R1218N021A Datasheet, PDF (11/21 Pages) RICOH electronics devices division – Step-up DC/DC converter for White LED Backlight

R1218x
4) Efficiency vs. LED Current (6LED) L: LQH32CN220, Diode: CRS02 (Topt=25°C)
R1218x062A
R1218x062A
VIN=2.7V
VIN=3.6V
100
100
90
90
80
80
70
70
60
60
50
50
40
40
30
30
20
20
10
10
0
0
4
8
12 16 20
LED Current lLED (mA)
0
0
4
8
12 16 20
LED Current lLED (mA)
100
90
80
70
60
50
40
30
20
10
0
0
R1218x062A
VIN=4.2V
4
8
12 16 20
LED Current lLED (mA)
5) PWM Dimming Control (2 LED) VIN=3.6V, R1=10Ω
5-1. Duty vs. LED Current (Topt=25°C)
R1218x021A
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 (%)
11