USB Disconnection Detection Circuit with Adaptive Voltage Reference

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Solution Overview

Problem

The increasing internal resistances of hosts and devices in USB systems lead to false disconnection detection due to the inability to set an appropriate determination voltage, causing issues with accurate disconnection detection.

Innovation Solution

A circuit device with a HS driver and disconnection detection circuit that includes a holding circuit to measure voltage level information during a host chirp, a determination voltage generation circuit to generate a determination voltage based on this information, and a detection circuit to perform disconnection detection using this voltage, allowing for accurate disconnection detection regardless of changing connection conditions.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If a fixed determination voltage is used for disconnection detection, then the circuit structure is simple, but false disconnection detection occurs due to increasing internal resistances

Engineering Contradiction:

Improvedisconnection detection accuracyVSAvoidcircuit structure

Core Design Contradiction:

ReliabilityVSDevice complexity

Solution Approach 1:

The holding circuit measures and stores the voltage level of the differential output signal before disconnection detection is performed. This preliminary measurement allows the determination voltage generation circuit to set an appropriate determination voltage based on the actual voltage level, preventing false disconnection detection due to internal resistance changes.

Inventive Principle:

Principle #10Preliminary action

Solution Approach 2:

The determination voltage generation circuit generates the determination voltage based on the stored voltage level information from the holding circuit. This feedback mechanism ensures that the determination voltage adapts to changes in internal resistance and voltage level, maintaining accurate disconnection detection without increasing circuit complexity significantly.

Inventive Principle:

Principle #23Feedback

2Adaptability or versatility

If the determination voltage is increased to cope with higher internal resistance, then disconnection detection can handle higher resistance, but false disconnection detection occurs at normal operating voltages

Engineering Contradiction:

Improvecopability with internal resistanceVSAvoidfalse disconnection detection

Core Design Contradiction:

Adaptability or versatilityVSReliability

Solution Approach 1:

The determination voltage generation circuit dynamically adjusts the determination voltage based on the actual voltage level stored in the holding circuit. When the differential output signal voltage level is high, the determination voltage is set higher; when the voltage level is normal, the determination voltage is set accordingly. This parameter adaptation allows the system to cope with varying internal resistance without causing false disconnection detection.

Inventive Principle:

Principle #35Parameter changes

Data Source

PatentUS11598823B2Circuit device, electronic device, and vehicle

Publication Date: 2023.03.07 SEIKO EPSON CORP

AI summary

A circuit device includes an HS driver that is a USB HS-mode transmission circuit and a disconnection detection circuit that performs disconnection detection of USB. The disconnection detection circuit includes a holding circuit that measures and holds first voltage level information that is voltage level information of one signal out of a DP signal and a DM signal of the USB when the HS driver is transmitting a host chirp, a determination voltage generation circuit that generates a first determination voltage based on the first voltage level information, and a detection circuit that performs disconnection detection of the USB based on the first determination voltage and outputs a disconnection detection signal.