Wearable Current Limiting for Skin-Safe Thermal Control
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Solution Overview
Problem
Wearable devices such as smart watches experience undesired heating due to high current draw, which can be caused by electrical or mechanical malfunctions, and existing temperature monitoring systems are inadequate in preventing these increases, especially when in contact with the user's skin.
Innovation Solution
A wearable computing device with control circuitry that identifies a power consumption threshold and restricts current draw using a current limiter component when excessive current is detected, employing a watchdog strategy to prevent overheating by activating a current limiter component based on a signal from the components, thereby regulating current and preventing temperature increases on the external surface.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Power
If a lithium ion battery provides high electric current to components in a wearable device, then the power supply capability is improved, but the temperature of the external surface increases undesirably due to current draw and thermal dissipation limitations
Solution Approach 1:
The patent implements a current monitor component that continuously monitors current draw before excessive current can cause harmful heating. The system takes preliminary action by detecting current thresholds and activating a current limiter component to restrict current flow, preventing temperature increases before they occur. This proactive approach allows the battery to provide high power when needed while preemptively preventing thermal hazards.
2Measurement precision
If a thermistor-based temperature monitoring system is used to infer PCB temperature, then temperature monitoring capability is improved, but the system cannot prevent undesired temperature increases due to high thermal conductivity of sensor pins contacting user skin
Solution Approach 1:
The patent introduces a current monitor component as an intermediary between the power source and components, and a current limiter component as another intermediary to control current flow. Instead of relying on thermistors that conduct heat to sensor pins, the system uses electrical current monitoring as an intermediary measurement method that does not compromise thermal isolation. The current limiter acts as an intermediary control mechanism that restricts current before it can generate harmful heat, providing reliable temperature control without the thermal conduction problem.
3Temperature
If current draw is restricted to prevent heating, then temperature control is improved, but the power consumption model must be continuously monitored and managed
Solution Approach 1:
The patent implements a self-service system where the current monitor component automatically continuously monitors current draw and compares it against threshold values stored in memory. The control circuitry autonomously determines when to activate the current limiter component based on monitored current levels, without requiring complex external management. The system serves itself by having the monitor detect conditions and trigger the limiter automatically, simplifying power consumption management while maintaining effective temperature control.
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 effectively prevents undesired heating by regulating current draw, providing a more comprehensive and faster response than traditional thermistor-based systems, ensuring user comfort and component safety by limiting current when it exceeds a predetermined threshold.
Implementation Method 1
a current monitor component to measure current draw from the power source
Implementation Method 2
a current limiter component to restrict current draw from the power source
Implementation Method 3
there is a risk that an electrical or mechanical malfunction could result in significant current draw (errant power dissipation) resulting in an undesired increase in temperature
Data Source
AI summary
Apparatuses, methods and storage medium associated with restricting current draw in wearable devices are disclosed herein. In embodiments, a wearable computing device may include a power source, one or more components coupled with each other and to the power source to perform wearable computing; and control circuitry coupled with the one or more components, the control circuitry to: identify a threshold selected based on a power consumption model of the wearable computing device; ascertain whether current draw from the power source is greater than the threshold; and restrict the current draw from the power source of the wearable computing device based on a signal output from one of the one or more components, in response to the current draw is ascertained to be greater than the threshold. Other embodiments may be disclosed or claimed.