Abstract: An electroluminescent lamp is driven by a driving circuit that can supply an approximately sinusoidal signal, a bi-directional sawtooth signal or a single-ended sawtooth signal. Switches selectively transfer energy from a battery to an inductor and then from the inductor to the lamp. In one embodiment, the lamp voltage is compared to a reference waveform, such as a sinusoid. The switches are activated responsive to the error between the lamp voltage and reference waveform to minimize the error. The lamp can thus be driven with a closer approximation of the reference waveform.

Abstract: An electroluminescent lamp is driven by a driving circuit that can supply an approximately sinusoidal signal, a bi-directional sawtooth signal or a single-ended sawtooth signal. Switches selectively transfer energy from a battery to an inductor and then from the inductor to the lamp. In one embodiment, the lamp voltage is compared to a reference waveform, such as a sinusoid. The switches are activated responsive to the error between the lamp voltage and reference waveform to minimize the error. The lamp can thus be driven with a closer approximation of the reference waveform.

Abstract: A circuit and method are provided for automatically adjusting a commutation delay from events indicating a position of a polyphase dc motor. The circuit includes a driver to supply drive current to selected stator coils of said motor. A sequencer is connected to control the driver to apply drive current to selected motor coils to rotate the motor. Motor position detecting circuitry is connected to detect the events indicating the position of the motor. A commutation delay circuit is connected to increment the sequencer in response to the detection of the events indicating the position of the motor detected by the motor position detecting circuitry. A circuit for adjusting the delay of said commutation delay circuit between each event and each sequencer commutation provides optimum motor commutation for maximum power efficiency.According to the method, drive current is supplied to selected stator coils of said motor in predetermined commutated sequences to rotate the motor.

Abstract: A method for aligning a rotor of a brushless and sensorless DC motor, the motor having a stator with at least two coils, sets of the coils being selectively energizable by a power source connected to the motor, includes steps of energizing a first set of at least one coil of the at least two coils; generating a signal indicating whether the rotor has been rotated at a rotary speed greater than a predetermined rotary speed while the first set was energized; and when the signal indicates that the rotor has not been rotated at a rotary speed greater than the predetermined rotary speed, switching the connection between the power source and the motor and energizing a second set of at least one coil of the at least two coils.

Abstract: A circuit and method are provided for automatically adjusting a commutation delay from events indicating a position of a polyphase dc motor. The circuit includes a driver to supply drive current to selected stator coils of said motor. A sequencer is connected to control the driver to apply drive current to selected motor coils to rotate the motor. Motor position detecting circuitry is connected to detect the events indicating the position of the motor. A commutation delay circuit is connected to increment the sequencer in response to the detection of the events indicating the position of the motor detected by the motor position detecting circuitry. A circuit for adjusting the delay of said commutation delay circuit between each event and each sequencer commutation provides optimum motor commutation for maximum power efficiency.According to the method, drive current is supplied to selected stator coils of said motor in predetermined commutated sequences to rotate the motor.

Abstract: A control system for controlling a stepper motor which uses six power transistors in a single, interconnected configuration with two stepper motor field coils. Two transistors are common to both field coils of the stepper motor with two stepper motor field coils. Control circuitry for switching the six transistors allows full and half step motor positioning to be performed. Transition phases are used between steady state phases to provide accurate motor operation. The transition phases are controlled entirely within the control circuitry without a requirement for input from outside the controller.

Abstract: A starting and operating apparatus and method for a sensorless, brushless direct current motor is disclosed. During start-up, the excitation to the motor is turned off while the slope of the differential back electromotive force of the floating phases is sampled. This indicates when the proper rotation and torque of the motor is obtained. After starting the motor, the apparatus samples the slope of the back electromotive force of the floating coils and finds a zero or predetermined slope condition which has been found to be near the optimum switching point for commutation from one phase to the next. A masking circuit is included to prevent an unwanted commutation immediately after commutating to the next phase.