PowerInt公司的LYTSwitch-0系列产品是专门用来驱动低成本LED灯和T8管灯的IC,集成了700V功率MOSFET,振荡器,ON/OFF控制方案,EMI降低电路和控制功能包括限流和热关断等.本文介绍了LYTSwitch-0系列产品主要特性, 12 W LED T8管灯电源解决方案主要特性和指标,电路图,材料清单和PCB布局图.
The LYTSwitch-0 family is specifically designed for low cost LED bulb and T8 tube applications. LYTSwitch-0 devices monolithically integrate a 700 V power MOSFET, oscillator, ON/OFF controller scheme, EMI reduction and control functions including cycle-by-cycle current limit and thermal shutdown circuitry into one IC.

LYTSwitch-0系列产品主要特性:
Cost-Effective
The LYTSwitch-0 family enables low component-count, non-isolated switching topologies for highly cost competitive LED lighting applications.
66 kHz operation together with frequency jittering insures a very low EMI filter cost.
Start-up and operating power are derived directly from the voltage on the DRAIN pin, eliminating the need for a bias supply and associated circuitry.
Power Factor Correction
The LYTSwitch-0 family enables designs that easily meet European and North American standards for PFC in consumer lighting applications.
Tight CC Performance
Accurate CC with tight line and load regulation that is stable over a wide temperature range makes the LYTSwitch-0 ideal for LED lighting applications.
Comprehensive Protection
Integrated auto-restart for short-circuit, open-circuit and open loop faults as well as a hysteretic over temperature protection feature (135 °C) provide extensive protection at no additional　cost.Supports Different LED Applications
Buck, buck-boost non-isolated flyback, and boost architectures are all supported by the LYTSwitch-0 family. The 700 V switching power MOSFET supports an input voltage range of 85 VAC to 308 VAC.Package options for thru-hole and surface-mount suit different manufacturing requirements.

12 W LED T8管灯电源解决方案
This document describes a cost effective power supply utilizing the LYTSwitchTM-0 family (LYT0006D) in a highly compact buck topology.
This power supply operates over an input voltage range of 190 VAC to 265 VAC. The DC　bus voltage is high enough to support 85 V output when using a buck topology. In a buck　converter the output voltage must always be lower than the input voltage.
The output　voltage is also limited by the maximum duty cycle of the LYTSwitch-0, which also　requires the input voltage to be larger than the output voltage.
The reference design is not limited for LED tube of ballast lamp application; due to its　simplicity the design layout can be easily modified for retrofit lamp applications.

12 W LED T8管灯电源主要特性:
 Combined single-stage high power factor (>0.7 at 230 VAC) with accurate constant current(CC) output
 Low cost, low component count and small PCB footprint solution
 Highly energy efficient, >90% across input
 Fast start-up time (<100 ms) – no perceptible delay
 Integrated protection and reliability features
 Single shot no-load protection
 Output short-circuit protection with auto-recovery
 Auto-recovering hysteretic thermal shutdown protects both components and PCB
 No damage during brown-out
 Meets IEC ring wave, differential line surge and EN55015 conducted EMI


图1. 12 W LED T8管灯电源外形图

12 W LED T8管灯电源主要指标:



图2.12 W LED T8管灯电源电路图


图3.12 W LED T8管灯电源PCB布局图
12 W LED T8管灯电源材料清单: