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参数资料
| 型号： | LT1508CS |
| 厂商： | LINEAR TECHNOLOGY CORP |
| 元件分类： | 稳压器 |
| 英文描述： | 1.5 A POWER FACTOR CONTROLLER, 300 kHz SWITCHING FREQ-MAX, PDSO20 |
| 封装： | PLASTIC, SO-20 |
| 文件页数： | 15/16页 |
| 文件大小： | 232K |
| 代理商： | LT1508CS |
8
LT1508
APPLICATIONS INFORMATION
WU
U
To avoid subharmonic oscillations, the amplified downslope
of the inductor current must be less than the slope of the
oscillator ramp.
VCA(OUT)
VRS
(VOSC)(L)(fSW)
(VOUT)(RS)
(5V)(500
H)(100k)
(382V)(0.15
)
≤
=
= 4.4
If the current amplifier gain at 100kHz is less than 4.4,
there will be no subharmonic oscillation. The open-loop
gain of the current loop is given by:
VRS
VCA(OUT)
(VOUT)(RS)
(j)(2
πf)(L)(VOSC)
3648
(j)(f)
(382V)(0.15
)
(j)(2
πf)(500H)(5V)
=
==
The current error amp, with R5 = 4k, R6 = 20k, C3 =
0.001
F and C4 = 300pF, provides zero pole compensa-
tion resulting in 16kHz loop crossover frequency. The
current amp gain at 100kHz is 1.7. The resulting current
loop gain and phase margin is shown in Figure 4.
VIN
RS
0.15
L
VIN
IIN
IM
RREF
4k
R5
4k
VOUT
D1
COUT
470
F
C4
300pF
C3
0.001
F
R6
20k
ISENSE
MOUT
CAOUT
–
+
CA
VIN
RIAC
1M
IAC
1508 F02
LT1508
+
–
Figure 2
FREQUENCY (kHz)
0.1
–40
CURRENT
LOOP
GAIN
(dB)
PHASE
MARGIN
(DEG)
40
60
80
1
10
100
1000
1508 F04
20
0
–20
–30
30
45
60
15
0
–15
Figure 4
FREQUENCY (Hz)
0.1
–40
LOOP
GAIN
(dB)
PHASE
MARGIN
(DEG)
40
60
80
1
10
100
1000
1508 F03
20
0
–20
–30
30
45
60
15
0
–15
Figure 3
Current Amplifier (PFC Section)
The current amplifier has a 110dB DC gain, 3MHz unity-
gain frequency and a 2V/
s slew rate. It is internally
clamped at 8.5V. Note that in the current averaging opera-
tion, high gain at twice the line frequency is necessary to
minimize line current distortion. Because CAOUT may need
to swing 5V over one line cycle at high line condition,
20mV AC will be needed at the inputs of the current
amplifier for a gain of 260 at 120Hz. Especially at light load
when the current loop reference signal is small, lower gain
will distort the reference signal and line current. But, if
signal gain at switching frequency is too high, the system
behaves more like a current mode system and can cause
subharmonic oscillation.
Multiplier
The multiplier has high noise immunity and superior
linearity over its full operating range. The current gain is
IM = (IACIEA2)/(200A2) with IEA = (VAOUT – 2V)/ 25k. The
error amplifier output voltage required at the input to the
multiplier is:
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| LT1621IGN#TR | SPECIALTY ANALOG CIRCUIT, PDSO16 |
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相关代理商/技术参数 |
参数描述 |
|---|---|
| LT1508CSW | 功能描述:IC PWM/POWER FACTOR CNTRLR20SOIC RoHS:否 类别:集成电路 (IC) >> PMIC - PFC（功率因数修正） 系列:- 产品培训模块:GreenChip Synchronous Rectification Control Family of ICs 标准包装:1 系列:- 模式:间歇导电（DCM） 频率 - 开关:- 电流 - 启动:- 电源电压:8.6 V ~ 38 V 工作温度:-20°C ~ 150°C 安装类型:表面贴装 封装/外壳:14-SOIC（0.154"，3.90mm 宽） 供应商设备封装:14-SO 包装:Digi-Reel® 其它名称:568-5348-6 |
| LT1508I | 制造商:LINER 制造商全称:Linear Technology 功能描述:Power Factor and PWM Controller(Voltage Mode) |
| LT1508IN | 制造商:LINER 制造商全称:Linear Technology 功能描述:Power Factor and PWM Controller(Voltage Mode) |
| LT1508ISW | 功能描述:IC PWM/POWER FACTOR CNTRLR20SOIC RoHS:否 类别:集成电路 (IC) >> PMIC - PFC（功率因数修正） 系列:- 产品培训模块:GreenChip Synchronous Rectification Control Family of ICs 标准包装:1 系列:- 模式:间歇导电（DCM） 频率 - 开关:- 电流 - 启动:- 电源电压:8.6 V ~ 38 V 工作温度:-20°C ~ 150°C 安装类型:表面贴装 封装/外壳:14-SOIC（0.154"，3.90mm 宽） 供应商设备封装:14-SO 包装:Digi-Reel® 其它名称:568-5348-6 |
| LT1509 | 制造商:LINER 制造商全称:Linear Technology 功能描述:Power Factor and PWM Controller |
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