- 您现在的位置：买卖IC网 > PDF目录15734 > LM3445TRIACEVAL (National Semiconductor)BOARD EVAL LM3445MM PDF资料下载
参数资料
| 型号： | LM3445TRIACEVAL |
| 厂商： | National Semiconductor |
| 文件页数： | 25/40页 |
| 文件大小： | 0K |
| 描述： | BOARD EVAL LM3445MM |
| 标准包装： | 1 |
| 系列： | PowerWise® |
| 电流 - 输出 / 通道： | 770mA |
| 输出及类型： | 1，非隔离 |
| 特点： | 可调光 |
| 输入电压： | 8 ~ 12V |
| 已供物品： | 板 |
| 已用 IC / 零件： | LM3445MM |
| 相关产品： | LM3445MMX-ND - IC LED DRIVER TRIAC DIMM 10-MSOP LM3445MMDKR-ND - IC LED DRIVER TRIAC DIMM 10-MSOP LM3445MMCT-ND - IC LED DRIVER TRIAC DIMM 10-MSOP LM3445MMTR-ND - IC LED DRIVER TRIAC DIMM 10-MSOP |
第1页第2页第3页第4页第5页第6页第7页第8页第9页第10页第11页第12页第13页第14页第15页第16页第17页第18页第19页第20页第21页第22页第23页第24页当前第25页第26页第27页第28页第29页第30页第31页第32页第33页第34页第35页第36页第37页第38页第39页第40页
SNVS570L – JANUARY 2009 – REVISED MAY 2013
45° 90° 135°
V PEAK
V AC
t
Figure 30. AC Line with Firing Angles
Figure 31 show three triac dimmed waveforms. One can easily see that the peak voltage (V PEAK ) from 0° to 90°
will always be:
V AC-RMS-PK 2
Once the triac is firing at an angle greater than 90° the peak voltage will lower and equal to:
V AC-RMS-PK 2 x SIN( T )
(27)
(28)
The voltage at V BUCK with a valley fill stage of two will look similar to the waveforms of Figure 32 .
The purpose of the valley fill circuit is to allow the buck converter to pull power directly off of the AC line when
the line voltage is greater than its peak voltage divided by two (two stage valley fill circuit). During this time, the
capacitors within the valley fill circuit (C7 and C8) are charged up to the peak of the AC line voltage. Once the
line drops below its peak divided by two, the two capacitors are placed in parallel and deliver power to the buck
converter. One can now see that if the peak of the AC line voltage is lowered due to variations in the line voltage,
or if the triac is firing at an angle above 90°, the DC offset (V DC ) will lower. V DC is the lowest value that voltage
V BUCK will encounter.
V BUCK(MIN) =
V AC-RMS(MIN) 2 x SIN( T )
#stages
(29)
Example:
Line voltage = 90V AC to 135V AC
Valley-Fill = two stage
90 2 x SIN(135 )
V BUCK(MIN) =
2
o
= 45V
(30)
Depending on what type and value of capacitors are used, some derating should be used for voltage droop when
the capacitors are delivering power to the buck converter. When the triac is firing at 135° the current through the
LED string will be small. Therefore the droop should be small at this point and a 5% voltage droop should be a
sufficient derating. With this derating, the lowest voltage the buck converter will see is about 42.5V in this
example.
Copyright ? 2009–2013, Texas Instruments Incorporated
Product Folder Links: LM3445
25
相关PDF资料 |
PDF描述 |
|---|---|
| VE-B00-EY-F1 | CONVERTER MOD DC/DC 5V 50W |
| ISC1812RXR39K | INDUCTOR WW 390NH 10% 1812 |
| HCM12DSEH | CONN EDGECARD 24POS .156 EYELET |
| MAX6441KADGWD7+T | IC BATTERY MON DUAL SOT23-8 |
| VE-B00-EX-S | CONVERTER MOD DC/DC 5V 75W |
相关代理商/技术参数 |
参数描述 |
|---|---|
| LM3445TRIACEVAL/NOPB | 制造商:Texas Instruments 功能描述:TRIAC Dimmable Offline LED Driver Evaluation Board |
| LM3447 | 制造商:TI 制造商全称:Texas Instruments 功能描述:Phase Dimmable, Primary Side Power Regulated PFC Flyback Controller for LED Lighting |
| LM3447-A19-120VEVM | 功能描述:LED 照明开发工具 LM3447 Eval Mod RoHS:否 制造商:Fairchild Semiconductor 产品:Evaluation Kits 用于:FL7732 核心: 电源电压:120V 系列: 封装: |
| LM3447-A19-230VEVM | 功能描述:LED 照明开发工具 LM3447 Eval Mod RoHS:否 制造商:Fairchild Semiconductor 产品:Evaluation Kits 用于:FL7732 核心: 电源电压:120V 系列: 封装: |
| LM3447MT | 制造商:TI 制造商全称:Texas Instruments 功能描述:a Phase-Dimmable, Primary-Side Regulated LED Driver |
发布紧急采购，3分钟左右您将得到回复。