DESCRIPTION

· The LT1249 is an 8-pin power factor controller designed for universal offline power systems, requiring minimal external components.
· It employs fixed high-frequency PWM current averaging, eliminating the need for slope compensation, resulting in reduced line current distortion and smaller magnetic components.
· The device features a multiplier with a square gain function from the voltage amplifier to maintain low line current distortion and high system stability at light loads.
· It includes filtering to reject line switching noise, minimizing instability when fed into the multiplier.
· The LT1249 offers comprehensive protection features such as peak current limiting and overvoltage protection, with an internally set switching frequency of 100kHz.

FEATURES

· High power factor across a wide load range with line current averaging.
· Capable of international operation without the need for switches.
· Instantaneous overvoltage protection ensures safety and reliability.
· Minimal line current dead zone due to low bias voltage at the current input.
· Start-up supply current typically at 250 mA.
· Effective rejection of line switching noise.
· Synchronization capability for coordinated operation.
· Low quiescent current of 9mA enhances energy efficiency.
· Fast 1.5A peak current gate driver for robust performance.

APPLICATIONS

· Universal power factor corrected power supplies.
· Preregulators for systems up to 1500W.