Abstract: An embodiment of a motor controller includes first and second supply nodes, a motor-coil node, an isolator, a motor driver, and a motor position signal generator. The isolator is coupled between the first and second supply nodes, and the motor driver is coupled to the second supply node and to the motor-coil node. The motor position signal generator is coupled to the isolator and is operable to generate, in response to the isolator, a motor-position signal that is related to a position of a motor having at least one coil coupled to the motor-coil node. By generating the motor-position signal in response to the isolator, the motor controller or another circuit may determine the at-rest or low-speed position of a motor without using an external coil-current-sense circuit.

Abstract: An embodiment of a motor controller includes first and second supply nodes, a motor-coil node, an isolator, a motor driver, and a motor position signal generator. The isolator is coupled between the first and second supply nodes, and the motor driver is coupled to the second supply node and to the motor-coil node. The motor position signal generator is coupled to the isolator and is operable to generate, in response to the isolator, a motor-position signal that is related to a position of a motor having at least one coil coupled to the motor-coil node. By generating the motor-position signal in response to the isolator, the motor controller or another circuit may determine the at-rest or low-speed position of a motor without using an external coil-current-sense circuit.

Abstract: An embodiment of a motor controller includes first and second supply nodes, a motor-coil node, an isolator, a motor driver, and a motor position signal generator. The isolator is coupled between the first and second supply nodes, and the motor driver is coupled to the second supply node and to the motor-coil node. The motor position signal generator is coupled to the isolator and is operable to generate, in response to the isolator, a motor-position signal that is related to a position of a motor having at least one coil coupled to the motor-coil node. By generating the motor-position signal in response to the isolator, the motor controller or another circuit may determine the at-rest or low-speed position of a motor without using an external coil-current-sense circuit.

Abstract: A current sensing circuit for a pulse width modulation (PWM) application may include first and second input terminals to be coupled to ends of a sensing resistance, an output terminal, and first and second internal circuit nodes. The current sensing circuit further may include an input block comprising a first transconductance amplifier to be coupled to a supply voltage. The first transconductance amplifier may be coupled to the first and second input terminals and to the first and second internal circuit nodes. The current sensing circuit may also include an amplifier block comprising an amplifier to be coupled to a reference voltage, and coupled to the first and second internal circuit nodes and the output terminal, and a feedback block comprising a second transconductance amplifier to be coupled to the supply voltage and being coupled to the output terminal and the first and second internal circuit nodes.

Abstract: A current sensing circuit for a pulse width modulation (PWM) application may include first and second input terminals to be coupled to ends of a sensing resistance, an output terminal, and first and second internal circuit nodes. The current sensing circuit further may include an input block comprising a first transconductance amplifier to be coupled to a supply voltage. The first transconductance amplifier may be coupled to the first and second input terminals and to the first and second internal circuit nodes. The current sensing circuit may also include an amplifier block comprising an amplifier to be coupled to a reference voltage, and coupled to the first and second internal circuit nodes and the output terminal, and a feedback block comprising a second transconductance amplifier to be coupled to the supply voltage and being coupled to the output terminal and the first and second internal circuit nodes.

Abstract: An embodiment of a motor controller includes first and second supply nodes, a motor-coil node, an isolator, a motor driver, and a motor position signal generator. The isolator is coupled between the first and second supply nodes, and the motor driver is coupled to the second supply node and to the motor-coil node. The motor position signal generator is coupled to the isolator and is operable to generate, in response to the isolator, a motor-position signal that is related to a position of a motor having at least one coil coupled to the motor-coil node. By generating the motor-position signal in response to the isolator, the motor controller or another circuit may determine the at-rest or low-speed position of a motor without using an external coil-current-sense circuit.

Abstract: An apparatus is provided for powering at least one electric motor. The apparatus includes at least one driving device for driving the electric motor, a supply path positioned between a supply voltage generator and the at least one driving device, a first circuit, a control device, and a protection device for protecting against over-voltages. The first circuit is inserted in the supply path to enable and prevent the powering of the at least one driving device, and the control device controls at least the first circuit. The protection device includes a second circuit for detecting a current that flows in the supply path from the at least one driving device to the supply voltage generator, and a third circuit for selectively absorbing the current that is detected.

Abstract: An apparatus is provided for powering at least one electric motor. The apparatus includes at least one driving device for driving the electric motor, a supply path positioned between a supply voltage generator and the at least one driving device, a first circuit, a control device, and a protection device for protecting against over-voltages. The first circuit is inserted in the supply path to enable and prevent the powering of the at least one driving device, and the control device controls at least the first circuit. The protection device includes a second circuit for detecting a current that flows in the supply path from the at least one driving device to the supply voltage generator, and a third circuit for selectively absorbing the current that is detected.

Abstract: A circuit estimates speed of an electromagnetic actuator associated with a reading head of a disk storage unit and a digital controller. The circuit includes first and second supply terminals and an output terminal, with the first supply terminal being connected to the electromagnetic actuator. A measuring resistor is connected to the second supply terminal, and is connected in series with the electromagnetic actuator for measuring a current which passes therethrough when a supply voltage is applied between the first and second supply terminals. An adder has an output connected to the output terminal for providing an output voltage, a first input is connected to the first supply terminal, and a second input is connected to the second supply terminal. An adjustable-gain amplifier is connected between the measuring resistor and the second input of the adder for transferring the supply voltage and a voltage across the measuring resistor to the adder.

