Ami Semiconductor, Inc.

Gould Inc.

Brian R Kauffmann

James Robert Brown

Charles A Edmondson

Kelvin K Hsueh

Gerardus F Riebeek

James Antone

Melvin W Stene

Systems and methods are disclosed for distributing memory within one or more regions of circuitry that perform logic functions (or other types of functions that require dense interconnect structures) on an integrated circuit. The distributed memory reduces high density routing congestion, allows increased logic utilization, and provides areas for additional interconnect structure. Various techniques are also disclosed for accessing the memory.

Distributed memory and logic circuits

An SRAM memory includes a pull-up device coupled to each row of word lines in an array of SRAM cells. The pull-up devices are sized such that when a row is selected, the time for the associated word line to fully charge is sufficiently slow such that data stored in the selected SRAM cells are not corrupted during a read operation. By slowly charging the word lines, the corresponding access transistors are also slowly turned on, resulting in the coupled bit lines slowly charging or discharging from the data stored in the SRAM cell. Because there is not a sudden large charge transfer between the stored data and the coupled bit line, the data will not be corrupted during a read operation, and read precharge circuitry is not required.

Static random access memory (SRAM) without precharge circuitry

A delay lock loop circuit is disclosed which includes a delay block which receives the clock signal and delays the clock signal by a selected amount to generate the delayed clock signal. A phase detector receives the clock signal and the delayed clock signal, compares the phases of the two signals and generates a phase comparison signal. A lock detector receives the clock signal and the delayed clock signal, compares the timing of the two signals and generates a potential lock indication signal. A controller receives the phase comparison signal and the potential lock indication signal and provides a delay control signal to the delay block to change the selected delay amount in response to the phase comparison signal. The controller interrupts the clock signal to the delay block for a selected interval in response to the potential lock indication signal, and generates a true lock indication signal in response to the potential lock indication signal after the interruption of the clock signal to the delay block. The delay lock loop circuit is capable of handling a wide range of clock frequencies and a step increase or decrease in the clock frequency.

Delay lock loop with wide frequency range capability

In a high-voltage output buffer, a self-adjusting bias generator is provided which is capable of automatically adjusting the applied bias voltages in the output buffer so as to enhance the output buffer performance. Under normal or high supply voltage conditions, the bias generator provides a first set of bias voltages to the series-connected transistors in the output buffer. Under low supply voltage conditions, the bias generator provides a second set of bias voltages to the various series-connected transistors.

CMOS self-adjusting bias generator for high voltage drivers

A highly stable high-voltage output buffer is provided which may be manufactured using standard CMOS technology. As part of the invention, the effects of voltage drift at one or more of the nodes formed between series connected P or N-channel MOSFET devices are generally reduced or eliminated. The present invention includes compensation circuitry which reduces the effects of parasitic coupling within the MOSFET devices, and which serves to compensate for any voltage drift which may occur at the nodes between series connected devices. In addition, the present invention provides a method and apparatus for increasing the current sourcing capability of a CMOS high-voltage output buffer, even under low supply V.sub.vf conditions, without necessarily increasing the size of the output device. Furthermore, the present invention provides a method and apparatus for reducing the effects of coupling along a shared bias line between a plurality of high-voltage output buffers in accordance with the present invention.

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Pocatello, ID, United States of America

Brian R Kauffmann