Abstract:
An apparatus and method for decorrelating pairs of mutually contaminated channels in a multi-channel digital signal including two identical data processing paths and a feedback path. Each pair of mutually contaminated channels consists of a first contamined channel and a second contaminated channel. Initially, first and second shifted signals are generated by shifting the original contaminated signal such that the first shifted signal has the first contaminated channel centered at zero frequency and the second shifted signal has the second contaminated channel centered at zero frequency. Each of the first and second shifted signals are coupled to one of the two identical signal processing paths. The first path generates an error corruption component corresponding to the first shifted input signal and subtracts this corruption component from the second shifted signal in order to generate a third decorrelated digital signal. The second path generates an error corruption component corresponding to the second shifted input signal and subtracts it from the first shifted signal in order to generate a fourth decorrelated digital signal. The feedback path generates a current average error correlation factor by multiplying the third and fourth to generate an instantaneous error factor and summing this with the previous average error correlation factor for all samples. The current average error correlation factor is used to generate the first and second error corruption components. Each of the corrupted channels in the original contamined digital signal are decorrelated when the third and fourth digital signals are decorrelated.
Abstract:
A circuit for protecting an interconnect line from certain undesirable voltage swings for a given input signal. A transmission gate is coupled in series between the input signal and the interconnect line. The transmission gate's input terminal is coupled to the input signal, its output terminal is coupled to the interconnect line, and its control terminal is coupled to the output of an inverter. The input of the inverter is coupled to the input signal. When the input signal transitions to a voltage that exceeds the trip point of the inverter, the inverter outputs a signal that disables the transmission gate such that the node is isolated from the input signal. A PFET transmission gate is utilized for protection against voltages that are too negative, and an NFET transmission gate is utilized for protection against voltages that are too positive. The inverter may be replaced by a comparator having its positive input coupled to a reference voltage and its negative input coupled to the input signal. The reference voltage determines the trip point of the protection circuit. The protection circuit may also include first and second biased MOS devices (having different channel types) coupled between first and second working potentials. The gate of the first MOS device is coupled to the input signal and the gate of the second MOS device is coupled to the output of the inverter. The MOS devices function as a conductive voltage divider network to establish a voltage on the node when the node is isolated from the input signal.
Abstract:
An apparatus for reducing transmisson delay times when transmitting differential signals in an integrated circuit along long interconnect lines (10, 11) includes a current mode line driver which converts the differential signal to be transmitted into a signal that has a relatively low peak-to-peak voltage and large differential current changes. A receiver responsive to differential current changes converts the signal back into an output differential signal having peak-to-peak voltages adaptable to subsequent logic stages. A feedback circuit (Q5, Q6) coupled to the interconnect lines (10, 11) and the receiver functions to clamp the interconnect lines (10, 11) to a predetermined voltage while allowing the output differential signal to have peak-to-peak voltages greater than the predetermined voltage.
Abstract:
An ECL-to-CMOS level translator and BiCMOS buffer are described. The current supplied from the first input PMOS transistor (P1) is the input current to a current mirror comprising the first and second NMOS transistors (N1 and N2). The current mirror controls the current sourcing and sinking capability of the translator. Third and fourth NMOS transistors (N3 and N4) are coupled to the first and second NMOS transistors in the current mirror and function to vary the source-to-body voltage of the first and second NMOS transistors and consequently their gain which results in increased current drive and sinking capability. The BiCMOS differential buffer of the present invention provides a differential output signal on first and second output nodes (115 and 215). It is comprised of first and second cross-coupled buffers (100B and 200B). Cross-coupling the buffers results in improved high-to-low transition times.
Abstract:
An improved BiCMOS logic circuit (70) utilizes an emitter-coupled pair of bipolar transistors (21, 22) for differentially comparing an input signal (Vin) with a logic reference level (VBIAS). Each of the bipolar transistors are resistively loaded by a network of p-channel metal-oxide-semiconductor (PMOS) transistors (26, 27) coupled in parallel. At least one of the parallel combination of transistors has its gate coupled to a control signal (VREF2) providing a variable load resistance. The control signal is preferably provided by a feedback network (52, 53) which maintains a constant voltage swing across the network over temperature.
Abstract:
A microscopic laminar-flow heat exchanger, well-suited for cooling a heat generating device such as a semiconductor integrated circuit, includes a plurality of thin plates (10), laminated together to form a block (18). Each plate has a pair of holes (14, 15) cut through the plate such that when the block is formed, the holes align to form a pair of coolant distribution manifolds. The manifolds are connected via the plurality of microscopic channels formed from the recessed portions during the lamination process. Coolant flow through these channels effectuates heat removal.
Abstract:
A method for forming a BICMOS integrated circuit having MOS field effect transistors and bipolar junction transistors is disclosed. The process comprises first defining separate active areas, forming a gate dielectric layer and a first layer of polysilicon. This polysilicon is then selectively etched to form a plurality of equally-spaced first polysilicon members comprising the gates (33, 34) of the MOS transistors and the extrinsic base contacts (35) of the NPN transistors. After insulating the first polysilicon members, an additional layer of polysilicon is deposited over the substrate to replanarize the entire wafer surface. The additional layer of polysilicon is then etched to form a plurality of second polysilicon members (65, 66, 67, 68, 69). Impurities are diffused from the polysilicon members to form source/drain regions (73, 74, 75, 76) of the MOS transistors and the extrinsic base (81) and emitter (77) regions of the NPN transistors. The final processing steps include providing the interconnection of the MOS and NPN transistors.
Abstract:
Expandably wide operations are disclosed in which operands wider than the data path between a processor and memory are used in executing instructions. The expandably wide operands reduce the influence of the characteristics of the associated processor in the design of functional units performing calculations, including the width of the register file, the processor clock rate, the exception subsystem of the processor, and the sequence of operations in loading and use of the operand in a wide cache memory.
Abstract:
There is disclosed a photolithography mask and method of making the same that utilizes serifs to increase to correspondence between an actual circuit design and the final circuit pattern on a semiconductor wafer. The mask uses a plurality of serifs having a size determined by a resolution limit of the optical exposure tool used during the fabrication process. The serifs are positioned on the corner regions of the mask such that a portion of surface area for each of the serifs overlaps the corner regions of the mask. The size of the serifs is about one-third the resolution limit of said optical exposure tool. About 33 to about 40 percent of the total surface area of the serifs overlap the corner regions of the mask.
Abstract:
A virtual memory system including a local-to-global virtual address translator for translating local virtual addresses having associated task specific address spaces into global virtual addresses corresponding to an address space associated with multiple tasks, and a global virtual-to-physical address translator for translating global virtual addresses to physical addresses. Local-to-global virtual translation is performed by either mapping local virtual addresses to a single global virtual address space or to multiple global virtual address spaces. The local-to-global virtual translator includes a cell which corresponds to each local address space for performing the translations. Separate cache and tag structures are employed for handling data and instruction memory accesses. The cache can be configured into a buffer portion or a cache portion for faster cache accesses. Protection information is provided by each of the local virtual-to-global virtual address translator, the global virtual-to-physical address translator, the cache tag storage, or a protection information buffer depending on whether a cache hit, cache miss, or buffer access occurs during a given data or instruction access. Memory area privilege protection is also achieved by employing a gateway instruction which generates an address to access a gateway storage area.