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3.4
Using an External 5-V Supply (R32 and R33)
4
Test Setup
4.1
Equipment
Test Setup
For more details on setting V
Ilim
for specific overcurrent protection levels, see the overcurrent protection
equations in the Functional Descriptions section of the TPS40130 data sheet.
The TPS40130EVM-001 is designed to be run from a single 12-V supply by incorporating a TL751 5-V
LDO, however an external supply can be used if a separate 5-V bus is available in the target system. To
use an external 5-V supply, connect it through 5V_IN (J7) and remove R32 and R33 to disconnect the
LDO from the circuit. The TPS40130EVM-001 requires approximately 50 mA of current from the 5-V
supply.
4.1.1
Voltage Source
V
12V_IN
: The input voltage source (V
12V_IN
) should be a 0-V to 15-V variable dc source capable of 8.5 Adc.
Connect V
12V_IN
to J1 and J6 as shown in
Figure 1
.
4.1.2
Meters
A1: 0 Adc to 10 Adc ammeter
V1: V
12V_IN
, 0 V to 15 V voltmeter
V2: V
1V5_OUT
VOUT, 0 V to 5 V voltmeter
4.1.3
Loads
LOAD1: The output load (LOAD1) should be an electronic constant current mode load capable of 0 Adc to
40 Adc at 1.5 V.
4.1.4
Recommended Wire Gauge
V
12V_IN
to J1 and J6: The connection between the source voltage, V
12V_IN
and J1 and J6 of HPA087 can
carry as much as 7 Adc. The minimum recommended wire size is AWG #16 with the total length of wire
less than 4 feet (2 feet input, 2 feet return).
J4 to LOAD1: The connection between J4 of HPA087 and LOAD1 can carry as much as 40 Adc. The
minimum recommended wire size is 4 x AWG #16, with the total length of wire less than 1 foot.
J2 and J5 to LOAD1: The connection between J2 and J5 of HPA087 and LOAD1 can carry as much as
40 Adc. The minimum recommended wire size is 2 x AWG #16 (two wires per connector), with the total
length of wire less than 1 foot.
12-V Input, 1.5-V Output, 40-A Two Phase Synchronous Buck Converter Using the TPS40130
SLUU208 – October 2004
7
