H-bridge push-pull excitation circuit for a transformer-based measuring device
AssigneeMicrochip Technology Incorporated
InventorsHalil Alper Onay, Laurence Egan
Life of this patent
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Abstract
An excitation circuit is provided for a transformer-based measuring device that includes an excitation coil. The excitation circuit includes an H-bridge circuit and a compensation circuit. The H-bridge circuit is to convert a unipolar square wave signal to a bipolar square wave signal to drive the excitation coil. The H-bridge circuit includes push-pull amplifiers arranged in two legs. The compensation circuit is coupled between the two legs of the H-bridge circuits, and compensates for any distortion in the bipolar square wave signal caused by the excitation coil as an inductive load on the H-bridge circuit.
Claims26
A position sensor comprising:
- a transformer-based measuring device connected to an object that is movable, the transformer-based measuring device comprising an excitation coil and a plurality of sensing coils;
- and
- an excitation circuit to convert a unipolar square wave signal to a bipolar square wave signal to drive the excitation coil to generate an alternating magnetic field and induce output signals in the plurality of sensing coils that vary according to a position of the object, the excitation circuit comprising:
- an H-bridge circuit comprising push-pull amplifiers arranged in two legs, the H-bridge circuit to convert the unipolar square wave signal to the bipolar square wave signal;
- a compensation circuit having a single resistor and a single capacitor coupled in series between outputs of a first of the push-pull amplifiers and a second of the push-pull amplifiers of the H-bridge circuit, the compensation circuit to compensate for inductive lag in current in the push-pull amplifiers, wherein the lag causes distortion in the bipolar square wave signal caused by the excitation coil as an inductive load on the H-bridge circuit;
- and
- a voltage buffer to transfer the bipolar square wave signal from the H-bridge circuit to the compensation circuit.
An excitation circuit comprising:
- an H-bridge circuit to convert a unipolar square wave signal to a bipolar square wave signal to drive an excitation coil of a transformer-based measuring device, the H-bridge circuit comprising push-pull amplifiers arranged in two legs;
- a compensation circuit having a single resistor and a single capacitor coupled in series between outputs of a first of the push-pull amplifiers and a second of the push-pull amplifiers of the H-bridge circuit, the compensation circuit to compensate for inductive lag in current in the push-pull amplifiers, wherein the lag causes distortion in the bipolar square wave signal caused by the excitation coil as an inductive load on the H-bridge circuit;
- and
- a voltage buffer to transfer the bipolar square wave signal from the H-bridge circuit to the compensation circuit.
A method comprising:
- converting a unipolar square wave signal to a bipolar square wave signal to drive an excitation coil, converting the unipolar square wave signal comprising:
- applying the unipolar square wave signal to an H-bridge circuit with push-pull amplifiers arranged in two legs, the H-bridge circuit converting the unipolar square wave signal to the bipolar square wave signal;
- transferring the bipolar square wave signal from the H-bridge circuit to a compensation circuit through a voltage buffer;
- and
- compensating for inductive lag in current in the push-pull amplifiers causing distortion in the bipolar square wave signal caused by the excitation coil as an inductive load on the H-bridge circuit using the compensation circuit, wherein the compensation circuit has a single resistor and a single capacitor coupled in series between outputs of a first of the push-pull amplifiers and a second of the push-pull amplifiers of the H-bridge circuit.
Dependencies are inferred from the claim text.