MAX1570 Datasheet, PDF (5/11 Pages) Maxim Integrated Products – White LED Current Regulator with 1x/1.5x High-Efficiency Charge Pump

White LED Current Regulator with 1x/1.5x
High-Efficiency Charge Pump
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.)
LED CURRENT vs. SUPPLY VOLTAGE
20
18
16
EN1 = EN2 = V_IN
14
12
10 ^{EN1 = VIN, EN2 = GND}
8
6 ^{EN1 = GND, EN2 = V}IN
4
2
0
2.5 3.0 3.5 4.0 4.5 5.0 5.5
SUPPLY VOLTAGE (V)
LED CURRENT vs. TEMPERATURE
(V_IN = 3.3V, R_SET = 7.5kΩ)
12.0
11.9
11.8
11.7
11.6
11.5
11.4
11.3
11.2
11.1
11.0
-40
EN1 = IN
EN2 = GND
-15
10
35
60
85
TEMPERATURE (°C)
LED CURRENT vs. R_SET
30
25
20
15
10
EN1
=
EN1 ₌
IN, _EN2
EN2 _{= IN}
= _GND
5
EN1 _{= GND, EN2 = IN}
0
5.0
7.5
10.0
12.5
15.0
R_SET (kΩ)
TYPICAL OPERATING WAVEFORM
IN 1X MODE
MAX1570 toc13
TYPICAL OPERATING WAVEFORM
IN 1.5X MODE (I_LOAD = 90mA, V_IN = 3.6V)
MAX1570 toc14
I_IN
AC-COUPLED
10mA/div
I_IN
AC-COUPLED
10mA/div
V_IN
AC-COUPLED
1mV/div
V_IN
AC-COUPLED
20mV/div
V_OUT
AC-COUPLED
1mV/div
V_OUT
AC-COUPLED
5mV/div
STARTUP RESPONSE (V_IN = 3.3V)
(5 LEDs AT 15mA/LED)
MAX1570 toc15
I_IN
50mA/div
V_OUT
2V/div
2µs/div
400ns/div
DIMMING RESPONSE USING
PWM INTO EN1
MAX1570 toc16
I_LED
15mA TO 5mA
5mA/div
400µs/div
LINE-TRANSIENT RESPONSE
MAX1570 toc17
I_LED
15mA
5mA/div
V_OUT
AC-COUPLED
500mV/div
V_OUT
AC-COUPLED
500mV/div
100µs/div
EN1
0 TO 2V
2V/div
100µs/div
V_IN
4 TO 3.6V
500mV/div
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