Asynchronous State Machine Deep Sleep Power Management
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Solution Overview
Problem
Portable battery-powered devices face challenges in managing power consumption, especially when in the 'OFF' state, leading to battery drain during storage or shipment, and existing power management systems may not effectively conserve battery life.
Innovation Solution
An asynchronous state machine (ASM) is implemented to manage deep sleep states, allowing devices to enter a low-power state with only the ASM and real-time clock powered, and automatically initiating a wake-up sequence upon user input or external power attachment, enabling power management functions as needed.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Loss of energy
If the device is completely powered off to conserve battery power, then battery consumption is minimized, but the device cannot respond to user input or external power attachment
Solution Approach 1:
The power management system is segmented into multiple operational states (deep sleep mode and awake mode) with distinct functionality. In deep sleep mode, only essential components (ASM, real-time clock) remain powered while other components are powered down, allowing the device to minimize energy consumption while maintaining basic wake-up capabilities through hardware signals from power user-interface elements or external power attachment detection
Solution Approach 2:
The asynchronous state machine (ASM) acts as an intermediary component that remains powered during deep sleep mode to monitor wake-up conditions. The ASM detects signals from power user-interface elements (such as power buttons or switches) and external power attachment, then initiates the wake-up sequence by enabling the power management function and transferring control to it, thereby bridging the gap between complete power-off and full device operation
2Speed
If power management functions remain enabled during deep sleep state, then the device can quickly wake up, but battery shelf life during storage and shipment is reduced
Solution Approach 1:
The power management system divides functionality into essential (ASM, real-time clock) and non-essential (power management function, other device components) segments. During deep sleep state, only essential components remain powered to preserve battery shelf life, while non-essential components are powered down. The ASM monitors wake-up triggers and initiates a controlled wake-up sequence that enables power management functions only when needed
Solution Approach 2:
The system implements periodic monitoring of wake-up conditions by the ASM without requiring continuous operation of power management functions. The ASM periodically checks for wake-up triggers (power user-interface element status changes or external power attachment) and only activates the full power management system when a wake-up event is detected, thereby reducing overall power consumption during storage and shipment while maintaining quick wake-up capability
3Loss of energy
If the device enters deep sleep state with minimal components powered, then battery power is conserved, but the device cannot autonomously manage wake-up sequences
Solution Approach 1:
The asynchronous state machine (ASM) is designed to autonomously manage the wake-up sequence without requiring external intervention or full power management function operation. When the ASM detects a wake-up trigger (change in power user-interface element status or external power attachment), it automatically initiates the wake-up sequence by enabling the power management function and transferring control to it, thereby providing self-service wake-up management while keeping battery power consumption minimal during deep sleep state
Data Source
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AI summary
An asynchronous state machine (ASM) for managing deep sleep state of a device and related methods are described. One method includes the ASM automatically detecting a request to wake up the device based on either a change in a status of a power user-interface element associated with the device or upon a detection of an attachment of an external power source to the device. The method further includes the ASM automatically initiating a wake-up sequence including turning on a battery pack associated with the device. The method further includes the ASM automatically detecting whether a power management function associated with the device is enabled and automatically transferring control of a remaining portion of the wake-up sequence to the power management function and the ASM passing the status of the power user-interface element to the power management function as needed.