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参数资料
| 型号： | LM2577MX-12/NOPB |
| 厂商： | NATIONAL SEMICONDUCTOR CORP |
| 元件分类： | 稳压器 |
| 英文描述： | 6 A SWITCHING REGULATOR, 62 kHz SWITCHING FREQ-MAX, PDSO24 |
| 封装： | 0.300 INCH, SO-24 |
| 文件页数： | 11/34页 |
| 文件大小： | 1008K |
| 代理商： | LM2577MX-12/NOPB |
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Application Hints (Continued)
FLYBACK REGULATOR
A Flyback regulator can produce single or multiple output
voltages that are lower or greater than the input supply volt-
age.
Figure 18 shows the LM1577/LM2577 used as a fly-
back regulator with positive and negative regulated outputs.
Its operation is similar to a step-up regulator, except the out-
put switch contols the primary current of a flyback trans-
former. Note that the primary and secondary windings are
out of phase, so no current flows through secondary when
current flows through the primary. This allows the primary to
charge up the transformer core when the switch is on. When
the switch turns off, the core discharges by sending current
through the secondary, and this produces voltage at the out-
puts. The output voltages are controlled by adjusting the
peak primary current, as described in the step-up regulator
section.
Voltage and current waveforms for this circuit are shown in
Figure 17, and formulas for calculating them are given in Fig-
ure 19.
FLYBACK REGULATOR DESIGN PROCEDURE
1. Transformer Selection
A family of standardized flyback transformers is available for
creating flyback regulators that produce dual output volt-
ages, from ±10V to ±15V, as shown in
Figure 18. Figure
20lists these transformers with the input voltage, output volt-
ages and maximum load current they are designed for.
2. Compensation Network (C
C,RC) and
Output Capacitor (C
OUT) Selection
As explained in the Step-Up Regulator Design Procedure,
C
C,RC and COUT must be selected as a group. The following
procedure is for a dual output flyback regulator with equal
turns ratios for each secondary (i.e., both output voltages
have the same magnitude). The equations can be used for a
single output regulator by changing
∑I
LOAD(max) to ILOAD(max)
in the following equations.
A. First, calculate the maximum value for R
C.
Where
∑I
LOAD(max) is the sum of the load current (magni-
tude) required from both outputs. Select a resistor less than
or equal to this value, and no greater than 3 k
.
B. Calculate the minimum value for
∑C
OUT (sum of COUT
at both outputs) using the following two equations.
The larger of these two values must be used to ensure regu-
lator stability.
DS011468-17
FIGURE 17. Flyback Regulator Waveforms
DS011468-18
T1 = Pulse Engineering, PE-65300
D1, D2 = 1N5821
FIGURE 18. LM1577-ADJ/LM2577-ADJ Flyback Regulator with ± Outputs
www.national.com
19
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相关代理商/技术参数 |
参数描述 |
|---|---|
| LM2577MX-15 | 功能描述:IC REG MULTI CONFIG 15V 24SOIC RoHS:是 类别:集成电路 (IC) >> PMIC - 稳压器 - DC DC 开关稳压器 系列:SIMPLE SWITCHER® 产品培训模块:Lead (SnPb) Finish for COTS Obsolescence Mitigation Program 标准包装:1 系列:- 类型:降压（降压） 输出类型:固定 输出数:1 输出电压:3.3V 输入电压:4.5 V ~ 24 V PWM 型:- 频率 - 开关:- 电流 - 输出:125mA 同步整流器:无 工作温度:-40°C ~ 85°C 安装类型:表面贴装 封装/外壳:SOT-23-6 包装:Digi-Reel® 供应商设备封装:SOT-6 其它名称:MAX1836EUT33#TG16DKR |
| LM2577MX-ADJ | 功能描述:IC REG MULTI CONFIG ADJ 24SOIC RoHS:是 类别:集成电路 (IC) >> PMIC - 稳压器 - DC DC 开关稳压器 系列:SIMPLE SWITCHER® 产品培训模块:Lead (SnPb) Finish for COTS Obsolescence Mitigation Program 标准包装:1 系列:- 类型:降压（降压） 输出类型:固定 输出数:1 输出电压:3.3V 输入电压:4.5 V ~ 24 V PWM 型:- 频率 - 开关:- 电流 - 输出:125mA 同步整流器:无 工作温度:-40°C ~ 85°C 安装类型:表面贴装 封装/外壳:SOT-23-6 包装:Digi-Reel® 供应商设备封装:SOT-6 其它名称:MAX1836EUT33#TG16DKR |
| LM2577N-12 | 制造商:Rochester Electronics LLC 功能描述: 制造商:Texas Instruments 功能描述: |
| LM2577N-12/NOPB | 功能描述:IC REG MULTI CONFIG 12V 3A 16DIP RoHS:是 类别:集成电路 (IC) >> PMIC - 稳压器 - DC DC 开关稳压器 系列:SIMPLE SWITCHER® 产品培训模块:Lead (SnPb) Finish for COTS Obsolescence Mitigation Program 标准包装:1 系列:- 类型:降压（降压） 输出类型:固定 输出数:1 输出电压:3.3V 输入电压:4.5 V ~ 24 V PWM 型:- 频率 - 开关:- 电流 - 输出:125mA 同步整流器:无 工作温度:-40°C ~ 85°C 安装类型:表面贴装 封装/外壳:SOT-23-6 包装:Digi-Reel® 供应商设备封装:SOT-6 其它名称:MAX1836EUT33#TG16DKR |
| LM2577N-15 | 制造商:NSC 制造商全称:National Semiconductor 功能描述:SIMPLE SWITCHER-R Step-Up Voltage Regulator |
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