Preliminary Datasheet

LP3352

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LP3352 Version 0.2 AUG-2018

Application Information (Continued)

LED Open Protection

If one of the LED strings is open at any time, the boost

converter output voltage rises to the OVP threshold

during

the

start-up

period

before

the

LP3352

auto-detect the open LED string. The controller

removes the open CHx pin and continues to regulate

current for the other strings.

LED Short Protection

If there are several shorted LEDs in one string, that

total voltage will smaller than other LED strings and

the voltage on the affected CHx pin will be higher than

on the other CHx pins. If any CHx pin voltage exceeds

CHx

OVP

threshold,

the

IC

turns

off

the

corresponding current sink and removes this CHx pin

from regulation loop, the other CHx pins’ current

regulation is not affected. This state will keep until the

chip is power restart or EN cycled.

Layout Guideline

The proper PCB layout and component placement are

critical for all circuit. The careful attention should be

prevent electromagnetic interference (EMI) problems.

Here are some suggestions to the layout of LP3352

design.

1.

Connected

all

ground

together

with

one

uninterrupted ground plane with at least two vias .

2. The input capacitor should be located as closed as

possible to the VIN and ground plane.

3. Minimize the distance of all traces connected to the

LX node, that the traces short and wide route to obtain

optimum efficiency.

4. All output capacitor must be closed to ground

plane. The ground terminal of COUT must be located

as closed as possible to ground plane.

5. Radiated noise can be decreased by choosing a

shielded inductor.

PGND

LX

VIN

OUT

CTRL

CH4

AGND

CH3

1

2

3

EP

ISET VL CH1

CH2

NC EN CH6

CH5

4

5

6

7

8

9

10

12

11

13

14

15

16

VIN

VOUT GND

GND

Figure 5. Recommended PCB Layout Diagram

.