International Business Machines Corporation

Dana Marie Woeste

James David Strom

Steven John Baumgartner

Eric John Lukes

Patrick Lee Rosno

Timothy Clyde Buchholtz

Daniel Mark Dreps

Anthony Richard Bonaccio

Sergey Vladimirovich Rylov

Mounir Meghelli

David W Siljenberg

Charles Porter Geer

Andrew Benson Maki

Thomas W Liang

Andrew Douglas Davies

Daniel Guy Young

Bruce George Rudolph

Thomas Pham

A design structure embodied in a machine readable medium used in a design process includes a current mirror circuit that includes a reference current source that generates a reference current, a reference transistor, a mirror transistor and a ratioed body bias feedback unit. The reference transistor has a first node that is coupled to the output of the reference current source, a gate that is coupled to the first node and a second node coupled to a common voltage. The mirror transistor has a gate coupled to the first node. The ratioed body bias feedback unit generates a body bias voltage coupled to the body of the reference transistor and the body of the mirror transistor. The ratioed body bias feedback unit is configured to adjust the body bias voltage in relationship to the common voltage so that the reference transistor and the mirror transistor each have a threshold voltage within a predefined range.

Ratioed feedback body voltage bias generator

A design structure for a high speed computer processor system includes a high speed interface for a graphics processor. In a preferred embodiment, the high speed interface includes a front side bus (FSB) that interfaces to a similar high speed interface on the graphics processor.

Architecture for a physical interface of a high speed front side bus

A phase locked loop generates an output corresponding to a source synchronous input and an input link clock signal. A phase locking feedback system receives the input and an input link clock signal and detects phase deviations between the output and the input. The phase locking feedback system also adjusts an adjusted clock signal based on the phase deviations thereby causing the phase locking feedback system to generate the output so that the output has a steady phase relationship with the input. A first mechanism causes the phase locking feedback system not to track phase deviations between the output and the input upon occurrence of a first predefined event, thereby maintaining the adjusted clock signal at a current state.

Unlock mode in source synchronous receivers

A current mirror circuit includes a reference current source that generates a reference current, a reference transistor, a mirror transistor and a ratioed body bias feedback unit. The reference transistor has a first node that is coupled to the output of the reference current source, a gate that is coupled to the first node and a second node coupled to a common voltage. The mirror transistor has a gate coupled to the first node. The ratioed body bias feedback unit generates a body bias voltage coupled to the body of the reference transistor and the body of the mirror transistor. The ratioed body bias feedback unit is configured to adjust the body bias voltage in relationship to the common voltage so that the reference transistor and the mirror transistor each have a threshold voltage within a predefined range.

A high speed computer processor system includes a high speed interface for a graphics processor. In a preferred embodiment, the high speed interface includes a front side bus (FSB) that interfaces to a similar high speed interface on the graphics processor.

A method and a low voltage, complementary metal oxide semiconductor (CMOS) circuit are provided for generating voltage and current references with a low voltage power supply. A voltage generating circuit provides a voltage reference and is formed by a plurality of CMOS transistors and a resistor. An operational amplifier includes a differential pair of CMOS transistors. The first voltage reference is applied to an input of the differential pair of transistors and an output of the differential pair of transistors providing a second voltage reference. The operational amplifier includes a plurality of current reference transistors. A first voltage generating circuit generates a first voltage and a second voltage generating circuit generating a second voltage. The first and second voltage generating circuits are formed by a plurality of CMOS transistors. The generated first and second voltages are applied to the voltage reference generating circuit and current reference transistors.

Method and low voltage CMOS circuit for generating voltage and current references

A CMOS signal transmission system for sending a large amount of CMOS signals into a separate quiet analog power domain. Transmission system comprises a converter sub-system which provides at least another device stage through which noise in the CMOS signals must flow and be attenuated to provide converted CMOS signals and a multiplexer coupled to the converter wherein the multiplexer receives converted CMOS signals from the converter sub-system and also receives delayed path control signals. The converter comprises a constant current source for providing a high level voltage reference and a constant current, two complimentary pass gates, and two sets of components for providing paths to ground from the constant current source through the two complimentary pass gates. When CMOS input signal is high and Complimentary CMOS input signal is low, the pass gate comprising transistors T and T is on and transistors T and T are off and connection BSEL is pulled high turning on bipolar transistor Q allowing current to flow through Q and pulling net SB low and selecting inputs B , B to be transferred to ECL Differential Outputs. Likewise, when CMOS input signal is low and Complimentary CMOS input signal is high, pass gate comprising transistors T and T is on, and transistors T and T are off, and connection ASEL is pulled high turning on bipolar transistor Q allowing current to flow through Q and pulling net SA low and selecting inputs A , A to be transferred to ECL Differential Outputs.

