Improving efficiency of a pre-/post-switching regulator (PFC/PWM) at light loads using green-mode function

The efficiency of a pre-/post-switching regulator degrades as the power delivered to the load lessens. To improve the efficiency of a pre-/post-switching regulator at light loads, a green-mode function is proposed in this paper. By using a green-mode function, efficiency can be improved at lower power consumption by 8 to 25 percentage points depending on the power level being delivered to the load. Experimental results are provided to confirm the improvement in the efficiency.