Full-Bridge Controller simplifies DC/DC converters.

Press Release Summary:




Offered in current and voltage modes, LTC3722 zero voltage switching, phase shifted controller is suited for isolated offline and distributed power supplies from 200 W up to several kw. It offers fixed frequency operation with current mode and adaptive zero voltage delay control. Controller also provides closed-loop control method, adaptive/manual delay control, adjustable synchronous rectification timing, adjustable max ZVS delay, and programmable slope compensation.



Original Press Release:



Synchronous PWM Full-Bridge Controller Simplifies 200W-2kW DC/DC Converters



MILPITAS, CA - April 22, 2003 - Linear Technology Corporation announces the LTC3722, a zero voltage switching (ZVS) phase shifted full bridge power supply controller intended for isolated offline and distributed power supplies of 200W up to several kilowatts. It offers fixed frequency operation with current mode control and adaptive zero voltage delay control over all operating conditions, optimizing efficiency and reducing transformer size and EMI. This controller also provides simple programmability for current limit, leading edge blanking, softstart, and short circuit protection, simplifying the circuit and reducing design time. Typical applications include servers, telecommunications, cellular base stations and industrial power supplies.

The LTC3722's adaptive technology is an innovative closed-loop control method for optimizing delay time. By sensing the bridge and input supply directly, the LTC3722 intelligently adapt to any change in load current, temperature, component drift, driver circuitry delay offset, or input voltage variation. The benefits are simpler design, higher efficiency, increased duty cycle capability, lower EMI and consistent performance without circuit tweaking. The LTC3722 allows the user to adjust the delay time to fix the transition delays or even implement specific dynamic timing schemes. Synchronous rectification of MOSFETs and the transformer's secondary power stage are driven 180 degrees output of phase. This reduces voltage ripple and output capacitors as well as improving output capacitor reliability.

The LTC3722 features low startup, operating and quiescent current to ease the burden on external bias circuitry, and the circuit's accurate 5V low dropout regulator provides up to 15mA to power auxiliary circuits. The LTC3722 is offered in two versions current mode (LTC3722-1) and voltage mode (LTC3722-2). Each is housed in a 24-lead SSOP package. They are priced at $5.50 each in 1,0000-piece quantities.

Summary of Features: LTC3722
· Adaptive or Manual Delay control for Zero Voltage Switching
· Adjustable Synchronous Rectification Timing for Highest Efficiency
· Adjustable Maximum ZVS delay
· Integrated Synchronous Rectification Control for Highest Efficiency
· Output Power Levels from 200W to Kilowatts
· Adjustable System Undervoltage Lockout and Hysteresis
· Programmable Slope Compensation

COMPANY BACKGROUND: Linear Technology Corporation was founded in 1981 as a manufacturer of high performance linear integrated circuits. Linear Technology products include operational, instrumentation and audio amplifiers; voltage regulators, power management devices, DC-DC converters and voltage references; comparators; monolithic filters; communications interface circuits; one-chip data acquisition sub-systems; pulse-width modulators and sample-and-hold devices; and high frequency devices. Applications for Linear Technology's high performance circuits include wireless and broadband telecommunications infrastructure, cellular telephones, networking products and satellite systems, notebook and desk top computers, computer peripherals, video/multimedia, industrial and medical instrumentation, automotive electronics, factory automation, process control, military and space systems, and high-end consumer products including digital cameras, MP3 players and other electronic products.

For more information, contact:
Doug Dickinson, Media Relations Manager
Linear Technology Corporation
1630 McCarthy Boulevard
Milpitas, CA 95035-7417
ddickinson@linear.com
408-432-1900

READER SERVICE: Call toll-free 1-800-4-LINEAR (for literature only), or go to the company's web site: www.linear.com

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