摘要:
A method of preventing concurrent or quasi-concurrent commutations of a pair of phase shift modulation (PSM) drive signals of an output bridge stage driving an electrical load includes establishing a threshold level of a programmed current level to be transmitted though the electrical load. The method also includes, if the programmed current level is lower than the threshold level, enhancing a time offset between commutation edges of the pair of PSM drive signals by a minimum time.
摘要:
A method of preventing concurrent or quasi-concurrent commutations of a pair of phase shift modulation (PSM) drive signals of an output bridge stage driving an electrical load includes establishing a threshold level of a programmed current level to be transmitted though the electrical load. The method also includes, if the programmed current level is lower than the threshold level, enhancing a time offset between commutation edges of the pair of PSM drive signals by a minimum time.
摘要:
A method for sensing a back electromotive force induced in a winding of a voice coil electro-mechanical actuator controlled in a discontinuous mode by alternating conduction phases to off-phases includes sensing voltage at terminals of the winding during an off-phase The winding is driven during a conduction phase immediately preceding the off-phase to invert, during a final portion of the conduction phase before entering an off-phase, a direction of flow of the current through the winding.
摘要:
A method for sensing a back electromotive force induced in a winding of a voice coil electro-mechanical actuator controlled in a discontinuous mode by alternating conduction phases to off-phases includes sensing voltage at terminals of the winding during an off-phase The winding is driven during a conduction phase immediately preceding the off-phase to invert, during a final portion of the conduction phase before entering an off-phase, a direction of flow of the current through the winding.
摘要:
A management apparatus is described of a rotating motor and a load during power loss; the apparatus comprises a first switching circuit coupled with the rotating motor and a controller of said first switching circuit. The controller is configured to drive the first switching circuit so as to convert a back-electromotive force voltage developed in the rotating motor into a power supply voltage for the load. The first switching circuit is driven in accordance with a first duty cycle. The apparatus comprises a second switching circuit coupled with the load and driven in accordance with a second duty cycle. The controller is configured to vary said first and said second duty cycles to keep the power supply voltage for the load above or equal to a threshold voltage.
摘要:
The definition of conversion of a digital value in a PWM signal using an N-bit up/down counter is improved by increasing the dimension of the input data to N+2 bits. This is done using the two Lsb's of the N+2 input data for selecting one among three intermediate levels between two consecutive values of an N-bit dynamic, according to a predefined table of combinations. The converter may still use an N-bit comparator. The system is particularly useful in driving a multi-phase brushless DC motor with each phase-winding singularly driven through a full-bridge output stage.
摘要:
A management apparatus is described of a rotating motor and a load during power loss; the apparatus comprises a first switching circuit coupled with the rotating motor and a controller of said first switching circuit. The controller is configured to drive the first switching circuit so as to convert a back-electromotive force voltage developed in the rotating motor into a power supply voltage for the load. The first switching circuit is driven in accordance with a first duty cycle. The apparatus comprises a second switching circuit coupled with the load and driven in accordance with a second duty cycle. The controller is configured to vary said first and said second duty cycles to keep the power supply voltage for the load above or equal to a threshold voltage.
摘要:
A circuit and method for driving a brushless sensorless direct current (DC) motor (2), using the steps of: at the beginning of each phase, driving the motor in PWM mode; monitoring the duration (Tc) between successive zero-crossings of the back electromotive force (BEMF), and accordingly predicting the next zero-crossing; and before the next predicted zero-crossing, switching to a linear driving mode only until the actual zero-crossing of the BEMF.
摘要:
An integrated control and power driving system moves a read/write head carrying arm over the surface of a disk. The integrated control and power driving system is applicable to a spindle motor, a mass storage disk drive and a voice-coil motor, for example, and includes a first chip and a second chip. The first chip integrates the output power stages driving the motors, and has an interface for outputting feedback signals representing functioning conditions of the voice-coil motor and of the spindle motor, and for receiving digital control signals of the output power stages. The second chip integrates logic drive and control circuitries of the power stages and an interface for receiving the feedback signals output by the first chip, and for transmitting to the first chip the digital control signals.
摘要:
A method for estimating resistance of a DC motor for positioning read/write heads of a data storage disk is provided. The DC motor is controlled in an open-loop voltage mode through a motor controller input with a first signal for compensating positioning of the read/write heads onto the data storage disk. The first signal is generated based upon a position error signal representing a difference between a position of the read/write heads and a center of a track to be read. The method includes monitoring the first signal during a read operation of data being stored on the data storage disk, and estimating the resistance based upon spectral components of the first signal.