USB Repeater Squelch and Disconnect Detection With Shared Thresholds
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Solution Overview
Problem
USB2.0 technology faces challenges in power efficiency and reliability due to increased device density and manufacturing costs associated with 3.3V IO signaling, necessitating a low voltage solution for enhanced inter-chip interconnects.
Innovation Solution
A circuit combining squelch and disconnect detectors in a USB repeater, enabled or disabled by a signal, with a threshold generator and switchable RC network to optimize detection thresholds and reduce silicon area, allowing time multiplexing of detection functions for improved power efficiency.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If separate squelch detector and disconnect detector circuits are implemented, then detection functionality is complete, but silicon area increases and power consumption increases
Solution Approach 1:
The patent combines separate squelch detector and disconnect detector circuits into a single integrated detector unit. The combined circuit uses shared components including a common comparator, threshold generator, and detection logic to perform both squelch detection (detecting signal presence/absence) and disconnect detection (detecting cable removal) functions, thereby reducing silicon area while maintaining complete detection functionality.
Solution Approach 2:
The integrated detector is designed to perform multiple detection functions universally. A single detector circuit can operate in different modes (squelch detection mode and disconnect detection mode) by receiving different configuration signals, allowing one circuit to replace multiple specialized circuits and reduce overall device complexity and area.
2Reliability
If separate squelch detector and disconnect detector circuits are implemented, then detection functionality is complete, but power consumption increases
Solution Approach 1:
The patent merges separate detector circuits into a single integrated unit that shares power-consuming components such as the comparator, threshold generator, and reference voltage circuits. This consolidation eliminates redundant power consumption from duplicate circuitry while maintaining both squelch and disconnect detection capabilities.
Solution Approach 2:
The integrated detector can be activated periodically or on-demand based on system state rather than continuously operating multiple separate detectors. The circuit responds to specific trigger conditions (such as transition to high-speed mode or expected disconnect events) to perform detections only when necessary, reducing overall power consumption.
3Device complexity
If fixed detection thresholds are used, then circuit design is simple, but adaptability to different USB modes (LS, FS, HS) is limited
Solution Approach 1:
The detector incorporates dynamic threshold adjustment capability where detection thresholds are not fixed but can be configured based on operational mode. The circuit receives configuration signals that dynamically set appropriate threshold values for different USB modes (low-speed, full-speed, high-speed), allowing the same circuit to adapt to varying signal characteristics across modes.
Solution Approach 2:
The patent implements parameter changeability in the detection thresholds. By receiving configuration data that specifies threshold values, the circuit can change its detection parameters to match different USB communication modes, thereby achieving versatility without requiring multiple fixed-threshold circuits for each mode.
Data Source
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AI summary
A circuit is disclosed. The circuit includes an input port, an output port, a squelch detector and a disconnect detector. The squelch detector and the disconnect detector are enabled or disabled by a signal such that only one of the squelch detector and the disconnect detector is active at a given time. When the squelch detector is active, a threshold generator generates a squelch threshold for the squelch detector based on a squelch configuration data indicative of a predefined squelch threshold. When the disconnect detector is active, the threshold generator generates a disconnect threshold for the disconnect detector based on a disconnect configuration data indicative of a predefined disconnect threshold.