| 摘要 |
PROBLEM TO BE SOLVED: To reduce an iron loss and suppress a power loss, a beat tone, a leakage magnetic flux and a temperature rise in a transformer when a low voltage is selected by switching an output voltage.SOLUTION: In a power supply circuit, a relay switch is provided for switching between a series connection and a parallel connection to each power voltage of the primary-side coils of two identical transformers. When a high voltage is required at a secondary-side output, it is controlled to switch the primary-side winding to the parallel connection by the relay switch, whereas when a low voltage is required at the secondary-side output, it is controlled to switch the two primary-side coils to the series connection by the relay switch. |
