cat4237 Catalyst Semiconductor, cat4237 Datasheet - Page 6

• Manufacturer Part Number: cat4237
• Description: High Voltage Cmos Boost White Led Driver
• Manufacturer: Catalyst Semiconductor

CAT4237
TYPICAL CHARACTERISTICS
V
Doc. No. MD-5013, Rev. B
IN
= 3.6V, C
90
85
80
75
70
65
90
85
80
75
70
65
35
30
25
20
15
10
LED Current vs. Input Voltage (8 LEDS)
5
0
2.5
5
5
8 LED Efficiency vs. Load Current
7 LED Efficiency vs. Load Current
IN
7 LEDs
VOUT ~ 23V at 20mA
L = 33uH
= 4.7μF, C
8 LEDs
VOUT ~ 27V at 20mA
L = 33uH
R
FB
10
3.0
10
LED CURRENT [mA]
LED CURRENT [mA]
= 20 Ω
INPUT VOLTAGE [V]
R
FB
15
3.5
15
OUT
= 15 Ω
VIN = 3.6V
VIN = 4.2V
VIN = 4.2V
VIN = 3.6V
= 0.22µF, L = 33µH with 8 LEDs at 20mA, T
20
4.0
20
R
FB
= 10 Ω
25
25
4.5
30
30
5.0
6
-0.5%
-1.0%
1.0%
0.5%
0.0%
90
85
80
75
70
65
90
85
80
75
70
65
3.0
3.0
8 LED Efficiency vs. Input Voltage
6 LED Efficiency vs. Load Current
5
LED Current Regulation (20mA)
6 LEDs
VOUT ~ 20V at 20mA
L = 33uH
8 LEDs
VOUT ~ 27V at 20mA
L = 33uH
AMB
3.3
10
INPUT VOLTAGE [V]
3.5
= 25ºC, unless otherwise specified.
LED CURRENT [mA]
INPUT VOLTAGE [V]
3.6
15
Characteristics subject to change without notice
4.0
3.9
15mA
20mA
20
VIN = 4.2V
VIN = 3.6V
4.2
4.5
© Catalyst Semiconductor, Inc.
25
4.5
5.0
30
4.8