Motor Controller Temporary Current Boost for Image Stabilization
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Solution Overview
Problem
Conventional motor controllers cannot temporarily supply a driving current greater than the maximum rated current to a motor coil, which can lead to damage when higher currents are needed for applications like image stabilization in camera modules.
Innovation Solution
A motor controller comprising a driving circuit, control unit, digital-to-analog converter, operational amplifier, switch circuit, and resistor, which allows for temporary increase of driving current by adjusting voltage and current through transistors and resistors, enabling currents up to twice the maximum rated current when necessary.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Speed
If the driving current is increased beyond the maximum rated current to improve motor response speed and positioning accuracy, then the settling time decreases and image stabilization performance improves, but the motor coil may be damaged due to excessive current
Solution Approach 1:
The motor controller dynamically adjusts the driving current based on real-time operational needs. The control unit monitors motor position, velocity, and load conditions, then adaptively modifies the current magnitude. During normal operation, current is limited to rated values for safety. During critical phases like rapid positioning or vibration compensation, the controller temporarily increases current beyond rated levels, then returns to normal levels, creating a dynamic current profile that optimizes both performance and reliability
Solution Approach 2:
The system employs periodic pulse-width modulation (PWM) to deliver high current in controlled bursts rather than continuous operation. The controller applies short-duration current pulses at optimized intervals during motor acceleration, deceleration, or vibration correction phases. This periodic high-current delivery achieves the necessary torque and response speed while allowing the motor coil to cool and recover between pulses, preventing thermal damage
Solution Approach 3:
The control algorithm predicts upcoming high-demand phases and pre-adjusts current levels in advance. When the motor controller detects that a rapid positioning maneuver or vibration correction is about to occur based on target position calculations or vibration sensor input, it proactively increases current before the actual high-torque phase begins. This preliminary current increase ensures immediate motor response without exceeding safety limits during the transition phases
2Reliability
If the driving current is limited to the maximum rated current to ensure motor safety, then the motor coil is protected from damage, but the settling time increases and the motor cannot respond quickly enough for image stabilization
Solution Approach 1:
The controller changes the electrical parameters (current magnitude, voltage level, frequency) based on the motor's operational state and the specific task requirements. For rapid positioning, the controller temporarily modifies parameters to allow higher current flow. For normal operation, parameters are maintained at rated values. This dynamic parameter adjustment enables the system to achieve fast settling times when needed while maintaining motor safety during extended operation
Solution Approach 2:
The system applies partial high-current action only during the specific time intervals and operational phases where maximum performance is critical, such as the final approach to target position or during detected vibration events. The excessive current is applied briefly and selectively rather than continuously, achieving the necessary performance boost without subjecting the motor coil to sustained stress that would cause damage
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
Enables faster motor positioning and image stabilization by temporarily increasing driving current, preventing motor damage while maintaining practical effectiveness.
Implementation Method 1
a digital-to-analog converter receives a control signal and a digital input data for generating a voltage to an operational amplifier
Implementation Method 2
an operational amplifier, a switch circuit, and a resistor. The digital-to-analog converter receives a control signal and a digital input data for generating a voltage to the operational amplifier
Implementation Method 3
A motor controller comprising a driving circuit, a control unit, a digital-to-analog converter, an operational amplifier, a switch circuit, and a resistor
Implementation Method 4
The motor has a motor coil and a maximum rated current... enabling faster motor positioning and image stabilization by temporarily increasing driving current
Data Source
AI summary
A motor controller used for driving a motor is provided. The motor includes a motor coil and a maximum rated current. The motor controller comprises a driving circuit, a control unit, a digital-to-analog converter, an operational amplifier, a switch circuit, and a resistor. When it is needed to decrease a settling time for the motor to reach a target position, or a vibration is detected within a camera module so as to enable an image stabilization mechanism, it is capable of temporarily supplying a driving current greater than the maximum rated current to the motor coil.