参数资料
型号: LM2735XSDEVAL
厂商: National Semiconductor
文件页数: 13/58页
文件大小: 0K
描述: BOARD EVAL LM2735 1.6MHZ 6LLP
标准包装: 1
主要目的: DC/DC,步升
输出及类型: 1,非隔离
输出电压: 12V
电流 - 输出: 500mA
输入电压: 3 ~ 5.5 V
稳压器拓扑结构: 升压
频率 - 开关: 1.6MHz
板类型: 完全填充
已供物品:
已用 IC / 零件: LM2735
V FB
R 2
V O
C 3
R LOAD
SNVS485F – JUNE 2007 – REVISED APRIL 2013
R 1
Figure 22. Setting Vout
A good value for R1 is 10k ? .
R 2 = ¨ ¨
§ V OUT
? V REF
·
- 1 ? ? x R 1
1
(9)
COMPENSATION
The LM2735 uses constant frequency peak current mode control. This mode of control allows for a simple
external compensation scheme that can be optimized for each application. A complicated mathematical analysis
can be completed to fully explain the LM2735’s internal & external compensation, but for simplicity, a graphical
approach with simple equations will be used. Below is a Gain & Phase plot of a LM2735 that produces a 12V
output from a 5V input voltage. The Bode plot shows the total loop Gain & Phase without external compensation.
80
gm-Pole
180
60
RC-Pole
40
20
Vi = 5V
Vo = 12V
90
0
-20
-40
Io = 500 mA
Co = 10 P F
Lo = 5 P H
gm-Zero
0
-90
RHP-Zero
-60
-80
-180
10
100
1k
10k
100k
1M
FREQUENCY
Figure 23. LM2735 Without External Compensation
One can see that the Crossover frequency is fine, but the phase margin at 0dB is very low (22°). A zero can be
placed just above the crossover frequency so that the phase margin will be bumped up to a minimum of 45°.
Below is the same application with a zero added at 8 kHz.
Copyright ? 2007–2013, Texas Instruments Incorporated
Product Folder Links: LM2735
13
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PDF描述
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相关代理商/技术参数
参数描述
LM2735XSDEVAL 制造商:Texas Instruments 功能描述:EVAL BOARD, LM2735XSD, 500mA SEPIC CONVE
LM2735XSDX 制造商:NSC 制造商全称:National Semiconductor 功能描述:520kHz/1.6MHz - Space-Efficient Boost and SEPIC DC-DC Regulator
LM2735XSDX/NOPB 功能描述:直流/直流开关调节器 RoHS:否 制造商:International Rectifier 最大输入电压:21 V 开关频率:1.5 MHz 输出电压:0.5 V to 0.86 V 输出电流:4 A 输出端数量: 最大工作温度: 安装风格:SMD/SMT 封装 / 箱体:PQFN 4 x 5
LM2735YMF 功能描述:直流/直流开关调节器 RoHS:否 制造商:International Rectifier 最大输入电压:21 V 开关频率:1.5 MHz 输出电压:0.5 V to 0.86 V 输出电流:4 A 输出端数量: 最大工作温度: 安装风格:SMD/SMT 封装 / 箱体:PQFN 4 x 5
LM2735YMF/NOPB 功能描述:直流/直流开关调节器 SPACE-EFF BOOST AND SEPIC DC-DC REG RoHS:否 制造商:International Rectifier 最大输入电压:21 V 开关频率:1.5 MHz 输出电压:0.5 V to 0.86 V 输出电流:4 A 输出端数量: 最大工作温度: 安装风格:SMD/SMT 封装 / 箱体:PQFN 4 x 5