On-Chip Jitter Sensor Circuit Using Random Time-to-Voltage Sampling
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Solution Overview
Problem
Existing computer systems face challenges in accurately measuring clock jitter due to variations in clock generation circuits and operating conditions, which can lead to timing failures and hinder high-speed data communication, and off-chip measurements introduce inaccuracies.
Innovation Solution
A jitter sensor circuit is implemented on-chip, comprising a time-to-voltage converter, analog-to-digital converter, and control circuit, which measures jitter by generating a sample signal proportional to the clock signal's period and digitizes it using a reference voltage, reducing power consumption and dynamic range requirements through random sampling and calibration.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If off-chip jitter measurement is used, then measurement capability is provided, but measurement accuracy deteriorates due to introduced inaccuracies
Solution Approach 1:
The jitter sensor circuit merges the jitter measurement functionality directly into the chip with the clock generation circuits. The time-to-voltage converter, analog-to-digital converter, and control circuit are integrated on the same chip, eliminating the need for separate off-chip measurement equipment and connections that introduce inaccuracies.
Solution Approach 2:
The patent introduces an on-chip intermediary measurement system that captures jitter characteristics directly at the source. The time-to-voltage converter acts as an intermediary that transforms timing variations into voltage signals for accurate measurement without external interference.
2Measurement precision
If traditional jitter measurement circuits are implemented, then jitter detection is enabled, but power consumption increases
Solution Approach 1:
The control circuit activates the time-to-voltage converter and analog-to-digital converter in periodic sampling intervals rather than continuously. This periodic operation enables jitter measurement capability while significantly reducing average power consumption compared to continuous monitoring circuits.
Solution Approach 2:
The patent changes the operational parameters of the measurement circuit by using random sampling intervals and adjusting the activation timing of the converter circuits. This parameter optimization reduces power consumption while maintaining measurement accuracy.
3Measurement precision
If high dynamic range is used for jitter measurement, then measurement accuracy is improved, but device complexity and power consumption increase
Solution Approach 1:
The patent uses partial action by implementing random sampling that captures sufficient jitter characteristics without requiring full continuous monitoring. This approach achieves adequate measurement range and accuracy without the complexity of high-dynamic-range continuous measurement circuits.
Solution Approach 2:
The patent replaces complex mechanical or electronic high-dynamic-range measurement mechanisms with a simplified time-to-voltage conversion approach. The analog-to-digital converter uses reference voltage comparison rather than complex multi-range measurement mechanisms, reducing circuit complexity while maintaining measurement capability.
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
On-chip jitter measurement eliminates off-chip inaccuracies and allows for accurate jitter assessment during normal operation, improving timing precision and reducing power consumption.
Implementation Method 1
A time-to-voltage converter circuit may be configured, in response to being activated, to generate a sample signal using the reference voltage. A voltage level of the sample signal may be proportional to a portion of a period of the input signal.
Implementation Method 2
An analog-to-digital converter circuit may be configured to generate, using the reference voltage, an output signal based on the sample signal.
Data Source
AI summary
A jitter sensor circuit for measuring jitter of a clock signal is disclosed. The jitter sensor circuit includes a time-to-voltage converter circuit that is activated at random intervals to generate, using a reference voltage, a signal whose voltage is proportional to a portion of a period of the clock signal. The jitter sensor circuit also includes an analog-to-digital converter circuit that converts the output signal of the time-to-voltage converter circuit to a digital value using the same reference voltage as the time-to-voltage converter circuit.