US3988652A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Stabilized brushless motor drive circuit
Assignee: Suwa Seikosha KK
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Filing: 1975-04-09
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Granted: 1976-10-26
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Expires: 1995-04-09
Abstract
Abstract A brushless motor drive circuit including at least one hall effect element and a drive transistor circuit adapted to produce a signal to energize at least two drive coils, which coils operate to drive the brushless motor. The amplitude of the signal applied to said drive coils is determined by the current supplied to the drive transistor circuit. A control circuit is provided for controlling said supplied current in response to the speed of the motor. The control circuit includes a single transistor coupled to said drive transistor circuit, the series connection of a constant voltage produced by a voltage limiting device and a voltage representative of motor speed being coupled to the base of the transistor to bias the control transistor to maintain a constant motor speed.
Inventors
- 👤 Takeshi Endo
- 👤 Yoshihiro Mitsui
- 👤 Hiroshi Kamakura
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-29 08:07
CPC Classifications
H; H02; H02P; H02P6/00; H02P6/14; H02P6/16
Claims Analysis
Total Claims: 11
Claim 1
Independent Claim
180 words
In a brushless motor circuit having at least one hall effect element for controlling the duration of application of driving current to a driving coil, the improvement comprising drive transistor means adapted to receive signals from said hall effect element and in response thereto control the amplitude of the current applied to the drive coil for the duration determined by said hall effect element, control transistor means connected by the emitter-collector path thereof to said drive transistor means to control the amplitude of the current supplied to said driving coil thereby; means for detecting a voltage proportional to the rotational speed of said brushless motor; means for producing a fixed reference voltage; means connecting said fixed reference voltage and said voltage proportional to the rotational speed of said rotor in series to the base of said control transistor means for linearly controlling the amplitude of the current supplied to said driving coil by said drive transistor means in response to variations in the voltage proportional to the rotational speed of said motor to maintain said speed at a predetermined level.
Claim 2
Dependent Claim
180 words
In a brushless motor circuit having at least one hall effect element for controlling the duration of application of driving current to a driving coil, the improvement comprising drive transistor means adapted to receive signals from said hall effect element and in response thereto control the amplitude of the current applied to the drive coil for the duration determined by said hall effect element, control transistor means connected by the emitter-collector path thereof to said drive transistor means to control the amplitude of the current supplied to said driving coil thereby; means for detecting a voltage proportional to the rotational speed of said brushless motor; means for producing a fixed reference voltage; means connecting said fixed reference voltage and said voltage proportional to the rotational speed of said rotor in series to the base of said control transistor means for linearly controlling the amplitude of the current supplied to said driving coil by said drive transistor means in response to variations in the voltage proportional to the rotational speed of said motor to maintain said speed at a predetermined level.
Claim 3
Dependent Claim
87 words
A brushless motor drive circuit as claimed in claim 1, wherein said drive transistor means includes a first drive transistor coupled to said drive coil, and a further drive transistor intermediate said hall effect element and first drive transistor, the collector emitter path of said further transistor being coupled to said emitter-collector path of said control transistor means, said further transistor controlling the amplitude of the driving current applied to said drive coil by said first drive transistor for a duration determined by said hall effect element.
Claim 4
Dependent Claim
23 words
A brushless motor drive circuit as claimed in claim 1, wherein said means for producing said fixed reference voltage includes Zener diode means.
Claim 5
Dependent Claim
71 words
A brushless motor drive circuit as claimed in claim 3, wherein said means for producing said fixed reference voltage includes voltage divider means including a fixed resistor and a variable resistor connected in series, said voltage divider means being connected in parallel with Zener diode means, said fixed resistor being connected in series with the base of said control transistor means and said voltage proportional to the speed of said motor.
Claim 6
Dependent Claim
21 words
A brushless motor drive circuit as claimed in claim 4, including temperature compensating means connected in parallel with said fixed resistor.
Claim 7
Dependent Claim
36 words
A brushless motor drive circuit as claimed in claim 5, wherein said means for detecting a voltage proportional to said rotor speed includes capacitor means for storing said voltage connected in series with said fixed resistor.
Claim 8
Dependent Claim
40 words
A brushless motor drive circuit as claimed in claim 6, wherein said means for detecting a voltage proportional to the speed of said motor includes diode means connecting said capacitor and said driving coil for detecting the voltage induced therein.
Claim 9
Dependent Claim
40 words
A brushless motor drive circuit as defined in claim 6, wherein said means for detecting a voltage proportional to the speed of said motor includes a detecting coil means and diode means connecting said detecting coil means and said capacitor.
Claim 10
Dependent Claim
19 words
A brushless motor drive circuit as claimed in claim 1, wherein said control transistor means comprises a single transistor.
Claim 11
Dependent Claim
19 words
A brushless motor drive circuit as claimed in claim 2, wherein said control transistor means comprises a single transistor.
References Cited (Backward Citations)
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1979-10-26 | 1980-04-26 | 1980-10-26 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1983-10-26 | 1984-04-26 | 1984-10-26 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1987-10-26 | 1988-04-26 | 1988-10-26 | $7700.00 | Window Closed / Lapsed |