TIDUF26 june   2023 BQ24072 , LMR36520 , TLV62568 , TPS2116

 

  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 24 VAC to DC Rectification
      2. 2.2.2 eFuse Protection
      3. 2.2.3 5-V Rails
        1. 2.2.3.1 LMR36520 Voltage Rail
        2. 2.2.3.2 USB Power Input
      4. 2.2.4 Power Source ORing
      5. 2.2.5 Battery Management
      6. 2.2.6 3.3-V Power Rail
      7. 2.2.7 Power Rail Current Sensing
      8. 2.2.8 Backlight LED Driver
      9. 2.2.9 BoosterPack Overview
    3. 2.3 Highlighted Products
      1. 2.3.1 LMR36520
      2. 2.3.2 TPS2116
      3. 2.3.3 TLV62568
      4. 2.3.4 INA2180
      5. 2.3.5 TPS92360
      6. 2.3.6 TPS2640
      7. 2.3.7 BQ24072
  9. 3Hardware, Software, Testing Requirements, and Test Results
    1. 3.1 Hardware Requirements
    2. 3.2 Test Setup
    3. 3.3 Test Results
      1. 3.3.1  24-VAC Start-Up and Shutdown
      2. 3.3.2  USB Start-Up and Shutdown
      3. 3.3.3  ORing
      4. 3.3.4  LMR36520
      5. 3.3.5  TLV62568 Transient Response
      6. 3.3.6  BM24072 Transient Response
      7. 3.3.7  TLV62568 (3V3 Power Rail)
      8. 3.3.8  LMR36520 (LMOut Power Rail)
      9. 3.3.9  BM24072 (BMOut Power Rail)
      10. 3.3.10 Reference
        1. 3.3.10.1 TLV62568
        2. 3.3.10.2 LMR36520
  10. 4Design and Documentation Support
    1. 4.1 Design Files
      1. 4.1.1 Schematics
      2. 4.1.2 BOM
    2. 4.2 Tools and Software
    3. 4.3 Documentation Support
    4. 4.4 Support Resources
    5. 4.5 Trademarks
  11. 5About the Author

3.3.7 TLV62568 (3V3 Power Rail)

Perhaps the most important power rail to monitor the ripple and noise is the TLV62568 3V3 because it is powering the system load. In this reference design, the TLV62568 exhibits very low amplitude ripple. At a 125-mA load test, shown in Figure 3-33, the ripple of the 3V3 rail is equal or less than the noise floor of the oscilloscope used for testing. Figure 3-34 shows low jitter on the switch node when using only one source. When using two sources during high current loads as shown in Figure 3-38, the battery in addition to the PWRin source, the SW node exhibits more jitter because the input voltage is constantly changing to balance battery and PWRin sources. Even while using dual sources and full load current the ripple of the 3V3 rail stays beneath 0.75%.

GUID-20230607-SS0I-34QX-MRF5-VHTSZCRMNBHC-low.png Figure 3-30 3V3 Ripple (No Load; 24-VAC Source)
GUID-20230607-SS0I-MHH1-XX97-3JGQTT75QFQD-low.png Figure 3-31 3V3 Ripple (90-mA; 24-VAC Source)
GUID-20230607-SS0I-CQNW-GK2R-JK6C1XS651LK-low.png Figure 3-32 3V3 Ripple (125-mA; 24-VAC Source)
GUID-20230607-SS0I-ZZDF-X0VR-WXR48RQZGPBG-low.png Figure 3-33 3V3 Ripple (210-mA; 24-VAC Source)
GUID-20230607-SS0I-WLPS-G1BS-GQ0VVJHBBQTB-low.png Figure 3-34 3V3 Ripple Persist (210-mA; 24-VAC Source)
GUID-20230607-SS0I-8TR5-W83T-7PLKFGF44CBM-low.png Figure 3-35 3V3 Ripple (90-mA Load; 24-VAC Source Plus Battery)
GUID-20230607-SS0I-1JB7-LLJB-70JNQDDSKZLQ-low.png Figure 3-36 3V3 Ripple (125-mA Load; 24-VAC Source Plus Battery)
GUID-20230607-SS0I-VWMG-6XBM-9XQBK3DSKPLH-low.png Figure 3-37 3V3 Ripple (210-mA Load; 24-VAC Source Plus Battery)
GUID-20230607-SS0I-GTNJ-X8LK-SXKBKPXXSK0H-low.png Figure 3-38 3V3 Ripple Persist (210-mA Load; 24-VAC Source Plus Battery)
GUID-20230607-SS0I-GTNJ-X8LK-SXKBKPXXSK0H-low.png Figure 3-39 3V3 Ripple Persist (1-A Load; 24-VAC Source Plus Battery)
GUID-20230607-SS0I-MDMS-H30S-TZXQNKPBNJCL-low.png Figure 3-40 3V3 Ripple Persist (1-A Load; Battery Only)