AN1139 STMicroelectronics, AN1139 Datasheet - Page 57

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

Figure 39a. Mathcad Analisys of the Voice Coil Current Loop
i
f( ) n
S( ) n
n
Kc
wz
wp
H1( ) n
H2( ) n
H3( ) n
, 1 1.01 6
Rc Cc1
(
Rc
1
Cc1 Cc2 Ri
10
2 i
.
1
.
. .
Kc
n
1
Lm S( ) n
..
Cc1 Cc2
Kamp
Cc1 Cc2
.
.
.
1
10
wamp
1
S( ) n
1
n
.
)
S( ) n
wota
.
1
Rm Rs
1
.
1
S( ) n
wz
S( ) n
wp
.
S( ) n
Kc
Fz
Fp
fl
=
5.051 10
. 2
wz
. 2
wp
Rm Rs
. 2 Lm
compensator
power stage
.
4
Fz 1.426 10
Fp
AN1139 APPLICATION NOTE
=
=
1.569 10
fl 1.438 10
=
3
4
3
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