SLYT872 November   2025 LM74700D-Q1

 

  1.   1
  2. 12
  3. 2Challenge 1: High voltage stress during reverse supply fault
  4. 3Challenge 2: Compliance to LV148 load dump and switching transients
  5. 4Single controller-based solution
  6. 5Proposed cascaded ideal diode configuration
  7. 6Component selection and test results
  8. 7Conclusion
  9. 8References

4 Single controller-based solution

Figure 5 shows a solution using a single LM74700D-Q1, but using a Zener clamp circuit reduces the large voltage difference of 108V between the CATHODE to ANODE pins of the controller. The Zener diode DZ can limit the voltage between CATHODE to ANODE below its absolute max rating (75V) and the resistor RZ can bias DZ appropriately. However, the solution still requires at least 120V rated MOSFETs which are comparatively expensive than 60V FETs and are hard to multi-source. Also, in normal operation the resistor RZ causes additional drop in the CATHODE path, which impacts the reverse current protection threshold.

Solution with single high voltage MOSFET Figure 5 Solution with single high voltage MOSFET