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Fujitsu MJA2500BH Maintenance Manual - Page 59

Air filter, 4.3 Circuit Configuration, Air filter

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4.3 Circuit Configuration 4.2.4 Air filter There are two types of air filters: a breather filter and a circulation filter. The breather filter makes an air in and out of the DE to prevent unnecessary pressure around the spindle when the disk starts or stops rotating. When disk drives are transported under conditions where the air pressure changes a lot, filtered air is circulated in the DE. The circulation filter cleans out dust and dirt from inside the DE. The disk drive cycles air continuously through the circulation filter through an enclosed loop air cycle system operated by a blower on the rotating disk. 4.3 Circuit Configuration Figure 4.1 shows the power supply configuration of the disk drive, and Figure 4.2 shows the disk drive circuit configuration. (1) Read/write circuit The read/write circuit consists of two circuits; read/write preamplifier (PreAMP) and read channel (RDC) which is integrated into LSI with MCU and HDC. The PreAMP consists of the write current switch circuit, that flows the write current to the head coil, and the voltage amplifier circuit, that amplitudes the read output from the head. The RDC is the read demodulation circuit using the MEEPRML (Modified Extended Extended Partial Response Maximum Likelihood), and contains the Viterbi detector, programmable filter, adaptable transversal filter, times base generator, data separator circuits, RLL (Run Length Limited) encoder and servo demodulation circuit. (2) Servo circuit The position and speed of the voice coil motor are controlled by closed-loop servo using the servo information recorded on the data surface. The servo information is an analog signal converted to digital for processing by a MPU and then reconverted to an analog signal for control of the voice coil motor. The MPU precisely sets each head on the track according on the servo information on the media surface. (3) Spindle motor driver circuit The circuit measures the interval of a PHASE signal generated by counterelectromotive voltage of a motor and controls the motor speed comparing target speed. C141-E293 4-3

