Advanced Micro Devices Corporation

Ati Technologies Ulc

Karthik Gopalakrishnan

Pradeep Jayaraman

Aaron D Willey

Aaron John Nygren

Tsun Ho Liu

Ramon Mangaser

Andy Huei Chu

Michael John Litt

Tom Moiannou

Achal Kathuria

Andrew Egli

A memory includes a read clock circuit and a mode register. The read clock circuit has an output for providing a hybrid read clock signal in response to a clock signal and a read clock mode signal. The mode register provides the read clock mode signal in response to a read clock mode, wherein the read clock circuit provides the hybrid read clock signal as a free-running clock signal that toggles continuously when the read clock mode is a first mode, and as a strobe signal that is active only in response to the memory receiving a read command when the read clock mode is a second mode.

Read clock start and stop for synchronous memories

A memory includes a read clock state machine and a read clock driver circuit. The read clock state machine has a first input for receiving a read command signal, a second input for receiving a read clock mode signal, and an output for providing a drive enable signal. The read clock driver circuit has an output for providing a read clock signal in response to a clock signal when the drive enable signal is active. When the read clock mode signal indicates a read-only mode, the read clock state machine starts toggling the read clock signal during a read preamble period before a data transmission of a first read command, and continues toggling the read clock signal for at least a read postamble period following the data transmission of the first read command.

A voltage regulator includes an input power supply node, an output regulated power supply node, a flipped voltage follower circuit, and a compensation capacitor. The flipped voltage follower circuit includes an output transistor configured as a common-source amplifier circuit. A source terminal of the output transistor is coupled to the input power supply node and a drain terminal of the output transistor is coupled to the output regulated power supply node. The flipped voltage follower circuit includes a folded cascode feedback circuit. The folded cascode feedback circuit includes a folding node. The folded cascode feedback circuit is configured to receive an output regulated voltage on the output regulated power supply node and to provide a feedback signal to a gate terminal of the output transistor. The compensation capacitor is coupled to the output regulated power supply node and the folding node.

Flipped voltage follower low-dropout regulator with frequency compensation

A data transmission system includes a first integrated circuit. The first integrated circuit includes a first mixing terminal coupled to a first power supply voltage terminal at a point internal to the first integrated circuit, a first return terminal, a first resistor having a first terminal coupled to the first mixing terminal, and a second terminal for providing a first mixed voltage, and a second resistor having a first terminal coupled to the second terminal of the first resistor, and a second terminal coupled to the first return terminal.

Efficient and low power reference voltage mixing

A memory controller monitors memory command selected for dispatch to the memory and sends commands controlling a read clock state. A memory includes a read clock circuit and a mode register. The read clock circuit has an output for providing a hybrid read clock signal in response to a clock signal and a read clock mode signal. The read clock circuit provides the hybrid read clock signal as a free-running clock signal that toggles continuously, and as a strobe signal that is active only in response to the memory receiving a read command.

A receiver is trained for receiving a signal over a data bus. A volatile memory is commanded over the data bus to place a selected pulse-amplitude modulation (PAM) driver in a mode with a designated steady output level. At a receiver circuit coupled to the selected PAM driver, a respective reference voltage associated with the designated steady output level is swept through a range of voltages and the respective reference voltage is compared to a voltage received from the PAM driver to determine a respective voltage level received from the PAM driver.

Error pin training with graphics DDR memory

An integrated circuit includes a first terminal for receiving a data signal, a second terminal for receiving an external reference voltage, a receiver, and a reference voltage generation circuit. The receiver is powered by a power supply voltage with respect to ground and has a first input coupled to the first terminal, a second input for receiving a shared reference voltage, and an output for providing a data input signal. The reference voltage generation circuit is coupled to the second terminal and receives the power supply voltage. The reference voltage generation circuit is operable to form the shared reference voltage by mixing noise from the power supply voltage and noise from the second terminal.

