JPH0611331U - Choke coil for noise filter - Google Patents

Abstract

(57) [Abstract] [Purpose] A noise filter formed of two normal choke coils inserted in a power supply line and one common mode choke coil has a small board mounting area and a small number of components. Use choke coil for filter. [Composition] A common mode choke coil 1 having a frame shape having a high relative permeability characteristic on the outer periphery, in which two windings of a power supply wire are differentially wound on both magnetic legs of an annular closed magnetic circuit core 1c, and a common mode choke. Inside the coil 1, a power supply wire is wound around a dust core 2c or a magnetic core with a gap to form normal mode choke coils 2a and 2b, and the normal mode choke coils 2a and 2b are housed in a case 5 to accommodate the input / output side and the common mode choke coil. The choke coil is housed in a case 5 in which pin terminals are attached to the terminals between the mode choke coils, and resin molding is performed.

Description

[Detailed description of the device]

[0001]

[Industrial applications]

 The present invention relates to a choke coil for a noise filter mounted on an electronic device to suppress electromagnetic noise.

[0002]

[Prior art]

 As shown in FIG. 4, the conventional noise filter inserted in the power supply line is the normal mode choke coils 2a and 2b inserted in series in the power supply lines 3 and 4, and the power supply line is connected to the annular magnetic core. This is a combination of a common mode choke coil 1a in which windings are wound so that the magnetic fluxes generated in the magnetic core due to the reciprocating current flowing in the coil cancel each other out. There were drawbacks such as an increase in the number of component parts and an increase in the occupied area on the printed circuit board to be mounted.

[0003]

[Problems to be solved by the device]

 In order to solve these problems, the present invention arranges a ring-shaped closed magnetic circuit magnetic core having a high relative magnetic permeability characteristic on the outer periphery, and the magnetic fluxes produced by the currents reciprocating the power supply lines to the opposing magnetic legs, The magnetic fluxes generated in the ring-shaped closed magnetic circuit core are wound in directions that cancel each other out, and inside the frame-shaped ring-shaped closed magnetic circuit core, two powder magnetic cores formed in the shape of a frame are formed of metal magnetic powder having high relative magnetic permeability characteristics. Each power line is wound around each of the two normal mode choke coils, and the two normal mode chokes are sized so that they can be stored inside the common choke, and one wire of the normal mode choke coil and the common choke is connected in series. The normal mode choke coil 2 is simply connected to the power supply line on the board by connecting the pin terminals attached to the case to the case when mounting it on the board. And an object thereof is to provide a choke coil for noise filtering forming a common mode choke coil 1 of the noise filter.

[0004]

[Means for Solving the Problems] A ring-shaped closed magnetic circuit magnetic core is arranged in a frame shape having high relative magnetic permeability characteristics on the outer circumference, and two powder magnetic cores made of a frame-shaped metal magnetic powder are housed inside the two magnetic cores. Each of the dust cores is wound with a parallel wire of a power source wire to form a normal choke coil, and the magnetic fields created by the reciprocating power supply line currents cancel each other out on the outer peripheral frame-shaped closed magnetic circuit core. Each of the magnetic legs is wound with a power source wire to form a common mode choke coil. The normal mode choke coil is housed inside the common choke coil on both sides of the partition plate that separates the two normal mode choke coils in the center of the common choke coil. The common mode choke coil and the normal mode choke coil are mounted on the board. The pin terminals are housed in a case that has been planted in each of them, and lead wires are connected and soldered to each pin terminal. Common mode choke coils and normal mode choke coils are filled with embedded resin and fixed together. Therefore, when constructing a noise filter, use a choke coil for noise filter that can easily form a noise filter on the substrate simply by connecting a capacitor or a fixed resistor to each pin terminal.

That is, according to the present invention, two power supply lines are differentially wound with the same number of windings on both side magnetic legs of a ring-shaped closed magnetic circuit core in a frame shape having a high relative magnetic permeability characteristic on the outer periphery. A common mode choke coil and a normal mode choke in which one of two power supply wires is wound around two powder magnetic cores that fit inside the common mode choke coil are connected to the common mode choke coil wire and the normal mode choke coil. This is a choke coil for noise filters, characterized in that the wires of the mode choke coil are connected in series and housed in a case with pin terminals attached to the lower surface of the board mounting surface and filled with resin.

[0006]

[Action]

 The arrangement of one common mode choke coil and two normal mode choke coils and the windings are arranged symmetrically, and since each choke coil has a close contact structure, noise generated by external radiated radio waves is not generated. The impact is small. Since pin terminals are provided between the input / output sides of the normal mode choke coil and the common mode choke coil, and between the normal mode choke coil and the common mode choke coil, it is only necessary to connect a capacitor or fixed resistor to the pin terminals. It is possible to easily configure a noise filter in which two types of filters, i.e., .pi. Type, and inverted L type are cascade-connected.

