Patent ID: 8072193

Claim:
A phase shift control method for a boost converter, wherein said boost converter comprises a master phase and at least one slave phase paralleled coupled to said master phase; a master-phase inductor current flowing through said master phase has a master-phase charge time interval and a master-phase discharge time interval; a slave-phase inductor current flowing through said slave phase has a slave-phase charge time interval and a slave-phase discharge time interval, and wherein said phase shift control method comprises steps: (a) starting said master-phase charge time interval to increase said master-phase inductor current when said master-phase inductor current is determined to have reached a zero-current judgment value; (b) starting said master-phase discharge time interval when said master-phase charge time interval is completed; finishing said master-phase discharge time interval to complete a current cycle and starting the next said master-phase charge time interval when said master-phase inductor current is determined to have reached said zero-current judgment value; (c) calculating an ideal switching timing whereat said slave-phase inductor current descends to said zero-current judgment value according to a peak value of said slave-phase inductor current in the preceding cycle, and obtaining a physical switching timing in a time point whereat said slave-phase inductor current descends to said zero-current judgment value, and then calculating a conduction timing error between said physical switching timing and said ideal switching timing; and (d) determining the time length of said slave-phase charge time interval in the same cycle according to a function of said conduction timing error and said master-phase charge time interval.