AN1139 STMicroelectronics, AN1139 Datasheet - Page 54

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

AN1139 APPLICATION NOTE
Figure 37b. Mathcad Analisys of the Spindle Speed Control Loop
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Open Loop Gain
H( ) n
arg(
20 log(
.
H( ) n
Fref
Ifll
)
H( ) n
.
360
. 2
.
Zfilter( ) n Gm
)
100
110
120
130
140
150
160
170
180
90
50
40
30
20
10
10
20
30
40
50
0
0.01
0.01
.
.
Jm S( ) n
Km
.
.
0.1
0.1
. 2
1
OPEN LOOP MAGNITUDE RESPONSE in DB
OPEN LOOP PHASE RESPONSE in degree
let
1
1
K
f( ) n
f( ) n
Fref
Ifll
.
Gm
Jm
.
10
Km
. 2
10
.
Kc
K 20.933
=
100
100
1000
1000