Patent US4459527A successfully refreshed from Google Patents.
US4459527A
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US
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Stepper motor control circuit
Assignee: Cubic Western Data Corp
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Filing: 1983-03-23
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Granted: 1984-07-10
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Expires: 2003-03-23
Abstract
Abstract A digital input signal is fed through an interface to a logic phase control which decodes the signal to provide a plurality of phase signals in a predetermined relationship for driving a sychronous DC stepper motor. The phase signals are fed to corresponding phase drivers which amplify the pulses of the phase signals before they are applied to the corresponding phase windings of the stepper motor. Each phase driver includes an operational amplifier and a power transistor connected in a closed loop to provide a current pulse having a constant predetermined peak amplitude to the corresponding phase winding during acceleration of the motor. The inductive time constant of the motor phase windings is thus overcome so that an applied mechanical load can be rapidly accelerated without stalling and the absence of dropping resistors minimizes power dissipation and heat generation. A pulse detector turns off the phase drivers after a predetermined time interval following the last pulse of the digital input signal to provide a time brake holding torque and near zero standby power comsumption. Components in the circuit are provided for protecting the power transistors from breakdown due to back emf signals generated in the phase windings.
Inventors
- 👤 Charles L. Hayman
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-30 11:16
CPC Classifications
H; H02; H02P; H02P8/00; H02P8/12
Claims Analysis
Total Claims: 16
Claim 1
Independent Claim
146 words
A circuit for controlling a stepper motor having a predetermined number of phase windings in response to a digital input signal comprising: means for decoding the digital input signal to provide a plurality of phase signals in a predetermined relationship for driving the stepper motor when amplified and applied to corresponding ones of the phase windings; and a plurality of driver means, each for amplifying one of the phase signals and applying it to its corresponding one of the phase windings, each driver means including an operational amplifier, a power transistor connected in a closed loop to provide a current pulse having a predetermined peak amplitude to the corresponding one of the phase windings during acceleration of the stepper motor, and means for clamping the voltage of back emf signals so that it does not rise above the predetermined voltage breakdown level of the power transistors.
Claim 2
Dependent Claim
146 words
A circuit for controlling a stepper motor having a predetermined number of phase windings in response to a digital input signal comprising: means for decoding the digital input signal to provide a plurality of phase signals in a predetermined relationship for driving the stepper motor when amplified and applied to corresponding ones of the phase windings; and a plurality of driver means, each for amplifying one of the phase signals and applying it to its corresponding one of the phase windings, each driver means including an operational amplifier, a power transistor connected in a closed loop to provide a current pulse having a predetermined peak amplitude to the corresponding one of the phase windings during acceleration of the stepper motor, and means for clamping the voltage of back emf signals so that it does not rise above the predetermined voltage breakdown level of the power transistors.
Claim 3
Dependent Claim
35 words
A circuit according to claim 1 and further comprising timer means for turning off all of the driver means if no digital input signal is received by the decoding means during a predetermined time interval.
Claim 4
Dependent Claim
35 words
A circuit according to claim 1 wherein each of the driver means includes means for protecting its power transistor from secondary breakdown due to back emf signal in the corresponding one of the phase windings.
Claim 5
Dependent Claim
35 words
A circuit according to claim 1 and further comprising means for protecting the power transistors in all of the driver means from voltage breakdown due to back emf signals in each of the phase windings.
Claim 6
Dependent Claim
34 words
A circuit according to claim 1 wherein the decoding means includes CMOS logic circuitry operated with a split power supply for enabling the operational amplifiers to be completely turned off by the decoding means.
Claim 7
Dependent Claim
16 words
A circuit according to claim 2 wherein the timer means includes a one shot monostable multivibrator.
Claim 8
Dependent Claim
31 words
A circuit according to claim 3 wherein the protecting means includes a transistor connected for rapidly evacuating the base charge from the power transistor when the operational amplifier is turned off.
Claim 9
Dependent Claim
26 words
A circuit according to claim 1 wherein the protecting means includes a transzorb connected between the return terminal of a power supply and the power transistors.
Claim 10
Dependent Claim
33 words
A circuit according to claim 1 wherein each of the phase drivers has a diode connected across the collector and emitter of its power transistor to protect the transistor from reverse voltage breakdown.
