Circuit for biasing an external resistive sensor
AssigneeSTMicroelectronics S.r.l.
InventorsDario Livornesi, Mattia Fausto Moretti, Paolo Pulici, Alessio Emanuele Vergani, Alessio Facen, Michele Bartolini, Roberto Faravelli, Francesco Piscitelli
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Abstract
According to an embodiment, a circuit includes a core and low-frequency recovery circuits. The core circuit is configured to bias a resistive sensor used to measure a fly height of a hard disk drive. The core circuit is additionally configured to amplify a high-frequency component of a sensing signal of the resistive sensor, the sensing signal indicating the fly height. The low-frequency recovery circuit is configured to amplify the sensing signal's low-frequency component.
Claims20
A circuit comprising:
- a core circuit configured to:
- bias a resistive sensor, the resistive sensor configured to measure a fly height of a hard disk drive, and
- amplify a high-frequency component of a sensing signal of the resistive sensor, the sensing signal indicating the fly height;
- and
- a low-frequency recovery circuit configured to amplify a low-frequency component of the sensing signal.
A circuit comprising:
- a core circuit comprising:
- a pair of amplifiers,
- a voltage-biasing digital-to-analog converter,
- a first pair of transistors having control terminals coupled to the voltage-biasing digital-to-analog converter,
- a second pair of transistors having control terminals coupled to a respective one of the pair of amplifiers,
- a resistive sensor coupled to the second pair of transistors, and
- a first pair of resistors coupled to the second pair of transistors;
- and
- a low-frequency recovery circuit comprising:
- a current offset digital-to-analog converter,
- a third pair of transistors having control terminals coupled to a respective one of the pair of amplifiers, and
- a second pair of resistors coupled to the current offset digital-to-analog converter and the third pair of transistors.
A circuit comprising:
- a core circuit comprising:
- a pair of amplifiers,
- a current biasing digital-to-analog converter,
- a first pair of transistors having control terminals coupled to the current biasing digital-to-analog converter,
- a second pair of transistors having control terminals coupled to a respective one of the pair of amplifiers, the second pair of transistors set such that a current flowing through each is constant and equal to an expected current,
- a resistive sensor coupled to the first pair of transistors and biased in accordance with the expected current, and
- a first pair of resistors coupled to the second pair of transistors;
- a first low-frequency recovery circuit comprising:
- a first common resistor,
- a third pair of transistors, wherein a first set of terminals of the third pair of transistors is coupled to terminals of the first common resistor, and wherein a control terminal of each of the third pair of transistors is coupled to a respective one of the pair of amplifiers and a respective control terminal of an associated transistor of the second pair of transistors, and
- a second pair of resistors coupled to the third pair of transistors;
- and
- a second low-frequency recovery circuit comprising:
- a second common resistor,
- a fourth pair of transistors, wherein a first set of terminals is coupled to terminals of the second common resistor, and a second set of terminals of the fourth pair of transistors is coupled to the second pair of resistors, and
- a voltage offset digital-to-analog converter coupled to control terminals of the fourth pair of transistors.
Dependencies are inferred from the claim text.