參數(shù)資料
型號: IRU3055
廠商: International Rectifier
英文描述: 5-BIT PROGRAMMABLE 3-PHASE SYNCHRONOUS BUCK CONTROLLER IC
中文描述: 5位可編程3相位同步降壓控制器IC
文件頁數(shù): 13/26頁
文件大?。?/td> 352K
代理商: IRU3055
IRU3055
13
Rev. 1.4
08/13/02
www.irf.com
Input Filter Selection
Figure 12 - Normalized input RMS current vs.
duty cycle.
The selection criteria of input capacitor are voltage rat-
ing and the RMS current rating. For conservative consid-
eration, the capacitor voltage rating should be 1.5 times
higher than the maximum input voltage. The RMS cur-
rent rating of the input capacitor for multi-phase con-
verter can be estimated from the above Figure 12.
First, determine the duty cycle of the converter (V
O
/V
IN
).
The ratio of input RMS current over output current can
be obtained. Then the total input RMS current can be
calculated. From this figure, it is obvious that a multi-
phase converter can have a much smaller input RMS
current, which results in a lower amount of input capaci-
tors that are required.
For high current applications, multiple bulk input capaci-
tors in parallel may be necessary. Some electrolytic
capacitors, such as Panasonic HFQ series, Sanyo MV-
WX or equivalent may be put in parallel to provide a large
current. In addition, ceramic bypass capacitors for high
frequency de-coupling are recommended. Furthermore,
some small ceramic capacitors should be put very close
to the drain of the high side MOSFET and source of the
low side switch to suppress the voltage spike caused by
parasitic circuit parameters.
For high current applications, a 1
μ
H input inductor is
recommended to slow down the input current transient.
0
0.1
0.2
0.3
0.4
0.5
0
0.1
0.2
0.3
0.4
0.5
D
Single-
Phase
Two-
Phase
Three-
Phase
I
RMS(IN)
I
OUT
35
8
C + 2.84W
×
40
8
C/W = 149
8
C
T
A
+ P
D
×
(R
θ
JC
+R
θ
CS
+R
θ
SA
) < T
J(MAX)
Where:
T
A
= The Ambient Temperature
P
D
= Power Dissipation of each MOSFET
R
θ
JC
= The Thermal Resistance from junction to case
R
θ
CS
= the thermal resistance from case to heat sink
R
θ
SA
= the heat-sink-to-air thermal resistance
T
J(MAX)
= maximum allowable junction temperature
of MOSFET, for example 150
8
C.
T
J
= T
A
+ P
D
×
R
θ
JA
R
θ
SA
< (T
J(MAX)
-T
A
)/P
D
-R
θ
JC
+R
θ
CS
35
8
C + 3.15W
×
40
8
C/W = 161
8
C
Heat Sink Selection
The criteria of selecting heat sink is based on the maxi-
mum allowable junction temperature of the MOSFETs.
That is:
The maximum heat-sink-to-air thermal resistance is cal-
culated as:
In this example, the MOSFET is mounted in the PCB
board with more than 1" square PCB board. Therefore,
the junction temperature for MOSFET can be calculated
as:
Where R
θ
JA
is the junction-to-ambient thermal resistance
with MOSFET on 1" square PCB board and it is avail-
able from MOSFET data sheet.
For MOSFET IRF3704S with D2 package, R
θ
JA
= 40
8
C/
W. Assume ambient temperature is T
A
=35
8
C. For high
side MOSFET, the junction temperature is given as:
For low side MOSFET, IRF3711s, the maximum junc-
tion temperature can be calculated as:
This is the worst case. For conservative consideration,
two IRF3711 can be put in parallel.
相關(guān)PDF資料
PDF描述
IRU3073 SYNCHRONOUS PWM CONTROLLER WITH OVER-CURRENT PROTECTION / LDO CONTROLLER
IRU3073CQ SYNCHRONOUS PWM CONTROLLER WITH OVER-CURRENT PROTECTION / LDO CONTROLLER
IRU3138CS SYNCHRONOUS PWM CONTROLLER FOR TERMINATION POWER SUPPLY APPLICATIONS
IRU3138 SYNCHRONOUS PWM CONTROLLER FOR TERMINATION POWER SUPPLY APPLICATIONS
IRUD360CW40 ULTRAFAST SOFT RECOVERY DIODE
相關(guān)代理商/技術(shù)參數(shù)
參數(shù)描述
IRU3055CQ 制造商:IRF 制造商全稱:International Rectifier 功能描述:5-BIT PROGRAMMABLE 3-PHASE SYNCHRONOUS BUCK CONTROLLER IC
IRU3055CQTR 功能描述:IC CTRL SYNC 3-PHASE 36-QSOP RoHS:否 類別:集成電路 (IC) >> PMIC - 穩(wěn)壓器 - 專用型 系列:- 標準包裝:2,000 系列:- 應(yīng)用:控制器,DSP 輸入電壓:4.5 V ~ 25 V 輸出數(shù):2 輸出電壓:最低可調(diào)至 1.2V 工作溫度:-40°C ~ 85°C 安裝類型:表面貼裝 封裝/外殼:30-TFSOP(0.173",4.40mm 寬) 供應(yīng)商設(shè)備封裝:30-TSSOP 包裝:帶卷 (TR)
IRU3065 制造商:IRF 制造商全稱:International Rectifier 功能描述:POSITIVE TO NEGATIVE DC TO DC CONTROLLER
IRU3065CLTR 功能描述:IC REG CTRLR INV PWM SOT23-6 RoHS:否 類別:集成電路 (IC) >> PMIC - 穩(wěn)壓器 - DC DC 切換控制器 系列:- 標準包裝:4,000 系列:- PWM 型:電壓模式 輸出數(shù):1 頻率 - 最大:1.5MHz 占空比:66.7% 電源電壓:4.75 V ~ 5.25 V 降壓:是 升壓:無 回掃:無 反相:無 倍增器:無 除法器:無 Cuk:無 隔離:無 工作溫度:-40°C ~ 85°C 封裝/外殼:40-VFQFN 裸露焊盤 包裝:帶卷 (TR)
IRU3065CLTRPBF 制造商:IRF 制造商全稱:International Rectifier 功能描述:POSITIVE TO NEGATIVE DC TO DC CONTROLLER