of this embodiment.

[0023] Figure 6 It is a schematic structural diagram of the first daughter board of this embodiment.

[0024] Figure 7 It is a schematic structural diagram of the back of the first daughter board of this embodiment.

[0025] Figure 8 It is a schematic structural diagram of the first daughter board of another embodiment.

[0026] Figure 9 It is a schematic structural diagram of the first daughter board of another embodiment.

[0027] Figure 10 It is a schematic structural diagram of the first daughter board of another embodiment.

[0028] Figure 11 It is a schematic structural diagram of the back of the first daughter board of another embodiment. Detailed implementation manners

[0029] The following further details the specific embodiments of the present invention based on the accompanying drawings. It should be understood that the description of the embodiments of the present invention herein does not limit the protection scope of the present invention.

[0030] As Figures 1 to 7 shown, the LED power supply of this embodiment includes a circuit board assembly 100, and a high-voltage input terminal 200, a rectification and filtering circuit 300, a drive control module 400, a step-down transformer 500, a DC-DC circuit 600, and an LED connection terminal 700 which are electrically connected in sequence are provided on the circuit board assembly 100. The power supply of the present invention uses a printed circuit board to realize the electrical connection of the electronic components of each module and circuit. How to arrange the above modules and circuits on the circuit board is the prior art and will not be elaborated.

[0031] In the LED power supply of the prior art, the above high-voltage input terminal 200, rectification and filtering circuit 300, drive control module 400, step-down transformer 500, DC-DC circuit 600, and LED connection terminal 700 are included. The specific circuit and the mutual connection manner are the prior art, and the existing circuits can be adopted and will not be elaborated.

[0032] The LED power supply further includes a housing for arranging the circuit board assembly 100, which is the prior art and will not be elaborated.

[0033] The drive control module 400 includes at least a control unit 401 and a switch unit 402. The circuit board assembly 100 includes a main board 101 and at least one first sub-board 102 that is electrically connected to the main board 101 and perpendicular to each other. The drive control module 400 is provided on the first sub-board 102, and electrical connection is achieved by means of plug-in boards, which facilitates the realization of automated production, and the perpendicular arrangement realizes a three-dimensional layout.

[0034] The circuit board assembly 100 includes a second sub-board 103 that is electrically connected to the main board 101 and perpendicular to each other. A DC-DC circuit 600 is provided on the second sub-board 103.

[0035] The DC-DC circuit 600 is electrically connected to a dimming control module 800, and the dimming control module 800 and the DC-DC circuit 600 are arranged on the same sub-board 102.

[0036] Among them, the first sub-board 102 and the second sub-board 103 can adopt the double-sided SMT process, and the production process is simple. On the premise of realizing the product functions, the miniaturization requirements are met.

[0037] The switch unit 401 of the LED power supply has a relatively high operating frequency, which will generate electromagnetic wave interference such as switching oscillation and multiple high-frequency harmonics, and will have an adverse impact on the surrounding electrical appliances and environment. And electronic products need to meet the domestic and international test standards for electromagnetic compatibility before they can enter the application market. Therefore, it is necessary to carry out compliance design for the electromagnetic compatibility of the product, design filter devices and circuits dedicated to electromagnetic compatibility. In order to eliminate the above problems, the rectifier filter circuit 300 is provided on the main board 101, and the rectifier filter circuit 300 includes a plurality of EMC devices.

[0038] The core of the switching power supply is the switch unit 401, that is, the power switching device. The switch unit 401 generates a large amount of high-frequency electromagnetic interference when it is switched. The high-frequency electromagnetic interference generated must be suppressed by EMC devices such as C101, C102, L101, L102 (not shown in the figure) on the rectifier filter circuit 300. The specific types and quantities of EMC devices can be selected according to needs. Only a demonstration is given in this embodiment. Through the above settings, electromagnetic interference is reduced. However, when the product size is small, the distances between the switch unit 401 and the EMC devices are very close, which will directly affect the effect of the electromagnetic compatibility circuit. Especially when the LED power supply has a dimming circuit working, the switching frequency changes in a large range, and it is very difficult for the electromagnetic compatibility circuit to meet the standard requirements, especially the average value limit curve in the intermediate frequency band of 200K~1000KHz of the conduction test, and the impact is particularly large and it is very difficult to pass.

[0039] In the prior art, there is a metal shielding cover solution. For example, a ground metal shielding cover can be used on the first daughter board 102 where the switch unit 401 is located to reduce electromagnetic interference. However, the process is relatively complex, which is not conducive to mass production, and the overall cost will also increase significantly.

[0040] This embodiment is an improved electromagnetic compatibility design for the switch unit 401. A ground metal shielding band 1021 is added at a position close to the EMC device. The metal shielding band 1021 is provided on the first daughter board 102 and is arranged around the switch unit 402, and the metal shielding band 1021 is grounded.

