It is also the first device of its type to provide LED driving capabilities in televisions based on the LCD Integrated Power Supply (LIPS) architecture, which combines a television”s main power supply together with the LED driver on one lower cost and higher efficiency printed circuit board.
“The LX27901 continues on our long tradition of innovation in high-performance display lighting solutions, delivering power-efficiency improvements in the 7 to 9 percent range,” said Amir Asvadi, vice president and general manager of the Analog Mixed Signal Group at Microsemi. “This reduction in energy consumption, coupled with the ability to reduce component counts and bill-of-material costs, is driving growth for LIPS-based LCD TVs.”
According to Display Search, more than 200 million LCD TVs ship each year, the majority of which will use LED technology.
“Advanced features such as non-dissipative current balancing of multiple LED strings, the ability to use one transformer design for a wide range of panel sizes and Microsemi”s proprietary ACU_BRITE algorithm for enhancing dimming accuracy have led our largest customer to design the LX27901 into multiple TV models for 2012,” said J.W. Suh, President of South Korean electronics distributor Bescom Global.
Key features include three selectable drive modes, Microsemi”s patented ACU_BRITE(TM) algorithm to provide high-accuracy, high-efficiency dimming over a wide operating range, synchronous regulation to reduce the number of power conversion stages and accurate current matching through Microsemi”s unique non-dissipative balancing technology.
Energy efficiency is crucial in LCD TV applications as efficiency requirements driven by government entities become more stringent, as exemplified by the EnergyStar 5 standard from the US DOE. Traditional solutions utilize an input of 24VDC together with a DC-DC regulator to boost voltage and a current source to control the current/brightness for each LED string. While functional, this multi-stage architecture is highly inefficient.
The LX27901 utilizes Microsemi”s EcoBrite technology and combines the TV power supply and LED driver into a single efficient unit, eliminating the need for a DC-DC boost regulator. EcoBrite also eliminates the need for a dissipative current source due to its patented reactive LED string balancing feature. In addition, the company”s ACU_BRITE dimming technology provides non-dissipative and highly accurate dimming even at very low current levels.