Ultra-Efficient Charge Pumps for
Six White/RGB LEDs in 3mm x 3mm Thin QFN
7/MAX648
1μF
1μF
1μF
1μF
C1P
C1N C2P
C2N
NEG
1μF
C1P
C1N C2P
C2N
NEG
1μF
INPUT
2.7V TO 5.5V
INPUT
2.7V TO 5.5V
IN
IN
EP
1μF
EP
1μF
GND
WHITE OR
RGB LED
GND
WHITE OR
RGB LED
MAX8648
D1
D2
D3
D4
D5
D6
MAX8647
D1
D2
D3
D4
D5
D6
LED1
LED2
LED3
LED4
LED5
LED6
LED1
LED2
LED3
LED4
LED5
LED6
2
SDA
SCL
I C PORT
ON/OFF AND
BRIGHTNESS
ENA
ENB
ENC
SERIAL-
PULSE
INTERFACE
V
LOGIC
1.7V TO 5.5V
V
DD
0.1μF
Figure 5. MAX8647 Typical Application Circuit
Figure 6. MAX8648 Typical Application Circuit
1μF
1μF
C1P
C1N C2P
C2N
NEG
1μF
INPUT
2.7V TO 5.5V
IN
EP
1μF
GND
WHITE OR
RGB LED
V1
V2
V3
MAX8648
D1
LED1
LED2
LED3
LED4
LED5
LED6
D2
D3
D4
D5
D6
ENA
ENB
ENC
SERIAL-
PULSE
INTERFACE
RED CHARGE
INDICATOR
Figure 7. Driving LEDs with Multiple Supplies
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MAXIM [ MAXIM INTEGRATED PRODUCTS ]
