The UCC28730 isolated-flyback power supply controller provides Constant-Voltage (CV) andConstant-Current (CC) output regulation without the use of an optical coupler, andwake-up signal detection to improve transient response to largeload steps. A minimum switching frequency of 30 Hz facilitates achieving less than 5 mW of no-loadpower. This device processes information from the primary power switch and an auxiliary flybackwinding for precise control of output voltage and current. The wake-up monitoring works with a secondary-side alarm device such as theUCC24650 to deliver rapid response to heavy load steps using minimal output capacitance.
An internal 700-V start-up switch, dynamically- controlled operating states and atailored modulation profile support ultra-low stand-by power without sacrificing start-up time oroutput transient response. Control algorithms in the UCC28730 allow operating efficiencies to meetor exceed applicable standards. Discontinuous conduction mode (DCM) operation with valley-switchingreduces switching losses. Modulation of the switching frequency and primary current peak amplitude(FM and AM) keeps the conversion efficiency high across the entire load and line ranges.