R1218N021A Datasheet, PDF (12/21 Pages) RICOH electronics devices division – Step-up DC/DC converter for White LED Backlight

R1218x
5-2. Output Voltage Waveform (Topt=25°C)
R1218x021A
fosc=200Hz
10
CE Input Voltage
5
0
10
Output Voltage
5
0
0
0.8 1.6 2.4 3.2
Time (ms)
R1218x021A
fosc=5kHz
10
CE Input Voltage
5
0
10
Output Voltage
5
0
0
0.04 0.08 0.12 0.16
Time (ms)
6) PWM Dimming Control (4 LED) VIN=3.6V, R1=10Ω
6-1. Duty vs. LED Current (Topt=25°C)
R1218x041A
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 (%)
6-2. Output Voltage Waveform (4 LED) (Topt=25°C)
R1218x041A
fosc=200Hz
10
CE Input Voltage
5
0
R1218x041A
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)
12