Linear motor driver and method for driving same

Patent metadata

Field	Value
Publication number	US-9698719-B2
Application number	US-201615225356-A
Country	US
Kind code	B2
Filing date	Aug 1, 2016
Priority date	Sep 30, 2015
Publication date	Jul 4, 2017
Grant date	Jul 4, 2017

Abstract

The present disclosure discloses a linear vibration motor driver including an amplitude and temperature testing unit, a gain controller, and a coil resistance detector and an amplifier. The amplitude and temperature testing unit receives a motor drive input signal and a feedback drive signal output by the amplifier, and outputs a corresponding estimated motor amplitude and real-time temperature according to the motor drive input signal and the feedback drive signal. The amplifier adjusts magnification, amplifies the motor drive input signal according to the magnification and outputs the feedback drive signal to drive the motor. The present disclosure can adjust the magnitude of the drive signal according to current estimated amplitude and maximum amplitude and make corresponding rectification of the amplifier magnification upon too high temperature to extend the service life of the motor.

First claim

What is claimed is:

1. A linear vibration motor driver, comprising:
an amplitude and temperature testing unit,
a gain controller,
a coil resistance detector, and
an amplifier connected in sequence; wherein
the amplitude and temperature testing unit receives a motor drive input signal and a feedback drive signal output by the amplifier, and outputs a corresponding estimated motor amplitude and real-time temperature according to the motor drive input signal and the feedback drive signal;
the gain controller receives the estimated motor amplitude and the real-time temperature, and outputs a gain control signal to the amplifier according to the ratio of the estimated amplitude to the maximum amplitude of the motor and the ratio of the real-time temperature and the maximum temperature of the motor respectively;
the coil resistance detector tests the gain control signal and acquires an AC impedance signal corresponding to the motor drive input signal, and the AC impedance signal is output through the amplifier; and
the amplifier adjusts magnification according to the gain control signal, amplifies the motor drive input signal according to the magnification and outputs the feedback drive signal to drive the motor.

2. The linear vibration motor driver as described in claim 1 , wherein the amplitude and temperature testing unit comprises a first measuring part for receiving the feedback drive signal, the feedback drive signal comprises voltage and current feedback drive signal and the AC impedance signal, the first measuring part acquires motor impedance Z according to the feedback drive signal, acquires mechanical impedance Z m in combination with the AC impedance signal, and acquires the estimated motor amplitude by employing the following conditional expression:

H
⁡

(
ω
)

=

1

j
⁢

⁢
ω
⁢

⁢

Z
e

⁢

Z
m

B
⁢

⁢
l

+

j
⁢

⁢
ω
⁢

⁢
Bl

,

⁢

Z
=

Z
e

+

(
Bl
)

2

Z
m

,

wherein, H(ω) is the estimated motor amplitude, Bl is the power coupling coefficient, Z is the motor impedance, Z m is the mechanical impedance, Z e is the coil real-time resistance value.

3. The linear vibration motor driver as described in claim 2 , wherein the amplitude and temperature testing unit comprises a second measuring part for acquiring the real-time temperature corresponding to the real-time resistance value based on the coil initial temperature, initial coil resistance value corresponding to the initial temperature and the real-time resistance value.

4. The linear vibration motor driver as described in claim 2 , wherein the amplitude and temperature testing unit comprises a temperature sensor for real-time monitoring the real-time temperature.

5. The linear vibration motor driver as described in claim 3 , wherein the gain controller comprises a first gain processor, a second gain processor and a comparative output terminal connected with the first gain processor and the second gain processor respectively; the first gain processor outputs the first gain according to the estimated motor amplitude and the maximum amplitude; the second gain processor outputs the second gain according to the real-time temperature and the maximum temperature; the comparative output terminal makes comparison between the first gain and second gain to output the gain control signal.

6. A linear motor drive method using the linear vibration motor driver described in claim 1 , comprising the steps of:
amplitude and temperature testing step: outputting corresponding estimated motor amplitude and real-time temperature according to the motor drive output signal and the feedback drive signal;
gain control step: outputting the gain control signal according to the ratio of the estimated amplitude to the maximum amplitude of the motor and the ratio of the real-time temperature to the maximum temperature of the motor respectively;
coil resistance detection step: testing the gain control signal and acquiring an AC impedance signal corresponding to the motor drive input signal, wherein the AC impedance signal is output through the feedback drive signal;
feedback output step: adjusting magnification according to the gain control signal, amplifying the motor drive input signal according to the magnification and outputting the feedback drive signal to drive the motor.

7. The linear motor drive method as described in claim 6 , wherein in the amplitude and temperature testing step, the feedback drive signal comprises a voltage and current feedback drive signal and the AC impedance signal, the estimated motor amplitude is acquired according to the following formula:

H
⁡

(
ω
)

=

1

j
⁢

⁢
ω
⁢

⁢

Z
e

⁢

Z
m

Assignees

• Ge huan
• Ye Lijian
• Zhou Rongguan
• Aac Technologies Pte Ltd

Inventors

• Ge huan
• Ye Lijian
• Zhou Rongguan

Classifications

• H02P29/64

  Controlling or determining the temperature of the winding · CPC title

• H02P29/032 Primary

  Preventing damage to the motor, e.g. setting individual current limits for different drive conditions · CPC title

• H02P25/06 Primary

  Linear motors · CPC title

• H02P25/032 Primary

  Reciprocating, oscillating or vibrating motors · CPC title