SNVAA19 May   2021 LP8863-Q1 , LP8864-Q1 , LP8864S-Q1 , LP8866-Q1 , LP8866S-Q1

 

  1.   Trademarks
  2. 1Introduction
  3. 2Boost Output Voltage Range Design Consideration
  4. 3Boost UVP Design Consideration
  5. 4Boost OVP Design Consideration
  6. 5Calculation of Feedback Resistor Values
  7. 6Feedback Resistor Calculation Example
  8. 7References

4 Boost OVP Design Consideration

When the voltage of DISCHARGE pin is higher than VBOOST_OVPH (typically 50 V, minimum 48.5 V for LP8866-Q1), boost OVP high fault will be reported and device will go to fault recovery until boost voltage falls below threshold before restarting, as shown in Table 3-1. Be careful when designing boost OVP low threshold of initial voltage considering the overshoot during start-up. The boost OVP low threshold of initial voltage should be designed to be triggered first before DISCHARGE pin reaching VBOOST_OVPH. Otherwise, boost OVP high fault will be reported if DISCHARGE pin reaches 48.5 V during start-up. Then the device will go to fault recovery mode and restart again and again. Therefore, we recommend to design VBOOST_OVP_LOW_INITIAL < 48 V, as shown in Equation 4.

Equation 4. GUID-20210423-CA0I-H27F-LFSB-KRKNGGVS5Z7D-low.gif

Where:

  • VBOOST_OVP_LOW_INITIAL is the boost OVP Llow threshold for initial voltage during start up
  • 48 V is 0.5 V (additional margin) below the minimum VBOOST_OVPH.