Backlight circuit document in Spanish, a 741 KB PDF that likely explains or diagrams a display backlight driver stage. The name gives no device, brand or board number, so it may be a generic explanation rather than a model-specific schematic. Backlight drivers are usually boost converters with an inductor, diode, filter capacitors and an enable and PWM signal from the processor. Useful when a screen shows an image only under a torch; check the fuse, coil, diode and output voltage, and compare with the real schematic of the phone under repair.
The button opens the matching file on RM Schematics, or a source page if it is not catalogued there yet. The original attachment is from @canalesquematicos. Enginerys does not host this file.
How to open a .pdf file
The standard format for schematics, block diagrams, power-sequence charts and service manuals.