eUSB2 Repeater Circuit for Accurate USB EOP Detection
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Solution Overview
Problem
The implementation of eUSB2 repeaters faces challenges in detecting the end of a USB packet (EOP) indicator accurately, leading to noise transmission due to hub switching skews, especially when conventional USB and eUSB2 systems operate at different voltage levels, and existing solutions like CDR circuits and PLLs are large, increasing cost and power consumption.
Innovation Solution
A circuit that includes amplifiers, comparators, and a logic circuit to detect differential input signal idle conditions, maintaining the last bit of the EOP indicator for up to four additional bits to prevent noise, without using a CDR circuit or PLL, thereby facilitating level-shifting between eUSB2 and USB voltage levels.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If CDR circuits and PLLs are used to detect EOP indicator, then detection accuracy is improved, but device size and power consumption increase
Solution Approach 1:
The patent extracts the essential detection function from complex CDR circuits and PLLs by using only a comparator to detect voltage level transitions. This removes unnecessary components while retaining the core capability of detecting EOP indicators, thereby reducing device size and power consumption while maintaining detection accuracy.
Solution Approach 2:
The patent replaces expensive, complex CDR circuits and PLLs with a simple, low-cost comparator that consumes minimal power. The comparator is a basic electronic component that provides sufficient detection capability for the application, effectively substituting high-cost solutions with a economical alternative that meets the functional requirements.
2Measurement precision
If CDR circuits and PLLs are used to detect EOP indicator, then detection accuracy is improved, but power consumption increases
Solution Approach 1:
The patent replaces power-hungry CDR circuits and PLLs with a minimal-power comparator. The comparator consumes significantly less power while providing adequate detection accuracy for EOP indicators, thereby resolving the contradiction between detection precision and power consumption.
Solution Approach 2:
The patent extracts only the essential voltage level detection function from power-intensive CDR and PLL circuits, implementing it with a simple comparator. This extraction eliminates the power-consuming aspects of the original circuits while preserving the detection capability needed for accurate EOP indicator identification.
3Adaptability or versatility
If conventional USB and eUSB2 systems operate at different voltage levels, then system compatibility is improved, but noise transmission increases due to hub switching skews
Solution Approach 1:
The patent uses the comparator to detect voltage level transitions before data transmission occurs, identifying EOP indicators in advance. By detecting the end of packets beforehand, the system can prepare for upcoming voltage level changes and hub switching events, preventing noise transmission while maintaining compatibility between different voltage levels.
Data Source
AI summary
Aspects of the disclosure provide for a method. In at least some examples, the method includes receiving, at a circuit, data via a differential input signal. The method further includes detecting a falling edge in the data received via the differential input signal. The method further includes holding an output of the circuit at a final logical value of the data. The method further includes disabling a transmitter of the circuit while holding the output of the circuit at the final logical value of the data. The method further includes releasing the output of the circuit from the final logical value of the data.