Texas Instruments TPS61160(1)-243 Evaluation Module TPS61160EVM-243 TPS61160EVM-243 Datenbogen
Produktcode
TPS61160EVM-243
C
out
+
ǒ
V
out
*
V
in
Ǔ
I
out
V
out
Fs
V
ripple
V
ripple_ESR
+
I
out
R
ESR
SLVS791C – NOVEMBER 2007 – REVISED APRIL 2012
TPS61160/1 has built-in slope compensation to avoid sub-harmonic oscillation associated with current mode
control. If the inductor value is lower than 10
control. If the inductor value is lower than 10
μ
H, the slope compensation may not be adequate, and the loop can
be unstable. Therefore, customers need to verify the inductor in their application if it is different from the
recommended values.
recommended values.
Table 3. Recommended Inductors for TPS61160/1
L
DCR MAX
SATURATION CURRENT
SIZE
PART NUMBER
VENDOR
(
μ
H)
(
Ω
)
(mA)
(L × W × H mm)
LQH3NPN100NM0
10
0.3
750
3×3×1.5
Murata
VLCF5020T-220MR75-1
22
0.4
750
5×5×2.0
TDK
CDH3809/SLD
10
0.3
570
4×4×1.0
Sumida
A997AS-220M
22
0.4
510
4×4×1.8
TOKO
SCHOTTKY DIODE SELECTION
The high switching frequency of the TPS61160/1 demands a high-speed rectification for optimum efficiency.
Ensure that the diode average and peak current rating exceeds the average output current and peak inductor
current. In addition, the diode’s reverse breakdown voltage must exceed the open LED protection voltage. The
ONSemi MBR0540 and the ZETEX ZHCS400 are recommended for TPS61160/1.
Ensure that the diode average and peak current rating exceeds the average output current and peak inductor
current. In addition, the diode’s reverse breakdown voltage must exceed the open LED protection voltage. The
ONSemi MBR0540 and the ZETEX ZHCS400 are recommended for TPS61160/1.
COMPENSATION CAPACITOR SELECTION
The compensation capacitor C3 (see the
), connected from COMP pin to GND,
is used to stabilize the feedback loop of the TPS61160/1. A 220nF ceramic capacitor for C3 is suitable for most
applications.
applications.
INPUT AND OUTPUT CAPACITOR SELECTION
The output capacitor is mainly selected to meet the requirements for the output ripple and loop stability. This
ripple voltage is related to the capacitor’s capacitance and its equivalent series resistance (ESR). Assuming a
capacitor with zero ESR, the minimum capacitance needed for a given ripple can be calculated by
ripple voltage is related to the capacitor’s capacitance and its equivalent series resistance (ESR). Assuming a
capacitor with zero ESR, the minimum capacitance needed for a given ripple can be calculated by
(6)
where, V
ripple
= peak-to-peak output ripple. The additional output ripple component caused by ESR is calculated
using:
(7)
Due to its low ESR, Vripple_ESR can be neglected for ceramic capacitors, but must be considered if tantalum or
electrolytic capacitors are used.
electrolytic capacitors are used.
Care must be taken when evaluating a ceramic capacitor’s derating under dc bias, aging and AC signal. For
example, larger form factor capacitors (in 1206 size) have a resonant frequencies in the range of the switching
frequency. So the effective capacitance is significantly lower. The DC bias can also significantly reduce
capacitance. Ceramic capacitors can loss as much as 50% of its capacitance at its rated voltage. Therefore,
leave the margin on the voltage rating to ensure adequate capacitance at the required output voltage.
example, larger form factor capacitors (in 1206 size) have a resonant frequencies in the range of the switching
frequency. So the effective capacitance is significantly lower. The DC bias can also significantly reduce
capacitance. Ceramic capacitors can loss as much as 50% of its capacitance at its rated voltage. Therefore,
leave the margin on the voltage rating to ensure adequate capacitance at the required output voltage.
The capacitor in the range of 1
μ
F to 4.7
μ
F is recommended for input side. The output requires a capacitor in the
range of 0.47
μ
F to 10
μ
F. The output capacitor affects the loop stability of the boost regulator. If the output
capacitor is below the range, the boost regulator can potentially become unstable. For example, if use the output
capacitor of 0.1
capacitor of 0.1
μ
F, a 470nF compensation capacitor has to be used for the loop stable.
The popular vendors for high value ceramic capacitors are:
TDK (
Murata (
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