Brushless motor driving circuit and portable terminal incorporating the same

• US 6,822,406 B2
• Filed: 08/01/2002
• Issued: 11/23/2004
• Est. Priority Date: 08/14/2001
• Status: Expired due to Fees

• Current Assignee: Sony Corporation (Sony Group Corp.)
• Original Assignee: Sony Corporation (Sony Group Corp.)
• Inventors: Kikuchi, Masafumi, Suzuki, Masahiro, Suzuki, Hitoshi, Fujino, Akira
• Primary Examiner(s): Tamai, Karl
• Assistant Examiner(s): Comas, Yahveh
• Application Number:
  US10/209,622
• Publication Number:
  US 20030034704A1
• Time in Patent Office: 845 Days
• Field of Search: 310/80, 310/81, 318/254, 318/778, 318/114
• US Class Current: 318/114
• CPC Class Codes: H02P 6/085 in a bridge configuration
• CPC Class Codes: H02P 6/182 using back-emf in windings

Abstract

A brushless motor-driving circuit is disclosed which includes an initializing element setting an initial rotating speed, an oscillating element for generating a frequency corresponding to the initial rotating speed set by the initializing element, a frequency-controlling element for causing the frequency generated by the oscillating element to change from the frequency corresponding to the initial rotating speed to a frequency corresponding to a constant rotating speed, a driving-signal-generating element for generating driving signals having a plurality of phases based on the generated frequency of the oscillating element, and a driving element for driving coils having a plurality of phases based on the driving signals having the plurality of phases generated by the driving-signal-generating element.

Claims

1. A brushless motor-driving circuit comprising:

initializing means setting an initial rotating speed;

oscillating means for generating a frequency corresponding to said initial rotating speed set by said initializing means;

frequency-controlling means for causing the frequency generated by said oscillating means to change from the frequency corresponding to said initial rotating speed to a frequency corresponding to a constant rotating speed;

driving-signal-generating means for generating driving signals having a plurality of phases based on the generated frequency of said oscillating means;

driving means for driving coils having a plurality of phases based on said driving signals having said plurality of phases generated by said driving-signal-generating means; and

braking means for selectively blocking the supply of said generated frequency of said oscillating means to said driving-signal-generating means.

2. A brushless motor-driving circuit according to claim 1, wherein said frequency-controlling means includes a time-constant circuit for providing a time-constant, said frequency-controlling means causing said generated frequency of said oscillating means to change in accordance with said time-constant.

3. A brushless motor-driving circuit according to claim 1, further comprising detecting means for detecting a rotating state of a brushless motor based on a counter-electromotive voltage generated by one of said coils having said plurality of phases.

4. A brushless motor-driving circuit according to claim 3, wherein, on detecting a stopped state of said brushless motor, said detecting means resets the processing of said frequency-controlling means.

5. A brushless motor-driving circuit according to claim 1, wherein said driving means changes an on/off duty of driving transistors depending on a supply voltage for driving a brushless motor.

6. A portable terminal incorporating a vibrating motor for vibrating an enclosure and a motor-driving circuit for driving said vibrating motor upon receipt of an incoming call, wherein said motor-driving circuit comprises:

initializing means setting an initial rotating speed;

oscillating means for generating a frequency corresponding to said initial rotating speed set by said initializing means;

frequency-controlling means for causing the frequency generated by said oscillating means to change from the frequency corresponding to said initial rotating speed to a frequency corresponding to a constant rotating speed;

driving-signal-generating means for generating driving signals having a plurality of phases based on the generated frequency of said oscillating means;

driving means for driving coils having a plurality of phases based on said driving signals having said plurality of phases generated by said driving-signal-generating means; and

braking means for selectively blocking the supply of said generated frequency of said oscillating means to said driving-signal-generating means.

7. A portable terminal according to claim 6, wherein said frequency-controlling means comprises a time-constant circuit for providing a time-constant, and said frequency-controlling means causes said generated frequency of said oscillating means to change in accordance with said time-constant.

8. A portable terminal according to claim 6, further comprising detecting means for detecting a rotating state of said vibrating motor based on a counter-electromotive voltage generated by one of said coils having said plurality of phases, wherein, on detecting a stopped state of said vibrating motor, said detecting means resets the processing of said frequency-controlling means.

9. A portable terminal according to claim 6, wherein said driving means changes an on/off duty of driving transistors depending on a supply voltage for driving said vibrating motor.