Hall Sensor DC Offset Cancellation for OIS
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Solution Overview
Problem
High-pixel camera modules in mobile devices face image deterioration due to limited space, leading to small lens apertures and image pixel sizes, along with external vibrations and hand-shake, which cause DC offset malfunctions in optical image stabilization devices.
Innovation Solution
A hall sensor device with an amplifier and current supplier that provides compensation currents to feedback lines to cancel DC offsets in detection signals, ensuring effective hand-shake correction by amplifying signals and reducing noise levels.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If the output signal of the hall sensor is amplified, then the hand-shake detection sensitivity is improved, but a DC offset occurs causing malfunctioning of the OIS device
Solution Approach 1:
The patent implements a feedback mechanism where the amplifier output is fed back through a feedback line to a current supplier. The current supplier generates a compensation current based on the feedback signal that cancels the DC offset, allowing the amplifier to operate with high gain without causing malfunctioning.
Solution Approach 2:
The patent introduces a current supplier as an intermediary component between the amplifier and the rest of the system. This intermediary generates compensation current to cancel DC offset, enabling the amplifier to maintain high sensitivity while preventing reliability issues.
2Reliability
If a high pass filter is used to cancel DC offset in gyro sensor signal, then the DC offset is removed, but the hand-shake frequency components may be affected
Solution Approach 1:
The patent changes the approach from frequency-based filtering to DC-specific compensation. By using a feedback mechanism that targets only the DC component through the current supplier, the system removes DC offset without affecting the hand-shake frequency components that pass through the amplifier.
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 effectively cancels DC offsets across a wide frequency range at low noise levels, enhancing image stabilization and reducing image deterioration in mobile devices.
Implementation Method 1
The OIS device may use a hall sensor to detect positions of a lens on an X axis and a Y axis
Implementation Method 2
an amplifier configured to amplify a detection signal of a hall sensor
Implementation Method 3
a current supplier configured to provide a compensation current to a feedback line of the amplifier according to an offset of the detection signal, to cancel the offset
Data Source
AI summary
A hall sensor device includes: an amplifier configured to amplify a detection signal of a hall sensor; and a current supplier configured to provide a compensation current to a feedback line of the amplifier according to an offset of the detection signal, to cancel the offset.