Introduction

STCF03

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Introduction

The STCF03 is a buck-boost converter, dedicated to power and control the current of a

Power White LED in a camera cell phone. The device operates at a constant switching

frequency of 1.8 MHz typ. It provides an output voltage down to 2.5 V and up to 5.3 V, from

a 2.7 V to 5.5 V supply voltage. This supply range allows operation from a single cell

purposes. The current in Torch mode is adjustable from 15 mA to 200 mA. Flash mode

current is adjustable up to 800 mA, BGA version is able to deliver 600 mA at battery range

2.7 V to 3.3 V. The Aux LED current can be adjusted from 0 to 20 mA. The device uses an

external NTC resistor to sense the temperature of the white LED. These two last functions

may not be needed in all applications, and in these cases the relevant external components

can be omitted.

7.1

Buck-Boost converter

The regulation of the PWM controller is done by sensing the current of the LED through

forward voltage of the Flash LED, the device automatically can change the operation mode

between buck (step down) and boost (step up) mode.

7.2

Logic pin description

7.2.1

SCL, SDA pins

of these signals should be 3.0 V.

7.2.2

TRIG pin

This input pin is internally AND-ed with the TRIG_EN bit to generate the internal signal that

activates the flash operation. This gives to the user the possibility to accurately control the

internal pull-up nor pull-down is provided.

7.2.3

ATN pin

This output pin (open-drain, active LOW) is provided to better manage the information

configuration, the µP should regularly poll the STCF03 to verify if certain operations have

been completed, or to check diagnostic information. Alternatively, the µP can use the ATN

pin to be advised that new data are available in the STAT_REG, thus avoiding continuous

besides, automatically resets the ATN pin. The STAT_REG bits affecting the ATN pin status

are mapped in Table 16. No internal pull-up is provided.