Always-On Audio Capture Block for Low-Power SoC Standby
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Solution Overview
Problem
Mobile devices often operate in low power modes to conserve energy, but existing systems face challenges in efficiently managing power consumption while maintaining standby functionality, particularly in capturing and processing sensor data without waking up the entire System on a Chip (SOC).
Innovation Solution
An always-on block within the SOC remains powered to capture sensor data, buffer it, and process it selectively, allowing for reduced power consumption by only activating necessary components, such as the memory controller and communication paths, while storing programmable configuration data to reprogram other components upon wake-up.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Use of energy by moving object
If the SOC is fully powered down to eliminate leakage current losses, then energy consumption is reduced, but the device cannot capture or process sensor data during standby mode
Solution Approach 1:
The SOC is divided into multiple power domains: an always-on low-power domain that maintains sensor capture and basic processing capabilities, and a main domain that can be powered down. This segmentation allows the device to maintain essential standby functionality while minimizing power consumption by keeping only the critical always-on component active during low-power modes.
2Productivity
If the entire SOC is powered up to process sensor data, then processing capability is improved, but power consumption increases significantly
Solution Approach 1:
Instead of fully powering up the SOC for sensor data processing, the system performs partial processing in the always-on domain by filtering data and detecting patterns. Only when processing thresholds are met does the system wake up the main domain, thereby achieving necessary processing capability while avoiding the high power consumption of full SOC activation.
Solution Approach 2:
The always-on component performs preliminary filtering and pattern detection on sensor data before it reaches the main processing domain. This preliminary action reduces the volume and complexity of data requiring full SOC processing, thereby maintaining productivity while minimizing the duration and frequency of high-power states.
3Speed
If sensor data is continuously processed in the always-on component, then responsiveness is improved, but the component's power consumption increases
Solution Approach 1:
The always-on component employs periodic polling and event-driven processing rather than continuous operation. It captures sensor data at optimized intervals and activates full processing only when specific events or thresholds are detected, thereby maintaining system responsiveness while minimizing the active processing time and associated power consumption of the always-on component.
Data Source
AI summary
In an embodiment, a system on a chip (SOC) includes a component that remains powered when a central processing unit (CPU) processor and a memory controller of the SOC are powered off. The component may include a sensor capture unit to capture audio samples from an audio detector circuit and write them to a memory of the component. A processor of the component may be configured to search the audio samples for a predetermined pattern during a time when the CPU processor and the memory controller are powered down. In some embodiments, based on the audio samples filling to a threshold level in the memory of the component and a lack of detection of the predetermined pattern, the component is configured to wake up the memory controller and a path to the memory controller in order to write the audio sample to a memory controlled by the memory controller.