Wake-Up Detector Circuit for Low-Power Radio Monitoring
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Solution Overview
Problem
In communication systems, powering down circuitry when not in use conserves battery power but requires monitoring circuitry that continues to consume power, necessitating low-power monitoring solutions to determine when to power up.
Innovation Solution
A wake-up circuit comprising comparators, an exclusive OR gate, and a tunable charge pump is used to convert signals into a direct current value, allowing for efficient wake-up of monitored circuitry with minimal power consumption.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Use of energy by moving object
If monitoring circuitry is used to determine when to power up powered down circuitry, then the circuitry can be powered down to conserve battery power, but the monitoring circuitry continues to consume power
Solution Approach 1:
The monitoring function is segmented into two parts: a simple voltage detection circuit that remains active with minimal power consumption, and the main radio circuitry that is fully powered down. This segmentation allows the system to maintain wake-up capability while minimizing monitoring power consumption.
Solution Approach 2:
A charge pump circuit acts as an intermediary between the powered-down radio module and the power source. It accumulates energy from the power bus during voltage transitions and releases it to trigger wake-up, eliminating the need for continuous power consumption by monitoring circuitry.
2Use of energy by moving object
If the radio module is completely powered down to conserve battery power, then battery life is extended, but the ability to detect wake-up signals is lost
Solution Approach 1:
The system performs preliminary action by detecting voltage transitions on the power bus before the radio module needs to wake up. The charge pump begins accumulating energy during these transitions, so when a wake-up signal is needed, the energy is already stored and ready to trigger immediate wake-up, maintaining reliable detection capability.
Solution Approach 2:
The power bus voltage transitions themselves serve as the wake-up trigger. The system uses the existing power bus activity to both power the module during operation and to trigger wake-up during power-down, eliminating the need for separate wake-up signaling circuitry.
3Use of energy by moving object
If monitoring circuitry is simplified to reduce power consumption, then battery power is conserved, but measurement precision of wake-up signals may deteriorate
Solution Approach 1:
The system changes the detection parameter from measuring subtle signal characteristics to detecting voltage transitions on the power bus. This parameter change allows for extremely simple detection circuitry with minimal power consumption while maintaining high precision, as voltage transitions are large, clear events that are easy to detect accurately.
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
Enables almost complete power down of radio modules with low-power wake-up detection, reducing overall power consumption and extending battery life without the need for additional circuitry or external power switches.
Implementation Method 1
a tunable charge pump coupled to an output of the exclusive OR gate and configured to convert a signal from the exclusive OR gate to a direct current (DC) value to wake up a circuit being monitored
Data Source
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AI summary
The apparatus is a wake-up circuit including a first comparator coupled to an input signal and configured to compare the input signal to a first comparison value. The wake-up circuit includes a second comparator coupled to the input signal and configured to compare the input signal to a second comparison value. The wake-up circuit further includes an exclusive OR gate. A first input of the exclusive OR gate is coupled to an output of the first comparator. A second input of the exclusive OR gate is coupled to an output of the second comparator. The wake-up circuit also includes a tunable charge pump coupled to an output of the exclusive OR gate and configured to convert a signal from the exclusive OR gate to a DC value to wake up a circuit being monitored.