MOTOR DRIVING CIRCUIT
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Abstract
A first calculation unit subtracts third digital data which indicates the minimum value of the duty ratio from first digital data which indicates the duty ratio of the PWM driving operation. A slope calculation unit generates slope data which is dependent on the temperature based upon second digital data which indicates the temperature. A second calculation unit multiplies the slope data by the output data of the first calculation unit. A third calculation unit sums the output data of the second calculation unit and the third digital data. A selector receives the output data of the third calculation unit and the third digital data, selects one data that corresponds to the sign of the output data of the first calculation unit, and outputs the data thus selected as a duty ratio control signal.
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Citations
30 Claims
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1. -18. (canceled)
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19. A semiconductor chip configured to receive a Hall signal, which comprises a first signal and a second signal that are complementary, from a Hall sensor, and to PWM (Pulse Width Modulation) drive a fan motor, the semiconductor chip comprising:
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a first terminal coupled to receive a first signal which instructs a duty ratio for a PWM driving operation; a second terminal coupled to receive a second signal indicative of temperature; a control circuit that generates a PWM signal having a duty ratio according to the first signal and the second signal and drives the fan motor based on the PWM signal. - View Dependent Claims (20, 21, 22, 23, 24)
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25. An apparatus comprising:
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a fan motor; a Hall sensor; a temperature sensor; and a semiconductor chip, wherein the semiconductor chip comprises; a first terminal and a second terminal coupled to the fan motor; a third terminal and a fourth terminal coupled to the Hall sensor; a fifth terminal coupled to receive a first signal which instructs a duty ratio for a PWM driving operation; a sixth terminal coupled to receive a second signal indicative of temperature from the temperature sensor; a control circuit that generates a PWM signal having a duty ratio according to the first signal and the second signal and drives the fan motor based on the PWM signal. - View Dependent Claims (26, 27, 28, 29, 30)
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Specification