Optical Transceiver IC Decision-Level Hold During Sleep Mode
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
In optical transceivers, the analog approach to determining decision levels fails when the input signal is not continuous, leading to errors due to leakage current, which is problematic in power-managed environments like PC/Server systems where quick recovery from sleep states is necessary.
Innovation Solution
A digital loop is introduced to determine the decision level, using a comparator and counter to maintain the decision level during sleep modes and adjust loop stability dynamically, combined with a signal detect circuit to manage power consumption.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Use of energy by moving object
If the transceiver enters sleep state to save power, then power consumption is reduced, but the decision level accuracy deteriorates due to leakage current
Solution Approach 1:
The system performs preliminary action by capturing and storing the decision level value in a register before entering sleep mode. This stored value is then used during the sleep period to maintain accurate decision-making capability without requiring continuous analog circuit operation, thus preserving accuracy while saving power.
Solution Approach 2:
The patent replaces the continuous analog RC filter circuit with a digital sampling and storage mechanism. Instead of maintaining a continuous analog voltage level that is susceptible to leakage, the system samples the decision level digitally and holds it in a register, substituting analog persistence with digital memory to eliminate leakage-related drift.
2Ease of operation
If the RC filter circuit is used to determine decision level, then the decision level can be derived from continuous data stream, but the decision level droops over time due to capacitor leakage current
Solution Approach 1:
The patent substitutes the analog RC filter circuit with a digital sampling and holding system. The decision level is captured digitally using a sampler circuit and stored in a register, replacing the continuous analog filtering process with discrete digital sampling. This eliminates the capacitor leakage issue inherent in RC circuits while maintaining the ability to derive decision levels from data streams.
Solution Approach 2:
The system creates a digital copy of the decision level value by sampling the analog decision level signal and storing it in a digital register. This digital copy preserves the decision level information without being subject to the physical degradation mechanisms (leakage current) that affect the original analog RC filter circuit over time.
3Measurement precision
If continuous data stream is required for decision level determination, then accurate decision level can be maintained, but power consumption increases preventing sleep states
Solution Approach 1:
The system performs preliminary sampling of the decision level before entering sleep mode, capturing the necessary information in advance. This allows the transceiver to enter low-power sleep states while retaining accurate decision level data from the preliminary sampling action, eliminating the need for continuous data streaming during sleep periods.
Solution Approach 2:
Instead of continuous operation, the system employs periodic sampling of the decision level at intervals. The sampler circuit captures decision level values periodically, and these sampled values are held in registers during sleep periods. This periodic action maintains accuracy while enabling power savings during intervals between samples.
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
This digital approach ensures accurate decision levels upon wake-up and reduces power consumption by maintaining circuit states during sleep modes, improving power management in optical transceivers.
Implementation Method 1
a photodiode may generate a current in response an optical signal received from an optical transmission medium
Data Source
AI summary
A power management arrangement for low power optical transceiver such as those that may be integrated into a personal computer or server may periodically put itself into a power conservation or sleep mode which assures the transceiver is available upon wake-up.