ALTAIR04-900 All-Primary-Sensing Switchers STMicroelectronics ALTAIR04-900 All-Primary-Sensing Switchers feature primary side constant voltage operations with no optocoupler. The STMicroelectronics ALTAIR04-900 combines a high-performance low-voltage PWM controller chip and a 900V avalanche-rugged power section in the same package. These STMicroelectronics All-Primary-Sensing Switchers provide quasi-resonant valley switching operation and low standby consumption. ALTAIR04-900 switching regulators are designed for use in AC-DC adapters, SMPS for energy metering, and auxiliary power supplies for 3-phase input industrial systems.