SNOAAA8 April   2025 LM74610-Q1

 

  1.   1
  2.   Abstract
  3.   Trademarks
  4. 1Introduction
    1. 1.1 What is MLPE
    2. 1.2 Why, When, Where Needs MLPE
    3. 1.3 What is Solar Power Optimizer
    4. 1.4 Solar Power Optimizer Working Principle
    5. 1.5 Output Bypass Function of Solar Power Optimizer
  5. 2Traditional Designs of the Bypass Circuit
    1. 2.1 Design 1 - Using P-N Junction Diode or Schottky Diode
    2. 2.2 Design 2 - Using MOSFET
  6. 3New Design of the Bypass Circuit
    1. 3.1 Requirements on Bypass Circuit
    2. 3.2 Using Ideal Diode Controller LM746x0-Q1
    3. 3.3 Challenges of Using Ideal Diode Controller
    4. 3.4 Working Principle of LM746x0-Q1 Reverse Voltage Range Extension
  7. 4Bench Test and Result
  8. 5Summary
  9. 6References

2.2 Design 2 - Using MOSFET

To overcome high power loss disadvantages of the diode design, as shown in Figure 2-2, using MOSFET which has much lower voltage drop or power loss (because of low Rdson) is an alternative. However, there still are some drawbacks,

  • MOSFET is not a standalone design, the ON or OFF needs MCU control.
  • MCU control needs power from PV panel, if PV panel is badly damaged or fully covered by shadow, then MCU is not able to work then MOSFET cannot be correctly turned ON.
  • In cases that MCU does not work or is out of control, the MOSFET is not turned ON, now the bypass path is the parasitic diode. But parasitic diode cannot bear large current and can accumulate huge amounts of heat that finally has risk of causing fire.
MOSFET Design of Bypass Circuit Figure 2-2 MOSFET Design of Bypass Circuit