Analysis and Design Considerations of LLCC Resonant Multioutput DC/DC LED Driver With Charge Balancing and Exchanging of Secondary Series Resonant Capacitors

Abstract

A new rectifier for multioutput LED driver is proposed based on a charge exchanging and balancing principle in the secondary resonant capacitors. Combined with common ground rectifier and LLCC resonant topology, a four-output dc-dc LED driver is proposed with minimum quantity of secondary charge balancing capacitors. In the LLCC topology, the secondary side resonant capacitors can be used as dc blocking and charge balancing capacitors. The proposed LED driver can automatically share the average output currents by the charge balancing and exchanging among secondary resonant capacitors. The operating principle and the brief design guidelines for the four-output LLCC resonant dc-dc converter are presented. The guaranteed current sharing capability of the proposed four-output LED driver is also analyzed thoroughly. Finally, a 150 W four outputs LLCC resonant dc-dc LED driver is built-up to verify the theoretical analysis.