- 您现在的位置：买卖IC网 > PDF目录45007 > LX1571CDM-TR (MICROSEMI CORP-ANALOG MIXED SIGNAL GROUP) 1 A SWITCHING CONTROLLER, PDSO8 PDF资料下载
参数资料
| 型号： | LX1571CDM-TR |
| 厂商： | MICROSEMI CORP-ANALOG MIXED SIGNAL GROUP |
| 元件分类： | 稳压器 |
| 英文描述： | 1 A SWITCHING CONTROLLER, PDSO8 |
| 封装： | LEAD FREE, PLASTIC, SOIC-8 |
| 文件页数： | 2/12页 |
| 文件大小： | 293K |
| 代理商： | LX1571CDM-TR |
PHASE MODULATED AC SYNCHRONOUS SECONDARY-SIDE CONTROLLER
LX1570/1571
PRODUCT DA T ABOOK 1996/1997
Copyright 1997
Rev. 0.9.3a 9/15/2004
10
P RELIMINAR Y D AT A S HEET
MINIMUM CURRENT COMPARATOR
One of the main advantages of replacing a Magnetic Amplifier
with a MOSFET, is the MOSFET's ability to respond quickly to
large changes in load requirements. Because the LX1570/71 re-
lies on the C.S. signal for synchronization, special circuitry had to
be added to keep the output drive synchronized to the trans-
former voltage during such load transient conditions. This con-
dition is best explained by referring to Figure 7. In Figure 7, it
can be seen that the load current is stepped from 0.4A to 4A,
causing the COMP pin to slew faster than the inductor current,
starting with the second switching cycle after the load transient
has occured. This condition eliminates the normal means of
resetting the PWM latch through the C.S. comparator path. To
compensate for this condition, a second comparator is ORed
with the C.S. comparator, which resets the latch on the falling
edge of the C.S. signal caused by the falling edge of the trans-
former voltage.
In other words, the function of the minimum C.S. comparator
is to turn OUT DRV off on the falling edge of the C.S. signal, if it
is not already off. This assures that the output drive is on before
the start of the next AC input cycle (Look-Ahead Switching),
allowing maximum converter duty cycle.
ERROR AMPLIFIER
The function of the error amplifier is to set a threshold voltage
for inductor peak current and to control the converter duty cycle,
such that power supply output voltage is closely regulated.
Regulation is done by sensing the output voltage and comparing
it to the internal 2.5V reference. A compensation network based
on the application is placed from the output of the amplifier to
GND for closed loop stability purposes as well as providing high
DC gain for tight regulation. The function of "3V
BE" offset is to
keep output drive off without requiring the error amplifier output
to swing to ground level. The transfer function between error
amp output (V
COMP) and peak inductor current is therefore given
by:
V
COMP - 3VBE = IP * G
where:
I
P
= inductor peak current,
G = resistor divider gain,
(-15 for LX1570, 3 for LX1571)
V
BE = diode forward voltage
(0.65V typ)
IC DESCRIPTION
FIGURE 7 — MINIMUM CURRENT COMPARATOR EFFECT
DURING LOAD TRANSIENT
Transformer
Voltage
100V / Div.
LX157x
OUT DRV
20V / Div.
LX157x
COMP PIN
2V / Div.
Output Current &
Inductor Current
2A / Div.
相关PDF资料 |
PDF描述 |
|---|---|
| LX1571IDM-TR | 1 A SWITCHING CONTROLLER, PDSO8 |
| LX1570IDMT | 1 A SWITCHING CONTROLLER, 100 kHz SWITCHING FREQ-MAX, PDSO8 |
| LX1571MY | 1 A SWITCHING CONTROLLER, 100 kHz SWITCHING FREQ-MAX, CDIP8 |
| LX1571CM | 1 A SWITCHING CONTROLLER, 100 kHz SWITCHING FREQ-MAX, PDIP8 |
| LX1571IDM | 1 A SWITCHING CONTROLLER, 100 kHz SWITCHING FREQ-MAX, PDSO8 |
相关代理商/技术参数 |
参数描述 |
|---|---|
| LX1571CM | 功能描述:IC REG CTRLR ISO PWM CM 8-DIP 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:4,000 系列:- PWM 型:电压模式 输出数:1 频率 - 最大:1.5MHz 占空比:66.7% 电源电压:4.75 V ~ 5.25 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:-40°C ~ 85°C 封装/外壳:40-VFQFN 裸露焊盘 包装:带卷 (TR) |
| LX1571IDM | 功能描述:IC REG CTRLR ISO PWM CM 8-SOIC 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:4,000 系列:- PWM 型:电压模式 输出数:1 频率 - 最大:1.5MHz 占空比:66.7% 电源电压:4.75 V ~ 5.25 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:-40°C ~ 85°C 封装/外壳:40-VFQFN 裸露焊盘 包装:带卷 (TR) |
| LX1571IM | 功能描述:IC REG CTRLR ISO PWM CM 8-DIP 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:4,000 系列:- PWM 型:电压模式 输出数:1 频率 - 最大:1.5MHz 占空比:66.7% 电源电压:4.75 V ~ 5.25 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:-40°C ~ 85°C 封装/外壳:40-VFQFN 裸露焊盘 包装:带卷 (TR) |
| LX1571MY | 功能描述:IC REG CTRLR ISO PWM CM 8-DIP 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:4,000 系列:- PWM 型:电压模式 输出数:1 频率 - 最大:1.5MHz 占空比:66.7% 电源电压:4.75 V ~ 5.25 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:-40°C ~ 85°C 封装/外壳:40-VFQFN 裸露焊盘 包装:带卷 (TR) |
| LX15RQ-75884 | 制造商:Banner Engineering 功能描述:LX15RQ-75884 LO Output |
发布紧急采购，3分钟左右您将得到回复。