Controller minimizes transformer size in power supplies.
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Press Release Summary:
Pulse Width Modulator Model LT1950 employs control mechanism that protects, simplifies, and reduces size of isolated/non-isolated 15-500 W power supplies with 24 and 48 V input supply rails. Adaptive maximum-duty-cycle clamp circuit prevents transformer saturation and protects MOSFET from failures. Adjustable current-slope compensation allows optimization of transient response. Operating frequency is adjustable from 100-500 kHz. Synchronizable IC is packaged in 16-lead SSOP.
Original Press Release:
PWM Controller Minimizes Transformer Size in Isolated & Non-Isolated Power Supplies
MILPITAS, CA - July 2, 2003 - Linear Technology introduces the LT1950, a Pulse Width Modulator controller with a sophisticated control mechanism to protect, simplify and reduce the size of isolated/non-isolated 15W to 500W power supplies with 24V and 48V input supply rails. The LT1950 features an adaptive maximum duty cycle clamp circuit to prevent transformer saturation and to protect the MOSFET from catastrophic failures. This feature reduces the transformer size by as much as 50%. Moreover, adjustable current slope compensation allows optimization of transient response with a minimum number of output capacitors.
The LT1950's programmable leading edge blanking eliminates the need for current sense filtering. Compared to DC/DC converter modules, the LT1950 solution is smaller, lighter, has lower profile and better airflow and is significantly lower in cost. The main applications are power supplies in telecom, industrial, medical, automotive and aerospace systems where a high reliability isolated/non-isolated power supply rail is used to distribute power within the system.
The LT1950's adaptive maximum duty cycle clamp follows the input voltage so that load and line transients do not cause excessive flux swing in the transformer. Without this feature, designers must use an oversized transformer, larger MOSFETs and extensive filtering. With its adjustable undervoltage lockout (UVLO), the LT1950 can be easily customized to operate with a wide range of input supplies. The operating frequency is adjustable with a resistor from 100kHz to 500kHz. The IC is synchronizable to an external clock while a precision internal reference guarantees an accurate output voltage. The IC is packaged in a 16-lead SSOP.
The LT1950 is guaranteed for operation over junction temperature range from -40°C to 125°C. Pricing for the LT1950 starts at $2.90 each in 1,000-piece quantities.
Summary of Features: LT1950
oProgrammable Adaptive Volt-Second Clamp (Maximum Duty Cycle Clamp)
oProgrammable Leading Edge Blanking
oProgrammable Slope Compensation
oProgrammable UVLO
oCurrent Mode Control
oSmall 16-Lead SSOP
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 frequencydevices. 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.
READER SERVICE: Call toll-free 1-800-4-LINEAR (for literature only), or go to the company's web site: www.linear.com
Note: LT, AND LTC are registered trademarks of Linear Technology Corp.
