Datasheet

1 1
150
20 20 14.5 7.50
HF
COMP
C pF
fco R kHz k
= = =
p ´ ´ p ´ ´ W
22 5
14.7
7.50
OUT
HF
COMP
C ESR
F m
C pF
R k
´
m ´ W
= = =
W
= = = = m
p ´ ´ p ´ ´ W
COMP
COMP
C C F
fco kHz
R k
9
1 1
0.0147
14.5
2 2 7.50
10 10
OUT SENSE OUT SH SL
COMP
SL IN
C R V co R R
R R
R V Gea
F m V kHz k k
k
A
k V
V
7
2 ( )
40
3 min
40 2 22 10 15 14.5 (124 11 )
7.45
3
11 6 1100
fp ´ ´ ´ ´ ´ +
= = ´
´ ´
p ´ m ´ W ´ ´ ´ W + W
= ´ = W
m
W ´ ´
750
2 150
5 5
SW
f
kHz
fco kHz< = =
57.9
1 14.5
4 4
RHPZ
f
kHz
fco kHz< = =
2
2
15
6
2
57.9
2 2 3.3 15
OUT
OUT IN
RHPZ
OUT
V
V
I V
V
A
f kHz
L V H V
æ ö
æ ö
= ´ = ´ =
ç ÷
ç ÷
p´ p´ m
è ø
è ø
mod
1 1
1.45
2 2 5 22
Z
OUT
f MHz
ESR C m F
= = =
p ´ ´ p ´ W ´ m
mod
1 1
0.97
15
2 22
2
2
P
OUT
OUT
OUT
f kHz
V V
F
C
A
I
= = =
p ´ ´ m
p ´ ´
min
3 3 6
11.3
40 2 40 2 10 2
IN
SENSE OUT
V
V V
Adc
R I m A V
= ´ = ´ =
´ ´ ´ W ´
TPS43060
TPS43061
www.ti.com SLVSBP4C –DECEMBER 2012–REVISED SEPTEMBER 2013
boost topology the maximum crossover frequency is typically limited by the right-half plane zero (RHPZ). The
RHPZ can be estimated with Equation 40. The compensation design should be done at the minimum input
voltage when the RHPZ is at the lowest frequency. The crossover frequency should also be limited to less than
1/5 of the switching frequency. Equation 41 and Equation 42 are used to calculate the maximum recommended
crossover frequency. For this example design, Adc = 11.3 V/V, ƒ
Pmod
= 0.97 kHz, ƒ
Zmod
= 1.45 MHz, ƒ
RHPZ
= 57.9
kHz, ƒco1 = 14.5 kHz, and ƒco2 = 150 kHz. The target fco is 14.5 kHz.
(37)
(38)
(39)
(40)
(41)
(42)
The compensation components can now be calculated. A resistor in series with a capacitor creates a
compensating zero. A capacitor in parallel to these two components can be added to form a compensating pole.
To determine the compensation resistor (R7) use Equation 43. R7 is calculated to be 7.45 kΩ and a standard 1%
value of 7.50 kΩ is selected. Use Equation 44 to set the compensation zero to 1/10 the target crossover
frequency. C9 is calculated at 0.0147 µF and a standard value of 0.015 µF is used.
(43)
(44)
A compensation pole can be implemented if desired with capacitor C8 in parallel with the series combination of
R7 and C9. Use the larger value calculated from Equation 45 and Equation 46. The selected value of C8 is 150
pF for this example.
(45)
(46)
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