Abstract: An voltage detection device includes a comparator circuit comprising a first input terminal connected to a system power supply, a second input terminal connected to a standby power supply, an output terminal capable of outputting a control voltage according to comparison result; an indicator circuit; and a switch circuit connected between the standby power supply and the indicator circuit, comprising a control terminal to receive the control voltage from the comparator circuit thereby to control the standby power supply supplied to the indicator circuit or not; a power state terminal of the computer connected to a node between the standby power supply and the indicator circuit, wherein the power state terminal is at a low level when the computer is turned off. The voltage detection device can ensure that all the power supplies provide power to the computer components normally.

Abstract: A polyphase source detecting circuit configured for detecting a polyphase source having at least two phase sources includes at least two sampling circuit and an alarm circuit. Each sampling circuit has a control switch. A control terminal of the control switch of each sampling circuit is connected to one of the phase sources of the polyphase source respectively. The alarm circuit has a first transistor, a first LED, and a second LED. The anodes of the first and second LEDs are connected to a power supply. The cathode of the first LED is connected to the gate of the first transistor and connected to ground via the control switches of the sampling circuits in turn. The cathode of the second LED is connected to the drain of the first transistor. The source of the first transistor grounded.

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: A memory detecting circuit includes five switch elements and two indication devices. A first switch element is connected to a standby power, and also connected to memory sockets of a first channel to receive a first memory detecting signal. A second switch element is connected to the first switch element and the standby power. A third switch element is connected to the second switch element and the standby power, and also connected to memory sockets of a second channel to receive a second memory detecting signal. A fourth switch element is connected to the third switch element and the standby power. A fifth switch element is connected to the fourth switch element and the standby power. When there are memories installed into the memory sockets of the first channel and the second channel, the second indication device indicates that the memories run in a dual channel mode.

Abstract: A power-on circuit of a computer includes a heat sink, an SIO chip, a connector, a first electric switch, a second electric switch, and a third electric switch. When the heat sink is installed properly, the heat sink is grounded, and the first electric switch is turned off. After a power-on button is pressed down, a power supply on pin of the SIO chip sends a low level signal to turn off the second electric switch, the third electric switch is turned on, a power supply on pin of the connector is at a low level, and the computer is powered on. When the heat sink is installed improperly, the heat sink is not grounded, the first electric switch is turned on, the third electric switch is turned off, the power supply on pin of the connector is at a high level, and the computer cannot be powered on.

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 memory detecting circuit includes five switch elements and two indication devices. A first switch element is connected to a standby power, and also connected to memory sockets of a first channel to receive a first memory detecting signal. A second switch element is connected to the first switch element and the standby power. A third switch element is connected to the second switch element and the standby power, and also connected to memory sockets of a second channel to receive a second memory detecting signal. A fourth switch element is connected to the third switch element and the standby power. A fifth switch element is connected to the fourth switch element and the standby power. When there are memories installed into the memory sockets of the first channel and the second channel, the second indication device indicates that the memories run in a dual channel mode.

Abstract: An voltage detection device includes a comparator circuit comprising a first input terminal connected to a system power supply, a second input terminal connected to a standby power supply, an output terminal capable of outputting a control voltage according to comparison result; an indicator circuit; and a switch circuit connected between the standby power supply and the indicator circuit, comprising a control terminal to receive the control voltage from the comparator circuit thereby to control the standby power supply supplied to the indicator circuit or not; a power state terminal of the computer connected to a node between the standby power supply and the indicator circuit, wherein the power state terminal is at a low level when the computer is turned off. The voltage detection device can ensure that all the power supplies provide power to the computer components normally.

Abstract: An overvoltage protection system includes a voltage divider, a compare circuit, and a switch discharge circuit. A voltage regulator module is connected to the switch discharge circuit via the voltage divider. The compare circuit is connected to the switch discharge circuit. When the voltage regulator module outputs an overvoltage, the compare circuit turns on the switch discharge circuit to discharge remaining power in motherboard components and turn off the computer. The overvoltage protection circuit gives a rapid response to overvoltage output from the voltage regulator module, thereby protecting the motherboard components from being damaged.

Abstract: A power-on circuit of a computer includes a heat sink, an SIO chip, a connector, a first electric switch, a second electric switch, and a third electric switch. When the heat sink is installed properly, the heat sink is grounded, and the first electric switch is turned off. After a power-on button is pressed down, a power supply on pin of the SIO chip sends a low level signal to turn off the second electric switch, the third electric switch is turned on, a power supply on pin of the connector is at a low level, and the computer is powered on. When the heat sink is installed improperly, the heat sink is not grounded, the first electric switch is turned on, the third electric switch is turned off, the power supply on pin of the connector is at a high level, and the computer cannot be powered on.

