- 您现在的位置：买卖IC网 > PDF目录15304 > LT3825EFE#TRPBF (Linear Technology)IC REG CTRLR FLYBK ISO 16-TSSOP PDF资料下载
参数资料
| 型号： | LT3825EFE#TRPBF |
| 厂商： | Linear Technology |
| 文件页数： | 15/32页 |
| 文件大小： | 0K |
| 描述： | IC REG CTRLR FLYBK ISO 16-TSSOP |
| 标准包装： | 2,500 |
| PWM 型： | 电流模式 |
| 输出数： | 1 |
| 频率 - 最大： | 250kHz |
| 占空比： | 88% |
| 电源电压： | 11 V ~ 18 V |
| 降压： | 无 |
| 升压： | 无 |
| 回扫： | 是 |
| 反相： | 无 |
| 倍增器： | 无 |
| 除法器： | 无 |
| Cuk： | 无 |
| 隔离： | 是 |
| 工作温度： | -40°C ~ 125°C |
| 封装/外壳： | 16-TSSOP（0.173"，4.40mm）裸露焊盘 |
| 包装： | 带卷 (TR) |
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页当前第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页第25页第26页第27页第28页第29页第30页第31页第32页
LT3825
APPLICATIONS INFORMATION
DC MIN =
=
= 35.7%
1 +
N ? V IN(MAX) 1 72
V OUT
P IN
? ? 1 + MIN ?
I PK =
DC MAX =
=
= 52.6%
1 +
N ? V IN(MIN) 1 36
V OUT
( V IN(MIN) ? DC MAX )
( )
36 ? 52.6%
( 72V ? 0.357 )
L P = = 186 μ H
? = 2.58A
I PK =
? ? 1 +
Ripplecurrentandpercentagerippleislargestatminimum
duty cycle; in other words, at the highest input voltage.
L P is calculated from:
L P = ( V IN(MAX) ? DC MIN ) 2 = ( V IN(MAX) ? DC MIN ) 2 ? Eff
f OSC ? X MAX ? P IN f OSC ? X MAX ? P OUT
where:
f OSC is the oscillator frequency
DC MIN is the DC at maximum input voltage
X MAX is ripple current ratio at maximum input voltage
For a 48V (V IN = 36V to 72V) to 5V/8A converter with 90%
efficiency, P OUT = 40W and P IN = 44.44W. Using X = 0.4
and f OSC = 200kHz:
1 1
1 + ?
8 5
2
200kHz ? 0.4 ? 44.44W
Optimization might show that a more efficient solution
is obtained at higher peak current but lower inductance
and the associated winding series resistance. A simple
spreadsheet program is useful for looking at trade-offs.
Transformer Core Selection
Once L P is known, the type of transformer is selected.
High efficiency converters use ferrite cores to minimize
core loss. Actual core loss is independent of core size for
a fixed inductance, but decreases as inductance increases.
Since increased inductance is accomplished through more
turns of wire, copper losses increase. Thus transformer
design balances core and copper losses. Remember that
increased winding resistance will degrade cross regulation
and increase the amount of load compensation required.
The main design goals for core selection are reducing
copper losses and preventing saturation. Ferrite core
material saturates hard, rapidly reducing inductance
when the peak design current is exceeded. This results
in an abrupt increase in inductor ripple current and, con-
sequently, output voltage ripple. Do not allow the core
to saturate! The maximum peak primary current occurs
at minimum V IN :
? X ?
V IN(MIN) ? DC MAX ? 2 ?
now :
1 1
1 + ?
8 5
2 2
X MIN = =
f OSC ? L P ? P IN 200kHz ? 186 μ H ? 44.44
= 0.202
Using the example numbers leads to:
44.44W ? 0.202 ?
36 ? 0.526 ? 2 ?
Multiple Outputs
One advantage that the flyback topology offers is that ad-
ditional output voltages can be obtained simply by adding
windings. Designing a transformer for such a situation is
beyond the scope of this document. For multiple windings,
realize that the flyback winding signal is a combination of
activity on all the secondary windings. Thus load regulation
is affected by each windings load. Take care to minimize
cross regulation effects.
3825fe
15
相关PDF资料 |
PDF描述 |
|---|---|
| VE-J2X-EY-F2 | CONVERTER MOD DC/DC 5.2V 50W |
| IMC1210EBR10J | INDUCTOR WW 100NH 5% 1210 |
| PCF1D820MCL1GS | CAP ALUM 82UF 20V 20% SMD |
| AS1902-C23-T | IC SUPERVISOR ACT HIGH SOT23-3 |
| LT3837EFE#TRPBF | IC REG CTRLR FLYBK ISO 16-TSSOP |
相关代理商/技术参数 |
参数描述 |
|---|---|
| LT382B | 制造商:EDSYN 功能描述:TIP CONICAL 0.5X15.8MM |
| LT383 | 制造商:EDSYN 功能描述: |
| LT3837 | 制造商:LINER 制造商全称:Linear Technology 功能描述:Low VIN, 8A DC/DC μModule Regulator |
| LT3837EFE | 制造商:Linear Technology 功能描述:Current Mode PWM Controller 16-Pin TSSOP EP |
| LT3837EFE#PBF | 功能描述:IC REG CTRLR FLYBK ISO 16-TSSOP RoHS:是 类别:集成电路 (IC) >> PMIC - 稳压器 - DC DC 切换控制器 系列:- 特色产品:LM3753/54 Scalable 2-Phase Synchronous Buck Controllers 标准包装:1 系列:PowerWise® PWM 型:电压模式 输出数:1 频率 - 最大:1MHz 占空比:81% 电源电压:4.5 V ~ 18 V 降压:是 升压:无 回扫:无 反相:无 倍增器:无 除法器:无 Cuk:无 隔离:无 工作温度:-5°C ~ 125°C 封装/外壳:32-WFQFN 裸露焊盘 包装:Digi-Reel® 产品目录页面:1303 (CN2011-ZH PDF) 其它名称:LM3754SQDKR |
发布紧急采购，3分钟左右您将得到回复。