- 您现在的位置：买卖IC网 > PDF目录15304 > LT3837EFE#TRPBF (Linear Technology)IC REG CTRLR FLYBK ISO 16-TSSOP PDF资料下载
参数资料
| 型号： | LT3837EFE#TRPBF |
| 厂商： | Linear Technology |
| 文件页数： | 13/28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： | 4.5 V ~ 20 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页当前第13页第14页第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
LT3837
APPLICATIONS INFORMATION
V OUT + I OUT ? ( ESR + R DS(ON) )
V FLYBK =
( )
R2 ? V OUT + I OUT ? ESR + R DS(ON)
V FB ? N SP ?
R SENSE ? ( 1–DC )
ESR + R DS(ON)
N IDEAL = OUT ?
N IDEAL =
=
?
PrimaryWindingFeedback
The previous work was developed using a separate wind-
ing for voltage feedback. It is possible to use the primary
winding as the feedback winding as well. This can simplify
the design of the transformer.
When using the primary winding the feedback voltage
will be added to the V IN voltage so:
N SP
where N SP is the transformer effective secondary to
primary winding turns ratio. Use the circuit of Figure 2
to get more accurate output regulation. In this case the
regulation equations becomes:
?
R1 = ? ? ? V BE ?
? ?
where V BE is the base emitter drop of the PNP (approxi-
mately 0.7V).
Likewise the load compensation equation needs to be
changed to use N SP instead of N SF so:
R CMP = K1 ? ? R1 ? N SF
Transformer Design
Transformer design/specification is the most critical part
of a successful application of the LT3837. The following
sections provide basic information about designing the
transformer and potential tradeoffs.
If you need help, the LTC Applications group is available to
assist in the choice and/or design of the transformer.
Turns Ratios
The design of the transformer starts with determining
duty cycle (DC). DC impacts the current and voltage stress
on the power switches, input and output capacitor RMS
currents and transformer utilization (size vs power).
The ideal turns ratio is:
V 1–DC
V IN DC
Avoid extreme duty cycles as they, in general, increase
current stresses. A reasonable target for duty cycle is
50% at nominal input voltage.
For instance, if we wanted a 9V to 3.3V converter at 50%
DC then:
3.3 1– 0.5 1
9 0.5 2.72
In general, better performance is obtained with a lower
turns ratio. A DC of 52% yields a 1:3 ratio.
R1
R2
V FLYBK
LT3837
FB
PG
V IN
PRIMARY
MP
?
?
SECONDARY
MS
C OUT
Note the use of the external feedback resistive divider
ratio to set output voltage provides the user additional
freedom in selecting a suitable transformer turns ratio.
Turns ratios that are the simple ratios of small integers;
e.g., 1:1, 2:1, 3:2 help facilitate transformer construction
and improve performance.
When building a supply with multiple outputs derived
through a multiple winding transformer, lower duty cycle
can improve cross regulation by keeping the synchronous
rectifier on longer, and thus, keep secondary windings
coupled longer.
3837 F02
Figure 2
For a multiple output transformer, the turns ratio between
output windings is critical and affects the accuracy of the
voltages. The ratio between two output voltages is set with
the formula V OUT2 = V OUT1 ? N21 where N21 is the turns
3837fd
13
相关PDF资料 |
PDF描述 |
|---|---|
| GBM43DCBS | CONN EDGECARD 86POS R/A .156 SLD |
| UVY1E102MPD | CAP ALUM 1000UF 25V 20% RADIAL |
| VE-J2X-EY-F1 | CONVERTER MOD DC/DC 5.2V 50W |
| LTC1735CF#TR | IC REG CTRLR BUCK PWM CM 20TSSOP |
| IMC1210EB82NJ | INDUCTOR WW 82NH 5% 1210 |
相关代理商/技术参数 |
参数描述 |
|---|---|
| LT3837IFE#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:- 标准包装:2,500 系列:- PWM 型:电流模式 输出数:1 频率 - 最大:500kHz 占空比:96% 电源电压:4 V ~ 36 V 降压:无 升压:是 回扫:无 反相:无 倍增器:无 除法器:无 Cuk:无 隔离:无 工作温度:-40°C ~ 125°C 封装/外壳:24-WQFN 裸露焊盘 包装:带卷 (TR) |
| LT3837IFE#TRPBF | 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:- 标准包装:2,500 系列:- PWM 型:电流模式 输出数:1 频率 - 最大:500kHz 占空比:96% 电源电压:4 V ~ 36 V 降压:无 升压:是 回扫:无 反相:无 倍增器:无 除法器:无 Cuk:无 隔离:无 工作温度:-40°C ~ 125°C 封装/外壳:24-WQFN 裸露焊盘 包装:带卷 (TR) |
| LT383L313 | 制造商:未知厂家 制造商全称:未知厂家 功能描述:Optoelectronic |
| LT3844 | 制造商:LINER 制造商全称:Linear Technology 功能描述:High Voltage, Current Mode Switching Regulator Controller with Programmable Operating Frequency |
| LT3844EFE | 制造商:LINER 制造商全称:Linear Technology 功能描述:High Voltage, Current Mode Switching Regulator Controller with Programmable Operating Frequency |
发布紧急采购，3分钟左右您将得到回复。