Motor driving circuit
First Claim
1. A semiconductor integrated circuit (IC) configured to receive a Hall signal, which comprises a first hall signal and a second hall signal that are complementary, from a Hall sensor, and to drive a fan motor, the semiconductor integrated circuit (IC) comprising:
- a first terminal coupled to receive a first signal which is pulse width modulated and which instructs a duty ratio of a PWM (Pulse Width Modulation) signal, the first signal is supplied externally;
a second terminal coupled to receive a second signal indicative of temperature from a temperature sensor;
a control circuit that generates the PWM signal having the duty ratio according to the first signal and the second signal and supplies the fan motor with a driving signal according to the PWM signal; and
a rotational speed pulse output terminal structured to output an FG signal indicative of a rotational speed of the fan motor,wherein the control circuit comprises a digital filter having a delay circuit, the digital filter receives the first signal and is structured to generate a data signal indicative of the duty ratio of the first signal,wherein the PWM signal is generated according to the data signal, andwherein the semiconductor integrated circuit (IC) further comprises;
a first A/D converter structured to convert the first hall signal which is an analog signal to a third signal which is a digital signal; and
a second A/D converter structured to convert the second hall signal which is an analog signal to a fourth signal which is a digital signal.
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Accused Products
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.
17 Citations
5 Claims
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1. A semiconductor integrated circuit (IC) configured to receive a Hall signal, which comprises a first hall signal and a second hall signal that are complementary, from a Hall sensor, and to drive a fan motor, the semiconductor integrated circuit (IC) comprising:
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a first terminal coupled to receive a first signal which is pulse width modulated and which instructs a duty ratio of a PWM (Pulse Width Modulation) signal, the first signal is supplied externally; a second terminal coupled to receive a second signal indicative of temperature from a temperature sensor; a control circuit that generates the PWM signal having the duty ratio according to the first signal and the second signal and supplies the fan motor with a driving signal according to the PWM signal; and a rotational speed pulse output terminal structured to output an FG signal indicative of a rotational speed of the fan motor, wherein the control circuit comprises a digital filter having a delay circuit, the digital filter receives the first signal and is structured to generate a data signal indicative of the duty ratio of the first signal, wherein the PWM signal is generated according to the data signal, and wherein the semiconductor integrated circuit (IC) further comprises; a first A/D converter structured to convert the first hall signal which is an analog signal to a third signal which is a digital signal; and a second A/D converter structured to convert the second hall signal which is an analog signal to a fourth signal which is a digital signal. - View Dependent Claims (2, 3, 4, 5)
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Specification