Sun Microsystems, Inc.

Other

Jonathan E Starr

Alexander Dougald Taylor

Michael A Ang

Sai V Vishwanthaiah

Drew George Doblar

Trung T Nguyen

Leo Yuan

Chaim Nmi Amir

Derek Shuntao Tsai

A stringed instrument including an arm extending besides the strings from the body to the headstock such that said arm supports the tensions of the tuned strings, thereby eliminating the need for a neck to support this tension, and allowing for the use of fingerboards of a wide range of shapes which greatly improves ergonomic properties of the instrument.

String instruments

A driver capable of launching signals into a transmission line and of terminating signals at a receiver end of the transmission line includes within the driver a circuit for controlling the output impedance and a circuit for controlling the output slew rate. Accordingly, a desired output impedance can be advantageously established and maintained over a wide range of variations in operating conditions, manufacturing processes and output voltage levels. Such a driver also advantageously limits any crowbar current, thereby reducing the overall power consumption of the driver with little, if any, degradation of driver performance. The driver includes a pull up circuit coupled to receive at least one of a plurality of control codes. The pull up circuit includes pull up output circuit and an impedance control buffer circuit, a parallel pull up circuit, the parallel pull up circuit and the pull up output circuit being controllable to adjust the impedance of the pull up circuit. The driver also includes a pull down circuit coupled to receive at least one of the plurality of control codes. The pull down circuit includes at least one pull down output circuit and a parallel pull down circuit, the parallel pull down circuit being controllable to adjust the impedance of the pull down circuit. The output impedance of the driver is further controlled during transitional phases of turning on and turning off the pull down circuit and the pull up circuit under a plurality of process, voltage and temperature (PVT) conditions.

Dynamic termination logic driver with improved impedance control

A Scheme-1 Termination scheme maximizes system signaling rates by minimizing the signal settling-time when the distance from the middle node to the intersection of the transmission lines is much smaller than the sum of the distances from the end nodes to the intersection of the transmission lines. If the distance from the middle node to the intersection of the transmission lines is not much smaller than the sum of the distances from the end nodes to the intersection of the transmission lines, it has been discovered that a Scheme-2 Termination scheme minimizes the signal settling-time. Alternately, when a Scheme-3 Termination scheme is available, the Scheme-3 Termination scheme maximizes system signaling rates by minimizing the signal settling time when the third transmission line length is more than the second transmission line length divided by two. Otherwise a Scheme-1 Termination scheme minimizes the signal settling time. Additionally, for a given termination scheme, the settling time can be changed by adjusting the lengths of the transmission lines. The impact of such adjustments on settling time can be predicted and maximized by following certain formulas.

Method for determining optimal configuration for multinode bus

A receiver is provided which quickly and efficiently recognizes signals by including with the receiver a resolving circuit which is coupled to a signal generation circuit which provides a differential current. The resolving circuit is coupled to a latching circuit. The resolving circuit can operate with supply voltage levels as low as one threshold voltage. Also, the signal setup and hold times are inherently vary small due to the high intrinsic bandwidth of the receiver. Other advantages include reduced power consumption, high speed operation, good rejection of input noise and power supply noise, ability to resolve small (e.g., 1.0 mVolt) voltage differences, reduced capacitive loading, and the ability to function with a variety of types of drivers, including HSTL, DTL and PECL.

Method for differentiating a differential voltage signal using current based differentiation

A method may be provided which controls the output impedance of a driver which includes within the driver an impedance circuit and a slew rate control. Accordingly, a desired output slew rate and a desired output impedance can be advantageously established and maintained over a wide range of variations in operating conditions, manufacturing processes and output voltage levels. Such a method also advantageously limits any crowbar current, thereby reducing the overall power consumption of the driver with little, if any, degradation of driver performance.

Method for an output driver with improved impedance control

A driver may be provided which controls output impedance of a driver which includes within the driver an impedance circuit and slew rate control. Accordingly, a desired output slew rate and a desired output impedance can be advantageously established and maintained over a wide range of variations in operating conditions, manufacturing processes and output voltage levels. Such a driver also advantageously limits any crowbar current, thereby reducing the overall power consumption of the driver with little, if any, degradation of driver performance.

Output driver with improved impedance control

An information handling system includes a plurality of transmission lines coupled together at one end and having a characteristic impedance, a driver circuit coupled to one of the transmission lines, a plurality of receiver circuits individually coupled to distinct ones of the transmission lines for resolving the signals, and on-chip terminators having a output impedance corresponding to the characteristic impedance and that can be coupled or decoupled from a node by on-chip circuitry. In this embodiment, the terminators are separate and distinct from driver circuitry. However, when a node is in a receive configuration, its corresponding termination resistor is tied to the transmission line at that node, and its corresponding driver circuit presents a high impedance output to the node. A second embodiment provides driver circuits having particular on-chip pull-up and pull-down resistances, one of the either the pull-up or pull-down resistances being used to terminate the bus for those nodes which are in a receive configuration. In this second embodiment, separate terminators are not required, due to the driver operating as the terminator.

