USB 3.0 Transmitter Detecting Circuit for Termination Resistor
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Solution Overview
Problem
USB 3.0 transmitters face challenges in detecting the presence of termination resistors when they are connected to supply voltage instead of ground, leading to compatibility issues with non-standard receiver specifications.
Innovation Solution
A detecting circuit comprising a testing signal generator and a detector that uses a combination of rising and falling edges to determine if an external circuit element is connected to a reference voltage, allowing for precise detection regardless of the termination configuration.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If the transmitter uses conventional detection methods to check for termination resistors, then it can detect standard USB 3.0 receivers with ground-connected termination, but it fails to detect non-standard receivers with supply-voltage-connected termination
Solution Approach 1:
The patent applies dynamics by making the testing signal generator produce different signal edge types (rising or falling) dynamically based on the detected signal level. When a high signal level is detected, it generates a falling edge test signal; when a low signal level is detected, it generates a rising edge test signal. This dynamic adaptation allows the transmitter to successfully detect termination resistors regardless of whether they are connected to ground or supply voltage, resolving the contradiction between detection accuracy and compatibility.
2Reliability
If the transmitter detects termination resistors connected to ground using conventional methods, then detection works for standard receivers, but detection fails when receivers connect termination to supply voltage
Solution Approach 1:
The patent applies parameter changes by modifying the testing signal characteristics (signal edge direction) based on the detected voltage level. The system changes the parameter of the testing signal from a fixed rising edge to a conditional selection between rising and falling edges. This parameter adaptation ensures reliable detection of termination resistors in both ground-connected and supply-voltage-connected configurations, resolving the contradiction between detection reliability and adaptability.
3Device complexity
If the transmitter uses a single type of testing signal edge, then the detection circuit is simple, but it cannot accurately detect external circuit elements in different termination configurations
Solution Approach 1:
The patent resolves the contradiction between device complexity and measurement precision by implementing a dynamic testing signal generator that automatically selects the appropriate signal edge type based on the detected voltage level. The generator includes level detection circuitry that conditions the choice of rising or falling edge, maintaining relatively simple circuit architecture while achieving high detection accuracy across different termination configurations.
Solution Approach 2:
The detection system applies self-service by automatically adapting its testing signal characteristics based on the received signal level without requiring external intervention or complex configuration. The system uses its own detection capabilities to determine the appropriate testing signal type, enabling accurate detection while keeping the overall system design relatively simple.
Data Source
AI summary
A detecting circuit includes: a testing signal generator, arranged to selectively generate a testing signal having a first signal edge or a second signal edge to a connecting port; and a detector, arranged to detect a first detect signal on the connecting port after the testing signal having the first signal edge is coupled to the connecting port, and to detect a second detect signal on the connecting port after the testing signal having the second signal edge is coupled to the connecting port; wherein the detector is further arranged to determine if an external circuit element is coupled between the connecting port and a reference voltage according to the first detect signal and the second detect signal.