S1F81210Y0A Epson Electronics America, Inc., S1F81210Y0A Datasheet - Page 8

• Manufacturer Part Number: S1F81210Y0A
• Description: Step-up Dc-dc Converter
• Manufacturer: Epson Electronics America, Inc.

9. OPERATION DESCRIPTION
9. OPERATION DESCRIPTION
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● Adjustment Method of LED current
● Soft-start
● Brightness Adjustment Using CE pin
and VSS pin. The feedback reference is controlled at 0.5V. The LED current is shown below.
The S1F81210 has soft start function while approximately 500μsec after starting operation.
The maximum duty is limited to 50% during soft start, although it’s 75% at normal operation.
The LED current is controlled by resistor (R1 in “TYPICAL APPLICATIONS”) connected between FB pin
The S1F81210 can be light white LEDs of 2 to 6 in series by boosting up the input voltage using a switching
regulator method. The LED current is controlled by resistor connected between FB pin and VSS pin. The
range of switching duty is 0 to 75%. In case of light load (approximately 1mA), the duty is 0% and S1F81210
tends to skip pulses.
The S1F81210 is able to adjust the mean current of LED by the clock signal duty input to CE pin.
The recommended frequency range is 100 to 400Hz and the duty is 10 to 90%, when the clock signal is
input to CE pin.
I
LED
=0.5/R1
CE input signal
EPSON
(Duty: 10 to 90%)
100 to 400Hz
S1F81210Y0A (Rev.1.0)