Patent ID: 8462457

Claim:
A read head circuit, comprising: a read and write device configured to (i) magnetically write data on a platter, and (ii) read, via a read element, the data written magnetically on the platter, wherein the read element includes a first terminal and a second terminal; a normally-ON transistor including a first terminal connected to the first terminal of the read element, a second terminal connected to the second terminal of the read element, and a control terminal configured to receive a control voltage referenced from a power terminal, wherein the power terminal is configured to power the read and write device, wherein responsive to the control terminal being powered by the power terminal, the normally-ON transistor is configured to provide 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 by the power terminal, the normally-ON transistor is configured to short the first terminal of the read element to the second terminal of the read element; a first voltage limiting circuit configured to limit voltage input to (i) the first terminal of the normally-ON transistor and (ii) the first terminal of the read element; and a second voltage limiting circuit configured to limit voltage input to (i) the second terminal of the normally-ON transistor and (ii) the second terminal of the read element.