Datasheet

= + ´
J A TH TOT
T T R P
= ´ ´ ´
TOT COND SW GD Q
P P P P P
-
= ´ ´
6
Q IN
P 116 10 V
9
GD IN SW
P V 3 10 f
-
= ´ ´ ´
( )
2
9
SW IN SW OUT
P V I 0.25 10f
-
= ´ ´ ´ ´
( )
( )
æ ö
= ´ ´
ç ÷
è ø
2
OUT
COND OUT
DS on
IN
V
P I R
V
( )
C
Z mod
1
C
2 R
f
f
=
p ´ ´
( )
C
C
P mod
1
C
2 R f
=
p ´ ´
( ) ( ) ( )
OUT
C
REF
MOD c Z mod EA
V
R
G gm V
f
f
=
´ ´ ´
OUT ESR
C
C R
C
R
f
´
=
( )
C
C
P mod
1
C
2 R f
=
p ´ ´
TPS54160 , TPS54160A
SLVSB56C –MAY 2012–REVISED FEBRUARY 2014 www.ti.com
(49)
(50)
For cases where the modulator zero is less than the crossover frequency (Aluminum or Tantalum capacitors), the
equations are:
(51)
(52)
(53)
For the example problem, the ESR zero is located at a higher frequency compared to the crossover frequency so
Equation 50 through Equation 53 are used to calculate the compensation components. In this example, the
calculated components values are:
• R
C
= 76.2 kΩ
• C
C
= 2710 pF
• Cƒ = 6.17 pF
The calculated value of the Cf capacitor is not a standard value so a value of 2700 pF is used. 6.8 pF is used for
C
C
. The R
C
resistor sets the gain of the error amplifier which determines the crossover frequency. The calculated
R
C
resistor is not a standard value, so 76.8 kΩ is used.
9.2.2.11 Power Dissipation Estimate
The following formulas show how to estimate the device power dissipation under continuous conduction mode
(CCM) operation. These equations should not be used if the device is working in discontinuous conduction mode
(DCM).
The power dissipation of the device includes conduction loss (Pcon), switching loss (Psw), gate drive loss (Pgd)
and supply current (Pq).
(54)
(55)
(56)
where
• I
OUT
is the output current (A)
• R
DS(on)
is the on-resistance of the high-side MOSFET (Ω)
• V
OUT
is the output voltage (V)
• V
IN
is the input voltage (V)
• ƒ
SW
is the switching frequency (Hz) (57)
(58)
For given T
A
,
(59)
For given T
JMAX
= 150°C
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