Patent ID: 7535733

Claim:
A method of controlling a DC-to-DC converter by operation of a switching control circuit, said DC-to-DC converter comprising a first voltage system circuit comprising a first switching element and a second switching element, a second voltage system circuit comprising a third switching element and a fourth switching element, electric power conversion means for performing electrical power conversion between said first voltage system circuit and said second voltage system circuit, and said switching control circuit, adapted to perform complementary on/off switching of said first switching element and said second switching element, and to perform complementary on/off switching of said third switching element and said fourth switching element, synchronized with said switching of said first and third switching elements, wherein designating a condition in which both of said first and third switching elements are in an ON state and said second and fourth switching elements are in an OFF state as a No. 1 condition, and designating a condition in which both of said first and third switching elements are in the OFF state and said second and fourth switching elements are in the ON state as a No. 2 condition, said method comprises: while said electrical power conversion is being performed from said first voltage system circuit to said second voltage system circuit via said electric power conversion means, cyclically performing a sequence of operations whereby following each occasion when said No. 1 condition is established, said second switching element is switched to the ON state to thereby establish a concurrent ON state in which each of said first switching element, second switching element and third switching element are in the ON state, with said switch-on of said second switching element being performed prior to performing switch-off of each of said first switching element and of said third switching element to establish said No. 2 condition.