The MP171 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. MP171 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. MP171 has various protection features including thermal shutdown (TSD), VCC undervoltage lockout (UVLO), overload protection (OLP), short-circuit protection (SCP), and openloop protection. MP171 is available in a small TSOT23-5 package and SOIC-8 package.Primary­Side CV Control, Supporting Buck, Boost, BuckBoost, and Flyback Topologies Integrated 700 V MOSFET and Current Source < 30 mW No­Load Power Consumption Up to 2 W Output Power Maximum DCM Output Current Less than 40 mA Maximum CCM Output Current Less than 60 mA Low VCC Operating Current Frequency Foldback Limited Maximum Frequency Peak Current Compression Internally Biased VCC TSD, UVLO, OLP, SCP, Open­Loop Protection