2-Channels Secondary Monitoring IC

Version

：A.002

-9-

PS235S

Brown out function

When AC power decrease, the AC line current will increase, it may cause power coil

damage. So PS235S provides the brown out function to avoid the power supply

damaged. When PSON logic low, it monitor PGI5 and PSON logic high, it monitor

PGI12. If PGI signal < 1.22, the delay block active (2600mS), FPO will latch.

OCP setting

ground through a 62.5KΩ resistor. RI pin is a reference current generator and it can

adjust the over current trigger point. The OCP monitors the channel pass current with

VS and IS pins according to Ohm law. We hereby list the formulas for design OCP

trigger point;

1. Over-Current Protection design example:

(1) Set

A

I

ref

μ

20

=

, so

()

Ω

=

=

=

K

I

V

R

RI

RI

I

5

.

63

20

27

.

1

μ

ref

OC

V

V

I

R

I

V

×

×

=

×

=

Δ

+

8

005

.

0

12

12

12

(3) If +12V OCP trip point is 20A,

()

Ω

=

×

×

=

625

20

8

20

005

.

0

12

μ

OC

R

2. It is recommended that R-C filters be connected to VS and IS pin, which increases

the accuracy of OCP.

GND path

The GND path width should be made as wide as possible.

The better grounding ability, the better performance during the surge test.