Patent application number | Description | Published |
20090037626 | Multi-drop bus system - A multi-drop bus system and a method for operating such a system. The system includes a multi-drop bus having at least one bus line, each bus line being made up of a multiple of line segments. Each of the line segments terminates at a drop point and each drop point is coupled to a load impedance. The characteristic impedance of a line segment is matched to the equivalent impedance presented by the load impedance in combination with the characteristic impedance of a following segment, or is matched to the load impedance if there is no following segment. | 02-05-2009 |
20090059642 | Memory Controller With Multi-Modal Reference Pad - A memory controller operates in two modes to support different types of memory devices. In a first mode, the memory controller distributes a dedicated reference voltage with each of a plurality of signal bundles to a corresponding plurality of memory devices. The reference voltages are conveyed using pads that are alternatively used for e.g. timing-reference signals in a second mode, so the provision for bundle-specific reference voltages need not increase the number of pads on the memory controller. | 03-05-2009 |
20090089557 | UTILIZING MASKED DATA BITS DURING ACCESSES TO A MEMORY - Embodiments of an apparatus that uses unused masked data bits during an access to a memory are described. This apparatus includes a selection circuit, which selects data bits to be driven on data lines during the access to the memory. This selection circuit includes a control input that receives a data mask signal, which indicates whether a set of data bits is to be masked during the access to the memory. During the access to the memory, the selection circuit selects either the set of data bits to be driven when the data mask signal is not asserted, or an alternative set of values to be driven when the data mask signal is asserted. | 04-02-2009 |
20100309964 | ASYMMETRIC COMMUNICATION ON SHARED LINKS - Embodiments of a system that communicates bidirectional data between two devices via shared links is described. In this system, data is transmitted on the shared links by one of the devices using single-ended drivers, and corresponding symbols are received on the shared links by the other device using differential comparison circuits. The data may be encoded as a series of parallel codewords prior to transmission. Each shared link may communicate a respective symbol in each codeword, which can have one of two possible logical values (e.g., a logic 0 or a logic 1). The corresponding symbols received by the other device may comprise a parallel symbol set, and each of the differential comparison circuits may compare symbols received on pairs of the shared links. A decoder in the other device may decode a respective parallel symbol set from the outputs of the differential comparison circuits to recover the encoded data. | 12-09-2010 |
20110025374 | Multi-Drop Bus System - A multi-drop bus system and a method for operating such a system. The system includes a multi-drop bus having at least one bus line, each bus line being made up of a multiple of line segments. Each of the line segments terminates at a drop point and each drop point is coupled to a load impedance. The characteristic impedance of a line segment is matched to the equivalent impedance presented by the load impedance in combination with the characteristic impedance of a following segment, or is matched to the load impedance if there is no following segment. | 02-03-2011 |
20110051854 | ERROR DETECTION AND OFFSET CANCELLATION DURING MULTI-WIRE COMMUNICATION - Embodiments of a circuit are described. In this circuit, a receive circuit includes M input nodes that receive a set of M symbols on M links during a time interval, where the set of M symbols are associated with a codeword. Moreover, the receive circuit includes a decoder, coupled to the M input nodes, that determines the codeword in a code space based on the set of M symbols and that decodes the codeword to a corresponding set of N decoded symbols. Additionally, the receive circuit may include a detector that detects an imbalance in a number of instances of a first value in the set of M symbols, and a number of instances of a second value in the set of M symbols, and, if an imbalance is detected, that asserts an error condition. | 03-03-2011 |
20110084737 | FREQUENCY RESPONSIVE BUS CODING - A data system permits bus encoding based on frequency of the bus and the frequency of switching on the bus so as to avoid undesirable frequency conditions such as a resonant condition or interference with other electrical devices. Transmission frequencies along one or more busses are monitored and used to control the encoding process, for example, an encoding process based on data bus inversion (DBI). The use of both a measure of an absolute number of logic levels (“DBI_DC”) and a measure of a number of logic level transitions relative to a prior signal (“DBI_AC”) provides a measure of control that may be used to compensate for both main and predriver switching noise. | 04-14-2011 |
20110102043 | REDUCING POWER-SUPPLY-INDUCED JITTER IN A CLOCK-DISTRIBUTION CIRCUIT - A system for compensating for power-supply-induced jitter (PSIJ) in a chain of clock buffers within an integrated circuit is described. During operation, the system couples a first supply voltage from a first voltage source to a supply node of each clock buffer in a first chain of clock buffers. Note that a change in the first supply voltage causes a change in a first propagation delay associated with the first chain of the clock buffers. The system also couples a second chain of clock buffers in series with the first chain of clock buffers. The system then couples the first voltage source to each clock buffer in the second chain of clock buffers through coupling circuitry. Next, the system adjusts the coupling circuitry so that the change in the first supply voltage from the first voltage source causes a change in a second propagation delay associated with the second chain of the clock buffers, wherein the change in the first propagation delay and the change in the second propagation delay are complementary. | 05-05-2011 |
