- 您現(xiàn)在的位置：買賣IC網(wǎng) > PDF目錄383148 > ISL6444 (Intersil Corporation) Dual PWM Controller with DDR Memory Option for Gateway Applications(帶DDR存儲器選項(xiàng)的網(wǎng)關(guān)專用雙PWM控制器) PDF資料下載
參數(shù)資料
| 型號： | ISL6444 |
| 廠商： | Intersil Corporation |
| 英文描述： | Dual PWM Controller with DDR Memory Option for Gateway Applications(帶DDR存儲器選項(xiàng)的網(wǎng)關(guān)專用雙PWM控制器) |
| 中文描述： | 雙PWM控制器的DDR網(wǎng)關(guān)應(yīng)用（帶的DDR存儲器選項(xiàng)的網(wǎng)關(guān)專用雙脈寬調(diào)制控制器內(nèi)存選項(xiàng)） |
| 文件頁數(shù)： | 8/19頁 |
| 文件大?。?/td> | 372K |
| 代理商： | ISL6444 |
8
FN9069.3
April 12, 2007
Description
Operation
The ISL6444 is a dual channel PWM controller intended for
use in power supplies for graphic chipset, SDRAM, DDR
DRAM or other low voltage power applications in modern
notebook and sub-notebook PCs. The IC integrates two
control circuits for two synchronous buck converters. The
output voltage of each controller can be set in the range of
0.9V to 5.5V by an external resistive divider. Out-of-phase
operation with 180° phase shift reduces input current ripple.
The synchronous buck converters can operate from either
an unregulated DC source such as a notebook battery with a
voltage ranging from 5.0V to 24V, or from a regulated system
rail of 3.3V or 5V. In either mode of operation, the controller
is biased from the +5V source.
The controllers operate in the current mode with input
voltage feed-forward for simplified feedback loop
compensation and reduced effect of the input voltage
variation. An integrated feedback loop compensation
dramatically reduces the number of external components.
Depending on the load level, converters can operate either
in a fixed-frequency mode or in a hysteretic mode.
Switch-over to the hysteretic mode operation at light loads
improves the converters' efficiency and prolongs battery run
time. The hysteretic mode of operation can be inhibited
independently for each channel if a variable frequency
operation is not desired.
The ISL6444 has a special means to rearrange its internal
architecture into a complete DDR solution. When DDR input
is set high, the second channel can provide the capability to
track the output voltage of the first channel. The buffered
reference voltage required by DDR memory chips is also
provided.
Initialization
The ISL6444 initializes if at least one of the enable pins is
set high. The Power-On Reset (POR) function continually
monitors the bias supply voltage on the VCC pin and initiates
soft-start operation after the input supply voltage exceeds
4.5V. Should this voltage drop lower than 4.0V, the POR
disables the chip.
Soft-Start
When soft start is initiated, the voltage on the SOFT pin of
the enabled channel starts to ramp gradually due to the 5
μ
A
current sourced into the external soft-start capacitor. The
output voltage starts to follow the soft-start voltage.
When the SOFT pin voltage reaches a level of 0.9V, the
output voltage comes into regulation while the soft-start pin
voltage continues to rise. When the SOFT voltage reaches
1.5V, the power good (PGOOD), the mode control, and the
fault functions are enabled, as depicted in Figure 1.
This completes the soft start sequence. Further rise of pin
voltage does not affect the output voltage. During the
soft-start, the converter always operates in continuous
conduction mode independently of the load level or FCCM
pin potential.
The soft-start time (the time from the moment when EN
becomes high to the moment when PGOOD is reported) is
determined by Equation 1.
The time it takes the output voltage to come into regulation
can be obtained from Equation 2.
Having such a spread between the time when the output
voltage reaches the regulation point and the moment when
PGOOD is reported allows for a fault-safe test mode by
means of an external circuit that clamps the SOFT pin
voltage on the level 0.9V < V
SOFT
< 1.5V.
Output Voltage Program
The output voltage of either channel is set by a resistive divider
from the output to ground. The center point of the divider is
connected to VSEN pin as shown in Figure 2. The output
voltage value is determined by Equation 3.
)
Where 0.9V is the value of the internal reference. The VSEN
pin voltage is also used by the controller for the power good
function and to detect undervoltage and overvoltage
conditions.
