收藏本站
LM3421, LM3421-Q1
LM3423, LM3423-Q1
SNVS574E – JULY 2008 – REVISED MAY 2013
www.ti.com
Z P 2 =
1
5 e 6 : x C CMP
(19)
It may also be necessary to add one final pole at least one decade above the crossover frequency to attenuate
switching noise and, in some cases, provide better gain margin. This pole can be placed across R SNS to filter the
ESL of the sense resistor at the same time. Figure 23 shows how the compensation is physically implemented in
the system.
The high frequency pole ( ω P3 ) can be calculated:
Z P 3 =
1
R FS x C FS
(20)
The total system transfer function becomes:
¨ 1 +
¨ 1 - s ?
Z Z 1 ? 1
? x ¨ 1 +
? x ¨ 1 +
Z P 1 ? Z P 2 ?
s ·
Z P 3 ?
T = T U 0 x
§
¨
?
s · § s · §
1 ? 1 ?
§ ·
¨
?
¨ ¨
?
1
(21)
The resulting compensated loop gain frequency response shown in Figure 24 indicates that the system has
adequate phase margin (above 45°) if the dominant compensation pole is placed low enough, ensuring stability:
80
60
? P2
90
45
40
GAIN
0
20
0
-20
-40
-60
-80
PHASE
60° Phase Margin
? Z1
? P1
? P3
-45
-90
-135
-180
-225
-270
1e-1
1e1
1e3
1e5
1e7
FREQUENCY (Hz)
Figure 24. Compensated Loop Gain Frequency Response
V CMP
0.9V
0
t VCC
t CMP
t CO
t
Figure 25. Start-Up Waveforms
18
Submit Documentation Feedback
Copyright ? 2008–2013, Texas Instruments Incorporated
Product Folder Links: LM3421 LM3421-Q1 LM3423 LM3423-Q1
发布紧急采购，3分钟左右您将得到回复。

采购需求

(若只采购一条型号，填写一行即可)

发布成功！您可以继续发布采购。也可以进入我的后台，查看报价

发布成功！您可以继续发布采购。也可以进入我的后台，查看报价

*型号 *数量 厂商 批号 封装
添加更多采购

我的联系方式

*
*
*
相关PDF资料
LM89EVAL BOARD EVALUATION LM89
LM95241EB BOARD EVALUATION LM95241
LOB3R005FLFLT RES METAL .005 OHM 3W 1% AXIAL
LP05-1A66-80V RELAY REED SPST 500MA 5V
LP5521TMEV EVAL BOARD FOR LP5521
LPS0300H1000JB RESISTOR HEAT SINK 100 OHM 300W
LPS0600H4R70JB RESISTOR HEAT SINK 4.7 OHM 600W
LPS0800H1000JB RESISTOR HEAT SINK 100 OHM 800W
相关代理商/技术参数
LM3423MHX 制造商:Rochester Electronics LLC 功能描述: 制造商:Texas Instruments 功能描述:
LM3423MHX/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
LM3423Q0 制造商:NSC 制造商全称:National Semiconductor 功能描述:N-Channel Controllers for Constant Current LED Drivers
LM3423Q0MH 制造商:NSC 制造商全称:National Semiconductor 功能描述:N-Channel Controllers for Constant Current LED Drivers
LM3423Q0MH/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
LM3423Q0MHX 制造商:NSC 制造商全称:National Semiconductor 功能描述:N-Channel Controllers for Constant Current LED Drivers
LM3423Q0MHX/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
LM3423Q1 制造商:NSC 制造商全称:National Semiconductor 功能描述:N-Channel Controllers for Constant Current LED Drivers