I2C Wake-Up Circuit Using Preliminary Address Signal Detection
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Solution Overview
Problem
Existing methods for waking up I2C devices are inefficient and often fail to ensure timely and normal operation, as they can only be powered off or restarted to recover normal operation after a glitch during the wake-up sequence.
Innovation Solution
A method and circuit that determine if a start signal is received, identify the next signal as an address signal, and generate a wake-up signal when matched with the I2C device's address, ensuring efficient and timely waking of the device.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Use of energy by moving object
If the I2C device is set to dormant state to save energy, then energy consumption is reduced, but the device cannot be woken up timely and normally due to glitches in the wake-up sequence
Solution Approach 1:
The patent applies preliminary action by detecting the start signal and address signal before the actual wake-up process. The master device monitors the I2C bus for a start signal followed by an address signal matching the dormant device's address, and only then generates the wake-up signal. This preliminary detection prevents premature or incorrect wake-up attempts that could cause glitches, ensuring reliable wake-up while maintaining energy savings during dormant state.
2Productivity
If the wake-up sequence is transmitted to wake up the I2C device, then the device can be activated, but glitches occur during transmission causing wake-up failure
Solution Approach 1:
The patent implements feedback by having the master device continuously monitor the I2C bus for the start signal and address signal sequence before initiating the wake-up process. This feedback mechanism ensures that the wake-up signal is only generated when the correct conditions are met (start signal followed by matching address signal), preventing glitches caused by incorrect or premature wake-up attempts. The feedback loop verifies the wake-up sequence integrity before execution.
3Reliability
If power off or restart is used to recover normal operation after glitch, then the device can resume operation, but wake-up efficiency is significantly reduced
Solution Approach 1:
The patent eliminates the need for power off or restart by implementing preliminary detection of the start signal and address signal. The master device monitors these signals and generates the wake-up signal only when the correct sequence is detected, allowing the dormant device to wake up normally without requiring full power cycle recovery. This preliminary action prevents glitches before they occur, maintaining both reliability and efficiency.
Data Source
AI summary
A method and circuit for waking up an I2C device are disclosed. The method includes determining whether a start signal is received; determining whether a next signal immediately received after the start signal is an address signal when the start signal is received; matching the next signal immediately received after the start signal with an address of the I2C device when the next signal is the address signal; and generating a wake-up signal to wake up the I2C device when the next signal immediately received after the start signal is matched with the address of the I2C device.