STCF04TBR Datasheet, PDF (25/43 Pages) STMicroelectronics – High power white LED SuperCap™ driver with I²C interface

STCF04
Description of the internal registers
FTIM_0~4: these 5 bits define the maximum flash duration. It is intended to limit the energy
dissipated by the LED to a maximum safe value or to leave the control of the flash duration
to the STCF04 during normal operation. Values from 0~31 correspond to 0~410 ms
(according to Table 13). The timing accuracy is related to the internal oscillator frequency
that clocks the flash time counter (+/- 20%). Entering Flash mode (either by soft or hard
triggering) activates the flash time counter, which begins counting down from the value
loaded in the F_TIM register. When the counter reaches zero, Flash mode is stopped by
resetting the TRIG_EN bit, and simultaneously, the ATN pin is set to true (LOW) to alert the
microprocessor that the maximum time has been reached. The FTIM value remains
unaltered at the end of the count.
Table 13. Flash time dimming register settings
FTIM_DIM(hex) 0 1 2 3 4 5 6 7 8 9 A B C D E F
Flash length[ms] 0 5 10 15 20 25 30 35 40 45 50 55 60 65 70 90
FTIM_DIM(hex) 10 11 12 13 14 15 16 17 18 19 1A 1B 1C 1D 1E 1F
Flash length[ms] 110 130 150 170 190 210 230 250 270 290 310 330 350 370 390 410
9.3
AUX LED (AUX_REG) 02(hex)
Table 14. AUX LED register
AUX_REG
(Write mode)
MSB
SUB ADD = 02 AUXI_3 AUXI_2
Power-ON,
Shutdown mode
0
0
RESET value
AUXI_1
0
AUXI_0
0
LSB
AUXT_3 AUXT_2 AUXT_1 AUXT_0
0
0
0
0
AUXI_0~3: this 4-bit register defines the AUX LED current from 0 to 100 mA. See Table 15
AUX LED dimming for reference. Loading any value between 1 and 11 also starts the AUX
LED current source timer, if enabled. The AUX LED current source is active only in Idle
mode, and is deactivated in any other mode.
AUXT_0~3: this 4-bit register controls the timer that defines the ON-time of the AUX LED
current source. ON-time starts when the AUXI register is loaded with any value other than
zero, and stops after the time defined in the AUXT register. Values from 0 to 14 of the AUXT
register correspond to an ON-time of the AUX LED ranging from 100 to 1500 ms in 100 ms
steps. The value 15 puts the AUX LED into the continuous light mode. The
activation/deactivation of the AUX LED current source is controlled using only the AUXI
register.
Table 15. Auxiliary LED dimming table
AUXI (hex)
0
1
2
3
4
5
6
7
8
9
A
B
AUX LED current
[mA]
0
6
10 15 20 25 33 40 53 67 80 100
Doc ID 022927 Rev 3
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