Drive Control Circuit for Linear Vibration Motor Braking
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Solution Overview
Problem
Existing linear vibration motors face challenges in reducing vibration stoppage time due to varying brake force depending on the motor type and number of cycles, leading to inefficiencies in braking control.
Innovation Solution
A drive control circuit that includes a drive signal generating unit, a driver unit, and an induced voltage detector, which generates a drive signal with an opposite phase and high impedance period to quickly stop the motor by estimating the vibration force and controlling the drive signal based on detected induced voltage, thereby optimizing the braking process.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of operation
If a fixed frequency brake signal is applied to stop the motor, then the braking control is simple to implement, but the brake force varies depending on motor type and cycle number resulting in excess or deficiency in braking
Solution Approach 1:
The patent applies dynamics by transitioning from a fixed frequency brake signal to a variable frequency signal that adapts to the motor's actual resonance frequency. The control circuit dynamically adjusts the brake signal frequency based on detected vibration characteristics, ensuring optimal braking force across different motor types and operational cycles while maintaining reliable and consistent stopping performance.
Solution Approach 2:
The patent implements feedback by using a vibration detector to monitor the motor's vibration frequency during operation and during braking. This detected frequency information is fed back to the control circuit, which then adjusts the brake signal frequency accordingly. This closed-loop feedback mechanism ensures that the brake force remains consistent and appropriate for each specific motor type and operational state.
2Loss of time
If the brake force is increased to reduce vibration stoppage time, then the stopping speed improves, but the motor may overshoot or exhibit unstable stopping behavior
Solution Approach 1:
The patent applies dynamics by using a variable amplitude brake signal that adapts during the braking process. The control circuit adjusts the signal amplitude based on the detected vibration frequency and decay characteristics, applying stronger initial braking force to reduce stoppage time while gradually modulating the force to prevent overshoot and ensure stable stopping behavior.
Solution Approach 2:
The patent utilizes periodic action by applying brake signals that are synchronized with the motor's natural vibration frequency. By timing the brake pulses to match the vibration cycle, the system achieves efficient energy dissipation and rapid stopping while maintaining stability through resonant damping rather than forced opposition.
3Productivity
If a variable frequency drive signal is used to maintain resonance frequency, then the driving efficiency is optimized, but the control circuit complexity increases
Solution Approach 1:
The patent applies universality by designing a control circuit that performs multiple functions: it generates the drive signal, detects vibration frequency, determines resonance conditions, and generates the brake signal. This multi-functional approach consolidates what could be separate complex subsystems into a single integrated circuit, achieving optimal driving efficiency through resonance frequency maintenance while limiting the increase in overall system complexity.
Solution Approach 2:
The patent implements self-service by enabling the control circuit to automatically detect and track the motor's resonance frequency without external intervention. The vibration detector and control logic work together to autonomously adjust the drive signal frequency to maintain resonance, eliminating the need for manual tuning or complex external control systems while preserving high driving efficiency.
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
This solution effectively reduces vibration stoppage time by adapting the drive signal to the motor's resonance frequency, maintaining driving force and efficiency, and minimizing variations in motor performance across different products and over time.
Implementation Method 1
an induced voltage occurring in the coil... The induced voltage detector detects the induced voltage occurring in the coil
Implementation Method 2
having a stator and a vibrator at least one of which is constituted by an electromagnet, vibrates the vibrator relative to the stator by supplying a drive current to a coil of the electromagnet
Data Source
AI summary
In a drive control circuit of a linear vibration motor, a drive signal generating unit generates a drive signal used to alternately deliver a positive current and a negative current to a coil. A driver unit generates a drive current in response to the drive signal generated by the drive signal generating unit and supplies the drive current to the coil. An induced voltage detector detects an induced voltage occurring in the coil. After a running of the linear vibration motor has terminated, the drive signal generating unit generates a drive signal whose phase is opposite to that of the drive signal generated during the motor running; this drive signal of opposite phase includes a high impedance period during which the driver unit is controlled to a high impedance state. The induced voltage detector detects the induced voltage occurring in the coil during the high impedance period.