Differential sense of embedded contact sensor (ecs) and near-field temperature sensor (nts) utilizing chopping amplifier

A method for differential sensing of bias voltages across resistive temperature detectors (RTDs) in a data storage device, comprising:

• generating a first bias voltage across a first RTD coupled between a first voltage source and a second voltage source and a second bias voltage across a second RTD coupled between the first and second voltage sources;
• reducing offset between the first bias voltage and the second bias voltage;
• and
• modulating a differential bias voltage between the first RTD and the second RTD and amplifying the modulated differential bias voltage.

A circuit for differential sensing of bias voltages across resistive temperature detectors (RTDs) in a data storage device, comprising:

• a first RTD and a second RTD coupled to a first voltage source;
• a tuning bridge coupled between the first and second RTDs and a second voltage source, the tuning bridge being configured to reduce offset between a first bias voltage across the first RTD and a second bias voltage across the second RTD;
• and
• a low noise amplifier (LNA) configured to receive the first bias voltage and the second bias voltage as a differential bias voltage.

A data storage device comprising:

• a first resistive temperature detector (RTD) coupled between a first voltage source and a second voltage source;
• a second RTD coupled between the first voltage source and the second voltage source;
• a low noise amplifier (LNA) configured to receive a first bias voltage across the first RTD and a second bias voltage across the second RTD as a differential bias voltage;
• and
• a modulator coupled between the first and second RTDs and the LNA to modulate the differential bias voltage.