Control circuit for a brushless DC motor
First Claim
1. A monolithically integrable control circuit for a brushless DC motor comprising:
- a commutation signal source for producing motor commutation signals, the commutation signal source being controlled by rotational rotor position signals,a driver circuit controlled in accordance with the commutation signals and serving for applying driving pulses, which result in a rotating magnetic field, to the motor windings, with one driver stage being provided for each motor winding phase, anda pulse shaping circuit which effects sloping of the driving pulse edges, the pulse shaping circuit being connected to the driver circuit to provide drive control pulses thereto and additionally being connected to an external edge sloping impedance means for sloping the edges of the driver control pulses,wherein a sloped driver control pulse (VCA, VCB) for a particular motor phase is initiated substantially by the termination of a sloped driver control pulse (VCA, VCB) for the preceding motor phase, andwherein the driver stages (15) are designed as feedback-free amplifier stages, each including a source stage (Q4, Q5) supplying current into a connected motor winding, and a drain stage (Q6, Q7) receiving current from the connected motor winding, with the source stage (Q4 Q5) and the drain stage (Q6, Q7) being controllable independently of each other, with the drain stage (Q6, Q7) being designed as a switch and the source stage (Q4, Q5) having a conductive stage wherein it is controllable analogously with said sloped driver control pulse (VCA, VCB), so that the output voltage of the driver stages (15) is controllable with the sloped driver control pulses (VCA, VCB) and a voltage corresponding to said sloped river control pulse (VCA, VCB) is thus applied to the particular activated motor winding.
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Accused Products
Abstract
A monolithically integrated control circuit (4) for a brushless DC motor (1) comprising a commutation signal source (3) controlled by rotational motor position signals, a driver circuit (TS) controlled in accordance with the commutation signals and serving for applying driving pulses, which result in a rotating magnetic field, to the motor windings, with one driver stage (15A, 15B, 15C, 15D) being provided for each motor winding phase, and comprising, furthermore, a pulse shaping circuit (10) effecting sloping of the driving pulse edges, with the pulse shaping circuit (10) being arranged upstream of the driver circuit (TS) and being connected to an external edge sloping impedance means (CA, CB), and the driver stages (15A, 15B, 15C, 15D) being designed as feedback-free amplifier stages fed with driver control pulses (VCA ; VCB) that are sloped by means of the pulse shaping circuit (10).
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Citations
22 Claims
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1. A monolithically integrable control circuit for a brushless DC motor comprising:
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a commutation signal source for producing motor commutation signals, the commutation signal source being controlled by rotational rotor position signals, a driver circuit controlled in accordance with the commutation signals and serving for applying driving pulses, which result in a rotating magnetic field, to the motor windings, with one driver stage being provided for each motor winding phase, and a pulse shaping circuit which effects sloping of the driving pulse edges, the pulse shaping circuit being connected to the driver circuit to provide drive control pulses thereto and additionally being connected to an external edge sloping impedance means for sloping the edges of the driver control pulses, wherein a sloped driver control pulse (VCA, VCB) for a particular motor phase is initiated substantially by the termination of a sloped driver control pulse (VCA, VCB) for the preceding motor phase, and wherein the driver stages (15) are designed as feedback-free amplifier stages, each including a source stage (Q4, Q5) supplying current into a connected motor winding, and a drain stage (Q6, Q7) receiving current from the connected motor winding, with the source stage (Q4 Q5) and the drain stage (Q6, Q7) being controllable independently of each other, with the drain stage (Q6, Q7) being designed as a switch and the source stage (Q4, Q5) having a conductive stage wherein it is controllable analogously with said sloped driver control pulse (VCA, VCB), so that the output voltage of the driver stages (15) is controllable with the sloped driver control pulses (VCA, VCB) and a voltage corresponding to said sloped river control pulse (VCA, VCB) is thus applied to the particular activated motor winding. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16)
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17. A control circuit for a brushless DC motor having a rotor and having a plurality of motor coils which are connected in a loop at coil connection points, comprising:
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feedback means, operatively connected to the motor, for generating rotational rotor position signals; controller means, responsive to the rotational rotor position signals, for generating a commutation signal; signal processing means, responsive to the commutation signal, for generating switching control signals and at least one pulse train having substantially trapezoidally shaped driver control pulses; and driver means, responsive to the switching control signals and the at least one pulse train, for driving the motor coils to generate a rotating magnetic field within the motor, the driver means including at least one driver stage having a tri-state output port that is connected to a respective one of the coil connection points, first and second power supply ports for receiving electrical power to drive the motor, a source stage connected between the first power supply port and the output port, a drain stage connected between the second power supply port and the output port, means responsive to the switching control signals for selectively rendering the source and drain stages conductive, not more than one of the source and drain stages being substantially conductive at any time, and means for controlling the current through one of the source and drain stages when it is conductive so that the current varies as a function of the driver control pulse. - View Dependent Claims (18, 19, 20, 21, 22)
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Specification