Claim 11
Dependent Claim
148 words
A circuit for controlling a stepper motor having a predetermined number of phase windings in response to a digital input signal comprising: means for decoding the digital input signal to provide a plurality of phase signals in a predetermined relationship for driving the stepper motor when amplified and applied to corresponding one of the phase windings, the decoding means including CMOS logic circuitry operated with a split power supply for enabling the operational amplifiers to be completely turned off by the decoding means; and a plurality of driver means, each for amplifying one of the phase signals and applying it to its corresponding one of the phase windings, each driver means including an operational amplifier and a power transistor connected in a closed loop to provide a current pulse having a predetermined peak amplitude to the corresponding one of the phase windings during acceleration of the stepper motor.
Claim 12
Dependent Claim
148 words
A circuit for controlling a stepper motor having a predetermined number of phase windings in response to a digital input signal comprising: means for decoding the digital input signal to provide a plurality of phase signals in a predetermined relationship for driving the stepper motor when amplified and applied to corresponding one of the phase windings, the decoding means including CMOS logic circuitry operated with a split power supply for enabling the operational amplifiers to be completely turned off by the decoding means; and a plurality of driver means, each for amplifying one of the phase signals and applying it to its corresponding one of the phase windings, each driver means including an operational amplifier and a power transistor connected in a closed loop to provide a current pulse having a predetermined peak amplitude to the corresponding one of the phase windings during acceleration of the stepper motor.
Claim 13
Dependent Claim
172 words
A circuit for controlling a stepper motor having a predetermined number of phase windings in response to a digital input signal comprising: means for decoding the digital input signal to provide a plurality of phase signals in a predetermined relationship for driving the stepper motor when amplified and applied to corresponding ones of the phase windings; and a plurality of driver means, each for amplifying one of the phase signals and applying it to its corresponding one of the phase windings, each driver means including an operational amplifier and a power transistor connected in a closed loop to provide a current pulse having a predetermined peak amplitude to the corresponding one of the phase windings during acceleration of the stepper motor, each driver means further including means for protecting its power transistor from secondary breakdown due to back emf signals in the corresponding one of the phase windings, said protecting means including a transistor connected for rapidly evacuating the base charge from the power transistor when the operational amplifier is turned off.
Claim 14
Dependent Claim
172 words
A circuit for controlling a stepper motor having a predetermined number of phase windings in response to a digital input signal comprising: means for decoding the digital input signal to provide a plurality of phase signals in a predetermined relationship for driving the stepper motor when amplified and applied to corresponding ones of the phase windings; and a plurality of driver means, each for amplifying one of the phase signals and applying it to its corresponding one of the phase windings, each driver means including an operational amplifier and a power transistor connected in a closed loop to provide a current pulse having a predetermined peak amplitude to the corresponding one of the phase windings during acceleration of the stepper motor, each driver means further including means for protecting its power transistor from secondary breakdown due to back emf signals in the corresponding one of the phase windings, said protecting means including a transistor connected for rapidly evacuating the base charge from the power transistor when the operational amplifier is turned off.
Claim 15
Dependent Claim
142 words
A circuit for controlling a stepper motor having a predetermined number of phase windings in response to a digital input signal comprising: means for decoding the digital input signal to provide a plurality of phase signals in a predetermined relationship for driving the stepper motor when amplified and applied to corresponding ones of the phase windings; and a plurality of driver means, each for amplifying one of the phase signals and applying it to its corresponding one of the phase windings, each driver means including an operational amplifier and a power transistor connected in a closed loop to provide a current pulse having a predetermined peak amplitude to the corresponding one of the phase windings during acceleration of the stepper motor, including a diode connected across the collector and emitter of the power transistor to protect the transistor from reverse voltage breakdown.
Claim 16
Dependent Claim
142 words
A circuit for controlling a stepper motor having a predetermined number of phase windings in response to a digital input signal comprising: means for decoding the digital input signal to provide a plurality of phase signals in a predetermined relationship for driving the stepper motor when amplified and applied to corresponding ones of the phase windings; and a plurality of driver means, each for amplifying one of the phase signals and applying it to its corresponding one of the phase windings, each driver means including an operational amplifier and a power transistor connected in a closed loop to provide a current pulse having a predetermined peak amplitude to the corresponding one of the phase windings during acceleration of the stepper motor, including a diode connected across the collector and emitter of the power transistor to protect the transistor from reverse voltage breakdown.
References Cited (Backward Citations)
US4107593A
Cited
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1987-07-10 | 1988-01-09 | 1988-07-10 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1991-07-10 | 1992-01-09 | 1992-07-10 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1995-07-10 | 1996-01-09 | 1996-07-10 | $7700.00 | Window Closed / Lapsed |