Head amplifier
AssigneeSanyo Electric Co., Ltd.
InventorFukuji Anzai
Life of this patent
Estimating the term…
Abstract
A head amplifier is integrated into an IC with a minimum number of pins and outside parts as well. An offset cancellation circuit cancels offset voltages to prevent distortion of playback signals. An amplifier amplifies a playback signal to produce an output signal that is fed to one input of a differential amplifier. A reference voltage is fed to the second input of the differential amplifier. The input of the differential amplifier is compared in a comparator with the reference voltage to produce a feedback signal for cancelling offset voltages. The feedback path is frequency sensitive to reduce frequency response at low frequencies, and to compensate for distortions produced at high frequencies from using PNP transistors in the comparator.
Claims7
A head amplifier comprising:
- an amplifier effective for producing an output in response to a playback signal from a head;
- a differential amplifier;
- means for feeding said output to said differential amplifier;
- means for producing a reference voltage;
- means for connecting said reference voltage to said differential amplifier;
- means for comparing said output with said reference voltage;
- and
- means for feeding back an output of said means for comparing to an input of said amplifier.
A head amplifier comprising:
- an amplifier for amplifying a playback signal from a head to produce an output signal;
- a differential amplifier responsive to a difference between said output signal and a reference voltage to produce an amplified output signal;
- a feedback circuit;
- means in said feedback circuit for comparing said output signal with said reference voltage and feeding back a feedback signal to said amplifier;
- and
- means in said feedback circuit for amplifying said feedback signal with a high gain when a frequency of said output signal is lower than an effective frequency band and amplifying said feedback signal with a smaller gain than said high gain when the frequency of said output signal is higher than said effective frequency band.
Dependencies are inferred from the claim text.