High-performance 700V fly-back switcher delivers precise voltage / current control

The UCC28910 and UCC28911 from Texas Instruments are high-voltage fly-back switchers that provide output voltage and current regulation without the use of an optical coupler. Both devices incorporate a 700V power FET and a controller that process operating information from the fly-back auxiliary winding and power FET to provide a precise output voltage and current control. The integrated high-voltage current source for start-up that is switched off during device operation, and the controller current consumption is dynamically adjusted with load. Both enable the very low stand-by power consumption. Control algorithms in the UCC28910 and UCC28911, combining switching frequency and peak primary current modulation, allow operating efficiencies to meet or exceed applicable standards. Discontinuous conduction mode (DCM) with valley switching is used to reduce switching losses. Built-in protection features help to keep secondary and primary component stress levels in check across the operating range. The frequency jitter helps to reduce EMI filter costs, says the company.