The UCC34141EVM-116
utilizes screw terminals for quickly connecting to VIN, VDD and VEE. Connecting
the appropriate ammeters and voltmeters, as shown in Figure 2‑1, allows accurate EVM
efficiency measurements to be made.
Connecting test equipment:
- Move shunt jumper, SH-J1 into the J2,
1-2, EN OFF position. This assures the EVM cannot start while test equipment is being
connected.
- Connect a +5V DC bias power supply J1:1-2
(+3.3V to +5V). Set the power supply to 0V. The +5V supply at J1 will serve as the pullup
bias for /PG and ENA. Turn off/disable the +5V DC Bias power supply.
- Connect the VIN DC power
supply capable of 5V<VIN<20V, 500mA at J3:1-2 (VIN). Adjust
the power supply to 12V, and set the current limit to 1A. Turn off/disable the
VIN power supply.
- Connect a variable load between J4:1
(VDD) and J4:2 (COM). If using an electronic load, set to constant resistance (CR), 650Ω
(~500mW). Leave the load disabled until the EVM is powered.
- Connect a second load between J4:2 (COM)
and J4:3 (VEE). If using an electronic load, set to constant resistance (CR), 250Ω
(~10mW). Leave the load disabled until the EVM is powered. Since the required load is
small, a through-hole, 500mW, load resistor can be connected between J4:2-3.
- 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 2‑1. A current probe can be used with
the oscilloscope to verify the stability of the DC current being regulated by an
electronic load.
Power on for start-up:
- Verify VIN and +5V DC Bias
power supplies are off/disabled and no voltage is applied to the UUT
- Move shorting jumper, SH-J1, into the
J2:2-3, EN ON position. NOTE: removing the shorting jumper, SH-J1 also results in EN
ON.
- Turn on the VIN DC power
supply. Verify 12V is present at TP1-to-TP3
- Verify the loads on VDD and VEE are
disabled
- Turn on the +5V DC bias power supply. EVM
is now enabled with VDD and VEE in regulation under no load condition.
- Verify +18V present on VDD-COM, and -5V
present on VEE-COM
- Enable the load on VDD, enable the load
on VEE
- The UCC35341-Q1 is now regulating VDD and
VEE and processing ~0.5W of isolated output power
- Vary VIN between
5V<VIN<20V, vary IVDD between
0mA<IVDD<112mA, Vary IVEE between
0mA<IVEE<6mA.
- Insert oscilloscope probes into TP9, TP10
and TP11 for measuring VEE, VDD and VIN startup, steady state and AC ripple
voltage
Power off for shutdown:
- Move shorting jumper SH-J1 into the
J2:1-2, EN OFF position
- Turn off +5V, DC bias power supply
- Disable IVDD load
- Disable IVEE load
- Turn off VIN power supply