IL44608 Datasheet, PDF(10/13 Page) IK Semicon Co., Ltd – External Components Reliable and Flexible SMPS Controller

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IL44608 Datasheet, PDF (10/13 Pages) IK Semicon Co., Ltd – External Components Reliable and Flexible SMPS Controller

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IL44608N

EQUATION 8

d BM = ï£±

ï£´

ï£®

ï£¯

ï£¬ï£«

ï£·ï£¶ï£ºï£¹ï£´ï£¼

ï£´ï£´ï£´ï£²ï£¬ï£¬ï£ï£« k1 +

ï£´ï£´ï£³

I stup

ï£·ï£¶

ï£·ï£¸

ï£¯

ï£¯k S/Stup

ï£¯

ï£°

ï£¬

ï£¬ k S/L

ï£¬

ï£¬ï£¬ï£

ï£¬ï£« I pin3

ï£¬ï£ Istup

ï£·ï£¶

ï£·ï£¸

ï£·ï£·ï£ºï£ºï£´ï£´ï£½

ï£·ï£ºï£´

ï£·ï£·ï£¸ï£ºï£»ï£´ï£´ï£¾

where: k1 = Iccs/Istup

k2 = IccL/Istup

kS/Stup = (VstupâUVLO2)/(VstupâUVLO1)

kS/L = (UVLO1âUVLO2)/(VstupâUVLO1)

PULSED MODE CURRENT SENSE CLAMPING LEVEL

Equations 9, 10, 11 and 12 allow the calculation of the Rcs value for the desired maximum current peak value during the

SMPS standâby mode.]

EQUATION 9

Ipk stby

Vcsâ th

â (R cs

Ã Ics )

where: Vcsâth is the CS comparator threshold

Ics is the CS internal current source

RS is the sensing resistor

Rcs is the resistor connected between pin 2 and RS

EQUATION 10

Ipk stby

Vcsâth

ï£¬ï£¬ï£ï£«

I cs

Vcs â th

ï£·ï£·ï£¸ï£¶

EQUATION 11

( ) Ipkstby

= Vcsâth

1â

R cs Ã Ycsâstby

where: Ycsâstby = Ics/Vcsâth

Taking into account the circuit propagation delay (Î´tcs) and the Power Switch reaction time (Î´tps):

EQUATION 12

( ) Ipkstby

ï£®

1â

= ï£¯Vcsâth Ã

ï£°

R cs Ã Ycsâstby

ï£¹

ï£º

ï£»

Vin

(Î´ t cs

+ Î´t ps )

2011, February, Rev. 01

▷