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TINA/Spice/LM5122: LM5122 After UVLO set to 0V, Vout remains at 12V.

Part Number: LM5122
Other Parts Discussed in Thread: TINA-TI, , TIDA-00699

Tool/software: TINA-TI or Spice Models

Dear all,

I am working on a boost circuit to provide an output that behaves as follow:

Vin = 4.5V - 12V --> Vout = 12V

Vin > 12V --> Vout = Vin

I need to shut down the device and I tried to do this pulling the UVLO signal to 0V in a TINA simulation. What happens is that Vout remains at 12V and current continues to flow in the load (in the schematic it is a constant power load, but I also tried with a simple resistor). I cannot understand why this happens. How can I deactivate the HMOS? Wouldn't it be automatically done when UVLO=0V? Or am I misunderstanding the use of the LM5122?

(I took inspiration from TIDA-00699)

In this simulation the Vin remains stable at 12V. At 5ms I switch ON T1 so that UVLO voltage drops to 0V.

Has anybody suggestions?

Thank you very much,

Leo