| 摘要 |
PURPOSE: A switch control circuit is provided to reduce costs by driving the switch without using an additional rectifier, while preventing an electrical shock. CONSTITUTION: A switch control circuit comprises a sensing and timer unit(10) for sensing the operation of the switch button of a door phone or a video phone, and maintaining the state in accordance with the result of sensing; an oscillation control and oscillation unit(20) for receiving an output from the sensing and timer unit and generating an oscillation signal; a power supply and boost unit(30) for receiving the output signal from the sensing and timer unit and oscillation signal from the oscillation control and oscillation unit, generating a power, amplifying a power and outputting the amplified power; and a charging unit(50) charged with the voltage output from the power supply and boost unit, and which uses the charged voltage as a drive voltage for a switch.
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