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| 型号： | IRU3047CWTR |
| 厂商： | International Rectifier |
| 文件页数： | 7/19页 |
| 文件大小： | 0K |
| 描述： | IC REG CTRLR BUCK PWM VM 20-SOIC |
| 标准包装： | 1 |
| PWM 型： | 电压模式 |
| 输出数： | 2 |
| 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： | 20-SOIC（0.295"，7.50mm 宽） |
| 包装： | 剪切带 (CT) |
| 产品目录页面： | 1384 (CN2011-ZH PDF) |
| 其它名称： | *IRU3047CWTR IRU3047CWCT |
IRU3047
For higher efficiency, a low ESR capacitor is recom-
mended.
For the buck converter, the inductor value for desired
operating ripple current can be determined using the fol-
lowing relation:
For V I N 1 =12V, choose two Poscap from Sanyo
16TPB47M (16V, 47 m F, 70m V , 1.4A)
V IN - V OUT = L 3
D i
D t
; D t = D 3
1
f S
;D=
V OUT
V IN
For V IN2 =5V, choose two 6TPB330M (6.3V, 330 m F,
L = (V IN - V OUT ) 3
V OUT
V IN 3D i 3 f S
---(6)
40m V , 3A).
Output Capacitor Selection
The criteria to select the output capacitor is normally
based on the value of the Effective Series Resistance
(ESR). In general, the output capacitor must have low
enough ESR to meet output ripple and load transient
requirements, yet have high enough ESR to satisfy sta-
bility requirements. The ESR of the output capacitor is
calculated by the following relationship:
Where:
V IN = Maximum Input Voltage
V OUT = Output Voltage
? i = Inductor Ripple Current
f S = Switching Frequency
? t = Turn On Time
D = Duty Cycle
For D i 1 =30% of I 1 , we get L 3 =5.46 m H
For D i 2 =30% of I 2 , we get: L 4 =3.47 m H
ESR [
D V O
D I O
---(5)
The Coilcraft DO5022HC series provides a range of in-
ductors in different values and low profile for large cur-
Where:
D V O = Output Voltage Ripple
D I O = Output Current
rents.
For L 3 choose DO5022P-602HC (6 m H, 7.5A)
For L 4 choose DO5022P-472HC (4.7 m H, 8.4A)
D V O =100mV and D I O =5A, results to ESR=20m V
Power MOSFET Selection
The Sanyo TPC series, PosCap capacitor is a good
choice. The 6TPB470M 470 m F, 6.3V has an ESR 40m V .
Selecting two of these capacitors in parallel, results to
an ESR of ? 20m V which achieves our low ESR goal.
The capacitor value must be high enough to absorb the
inductor's ripple current. The larger the value of capaci-
The selections criteria to meet power transfer require-
ments is based on maximum drain-source voltage (V DSS ),
gate-source drive voltage (V GS ), maximum output cur-
rent, On-resistance R DS(ON) and thermal management.
The MOSFET must have a maximum operating voltage
(V DSS ) exceeding the maximum input voltage (V IN ).
tor, the lower will be the output ripple voltage.
The gate drive requirement is almost the same for both
The resulting output ripple current is smaller then each
channel ripple current due to the 180 8 phase shift. These
currents cancel each other. The cancellation is not the
maximum because of the different duty cycle for each
channel.
Inductor Selection
The inductor is selected based on output power, operat-
ing frequency and efficiency requirements. Low induc-
tor value causes large ripple current, resulting in the
smaller size, but poor efficiency and high output noise.
Generally, the selection of inductor value can be reduced
to desired maximum ripple current in the inductor ( ? i);
the optimum point is usually found between 20% and
50% ripple of the output current.
MOSFETs. Caution should be taken with devices at very
low V GS to prevent undesired turn-on of the complemen-
tary MOSFET, which results a shoot-through current.
The total power dissipation for MOSFETs includes con-
duction and switching losses. For the Buck converter
the average inductor current is equal to the DC load cur-
rent. The conduction loss is defined as:
2
P COND (Upper Switch) = I LOAD 3 R DS(ON) 3 D 3q
2
P COND (Lower Switch) = I LOAD 3 R DS(ON) 3 (1 - D) 3q
q = R DS(ON) Temperature Dependency
The total conduction loss is defined as:
P CON(TOTAL) =P CON (Upper Switch) q +P CON (Lower Switch) q
Rev. 1.0
09/09/02
www.irf.com
7
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相关代理商/技术参数 |
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|---|---|
| IRU3048 | 制造商:IRF 制造商全称:International Rectifier 功能描述:DUAL SYNCHRONOUS PWM CONTROLLER CIRCUITRY AND LDO CONTROLLER |
| IRU3048CF | 制造商:IRF 制造商全称:International Rectifier 功能描述:DUAL SYNCHRONOUS PWM CONTROLLER CIRCUITRY AND LDO CONTROLLER |
| IRU3048CFTR | 功能描述:IC REG CTRLR BUCK PWM VM 16TSSOP 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 |
| 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 |
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