The UCC14240EVM-052 EVM uses screw
terminals for quickly connecting to the VIN, VDD ,and VEE pins. Connect the
appropriate ammeters and voltmeters, as shown in Figure 4-1, to get accurate EVM efficiency measurements.
Connecting Test Equipment
- Move jumper J3 into the 1-2, EN
OFF position. This assures the EVM cannot start while test equipment is being
- Connect a +5 V DC bias power
supply J1:1-2 (+3.3 V to +5 V). Set the power supply to 0 V. The +5 V supply at
J1 serves as the pullup bias for /PG and ENA. Turn off/disable the +5V DC Bias
- Connect the VIN DC power supply
capable of 21 V<VIN<27 V, 200 mA at J5:1-2 (VIN). Adjust the power supply
to 24 V, and set the current limit to 300 mA. Set the power supply to 24 V. Turn
off/disable the VIN power supply.
- Connect a variable load between
J2:1 (VDD) and J2:3 (VEE). If using an electronic load, set to constant current
(CC), 80 mA. Leave the load disabled until the EVM is powered.
- Connect a second load between
J2:2 (COM) and J2:3 (VEE). If using an electronic load, set to constant current
(CC), 10 mA. Leave the load disabled until the EVM is powered.
- Some electronic loads may not be
able to regulate/stabilize CC when setting in the low mA range. Monitor the
input current and load currents by inserting ammeters as shown in Figure 4-1. Use a current probe with the oscilloscope to verify the
stability of the DC current being regulated by an electronic load.
Figure 4-1 Typical Efficiency Measurement