Clock Alignment Circuitry for Multi-Channel ADC and DAC Timing
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Solution Overview
Problem
High-speed digital-to-analogue converter (DAC) and analogue-to-digital converter (ADC) circuitry face challenges in synchronizing clock signals across multiple channels, leading to potential output misalignment and noise due to varying delays in clock signal distribution.
Innovation Solution
The proposed solution involves alignment circuitry with clocked latches, delay circuits, and gating circuitry to synchronize clock signals, and calibration circuitry with phase detectors and comparators to adjust delays, ensuring precise timing alignment across channels.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Speed
If clock signals are distributed across multiple channels in high-speed DAC and ADC circuitry, then the circuit can process high-speed data, but the timing alignment between channels deteriorates due to varying delays
Solution Approach 1:
The patent implements a feedback mechanism where the output of each channel is fed back to a common summing junction, and the summed output is used to adjust the timing of subsequent clock cycles. This feedback loop continuously compensates for timing misalignments that occur during high-speed operation, maintaining synchronization across multiple channels without reducing processing speed
Solution Approach 2:
The patent applies preliminary timing adjustment to clock signals before they are distributed to different channels. By pre-synchronizing the clock edges and using preliminary alignment circuitry to equalize path delays, the system ensures that all channels start processing data at precisely aligned time points, preventing timing skew from developing during high-speed operation
2Manufacturing precision
If calibration circuitry is added to synchronize clock signals, then timing alignment improves, but device complexity increases
Solution Approach 1:
The patent merges the calibration function with the existing summing junction and feedback pathway. Instead of adding separate calibration circuits for each channel, the system combines timing adjustment functionality into the common output path, allowing a single calibration mechanism to synchronize all channels simultaneously, thereby minimizing the increase in device complexity
Solution Approach 2:
The patent designs the calibration circuitry to serve multiple functions: it not only synchronizes timing across channels but also maintains synchronization during high-speed operation and provides continuous adjustment through the feedback mechanism. This multi-functional approach eliminates the need for separate calibration circuits, reducing overall device complexity while achieving precise timing alignment
Data Source
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AI summary
Alignment circuitry for use with clock-controlled circuitry, the alignment circuitry comprising: a first clocked latch configured to receive a synchronization signal having an enable edge and a target clock signal and to output an enable signal having an enable edge corresponding to the enable edge of the synchronization signal and synchronized with the target clock signal; a second clocked latch configured to receive the enable signal and a delayed target clock signal, being a version of the target clock signal having been delayed by a delay circuit of the clock-controlled circuitry, and to output a re-timed enable signal having an enable edge corresponding to the enable edge of the enable signal and synchronized with the delayed target clock signal; and gating circuitry configured to receive the delayed target clock signal and the re-timed enable signal and to start output of the delayed target clock signal at a timing defined by the enable edge of the re-timed enable signal for controlling the clock-controlled circuitry.