Abstract: A motor controller for a direct current motor includes a first node receiving first PWM signals having a duty cycle indicative of a desired rotational speed of said motor and an input node receiving second digital signals, the frequency of said second signals indicative of the rotational speed of said motor. A frequency-to-PWM circuit is coupled to the input node to provide second PWM signals having a duty cycle corresponding to the rotational speed of the motor. A duty cycle comparator has a first input coupled to the first node and a second input coupled to the second node to generate a control signal for controlling the rotational speed of the motor.

Abstract: A method of operating a direct current motor fan assembly is provided in which a motor controller operates to apply full power to kick-start a motor to overcome static forces. As soon as a sensor determines that the motor has begun to rotate, the motor controller changes the motor drive level from full power to a predetermined lower level to maintain a desired rotational speed.

Abstract: A method and apparatus is provided for processing signals from a Hall-effect device arrangement coupled to a monolithic brushless DC motor where the motor is driven by a PWM circuit providing PWM drive signals.

Abstract: A duty cycle comparator is described for comparing the duty cycles of two digital signals. The duty cycle comparator comprises a first controllable current source, a second controllable current source and a charge accumulation device. The comparator provides an output signal that is representative of the difference between the duty cycles independent of the frequency of the two digital signals.

Abstract: In accordance with the principles of the invention, a semiconductor substrate is provided that has a first cell formed thereon. The first cell has first and second terminals or nodes and a control terminal or node and has a characteristic breakdown voltage across the first and second terminals. A voltage sensing transistor is coupled across the power transistor first and second terminals. The voltage sensing transistor has a second element characteristic breakdown voltage that is less than the first cell characteristic breakdown voltage. The voltage sensing transistor provides a control signal to the terminal when the voltage across the first and second terminals exceeds the second element characteristic breakdown voltage.

Abstract: A method and apparatus is provided for processing signals from a Hall-effect device arrangement coupled to a monolithic brushless DC motor where the motor is driven by a PWM circuit providing PWM drive signals.

Abstract: In accordance with the principles of the invention, an integrated circuit comprises a substrate having a first FET formed on the substrate. The first FET has a first terminal coupleable to a load, a second terminal and a control terminal. The second terminal is connected to the substrate. The substrate comprises a parasitic body diode coupled between the first terminal and the substrate. The body diode is disposed such that it becomes conductive when a reverse voltage across the FET first terminal and the substrate is at least a first diode forward voltage. A voltage detector is formed on the substrate. The voltage detector has a first input coupled to the FET first terminal, a second input coupled to the substrate, and an output coupled to the FET control terminal. The voltage detector is responsive to a reverse voltage level at the FET first terminal that is less than the first diode forward voltage to turn the FET on for the duration of a reverse voltage having at least said reverse voltage level.

Abstract: A method and apparatus is provided for processing signals from a Hall effect device arrangement coupled to a monolithic brushless DC motor where the motor is driven by a PWM circuit providing PWM drive signals.

Abstract: In accordance with the principles of the invention, a semiconductor device is provided that has a power transistor and a voltage sensing transistor formed on a substrate. The power transistor has first and second terminals and a control terminal and having a characteristic first breakdown voltage across the first and second terminals. The voltage sensing transistor is coupled across the power transistor first and second terminals. The voltage sensing transistor has a second element characteristic breakdown voltage that is less than the power transistor breakdown voltage. The second transistor provides a control signal to the power transistor control terminal when the voltage across the power transistor first and second terminals exceeds the second element characteristic breakdown voltage.

Abstract: A method and apparatus is provided for processing signals from a Hall effect device arrangement coupled to a monolithic brushless DC motor where the motor is driven by a PWM circuit providing PWM drive signals.

Abstract: A method of operating a direct current motor fan assembly is provided in which a motor controller operates to apply full power to kick-start a motor to overcome static forces. As soon as a sensor determines that the motor has begun to rotate, the motor controller changes the motor drive level from full power to a predetermined lower level to maintain a desired rotational speed.

Abstract: A control circuit for a direct current motor is described. In accordance with the principles of the invention, a duty cycle comparator is provided to control the speed of the motor.

