High-efficiency boundary conduction mode tapped-inductor boost LED driver

Abstract

A high-efficiency boundary conduction mode (BCM) tapped-inductor boost converter for constant output current applications is proposed. Besides the well-known advantages from the BCM operation such as the significantly relieved diode reverse-recovery and switching loss, the proposed converter shows a switching frequency which is insensitive to the output voltage variations. This makes the proposed converter very attractive in small form factor mobile LED driver applications. The circuit is analyzed in detail, and a design guideline is presented. Experimental results from an LED backlight driver prototype for a 14" notebook computer are also presented.