MD215 SITI [Silicon Touch Technology Inc.], MD215 Datasheet - Page 7

• Manufacturer Part Number: MD215
• Description: VCM Driver for Mobile Phone
• Manufacturer: SITI [Silicon Touch Technology Inc.]

SP-MD215-A.001
-3dB frequency
is shown as follows,
The following example explains how to design the low pass filter. For PWM
frequency
80mA and V
According to equation (1) & (2), we have
By choosing
Owing to
Then
In order to ensure the stabilization of output current, the compensation
capacitance C
of C
the sense of frequency response compensation to confirm stability while VCM
operating.
點晶科技股份有限公司
SILICON TOUCH TECHNOLOGY INC.
L
is about 0.1~1uF and maybe fine tune depending on the different VCM. It is
I
MAX
f
PWM
PWM
C
=
IN
L
=
V
is suggested placing in parallel with VCM. The suggestion value
=
ω
= 2.8V. Please determine C
IN MAX
92.8
15
f
0.1
3 dB
,
3
dB
uF
is suggested lower than the 1/1000 of the PWM frequency. It
kHz
=
2
, we can get
( )
π
A
, and desired maximum output constant current,
ω
Version
(
3
R
R
dB
=
A
A
15
=
//
=
1
1000
R C
(
40
R
B
1
：
R
)
A
k
A.001
B
Ω ,
+
(
ω
IN
R
R
PWM
A
B
=
//
R
)
1000
V
B
R
DD
1
=
B
IN
)
30
( )
=
, R
A
f
k
17.1
PWM
Ω
A
,
and R
k
=
Ω .
92.8
B
Hz
.
Page
I
：
MAX
6
, is
(2)