MP156 is a primary-side regulator that provides accurate constant voltage (CV) regulation without opto-coupler, support buck, buck-boost, or flyback topologies. It has an integrated 500V MOSFET to simplify the structure and reduce costs. These features make it a competitive candidate for off-line low power applications, such as home appliances and standby power. MP156 is a green-mode operation regulator. Both its the peak current and the switching frequency decrease as the load decreases to provide excellent efficiency at light load, thus improving the overall average efficiency. MP156 features various protections, including thermal shutdown (TSD), VCC under-voltage lockout (UVLO), overload protection (OLP), short-circuit protection (SCP), and open loop protection. MP156 is available in the TSOT23-5?and SOIC8 packages.