Low-Power USB ID Detection for MCU Shutdown Wake-Up

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Solution Overview

Problem

Microcontroller units (MCUs) in USB devices cannot detect the insertion of a USB plug in shutdown mode without additional user stimulus, leading to inefficiencies in power consumption and functionality.

Innovation Solution

Incorporating ID detection circuitry in the USB physical layer (PHY) circuit of the MCU, which monitors the ID pinout to detect the insertion of a micro-A plug, enabling detection without waking up the MCU from shutdown mode.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Use of energy by moving object

If the MCU enters shutdown mode to minimize power consumption, then power efficiency is improved, but the ability to detect USB plug insertion is lost

Engineering Contradiction:

Improvepower consumptionVSAvoiddetection capability

Core Design Contradiction:

Use of energy by moving objectVSReliability

Solution Approach 1:

The USB detection system is segmented into two independent parts: a low-power ID detection circuit that remains active during shutdown mode, and the full USB PHY controller that operates only when needed. This segmentation allows the system to maintain basic detection functionality while minimizing power consumption by keeping only the essential monitoring circuitry active.

Inventive Principle:

Principle #1Segmentation

Solution Approach 2:

The ID detection circuit automatically monitors the ID pinout and detects plug insertion events without requiring MCU intervention or user stimulus. When a plug is detected, the circuit self-activates the USB PHY controller, enabling the system to service itself from a low-power state without external triggering.

Inventive Principle:

Principle #25Self-service

2Reliability

If the MCU remains in active mode to detect USB plug insertion, then detection capability is maintained, but power consumption increases

Engineering Contradiction:

Improvedetection capabilityVSAvoidpower consumption

Core Design Contradiction:

ReliabilityVSUse of energy by moving object

Solution Approach 1:

The system separates detection functionality from full processing operations. The ID detection circuit handles the specific task of monitoring plug insertion independently, while the USB PHY controller remains in a low-power state until activation is required. This segmentation eliminates the need for continuous full-system operation.

Inventive Principle:

Principle #1Segmentation

Solution Approach 2:

The ID detection circuit acts as an intermediary between the physical USB connection and the USB PHY controller. It monitors the ID pinout and conditions the activation signal to the PHY controller, allowing the system to transition from low-power to active state only when a plug is actually detected, rather than requiring continuous monitoring.

Inventive Principle:

Principle #24Intermediary (Mediator)

3Use of energy by moving object

If additional user stimulus is required to wake the MCU from shutdown mode, then power consumption is minimized, but ease of operation deteriorates

Engineering Contradiction:

Improvepower consumptionVSAvoidoperational convenience

Core Design Contradiction:

Use of energy by moving objectVSEase of operation

Solution Approach 1:

The system performs self-detection of USB plug insertion through the ID detection circuit, which continuously monitors the ID pinout even in shutdown mode. This eliminates the need for user intervention to wake the system, as the detection circuit automatically identifies connection events and triggers the appropriate response without requiring button presses or other user stimuli.

Inventive Principle:

Principle #25Self-service

Solution Approach 2:

The ID detection circuit is pre-configured to monitor the ID pinout and detect plug insertion events before the USB PHY controller needs to become active. This preliminary detection capability ensures that the system is already aware of the connection status before full operation is required, enabling automatic wake-up without user stimulus.

Inventive Principle:

Principle #10Preliminary action

4Use of energy by moving object

If the USB PHY controller is disabled in shutdown mode to minimize power consumption, then power efficiency is improved, but detection precision deteriorates

Engineering Contradiction:

Improvepower consumptionVSAvoiddetection accuracy

Core Design Contradiction:

Use of energy by moving objectVSMeasurement precision

Solution Approach 1:

The detection system is divided into a minimal-power ID detection circuit and a full-featured USB PHY controller. The ID detection circuit uses only the necessary components to monitor the ID pinout for plug insertion, consuming minimal power while maintaining adequate detection precision for its specific function. The full PHY controller remains dormant until activation is required.

Inventive Principle:

Principle #1Segmentation

Data Source

PatentUS20250291762A1Methods and apparatus to enable status change detection in a low power mode of a microcontroller unit

Publication Date: 2025.09.18 TEXAS INSTRUMENTS INC

AI summary

Methods, apparatus, systems, and articles of manufacture to enable status change detection in a low power mode of a microcontroller unit are disclosed herein. An example integrated circuit (IC) includes a controller to determine that the IC is to enter a low power mode. The example IC includes a universal serial bus (USB) physical layer integrated circuit including a transceiver and a detector circuit. The transceiver is disabled while in the low power mode. The detector circuit is enabled while in the low power mode. The detector circuit is to determine whether a pinout of a USB receptacle is shorted to ground. The example IC includes a power control module (PCM) to disable the controller when entering the low power mode. Upon receipt of an indication that the ID pinout of the USB receptacle is shorted to the ground, the PCM initiates a boot sequence.