AN1139 STMicroelectronics, AN1139 Datasheet - Page 37

• Manufacturer Part Number: AN1139
• Description: L6254 - L6268 - L6269 12V DISK DRIVE POWER COMBO IC
• Manufacturer: STMicroelectronics

Figure 19. External Bemf Processing Configuration
The Figure #20, shows the External Speed control configuration. The Feedback frequency is taken from the
disk itself and the control voltage is entered on FLL_FILTER pin (#21). An explanation of this configuration setup
can be found in chapter 4 (Spindle Circuits), section 4.12 (External Speed Control option).
Figure 20. External Speed Control Configuration
The Figure #21, shows both the External BEMF processing and the Speed control together in the same con-
figurations. This option is the combination of the two features and it is illustrated in the explanation of the previ-
ous Figures #19 and Figure #20.
Microprocessor
PROCESSING
Microprocessor
CONTROL LOOP
o r D S P
BEMF
or DSP
SPEED
FLL_FILTER PIN
INDEX PIN
SYSCLK
SDATA
SDEN
FCOM
SCLK
S Y S C L K
POR
SDATA
S D E N
F C O M
S C L K
P O R
BEMF PROCESSING
SPEED CONTROL
P O W E R C O M B O
POWER COMBO
LOOP
AN1139 APPLICATION NOTE
V O I C E C O I L
S P I N D L E
M O T O R
M O T O R
VOICE COIL
SPINDLE
MOTOR
MOTOR
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