| 摘要 |
<P>PROBLEM TO BE SOLVED: To provide a motor drive circuit that can make a synchronous rectifying current flow without narrowing a variable range of a duty ratio of a drive current. <P>SOLUTION: Drive signals modulated by PWM signals are imparted to switches Q1, Q2 and Q5 of an upper arm of an inverter circuit 1 when a distributor 3 generates on-signals. There is arranged a synchronous rectifying signal generation circuit 7 for generating synchronous rectifying signals Vi that are generated at timing delayed from timing when the PWM signals are changed to second levels from first levels after the start of a PWM cycle, and extinguished at timing before timing when the PWM signals are changed to the first levels from the second levels after the end of the PWM cycle. The distributor 3 generates on-signals to the switches of the upper arm, and during the generation of off-signals to switches Q2, Q4 and Q6 of a lower arm, the distributor makes the synchronous rectifying signal generation circuit perform synchronous rectification by imparting signals modulated by the synchronous rectifying signals Vi to the switches of the lower arm as the drive signals. <P>COPYRIGHT: (C)2005,JPO&NCIPI |
