International Business Machines Corporation

Hongfei Wu

Kai D Feng

Sebastian Theodore Ventrone

Joseph Andrew Iadanza

Gary Dale Carpenter

Kevin John Nowka

Douglas Willard Stout

Francis H Chan

Bret Roberts Dale

William L Bucossi

Songtao Xu

Jason Chung

A digital clock generation circuit (and a method for operating the same). The digital clock generation circuit includes a first, a second, a third differential comparator circuits. The first differential comparator circuit receives the positive differential clock signal and a reference voltage, and generates a first output signal. The second differential comparator circuit receives the positive and negative differential clock signal, and generates a second output signal. The third differential comparator circuit receives the reference voltage and the negative differential clock signal, and generates a third output signal. A high-high detecting circuit receives the first output signal, and the third output signal, and generates an Enable signal. The digital clock generation circuit further includes a latch circuit which receives the second output signal, and the Enable signal and generates a digital clock signal. The latch circuit comprises a latch with glitch or noise immunity.

Receiver circuits for generating digital clock signals

A method and device program a dual edge programmable delay unit, that responds to an input signal with a rise time and a fall time, includes a buffer which receives the input signal and provides an output signal with programmed variable delays between the rise and fall times of the output signal. Programmable control sources (PCS) provide separate control inputs to a buffer. The FTPCS charges a capacitor in the buffer when the input signal changes from high to low to adjust time delay before the fall of the buffer output signal. The RTPCS discharges the capacitor in the buffer when the input signal changes from low to high to adjust time delay before the rise of the buffer output signal.

Dual edge programmable delay unit

A structure and method for eliminating glitches at the output of a receiver receiving signals sent to one end of a bi-directional, simultaneous transmission line. The receiver comprises two comparators, a logic circuit, a glitch detector, and a programmable delay unit. The two comparators convert a three-state digital signal on the transmission line into two two-state digital signals so that the logic circuit can understand. When a glitch occurs at the output of the logic circuit, also the output of the receiver, caused by the transitions on the output of one of the comparators and a first signal being sent to the other end of the transmission line reaching the logic circuit not at the same time, the glitch detector causes the programmable delay unit to adjust delay to the propagation path of the first signal to the logic circuit so as to eliminate the cause of the glitch.

Glitch-free receivers for bi-directional, simultaneous data bus

In order to reduce slew rate and minimize delay skew, the invention adds a pull-down booster circuit connected to the gate of the driving transistor and/or a pull-up booster circuit connected the gate of the driving transistor. The pull-down booster circuit is adapted to dynamically pull-down the voltage at the gate of the driving transistor when the voltage level at the input to the logical enable device changes from a first voltage (e.g., a logical &ldquo;0&rdquo;) to a second voltage (e.g., a logical &ldquo;1&rdquo;). The pull-up booster circuit is adapted to dynamically pull-up the voltage at the gate of the driving transistor when the voltage level at the input to the logical enable device changes from the second voltage to the first voltage.

Dynamic driver boost circuits

An I/O driver comprising: a circuit adapted to be powered by a first power supply. The circuit is adapted to receive a first signal referenced to the voltage of a second power supply and is adapted to convert the first signal to a second signal of the same logical value as the first signal and referenced to the voltage of the first power supply. The circuit is adapted to maintain the second signal on an output of the I/O driver when the second power supply is powered off.

Low power low voltage transistor&mdash;transistor logic I/O driver

The present invention provides a receiver device having multiple voltage supplies that allows the output stage of the receiver device to go to a safe state whenever its voltage is disconnected or powered-down, independent of any of its normal control circuits. Furthermore, the isolation of the multiple voltage supplies provides a low skew at the output of the receiver device.

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Colchester, VT, United States of America

Hongfei Wu