Presettable Address Counter Circuit for Clock-Skew-Free Counting
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Solution Overview
Problem
Conventional high-speed counters are limited in their ability to input random data and control clock signals, leading to operational errors due to fixed reset states and potential clock skew, which restricts their flexibility and accuracy in counting operations.
Innovation Solution
The proposed solution involves a counting circuit with additional flip-flops and logic gates that allow for arbitrary initial value setting and synchronized clock signal control, enabling the generation of flexible counting signals and preventing operational errors by using a combination of OR and AND logic gates to manage input data and clock signals.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If a fixed reset state is used in conventional high-speed counters, then the counter structure is simple, but the ability to input random data is limited
Solution Approach 1:
The counter structure is made dynamic by allowing the reset state to be changed arbitrarily through preset control signals. The circuit can operate in different modes (fixed reset or random data input) by controlling the preset signals to the flip-flops, enabling adaptability without permanent structural modification.
Solution Approach 2:
The counter is divided into multiple independent flip-flops (first to fourth FFs) that can be individually controlled through preset signals. This segmentation allows each flip-flop to be set independently, enabling random data input while maintaining the overall counter structure.
2Productivity
If multiple high-speed counters are coupled to construct a 4-bit or 8-bit counting circuit, then the counting range is extended, but clock skew causes operational errors
Solution Approach 1:
Multiple counter units are merged into a single synchronized system by using a common clock signal and coordinating their operation through preset control signals. The fifth FF acts as a synchronization element that ensures all counters operate in unison, eliminating clock skew issues while maintaining extended counting range.
Solution Approach 2:
The circuit uses feedback mechanisms where the output of the fifth FF (which is synchronized with the clock) is used to control the operation of subsequent counter stages. This feedback ensures that each counter stage is activated only when properly synchronized, preventing operational errors from clock skew.
3Adaptability or versatility
If the counter always starts from a fixed value, then the circuit operation is simple, but flexibility in counting operations is restricted
Solution Approach 1:
The initial value of the counter is made dynamic rather than fixed. By controlling the preset signals to the flip-flops, the counter can be initialized to any desired value depending on the application requirements, providing flexibility while maintaining relatively simple circuit operation through standardized control logic.
Data Source
AI summary
A counting circuit includes first to fifth flip-flops (FFs) and a logic operation unit. Each of the first to fourth FFs has an initial value based on a preset control signal input through a 4-bit set terminal and outputs a signal according to a clock signal. The fifth FF is coupled to the output terminal of the fourth FF and is configured to output the output signal of the fourth FF synchronously with the clock signal. The logic operation unit logically combines the output signals of the second to fourth FFs and outputs first and second counting signals.