Wakeup Detector Circuit Using Adaptive Sampling and Pulse Qualification
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Solution Overview
Problem
Wakeup circuits in electronic devices operating in low power states face challenges with unreliable detection of wakeup signals due to the use of low-frequency, unreliable clocks, such as ring oscillators, which can miss state changes or incorrectly identify bursts and spaces in input signals, leading to unreliable system operation.
Innovation Solution
A wakeup circuit design that includes a sampling circuit to synchronize and reduce the frequency of input signals, generating an activity signal with pulses for each state change, and a qualification window mechanism to declare a wakeup event based on a threshold number of pulses detected within a specified period, allowing reliable detection even with clocks of varying frequencies.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Use of energy by stationary object
If a low-frequency clock (such as ring oscillator) is used in the wakeup circuit, then power consumption is reduced and cost is lowered, but the reliability of wakeup signal detection deteriorates
Solution Approach 1:
The patent applies dynamics by making the sampling frequency adaptive rather than fixed. The sampling circuit dynamically adjusts its operation based on the detected signal characteristics, allowing the system to use lower sampling frequencies (and thus lower power) when possible, while automatically increasing frequency when signal complexity requires it. This resolves the contradiction by making power consumption dependent on actual detection needs rather than using a consistently high frequency for all conditions.
Solution Approach 2:
The patent changes the parameter of sampling frequency from a fixed high value to a variable value that can be adjusted within a range (7-29 MHz). By allowing the sampling frequency parameter to change based on signal characteristics and detection requirements, the system can operate at lower power consumption levels while maintaining detection reliability when needed. This directly addresses the contradiction by making the frequency parameter adaptive rather than static.
2Ease of manufacture
If a low-frequency clock is used, then device cost is reduced, but measurement precision of signal state changes deteriorates
Solution Approach 1:
The sampling circuit dynamically adjusts its sampling rate based on the complexity and characteristics of the input signal. For simple signals, lower sampling frequencies suffice, reducing cost. For complex signals requiring higher precision, the circuit automatically increases the sampling frequency. This dynamic adaptation resolves the contradiction between cost and precision by making precision dependent on actual signal requirements rather than using a uniformly high sampling rate.
Solution Approach 2:
The patent enables the sampling frequency parameter to change within a range (7-29 MHz) based on detection needs. This parameter change capability allows the system to use lower frequency (and thus lower cost) components while maintaining the ability to achieve high measurement precision when the signal characteristics require it. The flexible parameter approach resolves the contradiction between manufacturing cost and measurement precision.
3Adaptability or versatility
If the clock frequency is varied within a range, then adaptability of the wakeup circuit improves, but the complexity of frequency synchronization increases
Solution Approach 1:
The sampling circuit performs self-synchronization by automatically adapting to the clock frequency present in the system. Rather than requiring external configuration or complex synchronization logic, the circuit self-adjusts to operate correctly with any clock frequency within the 7-29 MHz range. This self-service approach resolves the contradiction by eliminating the need for complex synchronization mechanisms while maintaining broad frequency adaptability.
Solution Approach 2:
The wakeup circuit is designed with universal functionality to operate with any clock frequency within the specified range without requiring specific configuration. The sampling circuit serves multiple frequency standards simultaneously through its adaptive design, making the system universally compatible across different clock configurations. This multi-functionality approach resolves the contradiction between adaptability and complexity by achieving frequency independence through a single unified circuit design.
Data Source
AI summary
Systems and methods related to wakeup circuits for electronic devices are disclosed. More particularly, an electronic device includes a component operable in at least a lower power state and a higher power state and a wakeup circuit configured to signal the component to transition from the lower power state to the higher power state upon declaration of a wakeup event. The wakeup circuit is configured to process a received input signal to synchronize with a clock; generate an activity signal that includes an activity pulse for each time the processed input signal changes state in different cycles of the clock; open a qualification window upon detection of a first activity pulse in the activity signal; and in the event more than a threshold number of activity pulses in the activity signal are detected prior to closing the qualification window, declare a wakeup event.