MAX1570 Datasheet, PDF (4/11 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
(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 EFFICIENCY vs. SUPPLY VOLTAGE
(4 LEDs)
100
95
10mA/LED, EN1 = V_IN, EN2 = GND
90
85
80
75
70
65
60
55 ^{5mA/LED, EN1 = GND,}
EN2 = V_IN
50
3.0 3.2 3.4 3.6
15mA/LED,
EN1 = EN2 = V_IN
3.8 4.0 4.2
SUPPLY VOLTAGE (V)
SUPPLY POWER vs. SUPPLY VOLTAGE
(4 LEDs)
400
15mA/LED,
350
EN1 = EN2 = V_IN
300
250
200
150
10mA/LED, EN1 = V_IN,
EN2 = GND
100
50
0
2.5
5mA/LED, EN1 = GND,
EN2 = V_IN
3.0 3.5 4.0 4.5 5.0 5.5
SUPPLY VOLTAGE (V)
SUPPLY CURRENT vs. SUPPLY VOLTAGE
(4 LEDs)
100
90
80
15mA/LED,
EN1 = EN2 = V_IN
70
60
10mA/LED, EN1 = V_IN,
50
EN2 = GND
40
5mA/LED, EN1 = GND,
30
EN2 = V_IN
20
10
0
2.5 3.0 3.5 4.0 4.5 5.0
SUPPLY VOLTAGE (V)
LED EFFICIENCY vs. SUPPLY VOLTAGE
(5 LEDs)
100
95
10mA/LED, EN1 = V_IN, EN2 = GND
90
85
80
75
70
65
60
55 ^{5mA/LED, EN1 = GND,}
EN2 = V_IN
50
3.0 3.2 3.4 3.6
15mA/LED,
EN1 = EN2 = V_IN
3.8 4.0 4.2
SUPPLY VOLTAGE (V)
SUPPLY POWER vs. SUPPLY VOLTAGE
(5 LEDs)
500
450
15mA/LED,
400
EN1 = EN2 = V_IN
350
300
250
200
150
100
50
0
2.5
10mA/LED, EN1 = V_IN,
EN2 = GND
5mA/LED, EN1 = GND,
EN2 = V_IN
3.0 3.5 4.0 4.5 5.0
SUPPLY VOLTAGE (V)
SUPPLY CURRENT vs. SUPPLY VOLTAGE
(5 LEDs)
120
100
15mA/LED,
EN1 = EN2 = V_IN
80
10mA/LED, EN1 = V_IN,
60
EN2 = GND
40
5mA/LED, EN1 = GND,
EN2 = V_IN
20
0
2.5 3.0 3.5 4.0 4.5 5.0
SUPPLY VOLTAGE (V)
100
95
90
85
80
75
70
65
60
55
50
5
EFFICIENCY vs. LED CURRENT
(4 LEDs, EN1 = PWM AT 1kHz)
V_IN = 3.9V
V_IN = 3V
6 7 8 9 10 11 12 13 14 15
LED CURRENT (mA)
LED CURRENT vs. PWM DIMMING
DUTY CYCLE INTO EN1 (5 LEDs)
20
18 _{fPWM = 1kHz}
16 ^{VIN = 3.3V}
14
12
10
8
6
4
2
0
0 10 20 30 40 50 60 70 80 90 100
PWM DUTY CYCLE (%)
SUPPLY CURRENT vs. SUPPLY VOLTAGE
(4 LEDs, LED1 OPEN FOR 1.5X ONLY MODE)
120
100
15mA/LED,
80
EN1 = EN2 = V_IN
60
10mA/LED, EN1 = V_IN,
EN2 = GND
40
5mA/LED, EN1 = GND,
20
EN2 = V_IN
0
2.5 3.0 3.5 4.0 4.5 5.0
SUPPLY VOLTAGE (V)
4 _______________________________________________________________________________________