Abstract: A method to reduce acoustic noise in a cooling fan motor is disclosed. The method includes reducing the slew rate of a PWM (pulse width modulation) voltage waveform applied to energize a coil of the fan motor. This slew rate reduction results in lower mechanical vibrations and acoustic noise in the fan motor. In one embodiment, the slew rate reduction is performed during startup of the fan motor, when the motor is spinning slowly and there is little air flow noise. In another embodiment, the slew rate reduction is not performed during high speed operation of the fan motor, when the fan motor is spinning very fast and air flow noise masks the motor noise. In one embodiment, there is variable slew rate control depending on the speed of the fan motor.

Abstract: A fan assembly having a reduced dimension formed by several modifications is described. The fan assembly includes a stator having stator coils positioned within a recessed portion of a pillow that receives the motor. The stator may include wire connections positioned between adjacent stator coils and designed to terminate wires of the stator coils. The wire terminations may be on a protrusion or a post positioned between adjacent stator coils, or alternatively, the wire terminations may be disposed on protruding features of a bushing. The protrusion may be formed from an electrically conductive material and electrically connected to a motor control circuit via a flexible printed circuit. In some embodiments, the protrusion is part of an electrically neutral stator bushing having several pins. Also, a gap region between the bushing and a flange feature is designed to improve an adhesive joint.

Abstract: A fan assembly having a reduced dimension formed by several modifications is described. The fan assembly includes a stator having stator coils positioned within a recessed portion of a pillow that receives the motor. The stator may include wire connections positioned between adjacent stator coils and designed to terminate wires of the stator coils. The wire terminations may be on a protrusion or a post positioned between adjacent stator coils, or alternatively, the wire terminations may be disposed on protruding features of a bushing. The protrusion may be formed from an electrically conductive material and electrically connected to a motor control circuit via a flexible printed circuit. In some embodiments, the protrusion is part of an electrically neutral stator bushing having several pins. Also, a gap region between the bushing and a flange feature is designed to improve an adhesive joint.

Abstract: One embodiment of a display backlight driver integrated circuit can be configured for operation in at least two different ways. A first method transfers data from an EEPROM to hardware registers prior to regular operation. A second method also transfers data from an EEPROM to registers. However, hardware registers can be overwritten with data accepted from a control bus, prior to regular operation. A keyboard driver IC can detect the presence or absence of a cable to an LED. If the cable is absent, the driver IC will not supply power for the LED. One embodiment of a keyboard and display backlight control system can be configured to allow substantially independent operation.

Abstract: One embodiment of a display backlight driver integrated circuit can be configured for operation in at least two different ways. A first method transfers data from an EEPROM to hardware registers prior to regular operation. A second method also transfers data from an EEPROM to registers. However, hardware registers can be overwritten with data accepted from a control bus, prior to regular operation. A keyboard driver IC can detect the presence or absence of a cable to an LED. If the cable is absent, the driver IC will not supply power for the LED. One embodiment of a keyboard and display backlight control system can be configured to allow substantially independent operation.

Abstract: A method to reduce acoustic noise in a cooling fan motor is disclosed. The method includes reducing the slew rate of a PWM (pulse width modulation) voltage waveform applied to energize a coil of the fan motor. This slew rate reduction results in lower mechanical vibrations and acoustic noise in the fan motor. In one embodiment, the slew rate reduction is performed during startup of the fan motor, when the motor is spinning slowly and there is little air flow noise. In another embodiment, the slew rate reduction is not performed during high speed operation of the fan motor, when the fan motor is spinning very fast and air flow noise masks the motor noise. In one embodiment, there is variable slew rate control depending on the speed of the fan motor.

Abstract: One embodiment of a display backlight driver integrated circuit can be configured for operation in at least two different ways. A first method transfers data from an EEPROM to hardware registers prior to regular operation. A second method also transfers data from an EEPROM to registers. However, hardware registers can be overwritten with data accepted from a control bus, prior to regular operation. A keyboard driver IC can detect the presence or absence of a cable to an LED. If the cable is absent, the driver IC will not supply power for the LED. One embodiment of a keyboard and display backlight control system can be configured to allow substantially independent operation.

Abstract: One embodiment of a display backlight driver integrated circuit can be configured for operation in at least two different ways. A first method transfers data from an EEPROM to hardware registers prior to regular operation. A second method also transfers data from an EEPROM to registers. However, hardware registers can be overwritten with data accepted from a control bus, prior to regular operation. A keyboard driver IC can detect the presence or absence of a cable to an LED. If the cable is absent, the driver IC will not supply power for the LED. One embodiment of a keyboard and display backlight control system can be configured to allow substantially independent operation.

Abstract: The described embodiments relate generally to control of rotational components in a computer system. In one embodiment, the rotational component includes a cooling fan assembly, the cooling fan assembly being controlled in accordance with resonant frequency avoidance data. The resonant frequency avoidance data being characteristic of the computer system such that when the cooling fan assembly operates in accordance with the resonant frequency avoidance data, the cooling fan assembly does not operate at a fan speed that is coincident with a natural resonant frequency of the computer system.

Abstract: The described embodiments relate generally to control of rotational components in a computer system. In one embodiment, the rotational component includes a cooling fan, the cooling fan being controlled in accordance with data tailored to reduce the acoustic noise produced by the cooling fan. In one embodiment, the cooling fan is operated with non-uniform pulse width modulated signals. The non-uniform pulse width modulated signals can be a function of desired rotation speed and can include fundamental and harmonic components.