| 摘要 |
PROBLEM TO BE SOLVED: To reduce ringing noise without increasing the number of components in a printed circuit board with a switching power source packaged therein. SOLUTION: A loop 1 wherein the ringing noise of the switching power source is transmitted, is determined, a print pattern p10 with which parasitic inductance and parasitic capacitance can be enlarged, is determined within the loop 1 and its line inductance is controlled. A frequency of the ringing noise at that time is determined from a natural frequency of the loop 1. only by control to enlarge the line inductance of the print pattern p10 without increasing the number of components, the frequency of the ringing noise can be reduced, so that the printed circuit board wherein high-frequency ringing is suppressed, and the inexpensive switching power source can be configured. COPYRIGHT: (C)2004,JPO&NCIPI
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