MEMS Sensor Readout Circuit With Boosted Output Amplifier Supply
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Solution Overview
Problem
MEMS sensors in mobile devices face challenges in reducing energy consumption while maintaining performance, particularly when decreasing the supply voltage affects the dynamic range and noise properties of analog signal paths.
Innovation Solution
The readout circuit for MEMS sensors employs a cascade circuit with an input amplifier operated at a supply voltage less than or equal to the external voltage and an output amplifier operated at a higher supply voltage, achieved through step-up conversion, to maintain dynamic range and optimize energy consumption.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Use of energy by moving object
If the supply voltage of the sensor ASIC is decreased to save energy, then energy consumption is reduced, but performance deteriorates due to decreased dynamic range and degraded noise properties in the analog signal path
Solution Approach 1:
The patent applies local quality by providing different supply voltages to different parts of the readout circuit. Specifically, the input amplifier receives a first supply voltage (lower or equal to external supply voltage) while the output amplifier receives a second supply voltage (higher than external supply voltage) through a step-up converter. This localized voltage differentiation allows the output stage to maintain high dynamic range and low noise performance while the overall system operates at lower external supply voltage for energy savings.
2Use of energy by moving object
If the external supply voltage is reduced to optimize energy consumption, then energy efficiency improves, but the dynamic range of circuit components in the analog signal path deteriorates
Solution Approach 1:
The patent introduces a step-up converter as an intermediary component between the external supply voltage source and the output amplifier. This intermediary circuit generates a second supply voltage that is higher than the external supply voltage, specifically for powering the output amplifier. This allows the output stage to achieve the required dynamic range despite the externally reduced supply voltage, effectively mediating between energy efficiency requirements and performance requirements.
3Use of energy by moving object
If the supply voltage of all circuit components is uniformly reduced, then energy consumption decreases, but noise properties and amplification factors of operation amplifiers deteriorate
Solution Approach 1:
The patent implements local quality by selectively applying different supply voltages to different amplifiers in the readout circuit. The input amplifier operates with a first supply voltage (lower or equal to external supply voltage) while the output amplifier operates with a second supply voltage (higher than external supply voltage) generated by a step-up converter. This localized voltage optimization ensures that noise-critical output stages maintain high measurement precision while the overall system achieves reduced energy consumption.
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
This approach allows the readout circuit to operate with a lower external supply voltage without performance losses, enhancing overall performance and optimizing energy consumption by selectively increasing the supply voltage of performance-critical output amplifiers.
Implementation Method 1
a first supply voltage is present at the input amplifier, which is less than or equal to the external supply voltage. The first supply voltage preferably corresponds to the external supply voltage or is generated by step-down conversion of the external supply voltage. In contrast, a second supply voltage, which is greater than the external supply voltage, is present at the output amplifier.
Data Source
AI summary
A readout circuit for a MEMS sensor unit. The readout circuit includes at least one circuit component which includes a cascade circuit including at least one input amplifier and at least one output amplifier. A predefined external supply voltage is available for operating the readout circuit. In the process, the input amplifier is operated with a first supply voltage which is, by comparison, less than or equal to the external supply voltage, and the output amplifier is operated with a second supply voltage which is, by comparison, greater than the external supply voltage. At least one circuit means, which makes the second supply voltage is also provided, which is, by comparison, greater than the external supply voltage, available to the output amplifier.