Phase detector, motor drive controller, motor apparatus, sheet feeder, and method of detecting phase

Patent metadata

Field	Value
Publication number	US-9682835-B2
Application number	US-201514936904-A
Country	US
Kind code	B2
Filing date	Nov 10, 2015
Priority date	Nov 21, 2014
Publication date	Jun 20, 2017
Grant date	Jun 20, 2017

Abstract

A phase detector is provided. The phase detector includes a signal selector, a bias level generator, and a phase information detector. The signal selector selects, as a selected sensor signal, one of a plurality of sensor signals each having a signal level corresponding to a phase of a rotor. The bias level generator divides a signal level difference between a pair of sensor signals, including the selected sensor signal and other sensor signal of the plurality of sensor signals other than the selected sensor signal, at a first ratio, to generate a first bias level. The phase information detector generates a threshold level corresponding to the phase of the rotor based on the first bias level, and detects the signal level of the selected sensor signal reaching the threshold level.

First claim

What is claimed is:

1. A phase detector, comprising:
a signal selector to select, as a selected sensor signal, one of a plurality of sensor signals each having a signal level corresponding to a phase of a rotor;
a bias level generator to divide a signal level difference between a pair of sensor signals at a first ratio, the pair of sensor signals including the selected sensor signal and other sensor signal of the plurality of sensor signals other than the selected sensor signal, to generate a first bias level; and
a phase information detector to generate a threshold level corresponding to the phase of the rotor based on the first bias level, and to detect the signal level of the selected sensor signal reaching the threshold level.

2. The phase detector according to claim 1 , wherein the phase information detector generates the threshold level corresponding to the phase of the rotor based on the first bias level, so that the first bias level coincides with the signal level of the selected sensor signal at a phase of an intersection of the pair of sensor signals.

3. The phase detector according to claim 1 , wherein the phase information detector divides a signal level section at a second ratio corresponding to the phase of the rotor, the signal level section having an upper end or a lower end corresponding to the first bias level, to generate the threshold level.

4. The phase detector according to claim 1 ,
wherein the bias level generator divides a first signal level difference between the selected sensor signal and a first sensor signal having a signal level greater than that of the selected sensor signal at the first ratio to generate the first bias level, and
wherein the bias level generator divides a second signal level difference between the selected sensor signal and a second sensor signal having a signal level smaller than that of the selected sensor signal at the first ratio to generate a second bias level.

5. The phase detector according to claim 4 , wherein the phase information detector divides a signal level section at a second ratio corresponding to the phase of the rotor, the signal level section having an upper end and a lower end respectively corresponding to the first bias level and the second bias level, to generate the threshold level.

6. The phase detector according to claim 1 ,
wherein the signal selector selects, as the selected sensor signal, one of the plurality of sensor signals for each of a plurality of phase sections, and connects the selected sensor signals at boundaries between the phase sections adjacent to each other, and
wherein the bias level generator generates the first bias level for each of the plurality of phase sections, and connects the generated first bias levels at the boundaries between the phase sections adjacent to each other.

7. The phase detector according to claim 1 , wherein the first ratio has a value that divides the signal level difference between the pair of sensor signals into two halves.

8. The phase detector according to claim 1 , wherein the first ratio has a value that divides the signal level difference between the pair of sensor signals so that the first bias level comes closer to a signal level of the other sensor signal than the signal level of the selected sensor signal.

9. The phase detector according to claim 1 , further comprising:
an intersection phase detector to compare two of the plurality of sensor signals to detect a phase of an intersection of the two sensor signals,
wherein the signal selector selects one of the plurality of sensor signals upon detection of the phase of the intersection by the intersection phase detector.

10. The phase detector according to claim 1 , wherein each of the sensor signals has a waveform of sine wave or a wave similar to sine wave.

11. The phase detector according to claim 1 , wherein the signal level of each of the sensor signals corresponds to a rotation phase of the rotor including a coil having a plurality of phases.

12. A motor drive controller, comprising:
the phase detector according to claim 1 to output a phase detection result;
a motor controller to output a signal based on the phase detection result; and
a motor driver to drive a motor based on the signal.

13. A motor apparatus, comprising:
the motor drive controller according to claim 12 ; and
a motor to be driven by the motor drive controller.

14. A sheet feeder, comprising:
the motor apparatus according to claim 13 ;
a plurality of rollers at least one of which is to be driven by the motor apparatus; and
a belt stretched across the plurality of rollers to be fed by the plurality of rollers.

15. A method of detecting phase, comprising:
selecting, as a selected sensor signal, one of a plurality of sensor signals each having a signal level corresponding to a phase of a rotor;
dividing a signal level difference between a pair of sensor signals at a first ratio, the pair of sensor signals including the selected sensor signal and other sensor signal of the plurality of sensor signals other than the selected sensor signal (X), to generate a first bias level;
generating a threshold level corresponding to the phase of the rotor based on the first bias level; and
detecting the signal level of the selected sensor signal reaching the threshold level.

Assignees

• Kamatani Tomohiko
• Ricoh Co Ltd

Inventors

• Kamatani Tomohiko

Classifications

• B65H2403/00

  Power transmission; Driving means · CPC title

• B65H5/021 Primary

  by belts · CPC title

• H02P6/16 Primary

  Circuit arrangements for detecting position · CPC title

• G01D5/243

  influencing the phase or frequency of AC · CPC title

• B65H2211/00

  Operations & Transport · mapped topic