Hall Sensor Common-Mode Voltage Control for OIS Position Accuracy
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Solution Overview
Problem
The accuracy of optical image stabilization in camera modules is limited by the variability in common mode voltage of hall sensors, which affects the correspondence between output voltage and position information, leading to degraded detection accuracy due to changes in temperature and bias current.
Innovation Solution
An apparatus with a bias provider and voltage regulators that adjust the voltage differences between the hall sensor and bias provider, and between the hall sensor and ground, to maintain the common mode voltage close to a reference voltage, thereby improving detection accuracy by amplifying and controlling the voltage differences using resistors and amplifiers.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If the common mode voltage of the hall sensor is not adjusted, then the device complexity is reduced, but the measurement precision of position information degrades due to temperature and bias current variations
Solution Approach 1:
The patent adjusts the common mode voltage parameter of the hall sensor by varying the voltage differences (V1 and V2) in response to temperature and bias current changes. This dynamic parameter adjustment compensates for environmental variations and maintains accurate position detection without requiring complete system redesign
Solution Approach 2:
The patent introduces voltage regulators as intermediary components between the power supply and the hall sensor. These regulators act as mediators that isolate the hall sensor from direct power supply variations and temperature effects, providing stable operating conditions and improving measurement precision
2Measurement precision
If voltage regulators are added to adjust common mode voltage, then the measurement precision improves, but the device complexity increases
Solution Approach 1:
The patent implements a feedback mechanism where the controller monitors temperature and bias current conditions and dynamically adjusts the voltage differences V1 and V2 accordingly. This closed-loop feedback system automatically compensates for environmental variations, maintaining high measurement precision without manual intervention
Solution Approach 2:
The patent transitions from static voltage regulation to dynamic voltage regulation by making the voltage differences V1 and V2 variable based on real-time temperature and bias current conditions. This dynamic adaptation allows the system to maintain optimal performance across varying operating conditions without requiring multiple fixed configurations
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 apparatus enhances the detection accuracy of magnetic flux by maintaining the common mode voltage close to the reference, improving the correlation between voltage differences and bias current, and optimizing the amplifier's output voltage range and efficiency.
Implementation Method 1
a hall sensor configured to determine a voltage difference between first and second hall sensor output terminals based on a position of the lens module
Data Source
AI summary
An apparatus with hall sensor common mode voltage adjustment includes: a bias provider configured to provide a bias current to the hall sensor; a first voltage regulator configured to vary a first voltage difference between the hall sensor and the bias provider, based on the bias current; and a second voltage regulator configured to vary a second voltage difference between the hall sensor and a ground, based on the bias current. The first and second voltage differences are variable such that a difference between the first voltage difference and the second voltage difference corresponds to a difference between a common mode voltage of first and second hall sensor output terminals of the hall sensor and a reference voltage.