Hall Sensor Amplifier Gain Compensation for Stress-Stable Detection
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Solution Overview
Problem
Existing semiconductor devices face challenges in reducing stress dependence of physical quantity sensor sensitivity, leading to inaccurate detection and increased current consumption, due to limitations in piezoelectric coefficient compensation and excessive compensation methods that can reverse or increase stress dependence.
Innovation Solution
A semiconductor device with a voltage divider circuit and transimpedance amplifier configuration, utilizing first and second resistor circuits with different piezoelectric coefficients, and transconductance amplifiers to adjust the gain and minimize stress dependence, while maintaining a small circuit area and low current consumption.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If a conventional amplifier configuration is used, then the circuit area and current consumption are small, but the stress dependence of sensor sensitivity cannot be appropriately compensated
Solution Approach 1:
The amplifier is divided into multiple stages: a first amplifier stage that provides voltage gain and a second amplifier stage that provides current gain. This segmentation allows independent optimization of each stage for different functions, enabling effective stress dependence compensation without requiring a completely complex circuit architecture.
Solution Approach 2:
The patent introduces a variable gain configuration where the gain of the amplifier stages can be adjusted based on stress conditions. By dynamically adjusting the gain parameters of the first and second amplifier stages, the system can adaptively compensate for stress-induced sensitivity changes while maintaining circuit simplicity.
2Measurement precision
If multiple amplifiers are arranged in multiple stages to increase compensation amount, then the desired stress dependence can be obtained, but the number of amplifiers increases and area and current consumption increase
Solution Approach 1:
The patent combines voltage amplification and current amplification functions into a single integrated amplifier circuit with two stages. The first stage performs voltage gain while the second stage performs current gain, merging multiple functions into one compact unit that achieves high compensation effectiveness without increasing component count or power consumption.
Solution Approach 2:
The multi-stage amplifier is designed to perform multiple functions: voltage amplification, current amplification, and stress dependence compensation all within a single circuit block. This universal design eliminates the need for separate compensation circuits, reducing overall current consumption while maintaining high measurement precision.
3Measurement precision
If the piezoelectric coefficient of the resistor is increased to enhance compensation, then the stress dependence can be sufficiently compensated, but the sign of stress dependence may be reversed and stress dependence may be increased
Solution Approach 1:
The patent employs precise parameter adjustment in the amplifier stages, specifically controlling the gain parameters and feedback ratios to achieve optimal compensation. By carefully selecting and adjusting these parameters, the system achieves sufficient stress dependence compensation while maintaining stable sign characteristics and avoiding over-compensation that would reverse the stress dependence sign.
4Measurement precision
If a simple amplifier configuration is used, then the circuit area is small, but the stress dependence of sensitivity varies and detection accuracy decreases
Solution Approach 1:
The amplifier is segmented into two functional stages within a compact layout: a voltage gain stage and a current gain stage. This segmentation enables high detection accuracy through precise signal conditioning while maintaining a small overall circuit area by integrating both stages in a unified design.
Solution Approach 2:
The patent implements a nested amplifier architecture where the second amplifier stage is effectively nested within the output path of the first stage. This nested configuration allows both voltage and current amplification functions to be packed into a minimal area, achieving high detection accuracy without increasing circuit footprint.
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
The solution enables high-accuracy physical quantity detection with reduced stress dependence and minimal circuit area and current consumption, effectively addressing the limitations of existing technologies.
Implementation Method 1
a first resistor circuit (41) having a first piezoelectric coefficient and a second resistor circuit (42) having a second piezoelectric coefficient different from the first piezoelectric coefficient
Data Source
AI summary
The semiconductor device includes a Hall element, a first differential pair, a second differential pair, an output amplifier circuit, and a voltage divider circuit. The Hall element outputs a signal that is dependent on stress to be applied to a semiconductor substrate to the first differential pair. The voltage divider circuit divides a voltage into a divided voltage having a voltage dividing ratio that is dependent on the stress. The first differential pair outputs a first current based on the signal. The second differential pair outputs a second current based on the divided voltage and a reference voltage. The output amplifier circuit outputs a voltage based on the first and second currents. A gain of the output amplifier circuit is approximated by a sum of a difference between stress dependence coefficients of transconductances of the first and second differential pairs and a stress dependence coefficient of the voltage dividing ratio.