Apple Inc.

Advanced Micro Devices Corporation

Charles L Wang

Yi-Hsiu E Chen

Yikun Chang

Pranavi Sunkara

Sanjeev K Maheshwari

Dennis M Fischette, Jr

Samed Maltabas

Khaled M Alashmouny

Wei-Ming Lee

Karen Tucker

Randall Shaw

Chih-Yuan Chen

Yudong Zhang

Yu-Yau Guo

The present disclosure describes embodiments of driver circuit. The driver circuit includes a first impedance element electrically coupled to a first inverter circuit and a second impedance element electrically coupled to the first impedance element and a second inverter circuit. For a first encoding using the driver circuit, the first inverter circuit and the second inverter circuit are controlled such that a first current flows through the first and second impedance elements, the first current having a first value and a first direction. For a second encoding using the driver circuit, the first inverter circuit and the second inverter circuit are controlled such that a second current flows through the first and second impedance elements, the second current having a second value and a second direction. The first value is substantially the same as the second value and the first direction is opposite to the second direction.

Coding for pulse amplitude modulation with an odd number of output levels

An apparatus for performing a fast common mode recharge is disclosed. The apparatus includes a transmitter circuit configured to transmit a differential signal on a communication bus that includes a true signal line and a complement signal line and a measurement circuit configured to measure respective voltage levels of the true signal line and the complement signal line. The apparatus further includes a control circuit configured to, in response to exiting a sleep mode, select one of a plurality of operation modes using the respective voltage levels of the true signal line and the complement signal line. The transmitter circuit is further configured to adjust the respective voltage levels of the true signal line and the complement signal line based on a selected operation mode of the plurality of operation modes.

Fast common mode charging

A driver circuit for a serial communication bus employs multiple switch circuits to generate different voltage levels on a set of signal lines included in the serial communication bus. The different voltage levels correspond to different values for a set of bits to be transmitted via the serial communication bus. The driver circuit also employs a shunt circuit that couples at least two of the signals together in response to the set of bits matching a particular data pattern.

Serial communication link driver circuit with switchable shunt circuit

An Integrated Circuit includes a target circuit, first and second logic chains, a feedback path and calibration circuitry. The target circuit includes first and second inputs. The first and second logic chains propagate a signal from a common input point to the first and second inputs of the target circuit, respectively. The feedback path receives the signal from the first or second input and feeds the signal back to the common input point. The calibration circuitry is configured to connect the first input to the feedback path thereby forming a first closed-loop oscillator circuit, and measure a first oscillation frequency of the first closed-loop oscillator circuit, connect the second input to the feedback path, thereby forming a second closed-loop oscillator circuit, and measure a second oscillation frequency of the second closed-loop oscillator circuit, and verify a timing constraint responsively to the first and second oscillating frequencies.

Method and apparatus for in-situ on-chip timing

A system and method for efficient on-chip monitoring of clock signals post-silicon. An electronic circuit includes a post-silicon and on-die signal monitor and a first signal generator that sends a first signal with a first signal period to the signal monitor. The signal monitor selects a first sampling signal with a first sampling period such that a ratio of the first sampling period to the first signal period is greater than one and is a non-integer. The signal monitor selects a reference voltage level for indicating when the first signal is asserted. When the first sampling period has elapsed, the signal monitor samples the first signal to generate a voltage level, and upon completing sampling, determines a duty cycle of the generated voltage levels, which indicates a duty cycle of the first signal. Using a similar approach, the signal monitor is also capable of determining skew between two signals.

Duty cycle and skew measurement and correction for differential and single-ended clock signals

Apparatus and methods are provided for generating output signals representative of bits of serial data. A transmitter includes driver circuitry configured to generate an output signal at an output node and an allocation control module coupled to the driver circuitry. The driver circuitry includes a plurality of driver legs configured to generate the output signal based on a plurality of data bits. The allocation control module is configured to allocate a respective subset of the plurality of driver legs to a respective data bit of a plurality of data bits, wherein the each subset generates a component of the output signal that is influenced by its respective data bit.

Adjustable finite impulse response transmitter

Apparatus and methods are provided for generating output signals representative of bits of serial data. A transmitter comprises a plurality of delay elements, driver circuitry, and bypass logic coupled between the plurality of delay elements and the driver circuitry. The plurality of delay elements delay serialized data, resulting in delayed serialized data, and the driver circuitry generates an output signal representative of a first bit of the delayed serialized data. The bypass logic is configured to selectively bypass one or more delay elements of the plurality of delay elements to provide the first bit of the delayed serialized data to the driver circuitry.

Growing community of inventors

Los Altos, CA, United States of America

Charles L Wang