DRV201_15 Datasheet, PDF (19/29 Pages) Texas Instruments – DRV201 Voice Coil Motor Driver for Camera Auto Focus

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8 Application and Implementation
DRV201
SLVSB25C – AUGUST 2011 – REVISED JUNE 2015
NOTE
Information in the following applications sections is not part of the TI component
specification, and TI does not warrant its accuracy or completeness. TI’s customers are
responsible for determining suitability of components for their purposes. Customers should
validate and test their design implementation to confirm system functionality.
8.1 Application Information
The DRV201 device is a voice coil motor driver designed for camera auto focus control. The device allows for a
highly efficient PWM current control for VCM, while reducing lens ringing in order to significantly lower the time
needed for the lens to auto focus. The following design is a common application of the DRV201 device.
8.1.1 VCM Mechanical Ringing Frequency
Ringing compensation is dependent on the VCM resonance frequency, and this can be controlled through the
VCM_FREQ register (07h) from 50 Hz up to 150 Hz. VCM mechanical ringing frequency for the ringing
compensation can be selected using Equation 3. The formula gives the VCM_FREQ[7:0] register value in
decimal which should be rounded to the nearest integer.
VCM _ FREQ = 383 - ¹⁹²⁰⁰
F_res
(3)
Default VCM mechanical ringing frequency is 76.4 Hz.
VCM _ FREQ = 383 - ¹⁹²⁰⁰ = 131.69 Þ 132 Þ '1000 0011'
76.4
(4)
8.2 Typical Application
V_in
1µF
DRV201
VBAT ISOURCE
SCL
To/From a
controller
SDA
ISINK
GND
+
VCM
±
Figure 20. Typical Application Schematic
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