LVDS Receiver Distortion Correction With Selective Diode Loads
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Solution Overview
Problem
Low-voltage differential signaling (LVDS) receivers face challenges in reducing power consumption and addressing signal distortion, particularly duty cycle distortions, which can lead to glitches in differential output signals due to voltage and current couplings.
Innovation Solution
The proposed LVDS receiver design includes a differential pair of transistors, current mirrors, and load transistors with selective diode connections, along with a signal distortion correction circuit that uses non-overlapping clock generators and logic gates to detect and adjust for distortions, ensuring proper signal transitions and reduced power consumption.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Strength
If the LVDS receiver amplifies the differential signal to generate full-rail output, then the output signal level is improved, but power consumption increases substantially
Solution Approach 1:
The patent implements dynamic control of the differential pair transistors through selective diode connection of load transistors. The receiver operates in two modes: linear amplification mode for signal restoration and saturated switching mode for power reduction. This dynamic operation allows the system to achieve full-rail output signals while consuming substantially less power by spending most time in the low-power saturated mode and only briefly in linear mode during transitions.
2Use of energy by moving object
If the LVDS receiver operates with low voltage swing, then power consumption is reduced, but signal distortion occurs due to voltage and current couplings
Solution Approach 1:
The patent applies preliminary action by pre-charging and pre-discharging the load transistors before the differential pair needs to switch states. The selective diode connection mechanism prepares the output nodes in advance, ensuring that when the differential pair transitions, the full-rail output is achieved without distortion. This preliminary preparation eliminates the harmful effects of voltage and current couplings that would otherwise cause signal distortion.
3Use of energy by moving object
If the LVDS receiver uses selective diode connection of load transistors, then power consumption is reduced, but circuit complexity increases
Solution Approach 1:
The patent merges multiple functions into the load transistors and their control circuitry. The load transistors simultaneously serve as amplification elements, power control elements, and output buffer elements. The selective diode connection mechanism combines bias control, power management, and signal restoration functions into a unified circuit structure, reducing overall complexity despite the dynamic operation mode.
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 design effectively amplifies differential input voltages to full-rail output signals while minimizing power consumption and robustly correcting duty cycle distortions, ensuring reliable signal transmission.
Implementation Method 1
a differential pair of transistors configured to amplify a differential input voltage into a first differential voltage
Implementation Method 2
a first current mirror configured to produce a first current responsive to a drain voltage of the first transistor; a second current mirror configured to produce a second current responsive to a drain voltage of the second transistor
Data Source
AI summary
A low-voltage differential signaling receiver is provided that amplifies a differential input voltage to produce a differential output voltage. A signal distortion circuit that detects a distortion in a differential output voltage to assert a signal detection signal that adjusts a gate voltage of a pair of load transistors to reduce the distortion. The load transistors are selectively diode connected to reduce power consumption.