| 摘要 |
<P>PROBLEM TO BE SOLVED: To easily realize soft switching in which switching loss is reduced with a simple circuit configuration, without preparing any additional circuit in a step-up chopper circuit. <P>SOLUTION: In a step-up chopper circuit, a reactor 11 and a blocking diode 12 are connected in series between an input and output, a single switching element 13 is connected in parallel between the input and output, and an input voltage V<SB POS="POST">IN</SB>is stepped up with a predetermined step-up ratio through on/off operation of the switching element 13 to generate an output voltage V<SB POS="POST">OUT</SB>of a fixed value. In a method of controlling the step-up chopper circuit, a duration of ON-time T<SB POS="POST">ON</SB>of the switching element 13 is calculated by the expression T<SB POS="POST">ON</SB>=I<SB POS="POST">LA</SB>×2L/V<SB POS="POST">IN</SB>, a switching cycle T of the switching element 13 is calculated by the expression T=T<SB POS="POST">ON</SB>×V<SB POS="POST">OUT</SB>/(V<SB POS="POST">OUT</SB>-V<SB POS="POST">IN</SB>) on the basis of the duration of ON-time T<SB POS="POST">ON</SB>, a voltage between both ends of the switching element 13 is detected just before the switching element 13 is turned on, and the switching element 13 is turned on in a discontinuous mode where the voltage between both ends is approximated to an input voltage, thereby controlling the switching element 13 by zero current switching. <P>COPYRIGHT: (C)2013,JPO&INPIT |
