MAX8822 Maxim Integrated Products, MAX8822 Datasheet - Page 5

• Manufacturer Part Number: MAX8822
• Description: Ultra-Efficient Negative Charge-Pump LED Driver
• Manufacturer: Maxim Integrated Products

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(V
Driver with Dual LDOs in 3mm x 3mm Thin QFN
IN
= 3.6V, V
V
ENLED
EN_
I
17.0
16.8
16.6
16.4
16.2
16.0
15.8
15.6
15.4
15.2
15.0
I
LED1
LED1
V
Ultra-Efficient Negative Charge-Pump LED
I
I
IN
IN
IN
2.7
= V
TYPICAL OPERATING WAVEFORMS
_______________________________________________________________________________________
IN
3.1
, Circuit of Typical Operating Circuit , T
LED CURRENT MATCHING
SERIAL-PULSE CONTROL
(CHARGE PUMP ACTIVE)
vs. SUPPLY VOLTAGE
DIMMING RESPONSE
3.5
SUPPLY VOLTAGE (V)
3.9
400ns/div
1ms/div
16mA/LED, V
24mA
4.3
4 LEDs, 24mA/LED,
V
IN
= 3.2V
4.7
IN
FALLING
7 PULSES
MAX8822 toc14
MAX8822 toc12
5.1
14.4mA
4 LEDs
Typical Operating Characteristics (continued)
5.5
50mA/div
5V/div
0V
10mA/div
0A
0A
10mV/div
(AC-COUPLED)
100mA (AC-COUPLED)
10mA/div
24mA (AC-COUPLED)
10mA/div
A
= +25°C, unless otherwise noted.)
I
LED_TOTAL
V
V
ENLDO
I
I
I
ENLED
LDO2
LDO1
LED1
V
I
V
IN
I
IN
IN
IN
TYPICAL OPERATING WAVEFORMS
0
SERIAL-PULSE CONTROL LDO
8 PULSES
(CHARGE PUMP INACTIVE)
VOLTAGE PROGRAMMING
STARTUP AND SHUTDOWN
400μs/div
400ns/div
1ms/div
I
LDO1
4 LEDs, 24mA/LED,
V
IN
= I
= 3.8V
I
LDO2
LED_
= 100mA
MAX8822 toc11
MAX8822 toc15
= 24mA
MAX8822 toc13
2V/div
10mV/div
(AC-COUPLED)
5V/div
1.8V
1V/div
0V
3.3V
0V
100mA (AC-COUPLED)
10mA/div
24mA (AC-COUPLED)
10mA/div
100mA/div
100mA/div
5V/div
0V
24mV/div
(AC-COUPLED)
0A
0A
5