US Patent 7852584 Head IC, read circuit, and media storage device

A head IC adjusts an amplitude level of head read signals with regard to scattering in head output characteristics, so as to conform to the input dynamic range of the read channel AGC. An AGC amplifier is provided in a head IC connected to a read channel, and the feedback response speed of the AGC circuit of the head IC is set to be substantially slower than the feedback response speed of the AGC circuit of the read channel. Within the head IC, the amplitude of signals from the head is automatically adjusted, enabling adjustment of the input signal level to the input dynamic range of the AGC amplifier of the read channel. The AGC circuit of the head IC has no effect on the faster AGC operation of the AGC circuit of the read channel.