Shock detector circuit and method for operation thereof

Patent metadata

Field	Value
Publication number	US-10141873-B2
Application number	US-201615292694-A
Country	US
Kind code	B2
Filing date	Oct 13, 2016
Priority date	Nov 18, 2015
Publication date	Nov 27, 2018
Grant date	Nov 27, 2018

Abstract

The present invention concerns an electronic device comprising a calculation unit capable of generating a signal representative of a physical magnitude, for a motor driving a display device, said motor comprising a rotor in a magnetic circuit, two terminals, one positive and one negative, via which the calculation unit controls the motor, the electronic device further comprising at least one shock detector circuit connected between the calculation unit and a motor terminal for the detection of an external shock applied to the motor,
said motor having a first position of stable equilibrium placed at a reference angular position and a second position of stable equilibrium placed at 180° from the first stable angular position, for each direction of rotation, a maximum angular position from which it is no longer possible to return the motor rotor into a prior angular position, the calculation unit using an algorithm which, following a shock, can detect the direction of rotation of the rotor by analyzing an induced voltage detected by said detector circuit and cause to be sent a blocking pulse of reverse polarity to that of the induced voltage.

First claim

What is claimed is:

1. An electronic device comprising:
calculation circuitry configured to generate a signal representative of a physical magnitude, for a motor driving a display device, said motor comprising a rotor in a magnetic circuit, two terminals, one positive and one negative, via which the calculation circuitry controls the motor,
two shock detector circuits, each shock detector circuit being connected between the calculation circuitry and one of the two terminals for the detection of an external shock applied to the motor,
said motor having a first position of stable equilibrium placed at a reference angular position and a second position of stable equilibrium placed at 180° from the first stable angular position, for each direction of rotation, a maximum angular position from which the rotor is unable to return to a prior angular position, and
the calculation circuitry using an algorithm which, following a shock, detects the direction of rotation of the rotor by analysing an induced voltage detected by said shock detector circuit and sends a blocking pulse of reverse polarity to that of the induced voltage to stop and return the rotation,
wherein the blocking pulse has a maximum duration of 58.5 ms to stop and return the rotor to a predetermined angular position before the rotor reaches the maximum angular position.

2. The electronic device according to claim 1 , wherein the blocking pulse has a chopping rate that varies from 25% to 100% of a duty cycle of the blocking pulse.

3. The electronic device according to claim 1 , wherein the shock detector circuit comprises a sensitivity selector adjusting a detection sensitivity of the shock detector circuit.

4. The electronic device according to claim 1 , wherein the motor is arranged such that the positions of stable equilibrium of the rotor when there is no current flowing through a coil placed at an angle of 30 to 90 degrees with respect to the axis of the main flux generated by the coil in the magnetic circuit when a current passes therethrough.

5. The electronic device according to claim 1 , wherein the blocking pulse is sent to the motor via one or other of the two terminals thereof.

6. The electronic device according to claim 2 , wherein the blocking pulse comprises at least a first phase and a second phase distinct from each other, each phase including a distinct chopping rate.

7. The electronic device according to claim 3 , wherein the sensitivity selector allows for a range of the detection sensitivity from 50 millivolts to 600 millivolts.

8. The electronic device according to claim 6 , wherein the second phase has a longer duration than the first phase.

9. The electronic device according to claim 8 , wherein the second phase has a duration two times longer than the first phase.

10. An electronic device comprising:
calculation circuitry configured to generate a signal representative of a physical magnitude, for a motor driving a display device, said motor comprising a rotor in a magnetic circuit, two terminals, one positive and one negative, via which the calculation circuitry controls the motor,
two shock detector circuits, each shock detector circuit being connected between the calculation circuitry and one of the two terminals for the detection of an external shock applied to the motor,
said motor having a first position of stable equilibrium placed at a reference angular position and a second position of stable equilibrium placed at 180° from the first stable angular position, for each direction of rotation, a maximum angular position from which the rotor is unable to return to a prior angular position, and
the calculation circuitry using an algorithm which, following a shock, detects the direction of rotation of the rotor by analysing an induced voltage detected by said shock detector circuit and sends a blocking pulse of reverse polarity to that of the induced voltage to stop and return the rotation,
wherein the blocking pulse has a maximum duration of 58.5 ms to stop and return the rotor to a predetermined angular position before the rotor reaches the maximum angular position, and
wherein the blocking pulse comprises at least a first phase and a second phase distinct from each other, each phase including a distinct chopping rate, the first phase has a larger chopping rate than the second phase, and the second phase occurs after the first phase.

Assignees

• Eta Sa Mft Horlogere Suisse

Inventors

• Klopfenstein Francois
• Berthoud Joerg
• Jeannet Nicolas
• Godat Yves
• Bonnet Thierry

Classifications

• H02P8/02 Primary

  specially adapted for single-phase or bi-pole stepper motors, e.g. watch-motors, clock-motors · CPC title

• G04C3/143

  Means to reduce power consumption by reducing pulse width or amplitude and related problems, e.g. detection of unwanted or missing step · CPC title

• G01P15/0802

  Details · CPC title

• H02P29/02

  Providing protection against overload without automatic interruption of supply (protection against faults of stepper motors H02P8/36) · CPC title

• H02P6/185 Primary

  using inductance sensing, e.g. pulse excitation · CPC title