Common mode choke coil with edgewise windings and line filter including same
A common mode choke coil comprises: a Mn—Zn ferrite core which is shaped square, forms a closed magnetic path, and which has an initial permeability of at least 3,000 at 100 kHz and at least 100 at 10 MHz, respectively, at room temperature; and first and second edgewise windings which are formed respectively of first and second rectangular insulated wires. The first edgewise winding is provided around a core leg of the Mn—Zn ferrite core, and the second edgewise winding is provided around a core leg of the Mn—Zn ferrite core located oppositely to the core leg having the first edgewise winding provided therearound. This structure enables the core characteristics to be fully utilized without an influence of stray capacity of winding.
1. A common mode choke coil comprising:
a Mn—Zn ferrite core which is shaped square, forms a closed magnetic path, and which has an initial permeability of at least 3,000 at 100 kHz and at least 100 at 10 MHz at room temperature; and
a first and second edgewise winding which is formed of a first rectangular insulated wire, and which is provided around a core leg of said Mn—Zn ferrite core; and
second edgewise winding which is formed of second rectangular insulated wire, and which is provided around a core leg of said Mn—Zn ferrite core located oppositely to said core leg having said first edgewise winding provided therearound, said second edgewise winding being wired independent of said first edgewise winding.
2. A common mode choke coil as claimed in claim 1 , wherein said Mn—Zn ferrite core has a main component composition comprising 44.0 to 49.8 mol % Fe 2 O 3 , 15.0 to 26.5 mol % ZnO, 0.1 to 3.0 mol % CoO, 0.02 to 1.00 mol % Mn 2 O 3 and the remainder consisting of MnO, and also has a subsidiary component composition comprising at least one of 0.010 to 0.200 mass % V 2 O 5 , 0.005 to 0.100 mass % Bi 2 O 3 , 0.005 to 0.100 mass % In 2 O 3 , 0.005 to 0.100 mass % PbO, 0.001 to 0.100 mass % MoO 3 and 0.001 to 0.100 mass % WO 3 .
3. A common mode choke coil as claimed in claim 1 , wherein said Mn—Zn ferrite core has a main component composition comprising 44.0 to 49.8 mol % Fe 2 O 3 , 15.0 to 26.5 mol % ZnO, 0.02 to 1.00 mol % Mn 2 O 3 and the remainder consisting of MnO, and also has a subsidiary component composition comprising at least one of 0.010 to 0.200 mass % V 2 O 5 , 0.005 to 0.100 mass % Bi 2 O 3 , 0.005 to 0.100 mass % In 2 O 3 , 0.005 to 0.100 mass % PbO, 0.001 to 0.100 mass % MoO 3 and 0.001 to 0.100 mass% WO 3 .
4. A line filter comprising:
a Mn—Zn ferrite core which is shaped square, forms a closed magnetic path, and which has an initial permeability of at least 3,000 at 100 kHz and at least 100 at 10 MHz at room temperature; and
a first edgewise winding which is formed respectively of a first rectangular insulated wire, and which is provided around a core leg of said Mn—Zn ferrite core; and
second edgewise winding which is formed of second rectangular insulated wire, and which is provided around a core leg of said Mn—Zn ferrite core located oppositely to said core leg having said first edgewise winding provided therearound, said second edgewise winding being wired independent of said first edgewise winding, wherein
one terminations of said first and second edgewise windings are input terminals, the other terminations of said first and second edgewise windings are output terminals, and said first and second windings are connected to each other such that respective magnetic fluxes generated by said first and second edgewise windings cancel out each other when a line current is applied to said input terminals.
5. A common mode choke coil as claimed in claim 1 , used in a line filter having no by-path capacitors.
6. A common mode choke coil as claimed in claim 2 , used in a line filter having no by-path capacitors.
7. A common mode choke coil as claimed in claim 3 , used in a line filter having no by-path capacitors.
8. A line filter as claimed in claim 4 , wherein said line filter has no by-path capacitors.
9. A line filter as claimed in claim 4 , wherein said line filter has one common mode choke coil.