DESCRIPTION

· The LT1509 is a comprehensive solution for universal off-line switching power supplies with active power factor correction.
· It integrates PFC and PWM functionalities in a single chip, synchronized up to 300kHz.
· The PWM duty cycle is internally capped at 47% to prevent transformer saturation.
· PWM soft start activates when PFC output reaches the preset voltage.
· In case of a brief line loss, PWM shuts off when PFC output voltage falls below 73% of the preset value.

FEATURES

· Achieves 99% power factor over a 20:1 load current range.
· Features current mode PWM and instantaneous overvoltage protection.
· Includes dedicated overvoltage protection via the OVP pin.
· Minimal line current dead zone and a typical 250 µA start-up supply current.
· Equipped with line switching noise filter and low quiescent current of 13mA.
· Fast 2A peak current gate drivers and separate soft start controls.

APPLICATIONS

· Ideal for universal power factor corrected power supplies and preregulators.
· Suitable for applications requiring synchronized PFC and PWM operations.