Abstract: The present invention herein describes a tracking analog-to-digital converter, in particular of the differential input type. In an embodiment thereof the tracking analog-to-digital converter, having a differential analog input including a first analog input and a second analog input, and a digital output at a first number of bits comprising: a back and forth counter having a direction input and an output, with a second number of bits; a digital-to-analog converter having a data input coupled to said output of said converter, a reference input and an output, with a second number of bits; a first comparator having a positive input, a negative input coupled to said output of said digital-to-analog converter and an output coupled to said direction input; characterized in that said reference input is coupled to said first analog input and said positive input of said first comparator is coupled to said second analog input.

Abstract: A circuit for the speed recovery of a direct current motor includes an output stage, output stage having a first pair of transistors, a second pair of transistors, and means a first circuit configured to detect a current circulating in the motor. The output stage further includes a second circuit configured to, activate the second pair transistors for a determined first time period so as to short-circuit the motor, and, at the end of the first time period, unbalance the output stage so as to force a maximum current to circulate for a determined second time period as a function of a value detected by the first circuit during the first time period, so as to stop the motor.

Abstract: A control circuit providing a driving current to a voice coil motor to position a reading and writing head of a disk memory system is described. The circuit comprises a first and a second class AB amplifiers the outputs of which are connected to the terminals of a first resistor in series with the voice coil motor so that a current passes through the voice coil motor and through the first resistor. The circuit comprises a sense amplifier the input terminals of which are coupled with the terminals of said first resistor, a device at the input of which is present a signal which is a sum of an external signal and of an output signal of the sense amplifier. The first amplifier and the second amplifier being driven in inverted phase by an output signal produced by the device.

Abstract: The present invention herein describes a tracking analog-to-digital converter, in particular of the differential input type.

Abstract: A circuit estimates speed of an electromagnetic actuator associated with a reading head of a disk storage unit and a digital controller. The circuit includes first and second supply terminals and an output terminal, with the first supply terminal being connected to the electromagnetic actuator. A measuring resistor is connected to the second supply terminal, and is connected in series with the electromagnetic actuator for measuring a current which passes therethrough when a supply voltage is applied between the first and second supply terminals. An adder has an output connected to the output terminal for providing an output voltage, a first input is connected to the first supply terminal, and a second input is connected to the second supply terminal. An adjustable-gain amplifier is connected between the measuring resistor and the second input of the adder for transferring the supply voltage and a voltage across the measuring resistor to the adder.

Abstract: A positioning system for a read/write head of a disk drive includes a rotatable data disk, a read/write head movable over the disk, a voice coil motor (VCM) connected to the head and a source of digital position signals. A control circuit includes means for generating a VCM control current, a sensor for sensing the VCM current and an amplifier having an inverting input connected to a reference voltage source through a resistor and to a sensor output, a non-inverting input connected to the source of digital position signals through a DAC and an output connected to an input of the drive means.

Abstract: A circuit for the speed recovery of a direct current motor comprises an output stage, that includes a first couple of transistors and a second couple of transistors, and first means, for detecting a current circulating in said motor. The circuit has the characteristic of comprising second means, suitable for activating said second couple of transistors of said output stage for a determined first time period so as to short-circuit said motor, and at the end of said first time period said second means being suitable for unbalancing said output stage so as to force the maximum current circulating for a determined second time period in function of the value detected by said first means during said first time period so as to stop said motor.

Abstract: A feedback control circuit is for the current in a load formed by a winding in series with a current sensing resistor, coupled to a full-bridge output stage, an amplifier coupled to the terminals of the sensing resistor, and a controller fed with the output of the amplifier and with a voltage reference and producing a correction signal. The circuit has a PWM converter for generating a pair of control signals. The PWM converter includes an up/down counter producing a count value and logic circuitry that produces the twos-complement of the correction signal. A pair of registers are coupled to the outputs of the controller and of the logic circuitry. A first comparator coupled to the outputs of the counter and of the first register produces the first control signal, if the count signal exceeds the value stored in the first register. A second comparator coupled to the counter and to the second register produces the second control signal, if the count signal overcomes the value stored in the second register.

Abstract: A control circuit providing a driving current to a voice coil motor to position a reading and writing head of a disk memory system is described. The circuit comprises a first and a second class AB amplifiers the outputs of which are connected to the terminals of a first resistor in series with the voice coil motor so that a current passes through the voice coil motor and through the first resistor. The circuit comprises a sense amplifier the input terminals of which are coupled with the terminals of said first resistor, a device at the input of which is present a signal which is a sum of an external signal and of an output signal of the sense amplifier. The first amplifier and the second amplifier being driven in inverted phase by an output signal produced by the device.

Abstract: A feedback control circuit is for the current in a load formed by a winding in series with a current sensing resistor, coupled to a full-bridge output stage, an amplifier coupled to the terminals of the sensing resistor, and a controller fed with the output of the amplifier and with a voltage reference and producing a correction signal. The circuit has a PWM converter for generating a pair of control signals. The PWM converter includes an up/down counter producing a count value and logic circuitry that produces the twos-complement of the correction signal. A pair of registers are coupled to the outputs of the controller and of the logic circuitry. A first comparator coupled to the outputs of the counter and of the first register produces the first control signal, if the count signal exceeds the value stored in the first register. A second comparator coupled to the counter and to the second register produces the second control signal, if the count signal overcomes the value stored in the second register.

Abstract: A method drives a three-phase motor having first, second, and third coils. The method electrically connects the first coil to a first voltage reference and the second coil to a second voltage reference while leaving the other coil floating during a first driving phase. During a second driving phase, the first coil is electrically connected to the first voltage reference and the third coil is electrically connected to the second voltage reference while the second coil is left floating. During a transition phase that immediately follows the fast driving phase and immediately precedes the second driving phase, the second coil is electrically connected alternately to the first and second voltage references. By alternately connecting the second coil to the first second voltage references and during the transition phase, the method causes the current through the second coil to reduce to zero at a slower rate than prior methods.