| 摘要 |
PROBLEM TO BE SOLVED: To lower a switching loss when voltage rises, by providing a switching element controlling power supply to the primary side of a transformer and a gate pulse control means supplying a pulse to a gate of the switching element in synchronization with oscillation voltage of the secondary side of the transformer. SOLUTION: If a gate pulse generating circuit is constituted so that it generates a pulse only when a zero-cross signal arrives, an additional tuning circuit is not necessary, because the gate pulse generating circuit itself has a synchronization function. Thus, the current flowing in a switching element 13 becomes a sine wave after the gate pulse is impressed, by adding the gate pulse in synchronization with the rise of oscillation voltage. Consequently, the current at the voltage rise of the switching element 13 is zero, then, a switching element loss, that is, a power loss in the switching element is lowered. |
