Texas Instruments UCC28730 PSR flyback controller

Texas Instruments’ UCC28730 isolated-flyback power supply controller provides constant-voltage and constant-current output regulation without the use of an optical coupler, plus signal detection to improve transient response to large load steps. A minimum switching frequency of 30 Hz facilitates achieving less than 5 mW of no-load power.

The device processes information from the primary power switch and auxiliary flyback winding for precise control of output voltage and current. The monitoring works with a secondary side alarm device to deliver rapid response to heavy load steps using minimal output capacitance.

An internal 700 V start-up switch, dynamically controlled operating states and a tailored modulation profile support low standby power without sacrificing startup time or output transient response. Control algorithms are said to allow operating efficiencies to meet or exceed applicable standards. Discontinuous conduction mode operation with valley-switching reduces 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.