参数资料
型号: LT1950EGN#TR
厂商: Linear Technology
文件页数: 15/20页
文件大小: 0K
描述: IC REG CTRLR PWM CM 16-SSOP
标准包装: 2,500
PWM 型: 电流模式
输出数: 1
频率 - 最大: 560kHz
占空比: 97%
电源电压: 3 V ~ 25 V
降压:
升压:
回扫:
反相:
倍增器:
除法器:
Cuk:
隔离:
工作温度: -40°C ~ 125°C
封装/外壳: 16-SSOP(0.154",3.90mm 宽)
包装: 带卷 (TR)
LT1950
APPLICATIO S I FOR ATIO
ability of the V SEC pin to follow input voltage and control
maximum switch duty cycle.
Forward Converter Applications
The LT1950 provides sophisticated control of the simplest
forward converter topology (single primary switch, see Q1
Figure 11). A significant problem in a single switch for-
ward converter topology is transformer reset. Optimum
transformer utilization requires maximum duty cycles.
Unfortunately as duty cycles increase the transformer
reset time decreases and reset voltages increase. This
increases the voltage requirements and stress on both
transformer and switch. The LT1950 incorporates an
adaptive maximum duty cycle clamp which controls maxi-
mum switch duty cycle based on system input voltage.
The adaptive clamp allows the converter to operate at up
to 75% duty cycle, allowing 25% of the switching period
for resetting the transformer. This results in greater
utilization of MOSFET, transformer and output rectifier
components. The V SEC pin can be programmed from
system input to adaptively control maximum duty cycle
(see Applications Information “Programming Volt-Sec-
ond Clamp” and the Maximum Duty Cycle vs V SEC Voltage
graph in the Typical Performance Characteristics section).
100
95
90
85
94% Efficient 3.3V, 20A Synchronous Forward
Converter
The synchronous forward converter in Figure 11 is based
on the LT1950 and uses MOSFETs as synchronous output
rectifiers to provide an efficient 3.3V, 20A isolated output
from 48V input. The output rectifiers are driven by the
LTC1698 which also serves as an error amplifier and
optocoupler driver. Efficiency and transient response
are shown in Figures 9 and 10. Peak efficiencies of 94%
and ultra-fast transient response are superior to presently
available power modules. In addition, the circuit in Figure 11
is an all-ceramic capacitor solution providing low output
ripple voltage and improved reliability. The LT1950-based
converter can be used to replace power module converters
at a much lower cost. The LT1950 solution benefits from
thermal conduction of the system board resulting in
higher efficiencies and lower rise in component tempera-
tures. The 7mm height allows dense packaging and the
circuit can be easily adjusted to provide an output voltage
from 1.23V to 15V. In addition, higher currents are achiev-
able by simple scaling of power components. The LT1950-
based solution in Figure 11 is a powerful topology for
replacement of a wide range of power modules.
LT1950
V OUT
(100mV/DIV)
POWER
MODULE
80
75
V IN = 48V
V OUT = 3.3V
f OSC = 235kHz
V OUT
(100mV/DIV)
70
0
5
10 15
20
500 μ s/DIV
1950 F10
LOAD CURRENT (A)
1950 F09
Figure 9. LT1950-Based Synchronous Forward
Converter Efficiency vs Load Current
Figure 10. Output Voltage Transient Response
to Load Steps (0A to 3.3A) LT1950 (Trace1)
vs Power Module (Trace 2)
1950fa
15
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LT1950IGN 功能描述:IC REG CTRLR PWM CM 16-SSOP RoHS:否 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)
LT1950IGN#PBF 功能描述:IC REG CTRLR PWM CM 16-SSOP 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:2,000 系列:- PWM 型:电流模式 输出数:1 频率 - 最大:1MHz 占空比:50% 电源电压:9 V ~ 10 V 降压:无 升压:是 回扫:是 反相:无 倍增器:无 除法器:无 Cuk:无 隔离:无 工作温度:-40°C ~ 85°C 封装/外壳:8-TSSOP(0.173",4.40mm 宽) 包装:带卷 (TR)
LT1950IGN#TR 功能描述:IC REG CTRLR PWM CM 16-SSOP RoHS:否 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)
LT1950IGN#TRPBF 功能描述:IC REG CTRLR PWM CM 16-SSOP 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)
LT1952 制造商:LINER 制造商全称:Linear Technology 功能描述:2-Phase Step-Up DC/DC Controller