Datasheet
TPS61000, TPS61001, TPS61002, TPS61003, TPS61004, TPS61005, TPS61006, TPS61007
SINGLE- AND DUAL-CELL BOOST CONVERTER WITH START-UP INTO FULL LOAD
SLVS279C – MARCH 2000 – REVISED APRIL 2003
16
POST OFFICE BOX 655303 • DALLAS, TEXAS 75265
APPLICATION INFORMATION
With those parameters it is possible to calculate the value for the inductor:
L +
V
BAT
x
ǒ
V
OUT
– V
BAT
Ǔ
∆I
L
xfxV
OUT
(4)
Parameter f is the switching frequency and ∆I
L
is the ripple current in the inductor, i.e., 20% x I
L
.
In this example, the desired inductor has the value of 12 µH. With this calculated value and the calculated cur-
rents, it is possible to chose a suitable inductor. Care has to be taken that load transients and losses in the circuit
can lead to higher currents as estimated in equation 3. Also, the losses in the inductor caused by magnetic hys-
teresis losses and copper losses are a major parameter for total circuit efficiency.
The following inductors from different suppliers were tested. All work with the TPS6100x converter within their
specified parameters:
Table 1. Recommended Inductors
VENDOR PART NUMBER
Coilcraft DO1608P Series
DS1608P Series
DO3308 Series
Coiltronics UP1B Series
UP2B Series
Murata LQH3N Series
Sumida CD43 Series
CD54 Series
CDR74B Series
TDK NLC453232T Series
capacitor selection
The major parameter necessary to define the output capacitor is the maximum allowed output voltage ripple of
the converter. This ripple is determined by two parameters of the capacitor, the capacitance and the ESR. It is
possible to calculate the minimum capacitance needed for the defined ripple, supposing that the ESR is zero.
C
min
+
I
OUT
x
ǒ
V
OUT
– V
BAT
Ǔ
fx∆VxV
OUT
(5)
Parameter f is the switching frequency and ∆V is the maximum allowed ripple.
With a chosen ripple voltage of 15 mV, a minimum capacitance of 10 µF is needed. The total ripple will be larger
due to the ESR of the output capacitor. This additional component of the ripple can be calculated using the fol-
lowing equation:
∆V
ESR
+ I
OUT
xR
ESR
(6)