HA13614FH Datasheet, PDF (18/26 Pages) Hitachi Semiconductor – Combo (Spindle & VCM) Driver

HA13614FH
C3 = 220 ⋅ 10^−12
[F]
(5)
C2 =
1
2
⋅
4⋅k+1− 8⋅k+1
k²
⋅ C3
[F]
(6)
R2 =
k
⋅
2
[Ω]
4 ⋅ k + 1 − 8 ⋅ k + 1 ^{2 ⋅ π ⋅ fc ⋅ C3}
(7)
R3 = R2
[Ω]
(8)
k = ^R5 = 0.604
R4
(9)
where, f c
: Cut off frequency of 3rd order LPF [Hz]
R1
: Output resistance of PWMDAC [Ω] (refer to Electrical Characteristics)
4. The driving current of VCM Ivcm is determined by following equation.
Ivcm
=
Vvcmin − VREF
R_S
⋅
Gvcm
[A]
(10)
where, Vvcmin : Input voltage on terminal VCMIN (pin 10) [V]
Gvcm : Transfer function of VCM driver [dB] (refer to Electrical Characteristics)
5. Capacitor C108 and resistor R104 are useful to dump the gain peaking of VCM driver. These
components also determine the gain band width of VCM driver BW1 which should be chosen less
than 10 kHz, as follows.
R104 = ^{12π ⋅ BW1 ⋅ Lvcm}
R_S
[kΩ]
(11)
C108 =
Lvcm
R_S + R_L
⋅
1
R104
[F]
(12)
where, R_L
: Coil resistance of VCM [Ω]
Lvcm : Coil inductance of VCM [H]
6. Retract current Iret is determined by following equation.
Iret =
0.7 ×
1+
R105
R106
− Vretsat
[A]
R_S + R_L
(13)
Vretsat : Output saturation voltage of retract driver [V]
(refer to Electrical Characteristics)
7. The relation between duty of input signal on terminal SPCNTL (pin 34) and output current of
spindle motor driver Ispn is as follows.
Ispn =
Vref − Voff1
Rnf
⋅ duty
[A]
(14)
Vref
Voff1
: Reference voltage of current control amplifier [V]
Vref = Vref2 (@SPNGAIN = 1)
Vref = Vref3 (@SPNGAIN = 0)
: Offset voltage of current control amplifier [V]
(refer to Electrical Characteristics)
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