Product category:
Power Supply ICs and Controllers
News Release from: Texas Instruments (April 2001-March 2006) | Subject: UCC2891, UCC2892, UCC2893 and UCC2894
Edited by the Electronicstalk Editorial
Team on 16 December 2003
PWM controllers boost convertor
efficiency
Four new PWM controllers significantly simplify implementation of active clamp/reset topologies for high-efficiency switching power supplies.
Four new PWM controllers significantly simplify implementation of active clamp/reset topologies for high-efficiency switching power supplies The peak current-mode controllers increase efficiency in offline power supplies and DC/DC convertors used in high-end desktops, servers, 48V telecommunications and datacommunications, and 42V automotive systems
This article was originally published on Electronicstalk on 8 Nov 2004 at 8.00am (UK)
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Ideal for active-clamp forward or flyback convertors, TI's new UCC2891, UCC2892, UCC2893 and UCC2894 devices include an auxiliary active clamp output driver for efficient single-ended transformer reset.
The controllers reduce switching losses of the convertors by simply programming critical delays to achieve proper active clamp operation and deliver zero-voltage switching (ZVS) to the primary side mosfet switches.
Soft-switching allows the devices to achieve higher efficiencies at high operating frequencies, and increase reliability of the overall system by lowering electromagnetic interference (EMI) and radio-frequency interference (RFI), and reducing power supply component losses.
Building on the success of TI's first generation UCC3580 active-clamp controller, the four new controllers improve performance while eliminating many external components.
The devices include an internal programmable slope compensation circuit, a precise maximum duty cycle limit and a 1MHz synchronisable oscillator with an internal timing capacitor.
For added performance and functionality, the devices feature programmable soft start and shutdown functionality and an accurate line monitoring function that can program a convertor's on and off transitions when determining bulk input voltage levels.
The UCC2891 and UCC2893 also feature a 110V startup feature that removes the need of an external trickle charge boot strap resistor to provide significant cost savings.
TI's UCC289x PWM controllers are available in volume from the company and its authorised distributors.
Available in both 16-pin SOIC and low-profile TSSOP packages, suggested resale pricing for the UCC2892 and UCC2894 is $1.49 in quantities of 1000 units.
Suggested resale pricing for the UCC2891 and UCC2893 with internal 110V startup is $1.57 in quantities of 1000 units.
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