The backlight inverter circuit typically consists of a high voltage transformer, a set of MOSFETs, and a control chip that generates the PWM signal to control the brightness of the backlight. The control chip is usually a dedicated IC that is specifically designed for this purpose.
The name and part number of the control chip can vary depending on the specific laptop model, but it is typically located near the high voltage transformer and the MOSFETs on the motherboard. You can try searching for the service manual or schematic diagram for your laptop model, which should provide more detailed information on the location and part number of the control chip.
In terms of the PWM input, this is typically controlled by the laptop's display driver or graphics card. The PWM signal is sent to the control chip, which then adjusts the brightness of the backlight by varying the output voltage to the high voltage transformer.
I hope this information helps, but please note that working with high voltage electronics can be dangerous and should only be attempted by experienced technicians. If you are not familiar with the proper safety procedures and techniques, it is best to seek professional help or guidance.
