Linear Vibration Motor Drive Circuit for Fast Stoppage
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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 for linear vibration motors that includes a drive signal generating unit, a driver unit, an induced voltage detector, and a comparator to detect zero crossings and adjust the drive signal phase to opposite phase during high impedance periods, allowing for precise control of the motor's stoppage by detecting induced voltage and maintaining optimal resonance frequency.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Loss of time
If braking control is applied with fixed frequency, then vibration stoppage time can be reduced, but brake force varies depending on motor type and cycle number leading to excess or deficiency
Solution Approach 1:
The patent applies dynamics by making the braking control frequency variable rather than fixed. The drive signal generating unit dynamically adjusts the frequency of the opposite-phase drive signal based on detected vibration state, ensuring optimal braking effectiveness across different motor types and operational cycles. This resolves the contradiction by adapting the braking frequency to match the actual vibration characteristics, preventing both excess and deficiency in brake force.
Solution Approach 2:
The patent implements feedback by using the induced voltage detector to monitor the vibration motor's operational state and feed this information back to the drive signal generating unit. This closed-loop control enables real-time adjustment of the braking frequency based on actual vibration amplitude and frequency, ensuring consistent brake force application regardless of motor type or cycle number, thereby resolving the reliability issue while maintaining reduced stoppage time.
2Productivity
If drive signal frequency is adjusted to maintain resonance, then motor efficiency is improved, but complexity of control increases
Solution Approach 1:
The patent applies self-service by enabling the vibration motor system to automatically maintain its own resonance frequency through self-monitoring and self-adjustment. The induced voltage detector continuously monitors the motor's operational characteristics, and the drive signal generating unit automatically adjusts the drive frequency to match the detected resonance frequency. This self-regulating mechanism improves motor efficiency while minimizing control complexity by eliminating the need for external frequency adjustment mechanisms.
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 reduces vibration stoppage time by ensuring consistent braking force and maintaining the motor's efficiency by continuously driving the motor at its resonance frequency, minimizing the impact of variations in eigen frequencies and spring properties over time.
Implementation Method 1
an induced voltage occurring in the coil
Data Source
AI summary
In a drive control circuit of a linear vibration motor, the drive signal generating unit generates a drive signal whose phase is opposite to that of the drive signal generated during the motor running, after the running of the linear vibration motor has terminated; this drive signal of opposite phase includes a high impedance period during which the driver unit is controlled to a high impedance state. An induced voltage detector detects an induced voltage occurring in the coil. A comparator has a function as a hysteresis comparator in which the output level does not vary in a predetermined dead band, and the comparator outputs a high-level signal or a low-level signal during the high impedance period. When an in-phase signal is consecutively outputted from the comparator during the consecutive high-impedance periods, the drive signal generating unit determines that the linear vibration motor has come to a stop.