AN1139 STMicroelectronics, AN1139 Datasheet - Page 19

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

Table 4. Spindle Rsense Voltage Limit
The current flowing into the coil will be calculated as follow:
•
Example with Rsense=0.3 and IL0/IL1=0 : Max Coil Current = (0.45 / 0.3) = 1.5 A.
4.3.2 Linear Current Control
The Linear mode of operation for the Spindle driver is activated by a ” 0” on bit 6 in the Spindle Control register
Reg #2.6.
Figure 6. Spindle Linear Current Control Loop
FLL
8.
“IL0”
V_sense_limit
------------------------------------ -
0
1
0
1
R sense
ERROR AMPLIFIER STAGE
OTA
+
-
Spindle Maximum Coil Current (Amp)
SPN_COMP
PIN#44
R c
C c
“IL1”
0
0
1
1
BUFFER
SEQUENCER
G=4
SENSE
OPAMP
POWER STAGE
G
CURRENT SENSE STAGE
A
V_SENSE_LIMIT (+/- 15%)
HIGH SIDE
LOW SIDE
ISENSE
PIN#5
AN1139 APPLICATION NOTE
VCC
B
.45V
.50V
.55V
.75V
Rsense
VCC
PINS#13,43
RSENSE
PINS#6,9
C
SPINDLE
MOTOR
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