Abstract: A circuit for an electronic device translates logic-low and logic-high voltage levels into other voltage levels suitable for digital intercommunication between the host electronic device and external devices, and between different external devices. The circuit comprises a power supply, a processing module, a communicating module, and a voltage converting module. The power supply provides a first voltage, a second voltage, and a pulse voltage with a predetermined duty cycle. The voltage level converting module converts incoming or outgoing logic voltage levels between a first mode and a second or more modes.

Abstract: A circuit for suppressing audio noise having a common node electrically connected to an output terminal of a preamplifier and an input terminal of a postamplifier is disclosed, in which the preamplifier is provided power by a second voltage supply. The circuit for suppressing audio noise includes a first and a second pulldown switch, a first control switch and a voltage detecting circuit. In which, the first and the second pulldown switch conduct audio noise passing the preamplifier to the ground during the early and the later stage after the second voltage supply is turned on and the voltage is stable, respectively. In addition, the voltage detecting circuit detects whether the voltage is stable or not for deciding whether the circuit for suppressing audio noise must be disabled or not. If the circuit is disabled, the audio signal directly sent to the postamplifier from the preamplifier.

Abstract: A circuit for suppressing audio noise having a common node electrically connected to an output terminal of a preamplifier and an input terminal of a postamplifier is disclosed, in which the preamplifier is provided power by a second voltage supply. The circuit for suppressing audio noise includes a first and a second pulldown switch, a first control switch and a voltage detecting circuit. In which, the first and the second pulldown switch conduct audio noise passing the preamplifier to the ground during the early and the later stage after the second voltage supply is turned on and the voltage is stable, respectively. In addition, the voltage detecting circuit detects whether the voltage is stable or not for deciding whether the circuit for suppressing audio noise must be disabled or not. If the circuit is disabled, the audio signal directly sent to the postamplifier from the preamplifier.

Abstract: The invention provides a loudspeaker mounting mechanism capable of adjusting the loudspeaker angle for generating stereo surrounding sound effect, or meeting personal sound effect favorites. By means of hinge links the loudspeaker to the display in a manner that the loudspeaker can be rotated relatively to the display, instead of being fixed as conventional attached loudspeakers.