Latch Circuit Feedback Multiplexer for Extra Inputs Without Speed Loss
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Solution Overview
Problem
Existing latch circuits face performance degradation when additional inputs are required, as multiplexers on the forward data path affect functional mode performance.
Innovation Solution
A latch circuit design that incorporates a multiplexer within the feedback loop, allowing selection between forming a feedback loop or a secondary data transmission path, thereby providing additional inputs without impacting the forward data path performance.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If a multiplexer is added to provide an additional input for processing both functional data and scan data, then the latch can handle multiple data types, but the performance of the latch in functional mode is degraded
Solution Approach 1:
The patent divides the data path into two separate paths: a forward data path for functional data and a feedback loop path for scan data. The multiplexer is placed only in the feedback loop path, allowing it to select between scan data and feedback signal without affecting the forward data path. This segmentation isolates the multiplexer's impact to only the scan path, preserving functional mode performance.
Solution Approach 2:
The feedback loop acts as an intermediary path that handles scan data transmission. By placing the multiplexer within this intermediary feedback loop rather than directly in the forward data path, the patent allows scan data to be routed through the feedback loop while keeping the primary functional data path clean and high-performance.
2Adaptability or versatility
If a multiplexer is placed on the forward data path to select between scan input and data input, then additional input functionality is provided, but the performance of the forward data path is affected
Solution Approach 1:
The patent extracts the multiplexer from the forward data path and relocates it to the feedback loop path. This extraction removes the performance-degrading element from the critical forward data path while maintaining the multiplexer's essential function of selecting between different data sources in the scan path.
Solution Approach 2:
Instead of placing the multiplexer in the conventional forward data path position, the patent inverts the approach by placing it in the feedback loop path. This inverted placement achieves the same input selection functionality but without the performance penalty, as the feedback loop is not performance-critical.
Data Source
AI summary
A latch circuit for retaining and transmitting an input data value is disclosed, along with a memory, and a method for retaining and transmitting data. The latch circuit includes a primary input for receiving a data value, an output for outputting the data value, a data transmission path including a transmitting device for transmitting the data value from the primary input to the output, a feedback loop for retaining the data value, the feedback loop including the transmitting device and a further device. The further device is configured to turn on in response to assertion of an activating signal and to turn off in response to no assertion of the activating signal. The feedback loop not retaining data when the further device is turned off, and the feedback loop further including a multiplexer, and the multiplexer is configured to connect either the data transmitting device to the further device and form the feedback loop or to connect a secondary input to the further device and form a secondary data transmission path from the secondary input through the further device and the transmitting device to the output.