R1218N021A Datasheet, PDF (13/21 Pages) RICOH electronics devices division – Step-up DC/DC converter for White LED Backlight

R1218x
7) PWM Dimming Control (6 LED) VIN=3.6V, R1=10Ω
7-1. Duty vs. LED Current (Topt=25°C)
R1218x062A
25.0
22.5
20.0
17.5
15.0
12.5
10.0
7.5
5.0
2.5
0
0
5kHz
1kHz
200Hz
20 40 60 80 100
Duty (%)
7-2. Output Voltage Waveform (6 LED) (Topt=25°C)
R1218x062A
fosc=200Hz
10
CE Input Voltage
5
0
R1218x062A
fosc=5kHz
10
CE Input Voltage
5
0
20
Output Voltage
10
20
Output Voltage
10
0
0
0.8 1.6 2.4 3.2
Time (ms)
0
0
0.04 0.08 0.12 0.16
Time (ms)
8) VFB Voltage vs. Temperature
R1218x041A
0.215
VIN=3.6V
9) UVLO Detector Threshold/Released Voltage vs. Temperature
R1218x041A
1.74
VIN=3.6V
0.210
0.205
1.70
UVLO Released
1.66
0.200
1.62
0.195
1.58
UVLO Detector
0.190
1.54
0.185
-40 -25
0
25 50
Temperature Topt (°C)
75 85
1.50
-40 -25 0
25 50
Temperature Topt (°C)
75 85
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