Smart Sensor DSP Integration for Low-Power Always-On Wake Detection
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Solution Overview
Problem
Conventional mobile devices face inefficiencies in power management due to power-intensive microprocessors and sensors that lead to reduced battery life, as they remain energized to detect interactions even in 'sleep' modes, resulting in inaccurate wake events and increased power consumption.
Innovation Solution
The integration of microelectromechanical systems (MEMS) sensors with a digital signal processor (DSP) within a package, enabling self-contained processing and decision-making for smart sensors that can operate in always-on, low-power modes, allowing for more precise wake-up events and reduced power consumption.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If sensors and associated circuits are energized to constantly monitor device environment, then wake events can be detected, but power consumption increases and battery life decreases
Solution Approach 1:
The sensor circuit includes an on-chip comparator and processing logic that autonomously evaluates sensor outputs against reference values and generates wake events without requiring external processor intervention. This self-service capability allows the sensor to operate independently at low power while reliably detecting wake events.
Solution Approach 2:
An on-chip comparator serves as an intermediary between the sensor element and the external processor. It processes sensor signals locally and only activates the power-intensive processor when a genuine wake event is detected, thereby reducing unnecessary power consumption while maintaining reliable wake event detection.
2Reliability
If general purpose logic or power management components are used to monitor sensors, then wake events can be processed, but power consumption increases due to processor activation
Solution Approach 1:
The wake event processing function is segmented into two parts: simple threshold comparison and signal processing are performed by on-chip circuits, while the power-intensive processor is activated only for complex decision-making. This segmentation reduces processor activation and associated power consumption.
Solution Approach 2:
The on-chip comparator acts as an intermediary that filters and pre-processes sensor signals before they reach the external processor. By handling routine monitoring tasks locally, it prevents unnecessary processor activation and reduces power consumption while maintaining reliable wake event processing.
3Reliability
If sensors operate in always-on mode to detect interactions, then wake events are captured, but battery life is reduced due to continuous power drainage
Solution Approach 1:
The sensor circuit autonomously manages its own operation by continuously monitoring environmental conditions and independently generating wake events when thresholds are met. This self-service approach eliminates the need for continuous processor involvement, extending battery life while maintaining reliable interaction detection.
Solution Approach 2:
The sensor operates in a periodic monitoring mode where it continuously samples environmental conditions but only activates wake events when predetermined thresholds are exceeded. This periodic action with event-driven activation reduces average power consumption while maintaining reliable interaction detection capability.
Data Source
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AI summary
Smart sensors comprising one or more microelectromechanical systems (MEMS) sensors and a digital signal processor (DSP) in a sensor package are described. An exemplary smart sensor can comprise a MEMS acoustic sensor or microphone and a DSP housed in a package or enclosure comprising a substrate and a lid and a package substrate that defines a back cavity for the MEMS acoustic sensor or microphone. Provided implementations can also comprise a MEMS motion sensor housed in the package or enclosure. Embodiments of the subject disclosure can provide improved power management and battery life from a single charge by intelligently responding to trigger events or wake events while also providing an always on sensor that persistently detects the trigger events or wake events. In addition, various physical configurations of smart sensors and MEMS sensor or microphone packages are described.