Master-Slave Flip-Flop Clock Sharing Without Logic Contention
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Solution Overview
Problem
Existing master-slave flip-flops in digital logic circuits consume significant power, and previous methods to reduce this consumption often increase circuit area, lead to performance penalties, or result in unstable operation due to logic contention when sharing clock switches.
Innovation Solution
The design shares clock switches between specific three-state stages in a master-slave flip-flop, using complementary semiconductor devices with additional pairs to prevent logic contention, reducing the number of clock switches and power consumption while maintaining performance and avoiding logic conflicts.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Loss of energy
If the number of clock switches is reduced to lower power consumption, then power consumption decreases, but logic contention occurs leading to unstable operation
Solution Approach 1:
The flip-flop circuit is divided into four distinct three-state stages (first, second, third, and fourth stages), each with specific enablement conditions. The master latch comprises first and second stages, while the slave latch comprises third and fourth stages. This segmentation allows each stage to be independently controlled, preventing logic contention while reducing the number of clock switches needed compared to a conventional design.
Solution Approach 2:
Each three-state stage has differentiated enablement characteristics - the first and third stages are enabled by one phase of the clock signal, while the second and fourth stages are enabled by the opposite phase. This local quality differentiation ensures that adjacent stages never activate simultaneously, eliminating logic contention and maintaining operational stability with fewer clock switches.
2Area of stationary object
If clock switches are shared among multiple three-state stages, then circuit area and power consumption are reduced, but logic contention and unstable operation occur
Solution Approach 1:
The circuit is segmented into four distinct three-state stages with clearly defined boundaries and control mechanisms. Each stage can share clock switches with non-adjacent stages (e.g., first stage shares with third stage, second stage shares with fourth stage) without causing contention, as the enablement phases are staggered to prevent simultaneous activation of sharing resources.
Solution Approach 2:
The patent introduces additional pairs of complementary semiconductor devices that act as intermediaries between shared clock switches and the three-state stages. These intermediary devices ensure proper signal isolation and timing, allowing clock switches to be shared without causing logic contention or unstable operation.
3Reliability
If additional pairs of complementary semiconductor devices are added to prevent logic contention, then operation stability is maintained, but device count increases
Solution Approach 1:
The additional pairs of complementary semiconductor devices are merged with the clock switch structure itself, forming integrated control units. Rather than adding completely separate components, the patent integrates these protective devices into the existing clock distribution network, minimizing the increase in overall device count while maintaining operational stability.
Data Source
AI summary
In a master-slave flip-flop, the master latch has first and second three-state stages, and a first feedback stage. The slave latch has third and fourth three-state stages, and a second feedback stage. First and second clock switches having opposite phases are provided. The first clock switch is configured in one of the first and fourth three-state stages, and the other stage shares the first clock switch. The second clock switch is configured in one of the second and third three-state stages, and the other stage shares the second clock switch. The second three-state stage has an additional pair of complementary devices having signal paths connected in series with each other with both being gated by a data output of the slave latch. The flip-flop reduces the number of clock switches and clock switch power consumption.