ALTAIR04-900

The ALTAIR04-900 is an offline high voltage all-primary-sensing Switching Regulator operating directly from the rectified mains with minimum external parts. It combines a high-performance low voltage PWM controller chip and a 900V avalanche-rugged power section. The controller is in current-mode specifically designed for offline quasi-resonant fly-back converters. The device provides a constant output voltage using the primary-sensing feedback. This eliminates the need for the optocoupler, the secondary voltage reference, as well as the current sensor, still maintaining an accurate regulation. Besides, the maximum deliverable O/P current can be set so to increase the end-product safety and reliability during fault events. Quasi-resonant operation is guaranteed by a transformer demagnetization sensing I/P which turns on the power section. The same i/p also serves the o/p voltage monitoring, to perform CV regulation and to achieve mains-independent maximum deliverable output current.