| 摘要 |
<p>A dual-mode system for operating electrically powered devices, such as hand-held power tools and appliances, includes a cordless battery pack that supplies the power and current demands of the device in a cordless mode or a corded voltage converter that supplies the necessary power and current demands in a physical envelope commensurate in size and interchangeable with that of the battery pack. The corded voltage converter is provided with a high efficiency power supply that allows the converter to generate the power and current required by the driven device and accommodate widely varying loads consequent to normal operation of the device and do so in a physical envelope that is commensurate in size with and interchangeable with the cordless battery pack. The corded voltage converter includes a power conditioner that conditions input source current, such as 120 or 240 volts AC or DC, to provide a relatively high DC voltage 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 current to a drive motor of the device.</p> |
