Reception Device Offset Adjustment Circuit
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Solution Overview
Problem
Traditional reception devices for high-speed differential transmission face challenges in adjusting offset without increasing circuit area and power consumption, and the process can introduce noise due to short-circuiting the differential signal line.
Innovation Solution
A reception device with a signal input unit that adjusts offset by generating logical value data and includes a request output unit to request offset adjustment signals from the transmission device, allowing for offset adjustment without additional circuit area or power consumption, using a signal line with a resistor and switch for request signal transmission.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of operation
If a switch is provided to short-circuit the differential signal line at the input end of the reception device for offset adjustment, then offset adjustment is enabled, but the load capacity at the input end increases which adversely affects high-speed differential transmission
Solution Approach 1:
The patent extracts the offset adjustment function from the main signal path by using a separate single-ended signal line instead of short-circuiting the differential signal line. This removes the harmful short-circuit operation that increased input load capacity while preserving the offset adjustment capability through a dedicated control path.
Solution Approach 2:
The patent introduces a mediator approach by using a separate control signal line (not part of the differential pair) to transmit adjustment commands. This intermediary path allows offset adjustment without directly interfering with the high-speed differential signal transmission, avoiding the load capacity increase problem.
2Ease of operation
If a circuit for detecting the offset is provided to adjust the offset, then offset adjustment is enabled, but the circuit area and power consumption of the reception device become large
Solution Approach 1:
The patent makes the existing differential signal line serve multiple functions: it transmits both the high-speed data signals and carries the offset adjustment information through the sampling of adjustment signals. This multi-functionality eliminates the need for separate detection circuits, reducing circuit area and power consumption while maintaining offset adjustment capability.
Solution Approach 2:
The reception device uses its own existing signal input unit and sampling circuitry to detect offset by processing the adjustment signals transmitted through the differential line. The same circuit that processes data signals also performs offset detection, making the system self-sufficient without requiring additional dedicated detection circuits.
3Measurement precision
If the differential signal line is short-circuited by closing the switch at the input end of the reception device for offset detection, then offset can be detected, but the transmitted signal may become noise for the reception device
Solution Approach 1:
The patent extracts the offset detection process from the main differential signal path and performs it using a separate control mechanism. By not short-circuiting the differential line during adjustment, the harmful noise generation is eliminated while offset detection accuracy is maintained through sampling of dedicated adjustment signals.
Solution Approach 2:
The patent performs offset adjustment during a predetermined period when no high-speed data transmission occurs. Adjustment signals are transmitted and processed in advance before normal operation begins, allowing accurate offset detection without the differential line being in a harmful short-circuited state during active transmission.
Data Source
AI summary
The invention relates to a reception device, etc., applied to a transmission/reception system capable of performing high-speed transmission, having a structure to enable to adjust an offset without increasing a circuit area and power consumption. The reception device includes a signal input unit including an offset adjusting circuit, and an adjustment unit. When a pair of adjusting signals of which a voltage between signals is fixed to zero V is outputted from a transmission device to the reception device connected to each other via a differential signal line including at least a pair of signal lines, the signal input unit that has received the pair of adjusting signals outputs logical value data corresponding to the voltage between signals. The adjustment unit determines adjustment value data to adjust the offset of a threshold to obtain the logical value data based on the logical value data inputted in a certain period.