Receiver Common-Mode Calibration for Faster Latch Sensing
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Solution Overview
Problem
High-speed transmission applications require faster latch speeds in sensing circuits, but these are affected by manufacturing processes and temperature, leading to variability in signal strength and increased code error rates due to attenuated signal strength during transmission.
Innovation Solution
A receiver with a self-calibration circuit and phase comparator that sets different common-mode levels during a testing period to determine a calibrated level, then sets all common-mode levels equal to this calibrated level during normal operation to optimize latch speeds.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Speed
If common-mode levels at input terminals of sensing circuits are set differently to optimize latch speeds, then latch speed varies across circuits, but manufacturing process and temperature variations cause variability in signal strength and increase code error rates
Solution Approach 1:
The patent applies parameter changes by adjusting the common-mode voltage level at the input terminals of sensing circuits. During a calibration period, different common-mode levels are applied to different sensing circuits to determine optimal settings. The determined optimal common-mode level is then applied uniformly to all sensing circuits during normal operation, optimizing latch speeds while maintaining reliability across manufacturing and temperature variations.
2Reliability
If equalizer circuits are added to compensate for signal loss, then signal strength is improved, but device complexity increases
Solution Approach 1:
The patent implements a self-calibration mechanism where the system automatically determines and applies optimal common-mode levels to sensing circuits without requiring external intervention or complex manual adjustment. The calibration process is performed autonomously during an initial period, and the optimized settings are maintained during normal operation, reducing the need for additional complex control circuits while maintaining signal integrity.
Data Source
AI summary
A receiver and a common-mode voltage calibration method thereof are provided. The receiver includes sensing circuits, a phase comparator, and a self-calibration circuit. The phase comparator compares phase relationships of the latch results at the output terminals of the sensing circuits during a testing period to produce a phase comparison result. During the testing period, the self-calibration circuit provides the same differential signal to the input terminals of these sensing circuits, and sets common-mode levels at the input terminals of these sensing circuits to be different from one another. The self-calibration circuit determines a calibrated common-mode level based on the phase comparison result. The self-calibration circuit sets the common-mode levels at the input terminals of these sensing circuits to be equal to the calibrated common-mode level during a normal operation period.