Patent ID: 9054584
Filing Date: 2015-06-09
Classification: H02M,Y02B

Abstract:
1. An AC-DC adapter comprising: a switch-mode power supply coupled to receive an input AC voltage, the switch-mode power supply converting the input AC voltage to a DC output voltage that drives a load; a power control loop coupled to the switch-mode power supply, the power control loop receiving the DC output voltage and providing a power control signal to configure the switch mode power supply according to a decay rate of the DC output voltage, wherein the power control loop further comprises: a power mode control circuit that is coupled to the load detector and generates the power control signal, and a load detector that is coupled to the power mode control and counts a number of clock cycles in a time interval during which the DC output voltage decays from a high threshold voltage to an intermediate threshold voltage and compare the number of clock cycles with a predetermined threshold number of clock cycles to determine presence and absence of the load.