The UCC14131EVM-070 EVM utilizes screw terminals for quickly connecting to VIN, VDD, [+5V] and VEE (refer to Table 4-1). Connecting the appropriate ammeters and voltmeters, as shown in Figure 4-1, allows accurate EVM efficiency measurements to be made.
Connecting Test Equipment
- Move jumper SH-J1 into the J2:1-2, EN OFF position. This makes sure the EVM cannot start while test equipment is being connected.
- Connect a 5-V DC bias power supply to 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 5-V DC Bias power supply.
- Connect the VIN DC power supply capable of 8 V<VIN<18 V, 300 mA at J4:1-2 (VIN). Adjust the power supply to 12 V, and set the current limit to 350 mA. Set the power supply voltage to 12 V. Turn off/disable the VIN power supply.
- Connect a variable load between J3:1 (VDD) and J3:3 (VEE). If using an electronic load, set to constant current (CC), 68 mA. Leave the load disabled until the EVM is powered.
- Connect a second load between J3:2 ([+5V]) and J3:3 (VEE). If using an electronic load, set to constant current (CC), 10 mA. Leave the load disabled until the EVM is powered. Since the required load is small, a through-hole, 250-mW, 400-Ω load resistor can be connected between J3:2-3.
- Some electronic loads are not be able to regulate/stabilize CC when setting in the low mA range. Monitor the input current and load currents by inserting ammeters, A1-A3, 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.