Datasheet

R1=
(
)
V
O
¾
0.765+
VFB1
(ripple)
¾
2
-1
· R2
(FSEL =GND)
1
R1=
(
)
V
O
¾
0.758+
VFB1
(ripple)
¾
2
-1
· R2
(FSEL = V5FILT)
1
( )
IN O
O
TRIP OCL DS(ON)
sw IN
V V
V
V = I R
2 L1 V
æ ö
-
- · ·
ç ÷
ç ÷
· · ¦
è ø
TRIP OCLoff
TRIP
TRIP
V (mV) V
R (k ) =
I ( A)
-
W
m
T
SS
=
C
7
0.765·
¾
2e
-6
( )s
(FSEL =GND)
T
SS
=
C
7
0.758·
¾
2e
-6
( )s
(FSEL = V5FILT)
P f CiH CiL VREG V
d SW in(max)
= ( + ) 5· · ·
TPS53114
www.ti.com SLVS887B –APRIL 2009–REVISED OCTOBER 2010
CHOOSE BOOTSTRAP CAPACITOR
The TPS53114 requires a bootstrap capacitor from SW to VBST to provide the floating supply for the high-side
drivers. A minimum 0.1-mF high-quality ceramic capacitor is recommended. The voltage rating should be greater
than 10.0 V.
CHOOSE VREG5 AND V5FILT CAPACITOR
The TPS53114 requires both the VREG5 regulator and V5FILT input are bypassed. A minimum 4.7-mF
high-quality ceramic capacitor must be connected between the VREG5 and GND for proper operation. A
minimum 1.0-mF high-quality ceramic capacitor must be connected between the V5FILT and GND for proper
operation. Both of these capacitors' voltage ratings should be greater than 10 V.
CHOOSE OUTPUT VOLTAGE RESISTORS
The output voltage is set with a resistor divider from output voltage node to the VFBx pin. It is recommended to
use 1% tolerance or better resistors. Select R2 between 10 kΩ and 100 kΩ and use Equation 11 or Equation 12
to calculate R1.
(11)
(12)
Where:
VFB1
(ripple)
= Ripple voltage at VFB1
CHOOSE RESISTOR SETTING FOR OVER CURRENT LIMIT
(13)
(14)
Where:
• R
DS(ON)
= Low side FET on-resistance
• I
TRIP
= TRIP pin source current （≉ 10 mA）
• V
OCLoff
= Minimum over current limit offset voltage (-20 mV)
• I
OCL
= over current limit
CHOOSE SOFT START CAPACITOR
Soft start timing equations are as follows:
(15)
(16)
CHOOSE PACKAGE OPTION
TPS53114 power dissipation:
(17)
Where:
• C
iH
= Input capacitor of high side MOSFET
• C
iL
= Input capacitor of low side MOSFET
Choose package considering the Dissipation Rating table.
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