Electrostatic discharge protection circuit for magneto-resistive read elements

A read head circuit, comprising:

• a read element configured to read data stored magnetically on a platter, the read element including a first terminal and a second terminal;
• a normally-ON transistor including
• a first terminal directly connected to the first terminal of the read element,
• a second terminal directly connected to the second terminal of the read element, and
• a control terminal,
• wherein
• responsive to the control terminal being powered, the normally-ON transistor provides an open circuit between the first terminal of the read element and the second terminal of the read element, and
• responsive to the control terminal not being powered, the normally-ON transistor is configured to short the first terminal of the read element to the second terminal of the read element;
• and
• a first voltage limiting circuit configured to limit voltage input to the first terminal of the normally-ON transistor and the first terminal of the read element,
• wherein
• the first voltage limiting circuit includes a first diode and a second diode,
• an anode of the first diode and a cathode of the second diode are respectively in communication with the first terminal of the read element and the first terminal of the normally-ON transistor, and
• a cathode of the first diode is in communication with an anode of the second diode.