TPS62160-Q1 Datasheet, PDF (14/32 Pages) Texas Instruments – 3-V to 17-V 1-A Step-Down Converter with DCS-Control

TPS62160-Q1
SLVSCK6 – DECEMBER 2014
www.ti.com
9.2.2.3 Output Filter And Loop Stability
The TPS62160-Q1 is internally compensated to be stable with L-C filter combinations corresponding to a corner
frequency to be calculated with Equation 10:
space
ƒ_LC = _2p
1
L´C
(10)
space
Proven nominal values for inductance and ceramic capacitance are given in Table 2 and are recommended for
use. Different values may work, but care has to be taken on the loop stability which might be affected. More
information including a detailed L-C stability matrix can be found in SLVA463.
The TPS62160-Q1 includes an internal 25-pF feedforward capacitor, connected between the VOS and FB pins.
This capacitor impacts the frequency behavior and sets a pole and zero in the control loop with the resistors of
the feedback divider, per Equation 11 and Equation 12:
space
ƒ_zero
=
1
2p ´ R₁ ´ 25
pF
(11)
space
ƒ_pole
=
1
2p ´ 25
pF
æ
´ç
1
è ^R1
+
1
R₂
ö
÷
ø
(12)
space
Though the TPS62160-Q1 is stable without the pole and zero being in a particular location, adjusting their
location to the specific needs of the application can provide better performance in Power Save mode and/or
improved transient response. An external feedforward capacitor can also be added. A more detailed discussion
on the optimization for stability vs transient response can be found in SLVA289 and SLVA466.
If using ceramic capacitors, the DC bias effect has to be considered. The DC bias effect results in a drop in
effective capacitance as the voltage across the capacitor increases (see NOTE in DC Bias effect section).
9.2.3 Application Performance Plots
At V_IN = 12 V, V_OUT = 3.3 V and T_J = 25°C (unless otherwise noted)
100.0
90.0
80.0
70.0
VIN=17V
60.0
50.0
VIN=12V
40.0
30.0
VIN=6V
20.0
10.0
0.0
0.0001
0.001
0.01
0.1
1
Output Current (A)
G001
Vout = 6 V
100.0
90.0
80.0
70.0 _IOUT=1mA
IOUT=100mA
60.0
IOUT=10mA
50.0
40.0
30.0
20.0
10.0
0.0
789
Vout = 6 V
10 11 12 13 14
Input Voltage (V)
IOUT=1A
15 16 17
G001
Figure 6. Efficiency vs Output Current
Figure 7. Efficiency vs Input Voltage
14
Submit Documentation Feedback
Product Folder Links: TPS62160-Q1
Copyright © 2014, Texas Instruments Incorporated