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参数资料
| 型号： | IRU3048CFTR |
| 厂商： | International Rectifier |
| 文件页数： | 8/18页 |
| 文件大小： | 0K |
| 描述： | IC REG CTRLR BUCK PWM VM 16TSSOP |
| 标准包装： | 1 |
| PWM 型： | 电压模式 |
| 输出数： | 3 |
| 频率 - 最大： | 220kHz |
| 占空比： | 90% |
| 电源电压： | 4.2 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： | 16-TSSOP（0.173"，4.40mm 宽） |
| 包装： | 剪切带 (CT) |
| 产品目录页面： | 1384 (CN2011-ZH PDF) |
| 其它名称： | *IRU3048CFTR IRU3048CFCT |
IRU3048
Feedback Compensation
The IRU3048 is a voltage mode controller; the control
V OUT
loop is a single voltage feedback path including error
R 6
F b
amplifier and error comparator. To achieve fast transient
response and accurate output regulation, a compensa-
tion circuit is necessary. The goal of the compensation
network is to provide a closed loop transfer function with
the highest 0dB crossing frequency and adequate phase
R 8
V REF
E/A
Comp
Ve
C 18
R 9
margin (greater than 45 8 ).
The output LC filter introduces a double pole, –40dB/
decade gain slope above its corner resonant frequency,
and a total phase lag of 180 8 (see Figure 5). The Reso-
Gain(dB)
H(s) dB
nant frequency of the LC filter is expressed as follows:
F Z
Frequency
F LC =
2 p
1
Lo 3 Co
---(7)
Figure 6 - Compensation network without local
feedback and its asymptotic gain plot.
Figure 5 shows gain and phase of the LC filter. Since we
The transfer function (Ve / V OUT ) is given by:
(
)
3
already have 180 8 phase shift just from the output filter,
the system risks being unstable.
H(s) = g m 3
R 8
R 6 + R 8
1 + sR 9 C 18
sC 18
---(9)
Gain
Phase
0dB
-40dB/decade
0 8
The (s) indicates that the transfer function varies as a
function of frequency. This configuration introduces a gain
and zero, expressed by:
|H(s)| = g m 3
R 8
R 6 3 R 8
3 R 9
---(10)
F LC Frequency
-180 8
F LC
Frequency
F Z =
1
2 p 3 R 9 3 C 18
---(11)
Figure 5 - Gain and phase of LC filter.
The gain is determined by the voltage divider and E/A's
The IRU3048's error amplifier is a differential-input
transconductance amplifier. The output is available for
DC gain control or AC phase compensation.
The E/A can be compensated with or without the use of
local feedback. When operated without local feedback
transconductance gain.
First select the desired zero-crossover frequency (Fo):
F O1 > F ESR and F O1 [ (1/5 ~ 1/10) 3 f S
Use the following equation to calculate R4:
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
R 9 =
V OSC
V IN1
3
F O1 3 F ESR1
F LC12
3
R 8 + R 6
R 8
3
1
g m
---(12)
from Comp1 pin to ground as shown in Figure 6.
The ESR zero of the LC filter expressed as follows:
Where:
V IN1 = Maximum Input Voltage
V OSC = Oscillator Ramp Voltage
F ESR =
1
2 p 3 ESR 3 Co
---(8)
F O1 = Crossover Frequency for the master E/A
F ESR1 = Zero Frequency of the Output Capacitor
F LC1 = Resonant Frequency of Output Filter
g m = Error Amplifier Transconductance
R 8 and R 6 = Resistor Dividers for Output Voltage
Programming
8
www.irf.com
Rev. 1.7
09/12/02
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相关代理商/技术参数 |
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|---|---|
| IRU3048CS | 制造商:IRF 制造商全称:International Rectifier 功能描述:DUAL SYNCHRONOUS PWM CONTROLLER CIRCUITRY AND LDO CONTROLLER |
| IRU3048CSTR | 功能描述:IC REG CTRLR BUCK PWM VM 16-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:75 系列:- PWM 型:电流模式 输出数:1 频率 - 最大:1MHz 占空比:81% 电源电压:4.3 V ~ 13.5 V 降压:是 升压:是 回扫:是 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:管件 产品目录页面:1051 (CN2011-ZH PDF) 其它名称:296-2543-5 |
| IRU3048CSTRPBF | 制造商:International Rectifier 功能描述:Dual Synchronous PWM Controller Circuitry and LDO Controller 16-Pin SOIC N T/R |
| IRU3055 | 制造商:IRF 制造商全称:International Rectifier 功能描述:5-BIT PROGRAMMABLE 3-PHASE SYNCHRONOUS BUCK CONTROLLER IC |
| IRU3055CQ | 制造商:IRF 制造商全称:International Rectifier 功能描述:5-BIT PROGRAMMABLE 3-PHASE SYNCHRONOUS BUCK CONTROLLER IC |
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