Apparatus for dynamic termination logic signaling

An information handling system includes a plurality of transmission lines coupled together at one end through resistance elements having a particular resistance, a driver circuit coupled to one of the transmission lines, a plurality of receiver circuits individually coupled to distinct ones of the transmission lines for resolving the signals, and on-chip termination resistors having a resistance corresponding to the characteristic impedance and that can be coupled or decoupled from the output node by on-chip circuitry. In this embodiment, the termination resistors are separate and distinct from driver circuitry. However, when the node is in a receive configuration, its corresponding termination resistor is tied to the transmission line at that node, and its corresponding driver circuit presents a high impedance output to that node. A second embodiment provides driver circuits having particular on-chip pull-up and pull-down resistances, one of the either the pull-up or pull-down resistances being used to terminate the bus for those nodes which are in a receive configuration. In this second embodiment, separate terminating resistances are not required, due to the driver operating as the terminator.

Apparatus for reducing reflections when using dynamic termination logic signaling

A method of controlling impedance of a driver capable of launching signals at a driving end of a transmission line and capable of terminating signals at the receiver end of the transmission line controls the impedance of the driver across process, voltage, and temperature (PVT) variations by selectively enabling and disabling at least one of a plurality of output elements according to an impedance control code. The impedance control code compensates for variations in output impedance due to PVT variations. The method includes selectively enabling and disabling the plurality of output elements so that a direct current impedance of a parallel combination of the plurality of output elements is within a predetermined percentage of the impedance of the transmission line, and sizing the plurality of output elements to account for a predetermined range of PVT conditions, and selectively enabling and disabling the plurality of output elements to allow an impedance of the driver to be approximately equal to the impedance of the transmission line when an output voltage from the driver is approximately half the first supply voltage. The sizing of a plurality of transistors within the plurality of output elements is such that the direct current impedance of a parallel combination of the plurality of output elements is approximately equal to the impedance of the transmission line when the output voltage is half the supply voltage.

Method for a dynamic termination logic driver with improved impedance control

A dynamic termination logic driver, one that is capable of launching signals at a driving end of a transmission line and is capable of terminating signals at a receiver end of the transmission line, controls output impedance and includes within the driver an impedance circuit and slew rate control. Accordingly, a desired output impedance can be advantageously established and maintained over a wide range of variations in operating conditions, manufacturing processes and output voltage levels. Such a driver also advantageously limits any crowbar current, thereby reducing the overall power consumption of the driver with little, if any, degradation of driver performance. The driver includes a pull up circuit coupled to receive at least one of a plurality of control codes and the driver also includes a pull down circuit coupled to receive at least one of the plurality of control codes. The output impedance of the driver is further controlled during transitional phases of tuning on and turning off the pull down circuit and the pull up circuit under a plurality of process, voltage and temperature (PVT) conditions.

Method for a dynamic termination logic driver with improved slew rate control

A dynamic termination logic driver, the driver capable of launching signals at a driving end of a transmission line and terminating signals at a receiver end of the transmission line, controls slew rate over a wide range of variations in operating conditions, manufacturing processes and output voltage levels. Such a driver also advantageously limits any crowbar current, thereby reducing the overall power consumption of the driver with little, if any, degradation of driver performance. The driver includes a pull up circuit having an impedance, the pull up circuit including a pull up output circuit and a buffer circuit, the pull up output circuit including a parallel pull up circuit, a pull up output control circuit, and a pull up slew rate control circuit, wherein the parallel pull up circuit and the pull up output control circuit are coupled in parallel. The driver also includes a pull down circuit having an impedance, the pull down circuit including at least one pull down output circuit, the at least one pull down output circuit including at least one pull down slew rate control circuit, a parallel pull down circuit and a pull down output control circuit, wherein the parallel pull down circuit and the pull down output control circuit are coupled in parallel. The driver also includes a plurality of output elements within the pull up circuit and the pull down circuit, wherein the plurality of output elements are selectively enabled and disabled with a controlled slew rate. The selective enabling and disabling is based on an impedance control code.

Dynamic termination logic driver with improved slew rate control

A receiver is provided which quickly and efficiently recognizes signals by including with the receiver a resolving circuit which is coupled to a signal generation circuit which provides a differential current. The resolving circuit is coupled to a latching circuit. The resolving circuit can operate with supply voltage levels as low as one threshold voltage. Also, the signal setup and hold times are inherently very small due to the high intrinsic bandwidth of the receiver. Other advantages include reduced power consumption, high speed operation, good rejection of input noise and power supply noise, ability to resolve small (e.g., 1.0 m Volt) voltage differences, reduced capacitive loading, and the ability to function with a variety of types of drivers, including HSTL, DTL and PECL.

Differential receiver

A driver may be provided which controls the output slew rate a driver which includes within the driver a slew rate control circuit. Accordingly, a desired output slew rate can be advantageously established and maintained over a wide range of variations in operating conditions, manufacturing processes and output voltage levels. Such a driver also advantageously limits any crowbar current, thereby reducing the overall power consumption of the driver with little, if any, degradation of driver performance.

Output driver with improved slew rate control

A method for a driver may be provided which controls the output slew rate of a driver which includes within the driver an impedance control and a slew rate circuit. Accordingly, a desired output slew rate and a desired output impedance can be advantageously established and maintained over a wide range of variations in operating conditions, manufacturing processes and output voltage levels. Such a method also advantageously limits any crowbar current, thereby reducing the overall power consumption of the driver with little, if any, degradation of driver performance.

Growing community of inventors

Cupertino, CA, United States of America

Jonathan E Starr