参数资料
型号: LM3421Q0MHX/NOPB
厂商: National Semiconductor
文件页数: 43/67页
文件大小: 0K
描述: IC LED DRVR HP CONS CURR 16TSSOP
标准包装: 2,500
系列: PowerWise®
恒定电流:
拓扑: PWM,SEPIC,降压(降压),升压(升压)
输出数: 1
内部驱动器:
类型 - 主要: 车载
类型 - 次要: 高亮度 LED(HBLED)
频率: 2MHz
电源电压: 4.5 V ~ 75 V
输出电压: 3 V ~ 72 V
安装类型: 表面贴装
封装/外壳: 16-TSSOP(0.173",4.40mm)裸露焊盘
供应商设备封装: 16-TSSOP-EP
包装: 带卷 (TR)
工作温度: -40°C ~ 150°C
其它名称: LM3421Q0MHX
SNVS574E – JULY 2008 – REVISED MAY 2013
T U 0 =
D c x 620 V
( 1+ D ) x I LED x R LIM
=
0 . 533 x 620 V
1 . 467 x 1 A x 0 . 04 :
= 5630
(121)
To ensure stability, calculate ω P2 :
Z P1
Z P2 =
min( Z P1 , Z Z1 )
5 x T U0
=
rad
19 k
sec
=
5 x 5630 5 x 5630
= 0 . 675
rad
sec
(122)
Solve for C CMP :
Z P 2 x 5 e :
C CMP =
1
6
=
0 . 675
1
rad
sec
x 5 e 6 :
= 0 . 30 P F
(123)
To attenuate switching noise, calculate ω P3 :
Z P3 = (max Z P1 , Z Z1 ) x 10 = Z Z1 x 10
rad           rad
Z P3 = 36k sec x 10 = 360k sec
Assume R FS = 10 ? and solve for C FS :
(124)
C FS =
1
10 : x Z P 3
=
1
10 : x 360 k
rad
sec
= 0 . 28 P F
(125)
The chosen components from step 7 are:
C CMP = 0.33 P F
R FS = 10 :
C FS = 0 . 27 P F
8. INPUT CAPACITANCE
Solve for the minimum C IN :
(126)
C IN =
I LED x D
' v IN- PP x f SW
=
1 A x 0 . 467
100 mV x 504 kHz
= 9 . 27 P F
(127)
To minimize power supply interaction a 200% larger capacitance of approximately 20 μF is used, therefore the
actual Δ v IN-PP is much lower. Since high voltage ceramic capacitor selection is limited, four 4.7 μF X7R capacitors
are chosen.
Determine minimum allowable RMS current rating:
I IN- RMS = I LED x
D MAX
1- D MAX
= 1 A x
0 . 677
1- 0.677
= 1.45A
(128)
The chosen components from step 8 are:
C IN = 4 x 4.7 P F
9. NFET
Determine minimum Q1 voltage rating and current rating:
V T - MAX = V IN - MAX + V O = 70 V + 21 V = 91 V
(129)
(130)
Copyright ? 2008–2013, Texas Instruments Incorporated
43
Product Folder Links: LM3421 LM3421-Q1 LM3423 LM3423-Q1
相关PDF资料
PDF描述
RS-2405DZ/H2 CONV DC/DC 2W 9-36VIN +/-05VOUT
VI-B1W-CW-S CONVERTER MOD DC/DC 5.5V 100W
VI-B03-CX-S CONVERTER MOD DC/DC 24V 75W
ML03512R2BAT2A CAP MLO 2.2PF 50V 0603
LT3599IUH#PBF IC LED DRIVR WHITE BCKLGT 32-QFN
相关代理商/技术参数
参数描述
LM3421Q1 制造商:NSC 制造商全称:National Semiconductor 功能描述:N-Channel Controllers for Constant Current LED Drivers
LM3421Q1MH 制造商:NSC 制造商全称:National Semiconductor 功能描述:N-Channel Controllers for Constant Current LED Drivers
LM3421Q1MH/NOPB 功能描述:LED照明驱动器 RoHS:否 制造商:STMicroelectronics 输入电压:11.5 V to 23 V 工作频率: 最大电源电流:1.7 mA 输出电流: 最大工作温度: 安装风格:SMD/SMT 封装 / 箱体:SO-16N
LM3421Q1MHX 制造商:NSC 制造商全称:National Semiconductor 功能描述:N-Channel Controllers for Constant Current LED Drivers
LM3421Q1MHX/NOPB 功能描述:板上安装温度传感器 RoHS:否 制造商:Omron Electronics 输出类型:Digital 配置: 准确性:+/- 1.5 C, +/- 3 C 温度阈值: 数字输出 - 总线接口:2-Wire, I2C, SMBus 电源电压-最大:5.5 V 电源电压-最小:4.5 V 最大工作温度:+ 50 C 最小工作温度:0 C 关闭: 安装风格: 封装 / 箱体: 设备功能:Temperature and Humidity Sensor