Stepper motor for use in rotary control assembly of input device
Embodiments of the subject matter described herein relates to a stepper motor for use in a rotary control assembly of an input device. The stepper motor includes a shaft; a magnet coupled to the shaft and operable to rotate with a rotation of the shaft, the magnet generating a first magnetic field; a first coil arranged on a rotational path of the magnet; and a first current source configured to supply a first current to the first coil to cause the first coil to generate a second magnetic field, a main direction of the second magnetic field being substantially parallel with a main direction of the first magnetic field while the magnet rotates and passes the first coil.
1. A stepper motor for use in a rotary control assembly, comprising:
a shaft;
a magnet coupled to the shaft and operable to rotate with a rotation of the shaft, the magnet generating a first magnetic field;
a first coil arranged on a rotational path of the magnet, wherein the first coil is arranged to generate a first electrical signal while the magnet rotates and passes the first coil;
a first current source configured to supply a first current to the first coil to cause the first coil to generate a second magnetic field, a main direction of the second magnetic field being substantially parallel with a main direction of the first magnetic field while the magnet rotates and passes the first coil;
a first amplifier coupled to the first coil and configured to amplify the first electrical signal;
a first filter coupled between the first current source and the first amplifier and configured to eliminate a DC component
a second coil arranged on the rotational path of the magnet, wherein the second coil arranged to generate a second electrical signal while the magnet rotates and passes the second coil; and
a second amplifier coupled to the second coil and configured to amplify the second electrical signal;
wherein:
the second electrical signal and the first electrical signal having a phase difference of approximately 90 degrees, and
the second electrical signal and the first electrical signal together indicating at least one of rotational direction and a number of steps in the rotational direction of the magnet in the stepper motor.
2. The stepper motor of claim 1 , wherein the first current source is configured to supply the first current with a predefined pattern, the pattern specifying at least one of an intensity and a duration of the first current.
3. The stepper motor of claim 1 , wherein the first current source is a DC current source configured to supply a DC current.
4. The stepper motor of claim 1 , further comprising:
a second current source configured to supply a second current to the second coil to cause the second coil to generate a third magnetic field, a main direction of the third magnetic field being substantially parallel with a main direction of the first magnetic field while the magnet rotates and passes the second coil.
5. The stepper motor of claim 4 , further comprising:
a second filter coupled between the second current source and the second amplifier and configured to remove the DC component.
6. A rotary control assembly for use in an input device, comprising:
a rotating part;
a shaft;
a magnet coupled to the rotating part via the shaft and operable to rotate with a rotation of the shaft, the magnet generating a first magnetic field;
a first coil arranged on a rotational path of the magnet, wherein the first coil is arranged to generate a first electrical signal while the magnet rotates and passes the first coil;
a first current source configured to supply a first current to the first coil to cause the first coil to generate a second magnetic field, a main direction of the second magnetic field being substantially parallel with a main direction of the first magnetic field while the magnet rotates and passes the first coil;
a first amplifier coupled to the first coil and configured to amplify the first electrical signal;
a first filter coupled between the first current source and the first amplifier and configured to eliminate a DC component
a second coil arranged on the rotational path of the magnet, wherein the second coil arranged to generate a second electrical signal while the magnet rotates and passes the second coil; and
a second amplifier coupled to the second coil and configured to amplify the second electrical signal;
wherein:
the second electrical signal and the first electrical signal having a phase difference of approximately 90 degrees, and
the second electrical signal and the first electrical signal together indicating at least one of rotational direction and a number of steps in the rotational direction of the magnet.
7. The rotary control assembly of claim 6 , wherein the first current source is a DC current source configured to supply a DC current.
8. The rotary control assembly of claim 6 , further comprising:
a second current source configured to supply a second current to the second coil to cause the second coil to generate a third magnetic field, a main direction of the third magnetic field being substantially parallel with a main direction of the first magnetic field while the magnet rotates and passes the second coil.
9. The rotary control assembly of claim 8 , further comprising:
a second filter coupled between the second current source and the second amplifier and configured to remove the DC component.
10. A method of manufacturing a stepper motor, comprising:
providing a shaft;
coupling a magnet for generating a first magnetic field to the shaft in such a way that the magnet rotates with a rotation of the shaft;
arranging a first coil on a rotational path of the magnet, wherein the first coil is arranged to generate a first electrical signal while the magnet rotates and passes the first coil;
arranging a second coil on the rotational path of the magnet, wherein the second coil arranged to generate a second electrical signal while the magnet rotates and passes the second coil; and
providing:
a first current source configured to supply a first current to the first coil to cause the first coil to generate a second magnetic field, a main direction of the second magnetic field being substantially parallel with a main direction of the first magnetic field while the magnet rotates and passes the first coil;
a first amplifier coupled to the first coil and configured to amplify the first electrical signal;
a first filter coupled between the first current source and the first amplifier and configured to eliminate a DC component and
a second amplifier coupled to the second coil and configured to amplify the second electrical signal;
wherein:
the second electrical signal and the first electrical signal having a phase difference of approximately 90 degrees; and
the second electrical signal and the first electrical signal together indicating at least one of rotational direction and a number of steps in the rotational direction of the magnet in the stepper motor.