Shindengen Electric MFG.CO.,LTD

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6.5 Notes on pattern design

Patterns must be as short as possible to make the loops as small as possible. Keep the following in mind at the design

stage:

6.5.1 Pattern design for primary side

6.5.2 Pattern design around Nc coil

C106

C112

MR4000

3

5

9

R114

4

3

C113

D112

MR4000

A high-speed switching current flows through the

loop. Reducing the loop area will reduce noise.

Make the loop connecting the transformer, D112,

and C113 thick and short.

6.5.3 Pattern design for secondary side

6.5.4 Pattern design around GND pin

D201

Short

Short

L201

C202

C201

Place as close to the

output pin as possible.

Make the loop connecting the transformer,

rectification diode, and output capacitor thick and

short. Place the capacitor at the rear of the output

choke coil as close to the output pin as possible.

Connect the GND pin (Pin 3) directly to the

negative side of C106. Do not connect any other

component. Do not place the end of the control

circuit inside R114 (closer to GND pin).

6.5.5 Connecting a capacitor

6.5.6 Pattern of C114

Make sure the pattern passes through the

capacitor pads.

The Z/C pin (Pin 1) is susceptible to noise.

Connect the pattern near the Z/C pin (Pin 1) and

GND pin (Pin 3).

6. Supplementary design information