| 摘要 |
PURPOSE:To provide the stable noise reduction characteristic due to the change of element parameters and to simplify the design by selecting the main inductance so as to keep resonance frequency low as compared with the switching frequency. CONSTITUTION:With the fluctuation of a source impedance CS, the value of a main inductance L2 is decided based on a formula I so as to keep resonance frequency f1 lower than switching frequency fSW The resonance frequency f1 of the formula I is a resonance point frequency between the main inductance L2 and a source impedance CS. Therefore, the minimum value CS<min> at the fluctuation of the source impedance CS is used for the design. As a result, even though the source impedance CS is fluctuated, the noise reduction characteristic in the frequency band higher than the switching frequency fSW can be minimized. |
