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ON Semiconductor is flying the green flag this week at APEC, with product and reference-design announcements that all have an energy-savings focus. Indeed, the company is continuing its GreenPoint reference-design program. Laurent Jenck, Director of System Engineering for Power Supplies at ON, states, "GreenPoint assumes meeting the toughest worldwide regulations in standby power, active power, and power factor correction." Meanwhile the NCP1901 Power Factor Correction (PFC) controller for notebook adapters delivers 90W to 120W
The NVP1901 targets full-size notebooks with larger 15-in to 17-in screens. The IC integrates both a PFC controller and a PWM controller for the DC-DC stage. The design implements a half-bridge resonant topology that delivers active-mode efficiency of 89.4%. Jenck also points out that ON specifies their ICs and reference designs in a realistic-usage scenario. For instance, the NCP1901 efficiency and power specifications are measured at the end of the 6-ft DC-power cable used to connect a power supply to a notebook PC. Jenck warns that some companies rely on specs at the output of the converter. The ON design meets Energy Star 2.0 requirements at the end of the cable.
ON claims that an adapter using the NCP1901 will be slightly longer and a bit thicker than a typical writing pen. The width will be about that of a BlackBerry-type smart phone. The IC will sell for $1.95 (2500).
The ON reference design demonstrations includes a 32-in TV with what ON calls an LCD Integrated Power Supply (LIPS). Relative to TVs in the past, Energy Star focused its attention on standby power but last year turned its attention to active power. TV vendors, however, have struggled to meet active-power guidelines specified in Energy Star 3.0 (see related link below).
According to ON's Jenck, the power supply architecture is one culprit. The typical LCD TV includes a power supply architecture with three stages -- a PFC stage that generates around 400V DC, a DC-DC stage that converts 400V DC to 12V DC, and a 12V DV to 2000V AC stage to drive the CCFL (Cold Cathode Fluorescent Lamp) backlights. Indeed the CCFL supply is often separate from the main power supply.
The ON design eliminates a conversion stage, converting directly from 400V DC to 2000V AC for the CCFL lights. Jenck claims that the backlights account for as much as two thirds of the power used by an LCD TV. The LIPS design reduces overall power consumption by 25% and costs by 20% to 25%. The design delivers 180W for TVs ranging in size from 23 in to 42 in, and meets Energy Star 3.0 guidelines.
The lighting reference design makes the LED case as a replacement for Halogen desk lamps. ON retrofitted a Halogen lamp bought in a retail store with a Cree MC-E LED module and an 8W power supply. The result eliminates the 2.4-lb transformer required by the Halogen lamp, improves light intensity and requires around 25% of the power. All of the reference design documentation is available at www.onsemi.com/powewrsupplies.
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