The backlight circuit usually features a dedicated step-up (boost) converter IC (such as the MP3394S or AP3608EM-G1). It takes the basic secondary +12V or +24V rail and boosts it up to the 30V–70V DC required by the specific LED strip array inside the panel.
Blown main fuse, shorted bridge rectifier, or shorted primary PWM/MOSFET chip.
The 12V secondary rail is fed through a boost inductor and switched by a dedicated LED driver IC and external MOSFET. This boosts the voltage up to the level required by the LED string (often between 30V and 70V DC, depending on panel size).
The primary controller switches a high-voltage MOSFET on and off at tens of kilohertz.
The is a widely used integrated power supply (PSU) and LED driver board found in numerous budget-friendly LED TVs from brands like Toshiba, JVC, Hitachi, and Philips. Understanding its schematic is essential for technicians dealing with common "no power" or "no backlight" symptoms. 1. Circuit Overview and Architecture 17ips72 schematic work
Manufacturers often push capacitors to their limits. If you're replacing them, consider slightly higher voltage ratings for better longevity.
Focus on the LED driver circuit. Measure the voltage across the backlight output connector during power-on. If the voltage spikes up high and then rapidly drops, the power supply is working fine, but one or more LEDs inside the panel screen are open-circuit. If there is no voltage spike at all, check the boost MOSFET, the boost inductor, or the driver IC VCC supply.
The transformer outputs lower AC voltages, which are then cleaned by Schottky diodes and capacitors. The board creates two primary voltage rails:
Absorbs over-voltage spikes from the mains supply. The backlight circuit usually features a dedicated step-up
As noted in this YouTube repair video , the soldering quality on some Vestel boards can be poor, leading to weak connections.
Pair the schematic with a (.BRD, .CAD, .FZ) to see physical component locations.
| 功能模块 | 常见芯片型号 | |---------|------------| | 待机PWM控制器 | ICE3BR1765J（Infineon）、MP150GJ、FSDM311 | | PFC控制器 | NCP1608、FAN7529、L6562 | | LLC主转换器 | NCP1392、ICE2HS01 | | LED背光驱动器 | OB3363QP、MP3394 | | 同步整流驱动器 | TEA1792 |
Typical tasks with the schematic:
Working on this common power board found in many budget LED TVs. These are notorious for "bad quality" PCBs and weak solder joints.
Failed LED driver circuit or open-circuit LED strips inside the panel.
该电源板搭载的主控芯片版本多样，其中常见芯片型号包括：
Either a single physical LED inside the panel array has burnt out open-circuit, or the boost converter MOSFET on the board has failed. The 12V secondary rail is fed through a
Before starting, download the specific revision for your board (e.g., R3 or R4), as component values can vary.