Abstract: A circuit adopted in a computer includes a power supply (20) with an output (PS_+5VSB) for providing a standby voltage, a motherboard (10) with a pin (MB_+5VSB) for receiving the standby voltage, a switch circuit (30) connected between the output of the power supply and the pin of the motherboard. The switch circuit has a control terminal fed with a S5# signal which is at high level to turn on the switch circuit, and at low level to turn off the switch circuit when the computer is in a S5 power state to cut off the standby voltage supply from the power supply to the motherboard for reducing power consumption of the motherboard; the control terminal of the switch circuit further being supplied with an inverted PWRBTN# signal for turning on the switch circuit when the PWRBTN# signal is at low level for switching on or off the computer.

Abstract: A circuit for preventing a computer from being powered on before a CPU of the computer has been properly installed, the circuit includes a power supply (70) for the computer, a controller (60) connected to the power supply configured for controlling the power supply, a switch (10) exposed outside the computer for convenient operation, and a switching device (Q1). The controller includes a terminal for receiving a computer startup signal. The switch is connected to the terminal of the controller for sending the computer startup signal to the controller when the switch is triggered, wherein when the computer startup signal is sent to the sensing terminal of the controller, the controller controls the power supply to provide power to the computer. The switching device includes a control terminal configured for sensing if the CPU is installed to control conduction of the switching device.

Abstract: A circuit is used for preventing a computer from being powered up before a CPU voltage of the computer is prepared properly. The circuit includes a power supply for providing power to the computer, a power button for powering on the computer system, a power controller, and a switch. The power controller includes an input terminal connected to the power button and an output terminal for electrical connection to the power supply. The input terminal receives a PWRBT# signal when the power button is momentarily triggered, and the output terminal outputs a PSON# signal to the power supply to control the power supply to provide the electrical power to the computer in response to the received PWRBT# signal. The switch is serially connected between the output terminal and the power supply. The switch includes a control terminal monitoring if the CPU voltage is prepared properly so as to control conduction of the switch and further to control connection between the output terminal and the power supply.

Abstract: A circuit for protecting a motherboard includes a first transistor (Q1), a second transistor (Q2), a third transistor (Q3), and a power control circuit (200). The power control circuit includes a power controller (10), and a power supply (20), and a fourth transistor (Q4) connected therebetween. The first transistor is supplied with a CPU power signal on the motherboard. The second and third transistors are jointly supplied with a sleep signal and turned on if the CPU power signal is at low level after the power supply is turned on, thereby turning off the fourth transistor and grounding a PWRBTN# pin of the power controller to turn off the power supply for protecting the motherboard from damage due to no CPU power-on voltage applied thereto after the power supply is turned on.

Abstract: A delay circuit (12) includes a resistor (R1), a capacitor (C), and a discharging circuit (14). The discharging circuit includes a PNP transistor (Q1) and an NPN transistor (Q2). The capacitor has one terminal connected to one terminal of the resistor, and the other terminal connected to ground. The PNP transistor has a base connected to the other terminal of the resistor, a collector, and an emitter connected to a voltage source. The NPN transistor has a base connected to the collector of the PNP transistor, an emitter connected to ground, and a collector connected to the one terminal of the resistor.

Abstract: An assembly includes a circuit board (20) with a component attached thereon, a power supply (10) for providing power to the circuit board and the component separately, an ACPI chipset (65) for controlling the power supply, a protecting circuit (61) connected to the component, an I/O controller (64), and an enable circuit (62) for activating the I/O controller. The protecting circuit generates a protecting signal while the component is not connected properly to its power source. The I/O controller is responsive to the protecting signal to send a control signal to the ACPI chipset for shutting off the power supply.

Abstract: A delay circuit (12) includes a resistor (R1), a capacitor (C), and a discharging circuit (14). The discharging circuit includes a PNP transistor (Q1) and an NPN transistor (Q2). The capacitor has one terminal connected to one terminal of the resistor, and the other terminal connected to ground. The PNP transistor has a base connected to the other terminal of the resistor, a collector, and an emitter connected to a voltage source. The NPN transistor has a base connected to the collector of the PNP transistor, an emitter connected to ground, and a collector connected to the one terminal of the resistor.

