Capacitive Accessory Detection for Battery Power Conservation

Solution Overview

Problem

Battery-powered devices face a trade-off between conserving power and improving user experience when detecting accessory device connections, as keeping peripherals powered increases battery drain, while disabling detection worsens user experience.

Innovation Solution

Incorporating a capacitive sensing circuit that detects accessory device connections by monitoring input capacitance, allowing the host device to power on automatically without user input while minimizing power consumption by remaining in an extreme low power mode until an accessory is plugged in.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Ease of operation

If the peripheral is kept powered to detect accessory device connection, then the user experience is improved (automatic detection), but the battery power is drained much faster

Engineering Contradiction:

Improveautomatic accessory detectionVSAvoidbattery power consumption

Core Design Contradiction:

Ease of operationVSUse of energy by moving object

Solution Approach 1:

The patent replaces the conventional mechanical/electrical continuous monitoring system with a capacitive sensing system. The capacitive sensor detects accessory connections through changes in electrical capacitance without requiring continuous power to peripheral circuits, thereby maintaining automatic detection capability while dramatically reducing power consumption during shutdown mode.

Inventive Principle:

Principle #28Mechanics substitution (Replace mechanical system)

Solution Approach 2:

The capacitive sensor acts as an intermediary between the accessory device and the host device's main processor. It provides a low-power interface that can detect connection events and trigger the main system to wake up, eliminating the need for continuous peripheral power while preserving automatic detection functionality.

Inventive Principle:

Principle #24Intermediary (Mediator)

2Use of energy by moving object

If the peripheral is powered down to conserve battery power, then the power consumption is reduced, but the accessory device connection is not recognized until the host device is manually turned on

Engineering Contradiction:

Improvebattery power conservationVSAvoidaccessory connection recognition

Core Design Contradiction:

Use of energy by moving objectVSEase of operation

Solution Approach 1:

The patent replaces the conventional mechanical/electrical continuous monitoring system with a capacitive sensing system. The capacitive sensor detects accessory connections through changes in electrical capacitance without requiring continuous power to peripheral circuits, thereby maintaining automatic detection capability while dramatically reducing power consumption during shutdown mode.

Inventive Principle:

Principle #28Mechanics substitution (Replace mechanical system)

Solution Approach 2:

The capacitive sensor performs preliminary detection of accessory connections before the main host device is activated. When an accessory is detected, the sensor pre-triggers a wake-up signal to the main processor, ensuring that the device is already preparing to operate by the time the user needs it, thus maintaining ease of operation while conserving power.

Inventive Principle:

Principle #10Preliminary action

3Reliability

If a conventional detection circuit is used to detect accessory connection, then the connection can be detected, but the power consumption is too high for shutdown mode

Engineering Contradiction:

Improveconnection detection reliabilityVSAvoidpower consumption in shutdown mode

Core Design Contradiction:

ReliabilityVSUse of energy by moving object

Solution Approach 1:

The patent replaces the conventional mechanical/electrical continuous monitoring system with a capacitive sensing system. The capacitive sensor detects accessory connections through changes in electrical capacitance without requiring continuous power to peripheral circuits, thereby maintaining automatic detection capability while dramatically reducing power consumption during shutdown mode.

Inventive Principle:

Principle #28Mechanics substitution (Replace mechanical system)

Solution Approach 2:

The patent changes the detection parameter from continuous electrical signal monitoring to capacitive coupling measurement. This parameter change allows the system to detect accessory connections with extremely low power consumption, as capacitive sensing can be performed with minimal current draw compared to conventional active detection circuits.

Inventive Principle:

Principle #35Parameter changes

Applied Scientific Principles

This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.

Function Achieved in This Case

This solution enables automatic host device powering upon accessory connection while maintaining negligible power consumption, extending battery life and providing a seamless user experience without manual intervention.

Implementation Method 1

The capacitive sensing circuit senses the accessory device connection by detecting a change in the input capacitance at the interface connector

Methodology Applied

Scientific EffectCapacitance: Capacitance

Data Source

PatentUS10345879B2Capacitance based accessory connection detection for a battery powered unit

Publication Date: 2019.07.09 DISH TECHNOLOGIES LLC

AI summary

Devices and methods for detecting the plug-in of an accessory device by a host device are provided. A host device includes a power switch coupled between a battery and a processor. The host device is turned off by a power button coupled to the power switch. A capacitive sensing circuit is coupled to a signal line of a host device port, and is configured to detect a plug-in of the accessory device by monitoring an input capacitance of the signal line. A logic circuit is coupled to an output of the power button and to an output of the capacitive sensing circuit, and the logic circuit turns on the power switch if the power button is in an on position or if the capacitive sensing circuit detects a plug-in of the accessory device.