System and method for controlling motor speed using a biased pulse width modulated drive signal
First Claim
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1. A motor drive circuit, comprising:
- a switching circuit including an input node adapted to receive a drive signal and a control node adapted to receive a control signal, the switching circuit operable to couple the input node to an output node responsive to the control signal;
a bias element adapted to receive an input signal and coupled to the output node of the switching circuit, the bias element operable to automatically develop a bias voltage on the output node responsive to the input signal.
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Abstract
A motor drive circuit includes a switching circuit having an input node that receives a drive signal and a control node that receives a control signal. The switching circuit couples the input node to an output node responsive to the control signal. A bias element receives an input signal and is coupled to the output node of the switching circuit. The bias element automatically develops a bias voltage on the output responsive to the input signal. The drive circuit may be used, for example, in a motor control system to control the speed of a DC motor, such as in a power supply for a computer system.
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Citations
25 Claims
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1. A motor drive circuit, comprising:
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a switching circuit including an input node adapted to receive a drive signal and a control node adapted to receive a control signal, the switching circuit operable to couple the input node to an output node responsive to the control signal; a bias element adapted to receive an input signal and coupled to the output node of the switching circuit, the bias element operable to automatically develop a bias voltage on the output node responsive to the input signal. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8)
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9. A motor drive circuit, comprising:
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at least one an inductor having a first terminal adapted to receive a drive signal and having a second terminal; a switching circuit having an input node coupled to the second terminal, an output node, and a control node; at least one filtering capacitor coupled between a reference voltage source and the input node of the switching circuit; a bias element coupled between the input and control nodes of the switching circuit; a zener diode coupled between the control node of the switching circuit and the reference voltage source; and at least one capacitor coupled between a reference voltage source and the output node of the switching circuit. - View Dependent Claims (10, 11)
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12. A motor drive circuit, comprising:
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means for providing a motor drive signal on an output node responsive to a control signal; and means for automatically developing a bias voltage on the output node responsive to an input signal and independent of the control signal. - View Dependent Claims (13, 14, 15)
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16. A motor control system, comprising:
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a motor drive circuit, including, a switching circuit including an input node adapted to receive a drive signal and a control node adapted to receive a control signal, the switching circuit operable to couple the input node to an output node responsive to the control signal; a bias element adapted to receive an input signal and coupled to the output node of the switching circuit, the bias element operable to automatically develop a bias voltage on the output node responsive to the input signal; and a motor controller coupled to input node of the switching circuit, the motor controller operable to apply the control signal to develop a motor control signal on the output node of the switching circuit. - View Dependent Claims (17, 18, 19, 20, 21)
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22. A computer system, comprising:
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computer circuitry including memory that is operable to execute programming instructions to perform various computing functions; at least one input device coupled to the computer circuitry; at least one output device coupled to the computer circuitry; and a power supply system coupled to at least one of the computer circuitry and input and output devices, the power supply system operable to provide electrical power to the computer circuitry and devices and including, a motor drive circuit, including, a switching circuit including an input node adapted to receive a drive signal and a control node adapted to receive a control signal, the switching circuit operable to couple the input node to an output node responsive to the control signal; a bias element adapted to receive an input signal and coupled to the output node of the switching circuit, the bias element operable to automatically develop a bias voltage on the output node responsive to the input signal; and a motor controller coupled to input node of the switching circuit, the motor controller operable to apply the control signal to develop a motor control signal on the output node of the switching circuit; and a DC motor coupled to the output node and the motor control signal having a characteristic adjusted by the motor controller to control a speed of the motor. - View Dependent Claims (23, 24, 25)
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Specification