Abstract: A circuit adopted in a computer includes a power supply (20) with an output (PS_+5VSB) for providing a standby voltage, a motherboard (10) with a pin (MB_+5VSB) for receiving the standby voltage, a switch circuit (30) connected between the output of the power supply and the pin of the motherboard. The switch circuit has a control terminal fed with a S5# signal which is at high level to turn on the switch circuit, and at low level to turn off the switch circuit when the computer is in a S5 power state to cut off the standby voltage supply from the power supply to the motherboard for reducing power consumption of the motherboard; the control terminal of the switch circuit further being supplied with an inverted PWRBTN# signal for turning on the switch circuit when the PWRBTN# signal is at low level for switching on or off the computer.

Abstract: A time delay circuit includes an RC circuit with a resistor and a capacitor connected, and a switch. The switch includes a first terminal, a second terminal, and a control terminal for controlling conduction of the first and second terminals. The first terminal is connected to an end of the resistor, which is connected to the capacitor. The second terminal is connected to ground, and the control terminal is connected to the other end of the resistor configured for receiving an input signal. When the input signal changes from logical low to logical high to turn off the switch, the capacitor is charged to a predetermined value with a predetermined rise time beginning from the change of the input signal. When the input signal changes from logical high to logical low to turn on the switch, the first and second terminals of the switch conduct to quickly discharge the capacitor to the predetermined value substantially synchronized with the change of the input signal.

Abstract: A circuit is used for preventing a computer from being powered up before a CPU voltage of the computer is prepared properly. The circuit includes a power supply for providing power to the computer, a power button for powering on the computer system, a power controller, and a switch. The power controller includes an input terminal connected to the power button and an output terminal for electrical connection to the power supply. The input terminal receives a PWRBT# signal when the power button is momentarily triggered, and the output terminal outputs a PSON# signal to the power supply to control the power supply to provide the electrical power to the computer in response to the received PWRBT# signal. The switch is serially connected between the output terminal and the power supply. The switch includes a control terminal monitoring if the CPU voltage is prepared properly so as to control conduction of the switch and further to control connection between the output terminal and the power supply.

Abstract: A circuit for preventing a computer from being powered on before a CPU of the computer has been properly installed, the circuit includes a power supply (70) for the computer, a controller (60) connected to the power supply configured for controlling the power supply, a switch (10) exposed outside the computer for convenient operation, and a switching device (Q1). The controller includes a terminal for receiving a computer startup signal. The switch is connected to the terminal of the controller for sending the computer startup signal to the controller when the switch is triggered, wherein when the computer startup signal is sent to the sensing terminal of the controller, the controller controls the power supply to provide power to the computer. The switching device includes a control terminal configured for sensing if the CPU is installed to control conduction of the switching device.

Abstract: A circuit for protecting a motherboard includes a first transistor (Q1), a second transistor (Q2), a third transistor (Q3), and a power control circuit (200). The power control circuit includes a power controller (10), and a power supply (20), and a fourth transistor (Q4) connected therebetween. The first transistor is supplied with a CPU power signal on the motherboard. The second and third transistors are jointly supplied with a sleep signal and turned on if the CPU power signal is at low level after the power supply is turned on, thereby turning off the fourth transistor and grounding a PWRBTN# pin of the power controller to turn off the power supply for protecting the motherboard from damage due to no CPU power-on voltage applied thereto after the power supply is turned on.

Abstract: An assembly includes a circuit board (20) with a component attached thereon, a power supply (10) for providing power to the circuit board and the component separately, an ACPI chipset (65) for controlling the power supply, a protecting circuit (61) connected to the component, an I/O controller (64), and an enable circuit (62) for activating the I/O controller. The protecting circuit generates a protecting signal while the component is not connected properly to its power source. The I/O controller is responsive to the protecting signal to send a control signal to the ACPI chipset for shutting off the power supply.