LT1509CN#PBF

LT1509 is a power factor and PWM controller. It is a complete solution off-line switching power supplies utilizing active power factor correction. The PFC section is identical to the device PFC controller except the EN/SYNC pin is removed because PFC and PWM are synchronized internally. The current mode PWM section (this device is the voltage-mode counterpart) contains all the primary side functions to convert the PFC preregulated high voltage output an isolated low voltage output. The PWM duty cycle is internally limited to 47% (maximum 50%) to prevent transformer saturation. PWM soft start begins when PFC output reaches the preset voltage. In the event of brief line loss, the PWM will be shut off when the PFC output voltage drops below 73% of the preset value. It is used in application such as universal power factor corrected power supplies and preregulators etc.