参数资料
型号: MC34262P
厂商: ON Semiconductor
文件页数: 6/19页
文件大小: 394K
描述: IC CTRLR PFC PRECONVERTER 8-DIP
产品变化通告: LTB Notification 03/Jan/2008
标准包装: 50
模式: 临界传导(CRM)
电流 - 启动: 250µA
电源电压: 12 V ~ 28 V
工作温度: 0°C ~ 85°C
安装类型: 通孔
封装/外壳: 8-DIP(0.300",7.62mm)
供应商设备封装: 8-PDIP
包装: 管件
MC34262, MC33262
http://onsemi.com
6
0
10
20
30
40
V
CC
, SUPPLY VOLTAGE (V)
V
FB
 = 0 V
Current Sense = 0 V
Multiplier = 0 V
C
L
 = 1.0 nF
f = 50 kHz
T
A
 = 25癈
-55
-25
0
25
50
75
100
125
T
A
, AMBIENT TEMPERATURE (癈)
Figure 14. Supply Current
versus Supply Voltage
Figure 15. Undervoltage Lockout Thresholds
versus Temperature
Startup Threshold
(V
CC
 Increasing)
16
12
8.0
4.0
0
14
13
12
11
9.0
7.0
8.0
10
Minimum Operating Threshold
(V
CC
 Decreasing)
FUNCTIONAL DESCRIPTION
Introduction
With the goal of exceeding the requirements of
legislation on linecurrent harmonic content, there is an
ever increasing demand for an economical method of
obtaining a unity power factor. This data sheet describes a
monolithic control IC that was specifically designed for
power factor control with minimal external components. It
offers the designer a simple, costeffective solution to
obtain the benefits of active power factor correction.
Most electronic ballasts and switching power supplies
use a bridge rectifier and a bulk storage capacitor to derive
raw dc voltage from the utility ac line, Figure 16.
Figure 16. Uncorrected Power Factor Circuit
AC
Line
Rectifiers
Converter
Bulk
Storage
Capacitor
+
Load
This simple rectifying circuit draws power from the line
when the instantaneous ac voltage exceeds the capacitor
voltage. This occurs near the line voltage peak and results
in a high charge current spike, Figure 17. Since power is
only taken near the line voltage peaks, the resulting spikes
of current are extremely nonsinusoidal with a high content
of harmonics. This results in a poor power factor condition
where the apparent input power is much higher than the real
power. Power factor ratios of 0.5 to 0.7 are common.
Power factor correction can be achieved with the use of
either a passive or an active input circuit. Passive circuits
usually contain a combination of large   capacitors,
inductors, and rectifiers that operate at the ac line
frequency. Active circuits incorporate some form of a high
frequency switching converter for the power processing,
with the boost converter being the most popular topology,
Figure 18. Since active input circuits operate at a frequency
much higher than that of the ac line, they are smaller,
lighter in weight, and more efficient than a passive circuit
that yields similar results. With proper control of the
preconverter, almost any complex load can be made to
appear resistive to the ac line, thus significantly reducing
the harmonic current content.
Figure 17. Uncorrected Power Factor
Input Waveforms
V
pk
Rectified
0
AC Line
Voltage
0
AC Line
Current
Line Sag
DC
The MC34262, MC33262 are high performance, critical
conduction,   currentmode   power   factor   controllers
specifically   designed   for   use   in   offline   active
preconverters. These devices provide the necessary
features required to significantly enhance poor power
factor loads by keeping the ac line current sinusoidal and
in phase with the line voltage.
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MC34262PG 功能描述:功率因数校正 IC Critical Mode PFC w/OVP RoHS:否 制造商:Fairchild Semiconductor 开关频率:300 KHz 最大功率耗散: 最大工作温度:+ 125 C 安装风格:SMD/SMT 封装 / 箱体:SOIC-8 封装:Reel
MC34262PG 制造商:ON Semiconductor 功能描述:Power Supply IC
MC34268D 功能描述:低压差稳压器 - LDO 2.85V 800mA SCSI-2 RoHS:否 制造商:Texas Instruments 最大输入电压:36 V 输出电压:1.4 V to 20.5 V 回动电压(最大值):307 mV 输出电流:1 A 负载调节:0.3 % 输出端数量: 输出类型:Fixed 最大工作温度:+ 125 C 安装风格:SMD/SMT 封装 / 箱体:VQFN-20
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MC34268DR2 功能描述:低压差稳压器 - LDO 2.85V 800mA SCSI-4 RoHS:否 制造商:Texas Instruments 最大输入电压:36 V 输出电压:1.4 V to 20.5 V 回动电压(最大值):307 mV 输出电流:1 A 负载调节:0.3 % 输出端数量: 输出类型:Fixed 最大工作温度:+ 125 C 安装风格:SMD/SMT 封装 / 箱体:VQFN-20