Patents by Inventor Paul W. Chung
Paul W. Chung has filed for patents to protect the following inventions. This listing includes patent applications that are pending as well as patents that have already been granted by the United States Patent and Trademark Office (USPTO).
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Patent number: 6340882Abstract: An accurate current source with an adjustable temperature dependence. This type of current source is used in silicon Integrated Circuit (IC) designs requiring supporting reference-voltage sources and/or reference-current sources which may be designed with or without temperature dependence. The circuit generates an accurate current with temperature independence along with another accurate current source with temperature dependence using only one precision external resistors. For the temperature-dependent current source, the temperature dependence can be controlled by setting a temperature dependence factor (TDF).Type: GrantFiled: October 3, 2000Date of Patent: January 22, 2002Assignee: International Business Machines CorporationInventors: Paul W. Chung, John T. Contreras
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Patent number: 5422642Abstract: An analog receiver circuit suitable for use with a flash analog-to-digital converter is described. A first stage of the receiver acts essentially as a voltage follower, receiving the centertap voltage of a flash A/D converter resistor ladder, and maintaining an internal reference voltage substantially equal to the centertap voltage over time. A second stage of the analog receiver acts as centering means, receiving an analog signal and centering it with respect to the internal reference voltage provided by the first stage. The receiver is thus able to provide an analog signal to the flash A/D converter which is dynamically centered with respect to the converter's operating voltage, thereby reducing DC offset. Moreover, introducing the analog signal at the second stage minimizes the bandwidth-limiting elements between this input signal and the DC-centered output signal. Thus DC offset is further reduced and operating frequencies of 500 MTz or greater are possible.Type: GrantFiled: June 22, 1993Date of Patent: June 6, 1995Assignee: International Business Machines CorporationInventors: Paul W. Chung, John E. Gersbach, Bac Pham, Karl Hense, Pete Granata
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Patent number: 5391935Abstract: An assertive latching flip-flop circuit is provided which prevents the occurrence of metastable outputs. The circuit comprises a single flip-flop which is comprised of standard switching transistors which are switched by a clocking mechanism having no additionally introduced delay. The circuit includes an imbalancing element which is coupled to a latching portion of the circuit. The latching portion of the circuit comprises a pair of cross-coupled transistors, in current mode embodiments of the invention, or a pair of cross-coupled inverters, in voltage mode embodiments of the invention. The imbalancing element introduces an electrical disturbance on the input line to one of the latching transistors or inverters. The imbalancing element is a capacitor in voltage mode embodiments of the invention and an additional transistor in current mode embodiments.Type: GrantFiled: July 22, 1993Date of Patent: February 21, 1995Assignee: International Business Machines CorporationInventors: John E. Gersbach, Paul W. Chung
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Patent number: 5057785Abstract: A method and circuitry for suppressing additive transient disturbances in an analog differential input signal, such disturbances being due, for example, to thermal asperity transients caused by an MR transducer contacting a moving storage surface. The input data signal is algebraically summed with a corrective feedback signal for providing as output signal. The output signal is fed back to a circuit including an envelope detector and differentiator and converted into another signal that is the derivative of an amplitude envelope corresponding to the output signal. Nonlinear signal-adaptive filter means converts said other signal into the corrective feedback signal, which substantially replicates the additive transient disturbance and is subtracted from the data input signal to render the output signal substantially free of the transient disturbance.The input, output and corrective signals are preferably differential signals.Type: GrantFiled: January 23, 1990Date of Patent: October 15, 1991Assignee: International Business Machines CorporationInventors: Paul W. Chung, Michael O. Jenkins, Stephen A. Jove, Klaas B. Klaassen, Paik Saber, Jacobus C. L. van Peppen
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Patent number: 5012246Abstract: A high performance, low power analog to digital converter is designed in BIFET technology utilizing the high gain, high performance of a bipolar comparator and the low power of a CMOS latch and CMOS encoding logic circuits. Using a FET dynamic latch, metastability is avoided, significantly reducing soft error rate.Type: GrantFiled: January 31, 1990Date of Patent: April 30, 1991Assignee: International Business Machines CorporationInventors: Paul W. Chung, Karl R. Hense, Kim Y. Nguyen
