Cross-Coupled Latch Enable Scheme for Parasitic Coupling Isolation
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Solution Overview
Problem
Conventional latches in digital electronics face challenges in efficiently storing data due to parasitic capacitive coupling, which can lead to signal interference and instability, especially when sharing components with other latches.
Innovation Solution
The design incorporates cross-coupled invertors and a specific configuration of transistors, including pMOS and nMOS transistors, to control the latch's operation, with parasitic capacitors being interrupted by enable signals, preventing coupling between input terminals and allowing component sharing without signal interference.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If latches share components with other latches, then device complexity is reduced and productivity is improved, but parasitic capacitive coupling causes signal interference and instability
Solution Approach 1:
The patent introduces an enable signal as an intermediary control mechanism that manages the coupling between latches. The enable signal acts as a mediator that selectively activates or deactivates the connection between shared components and input terminals, preventing parasitic capacitive coupling from causing signal interference while allowing component sharing to improve productivity.
Solution Approach 2:
The patent applies preliminary anti-action by using the enable signal to preemptively prevent parasitic capacitive coupling before it can cause signal interference. The enable signal is configured to block coupling paths in advance, eliminating the harmful effect of parasitic capacitance while maintaining the benefits of shared components.
2Device complexity
If conventional latch configurations are used, then device complexity is low, but parasitic capacitive coupling leads to signal interference and instability
Solution Approach 1:
The enable signal serves as an intermediary that controls the coupling between latches without significantly increasing device complexity. By introducing this single control signal, the patent prevents parasitic capacitive coupling from causing harmful signal interference while maintaining a relatively simple latch structure.
Solution Approach 2:
The patent changes the operational parameter of the latch by introducing an enable signal that dynamically controls the coupling state. This parameter change allows the latch to switch between coupled and uncoupled states, preventing parasitic signal interference while maintaining structural simplicity.
Data Source
AI summary
A circuit includes cross coupled invertors including a first invertor and a second inventor. The first invertor and the second invertor are cross coupled at a first data node and a second data node. An input unit is coupled between the cross-coupled invertors and a power node. The input unit controls the cross-coupled invertors in response to a first input signal received at a first input terminal of the input unit and a second input signal received at a second input terminal of the input unit. A first transistor is connected between the power node and a supply node. The first transistor connects the power node to the supply node in response to an enable signal changing to a first value. A second transistor is connected between the power node and ground. The second transistor connects the power node to the ground in response to the enable signal changing to a second value.