Stmicroelectronics S.r.l.

Stmicroelectronics Gmbh

Stmicroelectronics International N.v.

Enrico Mammei

Paolo Pulici

Michele Bartolini

Enrico Sentieri

Edoardo Contini

Matteo Tonelli

Marco Mazzini

Dennis Hogg

Marco Ciuffolini

Dennis W Hogg

Piero Malcovati

Dario Livornesi

Edoardo Marino

Edoardo Bonizzoni

Alessio Facen

Francesco Piscitelli

Alessio Emanuele Vergani

Mojtaba Mohammadi Abdevand

Nicola Lupo

Stefano Colli

Paolo Sanna

Francesco Ravelli

Alessio Vallese

In accordance with an embodiment, a circuit is configured to vary an intensity of a drive current of a resistive heater element based on the digital control signal. The circuit includes and output circuit configured to control a respective slew rate and an electric energy dissipated in the resistive heater element independently of a resistance value of the resistive heater element.

Circuit for controlling a resistive circuit

A system for determining a fly height includes a first head of a disk drive, a second head of the disk drive, a capacitive sensor circuit coupled to the first head and the second head, and a logic device coupled to the capacitive sensor circuit. The capacitive sensor circuit is configured to measure a first capacitance between the first head and the first disk, remove noise from the first capacitance using a second capacitance between the second head and the second disk, and based thereon determine a corrected first capacitance. The logic device is configured to determine the fly height between the first head and the first disk using the corrected first capacitance.

System and method for disk drive fly height measurement

A method for determining a fly height includes measuring a first differential voltage between a first head of a disk drive and a reference voltage with a first front end circuit, converting the first differential voltage to a first analog current signal with the first front end circuit, and converting the first analog current signal to a second differential voltage with a first back end circuit. The first front end circuit is coupled with the first head. The first back end circuit is coupled with the first front end circuit. The method further includes determining a first capacitance between the first head and a first disk of the disk drive based on the second differential voltage and determining the fly height between the first head and the first disk using the first capacitance.

According to an embodiment, a circuit includes a biasing and a low-frequency recovery circuit. The biasing circuit includes a voltage digital to analog converter (V-DAC), a differential difference amplifier coupled to the V-DAC, a common-mode feedback (CMFB) amplifier coupled to the differential difference amplifier, and a first pair of transistors arranged as a high-impedance structure and coupled to the differential difference amplifier and the CMFB amplifier. The low-frequency recovery circuit includes a current digital to analog converter (C-DAC), a second pair of transistors arranged as a high-impedance structure and coupled to the first pair of transistors, a pair of resistors having a resistance value equal to half a resistance of the resistive sensor, the pair of resistors arranged between the second pair of transistors and coupled to the C-DAC, and a gain circuit coupled to shared nodes between the second pair of transistors and the pair of resistors.

Circuit for biasing an external resistive sensor

A method to drive a digital to analog converter (DAC), the method including setting a reference current for the DAC with a reference current source, a base voltage being responsive to changes in a reference voltage at a reference node coupled with the reference current source; sensing a change in the reference voltage; and adaptively steadying the base voltage based on the change in the reference voltage to maintain proportionality between an output current of the DAC and the reference current.

Methods and devices for adaptive voltage steadying

In an embodiment, an electronic circuit includes: an input differential pair including first and second transistors; a first pair of transistors in emitter-follower configuration including third and fourth transistors, and an output differential pair including fifth and sixth transistors. The third transistor has a control terminal coupled to the first transistor, and a current path coupled to a first output terminal. The fourth transistor has a control terminal coupled to the second transistor, and a current path coupled to a second output terminal. The fifth transistor has a control terminal coupled to the first transistor, and a first current path terminal coupled to the first output terminal. The sixth transistor has a control terminal coupled to the second transistor, and a first current path terminal coupled to the second output terminal. First and second termination resistors are coupled between the first pair of transistors and the output differential pair.

Differential driver

In an embodiment, a linear voltage regulator includes: an output transistor having a first current path terminal configured to be coupled to a load, and a second current path terminal coupled to a first supply terminal, where the output transistor is configured to provide, at the first current path terminal, a regulated output voltage; a voltage source circuit configured to provide, in an open loop manner, a first voltage to a control terminal of the output transistor; and a feedback loop coupled between the first current path terminal of the output transistor and the control terminal of the output transistor, the feedback loop including a sense transistor having a first current path terminal coupled to the first current path terminal of the output transistor.

Voltage regulator

A method to determine a relative delay between a current-overshoot signal and a write data signal for a hard disk drive preamplifier, the method including using a memory element to strobe a test current-overshoot signal with a test data signal; counting a number of strobed transitions of the test current-overshoot signal; adjusting the delay based on the number of strobed transitions; setting a phase difference between the current-overshoot signal and the write data signal according to the delay; and using the memory element to strobe the current-overshoot signal with the write data signal.

Automatic skew calibration circuit for pattern-dependent dynamic wave shaping for HDD preamplifier write

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Vittuone, Italy

Enrico Mammei