Servo-control apparatus for motor

• US 6,713,983 B2
• Filed: 03/27/2002
• Issued: 03/30/2004
• Est. Priority Date: 04/27/1999
• Status: Expired due to Fees

• Current Assignee: Canon Kabushiki Kaisha (Canon Inc.)
• Original Assignee: Canon Kabushiki Kaisha (Canon Inc.)
• Inventors: Maruyama, Shoji
• Primary Examiner(s): Masih, Karen
• Application Number:
  US10/106,318
• Publication Number:
  US 20020101213A1
• Time in Patent Office: 734 Days
• Field of Search: 318/560, 318/568.1, 318/568.2, 318/567, 318/565, 318/555, 318/254, 318/811, 318/138, 318/43.9, 318/700, 318/705, 318/806, 318/609
• US Class Current: 318/560
• CPC Class Codes: H02P 6/04 Arrangements for controlling or regulating the speed or torque of more than one motor H02P6/10 takes precedence
• CPC Class Codes: H02P 6/085 in a bridge configuration

Abstract

The present invention provides a servo-control apparatus for a motor, comprising position detecting means for detecting a rotational position of a motor, rotational speed signal generating means for generating a rotational speed signal corresponding to a rotational speed of a motor, and digital control means for generating an exciting electric current to be supplied to a coil of the motor as a PWM signal in accordance with the rotational speed signal from the rotational speed signal generating means, and wherein a switching signal for switching the exciting electric current to be supplied to the coil of the motor is formed by a pre-driver in accordance with the position detection signal from the position detecting means, and the pre-driver combines the switching signal with the PWM signal from the digital control means to generate an electric current control signal by which the motor is driven, thereby coping with the speed change of the motor quickly and stably.

Claims

1. A pre-driver circuit connectable with both a motor driver for driving a motor and a digital processor for servo-controlling a plurality of motors by performing a programmed calculation and inputting/outputting signals through an interface pin, said pre-driver circuit comprising:

a speed detection signal receiver adapted for receiving a speed detection signal representing a rotational speed of said motor, from a rotational speed detector;

an amplifying unit adapted for amplifying said speed detection signal received by said speed detection signal receiver;

a sender connectable with one of pins of said digital processor, adapted for sending the speed detection signal amplified by said amplifying unit, to the digital processor;

a first receiver connectable with one of a plurality of pins of said digital processor, adapted for receiving a start signal for starting to drive said motor;

a second receiver connectable with one of a plurality of pins of said digital processor, adapted for receiving a pulse width modulated signal generated by the digital processor based on said speed detection signal sent by said sender for servo-controlling the rotational speed of said motor;

a position detection signal receiver adapted for receiving a position detection signal representing a rotational position of said motor, from a position detector; and

a control signal generator adapted for generating a control signal to control driving signals supplied to each phase of said motor, in accordance with said pulse width modulated signal received by said second receiver and said position detection signal received by said position detection signal receiver when the start signal received by said first receiver is active, and supplying the generated signal to said motor driver.

2. A pre-driver circuit according to claim 1, wherein

said control signal generator comprises:

a switching signal generating unit adapted for generating a switching signal for switching the driver signals supplied to each coil of said motor, in accordance with said position detection signal received by the position detection signal receiver; and

a combining unit adapted for combining the pulse width modulated signal received by said first receiver, with said switching signal generated by said switching signal generating unit.

3. A pre-driver circuit according to claim 1, wherein said control signal generator generates six signals as said control signal to control driving signals supplied to each coil of a three phase motor having three coils.

4. A pre-driver circuit according to claim 1, wherein said second receiver receives three phase signals as said position detection signal representing a rotational position of a three phase motor having three coils.

5. A pre-driver circuit according to claim 1, further comprising:

an electrical power receiver adapted for inputting electrical power;

a charge pump unit for charge-pumping an electrical voltage input by said electrical power receiver; and

an electrical power supplying unit for supplying the electrical power charge pumped by said charge pump unit with a driver for driving said motor.

