Please identify this 6-pin SMD marked AI531
The package marking probably is: "A1" followed by "531" in a different font (like image shown below where the code is A1-287).  

  

Image source: https://www.aliexpress.com/item/32810968329.html

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It likely is the RT9284A from Richtek.


  The RT9284A/B is a compact, high efficient and high integration LED driver. Internal 22V MOSFET can support 2 to 5 White LEDs for backlighting and camera flashing.