SBOU249 December   2020 TMCS1108 , TMCS1108-Q1

 

  1.   Trademarks
  2. 1General Texas Instruments High Voltage Evaluation (TI HV EVM) User Safety Guidelines
  3. 2Overview
    1. 2.1 Kit Contents
    2. 2.2 Related Documentation From Texas Instruments
  4. 3Hardware
    1. 3.1 Features
    2. 3.2 Circuitry
      1. 3.2.1 Bypass Capacitors
      2. 3.2.2 Output Filter
      3. 3.2.3 Measurement Connector
      4. 3.2.4 Load Connectors
      5. 3.2.5 Ground Test Points
      6. 3.2.6 TMCS1108 Isolated Current-Sense Amplifier
      7. 3.2.7 Temperature Sensor
  5. 4Operation
    1. 4.1 Measurements
    2. 4.2 Advanced Measurement Tips
  6. 5Schematics, PCB Layout, and Bill of Materials
    1. 5.1 Schematics
    2. 5.2 PCB Layout
    3. 5.3 Bill of Materials

Advanced Measurement Tips

To assess whether the expected load matches the measured load, use a precision shunt resistor rated for the maximum intended current in series with the DUT. The precision shunt should have a kelvin connection where the generated sense voltage can be measured by a precision multimeter, such as the 3458a multimeter. Sensing the shunt voltage is preferred as a typical multimeter may have a current limit far below 30 A. Additionally some meters have better voltage measurement precision than current measurement precision.

For evaluating performance when the DUT is subjected to quick current pulses, use short, large-diameter wire, or short bus bars, to reduce the inductance and resistance between the hot-supply, load, and EVM. By minimizing the inductance, the rate of load slew can be increased. If assessing the performance over large transient current spikes (>30 A) is desired, be sure to use a supply with sufficient voltage headroom to accommodate the series resistance of the wires/bus bars, board planes, and DUT lead frame resistance. A large capacitor bank between the supply terminals should be used to ensure there is an adequate charge reservoir available to prevent the supply from drooping and helping supply the large current inrush through the device.

If assessing temperature performance is desired, use wide, thin bus bars to reduce the thermal sinking ability of the system and minimize the inductance of the system. While the board provides an onboard temperature sensor, board temperature may not be an exact indicator of DUT temperature. More precise measurements can be obtained by placing a layer of thermally conductive grease on top of the DUT package and placing a thermal sensor directly on the thermal grease.