Ilpi354 Va Schematic Updated _hot_

This board serves as both the AC-to-DC power converter and the LED/LCD backlight driver (inverter). Common Applications:

The latest revision focuses on refining the VA stage. While the core topology remains familiar, several key changes have been implemented:

Replace capacitors C611, C612 (usually 10V or 16V 1000uF) on the secondary side, even if they look fine. Voltage Stability: Measure 12V and 5V under load. 3. Backlight Failure Check LED Connector: Ensure pins are not corroded.

: Delivers a stabilized 5V DC rail for the logic/scaler board logic gates and variable higher-voltage rails specialized for the W-LED backlight string . Architectural Functional Blocks

The board utilizes a PWM controller to maintain stable output voltages despite fluctuations in load or input.

Disclaimer: Always use an ESD mat and a current-limited power supply (1A max) when probing these circuits.

Main Fuse Blown, Shorted Bridge Rectifier, or Cracked PWM Controller IC.

Setting up a basic regulator requires only a few key components. The standard schematic revolves around a PI354x IC and six primary external parts.

| Ref Des | Function | Value | Notes | |---------|----------|-------|-------| | F101 | Primary fuse | 3.15A / 250V | Slow-blow | | IC901 | PWM controller | LD7535 (or compatible) | Pin 5 now correct | | QB801 | Backlight boost MOSFET | 60V / 3A | AO4404A | | R321, R322 | LED current sense | 2.2Ω, 1% (each) | Parallel | | R715 | ISET for LED driver | 100kΩ | Critical for brightness |

Test the forward voltage of the LED output line at startup using an external LED tester panel.

The secondary filtering stage outputting the 5V logic rail requires capacitors with strict low-ESR profiles. Replacing these with generic general-purpose capacitors will cause ripple current issues, leading to monitor flickering or system instability. Repair Safety Warnings

The ILPI-354 is a combined Switch Mode Power Supply (SMPS) and LED driver board. Its primary role is to convert AC mains voltage into the stable low-voltage DC lines required for the logic board and the LED backlight. Typically rated for 100-240V AC.