The
UCC28911 are
high-voltage flyback 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 flyback 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. Both enable
the very low stand-by power consumption.
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. The frequency jitter helps to reduce EMI filter
cost.