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US 2017/0256356 A1Published application
Power supply circuit
AssigneeMurata Manufacturing Co., Ltd.
InventorHiroyuki TAKATSUJI
Life of this patent
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Abstract
A power supply circuit includes a DC-DC converter and a choke coil. The choke coil includes a pair of coils wound in mutually opposite directions, and the coils are connected between a DC power source and the DC-DC converter. In the choke coil, a self-resonating frequency in a common mode is higher than a self-resonating frequency in a normal mode. In the choke coil, a normal mode impedance at the highest frequency in an AM band is higher than a common mode impedance at the lowest frequency in an FM band.
Claims4
A power supply circuit comprising:
- a DC-DC converter, including a switching element that switches a DC input voltage inputted from a DC power source, that supplies a DC output voltage according to an on-off duty ratio of the switching element to a load;
- and
- a choke coil, including a pair of coils wound in mutually opposite directions, in which the paired coils are connected between the DC power source and the DC-DC converter,
- wherein in the choke coil, a self-resonating frequency in a common mode, in which a current flows in the paired coils in the same direction, is higher than a self-resonating frequency in a normal mode, in which the current flows in the paired coils in mutually opposite directions;
- and
- in the choke coil, a normal mode impedance at the highest frequency in a predetermined low-frequency band is higher than a common mode impedance at the lowest frequency in a high-frequency band that is higher than the low-frequency band.
3 more elements
Dependencies are inferred from the claim text.