STCF07 Datasheet, PDF (21/26 Pages) STMicroelectronics – High power buck-boost white LED driver

STCF07
External component selection
11.5
R_LC selection
R_LC resistor value can be calculated with the following equations:
R_LC = (160 mV - I_LC * R_HC) / I_LC and P_RLC = R_LC * I_LC2
where P_RLC is the dissipated power on the R_LC resistor. It is recommended to use a thin
metal film resistor with a 1% or 5% tolerance.
11.6
NTC and R_X resistor selection
The NTC resistor for sensing LED temperature and the R_X resistor create a voltage divider.
The output of this divider is compared with the 1.192 V internal voltage reference. When
voltage on the output of the voltage divider is increased over the reference, the logic
switches off the power circuit. Voltage divider is possible to supply from the NTC pin, where
is output of the 1.8 V internal reference.
Doc ID 16757 Rev 3
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