The GreenChip II is the second generation of green Switched Mode Power Supply (SMPS) control ICs operating directly from the rectified universal mains. A high level of integration leads to a cost effective power supply with a very low number of external components. The special built-in green functions allow the efficiency to be optimum at all power levels. This holds for quasi-resonant operation at high power levels, as well as fixed frequency operation with valley switching at medium power levels. At low power (standby) levels, the system operates at a reduced frequency and with valley detection.