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US 6,479,954 B1Granted
Control and drive system for a single winding electromagnetic actuator employing a single multifunction operational amplifier
AssigneeSTMicroelectronics S.r.l.
InventorsRoberto Peritore, Andrea Merello, Gianluca Ventura
Life of this patent
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Abstract
A system for controlling and driving an electromagnetic actuator includes a unique operational amplifier in the regulation loop for driving the electromagnetic actuator and for monitoring, during different phases of operation, the current in the actuator and the back electromotive force. The new architecture allows for a considerable reduction of the area of integration of the system as a whole.
Claims41
A system for controlling and driving an actuator comprising:
- a current sensing resistance to be connected in series with the actuator;
- a pair of power stages connected to said current sensing resistance and to the actuator for driving the actuator in a bridge configuration;
- an operational amplifier for monitoring current forced in a winding of the actuator;
- and
- a control circuit connected between an output of said operational amplifier and said pair of power stages;
- said operational amplifier comprising
- a first differential input stage having a noninverting input coupled to a reference voltage and an inverting input coupled to the output of said operational amplifier for forming a transconductance feedback loop, and
- a second differential input stage connected in parallel to said first differential input stage and having a noninverting input and an inverting input respectively switchable between terminals of said current sensing resistance during a driving phase, and outputs of said pair of power stages during a phase of momentary interruption of the driving for sensing a zero-crossing of the back electromotive force (BEMF).
5 more elements
A system for controlling and driving an actuator comprising:
- a current sensor connected in series to the actuator;
- a pair of power stages connected to said current sensor and to the actuator for driving the actuator;
- an operational amplifier for monitoring current forced in a winding of the actuator;
- and
- a control circuit connected between an output of said operational amplifier and said pair of power stages;
- said operational amplifier comprising
- a first differential input stage having a first input coupled to a reference voltage and a second input coupled to the output of said operational amplifier for forming a feedback loop, and
- a second differential input stage connected in parallel to said first differential input stage and having a first input and a second input respectively switchable between terminals of said current sensor, and outputs of said pair of power stages.
5 more elements
A system for controlling and driving an actuator comprising:
- a current sensing resistance to be connected in series with the actuator;
- a pair of power stages connected to said current sensing resistance and to the actuator for driving the actuator in a bridge configuration;
- an operational amplifier for monitoring current forced in a winding of the actuator;
- and
- a control circuit connected between an output of said operational amplifier and said pair of power stages;
- said operational amplifier comprising
- a first differential input stage having a noninverting input coupled to a reference voltage and an inverting input coupled to the output of said operational amplifier for forming a transconductance feedback loop,
- a second differential input stage connected in parallel to said first differential input stage and having a noninverting input and an inverting input connected to terminals of said current sensing resistance during a driving phase,
- a third differential input stage connected in parallel to said first differential input stage and having a noninverting input and an inverting input connected to outputs of said pair of power stages during a phase of momentary interruption of the driving for sensing a zero-crossing of the back electromotive force (BEMF), and
- a pair of path selectors for switching said second and third differential input stage in parallel to said first differential input stage during respective phases of operation.
7 more elements
A system for controlling and driving an actuator comprising:
- a current sensor connected in series to the actuator;
- a pair of power stages connected to said current sensor resistance and to the actuator for driving the actuator;
- an operational amplifier for monitoring current forced in a winding of the actuator;
- and
- a control circuit connected between an output of said operational amplifier and said pair of power stages;
- said operational amplifier comprising
- a first differential input stage having a first input coupled to a reference voltage and a second input coupled to the output of said operational amplifier for forming a feedback loop,
- a second differential input stage connected in parallel to said first differential input stage and having a first input and a second input connected to terminals of said current sensor,
- a third differential input stage connected in parallel to said first differential input stage and having a first input and a second input connected to outputs of said pair of power stages, and
- a pair of path selectors for switching said second and third differential input stage in parallel to said first differential input stage during respective phases of operation.
7 more elements
A method for controlling and driving an actuator comprising:
- sensing current conducting in the actuator using a current sensor;
- driving the actuator in a bridge configuration using a pair of power stages connected to the current sensor and to the actuator;
- and
- monitoring current forced in a winding of the actuator using an operational amplifier, the monitoring comprising
- using a feedback loop formed by a first differential input stage having a first input coupled to a reference voltage and a second input coupled to the output of the operational amplifier, and
- respectively switching a first input and a second input of a second differential input stage connected in parallel to the first differential input stage between terminals of the current sensor, and outputs of the pair of power stages.
3 more elements
A method for controlling and driving an actuator comprising:
- sensing current conducting in the actuator using a current sensor;
- driving the actuator in a bridge configuration using a pair of power stages connected to the current sensor and to the actuator;
- and
- monitoring current forced in a winding of the actuator using an operational amplifier, the monitoring comprising
- using a feedback loop formed by a first differential input stage having a first input coupled to a reference voltage and a second input coupled to the output of the operational amplifier, and
- respectively switching a first input and a second input of a second differential input stage connected in parallel to the first differential input stage to terminals of the current sensing resistance, and switching a first input and a second input of a third differential input stage connected in parallel to the first differential input stage to outputs of the pair of power stages.
3 more elements
Dependencies are inferred from the claim text.