Noise mitigation in single-ended links

A method for receiving a multi-level error signal having more than two logic levels includes oversampling the multi-level error signal to provide sampled symbols, wherein a first level of the multi-level error signal indicates no error, and second and third levels of the multi-level error signal indicate first and second error conditions, respectively. The sampled signals are de-serialized to provide sets of symbols. A start of a symbol period is determined in response to detecting that a given sample is different from a prior sample, and the prior sample indicates no error. The sets of symbols are filtered to provide corresponding output symbols based on the start.

Multi-level signal reception

A driver circuit includes a feed-forward equalization (FFE) circuit. The FFE circuit receives a plurality of pulse-amplitude modulation (PAM) symbol values to be transmitted at one of multiple PAM levels. The FFE circuit includes a first partial lookup table, one or more additional partial lookup tables, and an adder circuit. The first partial lookup table contains partial finite impulse-response (FIR) values and indexed based on a current PAM symbol value, a precursor PAM symbol value, and a postcursor PAM symbol value. The one or more additional partial lookup tables each contain partial FIR values and indexed based on a respective additional one or more of the PAM symbol values. The adder circuit adds results of lookups from the first partial lookup table and the additional partial lookup tables to produce an output value.

Lookup table optimization for high speed transmit feed-forward equalization link

A data processor, system, method, integrated circuit are provided which update timing values for accessing a memory to compensate for voltage and temperature (VT) drift during operation. The method includes performing a link retraining sequence for a plurality of DQ lanes of the memory bus and determining a first phase offset based on the link retraining. The method includes calculating a second offset based on the first offset, applying the second offset to a plurality of command CA lanes of the memory bus.

Feed forward training of memory interfaces

A read clock circuit selectively provides a read clock signal from a memory to a memory controller over a memory bus. A pulse-amplitude modulation (PAM) driver including an input and an output capable of driving at least three levels indicating respective digital values. A digital control circuit is coupled to the PAM driver and operable to cause the PAM driver to provide a preamble signal before the read clock signal, the preamble signal including an initial toggling state in which the PAM driver toggles between two selected levels at a first rate, and a final toggling state in which the PAM driver toggles between two selected levels at a second rate higher than the first rate, with a length of the initial toggling state and a length of the final toggling state are based on values in a mode register.

Read clock toggle at configurable PAM levels

The disclosed computer-implemented method includes providing, by a reference clock circuit, a clock signal for a clock-triggered element triggered by the clock signal and modulating, by a frequency modulation circuit, a frequency of the clock signal. The method also includes inserting, by a phase compensation circuit, a phase compensation offset to the modulated clock signal in a manner that compensates for a phase error produced by modulating the frequency of the clock signal. Various other methods, systems, and computer-readable media are also disclosed.

Compensation for clock frequency modulation

A clocking circuit is provided using a master delay-locked loop (DLL) and a slave DLL. A master DLL code indicates a delay adjustment made at a master DLL. A delay of a slave DLL is adjusted based on the master DLL code. A replica phase detector at the slave DLL is temporarily enabled during an interface idle period. A slave DLL code is determined, and a configuration value is determined based on the slave DLL code to the master DLL code. The replica phase detector is then disabled.

Delay-locked loop offset calibration and correction

A memory controller monitors memory command selected for dispatch to the memory and sends commands controlling a read clock state. A memory includes a read clock circuit and a mode register. The read clock circuit has an output for providing a hybrid read clock signal in response to a clock signal and a read clock mode signal. The mode register provides the read clock mode signal in response to a read clock mode, wherein the read clock circuit provides the hybrid read clock signal as a free-running clock signal that toggles continuously when the read clock mode is a first mode, and as a strobe signal that is active only in response to the memory receiving a read command when the read clock mode is a second mode.

A memory includes a link training circuit with a pseudo-random bit sequence (PRBS) generator and a burst error detection counter. The burst error detection counter including a comparator, a first input coupled to the data input, a second input coupled to the PRBS generator, and a counter operable to increase an error count value by one responsive to detecting any number of errors greater than zero in a sequence of symbols including a predetermined number of symbols.

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Cupertino, CA, United States of America

Karthik Gopalakrishnan