. This paper proposes a simple design technique for LLC converter operating under wide input voltage and load range variation. LLC resonant tank design has two degrees of freedom, namely LLC tank quality factor (Q) and inductance ratio (K). It aims to maximize efficiency throughout the required range of operating conditions by choosing a design which minimizes Q and current form factor of primary resonant current. The proposed design is compared with two other existing design approaches and tested on an experimental prototype of 300W LLC converter for input voltage range 20-40V, typical of micro-inverter applications. The proposed design shows rated efficiency improvement of 3% over existing methods.