Keith W Wolford

US Patent:

60086033, Dec 28, 1999

Filed:

Oct 28, 1998

Appl. No.:

9/181930

Inventors:

Steven C. Jones - Allen TX
Keith Wolford - Allen TX

Assignee:

Texas Instruments Incorporated - Dallas TX

International Classification:

H02K 2300

US Classification:

318254

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.

US Patent:

59527986, Sep 14, 1999

Filed:

Oct 28, 1998

Appl. No.:

9/181252

Inventors:

Steven C. Jones - Allen TX
Keith Wolford - Allen TX

Assignee:

Texas Instruments Incorporated - Dallas TX

International Classification:

H02P 100

US Classification:

318268

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.