
Ultra-Efficient Charge Pumps for
Six White/RGB LEDs in 3mm x 3mm Thin QFN
Typical Operating Characteristics (continued)
(V IN = 3.6V, V EN_ = V IN , circuit of Figure 1, T A = +25°C, unless otherwise noted.)
1x MODE OPERATING WAVEFORMS
1.5x MODE OPERATING WAVEFORMS
30
25
LED CURRENT vs. TEMPERATURE
V IN
(V IN = 4V)
MAX8647/48 toc14
AC-COUPLED
100mV/div
V IN
(V IN = 3V)
MAX8647/48 toc15
AC-COUPLED
100mV/div
20
I IN
100mA/div
15
I IN
100mA/div
10
0A
20mA/div
0A
20mA/div
5
I LED
ALL LEDs ON
0A
I LED
ALL LEDs ON
0A
0
I LED = 24mA
I LED = 24mA
-40
-15
10
35
60
85
400ns/div
400ns/div
TEMPERATURE ( ° C)
STARTUP AND SHUTDOWN
(MAX8648)
MAX8647/48 toc16
SINGLE-WIRE PULSE DIMMING
(MAX8648)
MAX8647/48 toc17
V EN_
ENA = ENB = ENC
2V/div
V EN_
OPERATING IN 1x
5V/div
MODE, ALL 6 LEDs
AC-COUPLED
OPERATING
V IN
20mV/div
I IN
I LED5
1ms/div
LINE-TRANSIENT RESPONSE
(V IN = 4.3V TO 3.8V TO 4.3V)
MAX8647/48 toc18
200mA/div
0A
2V/div
0A
4.3V
TOTAL I LED5
20mA/div
0A
10ms/div
LINE-TRANSIENT RESPONSE WITH MODE
CHANGE (V IN = 3.8V TO 3.4V TO 3.8V)
MAX8647/48 toc19
V IN
I IN
3.8V
200mA/div
0A
V IN
I IN
3.8V
3.4V
200mA/div
0mA
24mA
I LED6
1ms/div
20mA/div
I LED6
1ms/div
24mA
20mA/div
6
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