Abstract: A method is provided for detecting a stall condition in a stepping motor. The stepping motor has two coils and a rotor, and is micro-stepped by substantially continuously driving both of the two coils with out-of-phase time varying voltages. The method includes stepping the stepping motor to a next micro-step. It is then determined when a predetermined motor parameter of a first coil of the two coils is to be sampled. To sample the predetermined motor parameter of, for example, the first coil, the first coil is opened for a predetermined period, wherein the predetermined period is less than or equal to a micro-step. Then the first coil is sampled during the predetermined period and the result of sampling is integrated and used to increment or decrement an accumulated value. If the accumulated value is less than a preset value, then a stall condition exists.

Abstract: A method is provided for detecting a stall condition in a stepping motor. The stepping motor has two coils and a rotor, and is micro-stepped by substantially continuously driving both of the two coils with out-of-phase time varying voltages. The method includes stepping the stepping motor to a next micro-step. It is then determined when a predetermined motor parameter of a first coil of the two coils is to be sampled. To sample the predetermined motor parameter of, for example, the first coil, the first coil is opened for a predetermined period, wherein the predetermined period is less than or equal to a micro-step. Then the first coil is sampled during the predetermined period and the result of sampling is integrated and used to increment or decrement an accumulated value. If the accumulated value is less than a preset value, then a stall condition exists.

Abstract: Provided herewith is an improved scheme for parking a load such as an indicator pointer and calibrating its position in a system for controlling the position of the load. The system also has a stopper for physically impeding the load when it is to be parked. In one embodiment, a parking method involves driving the motor in a reduced torque mode to move the load toward the stopper, stopping the load at the stopper while the motor is driven in the reduced torque mode, and maintaining the motor in a reduced torque mode until transitioning to an insignificant torque mode.

Abstract: In one embodiment, the invention involves a method for controlling a stepper motor. The method includes creating an information set that defines a first acceleration profile of a stepper motor and a first deceleration profile of the stepper motor; and directing the stepper motor to follow either a second acceleration profile or a second deceleration profile after the stepper motor begins to follow either the first acceleration profile or the first deceleration profile. In another embodiment, the invention is a stepper motor controller that includes a circuit configured to store an information set that defines a first acceleration profile of a stepper motor and a first deceleration profile of the stepper motor; and direct the stepper motor to follow either a second acceleration profile or a second deceleration profile after the stepper motor begins to follow either the first acceleration profile or the first deceleration profile.

Abstract: In one embodiment, the invention involves a method for controlling a stepper motor. The method includes creating an information set that defines a first acceleration profile of a stepper motor and a first deceleration profile of the stepper motor; and directing the stepper motor to follow either a second acceleration profile or a second deceleration profile after the stepper motor begins to follow either the first acceleration profile or the first deceleration profile. In another embodiment, the invention is a stepper motor controller that includes a circuit configured to store an information set that defines a first acceleration profile of a stepper motor and a first deceleration profile of the stepper motor; and direct the stepper motor to follow either a second acceleration profile or a second deceleration profile after the stepper motor begins to follow either the first acceleration profile or the first deceleration profile.

Abstract: An electric motor (101) is driven with a sequence of drive pulses (V.sub.151, V.sub.153, V.sub.155) applied to its coils (131-135). The drive pulse widths are computed over a series of time periods (T.sub.DRIVE) by a pulse generator (119) to form envelopes approximating the phase voltages (VE.sub.151, VE.sub.153, VE.sub.155) of the coils to produce sinusoidal coil currents (I.sub.131, I.sub.133, I.sub.135). A sensing circuit (137, 123) monitors the phase of the coil current with respect to phase voltage to compute a representative control signal (CONTROL). The phase has one polarity when the motor is delivering power from a battery to a load and the opposite polarity when power is delivered from the load to the battery. When the direction of transferred power changes, the control signal changes and the pulse generator switches on-the-fly to another sequence of drive pulses.