MP173 is a primary-side regulator that provides accurate constant voltage (CV) regulation without an opto-coupler. It supports buck, boost, buck-boost, and flyback topologies. It has an integrated 700 V MOSFET to simplify the structure and reduce cost. These features make it an ideal regulator for offline, low-power applications, such as home appliances and standby power. MP173 is a green-mode operation regulator. Both the peak current and switching frequency decrease as the load decreases. This feature provides excellent efficiency at light load and improves the overall average efficiency. MP173 has various protection features including thermal shutdown (TSD), VCC under-voltage lockout (UVLO), overload protection (OLP), short-circuit protection (SCP), and open-loop protection. MP173 is available in a small TSOT23-5 package and SOIC-8 package.