| 摘要 |
A DC-DC converter has improved electrical characteristics, including a voltage-reduction detection circuit and a zero-voltage switching control circuit. In the voltage-reduction detection circuit, in a period when a switching device is OFF, when a drain voltage of the switching device is reduced to an input voltage level, a voltage of a connection section of registers is allowed to reach a threshold voltage level to reverse a signal outputted from a NOR gate from a higher level to a lower level. In the zero-voltage switching control circuit, the signal reduced as above is received and a signal outputted from a NOR gate is reversed to a higher level, according to which a pulse-control signal outputted from a NOR gate to the switching device is reversed to a higher level to turn on the switching device. Since the output pulse-control signal from the NOR gate controls switching operations performed by the switching device, no switching loss occurs and zero-voltage switching can be performed; accordingly, short-circuit loss also does not occur.
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