Stepper motor driver circuit

Patent metadata

Field	Value
Publication number	US-2016352271-A1
Application number	US-201615155404-A
Country	US
Kind code	A1
Filing date	May 16, 2016
Priority date	May 25, 2015
Publication date	Dec 1, 2016
Grant date	—

Abstract

The stepper motor driver circuit controls driving of a stepper motor. The stepper motor driver circuit generates a driving current having a pseudo-sinusoidal waveform that varies stepwise every one period of a reference clock signal and makes the waveform of the driving current vary in response to a measurement value of an exciting voltage on a coil of the stepper motor at a time when the driving current is zero.

First claim

What is claimed is:

1 . A stepper motor driver circuit that controls driving of a stepper motor,
wherein the stepper motor driver circuit generates a driving current having a pseudo-sinusoidal waveform that varies stepwise every one period of a reference clock signal and makes the waveform of the driving current vary in response to a measurement value of an exciting voltage on a coil of the stepper motor at a time when the driving current is zero.

2 . The stepper motor driver circuit according to claim 1 , comprising:
a current control circuit that supplies the driving current having the pseudo-sinusoidal waveform that varies stepwise every one period of the reference clock signal to the coil of the stepper motor; and a comparator that compares the exciting voltage of the coil at the time when the driving current is zero and a threshold and outputs a comparison result signal.

3 . The stepper motor driver circuit according to claim 2 , wherein the current control circuit
controls the driving current to increase an average value of an absolute value of the driving current in a case where the comparison result signal indicates that the measurement value is equal to or greater than the threshold.

4 . The stepper motor driver circuit according to claim 2 , wherein the current control circuit
controls the driving current to make the pseudo-sinusoidal waveform of the driving current closer to a sinusoidal waveform in a case where the comparison result signal indicates that the measurement value is smaller than the threshold.

5 . The stepper motor driver circuit according to claim 3 , wherein the current control circuit
controls the driving current to make the pseudo-sinusoidal waveform of the driving current closer to a sinusoidal waveform in a case where the comparison result signal indicates that the measurement value is smaller than the threshold.

6 . The stepper motor driver circuit according to claim 2 , wherein the current control circuit
controls the driving current to make the pseudo-sinusoidal waveform of the driving current closer to a sinusoidal waveform in a case where a phase of an induced voltage of the coil is advanced with respect to a desired phase.

7 . The stepper motor driver circuit according to claim 3 , wherein the current control circuit
controls the driving current to increase the average value of the absolute value of the driving current in a case where a phase of an induced voltage of the coil is lagged with respect to a desired phase.

8 . The stepper motor driver circuit according to claim 6 , wherein the desired phase is a phase of the exciting voltage on the coil at a time when a torque of the stepper motor is at a desired value.

9 . The stepper motor driver circuit according to claim 6 , wherein the current control circuit
makes the driving current vary in a period shorter than the period of the reference clock signal to make the pseudo-sinusoidal waveform of the driving current closer to a sinusoidal waveform.

10 . The stepper motor driver circuit according to claim 7 , wherein the current control circuit
controls the driving current to make the pseudo-sinusoidal waveform of the driving current closer to a rectangular waveform.

11 . The stepper motor driver circuit according to claim 2 , further comprising a logic circuit that outputs a control signal based on the reference clock signal and the command signal input from the outside,
wherein the current control circuit controls the driving current in response to the control signal.

12 . The stepper motor driver circuit according to claim 6 , wherein the current control circuit
controls the driving current to increase an average value of an absolute value of the driving current in a case where the comparison result signal indicates that the measurement value is equal to or greater than the threshold.

13 . The stepper motor driver circuit according to claim 4 , wherein the current control circuit
controls the driving current to make the pseudo-sinusoidal waveform of the driving current closer to a sinusoidal waveform in a case where a phase of an induced voltage of the coil is advanced with respect to a desired phase.

14 . The stepper motor driver circuit according to claim 5 , wherein the current control circuit
controls the driving current to increase the average value of the absolute value of the driving current in a case where a phase of an induced voltage of the coil is lagged with respect to a desired phase.

15 . The stepper motor driver circuit according to claim 3 , further comprising a logic circuit that outputs a control signal based on the reference clock signal and the command signal input from the outside,
wherein the current control circuit controls the driving current in response to the control signal.

16 . The stepper motor driver circuit according to claim 4 , further comprising a logic circuit that outputs a control signal based on the reference clock signal and the command signal input from the outside,
wherein the current control circuit controls the driving current in response to the control signal.

17 . The stepper motor driver circuit according to claim 7 , wherein the current control circuit
controls the driving current to increase an average value of an absolute value of the driving current in a case where the comparison result signal indicates that the measurement value is equal to or greater than the threshold.

18 . The stepper motor driver circuit according to claim 6 , further comprising a logic circuit that outputs a control signal based on the reference clock signal and the command signal input from the outside,
wherein the current control circuit controls the driving current in response to the control signal.

19 . The stepper motor driver circuit according to claim 7 , further comprising a logic circuit that outputs a control signal based on the reference clock signal and the command signal input from the outside,
wherein the current control circuit controls the driving current in response to the control signal.

20 . The stepper motor driver circuit according to claim 12 , wherein the current control circuit
controls the driving current to make the pseudo-sinusoidal waveform of the driving current closer to a sinusoidal waveform in a case where the comparison result signal indicates that the measurement value is smaller than the threshold.

Assignees

• Toshiba Kk

Inventors

• Kimura Hideki
• Sasaki Katsunori

Classifications

• H02P8/18

  Shaping of pulses, e.g. to reduce torque ripple {(Reducing overshoot H02P8/32 takes precedence)} · CPC title

• H02P29/50 Primary

  Reduction of harmonics · CPC title

• H02P8/34

  Monitoring operation (H02P8/36 takes precedence) · CPC title

• H02P8/12 Primary

  Control or stabilisation of current · CPC title