Brushless DC motor assembly control circuit
First Claim
1. A two-phase brushless motor assembly, receiving a first wire providing electric power, a second wire providing a ground connection, and a third wire, comprising:
- a two-phase brushless motor, including a rotor, and including a first winding and a second winding on a stator;
a sensor circuit providing a sensed speed signal representing at least the rotational position of said rotor; and
a motor drive circuit, responsive to a speed control voltage signal on said third wire and said electric power on said first wire, providing drive power to said motor to drive said motor to a speed determined by said speed control voltage signal, said motor drive circuit comprisinga pulse width modulator responsive to said speed control voltage signal for providing a pulsed motor drive control signal in pulses having a width modulated in accordance with the value of the voltage of said speed control voltage signal,a power drive circuit coupled to said first wire and responsive to said pulse width modulator for providing pulsed electric power to a common connection terminal for a first end of said first winding and for a first end of said second winding of said motor in pulses determined by said pulsed motor drive control signal,an output drive logic control circuit responsive to said sensor circuit and coupled to a second end of said first winding and to a second end of said second winding, providing a return path for said pulsed electric power through said first winding and through said second winding, alternatingly, anda circulating circuit path through ground, for conducting a circulating current through said first winding and through said second winding, during intervals between said pulses of said pulsed electric power, alternating between said first winding and said second winding.
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Accused Products
Abstract
A novel two-phase brushless motor drive assembly. The motor drive assembly is made of two parts, a motor assemble and a motor control circuit.
The motor assembly, receives a first wire providing electric power, a second wire providing a ground connection, and a third wire. The motor assembly includes, a two-phase brushless motor. It also includes a motor drive circuit, responsive to a speed control voltage signal on the third wire and the electric power on the first wire, providing drive power to the motor to drive the motor to a speed determined by the speed control voltage signal. The motor assembly also includes a sensor circuit providing a sensed speed current signal on the third wire, having a current representing the rotational speed of the motor.
The motor control circuit is coupled to the third wire, and includes a speed control circuit responsive to a speed control signal for generating the speed control voltage signal on the third wire at a voltage corresponding to a speed indicated by the speed control signal. It also includes a current sensing circuit providing a speed signal, corresponding to the sensed speed current signal on the third wire, such that the voltage of the speed control voltage signal is substantially unaffected by changes in the current of the sensed speed current signal, and such that the current of the sensed speed current signal is substantially unaffected by changes in the voltage of the speed control voltage signal.
80 Citations
3 Claims
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1. A two-phase brushless motor assembly, receiving a first wire providing electric power, a second wire providing a ground connection, and a third wire, comprising:
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a two-phase brushless motor, including a rotor, and including a first winding and a second winding on a stator; a sensor circuit providing a sensed speed signal representing at least the rotational position of said rotor; and a motor drive circuit, responsive to a speed control voltage signal on said third wire and said electric power on said first wire, providing drive power to said motor to drive said motor to a speed determined by said speed control voltage signal, said motor drive circuit comprising a pulse width modulator responsive to said speed control voltage signal for providing a pulsed motor drive control signal in pulses having a width modulated in accordance with the value of the voltage of said speed control voltage signal, a power drive circuit coupled to said first wire and responsive to said pulse width modulator for providing pulsed electric power to a common connection terminal for a first end of said first winding and for a first end of said second winding of said motor in pulses determined by said pulsed motor drive control signal, an output drive logic control circuit responsive to said sensor circuit and coupled to a second end of said first winding and to a second end of said second winding, providing a return path for said pulsed electric power through said first winding and through said second winding, alternatingly, and a circulating circuit path through ground, for conducting a circulating current through said first winding and through said second winding, during intervals between said pulses of said pulsed electric power, alternating between said first winding and said second winding. - View Dependent Claims (2, 3)
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Specification
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- Resources
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Current AssigneeTexas Instruments, Inc.
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Original AssigneeTexas Instruments, Inc.
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InventorsWolford, Keith, Jones, Steven C.
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Primary Examiner(s)Masih, Karen
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Application NumberUS09/181,252Time in Patent Office321 DaysField of Search318/268, 318/747, 318/254, 318/138, 318/439, 318/779US Class Current318/268CPC Class CodesH02P 6/08 Arrangements for controllin...
