A new circuit structure of LLC converter is studied and implemented to achieve wide zero-voltage switching range and wide voltage operation such as consumer power units without power factor correction and long hold up time demand, battery chargers, photovoltaic converters and renewable power electronic converters. The dc converter with the different secondary winding turns is adopted and investigated to achieve the wide input voltage operation (50–400 V). To meet wide voltage operation, the full bridge and half bridge dc/dc converters with different secondary turns can be selected in the presented circuit to have three different voltage gains. According to input voltage range, the variable frequency scheme is employed to have the variable voltage gain to overcome the wide input voltage operation. Therefore, the wide soft switching load variation and wide voltage operation range are achieved in the presented resonant circuit. The prototype circuit is built and tested and the experiments are demonstrated to investigate the circuit performance.