Analog Image Stabilization Circuit Phase Delay Compensation

Solution Overview

Problem

Existing image stabilization control circuits in image capturing devices face challenges with high power consumption and reduced accuracy due to phase delay issues in the gyro-equalizer, leading to inefficient camera shake compensation, especially in high-frequency regions.

Innovation Solution

The implementation of a phase delay compensation circuit within the image stabilization control circuit using a digital filter, specifically a low-boost filter, to adjust and counterbalance phase delays, allowing for accurate vibration compensation without the need for a microprocessor, thereby reducing power consumption.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Measurement precision

If a microprocessor is used to implement the gyro-equalizer with high-speed clock operation, then the processing speed and accuracy of vibration compensation is improved, but power consumption increases rapidly

Engineering Contradiction:

Improveaccuracy of vibration compensationVSAvoidpower consumption

Core Design Contradiction:

Measurement precisionVSUse of energy by moving object

Solution Approach 1:

The patent replaces the microprocessor-based digital computation system with an analog circuit system consisting of operational amplifiers, capacitors, and resistors. The integration function is implemented through analog capacitor charging/discharging circuits, and the high-pass filter is implemented through analog RC circuits. This substitution eliminates the need for high-speed clock operations while maintaining the required processing accuracy for vibration compensation.

Inventive Principle:

Principle #28Mechanics substitution (Replace mechanical system)

Solution Approach 2:

The patent creates an analog copy of the digital signal processing functions. The analog circuit replicates the mathematical operations of integration and high-pass filtering that would normally be performed by a microprocessor running at high speed. By copying the functional behavior in analog form, the system achieves the same computational results without the power consumption overhead of digital processing.

Inventive Principle:

Principle #26Copying

2Use of energy by moving object

If the gyro-equalizer is implemented with filter circuits to reduce power consumption, then microprocessor usage is eliminated and power consumption decreases, but phase delay accuracy deteriorates in high-frequency regions

Engineering Contradiction:

Improvepower consumptionVSAvoidphase delay accuracy

Core Design Contradiction:

Use of energy by moving objectVSMeasurement precision

Solution Approach 1:

The patent carefully selects and adjusts the circuit parameters (resistance values, capacitance values) of the analog high-pass filter and integration circuits to optimize phase delay characteristics. By changing these parameters, the system achieves both low power consumption and accurate phase delay compensation across the target frequency range, particularly in high-frequency regions where phase accuracy is critical for effective vibration compensation.

Inventive Principle:

Principle #35Parameter changes

Solution Approach 2:

The analog circuit incorporates feedback mechanisms through the operational amplifier configurations in both the high-pass filter and integration stages. These feedback loops enable the circuit to maintain stable operation and accurate phase delay characteristics without requiring active digital correction, thereby preserving both low power consumption and high phase delay accuracy.

Inventive Principle:

Principle #23Feedback

3Speed

If high-speed clock operation is used in the microprocessor, then the response speed to camera shake vibration is improved, but the secondary battery depletes more rapidly and drive time is reduced

Engineering Contradiction:

Improveresponse speed to vibrationVSAvoiddrive time

Core Design Contradiction:

SpeedVSDuration of action of moving object

Solution Approach 1:

The patent replaces the microprocessor-based digital computation system with an analog circuit system consisting of operational amplifiers, capacitors, and resistors. The integration function is implemented through analog capacitor charging/discharging circuits, and the high-pass filter is implemented through analog RC circuits. This substitution eliminates the need for high-speed clock operations while maintaining the required processing accuracy for vibration compensation.

Inventive Principle:

Principle #28Mechanics substitution (Replace mechanical system)

Solution Approach 2:

The patent creates an analog copy of the digital signal processing functions. The analog circuit replicates the mathematical operations of integration and high-pass filtering that would normally be performed by a microprocessor running at high speed. By copying the functional behavior in analog form, the system achieves the same computational results without the power consumption overhead of digital processing.

Inventive Principle:

Principle #26Copying

Data Source

PatentUS7760448B2Image stabilization control circuit

Publication Date: 2010.07.20 SEMICON COMPONENTS IND LLC

AI summary

A image stabilization control circuit for an image capturing device, wherein a gyro-equalizer (24) integrates an angular velocity signal from a gyro-sensor (12) in an integration circuit (46). The integration circuit (46) is composed of a low-boost filter (LBF), and a phase delay in a target compensation region is set to a value appropriate for an integration process. Furthermore, a characteristic whereby the LBF reduces the phase delay at higher frequencies is used, compensation is applied to the excess phase delay of the angular signal in the high-frequency region brought about by the effect of the phase delay generated in the high-frequency region by the output signal of the gyro-sensor (12), and the phase delay in the high-frequency region is brought nearer to 90 degrees. This allows the accuracy of the process for determining the required displacement magnitude of a lens to be increased.