Abstract: A start-up circuit which decreases a start-up current and stabilizes running of a DC fan. The start-up circuit includes a digital-analog converter for convert a digital control signal from a control chip to an analog control signal, a voltage sampling device connected to an output terminal of the digital-analog converter, a comparator, a switching device for controlling start-up of the DC fan, and a feedback device adjusting current passing through the switching device. The comparator includes two input terminals and an output terminal. One input terminal is connected to an output terminal of the voltage sampling device. The switching device is connected to the output terminal of the comparator. An output signal of the switching device is inputted to the other input terminal of the comparator via the feedback device.

Abstract: A polyphase source detecting circuit configured for detecting a polyphase source having at least two phase sources includes at least two sampling circuit and an alarm circuit. Each sampling circuit has a control switch. A control terminal of the control switch of each sampling circuit is connected to one of the phase sources of the polyphase source respectively. The alarm circuit has a first transistor, a first LED, and a second LED. The anodes of the first and second LEDs are connected to a power supply. The cathode of the first LED is connected to the gate of the first transistor and connected to ground via the control switches of the sampling circuits in turn. The cathode of the second LED is connected to the drain of the first transistor. The source of the first transistor grounded.

Abstract: An apparatus for automatic testing of a PS/2 interface includes a micro controller unit, a PS/2 port, and a plurality of LEDs. The micro controller unit is coupled with both a data pin and a clock pin of the PS/2 interface. The LEDs coupled to the micro controller unit simulate functions of a keyboard. A related method for testing the PS/2 interface is also provided.

Abstract: In one preferred embodiment, a power indicator circuit for a computer comprises a light-emitting diode (LED) indicating power management states of a computer; a first resister connected between one pole of the LED and a power source; a second resistor connected between the other pole of the LED and a power source, a first branch circuit connected between the one pole and ground; and a second branch circuit connected between the other pole and ground. Wherein the first resistor and the second resistor control a current through the LED. Because the LED emits lights of different colors or turns off according to the different power management states, it is easy for users to see what the power management state of the computer is.

Abstract: The present invention provides a computer-based method for selecting MOSFETs suitable for a circuit design. The method includes the steps of: providing a database (18) that stores specifications and product information of various MOSFETs; receiving specifications of a circuit design; analyzing the circuit design specifications and determining whether the circuit design specifications satisfy the predetermined requirements for a normal circuit design; computing specifications of proper MOSFETs for the circuit design according to the specifications, and determining if the circuit design specifications satisfy the predetermined requirements; and searching the database for the proper MOSFETs according to the specifications of the proper MOSFETs. A related system is also provided.

Abstract: A pulse width modulation (PWM) generating circuit includes a first comparator, a first resistor, a second resistor, a third resistor, a fourth resistor, a capacitor, and a diode. The first resistor and the second resistor are connected in series between a voltage input and ground. The third resistor, the fourth resistor, and the capacitor are connected in series between the voltage input and ground. The first comparator has a non-inverting input connected to a node between the first resistor and the second resistor, an inverting input connected to a node between the fourth resistor and the capacitor, and an output connected to a node between the third resistor and the fourth resistor. The diode is connected between the non-inverting input and the output. The inverting input of the first comparator provides triangular wave signals to a second comparator by which PWM signals are generated.

Abstract: A control circuit for command signals of a clock generator includes a power supply end, an output end, a control end, a diode, a first resistor and a second resistor. The first resistor, the diode, and the second resistor are connected in series between the power supply end and the ground. The diode has an anode connected to the first resistor and a cathode connected to the second resistor. The control end is connected to a node between the diode and the second resistor; the output end is connected to a node between the diode and the first resistor. The output end outputs the command signals to the clock generator.

Abstract: An LCD backlight driving circuit is provided for providing protection to LCD backlight lamps. In a preferred embodiment, the driving circuit for LCD backlight lamps comprises: a PWM controller sending control signals; two transistors receiving the control signals and sending two low-voltage pulse signals; an inverter converting the two low-voltage pulse signals to a high-voltage AC (Alternating Current) power; two lamps; two overvoltage protection circuits connected to the two lamps respectively; a voltage feedback module connected to the two lamps, a current feedback module connected to one of the two lamps; and a double-bridge circuit connected between the two lamps, and connected to the current feedback module for controlling the PWM controller to turn-on or turn-off. The driving circuit is capable of providing defective connection protection and open-circuit protection to LCD backlight lamps, and proportionately adjusting current flowing through the lamps.

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 method for writing data onto a boot-up compact disc includes the steps of: encoding an optional bootstrap program providing a plurality of boot-up functions; controlling a CD writer (13) to write the optional bootstrap program, drivers of a computer device and basic input output system (BIOS) codes (122) of the computer device onto the boot-up compact disc (15). A related system is also disclosed.