MAX8678 Maxim Integrated Products, MAX8678 Datasheet - Page 5

• Manufacturer Part Number: MAX8678
• Description: White LED Charge Pump
• Manufacturer: Maxim Integrated Products

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(V
IN
= 3.2V, R
L
= 8Ω, T
100
100
17.0
16.8
16.6
16.4
16.2
16.0
15.8
15.6
15.4
15.2
15.0
90
80
70
60
50
40
30
20
10
90
80
70
60
50
40
30
20
10
0
0
2.7
2.7
2.7
LED EFFICIENCY vs. SUPPLY VOLTAGE
LED EFFICIENCY vs. SUPPLY VOLTAGE
_______________________________________________________________________________________
4 x 1.6mA
1.6mA/LED
A
= +25°C, unless otherwise noted.)
3.0
3.0
3.0
LED CURRENT MATCHING
4 x 6.4mA
(MISMATCHED LEDs)
vs. SUPPLY VOLTAGE
SUPPLY VOLTAGE (V)
(MATCHED LEDs)
SUPPLY VOLTAGE (V)
SUPPLY VOLTAGE (V)
3.3
3.3
3.3
4 x 20.8mA
3.6
3.6
3.6
6.4mA/LED
16.4mA/LED
20.4mA/LED
4 OF 16mA/LED
3.9
3.9
3.9
Typical Operating Characteristics (continued)
White LED Charge Pump with
4.2
4.2
4.2
1.1W Audio Amplifier
V
V
ENLED
200
180
160
140
120
100
100
LED1
80
60
40
20
90
80
70
60
50
40
0
I
IN
MAX8678 EFFICIENCY vs. SUPPLY VOLTAGE
4.2
SUPPLY CURRENT vs. SUPPLY VOLTAGE
4.20
3.90
4 x 20.8mA
20.4mA/LED
4 x 1.6mA
SUPPLY VOLTAGE, TIME WEIGHTED (V)
16.4mA/LED
3.85
3.9
SHUTDOWN WAVEFORMS
(MISMATCHED LEDs)
3.80
SUPPLY VOLTAGE (V)
(MATCHED LEDs)
LED STARTUP/
3.75
3.6
3.70
6.4mA/LED
1ms/div
3.65
3.60
3.3
4 x 6.4mA
3.55
4 x 16mA
3.50
3.0
1.6mA/LED
3.40
MAX8678 toc15
3.00
2.7
2V/div
1V/div
500mA/div
5