| 摘要 |
<p>The preamplifier for use with a magneto-resistive element, includes two MR terminals for coupling the preamplifier to two terminals of the MR element, and two differential output terminals. A controlled current source has a current output coupled to the first MR terminal, and a control input governing a magnitude of current output. A first output device supplies a signal indicating the magnitude of the output current, and the first output signal is applied to the first preamplifier output terminal. A controlled current sink has a current input coupled to the second MR terminal, and a control input governing the magnitude of the consumed current. A second output device produces a second output signal to the second preamplifier output terminal, such signal indicating a magnitude of current though the conduction path. A first feedback loop produces a first error control signal based on differential DC and LF components of the output signal, for coupling to the control input of the current source. A second feedback loop produces a second error control signal based on common mode DC and LF components of the output signal and a reference voltage signal for coupling to the current sink.</p> |
