Abstract: An exemplary PCB defines a circular first via and includes a first signal layer, a second signal layer, a first reference layer between the first and second signal layer, and a signal transmission line having a first portion on the first signal layer and a second portion on the second signal layer. The first signal layer has a circular first weld pad coaxial with the first via and electrically connected to the first portion, the second layer has a circular second weld pad coaxial with the first via and electrically connected to the second portion. The first weld pad is electrically connected to the second weld pad through the first via, the reference layer defines a first through hole coaxial with the first via, the radius of the first via is R1, the radius of the first through hole is R2, R2=R1+d1, 1.5 mil?d1?4 mil.

Abstract: A charging circuit employed in an electronic apparatus is operable to charge a portable electronic device. The charging circuit includes a charging control microchip including two control terminals, a southbridge microchip, a logic control circuit, and a basic input/output system (BIOS). The southbridge microchip and the BIOS are both electronically connected to the logic control circuit to control the logic control circuit to set or reset voltage of the two control terminals, then the charging control microchip is switched to a charging mode or a data transmission mode according to the voltage of the two control terminals.

Abstract: An electronic apparatus includes a microphone, a processor, a motherboard, and a voice recognition microchip. The voice recognition microchip compares a voice command with a pre-stored voice command. If the voice command is identical with the pre-stored voice command, the processor outputs a control signal to the motherboard. The motherboard controls the electronic apparatus to perform an action corresponding to the control signal.

Abstract: An indicator light control circuit includes a basic input output system (BIOS) integrated circuit (IC), a microcontroller, a signal control unit, an electronic switch, and an indicator light. The microcontroller includes a general purpose input output (GPIO) pin. When different operating options of the indicator light are set into and by the BIOS IC, the BIOS IC controls the GPIO pin of the microcontroller to output command signals, such as a low voltage signal, a high voltage signal and pulse signals, then the signal control unit generates and outputs signals according to the command signals. Thus, the electronic switch is operated to turn on or turn off or to pulse when controlling the operation of the indicator light(s).

Abstract: An all in one (AIO) computer implemented as a personal computer (PC) or a display includes a high definition multimedia interface, a speaker, and a speaker control circuit. The speaker control circuit includes an earphone interface circuit, a main controller, a signal processing unit, and a signal control circuit. The earphone interface circuit detects whether an earphone is inserted into the AIO computer. When the earphone interface circuit detects the earphone is connected to the AIO computer, if the AIO computer is implemented as the PC, the main controller sends a first muting signal. If the AIO computer is implemented as the display, the main controller sends a second muting signal, and the signal control circuit controls and mutes the speaker according to the first muting signal and the second muting signal.

Abstract: A driving module for driving a Digital Visual Interface includes an integrated chip, a pull-up resistor unit, and a voltage converter. The pull-up resistor unit includes a plurality of resistors. The voltage converter includes an array of resistors comprising a plurality of resistors and a MOSFET. Each resistor of the array of resistors includes a first end and a second end. The first ends are electrically connected to outputs of the integrated chip, and the second ends are electrically connected to a drain of the MOSFET. A source of the MOSFET is connected to ground, and a gate of the MOSFET is electrically connected to an output of the main board.

Abstract: A printed circuit board electrically connected to a display includes a plurality of display control units, a plurality of first forward different signal lines, at least one second forward differential signal line, and a plurality of zero-ohm resistors. The display control units provide differential signals for the display through the differential signal lines and the zero-ohm resistors. Any two of the first forward differential signal lines are electrically connected together at one end to form a first node. One end of the second forward differential signal line is electrically connected to the first node. The other end is electrically connected to another first forward differential signal line to form a second node. The zero-ohm resistors are placed on the first forward differential signal lines and the second forward differential signal lines and are electrically connected between the display control units and the display.

Abstract: An all-in-one audio system includes an audio chip, an audio interface, first and second audio signal amplifiers, a speaker, a woofer, a multi-function controller, a high definition multimedia interface (HDMI), and a switch. The multi-function controller is connected to the audio chip, the switch, the audio interface, the first and second audio signal amplifiers, and the HDMI. When the multi-function controller detects a high definition multimedia signal through the HDMI, the multi-function controller turns off the switch, decodes the high definition multimedia signal into an audio signal, and transmits the audio signal to the audio interface, and the first and second audio signal amplifiers. The first and second audio signal amplifiers amplify the audio signal and output the amplified audio signal to the speaker and woofer.

Abstract: A timing control circuit used to provide a timing control signal to a FSB power supply of a computer includes a first resistor, a second resistor, and a switch. The first resistor and the second resistor are connected in series between a power supply and ground. One end of the switch is connected to the computer and receives a state signal from the computer. Another end of the switch is connected a node between the first and second resistors and outputs a timing control signal according to the state signal.

Abstract: An exemplary power supply system and method for a motherboard includes a power circuit providing power for a south bridge, and a controller having first and second transistors. An input terminal of the power circuit is connected to a power supply. An output terminal of the power circuit is connected to a reset pin of the south bridge. A first terminal of the first transistor is configured for receiving a control signal from the south bridge. A second terminal of the first transistor is connected to a first terminal of the second transistor. A second terminal of the second transistor is connected to the reset pin of the south bridge. Each of the first and second transistors has a third terminal grounded.

