Motor control circuit and associated full bridge switching arrangement

• US 7,309,968 B2
• Filed: 10/03/2002
• Issued: 12/18/2007
• Est. Priority Date: 10/05/2001
• Status: Expired due to Fees

• Current Assignee: Minebea Company Limited (MinebeaMitsumi Inc.)
• Original Assignee: Minebea Company Limited (MinebeaMitsumi Inc.)
• Inventors: Riddoch, Henry, Strike, Nigel D.
• Primary Examiner(s): Patel, Rajnikant B.
• Application Number:
  US10/490,967
• Publication Number:
  US 20040264226A1
• Time in Patent Office: 1,902 Days
• Field of Search: 318/254, 318/138, 318/439, 318/701, 318/685, 318/696, 318/370, 318/757, 318/762, 318/758, 363/132, 363/131, 363/34, 363/37, 363/39, 363 56- 58
• US Class Current: 318/254.1
• CPC Class Codes: H02M 1/08 Circuits specially adapted for the generation of control voltages for semiconductor devices incorporated in static converters
• CPC Class Codes: H02P 6/00 Arrangements for controlling synchronous motors or other dynamo-electric motors using electronic commutation dependent on the rotor position; Electronic commutators therefor vector control H02P21/00
• CPC Class Codes: H02P 6/32 Arrangements for controlling wound field motors, e.g. motors with exciter coils
• CPC Class Codes: H03K 17/063 in field-effect transistor switches

Abstract

A motor control circuit for controlling a motor, the circuit comprising a switched mode power supply operable to drive a full bridge switching transistor arrangement and to provide a stable voltage to the motor control circuit, wherein the switching transistor arrangement is connectable to the windings of the motor to be controlled, and wherein the switching transistor arrangement comprises: a first set of transistors in an upper part of the full bridge and a second set of transistors in a lower part of the full bridge, the first set of transistors being driven by a first output of the switched mode power supply and the second set of transistors being driven by a second output of the switched mode power supply.

Claims

1. A motor control circuit for controlling a brushless DC motor, the circuit comprising a lower DC power supply rail and an upper DC power supply rail having a predetermined voltage relative to said lower DC power supply rail,

a full bridge switching transistors arrangement connected between the upper and lower DC power supply rails, said switching transistors being n-type FETs,

and wherein the switching transistors arrangement comprises:

a first set of n-type FETs in an upper part of the full bridge and a second set of n-type FETs in a lower part of the full bridge,

the motor control circuit further comprising a DC motor controller and a switched mode power supply which comprises;

a transformer with a primary winding connected in series with a switching transistor, between said upper and lower DC power supply rails and a first secondary winding driving a first output and tied to the upper DC power supply rail such that the effective voltage at said first output is the sum of the voltage due to said first secondary winding and the predetermined voltage,

the first set of FETs being driven by driver circuitry supplied by said first output of the switched mode power supply and controlled by the DC motor controller,

said transformer further comprising a second secondary winding driving a second output providing a stable voltage to the DC motor controller.

2. A circuit according to claim 1, wherein the second secondary winding is tied to said lower DC power supply rail such that the effective voltage output of the second output is the sum of the voltage due to said secondary winding and the voltage at said lower DC power supply rail.

3. A circuit according to claim 1, wherein said driver circuitry driving said first set of n-type FETs comprises an array of switching transistors and voltage dividers.