US6351089B1
Expired / Lapsed
US
⏱️ 0.0 years remaining
Control system for a linear vibration motor
Assignee: Panasonic Electric Works Co Ltd
•
Filing: 2000-06-22
•
Granted: 2002-02-26
•
Expires: 2020-06-22
Abstract
Abstract A control system for a linear vibration motor capable of eliminating necessity of a separate sensor of detecting the motion of the motor. The linear vibration motor includes a stator provided with a winding, and a vibrator provided with a permanent magnet. The winding is fed with a drive current to generate a magnetic field which interacts with the permanent magnet to cause the vibrator to reciprocate linearly relative to the stator for producing a vibration. The control system includes a controller which detects an ongoing amplitude, i.e., the motion represented by the displacement, speed, or acceleration of the vibrator and provides ON-periods of feeding the driving current to the winding in a varying amount based upon the ongoing amplitude detected in order to keep a vibration amplitude of the vibrator constant. The controller is characterized to provide OFF-period in which the controller instructs not to feed the drive current and in which the controller detects a voltage developed across the winding and determines the ongoing amplitude based upon the detected voltage. Thus, the winding can be best utilized commonly to drive the motor and to sense the ongoing amplitude or motion of the vibrator, thereby eliminating an additional sensor for detection of the motion of the vibrator.
Inventors
- 👤 Yasuo Ibuki
- 👤 Hidetoshi Amaya
- 👤 Toyokatsu Okamoto
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-02 15:23
CPC Classifications
H; H02; H02P; H02P25/00; H02P25/02; H02P25/032
Claims Analysis
Total Claims: 12
Claim 1
Independent Claim
157 words
A control system for a linear vibration motor, said linear vibration motor comprising: a stator provided with one of a permanent magnet and a winding; a vibrator provided with the other of said permanent magnet and said winding, and said winding being fed with a drive current to generate a magnetic field which interacts with said permanent magnet to cause said vibrator to reciprocate linearly relative to said stator for producing a vibration; said control system including: a controller which detects an ongoing amplitude of said vibrator and provides ON-periods of feeding said driving current to said winding in a varying amount based upon the ongoing amplitude detected in order to keep a vibration amplitude of said vibrator constant; wherein said controller provides OFF-periods in which said controller instructs not to feed said driving current and in which said controller detects a voltage developed across said winding and determines said the ongoing amplitude based upon said voltage.
Claim 2
Dependent Claim
157 words
A control system for a linear vibration motor, said linear vibration motor comprising: a stator provided with one of a permanent magnet and a winding; a vibrator provided with the other of said permanent magnet and said winding, and said winding being fed with a drive current to generate a magnetic field which interacts with said permanent magnet to cause said vibrator to reciprocate linearly relative to said stator for producing a vibration; said control system including: a controller which detects an ongoing amplitude of said vibrator and provides ON-periods of feeding said driving current to said winding in a varying amount based upon the ongoing amplitude detected in order to keep a vibration amplitude of said vibrator constant; wherein said controller provides OFF-periods in which said controller instructs not to feed said driving current and in which said controller detects a voltage developed across said winding and determines said the ongoing amplitude based upon said voltage.
Claim 3
Dependent Claim
103 words
The control system as set forth in claim 1 , wherein said vibrator vibrates at substantially a fixed frequency, said controller providing a first OFF-period which is set to continue for a predetermined duration within which said vibrator is expected to reach a maximum displacement, said controller determining a reference time within said first OFF-period when the voltage across said winding becomes zero as indicative of that said vibrator reaches the maximum displacement, said controller determining a subsequent ON-period after a first predetermined time interval from said reference time, and determining a subsequent OFF-period after a second time interval from said reference time.
Claim 4
Dependent Claim
41 words
The control system as set forth in claim 2 , wherein said controller reads the voltage across said winding at a detection timing after a predetermined time from said reference time so as to determine said ongoing amplitude of said vibrator.
Claim 5
Dependent Claim
67 words
The control system as set forth in claim 1 , wherein said controller detects a time difference within said OFF-period between a first timing at which said voltage reaches a first reference voltage and a second timing at which said voltage reaches a second reference voltage which is different from said first reference voltage, said controller determining the ongoing amplitude of said vibrator from said time difference.
Claim 6
Dependent Claim
29 words
The control system as set forth in claim 4 , wherein said first reference voltage is zero so that said controller determines said first timing as said reference time.
Claim 7
Dependent Claim
80 words
The control system as set forth in claim 2 , wherein said controller detects a voltage difference between a first voltage of said winding detected at a first predetermined time from said reference time and a second voltage of said winding detected at a second predetermined time from said reference time, said first and second predetermined times being within said OFF-period and different from each other, and said controller determining the ongoing amplitude of said vibrator from said voltage difference.
Claim 8
Dependent Claim
21 words
The control system as set forth in claim 1 , wherein said OFF-period is defined within each cycle of said vibration.
Claim 9
Dependent Claim
27 words
The control system as set forth in claim 1 , wherein said OFF-period is defined to appear only once within more than one cycle of said vibration.
Claim 10
Dependent Claim
46 words
The control system as set forth in claim 1 , wherein said controller is responsible for feeding said drive current in the form of a pulse-width-modulated (PWM) signal during said ON-period having a correspondingly variable width, and said ON-period is limited to have a maximum width.
Claim 11
Dependent Claim
98 words
The control system as set forth in claim 1 , wherein said controller is responsible for feeding said drive current partly in the form of a pulse-width-modulated (PWM) signal during a first ON-period of variable width and the rest in the form of a fixed width signal during a second ON-period of fixed width, said first ON-period occurring in a half cycle of a particular cycle of said vibration, and said second ON-period occurring in the other half cycle of said particular cycle so that said OFF-period occurs together with said second ON-period within said other half cycle.
Claim 12
Dependent Claim
78 words
The control system as set forth in claim 1 , wherein said controller includes a low amplitude compensator which monitors the ongoing amplitude of said vibration and issues a restriction signal when said ongoing amplitude is lower than a minimum reference amplitude, said restriction signal disabling to provide said OFF-period and at the same time elongating the ON-period to feed said drive current to a maximum extent over the following over the following predetermined cycles of said vibration.
References Cited (Backward Citations)
JPS4977116A
Cited
JPS62285655A
Cited
JPS63314191A
Cited
US5202612A
Cited
US5837885A
Cited
US5632087A
Cited
US5866998A
Cited
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 2005-02-25 | 2005-08-27 | 2006-02-26 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 2009-02-25 | 2009-08-27 | 2010-02-26 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 2013-02-25 | 2013-08-27 | 2014-02-26 | $7700.00 | Window Closed / Lapsed |