AN2507 Datasheet, PDF (28/31 Pages) STMicroelectronics – This application note explains the design of a FLASH LED driver using the STCF03 device

Examples of register setup for each mode
AN2507
The data packet which has to be sent is in the table below.
Table 26. I²C data packet for activating the FLASH mode
Byte Hex
Binary
Comment
1 62 0 1 1 0 0 0 1 0
Device address + R/W bit
2 00 0 0 0 0 0 0 0 0
Command register address
3 DF 1 1 0 1 1 1 1 1 Data of the command register
4 0D 0 0 0 0 1 1 0 1 Data of the dimming register
The picture below shows the TRIG pin and the I²C bus timings.
Figure 21. Multiple flashes handled by the TRIG pin
200
100
ms
ms
1400 ms
I²C bus packet
TRIG_EN bit
TRIG pin
8.5
Example 5: A FLASH pulse longer than 1.5 s
Let's suppose that R_FL = 0.27 Ω and the targeted value of the FLASH current is 600 mA. The
task is to make a single FLASH pulse with a 4 seconds duration.
It is necessary to reload FTIM in the COMMAND REGISTER before the internal FLASH
timer reaches zero. This guarantees that the FLASH does go on and does not stop after
1.5 sec.
The first packet must contain also the DIMMING REGISTER data, if they are different from
those which were used in the previous operation.
● Packet 1
Sets FLASH mode with 1.5 s duration and the proper dimming.
Table 27. I²C data packet for activating the FLASH mode
Byte Hex
Binary
Comment
1 62 0 1 1 0 0 0 1 0
Device address + R/W bit
2 00 0 0 0 0 0 0 0 0
Command register address
3 DF 1 1 0 1 1 1 1 1 Data of the command register
4 0D 0 0 0 0 1 1 0 1 Data of the dimming register
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