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参数资料
| 型号： | IRU3137CSTRPBF |
| 厂商： | International Rectifier |
| 文件页数： | 10/19页 |
| 文件大小： | 0K |
| 描述： | IC REG CTRLR BUCK PWM VM 8-SOIC |
| 标准包装： | 2,500 |
| PWM 型： | 电压模式 |
| 输出数： | 1 |
| 频率 - 最大： | 240kHz |
| 占空比： | 90% |
| 电源电压： | 4.25 V ~ 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： | 0°C ~ 70°C |
| 封装/外壳： | 8-SOIC（0.154"，3.90mm 宽） |
| 包装： | 带卷 (TR) |
IRU3137
The IRU3137’s error amplifier is a differential-input
transconductance amplifier. The output is available for
DC gain control or AC phase compensation.
First select the desired zero-crossover frequency (Fo):
Fo > F ESR and F O ≤ (1/5 ~ 1/10) × f S
Use the following equation to calculate R 4 :
Fo × F ESR
× × g m
R 4 = ×
The E/A can be compensated with or without the use of
local feedback. When operated without local feedback,
the transconductance properties of the E/A become evi-
dent and can be used to cancel one of the output filter
poles. This will be accomplished with a series RC circuit
from Comp pin to ground as shown in Figure 9.
V IN F LC2 R 5
Where:
V IN = Maximum Input Voltage
V OSC = Oscillator Ramp Voltage
Fo = Crossover Frequency
V OSC R 5 + R 6 1
---(18)
Note that this method requires that the output capacitor
should have enough ESR to satisfy stability requirements.
In general, the output capacitor’s ESR generates a zero
typically at 5KHz to 50KHz which is essential for an
acceptable phase margin.
F ESR = Zero Frequency of the Output Capacitor
F LC = Resonant Frequency of the Output Filter
R 5 and R 6 = Resistor Dividers for Output Voltage
Programming
g m = Error Amplifier Transconductance
For:
The ESR zero of the output capacitor expressed as fol-
lows:
1
F ESR = ---(14)
2 π× ESR × Co
V OUT
V IN = 5V
V OSC = 2.5V
Fo = 20KHz
F ESR = 12KHz
This results to R 4 =26.7K
F LC = 3.43KHz
R 5 = 1K
R 6 = 2.15K
g m = 600 μ mho
R 6
Fb
Choose R 4 =30K
R 5
Vp=V REF
E/A
Comp
C 9
Ve
To cancel one of the LC filter poles, place the zero be-
fore the LC filter resonant frequency pole:
F Z ? 75%F LC
Gain(dB)
R 4
Optional
F Z ? 0.75 ×
2 π
1
L O × C O
---(19)
For:
H(s) dB
Lo = 2.17 μ H
Co = 990 μ F
F Z = 2.57KHz
R 4 = 20K
F Z
(
)
H(s) = g m ×
×
C 9 × C POLE
Frequency
Figure 9 - Compensation network without local
feedback and its asymptotic gain plot.
The transfer function (Ve / V OUT ) is given by:
R 5 1 + sR 4 C 9
---(15)
R 6 + R 5 sC 9
The (s) indicates that the transfer function varies as a
function of frequency. This configuration introduces a gain
and zero, expressed by:
Using equations (17) and (19) to calculate C 9 , we get:
C 9 ? 2006pF; Choose C 9 =3300pF
One more capacitor is sometimes added in parallel with
C 9 and R 4 . This introduces one more pole which is mainly
used to suppress the switching noise. The additional
pole is given by:
1
F P =
2 π× R 4 ×
C 9 + C POLE
The pole sets to one half of switching frequency which
|H(s=j × 2 π× F O )| = g m ×
× R 4
F Z =
---(17)
?
π× R 4 × f S
π× R 4 × f S -
R 5
R 6 × R 5
1
2 π× R 4 × C 9
|H(s)| is the gain at zero cross frequency.
www.irf.com
---(16)
results in the capacitor C POLE:
1 1
C POLE =
1
C 9
For F P << f S /2
R 4 =30K and F S =200KHz will result to C POLE =53pF.
Choose C POLE =47pF.
10
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相关代理商/技术参数 |
参数描述 |
|---|---|
| IRU3138 | 制造商:IRF 制造商全称:International Rectifier 功能描述:SYNCHRONOUS PWM CONTROLLER FOR TERMINATION POWER SUPPLY APPLICATIONS |
| IRU3138CS | 制造商:IRF 制造商全称:International Rectifier 功能描述:SYNCHRONOUS PWM CONTROLLER FOR TERMINATION POWER SUPPLY APPLICATIONS |
| IRU3138CSTR | 功能描述:IC REG CTRLR BUCK PWM VM 14-SOIC 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: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) |
| IRU3138CSTRPBF | 功能描述:电压模式 PWM 控制器 SYNC PWM CTRLLER 1A .8V 200 to 400kHz RoHS:否 制造商:Texas Instruments 输出端数量:1 拓扑结构:Buck 输出电压:34 V 输出电流: 开关频率: 工作电源电压:4.5 V to 5.5 V 电源电流:600 uA 最大工作温度:+ 125 C 最小工作温度:- 40 C 封装 / 箱体:WSON-8 封装:Reel |
| IRU3146 | 制造商:IRF 制造商全称:International Rectifier 功能描述:DUAL SYNCHRONOUS PWM CONTROLLER WITH CURRENT SHARING CIRCUITRY AND AUTO-RESTART |
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