Linear vibration motor and method for controlling vibration thereof

A linear vibration motor, including:

• a vibration system that includes a driven member which is mounted to a magnetic member for reciprocating movement, wherein an amplitude of the reciprocating movement varies as an inverse function of load on the motor;
• an electromagnetic driver that includes a coil and which drives the vibration system by applying an electromagnetic force to the magnetic member, the electromagnetic force being produced by a driving current flowing through the coil;
• a detection system which detects at least one characteristic of the vibration system that is related to a characteristic frequency of the vibration system, and which produces a feedback signal indicative of a value of the at least one characteristic;
• and
• a control system which is responsive to the feedback signal, during a primary mode of operation, to controllably vary the driving current flowing through the coil in such a manner as to drive the vibration system in resonance with the characteristic frequency, and which determines the existence of a condition that renders the detection system non-functional, and drives the vibration system at a prescribed frequency when it is determined that the condition exists, during a back-up mode of operation.

A linear vibration motor, including:

• a vibration system that includes a driven member which is mounted to a magnetic member for reciprocating movement, wherein an amplitude of the reciprocating movement varies as an inverse function of load on the motor;
• electromagnetic driver means for driving the vibration system by applying an electromagnetic force to the magnetic member, the electromagnetic driver means including a coil and the electromagnetic force being produced by a driving current flowing through the coil;
• detection means for detecting at least one characteristic of the vibration system that is related to a characteristic frequency of the vibration system, and which produces a feedback signal indicative of a value of the at least one characteristic;
• and,
• control means responsive to the feedback signal, during a primary mode of operation, for controllably varying the driving current flowing through the coil in such a manner as to drive the vibration system in resonance with the characteristic frequency, and for determining the existence of a condition that renders the detection system non-functional, and driving the vibration system at a prescribed frequency when it is determined that the condition exists, during a back-up mode of operation.