SLUSBL5A February 2015 – June 2019 UCC28730
The UCC28730 is an isolated-flyback power supply controller which provides accurate voltage and constant current regulation using primary-side winding sensing, eliminating the need for opto-coupler feedback circuits. The controller operates in discontinuous conduction mode with valley switching to minimize switching losses. The modulation scheme is a combination of frequency modulation and primary peak-current modulation to provide high conversion efficiency across the load range. The control law provides a wide dynamic operating range of output power which facilitates the achievement of <5-mW stand-by power.
During low-power operating levels the device has power management features to reduce the device operating current at switching frequencies less than 28 kHz. The UCC28730 includes features in the pulse-width modulator to reduce the EMI peak energy at the fundamental switching frequency and its harmonics. Accurate voltage and current regulation, fast dynamic response, and fault protection are achieved with primary-side control. A complete charger solution can be realized with a straightforward design process, low cost, and low component-count.