AN2683 datasheet(14/38 Pages) STMICROELECTRONICS

Part #	AN2683

Description	Compact dual output point of load converter

PDF	38 Pages

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Manufacturer	STMICROELECTRONICS [STMicroelectronics]

Direct Link	http://www.st.com

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14 / 38 page

Circuit description

AN2683

14/38

for output 2:

Equation 24

With fz established the stability of the system needs to be verified. The system is stable if the

switching frequency (fsw) is greater than 4 times the corner frequency (fz) of Cout; fsw > fz x 4.

for output 1:

Equation 25

Equation 26

for output 2:

Equation 27

Equation 28

The value of Cint is actually computed three different ways. The maximum value that results

from the computations is the value that should be used. In the formulas for calculating Cint

the following constants are used: gm = 50

µs (the transconductance of the integrator

amplifier); k = 4; Vr = 0.9 V (internal reference voltage).

π 247µF 15.54mΩ

⋅⋅

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

41.46kHz

50.56kHz

202.2kHz

⋅

202.2kHz

300kHz

41.46kHz

⋅

165.8kHz

400kHz

AN2683 Datasheet(PDF) 14 Page - STMicroelectronics