| 摘要 |
<p><P>PROBLEM TO BE SOLVED: To solve the following problem encountered when the voltage VC of a capacitor C is converted to a desired value relative to input voltage Vin by repeatedly turning on and off switching elements Sp1, Sn2 to increase or decrease the absolute value of current passed through a coil L, power loss occurs in conjunction with the operation of turning on the switching element Sp1. <P>SOLUTION: The absolute value of the current of the coil L is gradually reduced by turning off the switching elements Sp1, Sn2 (Fig.9(a)). Switching elements Sn1, Sp2 are kept on for a predetermined time after the current of the coil L is zeroed and the coil L is thereby filled with energy (Fig.9(b+)). Thereafter, the switching elements Sn1, Sp2 are turned off (Fig.9(b)). Thus, the electric charges of the parasitic capacitors pc of the switching elements Sp1, Sn2 can be discharged without fail so as to switch them at zero volt. <P>COPYRIGHT: (C)2009,JPO&INPIT</p> |
