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参数资料
| 型号： | ISL6227 |
| 厂商： | Intersil Corporation |
| 英文描述： | Dual Mobile-Friendly PWM Controller with DDR Option |
| 中文描述： | 双移动友好PWM控制器与DDR选项 |
| 文件页数： | 9/26页 |
| 文件大小： | 897K |
| 代理商： | ISL6227 |
17
The resistor connected to the ISEN pin sets the gain in the
current sensing. The following expression estimates the
required value of the current sense resistor, depending on
the maximum continuous load current, and the value of the
MOSFETs rDS(ON), assuming the ISEN pin sources 75A
current.
Because the current sensing circuit is a sample-and-hold
type, the information obtained at the last moment of the
sampling is used. This current sensing circuit samples the
inductor current very close to its peak value. The current
feedback essentially injects a resistor Ri in series with the
original LC filter as shown in Figure 37, where the sample-
and-hold effect of the current loop has been ignored. Vc and
Vo are small signal components extracted from its DC
operation points.
The value of the injected resistor can be estimated by:
Ri is in k, and RDS and RCS are in . VIN divided by
Vramp, is defined as Gm, which is a constant 8 or 18 dB for
both channels in dual switcher applications, when VIN is
above 3V. Refer to Table 1 for the ramp amplitude in different
VIN pin connections. The feed-forward effect of the VIN is
reflected in Gm. Vc is defined as the error amplifier output
voltage.
The small signal transfer function from the error amplifier
output voltage Vc to the output voltage Vo can be written in
the following expression:
The dc gain is derived by shorting the inductor and opening
the capacitor. There is one zero and two poles in this transfer
function. The zero is related to ESR and the output
capacitor.
The first pole is a low frequency pole associated with the
output capacitor and its charging resistors. The inductor can
be regarded as short. The second pole is the high frequency
pole related to the inductor. At high frequency the output
capacitor can be regarded as a short circuit. By
approximation, the poles and zero are inversely proportional
to the time constants, associated with inductor and capacitor,
by the following expressions:
Since the current loop separates the LC resonant poles into
two distant poles, and ESR zero tends to cancel the high
frequency pole, the second order system behaves like a first
order system. This control method simplifies the design of
the internal compensator and makes it possible to
accommodate many applications having a wide range of
parameters.
TABLE 1. PWM COMPARATOR RAMP AMPLITUDE FOR
DUAL SWITCHER APPLICATION
VIN PIN CONNECTIONS
VRAMP
AMPLITUDE
Ch1 and Ch2 Input Voltage Input voltage >4.2V
Vin/8
Input voltage <4.2V
1.25V
GND
1.25V
RCS
IMAX rDS ON
()
75
A
------------------------------------------
=
140
–
(EQ. 6)
FIGURE 37. THE EQUIVALENT CIRCUIT OF THE POWER
STAGE WITH CURRENT LOOP INCLUDED
+
-
Gm*Vc
Ri
Lo
DCR
Co
Ro
Vo
ESR
+
-
Ri
VIN
Vramp
-----------------
rDS ON
()
RCS 140
+
---------------------------- 4.4k
=
(EQ. 7)
TABLE 2. PWM COMPARATOR RAMP VOLTAGE AMPLITUDE
FOR DDR APPLICATION
VIN PIN CONNECTION
VRAMP
AMPLITUDE
Ch1
Input Voltage
Input voltage >4.2V
Vin/8
Input voltage <4.2V
1.25V
GND
1.25V
Ch2
Input voltage >4.2V
0.625V
GND
1.25V
Gs
()
Gm
Ro
Ri DCR Ro
++
---------------------------------------
s
Wz
--------- 1
+
s
Wp1
------------- 1
+
s
Wp2
------------- 1
+
---------------------------------------------------------
=
(EQ. 8)
Wz
1
ESR*Co
------------------------
=
(EQ. 9)
Wp1
1
ESR
Ri DCR
+
() R
o
||
+
()*C
o
-------------------------------------------------------------------------------
=
(EQ.10)
Wp2
Ri DCR ESR
++
Ro
||
Lo
----------------------------------------------------------
=
(EQ.11)
ISL6227
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相关代理商/技术参数 |
参数描述 |
|---|---|
| ISL6227_07 | 制造商:INTERSIL 制造商全称:Intersil Corporation 功能描述:Dual Mobile-Friendly PWM Controller with DDR Option |
| ISL6227CA | 功能描述:IC CONTROLLER DDR, DDR2 28QSOP RoHS:否 类别:集成电路 (IC) >> PMIC - 稳压器 - 专用型 系列:- 产品培训模块:Lead (SnPb) Finish for COTS Obsolescence Mitigation Program 标准包装:2,000 系列:- 应用:电源，ICERA E400，E450 输入电压:4.1 V ~ 5.5 V 输出数:10 输出电压:可编程 工作温度:-40°C ~ 85°C 安装类型:表面贴装 封装/外壳:42-WFBGA，WLCSP 供应商设备封装:42-WLP 包装:带卷 (TR) |
| ISL6227CA-T | 功能描述:IC CONTROLLER DDR, DDR2 28QSOP RoHS:否 类别:集成电路 (IC) >> PMIC - 稳压器 - 专用型 系列:- 产品培训模块:Lead (SnPb) Finish for COTS Obsolescence Mitigation Program 标准包装:2,000 系列:- 应用:电源，ICERA E400，E450 输入电压:4.1 V ~ 5.5 V 输出数:10 输出电压:可编程 工作温度:-40°C ~ 85°C 安装类型:表面贴装 封装/外壳:42-WFBGA，WLCSP 供应商设备封装:42-WLP 包装:带卷 (TR) |
| ISL6227CAZ | 功能描述:电流型 PWM 控制器 VER OF ISL6227CA RoHS:否 制造商:Texas Instruments 开关频率:27 KHz 上升时间: 下降时间: 工作电源电压:6 V to 15 V 工作电源电流:1.5 mA 输出端数量:1 最大工作温度:+ 105 C 安装风格:SMD/SMT 封装 / 箱体:TSSOP-14 |
| ISL6227CAZS2698 | 功能描述:IC CONTROLLER DDR, DDR2 28QSOP RoHS:是 类别:集成电路 (IC) >> PMIC - 稳压器 - 专用型 系列:- 标准包装:43 系列:- 应用:控制器，Intel VR11 输入电压:5 V ~ 12 V 输出数:1 输出电压:0.5 V ~ 1.6 V 工作温度:-40°C ~ 85°C 安装类型:表面贴装 封装/外壳:48-VFQFN 裸露焊盘 供应商设备封装:48-QFN（7x7） 包装:管件 |
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