TIDUF59 March   2024

 

  1.   1
  2.   Description
  3.   Resources
  4.   Features
  5.   Applications
  6.   6
  7. 1System Description
    1. 1.1 Key System Specifications
  8. 2System Overview
    1. 2.1 Block Diagram
    2. 2.2 Design Considerations
      1. 2.2.1 PFC Inductance Design
      2. 2.2.2 Configuration of CS pin in LMG3622
      3. 2.2.3 AHB Topology and the VCC Design
      4. 2.2.4 LMG2610 for AHB Topology
    3. 2.3 Highlighted Products
      1. 2.3.1 UCC28056
      2. 2.3.2 LMG3622
      3. 2.3.3 LMG2610
  9. 3Hardware, Test Requirements, and Test Results
    1. 3.1 Hardware
    2. 3.2 Test Setup
    3. 3.3 Test Results
      1. 3.3.1 Switching Waveform
        1. 3.3.1.1 Switching Waveform on the PFC Stage
        2. 3.3.1.2 Switching Waveform on the AHB Stage
      2. 3.3.2 Efficiency Test Result
      3. 3.3.3 Thermal Test Result
  10. 4Design and Documentation Support
    1. 4.1 Design Files
      1. 4.1.1 Schematics
      2. 4.1.2 BOM
      3. 4.1.3 Layout Prints {Optional Section}
    2. 4.2 Tools
    3. 4.3 Documentation Support
    4. 4.4 Support Resources
    5. 4.5 Trademarks
  11. 5About the Author

3.3.1.2 Switching Waveform on the AHB Stage

For output voltage is 15V, 20V, and 28V, the PFC is always on and the bulk cap voltage is not related to the input voltage. The waveform of VDS and the transformer current was captured at full load based on different output voltage.

The channel setting for Figure 3-13 to Figure 3-22 is:

  • Ch1: SW (VDS of low side device) voltage
  • Ch4: The transformer current

The conditions for Figure 3-13 and Figure 3-14 are 28V–5A, 140W.

GUID-20231212-SS0I-9JNX-RNVC-JJVMPQJW2KP6-low.svg
The operation frequency is about 171.9kHz.
Figure 3-13 28V–5A AHB Switching Waveform (VPFC = 390V)
GUID-20231211-SS0I-SZZH-N2TB-SC0CRBFR8ZWL-low.svg
The operation frequency is about 147.8kHz.
Figure 3-14 28V–5A AHB Switching Waveform (VPFC = 320V)

The conditions for Figure 3-15 and Figure 3-16 are 20V–5A (100W).

GUID-20231212-SS0I-PBZK-FZRK-TKMSKLKB0KJP-low.svg
The operation frequency is about 157.8kHz.
Figure 3-15 20V–5A AHB Switching Waveform (VPFC = 390V)
GUID-20231212-SS0I-TFGD-BKRC-K8R7PNXZMCLG-low.svg
The operation frequency is about 146.9kHz.
Figure 3-16 20V–5A AHB Switching Waveform (VPFC = 320V)

The conditions for Figure 3-17 and Figure 3-18 are 15V–5A (75W).

GUID-20231211-SS0I-J8MW-CBRK-6SCKWBTWPR7Q-low.svg
The operation frequency is about 134.8kHz.
Figure 3-17 15V–5A AHB Switching Waveform (VPFC = 390V)
GUID-20231212-SS0I-XHP6-TNGM-HDMZVNKKZWNC-low.svg
The operation frequency is about 134.8kHz.
Figure 3-18 15V–5A AHB Switching Waveform (VPFC = 320V)

The conditions for Figure 3-19 and Figure 3-20 are 9V–3A (27W).

GUID-20231212-SS0I-ZRWN-MNGS-F6DHPNNCDP1X-low.svg
The operation frequency is about 74.1kHz.
Figure 3-19 9V–3A AHB Switching Waveform at 90Vac Input
GUID-20231211-SS0I-74L1-SZ7T-4TVQZZHK2XFT-low.svg
The operation frequency is about 99.57kHz.
Figure 3-20 9V–3A AHB Switching Waveform at 264Vac Input

The conditions for Figure 3-21 to Figure 3-22 are 5V–3A (15W).

GUID-20231211-SS0I-42G0-9XGS-GRKZQHJ5LBTM-low.svg
The operation frequency is about 62.3kHz.
Figure 3-21 5V–3A AHB Switching Waveform at 90Vac Input
GUID-20231212-SS0I-SB7H-H71C-M18LPRJRLLZP-low.svg
The operation frequency is about 66.52kHz.
Figure 3-22 5V–3A AHB Switching Waveform at 264Vac Input