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:
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 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:
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 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:
A self-startup circuit for a DC fan includes a voltage sampling device receiving a first control signal, a comparator, and a self-startup 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 self-startup device has a switching device and a diode connected in parallel. The self-startup device has an input terminal connected to the output terminal of the comparator, and outputs a second control signal for keeping the DC fan rotating even when the first control signal has a very low duty cycle.
Abstract:
A method for testing a card reader includes the steps of: identifying a logical drive corresponding to the card reader; determining whether the card reader matches a portable storage device connected to the card reader; displaying error information if the card reader does not match the portable storage device; obtaining a control code of the portable storage device if the card reader matches the portable storage device; testing the performance of the card reader by means of reading and writing data in the portable storage device through the card reader according to the control code.
Abstract:
A card for simulating peripheral component interconnect (PCI) loads is disclosed. The card in accordance with a preferred embodiment of the invention includes an interface configured for electrically connecting to a motherboard; and a load circuit for simulating the different loads, wherein the load circuit comprises at least one power module receiving a voltage from the interface; and the power module dissipates various loads. Because that the card may dissipates 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.