Texas Instruments Incorporated (TI) (NYSE:TXN) has the
industry's first single-chip, interleaved power factor correction
(PFC) control circuit for multi-kilowatt communications, server and
industrial systems. The new UCC28070 two-phase, average current-mode
controller allows designers to simplify power design, increase system
reliability and achieve a greater than 0.9 power factor rating, which
improves energy efficiency. Visit http://www.ti.com/UCC28070-pr.
"The increasing need for better energy management is apparent
in every area of our lives, especially at the business operations level.
The magnitude of power requirements for data centers and telecom systems
continues to drive industry-wide efforts to reduce wasted energy and
improve power quality," said Bob Mammano, power management staff
technologist and TI Fellow. "Today's announcement gives power
engineers an innovative solution that raises the bar toward more
efficient power supply control."
Building on more than 20 years of PFC circuit development,
TI's UCC28070 continuous conduction-mode controller provides
unprecedented performance and reduces system cost in applications where
high efficiency and high power factor requirements are important. These
range from high-end communications systems to embedded white goods motor
drives in refrigerators and air conditioners to HID lighting ballasts.
In line-operated systems with power levels from 75 W to 1kW and
above, the UCC28070 helps reduce total harmonic distortion, allowing
today's systems to better maximize usable outlet power and
accommodate extreme variations and disturbances in various AC line
voltage levels used around the world.
Meeting Strict Efficiency Requirements
The UCC28070 helps designers meet the most stringent efficiency
requirements for multi-kilowatt power systems. This PFC controller
allows light-load phase management to enhance a system's
performance -- achieving higher efficiency over the entire load range.
Phase management allows a system to turn on or off phases of the power
supply, so that only the phases required to power the load are enabled.
In a 1.2-kW system, the UCC28070 can initiate an increase of up to
1.5-percent efficiency at a light 20-percent load condition, allowing
designers to exceed energy guidelines set forth by industry initiatives,
such as The Green Grid, Climate Savers Computing Initiative and Project
Big Green. In a 240-watt supply at 20-percent load condition, for
example, this increase in efficiency results in a 27-percent power
savings.
System Reliability and Protection
The device helps increase system reliability by incorporating a
unique 180 degree interleaving method, which reduces the amount of input
and output current ripple and distributes the magnetics to improve
thermal management. Average current mode interleaving allows a system to
achieve between 50 and 100 percent reduction in ripple compared to
today's typical non-interleaved PFC architectures.
The UCC28070's optional programmable-frequency dithering mode
allows a designer to spread the switching frequency over a range to
minimize the generation of electromagnetic interference (EMI). The
dithering feature helps reduce capacitor size, and it gives designers
the ability to use a smaller, less expensive EMI filter. The UCC28070
offers several unique system control and protection features to improve
overall system reliability. An output over-voltage protection scheme
with an open-loop detection feature safeguards the system from common
circuit board failures. Each phase current is accurately balanced with
independent current sensing to prevent excess component heating in the
device's dual-phase operation. In addition, the UCC28070 provides
under-voltage lockout, cycle-by-cycle peak current limit, and a system
over-temperature protection feature.
Two-Phase Single-Chip PFC Controllers for Consumer and High-Power
Applications
In June TI introduced the UCC28060, which is the first single-chip,
transition-mode, two-phase PFC controller for 75- to 800-W applications,
including consumer applications, such as digital TVs, personal computers
and entry-level server platforms. Both the UCC28060 and UCC28070 give
designers the best options as they design power systems that support
power factor correction in end-equipment designs. For more information
on the UCC28060, visit: http://www.ti.com/UCC28060.
Available Today
The UCC28070 is available in a 20-pin TSSOP package. It is sampling
today, with volume production scheduled for January 2008. Suggested
resale pricing in quantities of 100 units is $2.45. An evaluation board,
power factor correction application notes and data sheets are available
at power.ti.com.
About Texas Instruments
Texas Instruments Incorporated provides innovative DSP and analog
technologies to meet our customers' real world signal processing
requirements. In addition to Semiconductor, the company includes the
Education Technology business. TI is headquartered in Dallas, Texas, and
has manufacturing, design or sales operations in more than 25 countries.
For more information, call 214/480-6894 or visit http://www.ti.com
and http://www.power.ti.com.
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