SLUUBG8C November   2018  – October 2021 UCC20520 , UCC21320-Q1 , UCC21520 , UCC21520-Q1 , UCC21521 , UCC21530

 

  1.   Trademarks
  2. 1 Introduction
  3. 2 Description
  4. 3 Features
    1. 3.1 I/O Description
    2. 3.2 Jumpers (Shunt) Setting
  5. 4 Electrical Specifications
  6. 5 Test Summary
    1. 5.1 Definitions
    2. 5.2 Equipment
      1. 5.2.1 Power Supplies
      2. 5.2.2 Function Generators
    3. 5.3 Equipment Setup
      1. 5.3.1 DC Power Supply Settings
      2. 5.3.2 Digital Multi-Meter Settings
      3. 5.3.3 Two-Channel Function Generator Settings
      4. 5.3.4 Oscilloscope Setting
      5. 5.3.5 Jumper (Shunt) Settings
      6. 5.3.6 Bench Setup Diagram
  7. 6 Power-Up and Power-Down Procedure
    1. 6.1 Power Up
    2. 6.2 Power Down
  8. 7 Test Waveforms (CL=0pF) With Different DT Configurations
    1. 7.1 DT Connected to VCCI (J-DT Option B in Table 1-1 )
    2. 7.2 DT Pin Floating or Left Open (J-DT Option A in Table 1-1 )
    3. 7.3 DT Pin Connected to RDT (J-DT Option C in Table 1-1 )
  9. 8 Schematic
  10. 9 Layout Diagrams
  11. 10List of Materials
  12. 11Revision History

7.3 DT Pin Connected to RDT (J-DT Option C in Table 3-2)

The dead time (DT) between the outputs of the two channels is set according to: DT (in ns) = 10 × RDT (in kΩ).

The steady-state voltage at DT pin is around 0.8 V, and the DT pin current will be less than 10 µA when RDT = 100 kΩ. Therefore, TI recommends to parallel a ceramic bypass capacitor (2.2 nF or above) with RDT to achieve better noise immunity and better dead-time matching between two channels, especially when the dead time is larger than 300 ns. The major consideration is that the current through the RDT is used to set the dead time, and this current decreases as RDT increases. This bypass capacitor is not installed in the EVM, but the user can easily install it on the bottom layer where the RDT is located.

GUID-D18F7477-EA7F-484E-9959-408FA63F1C3F-low.gifFigure 7-3 Test Waveforms if DT Connected to RDT (Channel 3 and 4 is PWM Inputs, and Channel 1 and 2 is Driver Outputs)