The UCC28911D is a Fly-back Switcher with constant-voltage constant-current and primary-side control. It is high-voltage fly-back switcher that provides output voltage and current regulation without the use of an optical coupler. The device incorporates 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 startup that is switched off during device operation and the controller current consumption is dynamically adjusted with load. Control algorithms in the 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.
Constant-voltage and constant-current output regulation without optical-coupler
Valley switching and frequency dithering to ease EMI compliance
Thermal shut down
Low line and output overvoltage protection
±5% Output voltage regulation accuracy
±5% Output current regulation with AC line and primary inductance tolerance compensation
700V Start-up and smart power management enables <30mW standby power
115kHz Switching frequency design for high-power density