[0007]

【Example】

 A choke coil for a noise filter according to the present invention will be described with reference to the drawings. FIG. 1 is a plan view showing a magnetic core and a winding of a noise filter choke coil according to the present invention. The outer periphery has a frame shape and uses a magnetic core having a high relative magnetic permeability characteristic of Mn-Zn ferrite or Ni-Zn ferrite having a high initial relative magnetic permeability, which is the inner side of the circular closed magnetic circuit core 1c. A frame-shaped dust core 2c made of metal magnetic powder of the same size and the same material, or a magnetic core having a void in the magnetic path of a ferrite core, is arranged in the. The powder magnetic core 2c is formed by winding the normal choke coils 2a and 2b, and each winding of the power supply line is wound around the magnetic path to form the normal choke coils 2a and 2b. To do. A power supply line through which a reciprocating current flows is wound around each of the magnetic legs on both sides of the ring-shaped closed magnetic circuit core 1c by a required number of turns. However, the windings of the normal mode choke coil 2a on the input side wires of the power supply lines 3 and 4 are connected in series to the respective windings of the common mode choke coil 1, and the windings of the other nor mode choke coil 2b are common. It is connected to the other winding of the mode choke coil 1. FIG. 1 shows an assembly of choke coils including normal mode choke coils 2a and 2b which are respectively connected in series to two power supply lines and a common mode choke coil 1 which is connected in series to a power supply line. After the two normal mode choke coils 2a and 2b and one common mode choke coil 1 shown in FIG. 1 are wound, they are housed in a case 5 shown in FIG. 2 and a power supply line is provided between the two normal mode choke coils. A partition plate 6 is inserted in order to ensure electrical insulation characteristics between them, and the whole surface of the wound choke coil is injected and impregnated with resin to be fixed. As shown in FIG. 3, pin terminals 11c are attached to the lower surface of the case 5 on the input and output sides of the power supply line, and to the power supply lines between the pin terminals 11a and 11b and the normal mode choke coil and the common mode choke coil. . A T-type, π-type, and inverse L-type filter can be configured by the configuration of the capacitor and the fixed resistor connected to the pin terminals, and the noise filter choke coil of the present invention can configure the cascade connection circuit of the noise filter. In addition, the surface of each magnetic core is coated with an electrically insulating coating when the winding is wound, or a coil bobbin with a structure that can be installed in the magnetic leg divided in the direction of the magnetic leg is installed in the magnetic leg to The choke coil winding is wound while ensuring the electrical withstand voltage characteristic with the winding.

[0008]

[Effect of device]

 The frame-shaped annular closed magnetic circuit core according to the present invention, and two powder magnetic cores housed inside the annular closed magnetic circuit magnetic core, the winding is wound around the powder magnetic core to form the normal mode choke coil into the annular closed magnetic circuit magnetic core. A common mode choke coil is formed by winding the power supply line differentially to form one common mode choke coil and two normal mode choke coils. Each input / output side, normal mode choke coil and common mode choke The pin terminals are pulled out from the middle of the coil so that they can be mounted on the board. Also, by using a choke coil for noise filter that is housed in the case and integrally molded with resin, each of the three conventional choke coils can be used. An inexpensive choke coil for a noise filter that occupies a small board mounting area and reduces the number of parts used for each choke coil. There can be provided.

[Brief description of drawings]

FIG. 1 is a plan view showing an arrangement of a choke coil for a noise filter according to the present invention.

FIG. 2 is an external perspective view of the choke coil for a noise filter according to the present invention, which is housed in the choke coil and is not resin-molded.

FIG. 3 is a pin terminal arrangement diagram on a board mounting side.

FIG. 4 is a diagram showing an arrangement of a noise filter, a normal mode choke coil, and a common mode choke coil.

[Explanation of symbols]

 1, 1a Common mode choke coil 1c Annular closed magnetic circuit magnetic core 2, 2a, 2b Normal mode choke coil 2c Powder magnetic core 3, 4 Power supply wire 5 Case 6 Partition plate 7, 8 Tsuba 9, 10 Winding 11a, 11b, 11c Pin Terminal

Claims (1)

[Scope of utility model registration request] 1. A common mode choke in which two power supply lines are differentially wound with the same number of windings on both side magnetic legs of a ring-shaped closed magnetic circuit core having a high relative permeability characteristic on the outer periphery. A coil and a normal mode choke in which one of two power supply wires is wound around two dust cores that fit inside the common mode choke coil, and a wire of the common mode choke coil and a normal mode choke coil A choke coil for a noise filter, characterized in that the wires are connected in series and housed in a case in which pin terminals are attached to the lower surface of the board mounting surface and filled with resin.