參數(shù)資料
型號: IRU3146CF
廠商: International Rectifier
英文描述: DUAL SYNCHRONOUS PWM CONTROLLER WITH CURRENT SHARING CIRCUITRY AND AUTO-RESTART
中文描述: 雙同步PWM控制器,帶有均流電路和自動重新啟動
文件頁數(shù): 8/30頁
文件大?。?/td> 528K
代理商: IRU3146CF
8
Rev. 1.1
6/25/04
IRU3146
www.irf.com
L1
R
SET
IRU3146
OCSet
I
OCSET
V
OUT
Hiccup
Control
Q1
Q2
Figure 9 - Diagram of the over current sensing.
V
OCSET
= I
OCSET
×
R
SET
-R
DS(ON)
×
i
L
---(2)
V
OCSET
= I
OCSET
×
R
SET
- R
DS(ON)
×
I
L
= 0
R
SET
×
I
OCSET
The critical inductor current can be calculated by set-
ting:
I
SET
= I
L(CRITICAL)
=
---(3)
R
DS(ON)
The internal current source develops a voltage across
R
SET
. When the low side switch is turned on, the induc-
tor current flows through the Q2 and results a voltage
which is given by:
The value of R
SET
should be checked in an actual
circuit to ensure that the Over Current Protection
circuit activates as expected. The IRU3146 current
limit is designed primarily as disaster preventing, "no
blow up" circuit, and is not useful as a precision
current regulator.
In two independent mode, the output of each channel
is protected independently which means if one output
is under overload or short circuit condition, the other
output will remain functional. The OCP set limit can be
programmed to different levels by using the external
resistors. This is valid for both hiccup mode and latch
up mode.
In 2-phase configuration, the OCP's output depends on
any one channel, which means as soon as one
channel goes to overload or short circuit condition the
output will enter either hiccup or latch-up, dependes on
status of Hiccup pin.
For a given start up time, the soft-start capacitor can be
calculated by:
C
SS
25
μ
A
×
T
START
/1V
Over-Current Protection
The IRU3146 can provide two different schemes for Over-
Current Protection (OCP). When the pin Hiccup is pulled
high, the OCP will operate in hiccup mode. In this mode,
during overload or short circuit, the outputs enter hiccup
mode and stay in that mode until the overload or short
circuit is removed. The converter will automatically re-
cover.
When the Hiccup pin is pulled low, the OCP scheme
will be changed to the latch up type, in this mode the
converter will be turned off during Overcurrent or short
circuit. The power needs to be recycled for normal
operation.
Each phase has its own independent OCP circuitry.
The OCP is performed by sensing current through the
R
DS(ON)
of low side MOSFET. As shown in Figure 9, an
external resistor (R
SET
) is connected between OCSet pin
and the drain of low side MOSFET (Q2) which sets the
current limit set point.
The soft-start is part of Over Current Protection scheme,
during the overload or short circuit condition the external
soft start capacitors will be charged and discharged in
certain slope rate to achieve the hiccup mode function.
Out-of-Phase Operation
The IRU3146 drives its two output stages 180 out-of-
phase. In 2-phase configuration, the two inductor ripple
currents cancel each other and result in a reduction of
the output current ripple and yield a smaller output ca-
pacitor for the same ripple voltage requirement.
In single input voltage applications, the input ripple cur-
rent reduces. This result in much smaller input capacitor's
RMS current and reduces the input capacitor quantity.
SS1 / SD
20
25uA
3uA
Hiccup
If using one soft start capacitor in dual configuration for a
precise power up the OCP needs to be set to latch mode.
Figure 8 - 3uA current source for discharging soft
start-capacitor during Hiccup mode
相關(guān)PDF資料
PDF描述
IRXXH214 POWIRLIGHTTM REFERENCE DESIGN : COMPACT BALLAST
IRXXH224 POWIRLIGHTTM REFERENCE DESIGN : COMPACT BALLAST
IRXXH310 POWIRLIGHTTM REFERENCE DESIGN : COMPACT BALLAST
IRXXH320 POWIRLIGHTTM REFERENCE DESIGN : COMPACT BALLAST
IRXXH420 POWIRLIGHTTM REFERENCE DESIGN : COMPACT BALLAST
相關(guān)代理商/技術(shù)參數(shù)
參數(shù)描述
IRU3146CFTR 功能描述:IC REG CTRLR BUCK PWM VM 28TSSOP RoHS:否 類別:集成電路 (IC) >> PMIC - 穩(wěn)壓器 - DC DC 切換控制器 系列:- 特色產(chǎn)品:LM3753/54 Scalable 2-Phase Synchronous Buck Controllers 標準包裝:1 系列:PowerWise® PWM 型:電壓模式 輸出數(shù):1 頻率 - 最大:1MHz 占空比:81% 電源電壓:4.5 V ~ 18 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:-5°C ~ 125°C 封裝/外殼:32-WFQFN 裸露焊盤 包裝:Digi-Reel® 產(chǎn)品目錄頁面:1303 (CN2011-ZH PDF) 其它名稱:LM3754SQDKR
IRU431AL 制造商:IRF 制造商全稱:International Rectifier 功能描述:LOW -VOLTAGE ADJUSTABLE PRECISION SHUNT REGULATOR
IRU431ALCL3 制造商:IRF 制造商全稱:International Rectifier 功能描述:LOW -VOLTAGE ADJUSTABLE PRECISION SHUNT REGULATOR
IRU431ALCL3TR 功能描述:IC VREF SHUNT PREC ADJ SOT-23-3 RoHS:否 類別:集成電路 (IC) >> PMIC - 電壓基準 系列:- 標準包裝:3,000 系列:- 基準類型:旁路,精度 輸出電壓:5V 容差:±0.5% 溫度系數(shù):100ppm/°C 輸入電壓:- 通道數(shù):1 電流 - 陰極:80µA 電流 - 靜態(tài):- 電流 - 輸出:15mA 工作溫度:-40°C ~ 85°C 安裝類型:表面貼裝 封裝/外殼:TO-236-3,SC-59,SOT-23-3 供應(yīng)商設(shè)備封裝:SOT-23-3 包裝:帶卷 (TR) 其它名稱:LM4040CIM3-5.0MLTRLM4040CIM3-5.0MLTR-ND
IRU431ALCL5 制造商:IRF 制造商全稱:International Rectifier 功能描述:LOW -VOLTAGE ADJUSTABLE PRECISION SHUNT REGULATOR