6. A pre-driver circuit connectable with both a motor driver for driving a motor and a digital processor for servo-controlling a plurality of motors by performing a programmed calculation and inputting/outputting signals through a plurality of interface pins, said pre-driver circuit comprising:

a first receiver connectable with one of a plurality of pins of said digital processor, adapted for receiving a start signal for starting to drive said motor;

a second receiver connectable with one of a plurality of pins of said digital processor, adapted for receiving a pulse width modulated signal generated by the digital processor based on a speed detection signal for servo-controlling the rotational speed of said motor;

a position detection signal receiver adapted for receiving a position detection signal representing a rotational position of said motor, from a position detector; and

a control signal generator adapted for generating a control signal to control driving signals supplied to each phase of said motor, in accordance with said pulse width modulated signal received by said second receiver and said position detection signal received by said position detection signal receiver when the start signal received by said first receiver is active, and supplying the generated signal to said motor driver.

7. A pre-driver circuit according to claim 6, wherein said control signal generator comprises:

a switching signal generating unit adapted for generating a switching signal for switching the driving signals supplied to each coil of said motor, in accordance with said position detection signal received by said position detection signal receiver; and

a combining unit adapted for combining the pulse width modulated signal received by said first receiver, with said switching signal generated by said switching signal generating unit.

8. A pre-driver circuit according to claim 6, wherein said control signal generates six signals as said control signal to control driving signals supplied to each coil of a three-phase motor having three coils.

9. A pre-driver circuit according to claim 6, wherein said second receiver receives three phase signals as said position detection signal representing a rotational position of a three-phase motor having three coils.

10. A pre-driver circuit according to claim 6, wherein said pre-driver circuit further comprises:

an electrical power receiver adapted for inputting electrical power;

a charge pump unit for charge-pumping an electrical voltage input by said electrical power receiver; and

an electrical power supplying unit for supplying the electrical power charge-pumped by said charge pump unit with a driver for driving said motor.

11. A pre-driver circuit connectable with both a motor driver for driving a motor and a digital processor for servo-controlling a plurality of motors by performing a programmed calculation and inputting/outputting signals through a plurality of interface pins, said pre-driver circuit comprising:

a speed detection signal receiver adapted for receiving a speed detection signal representing a rotational speed of said motor, from a rotational speed detector;

an amplifying unit adapted for amplifying said speech detection signal received by said speed detection signal receiver;

sender connectable with one of a plurality of pins of said digital processor, adapted for sending the speed detection signal amplified by said amplifying unit, to the digital processor;

a receiver connectable with one of a plurality of pins of said digital processor, adapted for receiving a pulse width modulated signal generated by the digital processor based on said speed detection signal sent by said sender for servo-controlling the rotational speed of said motor;

a position detection signal receiver adapted for receiving a position detection signal representing a rotational position of said motor, from a position detector; and

a control signal generator adapted for generating a control signal to control driving signals supplied to each phase of said motor, in accordance with said pulse width modulated signal received by said receiver and said position detection signal received by said position detection signal receiver, and supplying the generated signal to said motor driver.

12. A pre-driver circuit according to claim 11, wherein said control signal generator comprises:

a switching signal generating unit adapted for generating switching signal for switching the driving signals supplied to each coil of said motor, in accordance with said position detection signal received by said position detection signal receiver; and

a combining unit adapted for combining the pulse width modulated signal received by said first receiver, with said switching signal generated by said switching signal generating unit.

13. A pre-driver circuit according to claim 11, wherein said control signal generates six signals as said control signal to control driving signals supplied to each coil of a three-phase motor having three coils.

14. A pre-driver circuit according to claim 11, wherein said second receiver receives three phase signals as said position detection signal representing a rotational position of a three-phase motor having three coils.

15. A pre-driver circuit according to claim 11, wherein said pre-driver circuit further comprises:

an electrical power receiver adapted for inputting an electrical power;

a charge pump unit for charge-pumping an electrical voltage input by said electrical power receiver; and

an electrical power supplying unit for supplying the electrical power charge-pumped by said charge pump unit a driver for driving said motor.