Differential Input Latch Control to Block DC Current Before Preambles
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Solution Overview
Problem
Existing semiconductor devices face challenges in preventing DC current from flowing between differential signals, which affects signal integrity and power consumption, especially during unknown intervals before preambles of differential signals are received.
Innovation Solution
A semiconductor device with a buffer circuit that includes a first and second input unit for differential amplification, a cross-coupled inverter latch, and a latch controller to compare phases of differential signals and selectively switch the latch operation, preventing DC current flow by disabling the latch when signal phases are identical and enabling it when phases are different.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a latch is continuously enabled to prevent duty variation of differential signals, then signal integrity is improved, but DC current flows between differential signals during unknown intervals before preambles are received
Solution Approach 1:
The latch operation is made dynamic by selectively enabling and disabling it based on the reception state of differential signals. The latch controller monitors whether preambles have been received and adjusts the latch operation accordingly: enabled during normal operation to maintain signal integrity, and disabled during unknown intervals to prevent DC current flow and reduce power consumption.
Solution Approach 2:
The operational state of the latch is changed based on the reception status of differential signals. By detecting whether preambles are received, the system changes the latch parameter from enabled to disabled state, thereby controlling the flow of DC current while maintaining signal integrity when needed.
2Stability of the object's composition
If a latch is continuously enabled to align duty cycles of differential signals, then duty cycle alignment is achieved, but DC current flows during unknown intervals before preambles are received
Solution Approach 1:
The latch operation is dynamically controlled based on the reception state of differential signals. During unknown intervals before preambles are received, the latch is disabled to prevent DC current flow. Once preambles are detected, the latch is enabled to align duty cycles, thus achieving stable duty cycle alignment only when necessary.
Solution Approach 2:
The operational parameter of the latch is changed based on signal reception status. The latch controller detects whether preambles are received and accordingly changes the latch state between enabled and disabled, controlling duty cycle alignment and preventing DC current flow at different operational stages.
3Loss of energy
If the latch is disabled during unknown intervals to prevent DC current flow, then power consumption is reduced, but duty cycle alignment cannot be maintained
Solution Approach 1:
The latch operation is performed periodically based on the reception of preambles. During unknown intervals, the latch remains disabled to save power. Once preambles are received, the latch is enabled to perform duty cycle alignment. This periodic enabling and disabling based on signal reception events resolves the contradiction between power saving and duty cycle alignment.
Solution Approach 2:
The system performs preliminary detection of preambles before enabling the latch for duty cycle alignment. This preliminary action allows the system to determine when it is safe to enable the latch, ensuring that duty cycle alignment is maintained only when differential signals are properly received, thereby avoiding unnecessary power consumption.
Data Source
AI summary
Provided is a semiconductor device to prevent DC current from flowing between differential input signals. The semiconductor device includes a first input unit configured to buffer a first signal of differential input signals, a second input configured to buffer a second signal of the differential input signals, and a latch coupled between a first repeating node of the first input unit and a second repeating node of the second input unit to prevent duty variation of the first and second signals. The semiconductor device further includes a latch controller configured to selectively switch the operation of the latch based on states of the first and second signals appearing at the first and second repeating nodes during a time interval before preambles of the differential input signals are received.