Printer Control Circuit Power Management for USB Initialization
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Electronic devices face issues with power wastage and reduced battery life due to failed initialization processes when connected to external devices, particularly when the host device cannot supply the requested power, leading to prolonged CPU activation and unnecessary charging attempts.
Innovation Solution
The electronic device performs a first initialization process and only receives power after completion, skips charging if the first process fails, and initiates a second initialization process with reduced power requirements if the first fails, thereby avoiding power wastage and depletion.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Power
If the electronic device performs initialization process and requests second power from host device, then the device can receive higher power supply for charging, but the CPU remains in active state waiting for initialization completion notification that may never arrive, causing power wastage
Solution Approach 1:
The electronic device performs a preliminary check by detecting whether the host device is capable of supplying the requested second power before completing the initialization process. This preliminary detection prevents the CPU from entering a prolonged active waiting state, thereby avoiding power wastage while still enabling high-power charging when appropriate.
Solution Approach 2:
The system implements feedback by monitoring the initialization process completion status and the host device's power supply capability. When the host device fails to send the initialization completion notification or is detected as incapable of supplying requested power, the electronic device receives this feedback and terminates the initialization process, preventing continued power consumption in an active state.
2Reliability
If the electronic device waits for initialization process completion notification, then proper communication establishment is ensured, but battery life is reduced due to prolonged CPU activation and power consumption
Solution Approach 1:
The electronic device performs preliminary detection of the host device's power supply capability during the initialization process. This preliminary action allows the device to determine in advance whether the host can supply the requested power, preventing prolonged CPU activation and preserving battery life while ensuring reliable communication when the host is capable.
Solution Approach 2:
The system uses feedback from the initialization process status and host device responses to determine when to terminate waiting. When feedback indicates the host device cannot supply requested power or fails to send completion notification, the electronic device stops waiting and transitions to a low-power state, thus preserving battery life while maintaining communication reliability when appropriate.
3Productivity
If the electronic device requests second power greater than first power, then charging speed increases, but the initialization process may fail when host device is connected via hub or battery-driven, leaving CPU in active state
Solution Approach 1:
The electronic device performs preliminary detection of the host device type and power supply capability before completing the initialization process for second power. This preliminary action identifies situations where the host is connected via hub or battery-driven, allowing the device to avoid requesting second power in these cases and prevent initialization failure, thus ensuring reliable charging process completion.
Solution Approach 2:
The system implements feedback monitoring during initialization to detect whether the host device can supply the requested second power. When feedback indicates initialization failure or host incapability, the electronic device receives this information and terminates the initialization process appropriately, preventing prolonged CPU activation and ensuring reliable charging outcomes.
4Reliability
If the electronic device continuously monitors for initialization completion notification, then communication reliability is maintained, but power consumption increases and battery depletes
Solution Approach 1:
The electronic device performs preliminary detection of host device capability and initialization status before continuously monitoring for completion notification. This preliminary action establishes baseline information that allows the device to terminate monitoring early when appropriate, maintaining communication reliability while reducing unnecessary power consumption during CPU active state.
Solution Approach 2:
The system uses feedback from the initialization process and host device responses to dynamically adjust monitoring behavior. When feedback indicates the host cannot supply requested power or initialization is failing, the electronic device stops continuous monitoring and transitions to low-power state, thus maintaining communication reliability while significantly reducing power consumption and battery depletion.
Data Source
AI summary
When a control circuit of a printer detects a USB connection with a host device when a power switch is in an on state in an initial state, the control circuit performs an initialization process (enumeration) (a first initialization process) which requests bus power, and performs a USB communication process and charging of a secondary cell after the first initialization process is completed (successful). When the first initialization process fails, the control circuit performs an initialization process requesting self power (a second initialization process), and does not perform charging of the secondary cell. Here, the first initialization process includes a request for a greater supply of power than the second initialization process.