Fujitsu MHY2120BH, MHY2160BH Read/write Circuit, Read/write preamplifier PreAMP, Write circuit

Theory of Device Operation

4.6 Read/write Circuit

The read/write circuit consists of the read/write preamplifier (PreAMP), the write circuit, the read circuit, and the time base generator in the read channel (RDC) block which is integrated into LSI. Figure 4.4 is a block diagram of the read/write circuit.

4.6.1 Read/write preamplifier (PreAMP)

PreAMP equips a read preamplifier and a write current switch, that sets the bias current to the MR device and the current in writing. Each channel is connected to each data head, and PreAMP switches channel by serial I/O. In the event of any abnormalities, including a head short-circuit or head open circuit, the write unsafe signal is generated so that abnormal write does not occur.

4.6.2 Write circuit

The write data is transferred from the hard disk controller (HDC) to the RDC in LSI. The write data is sent to the PreAMP as differential signal from LSI, and the data is written onto the media.

(1) Write precompensation

Write precompensation compensates, during a write process, for write non- linearity generated at reading.

Figure 4.4 Read/write circuit block diagram

4-10 C141-E262