Automatic Operation Mode Control
In nominal currents the synchronous buck converter
operates in continuous-conduction constant-frequency
mode. This mode of operation achieves higher efficiency
due to the substantially lower voltage drop across the
FIGURE 1. START-UP
Ch3 1.0V
Ch2 2.0V
Ch4 5.0V
M1.00ms
Ch1 5.0V
3
2
4
1
EN
0.9V1.5V
SOFT
VOUT
PGOOD
T
SOFT
----------------------------------
=
(EQ. 1)
T
RISE
0.6
T
SOFT
×
=
(EQ. 2)
V
O
-----------------------------+
=
(EQ. 3)
ISL6444
相關(guān)PDF資料 |
PDF描述 |
|---|---|
| ISL6445 | 1.4MHz Dual, 180 Degree Out-of-Phase, Step-Down PWM Controller |
| ISL6445IAZ | 1.4MHz Dual, 180 Degree Out-of-Phase, Step-Down PWM Controller |
| ISL6445IAZ-TK | 1.4MHz Dual, 180 Degree Out-of-Phase, Step-Down PWM Controller |
| ISL6455 | Triple Output Regulator with Single Synchronous Buck and Dual LDO(帶單同步降壓和雙LDO的三路輸出調(diào)節(jié)器) |
| ISL6455A | Triple Output Regulator with Single Synchronous Buck and Dual LDO(帶單同步降壓和雙LDO的三路輸出調(diào)節(jié)器) |
相關(guān)代理商/技術(shù)參數(shù) |
參數(shù)描述 |
|---|---|
| ISL6444CA | 功能描述:電流型 PWM 控制器 Dual with DDR Memory RoHS:否 制造商:Texas Instruments 開關(guān)頻率:27 KHz 上升時(shí)間: 下降時(shí)間: 工作電源電壓:6 V to 15 V 工作電源電流:1.5 mA 輸出端數(shù)量:1 最大工作溫度:+ 105 C 安裝風(fēng)格:SMD/SMT 封裝 / 箱體:TSSOP-14 |
| ISL6444CA-T | 功能描述:IC CONTROLLER DDR 28-QSOP RoHS:否 類別:集成電路 (IC) >> PMIC - 穩(wěn)壓器 - 專用型 系列:- 產(chǎn)品培訓(xùn)模塊:Lead (SnPb) Finish for COTS Obsolescence Mitigation Program 標(biāo)準(zhǔn)包裝:2,000 系列:- 應(yīng)用:電源，ICERA E400，E450 輸入電壓:4.1 V ~ 5.5 V 輸出數(shù):10 輸出電壓:可編程 工作溫度:-40°C ~ 85°C 安裝類型:表面貼裝 封裝/外殼:42-WFBGA，WLCSP 供應(yīng)商設(shè)備封裝:42-WLP 包裝:帶卷 (TR) |
| ISL6444CAZ | 功能描述:IC CONTROLLER DDR 28-QSOP RoHS:是 類別:集成電路 (IC) >> PMIC - 穩(wěn)壓器 - 專用型 系列:- 標(biāo)準(zhǔn)包裝:43 系列:- 應(yīng)用:控制器，Intel VR11 輸入電壓:5 V ~ 12 V 輸出數(shù):1 輸出電壓:0.5 V ~ 1.6 V 工作溫度:-40°C ~ 85°C 安裝類型:表面貼裝 封裝/外殼:48-VFQFN 裸露焊盤 供應(yīng)商設(shè)備封裝:48-QFN（7x7） 包裝:管件 |
| ISL6444CAZT | 制造商:Intersil Corporation 功能描述: |
| ISL6444CAZ-T | 功能描述:IC CONTROLLER DDR 28-QSOP RoHS:是 類別:集成電路 (IC) >> PMIC - 穩(wěn)壓器 - 專用型 系列:- 標(biāo)準(zhǔn)包裝:43 系列:- 應(yīng)用:控制器，Intel VR11 輸入電壓:5 V ~ 12 V 輸出數(shù):1 輸出電壓:0.5 V ~ 1.6 V 工作溫度:-40°C ~ 85°C 安裝類型:表面貼裝 封裝/外殼:48-VFQFN 裸露焊盤 供應(yīng)商設(shè)備封裝:48-QFN（7x7） 包裝:管件 |
發(fā)布緊急采購，3分鐘左右您將得到回復(fù)。