Abstract:
A method and apparatus for controlling a fan is disclosed. In one embodiment, a method for controlling a fan includes applying power to the fan at startup. The fan may be supplied a predetermined amount of current, which may break the inertia of the fan propeller and begin its rotation. As the propeller begins rotating, the speed at which it rotates may be monitored. The fan startup routine may continue until the fan reaches or exceeds a minimum fan speed threshold. Once the fan has at least reached the minimum speed, the amount of current supplied to the fan may be reduced such that the fan rotates at minimum speed, and an automatic fan control algorithm may begin executing. By reducing the current such that the fan operates at a minimum speed, the amount of audible noise generated by the fan during startup may be kept to a minimum level.
Abstract:
In one embodiment, a system comprises a programming unit coupled to at least one programmable fuse and configured to program the programmable fuse. In addition, the system comprises a monitoring circuit coupled to the programmable fuse and configured to monitor electrical characteristics associated with the programmable fuse while the programmable fuse is being programmed. In one embodiment, the monitoring circuit is configured to detect a voltage associated with the programmable fuse. Furthermore, the monitoring circuit is configured to compare the detected voltage associated with the programmable fuse with a predetermined voltage value (i.e., endpoint detection). If the detected voltage is equal to or less than the predetermined voltage value, the monitoring circuit is configured to change a state of a control signal to stop the programming of the programmable fuse. Otherwise, the programming unit continues to program the programmable fuse.
Abstract:
A single-wire bus protocol named Budget Sensor Bus (BBUS) for simplified system management. The BBUS may transmit information packets in NRZ format from a monitored device/circuit to a host. In one embodiment, each packet comprises a start sequence, a data type, a device or register number, device data, and a stop sequence. The BBUS may directly transmit raw data bits from the monitored device/circuit to the host and may use the start sequence to communicate to the host the bit frequency that is used by the monitored device/circuit. Following the start sequence the host may get in sync with the monitored device/circuit and may be enabled to directly read the data bits that follow. The BBUS may provide a means for the monitored device/circuit to immediately transfer device information to the host. All functions and operations required to interpret the device information may reside within the host. The BBUS may transmit information packets from the monitored device/circuit to the host, but not from the host to the monitored device/circuit. In one embodiment the BBUS is used for thermal management, where the monitored device/circuit comprises temperature/voltage sensors, the host is an SIO controller, and temperature/voltage data is transmitted from the sensors to the SIO controller.
Abstract:
An amplifier circuit. In one embodiment, the amplifier circuit includes an output stage and a gain stage. The gain stage includes first and second differential output terminals that may be coupled to first and second differential input terminals of the output stage. The gain stage includes a first feedback loop and a second feedback loop. First and second half-stages within the gain stage may be coupled to provide the second feedback loop. The first half-stage may be coupled to control a first output current at the first output terminal of the gain stage, while the second-half-stage may be coupled to control a second output current at the second output terminal of the gain stage.
Abstract:
In one set of embodiments the invention comprises a highly accurate, low-power, compact size DAC utilizing charge redistribution techniques. Two complementary conversions may be performed and added together to form a final DAC output voltage by performing charge redistribution a first time, and again a second time in a complementary fashion, followed by a summing of the two charge distributions, in effect canceling the odd order capacitor mismatch errors. By canceling all odd order mismatch errors the accuracy of the DAC may become a function of the square of the mismatch of the two capacitors, resulting in greatly increased accuracy. When performing the complementary conversions for multiple bits, the sequence in which each of the two capacitors is charged may be determined to minimize the even-order errors, especially second-order errors. The DEM technique may be applied, in conjunction with the complementary conversions, with less oversampling than required by current DEM implementations, resulting in even-order errors being substantially reduced in addition to all odd-order errors being eliminated.
Abstract:
A method and apparatus for configuration control and power management through special signaling is provided. In one embodiment, a computer system may include a processor and a plurality of devices that may act as a source device, a destination device, or both. A particular source device may be configured for communications with a destination device. The source device may further be configured to violate one or more known communications rules when communicating the with the destination device. The destination device may be configured to detect the violation. The violation of a known communications rule by the source device may indicate a pending change of state in the computer system, or that a change of state has occurred.
Abstract:
A method and apparatus for providing power management functions in a computer or other electronic system which includes a primary power supply, a trickle power supply and a battery back-up power supply. A power management circuit includes a storage element which stores an indication of the current turn-on or turn-off condition of the primary power supply. The power management circuit also includes a group of logic gates which process signals which are supplied to the storage element under normal operating conditions to control the turn-on or turn-off condition of the primary power supply. The power management circuit senses when the trickle supply is deactivated due to a line power failure or the like, and subsequently switches the power supply inputs of the storage element and certain of the logic gates from the trickle supply to the battery back-up supply. A blocking signal is generated which prevents those signals which require the trickle supply for logic integrity from being applied to the storage element. In this manner, only signals which do not require the trickle supply for logic integrity are applied to the storage element while the trickle supply is deactivated.
Abstract:
An arrangement for interconnecting groups of users into collision domains in a Local Area Network such as an Ethernet comprises a plurality of repeater groups, with each repeater group being connected to a group of user stations. The arrangement also comprises an electronically reconfigurable switch matrix. The switch matrix comprises a plurality of segment lines (or other transmission media) each of which is used to form one collision domain or Ethernet segment. Switch elements under the control of a microcontroller selectively connect particular repeater groups (and the associated user groups) to particular segment lines to form Ethernet segments, each Ethernet segment being a single collision domain. Internetworking devices such as bridges and routers may also be connected to the switch matrix to interconnect particular collision domains.
Abstract:
In a fast Ethernet, each station is connected to the hub by four unshielded twisted pairs. A first pair is transmit only for the station and receive only for the hub, a second pair is transmit only for the hub and receive only for the station, and the third and fourth pairs are bidirectional. Both the station and the hub use their transmit only and the bidirectional pairs for data transmission and their receive only pair for collision detection.
Abstract:
A VSLI transceiver chip incorporating an improved analog PLL circuit for recovering a digital clock signal from a digital data signal having pulse widths which may vary during each data cycle. The analog PLL clock recovery circuit comprises a phase detector, a gain control circuit, a variable current charge pump, a loop filter and a variable frequency oscillator. The phase detection means for detecting, during each data cycle, the phase error between the digital data signal and recovered digital clock signal, and produces first end second digital control pulse signals in response to the detection of the phase error. The gain control means produces third and fourth digital control pulse signals during each data cycle. The value of the third and fourth control pulse signals during each data cycle depends on the value of the digital data signal, the value of the recovered clock signal, and the value of the second digital control pulse signal during the data cycle, and the change in value of the third and fourth control pulse signals is responsive to the change in the value of the recovered digital clock signal. The variable current charge pump receives the first and second digital control pulse signals. The recovered digital clock signal is produced by variable frequency oscillator, having a clock frequency proportional to the produced analog control signal.