Abstract: An exemplary power supply control circuit includes a first electric switch, a second electric switch, a third electric switch, a power supply, and an output terminal. The first electric switch has a first terminal connected to an SIO chip to receive a control signal. When the control signal is at a high level, the first electric switch is turned on, the second electric switch is turned off, the third electric switch is turned off, and the output terminal outputs no power supply. When the control signal is at a low level, the first electric switch is turned off, the second electric switch is turned on, the third electric switch is turned on, and the output terminal outputs the power supply.

Abstract: An exemplary voltage regulating circuit for a motherboard includes a selecting switch and a first switch module, the selecting switch comprising a first input terminal arranged to receive a standby power provided by a power supply, a first control terminal arranged to receive a state signal from the motherboard via a first switch module controlled by a power good signal generated by the power supply, and an output terminal, wherein, when the motherboard is turned off, the state signal is at a high level and the first switch module is turned on by the power good signal for turning off the selecting switch to stop outputting the standby power.

Abstract: A card for simulating peripheral component interconnect (PCI) loads includes an interface configured for electrically connecting to a motherboard and a load circuit configured for simulating the different loads. The load circuit comprises at least one power module receiving a voltage from the interface. The power module is capable of changing resistance of the power module thereby to thermally consume various powers to simulate the different loads. Because the card consumes various power according to testing requirement, the stability of the motherboard can be tested in various load power without connecting actual PCI loads to the motherboard.

Abstract: An exemplary method for controlling rotation speed of a computer fan includes: judging the type of a fan by comparing two rotation speeds detected before and after changing a duty cycle of a PWM signal respectively; controlling the computer fan as a 4-pin fan the PWM signals if the rotation speeds are different; and controlling the computer fan as a 3-pin fan via voltage signals converted from the PWM signals if the rotation speeds are equal. And an exemplary circuit for controlling rotation speed of a computer fan is capable of controlling rotation speed of the 4-pin fan via PWM signals, and controlling rotation peed of the 3-pin fan via voltage signals converted from PWM signals.

Abstract: A power supply circuit for a motherboard includes a first resistor, a second resistor, a Schottky diode, and a direct current (DC) voltage source. The Schottky diode includes a first anode, a second anode, and a cathode. The first anode of the Schottky diode is respectively coupled to terminals of the first and second resistors, another terminal of each of the first and second resistors is respectively coupled to a power supply and ground. The second anode of the Schottky diode is coupled to the DC voltage source, the cathode of the Schottky diode is coupled to a south bridge.

Abstract: A circuit for controlling rotation speed of a computer fan includes a fan connector providing for controlling the rotation speed of the computer fan, a rotation speed detector providing for detecting the rotation speed of the computer fan, a BIOS chip connected to the fan connector via the rotation speed detector and provided for receiving, and comparing rotation speed signals from the rotation speed detector, a super I/O chip connected to the BIOS chip and provided for outputting either a PWM signal or another PWM signal to be converted to a voltage signal to control rotation speed of the computer fan according to the result of the comparison, a integrated circuit connected to the super I/O chip and the fan connector and configured for converting the another PWM signal to an analog voltage signal.

Abstract: A network overclock control circuit for a computer includes an RC circuit, first and second comparator circuits, and first and second switch circuits. A signal pin of a network indicating lamp is connected to input terminals of the first and second comparator circuits via the RC circuit. Output terminals of the first and second comparator circuits are respectively connected to first and second clock pins of a clock chip via the first and second switch circuits. When network has little traffic, the first and second comparator circuits control the first and second switch circuits to output low level signals. When network has medium to high traffic, the first and second comparator circuits control the first and second switch circuits to output high and low level signals. When network is overloaded, the first and second comparator circuits control the first and second switch circuits to output high level signals.

Abstract: A sleep/awake circuit includes an infrared receiving/sending module, a micro-control circuit, and a bus control circuit. The micro-control circuit sends a command signal to the infrared receiving/sending module at predetermined intervals. The infrared receiving/sending module detects the presence or absence of a user and then sends a signal back to the micro-control circuit indicating a result. According to the result, the micro-control circuit exchanges data and clock signals with the bus control circuit. The bus control circuit then sends control signals to the computer to control sleep/awake states of the computer.

Abstract: A power supply circuit for a pulse width modulation controller includes a first resistor and an electric switch having first, second, and third terminals. The first terminal is capable of receiving a control signal of a computer. The second terminal is connected to a stand-by power supply of the computer. The third terminal is connected to the pulse width modulation controller via the first resistor.

Abstract: An exemplary power supply control circuit includes a first electric switch, a second electric switch, a third electric switch, a power supply, and an output terminal. The first electric switch has a first terminal connected to an SIO chip to receive a control signal. When the control signal is at a high level, the first electric switch is turned on, the second electric switch is turned off, the third electric switch is turned off, and the output terminal outputs no power supply. When the control signal is at a low level, the first electric switch is turned off, the second electric switch is turned on, the third electric switch is turned on, and the output terminal outputs the power supply.