8

Rev.1.2

10 -

COMP

VCC

OVP

LX

ISEN+

ISEN-

VSEN

R5

R6

R9

L2

2

8

3

7

4

6

5

U1

R2

D1

R3

R4

C7

+

C8

R7

LED

L3

+

C2

C1

GND

Vin

C10

+

L1

1

3

4

ELM650DA

GND

R1

C11

C5

C

C4

1

C

C6

L4

B

D D

A

E

C3

C9

2

R12

R11

R14

R13 R15

1

2

3

4

Vout+

Vout-

R8

USB

R10

Fig-4 : PC board layout guidelines

Fig-5 : The PCB layout of car charger with ELM650DA controller

Follows below PC board layout guidelines could get better performance:

1) Path A :

The Vout- is returned to input bulk capacitor C2, by passing through output capacitor C7.

2) Path B :

The output rectifier D1, together with Snubber R2 and C2, are shunt to common ground and returned to input

bulk capacitor C2.

3) Path C and D :

The decoupling capacitor C11, the compensation network R1, C4, C5, the voltage feedback network R6, R7,

C8, and the overvoltage sensing network R8, R9, are connected to IC ground, and returned to input bulk capaci-

tor C2 and output capacitor C7.

4) Path E :

Input capacitor C2 is returned to input ground, after all ground networks are following the above paths de-

signed.