Gap-closing actuator having a double-wound driving coil

Patent metadata

Field	Value
Publication number	US-11539279-B2
Application number	US-202016900744-A
Country	US
Kind code	B2
Filing date	Jun 12, 2020
Priority date	Sep 27, 2019
Publication date	Dec 27, 2022
Grant date	Dec 27, 2022

Abstract

A haptic engine includes a gap-closing actuator having a double-wound driving coil in which the two windings can be activated with two driving sources, respectively. Or, the two windings double-wound driving coil can be activated with a single driving source when the two windings are connected with each other either in series or in parallel. By using the double-wound driving coil in the gap-closing actuator as described, an instant inductance of either of the two windings can be determined without having to measure in real time a resistance of the corresponding winding.

First claim

What is claimed is:

1. A haptic engine comprising:
a frame;
a first coil and a second coil wound together around a common core, the first coil and the second coil being thermally coupled with each other and mechanically coupled with the frame, the first coil having first terminals and the second coil having second terminals;
first driver circuitry electrically coupled with the first coil at the first terminals to drive a first driving current through the first coil;
first voltage- and current-sensing circuitry electrically coupled with the first coil at the first terminals to sense a first driving voltage across, and the first driving current through, the first coil;
second driver circuitry electrically coupled with the second coil at the second terminals to drive a second driving current through the second coil, wherein
the first driving current and the second driving current have different values, and
an increase of the first current is different from a decrease of the second current;

second voltage- and current-sensing circuitry electrically coupled with the second coil at the second terminals to sense a second driving voltage across, and the second driving current through, the second coil;
an attraction plate spaced apart from the first and the second coils through a gap, the attraction plate arranged to be driven relative to the frame along a driving direction to cause variation of the gap when the first driving current is driven through the first coil, and the second driving current is driven through the second coil; and
computing circuitry configured to determine values of the gap between the attraction plate and the first and the second coils, the gap values determined
independently of resistances of either the first coil or the second coil, and
dependently of the first driving current through, and the first driving voltage across, the first coil, and the second driving current through, and the second driving voltage across, the second coil, and rates of change of the first and second driving currents.

2. The haptic engine of claim 1 , wherein to determine the gap, the computing circuitry is configured to
compute a first inductance of the first coil or a second inductance of the second coil, wherein each of the first inductance and the second inductance is computed independently of resistances of either the first coil or the second coil, and dependently of the first driving current through, and the first driving voltage over, the first coil, and the second driving current through, and the second driving voltage over, the second coil, and the rates of change of the first and second driving currents, and
invert the first inductance of the first coil, or the second inductance of the second coil.

3. The haptic engine of claim 1 , wherein the first driver circuitry and the second driver circuitry are configured to drive the first driving current through the first coil and the second driving current through the second coil with frequencies in a frequency range of 10 Hz to 5 kHz, preferably 300 Hz to 1 kHz.

4. The haptic engine of claim 1 , wherein the first driver circuitry and the second driver circuitry are synchronized to drive the first driving current through the first coil and the second driving current through the second coil with the same frequency, and
(i) when first and second coils are wound in the same direction, in phase relative to each other, or
(ii) when first and second coils are wound in opposite directions, 180° -out-of-phase relative to each other.

5. The haptic engine of claim 1 , comprising
an integrated circuit, wherein the integrated circuit comprises
the first driver circuitry comprising a first driving-current source to supply the first driving current through the first coil,
the first voltage and current sensing circuitry comprising a first voltage sensor and a first current sensor to sense respective values of the first driving voltage across, and the first driving current through, the first coil,
the second driver circuitry comprising a second driving-current source to supply the second driving current through the second coil, and
the second voltage and current sensing circuitry comprising a second voltage sensor and a second current sensor to sense respective values of the second driving voltage across, and the second driving current through, the second coil.

6. The haptic engine of claim 1 , comprising
an integrated circuit, wherein the integrated circuit comprises
the first driver circuitry comprising a first driving-voltage source to supply a first driving voltage across the first coil to induce the first driving current through the first coil,
the first voltage and current sensing circuitry comprising a first voltage sensor and a first current sensor to sense respective values of the first driving voltage across, and the first driving current through, the first coil,
the second driver circuitry comprising a second driving-voltage source to supply a second driving voltage across the second coil to induce the second driving current through the second coil, and
the second voltage and current sensing circuitry comprising a second voltage sensor and a second current sensor to sense respective values of the second driving voltage across, and the second driving current through, the second coil.

7. The haptic engine of claim 5 or 6 , wherein the computing circuitry is coupled with
the first voltage/current sensing circuitry to receive respective values of the first driving voltage across, and the first driving current through, the first coil, and
the second voltage/current sensing circuitry to receive respective values of the second driving voltage across, and the second driving current through, the second coil.

8. The haptic engine of claim 5 or 6 , wherein the integrated circuit is disposed either inside or outside the frame.

9. The haptic engine of claim 1 , wherein the computing circuitry is disposed either inside or outside the frame.

10. A method for determining inductance of each winding of a coil with two windings wound together around a common core, the method comprising:
driving a first current through a first of the two windings;
driving a second current through a second of the two windings, wherein
the second current is different than the first current, and
an increase of the first current is different from a decrease of the second current;

sensing a first voltage across, and the first current through, the first winding;
sensing a second voltage across, and the second current through, the second winding; and
computing a first inductance the first winding or a second inductance of the second winding, wherein each of the first inductance and the second inductance is computed
independently of resistances of either the first winding or the second winding, and
dependently of the first current through, and the first voltage over, the first winding, and the second current through, and the second voltage over, the second winding, and rates of change of the first and second currents.

11. The method of claim 10 , wherein
driving the first current through the first of the two windings comprises supplying the first voltage across the first winding to induce the first current through the first winding,
driving the second current through the second of the two windings comprises supplying the second voltage across the second winding to induce the second current through the second winding.

12. The method of claim 10 , wherein
driving the first current through the first of the two windings comprises supplying the first current through the first winding,
driving the second current through t

Assignees

• Apple Inc

Inventors

• Tarelli Riccardo
• Liu Yumeng

Classifications

• H02P7/02

  the DC motors being of the linear type · CPC title

• H02K33/12 Primary

  with armatures moving in alternate directions by alternate energisation of two coil systems · CPC title

• H02P2203/01

  Motor rotor position determination based on the detected or calculated phase inductance, e.g. for a Switched Reluctance Motor · CPC title

• H01F2007/1692

  Electromagnets or actuators with two coils · CPC title

• H02P25/22

  Multiple windings; Windings for more than three phases · CPC title