AAT3153 查看數據表（PDF） - Analog Technology Inc

零件编号

产品描述 (功能)

比赛名单

AAT3153

High Efficiency 1X/1.5X/2X Charge Pump For White LED Applications

Analog Technology Inc 

AAT3153

High Efficiency 1X/1.5X/2X Charge Pump

For White LED Applications

S2Cwire Serial Interface Timing

EN/SET

Code OFF

tHI

tLO

1

2

tOFF

3

OFF

Auto-Disable Feature

The AAT3153 is equipped with an "auto-disable"

feature for each LED channel. After the IC is

enabled and started up, a test current of 10µA (typ-

ical) is forced through each sink channel. The

channel will be disabled if the voltage of that par-

ticular SINK pin does not drop to certain threshold.

This feature is very convenient for disabling an

unused channel or during an LED fail short event.

Thermal Protection

The AAT3153 has a built-in thermal protection cir-

cuit that will shut down the charge pump if the die

temperature rises above the thermal limit, as is the

case during a short circuit of the VOUT pin.

Applications Information

LED Selection

Although the AAT3153 is specifically intended for

driving white LEDs, the device can also be used to

drive most types of LEDs with forward voltage

specifications ranging from 2.0V to 4.7V. LED

applications may include main and sub-LCD dis-

play backlighting, camera photo-flash applications,

color (RGB) LEDs, infrared (IR) diodes for remotes,

and other loads benefiting from a controlled output

current generated from a varying input voltage.

Since the D1 to D6 input current sinks are matched

with negligible voltage dependence, the LED

brightness will be matched regardless of the spe-

cific LED forward voltage (VF) levels. In some

instances (e.g., in high-luminous-output applica-

tions such as photo-flash), it may be necessary to

drive high-VF type LEDs. The low-dropout current-

sinks in the AAT3153 make it capable of driving

LEDs with forward voltages as high as 4.7V at full

current from an input supply as low as 3.0V.

Outputs can be paralleled to drive high-current

LEDs without complication.

Device Switching Noise Performance

The AAT3153 operates at a fixed frequency of

approximately 1MHz to control noise and limit har-

monics that can interfere with the RF operation of

cellular telephone handsets or other communica-

tion devices. Back-injected noise appearing on the

input pin of the charge pump is 20mV peak-to-

peak, typically ten times less than inductor-based

DC/DC boost converter white LED backlight solu-

tions. The AAT3153 soft-start feature prevents

noise transient effects associated with in-rush cur-

rents during start up of the charge pump circuit.

Capacitor Selection

Careful selection of the four external capacitors

CIN, C1, C2, and COUT is important because they

will affect turn-on time, output ripple, and transient

performance. Optimum performance will be

obtained when low Equivalent Series Resistance

(ESR) (<100mΩ) ceramic capacitors are used. In

general, low ESR may be defined as less than

100mΩ. A capacitor value of 1µF for all four capac-

itors is a good starting point when choosing capac-

itors. If the LED current sources are only pro-

grammed for light current levels, then the capacitor

size may be decreased.

8

3153.2004.10.0.6

Share Link: