ADP8866 Analog Devices, ADP8866 Datasheet - Page 11

• Manufacturer Part Number: ADP8866
• Description: Charge Pump Driven 9-Channel LED Driver with Automated LED Lighting Effects
• Manufacturer: Analog Devices

Specifications of ADP8866

• Vin Range: 2.5 to 5.5V
• Vout (v): 4.3 to 5.5
• Synchronous: No
• Package: 20-Lead LFCSP
• Led Configuration: Parallel
• Topology: Capacitive
• I2c Support: Yes
• Max Iout (ma): 25mA
• Brightness Control: I2C
• Peak Efficiency (%): 92%
• Switching Frequency: 1MHz

THEORY OF OPERATION
The ADP8866 combines a programmable backlight LED charge
pump driver with automatic blinking functions. Nine LED drivers
can be independently programmed at currents up to 25 mA.
The current level, fade time, and blinking rate can be programmed
once and executed autonomously on a loop. Separate fade-in
and fade-out times can be set for the backlight LEDs.
nRST
nINT
SDA
SCL
VIN
C
IN
ID1
VIN
STANDBY
NOISE FILTER
D1
nINT MUX
ID2
UVLO
50µs
I
GAIN CONTROL
2
D2
C LOGIC
ID3
RESET
INT
D3
ID4
ILED CONTROL
EN
D4
Figure 27. Detailed Block Diagram
ID5
VIN
STANDBY
Rev. 0 | Page 11 of 52
PWM
D5
V
ID6
I
REFS
REFS
D6
CURRENT
CLK
OUTPUT
ID7
LED
Driving all of this is a two capacitor charge pump with gains of
1×, 1.5×, and 2×. This setup is capable of driving a maximum
I
safety features including short-circuit, overvoltage, and over-
temperature protection allows easy implementation of a safe
and robust design. Additionally, input inrush currents are
limited via an integrated soft start combined with controlled
input to output isolation.
OUT
CHARGE
LOGIC
PUMP
of 240 mA from a supply of 2.5 V to 5.5 V. A full suite of
D7
ID8
ID1
ID2
ID3
ID4
ID5
ID6
ID7
ID8
ID9
D8
ID9
D9
(1x, 1.5x, 2x)
CHARGE
START
PUMP
SOFT
SELECT
LOGIC
GAIN
I
SS
C1+
C1–
C2+
C2–
GND
VOUT
C
C1
1µF
C2
1µF
OUT
ADP8866