Patent ID: 8611106

Claim:
A system controller for regulating a power conversion system, the system controller comprising: a signal generator configured to receive a feedback signal related to an output signal of a power conversion system, a current sensing signal and an input voltage, and to generate a control signal based on at least information associated with the feedback signal, the current sensing signal and the input voltage, the current sensing signal representing one or more peak magnitudes related to a primary current flowing through a primary winding of the power conversion system; and one or more power-consumption components configured to receive the control signal; wherein: the one or more power-consumption components are further configured to reduce power consumption if the control signal indicates the feedback signal is smaller than a feedback threshold for a first predetermined period of time, the current sensing signal is smaller than a current sensing threshold for a second predetermined period of time, and the input voltage is smaller than a first threshold for a third predetermined period of time in magnitude; and each of the first predetermined period of time, the second predetermined period of time, and the third predetermined period of time is equal to or larger than zero in magnitude.