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參數(shù)資料
| 型號： | LT1508C |
| 廠商： | Linear Technology Corporation |
| 元件分類： | 基準(zhǔn)電壓源/電流源 |
| 英文描述： | Power Factor and PWM Controller(Voltage Mode) |
| 中文描述： | 功率因數(shù)和PWM控制器（電壓模式） |
| 文件頁數(shù)： | 8/16頁 |
| 文件大?。?/td> | 337K |
| 代理商： | LT1508C |
8
LT1508
APPLICATIO
S I
N
FOR
ATIO
U
W
U
To avoid subharmonic oscillations, the amplified downslope
of the inductor current must be less than the slope of the
oscillator ramp.
V
CA(OUT)
V
RS
(5V)(500
μ
H)(100k)
(382V)(0.15
)
(V
OSC
)(L)(f
SW
)
(V
OUT
)(R
S
)
≤
=
= 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:
V
RS
V
CA(OUT)
(382V)(0.15
)
(j)(2
π
f)(500
μ
H)(5V)
(V
OUT
)(R
S
)
(j)(2
π
f)(L)(V
OSC
)
3648
(j)(f)
=
=
=
The current error amp, with R5 = 4k, R6 = 20k, C3 =
0.001
μ
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.
V
IN
R
S
0.15
L
V
IN
I
IN
I
M
R
REF
4k
R5
4k
V
OUT
D1
C
OUT
470
μ
F
C4
300pF
C3
0.001
μ
F
R6
20k
I
SENSE
M
OUT
CA
OUT
–
+
CA
V
IN
R
IAC
1M
I
AC
1508 F02
LT1508
+
–
Figure 2
FREQUENCY (kHz)
0.1
–40
C
P
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
L
P
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/
μ
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 CA
OUT
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
I
M
= (I
AC
I
EA2
)/(200
μ
A
2
) with I
EA
= (VA
OUT
– 2V)/ 25k. The
error amplifier output voltage required at the input to the
multiplier is:
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| LT1508I | Power Factor and PWM Controller(Voltage Mode) |
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相關(guān)代理商/技術(shù)參數(shù) |
參數(shù)描述 |
|---|---|
| LT1508CN | 制造商:LINER 制造商全稱:Linear Technology 功能描述:Power Factor and PWM Controller(Voltage Mode) |
| LT1508CSW | 功能描述:IC PWM/POWER FACTOR CNTRLR20SOIC RoHS:否 類別:集成電路 (IC) >> PMIC - PFC（功率因數(shù)修正） 系列:- 產(chǎn)品培訓(xùn)模塊:GreenChip Synchronous Rectification Control Family of ICs 標(biāo)準(zhǔn)包裝:1 系列:- 模式:間歇導(dǎo)電（DCM） 頻率 - 開關(guān):- 電流 - 啟動:- 電源電壓:8.6 V ~ 38 V 工作溫度:-20°C ~ 150°C 安裝類型:表面貼裝 封裝/外殼:14-SOIC（0.154"，3.90mm 寬） 供應(yīng)商設(shè)備封裝:14-SO 包裝:Digi-Reel® 其它名稱:568-5348-6 |
| LT1508I | 制造商:LINER 制造商全稱:Linear Technology 功能描述:Power Factor and PWM Controller(Voltage Mode) |
| LT1508IN | 制造商:LINER 制造商全稱: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 類別:集成電路 (IC) >> PMIC - PFC（功率因數(shù)修正） 系列:- 產(chǎn)品培訓(xùn)模塊:GreenChip Synchronous Rectification Control Family of ICs 標(biāo)準(zhǔn)包裝:1 系列:- 模式:間歇導(dǎo)電（DCM） 頻率 - 開關(guān):- 電流 - 啟動:- 電源電壓:8.6 V ~ 38 V 工作溫度:-20°C ~ 150°C 安裝類型:表面貼裝 封裝/外殼:14-SOIC（0.154"，3.90mm 寬） 供應(yīng)商設(shè)備封裝:14-SO 包裝:Digi-Reel® 其它名稱:568-5348-6 |
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