| 摘要 |
<p>A corded/cordless dual-mode power-operated device, such as a household vacuum cleaner, can be operated in corded mode from a conventional power source and in a cordless mode using energy provided from an internal rechargable battery and which includes an internal battery charger for recharging the battery when the device is in its corded mode. The internal charger includes a voltage converter that converts input source current to a relatively high DC current that is chopped at a comparatively high frequency, e.g., 25 KHz, by switching devices. The high-frequency, high voltage current is presented to a step-down transformer with the stepped-down output rectified to provide a low-voltage DC suitable for recharging the internal battery when the device is in its corded mode. The voltage converter advantageously provides for the high efficiency conversion of the input energy to meet the charging current demands of the internal battery in a physically compact device.</p> |
