STCF04 Datasheet, PDF (24/43 Pages) STMicroelectronics – Cell phones and smartphones

Description of the internal registers
STCF04
9.1.4
9.1.5
9.1.6
9.1.7
NTC_ON
This bit activates the comparators that monitor the LED temperature. NTC-related blocks
are always active regardless of this bit in Torch mode and Flash mode.
TCHV_H
Torch voltage HIGH: when set to 1, the SuperCap voltage is maintained to the value set by
the feature register (VDC_0~1) during Torch mode. If this bit is set to 0, voltage on the
SuperCap is regulated to maintain the desired torch current and optimize the efficiency in
Torch mode.
CHRG
This bit enables the charging of the SuperCap, when set to 1, the device starts to charge the
SuperCap by the limited current from the PVBAT. During this operation the active balancing
circuit is enabled.
MONTR
When this bit is set and the VDC voltage in the feature register is set to a non-zero value at
the same time, the device enters Monitoring mode.
9.2
Flash register (FL_REG) 01(hex)
Table 11. Flash register
CL_REG
(Write mode)
MSB
SUB ADD=01
FTIM_4
Power-ON, Shutdown
mode RESET value
0
FTIM_3
0
FTIM_2
0
FTIM_1
0
FTIM_0
0
FDIM_2
0
FDIM_1
0
LSB
FDIM_0
0
FDIM_0~2: these 3 bits define the LED current in Flash mode with 8 values.
FTIM_0~4: these 5 bits define the flash duration timer value in Flash mode with 32 values.
Table 12. Flash mode dimming registers settings (EXT_REG = 0)
F_DIM (hex)
0
1
2
3
4
5
6
7
DRIVE voltage
[mV]**
12
48
60
72
84
96
108
120
LED current [A]*
Example LED
current (A) for
R_FL = 10 mΩ
0.012 V / 0.048 V / 0.060 V / 0.072 V / 0.084 V / 0.096 V / 0.108 V / 0.120 V /
R_FL
R_FL
R_FL
R_FL
R_FL
R_FL
R_FL
R_FL
1.2
4.8
6
7.2
8.4
9.6
10.8
12
Note:
R_FL is the external sensing resistor, external MOS transistor connected, see Figure 3.
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