A DC to DC converter with intermediate conversion into AC power, including: a transformer having a primary winding and a secondary winding; a first DC to AC conversion circuit having its AC terminals coupled with the primary winding of the transformer; a first AC to DC conversion circuit having its AC terminals coupled across a first tap and a second tap of the secondary winding of the transformer; a second AC to DC conversion circuit having its AC terminals coupled across a third tap and a fourth tap of the secondary winding of the transformer, wherein the first tap and the second tap are arranged between the third tap and the fourth tap along the secondary winding of the transformer; and at least one first power switch, being arranged between one of DC terminals of the first AC to DC conversion circuit and one of DC terminals of the second AC to DC conversion circuit. By having the solution as above, the DC output voltage may be changed between two levels by operating only one power switch. Because a power switch is more expensive than a multiple of power diodes, by reducing the number of power switches responsible for changing the level of DC output voltage, it is helpful for decreasing the cost and complexity of control. Besides, the power loss can be decreased due to switching of less power switch.