[0041] The metal shielding band 1021 can be single-sided. To improve the effect, it can be arranged on both sides, that is, copper foil and metallized vias can be directly used on a double-sided circuit board. Part of the electromagnetic interference generated by the switch unit 402 is introduced into the ground wire through the metal shielding band 1021, reducing the interference to other EMC devices. Especially for products with potting, a certain degree of shielding effect can be achieved, meeting the requirements of electromagnetic compatibility standards. Its production process is simple, and since the capacitance values of other filter capacitors and other devices can be reduced accordingly, devices with a smaller package size can be selected, saving product costs while reducing the occupied space size of components. In this embodiment,

[0042] The metal shielding band 1021 of this embodiment includes a first section 1023 extending outward from a position close to the main board 101. The first section 1023 is located on one side close to the edge of the first daughter board 102 and crosses the upper edge 4021 of the switch unit 402. The first section 1023 of the metal shielding band 1021 is double-sided, and a metallized via 1022 is provided in the double-sided arranged area for conduction. The metal shielding band 1021 of this embodiment further includes a second section 1024 connected to the end of the first section 1023 and continuing to be arranged around the switch unit 402. The second section 1024 is single-sided. Generally, as long as there is enough area on the back, it will be arranged on both sides because the shielding effect of both sides is better. However, due to insufficient circuit layout positions, the second section 1024 can be selected according to needs.

[0043] As Figure 8 shown, in another embodiment, only the first section 1023 is provided and it is single-sided.

[0044] As Figure 9 shown, in another embodiment, the first section 1023 and the second section 1024 are provided and they are single-sided.

[0045] As Figure 10 and 11As shown, in another embodiment, there are provided the first section 1023 and the second section 1024. The first section 1023 is double-sided, and the front section of the second section 1024 is also double-sided while the rear section is single-sided, and the rear section of the second section 1024 is grounded.

[0046] The switching unit 402 is a power switching tube device. In this embodiment, an MOS tube is adopted, and a triode can also be used.

[0047] Through the above settings, the distance between the EMC device closest to the first daughter board 102 in the rectifying and filtering circuit 300 and the first daughter board 102 can be less than 5 mm, making the overall circuit board assembly 100 more compact.

[0048] The above are only the preferred embodiments of the present invention and are not used to limit the protection scope of the present invention. Any modifications, equivalent replacements or improvements within the spirit of the present invention are covered within the scope of the claims of the present invention.

Claims

1. An LED power supply, characterized in that, It includes a circuit board assembly (100). On the circuit board assembly (100), there are a high-voltage input terminal (200), a rectifying and filtering circuit (300), a drive control module (400), a step-down transformer (500), a DC-DC circuit (600), and an LED connection terminal (700) that are electrically connected in sequence. The circuit board assembly (100) includes a main board (101) and at least one first sub-board (102) that is electrically connected to the main board (101) and perpendicular to each other. On the main board, there is the rectifying and filtering circuit (300), and the rectifying and filtering circuit (300) includes a plurality of EMC devices. On the first sub-board (102), there is the drive control module (400). The drive control module (400) at least includes a control unit (401) and a switching unit (402). On the first sub-board (102), there is a metal shielding tape (1021) arranged around the switching unit (402). The metal shielding tape (1021) is a copper foil. The metal shielding tape (1021) at least includes a first section (1023) extending outward from a position close to the main board (101). The first section (1023) of the metal shielding tape (1021) is double-sided, with the two sides located on the front and back of the first sub-board respectively. There are metallized vias (1022) on the double-sided metal shielding tape for conduction. The metal shielding tape (1021) further includes a second section (1024) connecting to the end of the first section (1023) and continuing to be arranged around the switching unit (402). The second section (1024) of the metal shielding tape (1021) is grounded.

2. The LED power supply according to claim 1, wherein The circuit board assembly (100) includes a second sub-board (103) that is electrically connected to the main board (101) and perpendicular to each other. On the second sub-board (103), there is a DC-DC circuit (600).

3. The LED power supply according to claim 2, wherein The DC-DC circuit (600) is electrically connected to a dimming control module (800). The dimming control module (800) and the DC-DC circuit (600) are arranged on the same sub-board (102).

4. The LED power supply according to claim 1, characterized in that The second section of the metal shielding tape (1021) includes a single side.

5. The LED power supply according to claim 1, characterized in that, The metal shielding tape (1021) at least includes a first section (1023) extending outward from a position close to the main board (101). The first section (1023) is located on one side close to the edge of the first sub-board (102) and is at least flush with the upper edge (4021) of the switching unit (402).

6. The LED power supply according to any one of claims 1 to 5, characterized in that, The switching unit (402) uses a MOS transistor.

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