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Patent number: 4929918Abstract: A method and means for setting the free-running frequency of a voltage controlled oscillator (VCO) without requiring laser trimming or the like is described. The VCO forms part of an interconnected phase-locked loop (PLL) and frequency-locked loop (FLL). At system power on, the PLL is automatically disabled and a digital-to-analog (DAC) in the PLL is set to a value corresponding substantially to the center of a preselected lock range. The FLL, which includes a second DAC, then operates to generate a bias voltage for incrementing or decrementing the VCO output frequency until the VCO pulse count stored in a register equals an expected count; whereupon the VCO will be set at its free-running frequency. When the PLL is enabled, a phase error generator generates a digital phase error signal from the input data. A digital integrator converts the phase error signal to a digital frequency error signal.Type: GrantFiled: June 7, 1989Date of Patent: May 29, 1990Assignee: International Business Machines CorporationInventors: Paul W. Chung, Ralph L. Gee, Luke C. K. Lang, Paik Saber
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Patent number: 4859880Abstract: A CMOS differential driver includes a differential amplifier with two input terminals. Complementary transfer gates selectively connect high and low voltage input terminals to the amplifier input terminals. The complementary transfer gates are controlled by identical logic input signals to provide exactly complementary voltage inputs to the differential amplifier circuit, so true complementary output signals are provided at the amplifier output terminals.Type: GrantFiled: June 16, 1988Date of Patent: August 22, 1989Assignee: International Business Machines CorporationInventors: Paul W. Chung, Niantsu N. Wang
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Patent number: 4812784Abstract: A voltage controlled oscillator (VCO) having high temperature stability and wide voltage/frequency linearity is provided. The VCO comprises a multivibrator being switched by a bipolar type device, and temperature fluctuations of the bipolar type means are compensated by a FET current source coupled thereto. To provide a linear relationship of frequency vs. voltage over wide voltage range, the bipolar device is further regulated by a plurality of resistor and diode networks.Type: GrantFiled: November 19, 1987Date of Patent: March 14, 1989Assignee: International Business Machines CorporationInventors: Paul W. Chung, Paik Saber
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Patent number: 4808840Abstract: An edge-triggered latch is disclosed which has a low setup time and almost no metastability problem. It comprises a dynamic sensing means for detecting the voltage level of the data signal and at least one dynamic buffer for amplifying said detected voltage level into one of two logic levels recognizable by a static latch wherein the sampled result is stored.Type: GrantFiled: November 20, 1987Date of Patent: February 28, 1989Assignee: International Business Machines CorporationInventors: Paul W. Chung, Niantsu N. Wang
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Patent number: 4649516Abstract: A dynamic row buffer circuit is disclosed for a dynamic random access memory (DRAM) chip which enables the DRAM chip to be used for special function applications. The dynamic row buffer comprises a row buffer master register and a row buffer slave register. The row buffer master register comprises a plurality of master circuits (M1) and a plurality of slave circuits (S1). Likewise, the row buffer slave register comprises a plurality of master circuits (M2) and a plurality of slave circuits (S2). The row buffer master register is parallel load and parallel read-out with the outputs of the master register slave circuits being connected to the master circuits of the slave register. The row buffer slave register is a parallel load, serial read-out register with the output being shifted out of a secondary output port. The entire row buffer can be isolated from the memory array, and when so isolated, the memory array can be accessed through the primary input/output port in the same way as in an ordinary DRAM chip.Type: GrantFiled: June 1, 1984Date of Patent: March 10, 1987Assignee: International Business Machines Corp.Inventors: Paul W. Chung, Richard E. Matick, Daniel T. Ling
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Patent number: 4496852Abstract: A clock generator circuit for producing with very little power dissipation an output clock signal having levels determined by positive and negative power supply levels from an input clock signal having levels determined by the positive power supply level and ground. In a low state of the input clock signal, an upper or first transistor of an output transistor pair connected in series between positive and negative power supply levels is turned off by applying a ground level to the base thereof, while the lower or second transistor of the output transistor pair is turned off by applying a positive potential to its base. When the input clock signal makes a transition from the low state to the high state, a bootstrap capacitor is charged between the positive and negative power supply levels to provide a boosted positive voltage to turn on the upper transistor. While the bootstrap capacitor is charging, the base of the lower transistor is lightly grounded to partially turn it on.Type: GrantFiled: November 15, 1982Date of Patent: January 29, 1985Assignee: International Business Machines CorporationInventors: Eugene M. Blaser, Paul W. Chung, Ramesh C. Varshney