Abstract: A duty cycle comparator is described for comparing the duty cycles of two digital signals. The duty cycle comparator comprises a first controllable current source, a second controllable current source and a charge accumulation device. The comparator provides an output signal that is representative of the difference between the duty cycles independent of the frequency of the two digital signals.

Abstract: In accordance with the principles of the invention, an integrated circuit comprises a substrate having a first FET formed on the substrate. The first FET has a first terminal coupleable to a load, a second terminal and a control terminal. The second terminal is connected to the substrate. The substrate comprises a parasitic body diode coupled between the first terminal and the substrate. The body diode is disposed such that it becomes conductive when a reverse voltage across the FET first terminal and the substrate is at least a first diode forward voltage. A voltage detector is formed on the substrate. The voltage detector has a first input coupled to the FET first terminal, a second input coupled to the substrate, and an output coupled to the FET control terminal. The voltage detector is responsive to a reverse voltage level at the FET first terminal that is less than the first diode forward voltage to turn the FET on for the duration of a reverse voltage having at least said reverse voltage level.

Abstract: In accordance with the principles of the invention, a semiconductor substrate is provided that has a first cell formed thereon. The first cell has first and second terminals or nodes and a control terminal or node and has a characteristic breakdown voltage across the first and second terminals. A voltage sensing transistor is coupled across the power transistor first and second terminals. The voltage sensing transistor has a second element characteristic breakdown voltage that is less than the first cell characteristic breakdown voltage. The voltage sensing transistor provides a control signal to the terminal when the voltage across the first and second terminals exceeds the second element characteristic breakdown voltage.

Abstract: In accordance with the principles of the invention, a semiconductor device is provided that has a power transistor and a voltage sensing transistor formed on a substrate. The power transistor has first and second terminals and a control terminal and having a characteristic first breakdown voltage across the first and second terminals. The voltage sensing transistor is coupled across the power transistor first and second terminals. The voltage sensing transistor has a second element characteristic breakdown voltage that is less than the power transistor breakdown voltage. The second transistor provides a control signal to the power transistor control terminal when the voltage across the power transistor first and second terminals exceeds the second element characteristic breakdown voltage.

Abstract: A PWM controller for a direct current brushless motor comprising first and second windings includes a motor drive circuit receiving pulse width modulation control signals to drive the first and the second windings; and a control circuit having inputs coupled to the first and second windings to control a pulse width modulation control circuit such that pulse width modulated control signals are provided to the motor drive circuit only when the voltage across the first and second windings are at a predetermined level.

Abstract: A method and apparatus of interfacing a Hall sensor to a commutation circuit comprises receiving output signals from the Hall sensor; detecting when the Hall sensor output signals are within a predetermined range; generating commutation output signals when the Hall sensor output signals are in a predetermined state for a predetermined period of time; and locking out a change in the commutation output signals for a second predetermined period of time.

Abstract: A single input pin (48) provides multi-functional features for programming a power supply (10). By connecting the appropriate interface circuit (92, 100, or 112) to the single input pin (48), the power supply (10) is programmed for specific behaviors during power up and toggling of an on/off switch (96, 108). In one mode of operation a light emitting diode (106) in the interface circuit (100) is optically coupled to a microprocessor for signaling the closure of the on/off switch (108), allowing the microprocessor to control the power supply (10) through an opto-coupler (102). In another mode of operation, the single on/off switch (96) controls the power supply (10). In yet another mode of operation, Zener diode (118) in the interface circuit (112) controls the power supply (10) during brown-out and black-out conditions.

Abstract: A single input pin (48) provides multi-functional features for programming a power supply (10). By connecting the appropriate interface circuit (92, 100, or 112) to the single input pin (48), the power supply (10) is programmed for specific behaviors during power up and toggling of an on/off switch (96, 108). In one mode of operation a light emitting diode (106) in the interface circuit (100) is optically coupled to a microprocessor for signaling the closure of the on/off switch (108), allowing the microprocessor to control the power supply (10) through an opto-coupler (102). In another mode of operation, the single on/off switch (96) controls the power supply (10). In yet another mode of operation, Zener diode (118) in the interface circuit (112) controls the power supply (10) during brown-out and black-out conditions.