Abstract: Disclosed is a circuit for regulating a power supply. In one embodiment, the circuit includes a signal generator for generating a square wave signal that varies in magnitude between a first voltage and a second voltage, and a voltage regulation circuit. A duty cycle of the square wave generated by the signal generator varies according to a signal provided to the signal generator. The voltage regulation circuit, coupled to the signal generator, outputs a DC voltage in response to the circuit receiving the square wave signal. The magnitude of the DC voltage varies between the first voltage and a third voltage, wherein the third voltage is greater than the second voltage, and wherein the magnitude of the DC voltage varies directly with the duty cycle of the square wave signal.

Abstract: A method and system determines the status of an external power supply connection to an information handling system. A subsystem manager of the information handling system compares an external power source identification signal and a power available signal to determine whether external power is available, unavailable or faulty. For instance, an information handling system configured as a portable computer receives external power from an AC/DC converter along with an identification signal for the converter. A state machine running on the portable computer system's Super I/O compares the identification signal and a power available signal from an internal charger to determine state of the external power source and indicate the state to a user.

Abstract: Disclosed is a circuit for regulating a power supply. In one embodiment, the circuit includes a signal generator for generating a square wave signal that varies in magnitude between a first voltage and a second voltage, and a voltage regulation circuit. A duty cycle of the square wave generated by the signal generator varies according to a signal provided to the signal generator. The voltage regulation circuit, coupled to the signal generator, outputs a DC voltage in response to the circuit receiving the square wave signal. The magnitude of the DC voltage varies between the first voltage and a third voltage, wherein the third voltage is greater than the second voltage, and wherein the magnitude of the DC voltage varies directly with the duty cycle of the square wave signal.

Abstract: The speed of a fan motor is controlled by varying a DC voltage to the fan motor. A series pass transistor is used to vary the DC voltage to the fan motor. A power management controller sets the fan motor speed by outputting pulses to a pulse-to-DC voltage converter that changes the pulses to a proportional DC control voltage for controlling the series pass transistor. A tachometer output amplifier circuit is used to remove DC components and amplify to useful logic levels a low level tachometer output signal from the fan motor. The amplified tachometer signal is used by the power management controller in controlling the rotational speed of the fan motor.

Abstract: An information handling system is provided which includes a wired network controller fixedly mounted in the system and an optional wireless network card which is pluggably receivable by a connector in the system. The system includes a first indicator for annunciating network activity and a second indicator for annunciating that the link is good as well as its link rate. Status processing logic is situated between the wireless card connector, the network controller and the first and second indicators to permit the wireless card and the network controller to share the first and second indicators.

Abstract: A method and system determines the status of an external power supply connection to an information handling system. A subsystem manager of the information handling system compares an external power source identification signal and a power available signal to determine whether external power is available, unavailable or faulty. For instance, an information handling system configured as a portable computer receives external power from an AC/DC converter along with an identification signal for the converter. A state machine running on the portable computer system's Super I/O compares the identification signal and a power available signal from an internal charger to determine state of the external power source and indicate the state to a user.

Abstract: A method which includes selecting a boot device priority sequence, and configuring—in response to the boot device priority sequence—an I/O controller such that a MASTER or SLAVE designation of at least one IDE device conforms to the boot device priority sequence. A computer system which includes at least one printed circuit board operably connecting at least one processor, at least one memory, at least one I/O controller, and at least one IDE controller; at least one IDE bus operably connecting at least two IDE device connectors with the at least one IDE controller; and at least one cable select signal pin of each of the at least two IDE device connectors operably coupled to the at least one I/O controller.