Clock Domain Buffering Delay Measurement Circuit
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Solution Overview
Problem
In distributed radio base stations, accurately measuring and compensating for timing differences between different clock domains is challenging, especially when data is transferred between serializer/deserializer (SERDES) and application-specific integrated circuit (ASIC) clock domains, which affects synchronization and timing accuracy.
Innovation Solution
A buffer circuitry is used to bridge the clock domains, with counting circuitry accumulating a count value between write and read timing signals to determine the buffering delay, allowing control circuitry to compensate for phase differences, thereby enabling precise synchronization.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If data is transferred between SERDES and ASIC clock domains using a buffer, then data transfer between different clock domains is enabled, but buffering delay occurs causing timing inaccuracies
Solution Approach 1:
A timing measurement circuit is introduced as an intermediary component between the buffer and the clock domains. This circuit measures the buffering delay by detecting write timing signals from the first clock domain and read timing signals from the second clock domain, accumulating count values to determine the exact delay introduced by the buffer. This intermediary measurement mechanism enables precise timing compensation while maintaining the buffer's data transfer function.
Solution Approach 2:
The patent implements a feedback mechanism where the measured buffering delay is fed back to the control circuitry. The control circuitry uses this delay information to adjust timing parameters and compensate for the buffering delay, creating a closed-loop system that continuously optimizes timing accuracy. This feedback approach allows the system to adapt to varying buffer delays and maintain synchronization between clock domains.
2Measurement precision
If timing measurement circuitry is added to measure buffering delay, then timing accuracy is improved, but device complexity increases
Solution Approach 1:
The timing measurement circuit is designed to perform multiple functions: it measures write timing from the first clock domain, measures read timing from the second clock domain, accumulates count values to determine delay, and provides timing information to the control circuitry. By consolidating these functions into a single multi-functional circuit block, the patent reduces overall system complexity compared to using separate dedicated circuits for each function.
Solution Approach 2:
The patent merges the timing measurement functionality with the existing buffer control infrastructure. The timing measurement circuit is integrated into the buffer control logic, sharing common resources such as clock signals, control buses, and processing units. This merging approach allows the timing measurement feature to be added without proportionally increasing device complexity, as it leverages existing circuit elements and interconnections.
Data Source
AI summary
Buffer circuitry receives data to be processed by electronic circuitry using a first clock signal associated with a first clock domain. The buffered data is output using a second clock signal associated with a second clock domain. The buffering of the data is associated with a buffering delay. Counting circuitry receives at a start count input a write timing signal associated with the first clock domain and with writing data to the buffer circuitry. The counting circuitry receives at a stop count input a read timing signal associated with the second clock domain and with reading data from the buffer circuitry. A count value accumulated between receiving the write timing signal and the read timing signal corresponds to the buffering delay. Control circuitry performs a control operation based on the count value.