| 摘要 |
PURPOSE: A portable power supply is provided to achieve improved conveniences by supplying power to the product using a USB cable even upon absence of personal computer or a battery cell. CONSTITUTION: A portable power supply(301) comprises a power input unit(311) coupled to an external device for supplying DC power voltage; a constant voltage unit(341) for outputting a constant voltage by dropping the DC power voltage output through the power input unit, into a predetermined DC voltage; a power output unit(351) coupled to a USB cable, and which transmits the DC voltage to a voltage terminal of the USB cable; a noise removing unit(331) interposed between the power input unit and the constant voltage unit, and which removes the noise from the DC power voltage; and a switching unit(321) interposed between the power input unit and the constant voltage unit. When the switching unit is turned on, DC power voltage supplied from the external device is transmitted to the constant voltage unit. When the switching unit is turned off, DC power voltage supplied from the external device is not transmitted to the constant voltage unit.
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