20110293041 | Receiver Resistor Network for Common-Mode Signaling - A receiver circuit to receive signals from first and second pairs of transmission lines includes first and second interfaces, each with first and second input nodes to receive respective signals. The receiver circuit also includes a resistor network with first, second, third, and fourth resistive elements. The first and second resistive elements are each connected between the input nodes of a respective interface. The third and fourth resistive elements each include a pair of resistors connected in series between the input nodes of a respective interface, and an intermediate node between the resistors. The intermediate nodes are connected to an AC ground. The receiver circuit further includes a differential amplifier with first and second inputs coupled respectively to the first and second interfaces and an output to provide a signal derived from common mode components of the signals received at the input nodes. | 12-01-2011 |
20110314200 | BALANCED ON-DIE TERMINATION - Termination of a high-speed signaling link is effected by simultaneously engaging on-die termination structures within multiple integrated-circuit memory devices disposed on the same memory module, and/or within the same integrated-circuit package, and coupled to the high-speed signaling link. | 12-22-2011 |
20120169412 | FAST POWER-ON BIAS CIRCUIT - Conventional bias circuits exhibit a number of limitations, including the time required to power-up a bias circuit following a low-power state. Large current surges in the supply network induce ringing, further complicating a power-up process. Example embodiments reduce power-up time and minimize current surges in the supply by selectively charging and discharging capacitance to the circuit during power-up and power-down of the bias circuit. | 07-05-2012 |
20120206280 | Multiple Word Data Bus Inversion - A data encoding scheme for transmission of data from one circuit to another circuit considers the Hamming Weight of combined multiple words to determine whether to invert or not invert an individual word to be transmitted. The multi-word data encoding scheme performs DBI encoding with data inversion conducted based on the total HW in the combined multiple words. The decision to invert or not invert each of the multiple words is made based on the sum of the individual Hamming Weights of each of the words. Such encoding has the advantage that SSO noise is dramatically reduced when the encoded data has a large number of words transmitted from one circuit to another circuit over a wide parallel bus. | 08-16-2012 |
20130009686 | Methods and Apparatus for Transmission of Data - A system includes a transmitter circuit and a receiver circuit that are coupled together through transmission lines. The transmitter circuit generates an early timing signal, a nominal timing signal, and a late timing signal. A multiplexer circuit selects between the early and the late timing signals based on a data signal to generate an encoded output signal that encodes the data signal. The nominal timing signal and the encoded output signal are transmitted through the transmission lines to the receiver circuit. The receiver circuit samples the encoded output signal in response to the nominal timing signal to generate even and odd sampled data signals. Complementary timing signals can be transmitted through transmission lines on opposite sides of the encoded output signal to provide crosstalk cancellation. | 01-10-2013 |
20130249612 | METHOD AND APPARATUS FOR SOURCE-SYNCHRONOUS SIGNALING - A low-power, high-performance source-synchronous chip interface which provides rapid turn-on and facilitates high signaling rates between a transmitter and a receiver located on different chips is described in various embodiments. Some embodiments of the chip interface include, among others: a segmented “fast turn-on” bias circuit to reduce power supply ringing during the rapid power-on process; current mode logic clock buffers in a clock path of the chip interface to further reduce the effect of power supply ringing; a multiplying injection-locked oscillator (MILO) clock generator to generate higher frequency clock signals from a reference clock; a digitally controlled delay line which can be inserted in the clock path to mitigate deterministic jitter caused by the MILO clock generator; and circuits for periodically re-evaluating whether it is safe to retime transmit data signals in the reference clock domain directly with the faster clock signals. | 09-26-2013 |
20130346822 | ERROR DETECTION AND OFFSET CANCELLATION DURING MULTI-WIRE COMMUNICATION - Embodiments of a circuit are described. In this circuit, a receive circuit includes M input nodes that receive a set of M symbols on M links during a time interval, where the set of M symbols are associated with a codeword. Moreover, the receive circuit includes a decoder, coupled to the M input nodes, that determines the codeword in a code space based on the set of M symbols and that decodes the codeword to a corresponding set of N decoded symbols. Additionally, the receive circuit may include a detector that detects an imbalance in a number of instances of a first value in the set of M symbols and a number of instances of a second value in the set of M symbols, and, if an imbalance is detected, that asserts an error condition. | 12-26-2013 |
20140210545 | ON-CHIP REGULATOR WITH VARIABLE LOAD COMPENSATION - An integrated circuit includes a voltage regulator to supply a regulated voltage and a data output that couples to an unterminated transmission line. The circuit draws a variable amount of power from the voltage regulator according to the data. The voltage regulator includes a first current generation circuit to provide a data transition-dependent current. | 07-31-2014 |
20140376364 | TEMPORAL REDUNDANCY - A circuit is provided to facilitate temporal redundancy for inter-chip communication. When an inter-chip communication channel fails, data bits associated with the faulty channel are steered to a non-faulty channel and transmitted via the non-faulty channel together with data bits associated with the non-faulty channel at an increased data rate. | 12-25-2014 |