International Business Machines Corporation

Visweswara Rao Kodali

Michael J Lee

Christopher McCall Durham

Salim Ahmed Shah

Sam Gat-Shang Chu

Harsh D Sharma

Douglas Ele Martin

Michael Kevin Ciraula

Johnny James LeBlanc

Kevin William McCauley

A method and implementing system is provided in which input signal specifications, element internal delays and output loads, for each element in a circuit design, are utilized in an iterative processing engine to objectively determine and provide a timing rule database for a circuit being designed. A schematic database netlist is run through a test model converter program to provide a test model database at a gate level for the test model design circuit. These data are processed by a designer through a workstation GUI and the result is applied to an I/O design testing function. The results of the I/O design testing function include a listing of patterns of input combinations which are needed to get listed outputs. The GUI prepares a sequence of stimuli to test the circuit with a timing simulator. Based on the output response of the timing simulator, delay relationships under various input and output load conditions are compiled.

Analyzing CMOS circuit delay

A method and apparatus is provided for enabling the transformation of a domino circuit to a static circuit without requiring the re-design of the chip or integrated circuit mask set. The domino circuit masks may be designed to include additional unconnected devices as appropriate which may be added or connected into the circuit after chip design release by changing only interconnection masks. Spare devices can be added and selectively used to make a domino circuit metal-mask programmable into a logically equivalent static circuit. In a first exemplary method, extra devices are added to, and/or existing devices are re-wired in the domino circuitry to make a complementary equivalent static gate. In a second exemplary methodology, the domino circuit is converted into a pseudo-NMOS circuit using devices already available in the circuit and modifying the circuit connections thereto.

Domino to static circuit technique

A method and device are disclosed for the reduction of the penalty associated with inserting a latch in a circuit which is utilized to implement an integrated circuit in a data-processing system. A semiconductor device is disclosed which includes a main latch circuit, a feedback latch circuit and an output terminal. The main latch circuit is capable of receiving an input data signal and an input clock signal. The main latch circuit generates a latch output signal in response to the input data and clock signals. The feedback latch circuit is capable of receiving the latch output signal from the main latch circuit and storing the latch output signal. The feedback latch circuit is capable of generating a feedback latch circuit output signal which is received by the main latch circuit to maintain the latch output signal. The output terminal of the device is coupled to the feedback latch circuit for outputting a device output signal which is equal to the feedback latch circuit output signal.

Method and device for the reduction of latch insertion delay

A system and method for initializing a threshold voltage level of a dynamic circuit prior to a transition of said dynamic circuit from a passive mode to an active mode. A dynamic logic circuit has a runtime operation that alternates between an active and a passive mode and includes at least one transistor having a floating body and a threshold voltage level. A switching device within the dynamic logic circuit forms a means from which the floating body draws an electric charge during the passive mode, thereby altering the threshold voltage level. The switching device receives a clock input signal during the dynamic circuit's active mode. Input selection means selectively replace the clock input signal with a pre-clock input signal into the switching device for a pre-determined period of time prior to a transition by the dynamic logic circuit from the passive mode to the active mode, such that the floating body may adequately discharge, thereby initializing the threshold voltage level prior to commencement of the active mode.

Initialization of floating body dynamic circuitry

A method and apparatus is effective to preserve logic state potential levels in logic circuitry notwithstanding alpha particle collisions. Cross-coupled circuitry, including active devices, are implemented in a complementary logic circuit arrangement to hold current logic values in the event of a premature switching such as a switching that may be induced by alpha particle collision with the semiconductor logic circuit. Stabilizing transistor switching devices are arranged to sense an inappropriate or premature switching initiation and respond thereto by operating to maintain the appropriate logic levels within the logic circuitry. In one embodiment, the internal node of an upper circuit in a dual-rail logic circuit is connected to a gate terminal of a cross-coupled PFET device in the lower circuit. The cross-coupled PFET device is operable to sense an initiated untimely switching action in the upper circuit and effect a re-application of the holding PFET in the upper circuit to re-establish the appropriate logic potential levels in the upper circuit.

Soft error protected dynamic circuit

A reduced-power integrated circuit includes a circuit data input, a circuit data output, and at least one row of dynamic logic. The row of dynamic logic includes a row clock input, a row data input, and a row data output coupled to the circuit data output, where a value received at the row data input is derived from the value at the circuit data input. The integrated circuit further includes a comparator that compares current and previous values at the circuit data input and a switch that selectively sets the row clock signal received at the row clock input to an inactive state and temporarily maintains the row clock signal in the inactive state in response to the comparator detecting that the current previous values of at the circuit data input are equivalent. Consequently, the row of dynamic logic does not (and need not) reevaluate the circuit data input value, and power dissipation is reduced.

Reduced power dynamic logic circuit that inhibits reevaluation of stable

Circuitry for eliminating charge sharing noise in MOS dynamic logic circuits is described. Dynamic logic circuits having stacks of MOS devices controlling the state of a common node defining the output logic state of the circuit are susceptible to charge sharing noise. This noise ultimately arises from leakage and stray capacitances at the nodes between MOS devices in each stack which the common node must supply. The noise is eliminated by employing MOS devices associated with the MOS devices in the stacks to couple the nodes between stack MOS devices to a supply voltage until their associated stack device changes logic state. On the changing state of the associated stack device, the node charging MOS device turns off, allowing the nodes to assume states defined by the input signals to the dynamic logic circuit.

Dynamic MOS logic circuit without charge sharing noise

A dynamic logic circuit is capable of receiving both dynamic and static input signals during both the precharge and evaluate phases of the logic circuit, and the static input signal is permitted to switch from both a low level to a high level and a high level to a low level during such stages and the logic circuit is still capable of correctly evaluating the implemented logical operation on the static and dynamic input signals. This is performed in CMOS by coupling a PFET between the internal precharge node and a voltage reference source where the gate electrode of the PFET device receives the static input signal.

Static-dynamic logic circuit

A multiplier circuit within a CPU has its selections of partial products reordered in a unique manner so that shift left capabilities are eliminated and the hardware is required to only perform shift right operations. This allows for reduced circuit sizes in several components within the multiplier circuit in order to save area, speed computation time, and reduce power consumption on the chip.

System and method for multiplying in a data processing system

A 'no select state' is implemented with self-resetting CMOS logic circuitry so as to essentially disable the resetting function of this logic circuitry when the logic circuitry is in an idle state. As an example, within a multiplier circuit in a processor, the selection inputs to a multiplexor circuit are de-selected when there is no need for the multiplier circuitry.

System and method for power management in self-resetting CMOS circuitry

A forward single-rail self-resetting reset circuit is utilized to reset a logic circuit to a selected state subsequent to each iteration of a logical operation on inputted data into the logic circuit. The reset circuit receives at least one of the data inputs and its complement signal so that the reset signal produced by the reset circuit is activated regardless of the voltage level of the data input signals.

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Austin, TX, United States of America

Visweswara Rao Kodali