BU64241GWZ Datasheet, PDF (15/24 Pages) Rohm – Linear Constant Current VCM Driver

BU64241GWZ
Datasheet
・Step B4 – Controlling ISRC Mode
ISRC mode is the control period in which the lens is already floating and the driver smoothly moves the lens based on
the proprietary behavior of the ISRC algorithm. ISRC operation keeps ringing at a minimum while achieving the fastest
possible settling time based on the ISRC operational conditions.
ISRC mode is used when M = 1 and the present DAC code is greater than the DAC code for point B. If the target DAC
code for point C is set so that the value is too large and will cause excess ringing, the point C DAC code is automatically
updated with a driver pre-determined value to minimize the ringing effect. When M = 1, the driver will automatically
switch between direct mode, step mode, and ISRC mode when the point A, B, and C DAC code conditions are met.
The condition for this automatic transitioning to occur is when the register values for point A, point B, point C, step time,
and step resolution are all set to values other than 0 and then the sequence will start when the EN bit is set equal to 1.
C
B
ISRC DAC codes*
A
Step mode
Direct mode
0
Start sequence
ISRC mode
* ISRC DAC codes
the details of ISRC
operation are
proprietary
Time (ms)
Figure 16. Three Modes Sequential Operation (Shown as DAC Codes)
0
Sequence start point
Time (ms)
Figure 17. Three Modes Sequential Operation (Shown as Lens Displacement)
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TSZ22111・15・001
15/20
TSZ02201-0H2H0B600460-1-2
01. Jul. 2013 Rev.004