TPS54061 Datasheet, PDF (19/36 Pages) Texas Instruments – Wide Input 60V, 200mA Synchronous Step-Down DC-DC Converter with Low IQ

TPS54061
www.ti.com
SLVSBB7A – MAY 2012 – REVISED MAY 2012
R_COMP is calculated to be 25.9 kΩ, use the nearest standard value of 26.1 kΩ. Use Equation 24 to set the
compensation zero equal to the modulator pole frequency. Equation 24 yields a 3790 pF for capacitor C_COMP and
a 4700 pF is chosen. Use the larger value of Equation 25 and Equation 26 to calculate the C_POLE value, to set
the compensation pole. Equation 26 yields 30.5 pF so the nearest standard of 33 pF is selected.
f pole(Hz) =
Vout
1
´ Co ´ 2 ´ p
Io
(19)
f zero(Hz) =
1
R_C ´ C_O ´ 2 ´ p
(20)
f co1(Hz) = ( f zero ´ f pole)^0.5
(21)
f co2(Hz)
=
æ
çè
f sw
2
´
f
p
ole
ö^0.5
÷ø
(22)
R_COMP
=
2 ´ p ´ ¦_CO ´ C_O
gmps
´
V_OUT
V_REF ´ gmea
(23)
1
C_COMP = _{2 ´ p ´ RCOMP ´ fPOLE}
(24)
C_POLE1
=
R_C ´ C_O
R_COMP
(25)
1
C_POLE2 = _{RCOMP ´ fSW ´ p}
(26)
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