VIPER53EDIP-E datasheet(17/31 Pages) STMICROELECTRONICS

Part #	VIPER53EDIP-E

Description	OFF-line Primary Switch

PDF	31 Pages

Scroll/Zoom	100%

Manufacturer	STMICROELECTRONICS [STMicroelectronics]

Direct Link	http://www.st.com

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17 / 31 page

VIPer53EDIP - E / VIPer53ESP - E

Regulation Loop Stability

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17/31

The lowest load gives another condition for stability: The frequency FBW1 must not

encounter the third order slope generated by the load pole, the R1-C1 network on the

COMP pin and the R2-C2 network at the level of the TL431 on secondary side. This

condition can be met by adjusting both C1 and C2 values:

The above formula gives a minimum value for C1. It can be then increased to provide a

natural soft start function as this capacitor is charged by the current ICOMP at start-up.

OUT

⋅

6.3

--------- R1

⋅⋅

-----------------------------------

OU T1

MAX

---------------------

⋅

OUT

⋅

6.3

--------- R

⋅⋅

⋅

-----------------------------------------------

OU T1

MAX

---------------------

⋅

OUT1

OUT

-------------------

with:

VIPER53EDIP-E Datasheet(PDF) 17 Page - STMicroelectronics