Today's LED lighting challenges are to find efficient dimming devices that fit within existing sockets and which work efficiently in small spaces. Fairchild Semiconductor believes that its FL7701 smart, non-isolated buck LED driver can meet this challenge. It automatically detects the AC input voltage condition to create an internal reference signal that is claimed to result in high power factor correction. The IC also works from a DC input voltage condition, automatically sensing AC versus DC input voltage conditions. The IC can be connected directly to a DC or AC off-line input instead of the traditional technique which uses a transformer which incurs additional losses with the conversion. According to the company, the IC's high functional density and small form factor reduces the bill of material by up to 20% with up to 60% board savings, making it suitable for space-constrained PCBs common in LED lighting applications. It also supports analogue dimming. There are no electrolytic capacitors for the input, output or the VDD supply, which increases reliability and extends lifespan to over five years, instead of three. Digital power factor realisation greater than 0.9 and electrical efficiency of 90% mean energy savings so that the end system meets EnergyStar. The IC is available in an SOP-8 package.n
