Controller for a brushless direct current motor
First Claim
1. A controller for a brushless direct current motor that includes a rotor, said controller comprising:
- a power source unit for providing a direct current output;
a drive circuit coupled electrically to said power source unit and including a drive coil and a switching transistor unit coupled electrically to said drive coil, said switching transistor unit being operable in one of a circuit-making state for making an electrical circuit between said drive coil and said power source unit so as to enable said drive coil to drive rotation of the rotor, and a circuit-breaking state for breaking the electrical circuit between said drive coil and said power source unit; and
a state control circuit coupled electrically to said power source unit and including a pulse width modulator, a sensing coil, and a control transistor coupled electrically in series, said control transistor being further coupled to said switching transistor unit;
said state control circuit being operable in a first control state when the rotor is at a first magnetic position relative to said sensing coil, and in a second control state when the rotor is at a second magnetic position relative to said sensing coil;
wherein said state control circuit operates said switching transistor unit in the circuit-making state to result in continuous current flow through said drive coil when said state control circuit is operated in the first control state; and
wherein said state control circuit operates said switching transistor unit to alternate between the circuit-breaking and circuit-making states to result in intermittent current flow through said drive coil when said state control circuit is operated in the second control state.
1 Assignment
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Accused Products
Abstract
A controller includes a power source unit, a drive circuit, and a state control circuit. The drive circuit is coupled to the power source unit, and includes a drive coil and a switching transistor unit. The switching transistor unit is operable in one of a circuit-making state for making an electrical circuit between the drive coil and the power source unit so as to enable the drive coil to drive rotation of a rotor of a brushless direct current motor, and a circuit-breaking state for breaking the electrical circuit between the drive coil and the power source unit. The state control circuit is coupled to the power source unit, and includes a pulse width modulator, a sensing coil, and a control transistor coupled electrically in series. The state control circuit controls operation of the switching transistor unit according to magnetic position of the rotor relative to the sensing coil.
12 Citations
6 Claims
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1. A controller for a brushless direct current motor that includes a rotor, said controller comprising:
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a power source unit for providing a direct current output; a drive circuit coupled electrically to said power source unit and including a drive coil and a switching transistor unit coupled electrically to said drive coil, said switching transistor unit being operable in one of a circuit-making state for making an electrical circuit between said drive coil and said power source unit so as to enable said drive coil to drive rotation of the rotor, and a circuit-breaking state for breaking the electrical circuit between said drive coil and said power source unit; and a state control circuit coupled electrically to said power source unit and including a pulse width modulator, a sensing coil, and a control transistor coupled electrically in series, said control transistor being further coupled to said switching transistor unit; said state control circuit being operable in a first control state when the rotor is at a first magnetic position relative to said sensing coil, and in a second control state when the rotor is at a second magnetic position relative to said sensing coil; wherein said state control circuit operates said switching transistor unit in the circuit-making state to result in continuous current flow through said drive coil when said state control circuit is operated in the first control state; and wherein said state control circuit operates said switching transistor unit to alternate between the circuit-breaking and circuit-making states to result in intermittent current flow through said drive coil when said state control circuit is operated in the second control state. - View Dependent Claims (2, 3, 4, 5, 6)
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Specification