• State Resolved
  • Locked Locked
  • Replies 1 reply
  • Subscribers 63 subscribers
  • Views 408 views
  • Users 0 members are here
Support feedback
Options
Options
Related

This thread has been locked.

If you have a related question, please click the "Ask a related question" button in the top right corner. The newly created question will be automatically linked to this question.

LM51561-Q1: When configure in boot circuit, what will happen if Vin > Vout ?

PYTsai
Genius 11665 points
Part Number: LM51561-Q1
Other Parts Discussed in Thread: LM51561

Hi 

Below is our circuit, the the target output is Vout = 21.1V, 0.15A. 

if we apply 26V to the input of this circuit from connector P1, what voltage will we see at VREG (Vout) ? 

And will this damage the LM51561? 

  • +1
    TI__Guru 58641 points

    Hi,

    if the voltage rises above the output voltage level adjusted by the regulator feedback resistor divider, the output voltage will follow the input voltage (minus the voltage drop above the components in-between (Diode D2 / D3 and Inductor L1/L2)

    If the voltage goes above the V OVTH the LM51561 stops switching - see also Datasheet: 9.3.14 Overvoltage Protection (OVP)

    For your circuit this should be at a voltage level of  ~ 23.9V (21.1 + 13%)

    Note: you wrote device is configured in Boot Circuit. I assume you meant Boost Circuit.

    The device will not be damaged (when BIAS and VCC are separated as shown in your schematic) 

    ~ Stefan