Differential voltage-mode driver for microwave-assisted magnetic recording

A hard-disk drive system that facilitates a fast transition during microwave-assisted magnetic recording (MAMR) magnetic recording, the hard-disk drive system comprising:

• a write head including a microwave-assisted magnetic recording (MAMR) sensor;
• a voltage-mode (vMode) driver circuitry configured to drive a differential voltage of the MAMR sensor, the vMode driver circuitry including:
• a driver circuit configured to be responsive to feedback signals and has separate source and sink output terminals between which the MAMR sensor is coupled;
• a common-mode feedback (CMFB) loop coupled to the source and sink output terminals of the driver circuit, the CMFB loop configured to detect common-mode voltage (CMV) and provide feedback signals to the driver circuit to maintain CMV regulation of the MAMR sensor;
• and
• a differential voltage regulation loop coupled to the source and sink output terminals of the driver circuit, the differential voltage regulation loop configured to provide feedback signals to maintain a voltage differential of the MAMR sensor at a reference value.

A method that facilitates a fast transition during microwave-assisted magnetic recording (MAMR) magnetic recording, the method comprising:

• providing a reference value for a voltage differential;
• providing, by a driver circuit, a bias current to a MAMR sensor of a magnetic media read/write channel;
• maintaining, by a common-mode feedback (CMFB) loop coupled to the driver circuit, a common-mode voltage (CMV) regulation of the MAMR sensor;
• maintaining the voltage differential across the MAMR sensor at the reference value;
• and
• switching the voltage differential across the MAMR sensor with rise and fall times of twenty nanoseconds or less.