Datasheet

SS SS
SS
REF
t I
C
V
u
CS
CS
L
V typ
R
1.2 I peak u
OUT IN
IN
OUT OUT
L
OUT IN
SW
OUT
V V min
V min
I V
I peak
V V min
2 L f
1
V

u


u u

OUT FB
HS LS
FB
V V
R R
V

u
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Table 2. TPS43061EVM-198 Performance Specification Summary (continued)
Specification Test Conditions MIN TYP MAX Unit
Peak efficiency TPS43061EVM-198, V
IN
= 12 V, I
OUT
= 2 A 97%
DCM threshold V
IN
= 9 V 360 mA
Pulse skipping threshold V
IN
= 9 V 12 mA
No load input current V
IN
= 9 V 1.3 mA
UVLO start threshold 5.3 V
UVLO stop threshold 4.3 V
1.3 Modifications
These EVMs are designed to provide access to the features of the TPS43061. Some modifications can be
made to this module. For further details please see the product data sheet.
1.3.1 Output Voltage Set Point
To change the output voltage of the EVM, it is necessary to change the value of resistor R8. The value of
R8 for a specific output voltage can be calculated using Equation 1, where R
HS
is R8, R
LS
is R9 and V
FB
is
1.22 V. It s recommended to use a value of R9 near 10 kΩ.
(1)
Note: V
IN
must be in a range so the minimum on-time is greater than the typical 100 ns and the minimum
off-time is greater than the largest of typical 250 ns and 5% of the switching period.
1.3.2 Current Sensing
The default configuration of the EVM is for resistor current sensing. R13 and R14 are populated with R15
open. When adjusting the input voltage, output voltage or desired maximum output voltage, the current
sense resistors R16 and R17 may need to be adjusted. The peak inductor current should first be
calculated with Equation 2. Equation 3 is then used to calculate the required current sense resistor where
V
CS
typ is the current sense threshold. V
CS
typ should be determined from the TPS43061 data sheet with
the maximum duty cycle in the application. Ensure the current sense resistor is rated for the expected
power dissipation. For inductor DCR current sensing, R14 should be left open while R15, R16 and R17
are shorted.
(2)
(3)
1.3.3 Slow-Start Time
Adjust the slow-start time by changing the value of C7. Equation 4 can be used to calculate the required
capacitance based on a desired slow-start time, t
SS
. I
SS
is the charging current of 5-µA typical and V
REF
is
the internal reference voltage of 1.22 V. The EVM is set for a slow-start time of 25 ms using C7 = 0.1 µF.
(4)
4
Using the TPS43061 Boost Evaluation Module (EVM) SLVU799A–November 2012–Revised March 2013
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