Method and system for sending large numbers of CMOS control signals into a separate quiet analog power domain

An apparatus and method for distributing a clock signal within circuitry disposed on a number of separate system cards includes a first system card that generates a reference clock signal representative of a fixed delay of a system clock signal. A number of variable clock signals are produced using the system clock signal. Each of a number of system cards separate from the first system card receive one of the variable clock signals. A delay associated with the reference clock signal is typically longer than a delay associated with each of the variable clock signals. The phase of each of the variable clock signals is adjusted to a substantially in-phase relationship with respect to the reference clock signal in response to a phase difference between the reference clock signal an output signal received from each of the separate system cards. Producing each of the variable clock signals may involve selecting between a first delay line and a second delay line, and then producing the variable delay signal using the selected first or second delay line. A delay factor of the non-selected first or second delay line may be changed by varying a resistance and a current of one or more delay elements of the non-selected first or second delay lines. The circuitry is selectably operable in a slave or buffer-type clock repowering mode or an adaptive mode. The variable clock signals and the output signals may respectively comprise low voltage differential signals (LVDS) or CMOS level signals.

Multiple-mode clock distribution apparatus and method with adaptive skew compensation

A high speed differential output driver is provided with increased voltage swing and predrive common mode adjustment. The high speed differential output driver includes a differential input with a voltage amplifier receiving the differential input signal and a common mode adjustment signal and providing an adjustable voltage amplified signal. An emitter follower is coupled to the voltage amplifier. The emitter follower provides a level shifted voltage amplified signal. A driver is coupled to the emitter follower receiving the level shifted voltage amplified signal and providing a driver output signal.

High speed differential output driver with increased voltage swing and predrive common mode adjustment

An apparatus and method for delaying a signal using a variable delay line circuit. A variable delay line circuit includes first and second delay lines, each including a plurality of delay elements. A multiplexer is coupled to respective outputs of the first and second delay lines and selectively couples the output of one of the first or second delay lines to an output of the multiplexer. A control circuit is coupled to the multiplexer and the first and second delay lines, and controls the multiplexer so as to produce a delayed signal at the multiplexer output using one of the first or second delay lines, and changes a delay factor of the other one of the first or second delay lines by varying a resistance and a current of one or more delay elements of the other one of the first or second delay lines. A reference voltage source is coupled to each of the delay elements and provides a reference voltage maintained at a substantially constant amplitude with respect to the power supply to each of the delay elements. The delayed signal may be a differential signal. Each of the delay elements may include one or more adjustable loads or adjustable current sources. An adjustable load may be implemented using P-FETs. In one embodiment, at least one of the delay elements of the first and second delay lines includes a plurality of selectable delay devices, each of which is associated with one of a plurality of selectable delay factors.

Digitally controlled differential delay line circuit and method of

An improved phase locked loop (PLL) circuit is provided for use in microprocessor clock generation. A ring oscillator provides an output frequency signal. A voltage to current converter converts differential control voltages to a variable reference current applied to the ring oscillator. A range control reference current generator applies a range control reference current to the ring oscillator. A range control operatively controls the range control reference current generator to sequentially change the range control reference current applied to the ring oscillator. A lock detector coupled to the range control compares the output frequency signal and a reference frequency signal and responsive to the compares signals applies a locked signal to the range control. Responsive to an applied locked signal, the range control stops changing ranges. The phase locked loop (PLL) circuit automatically sweeps through multiple frequency subranges responsive to the range control. A control signal is applied to the voltage to current converter for selectively controlling an operational mode of the voltage to current converter from a squelched operational mode to an unsquelched operational mode after a set time period. This control signal also is applied to the range control, so that the range control stops changing ranges.

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Mantorville, MN, United States of America

Dana Marie Woeste