Table of Contents
Advertisement
FROM
READ!
WRITE
INTERFACE
CIRCUIT
FROM
STATUS
CIRCUIT
FROM
SEEK AND
INTERFACE
MODULE
FROM
READ!
WRITE
INTERFACE
CIRCUIT
FROM
SELECT
CIRCUIT
+WRITE L
-WRITE L
WRITE
CURRENT
SWITCH
+12 VDC
+12 VDC
DCOK L
+12 VDC
ERASE GATE L
WRITE
CURRENT
1-----tDIFFERENTIAL
GENERATOR
WRITE
VOLTAGE
REFERENCE
+12 V
GATE
ERASE
CURRENT
GENERATOR
SWITCH
+12 VDC
ERASE
HEAD SEL A
WRITE GATE L
MULTIPLEXER
HEAD SEL B
SEL A L
~
1
~
4
r-HEADs-l
~
I
I
L-f-+-+-M"'H 5
.-----'-:...,~
:
~
1
~
4
-
3
' - - -
1---+:
...J.I'YYY'..-
1
I
I
.----+I...,~
I
I
I
I
L ______
.J
MR-l0036
Figure 6-23
Write Circuit Detail
6.3.9.1
Write Current Generator Detail - The write current generator provides a selectable current for
the differential write switch. These currents are derived from the + 12 V from the + 12 V gate.
When the WRITE CURRENT SWITCH signal is asserted, a low current for the inner tracks (44 through
79) is provided to the differential write switch. When the WRITE CURRENT SWITCH signal is
unasserted, a high current for the outer tracks (0 through 43) is provided to the differential write switch.
6.3.9.2
Voltage Reference Detail - The voltage reference provides a stable voltage to the differential
write switch. This reference voltage makes sure that the outputs of the differential write switch are
balanced.
6.3.9.3
+12 V Gate Detail- The +12 V gate receives the RjW modules supply voltage (+12 Vdc) and a
DCOK signal. If DCOK remains asserted, the gate passes +12 Vdc to the module's circuits. This makes
sure that the write circuits are disabled if a low power condition exists.
6.3.9.4
Differential Write Switch Detail- The differential write switch converts the write data from the
RjW interface circuits to write currents for the RjW heads. Figure 6-24 shows the conversion of WRITE
DA T A from the controller (Paragraph 6.3.8.1) to write currents for the heads. For this conversion, the
differential write switch requires a write current and a reference voltage.
6-26
Advertisement
Chapters
Table of Contents
