Patent classifications
H02P8/22
Current sensing and regulation for stepper motor driver
An integrated circuit includes an H-bridge circuit having a first output node for coupling to a high-side terminal of an inductor and a second output node for coupling to a low-side terminal of the inductor. A current source is coupled in series with a current sense FET between a digital upper supply voltage and the first output node, wherein during a fast decay mode, a gate of the current sense FET is coupled to be turned on. A current-sense comparator includes a first input coupled to a sensing node between the current source and the current sense FET, a second input coupled to the lower supply voltage and an output coupled to a driver control circuit.
Current sensing and regulation for stepper motor driver
An integrated circuit includes an H-bridge circuit having a first output node for coupling to a high-side terminal of an inductor and a second output node for coupling to a low-side terminal of the inductor. A current source is coupled in series with a current sense FET between a digital upper supply voltage and the first output node, wherein during a fast decay mode, a gate of the current sense FET is coupled to be turned on. A current-sense comparator includes a first input coupled to a sensing node between the current source and the current sense FET, a second input coupled to the lower supply voltage and an output coupled to a driver control circuit.
CURRENT STATE DETERMINATION METHOD AND CIRCUIT
A current state determination method is configured to determine a state of current passing through a coil of a motor and includes: at a first time point when a high side transistor and a low side transistor are switched to a cut-off state, measuring a voltage of a node where the high side transistor, the low side transistor and the coil are coupled, so as to output a first voltage; at a second time point when the high side transistor and the low side transistor are maintained in the cut-off state, measuring the voltage of the node, so as to output a second voltage; comparing the first voltage and the second voltage to obtain a comparison result; and determining the state of the current according to the comparison result. The present disclosure also provides a current state determination circuit for performing the current state determination method.
CURRENT STATE DETERMINATION METHOD AND CIRCUIT
A current state determination method is configured to determine a state of current passing through a coil of a motor and includes: at a first time point when a high side transistor and a low side transistor are switched to a cut-off state, measuring a voltage of a node where the high side transistor, the low side transistor and the coil are coupled, so as to output a first voltage; at a second time point when the high side transistor and the low side transistor are maintained in the cut-off state, measuring the voltage of the node, so as to output a second voltage; comparing the first voltage and the second voltage to obtain a comparison result; and determining the state of the current according to the comparison result. The present disclosure also provides a current state determination circuit for performing the current state determination method.
Motor control apparatus, image reading apparatus and image forming apparatus
A motor control apparatus operable to control a motor includes a phase determiner for determining a rotational phase of a rotor of the motor, and a controller having a first control mode for controlling a driving current flowing through a winding of the motor based on a current of a predetermined magnitude, and a second control mode for controlling a driving current flowing through the winding so that a deviation between a command phase representing a target phase of the rotor and a rotational phase determined by the phase determiner is reduced. The controller executes the first control mode without executing the second control mode in a case of rotating the motor in a first direction, and executes the second control mode in a case of rotating the motor in a second direction which is a reverse direction to the first direction.
Control device
Provided is a control device for controlling an electromagnetic actuator that vibrates an operation device by driving the operation device supported by an elastic support part so as to be elastically vibrated in one direction in a vibrating direction thereof, the control device comprising: a current pulse supply unit configured to supply a driving current pulse to a coil of the electromagnetic actuator as a driving current for driving the operation device in accordance with a touch operation of the operation device, wherein the current pulse supply unit supplies the drive current pulse capable of starting the elastic vibration as a main driving current pulse, and then supplies the drive current pulse capable of adjusting attenuation period of the elastic vibration as a sub-driving current pulse.
Method and system for synchronizing a rotational eccentric mass with a magnetic resonance elastography scan
The present disclosure is directed to techniques for synchronizing a rotational eccentric mass of a gravitational transducer used for a magnetic resonance elastography acquisition with a corresponding magnetic resonance elastography scan carried out by a magnetic resonance imaging system, wherein the rotation of the eccentric mass is driven by a shaft. The method includes starting the rotation of the eccentric mass at a set vibration frequency and the magnetic resonance elastography scan at a set acquisition frequency; determining the rotational position of the shaft; defining the rotational position as first reference position; calculating further reference positions. At the start time of each subsequent acquisition period, determining the current rotational position of the shaft; comparing the determined current rotational position with the theoretically expected reference position and decreasing or increasing the rotational speed of the rotational eccentric mass based on the comparison.
Method and system for synchronizing a rotational eccentric mass with a magnetic resonance elastography scan
The present disclosure is directed to techniques for synchronizing a rotational eccentric mass of a gravitational transducer used for a magnetic resonance elastography acquisition with a corresponding magnetic resonance elastography scan carried out by a magnetic resonance imaging system, wherein the rotation of the eccentric mass is driven by a shaft. The method includes starting the rotation of the eccentric mass at a set vibration frequency and the magnetic resonance elastography scan at a set acquisition frequency; determining the rotational position of the shaft; defining the rotational position as first reference position; calculating further reference positions. At the start time of each subsequent acquisition period, determining the current rotational position of the shaft; comparing the determined current rotational position with the theoretically expected reference position and decreasing or increasing the rotational speed of the rotational eccentric mass based on the comparison.
Current sensing and regulation for stepper motor driver
An integrated circuit includes an H-bridge circuit having a first output node for coupling to a high-side terminal of an inductor and a second output node for coupling to a low-side terminal of the inductor. A current sense FET is coupled between a current source and the lower supply voltage to provide a reference current that includes a peak current limit at a sensing node. A current-sense comparator has a first input coupled to the sensing node, a second input coupled to the second output node and an output coupled to send an output signal towards a driver control circuit. A FET linear detection circuit is coupled to receive a gate voltage of an active low-side power FET and has an output coupled to enable the current-sense comparator when the active low-side power FET is operating in a linear region.
Current sensing and regulation for stepper motor driver
An integrated circuit includes an H-bridge circuit having a first output node for coupling to a high-side terminal of an inductor and a second output node for coupling to a low-side terminal of the inductor. A current sense FET is coupled between a current source and the lower supply voltage to provide a reference current that includes a peak current limit at a sensing node. A current-sense comparator has a first input coupled to the sensing node, a second input coupled to the second output node and an output coupled to send an output signal towards a driver control circuit. A FET linear detection circuit is coupled to receive a gate voltage of an active low-side power FET and has an output coupled to enable the current-sense comparator when the active low-side power FET is operating in a linear region.