Master-Slave Latch Skewed Clocking for Timing Margin Control
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Solution Overview
Problem
Master-slave latches in semiconductor devices face timing margin issues due to the use of a common clock, which can be resolved by injecting additional time delay using buffers, but this approach is not optimal for ensuring accurate and stable output signals.
Innovation Solution
A skewed clock circuit generates individual clock signals for the master and slave latches, allowing for independent control of delays and reducing the overall setup time by altering the timing of clock edges, thereby improving the accuracy and stability of output signals.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Device complexity
If a common clock is used for master and slave latches, then the circuit structure is simple, but timing margin issues occur and setup time is insufficient
Solution Approach 1:
The common clock signal is segmented into two separate clock signals: a first clock signal for the master latch and a second clock signal for the slave latch. This segmentation allows independent timing control of each latch, resolving the timing margin issues that arise from using a single common clock while maintaining relatively simple circuit architecture.
Solution Approach 2:
The patent introduces dynamic timing adjustment by allowing the first and second clock signals to have different phases and timing characteristics. The master latch clock and slave latch clock can be independently adjusted to optimize setup and hold times, making the system dynamically adaptable to different timing requirements rather than being static with a fixed common clock period.
2Reliability
If buffers are added to inject time delay, then timing margin issues are resolved, but device complexity increases
Solution Approach 1:
Instead of adding buffers to a common clock, the patent segments the clock distribution into separate paths for master and slave latches. This segmentation provides timing adjustment capability without requiring additional buffer components, thus resolving timing margin issues while avoiding increased device complexity.
Solution Approach 2:
The patent employs dynamic phase and timing adjustment of the segmented clock signals to achieve the desired timing margins. This dynamic approach allows precise timing control without the need for static buffer-based delay injection, maintaining circuit simplicity while ensuring reliable timing.
3Reliability
If skewed clock signals are used for master and slave latches, then setup time is enhanced and output stability is improved, but clock circuit complexity increases
Solution Approach 1:
The clock circuit is segmented to generate separate first and second clock signals with different timing characteristics for the master and slave latches. This segmentation enables skewed clock operation that improves output stability while keeping the clock circuit structure manageable through systematic signal distribution.
Solution Approach 2:
The clock circuit incorporates dynamic timing control to generate skewed clock signals with optimized phases and durations for each latch. This dynamic skewing enhances setup time and output stability without requiring overly complex clock generation circuitry, as the skew is achieved through controlled signal distribution rather than complex synthesis.
Data Source
AI summary
Circuits, systems, and methods are described herein for generating master clock signals and slave clock signals for controlling a flip-flop having a master latch and a slave latch. A circuit includes a master latch configured to latch an input data signal and to output a data latch signal based on a master clock signal. The circuit also includes a slave latch coupled to the master latch and configured to generate an output data signal based on a slave latch clock signal and the data latch signal. Additionally, the circuit includes a skewed clock circuit coupled to the master latch and the slave latch. The skewed clock circuit is configured to receive a clock signal and generate the master clock signal and the slave clock signal based on the clock signal. The master clock signal and the slave clock signal are independent clock signals whose timing is skewed relative to one another by the skewed clock circuit.