LT8311

FEATURES LT8311 Synchronous Rectifier Controller with Opto-Coupler Driver for Forward Converters DESCRIPTION n Wide Input Supply Range: 3.7V to 30V n Preactive Mode: n No Pulse Transformer Required n DCM Operation at Light Load n SYNC Mode: n FCM or DCM Operation at Light Load n Achieves Highest Efficiency n 1.5% Feedback Voltage Reference n 10mA Opto-Coupler Driver n Output Power Good Indicator n Integrated Soft-Start Function APPLICATIONS n Offline and HV Car Battery Isolated Power Supplies n 48V Isolated Power Supplies n Industrial, Automotive and Military Systems L, LT, LTC, LTM, Linear Technology and the Linear logo are registered trademarks of Linear Technology Corporation. All other trademarks are the property of their respective owners. The LT®8311 is used on the secondary side of a forward converter to provide synchronous MOSFET control and output voltage feedback through an opto-coupler. The LT8311’s unique preactive mode allows control of the secondary-side MOSFETs without requiring a traditional pulse transformer for primary- to secondary-side communication. In preactive mode, the output inductor current operates in discontinuous conduction mode (DCM) at light load. If forced continuous mode (FCM) operation is desired at light load, the LT8311 can, alternatively, be used in SYNC mode, where a pulse transformer is required to send synchronous control signals from the primary-side IC to the LT8311. The LT8311 offers a full featured opto-coupl...