| 摘要 |
<P>PROBLEM TO BE SOLVED: To provide a drive circuit which can perform a highly reliable operation without malfunctioning even if a bootstrap capacitor discharges. <P>SOLUTION: In the drive circuit, when the bootstrap capacitor C1 is discharged and both ends become the same potential, the potential of a connecting point P of main circuit elements Q1, Q2 at a moment that the main circuit element Q2 of a lower arm is turned on is lowered to the vicinity of a ground, and a gate terminal of the main circuit element Q1 of a switching element Q3 becomes 0V, but a second bootstrap capacitor C2 is connected in parallel with the series connection of the switching elements Q3, Q4, and a charging resistor R2 is connected between the switching element Q3 and a power source line. Thus, a voltage between both the ends of the switching element Q3 is not abruptly raised to a control power source 15V, but gradually raised together with the charging of the second bootstrap capacitor C2. <P>COPYRIGHT: (C)2005,JPO&NCIPI |
