Datasheet

MAX1570
White LED Current Regulator with 1x/1.5x
High-Efficiency Charge Pump
_______________________________________________________________________________________ 5
LED CURRENT vs. SUPPLY VOLTAGE
MAX1570 toc10
SUPPLY VOLTAGE (V)
LED CURRENT (mA)
5.04.54.03.53.0
2
4
6
8
10
12
14
16
18
20
0
2.5 5.5
EN1 = EN2 = V
IN
EN1 = GND, EN2 = V
IN
EN1 = V
IN
, EN2 = GND
LED CURRENT (mA)
603510-15
11.1
11.2
11.3
11.4
11.5
11.6
11.7
11.8
11.9
12.0
11.0
-40 85
LED CURRENT vs. TEMPERATURE
(V
IN
= 3.3V, R
SET
= 7.5kΩ)
MAX1570 toc11
TEMPERATURE (°C)
EN1 = IN
EN2 = GND
LED CURRENT vs. R
SET
MAX1570 toc12
R
SET
(kΩ)
LED CURRENT (mA)
12.510.07.5
5
10
15
20
25
30
0
5.0 15.0
E
N
1
=
I
N
,
E
N
2
=
G
N
D
E
N
1
=
E
N
2
=
I
N
E
N
1
=
G
N
D
,
E
N
2
=
I
N
Typical Operating Characteristics (continued)
(EN1 = EN2 = IN, C
IN
= 1µF, C1 = C2 = 1µF, C
OUT
= 4.7µF, R
SET
= 9.09kΩ, T
A
= +25°C, unless otherwise noted.)
TYPICAL OPERATING WAVEFORM
IN 1X MODE
MAX1570 toc13
2µs/div
V
IN
AC-COUPLED
1mV/div
I
IN
AC-COUPLED
10mA/div
V
OUT
AC-COUPLED
1mV/div
TYPICAL OPERATING WAVEFORM
IN 1.5X MODE (I
LOAD
= 90mA, V
IN
= 3.6V)
MAX1570 toc14
400ns/div
V
IN
AC-COUPLED
20mV/div
I
IN
AC-COUPLED
10mA/div
V
OUT
AC-COUPLED
5mV/div
STARTUP RESPONSE (V
IN
= 3.3V)
(5 LEDs AT 15mA/LED)
MAX1570 toc15
400µs/div
I
IN
50mA/div
V
OUT
2V/div
DIMMING RESPONSE USING
PWM INTO EN1
MAX1570 toc16
100µs/div
I
LED
15mA TO 5mA
5mA/div
V
OUT
AC-COUPLED
500mV/div
EN1
0 TO 2V
2V/div
LINE-TRANSIENT RESPONSE
MAX1570 toc17
100µs/div
I
LED
15mA
5mA/div
V
OUT
AC-COUPLED
500mV/div
V
IN
4 TO 3.6V
500mV/div