CAT3612 Datasheet, PDF (9/13 Pages) Catalyst Semiconductor – Programmable 300mA Camera Flash LED Driver

BLOCK DIAGRAM
CAT3612
Figure 2. CAT3612 Functional Block Diagram
BASIC OPERATION
At power-up, the CAT3612 starts operating in 1x mode
where the output will be approximately equal to the
input supply voltage (less any internal voltage losses).
If the output voltage is sufficient to regulate all LEDs
currents the device remains in 1x operating mode.
If the input voltage is insufficient or falls to a level
where the regulated currents cannot be maintained,
the device automatically switches (after a fixed of
400µs) into 1.5x mode.
In 1.5x mode, the output is approximately equal to 1.5
times the input supply voltage (less any internal
voltage losses).
The above sequence is repeated each and every time
the chip is powered-up or is taken out of shutdown
mode (via EN/DIM pin).
© 2006 Catalyst Semiconductor, Inc.
9
Characteristics subject to change without notice
Doc. No. 5016 Rev. A