Section	Page
Front Cover	1
FOR SAFE OPERATION	2
Revision History	3
Preface	5
Important Alert Items	9
Manual Organization	11
Contents	13
Illustrations	19
Figures	19
Tables	21
CHAPTER 1 Device Overview	23
1.1 Features	24
1.1.1 Functions and performance	24
1.1.2 Adaptability	24
1.1.3 Interface	25
1.2 Device Specifications	27
1.2.1 Specifications summary	27
1.2.2 Model and product number	28
1.3 Power Requirements	29
1.4 Environmental Specifications	32
1.5 Acoustic Noise	33
1.6 Shock and Vibration	33
1.7 Reliability	34
1.8 Error Rate	35
1.9 Media Defects	35
1.10 Load/Unload Function	35
1.10.1 Recommended power-off sequence	36
1.11 Advanced Power Management (APM)	36
1.12 Interface Power Management (IPM)	38
1.12.1 Host-initiated interface power management (HIPM)	38
1.12.2 Device-initiated interface power management (DIPM)	38
CHAPTER 2 Device Configuration	41
2.1 Device Configuration	42
2.2 System Configuration	43
2.2.1 SATA interface	43
2.2.2 Drive connection	43
CHAPTER 3 Installation Conditions	45
3.1 Dimensions	46
3.2 Mounting	47
3.3 Connections with Host System	53
3.3.1 Device connector	53
3.3.2 Signal segment and power supply segment	54
3.3.3 Connector specifications for host system	54
3.3.4 SATA interface cable connection	55
3.3.5 Note about SATA interface cable connection	55
CHAPTER 4 Theory of Device Operation	57
4.1 Outline	58
4.2 Subassemblies	58
4.2.1 Disk	58
4.2.2 Spindle	58
4.2.3 Actuator	58
4.2.4 Air filter	59
4.3 Circuit Configuration	59
4.4 Power-on Sequence	62
4.5 Self-calibration	64
4.5.1 Self-calibration contents	64
4.5.2 Execution timing of self-calibration	65
4.5.3 Command processing during self-calibration	65
4.6 Read/write Circuit	66
4.6.1 Read/write preamplifier (PreAMP)	66
4.6.2 Write circuit	66
4.6.3 Read circuit	67
4.6.4 Digital PLL circuit	67
4.7 Servo Control	68
4.7.1 Servo control circuit	68
4.7.2 Data-surface servo format	70
4.7.3 Servo frame format	72
4.7.4 Actuator motor control	73
4.7.5 Spindle motor control	74
CHAPTER 5 Interface	75
5.1 Physical Interface	76
5.1.1 Interface signals	76
5.1.2 Signal interface regulation	78
5.1.3 Electrical specifications	80
5.1.4 Connector pinouts	81
5.1.5 P11 function	82
5.1.6 Hot Plug	84
5.2 Logical Interface	85
5.2.1 Communication layers	86
5.2.2 Outline of the Shadow Block Register	87
5.2.3 Outline of the frame information structure (FIS)	88
5.2.4 Shadow block registers	96
5.3 Host Commands	101
5.3.1 Command code and parameters	101
5.3.2 Command descriptions	104
5.3.3 Error posting	247
5.4 Command Protocol	249
5.4.1 Non-data command protocol	250
5.4.2 PIO data-in command protocol	252
5.4.3 PIO data-out command protocol	254
5.4.4 DMA data-in command protocol	256
5.4.5 DMA data-out command protocol	257
5.4.6 Native Command Queuing protocol	258
5.5 Power-on and COMRESET	261
CHAPTER 6 Operations	263
6.1 Reset and Diagnosis	264
6.1.1 Response to power-on	264
6.1.2 Response to COMRESET	266
6.1.3 Response to a software reset	269
6.2 Power Save	270
6.2.1 Power save mode	270
6.2.2 Power commands	272
6.3 Power Save Controlled by Interface Power Management (IPM)	273
6.3.1 Power save mode of the interface	273
6.4 Read-ahead Cache	275
6.4.1 Data buffer structure	275
6.4.2 Caching operation	276
6.4.3 Using the read segment buffer	278
6.5 Write Cache	282
6.5.1 Cache operation	282
CHAPTER 7 Maintenance and Diagnosis	285
7.1 Maintenance	286
7.1.1 Rules for maintenance	286
7.1.2 Maintenance requirements	287
7.1.3 Maintenance levels	289
7.1.4 Disk drive revision number	290
7.1.5 Tools and test equipment	292
7.1.6 Self-diagnostics	292
7.1.7 Test	292
7.2 Operation Confirmation	295
7.2.1 Operation test	295
7.2.2 Diagnostic test	295
7.3 Troubleshooting Procedure	296
7.3.1 Troubleshooting procedure	296
7.3.2 Troubleshooting disk drive replaced in field	296
7.3.3 Troubleshooting at factory	298
7.4 Disk Drive Removal Procedure	299
7.5 Spare Disk Drive	299
Glossary	301
Acronyms and Abbreviations	305
Index	307
Comment Form	315

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4.3

Circuit Configuration

4.2.4

Air filter

There are two types of air filters:

a breather filter and a circulation filter.

The breather filter makes an air in and out of the DE to prevent unnecessary

pressure around the spindle when the disk starts or stops rotating.

When disk

drives are transported under conditions where the air pressure changes a lot,

filtered air is circulated in the DE.

The circulation filter cleans out dust and dirt from inside the DE.

The disk drive

cycles air continuously through the circulation filter through an enclosed loop air

cycle system operated by a blower on the rotating disk.

4.3

Circuit Configuration

Figure 4.1 shows the power supply configuration of the disk drive, and Figure 4.2

shows the disk drive circuit configuration.

(1) Read/write circuit

The read/write circuit consists of two circuits; read/write preamplifier (PreAMP)

and read channel (RDC) which is integrated into LSI with MCU and HDC.

The PreAMP consists of the write current switch circuit, that flows the write

current to the head coil, and the voltage amplifier circuit, that amplitudes the read

output from the head.

The RDC is the read demodulation circuit using the MEEPRML (Modified

Extended Extended Partial Response Maximum Likelihood), and contains the

Viterbi detector, programmable filter, adaptable transversal filter, times base

generator, data separator circuits, RLL (Run Length Limited) encoder and servo

demodulation circuit.

(2) Servo circuit

The position and speed of the voice coil motor are controlled by closed-loop servo

using the servo information recorded on the data surface.

The servo information is

an analog signal converted to digital for processing by a MPU and then

reconverted to an analog signal for control of the voice coil motor.

The MPU precisely sets each head on the track according on the servo information

on the media surface.

(3) Spindle motor driver circuit

The circuit measures the interval of a PHASE signal generated by counter-

electromotive voltage of a motor and controls the motor speed comparing target

speed.

C141-E293

4-3