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参数资料
| 型号： | ISL6227CA |
| 厂商： | INTERSIL CORP |
| 元件分类： | 稳压器 |
| 英文描述： | Dual Mobile-Friendly PWM Controller with DDR Option |
| 中文描述： | DUAL SWITCHING CONTROLLER, 345 kHz SWITCHING FREQ-MAX, PDSO28 |
| 封装： | 0.150 INCH, PLASTIC, SSOP-28 |
| 文件页数： | 10/27页 |
| 文件大小： | 834K |
| 代理商： | ISL6227CA |
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18
FN9094.7
May 4, 2009
Its transfer function can be written as Equation 12:
where:
fz1 = 6.98kHz, fz2 = 380kHz, and fp1 = 137kHz
Outside the ISL6227 chip, a capacitor Cz can be placed in
parallel with the top resistor in the feedback resistor divider,
as shown in Figure 34. In this case the transfer function from
the output voltage to the middle point of the divider can be
written as Equation 13:
The ratio of R1 and R2 is determined by the output voltage
set point; therefore, the position of the pole and zero
frequency in the above equation may not be far apart;
however, they can improve the loop gain and phase margin
with the proper design.
The Cz can bring the high frequency transient output voltage
variation directly to the VSEN pin to cause the PGOOD drop.
Such an effect should be considered in the selection of Cz.
From the analysis above, the system loop gain can be
written as Equation 14:
Figure 39 shows the composition of the system loop gain. As
shown in the graph, the power stage becomes a well
damped second order system as compared to the LC filter
characteristics. The ESR zero is so close to the high
frequency pole that they cancel each other out. The power
stage behaves like a first order system. With an internal
compensator, the loop gain transfer function has a cross
over frequency at about 30kHz. With a given set of
parameters, including the MOSFET rDS(ON), current sense
resistor RCS, output LC filter, and voltage feedback network,
the system loop gain can be accurately analyzed and
modified by the system designers based on the application
requirements.
Gate Control Logic
The gate control logic translates generated PWM signals
into gate drive signals providing necessary amplification,
level shift, and shoot-through protection. It bears some
functions that help to optimize the IC performance over a
wide range of the operational conditions. As MOSFET
switching time can vary dramatically from type to type, and
with the input voltage, the gate control logic provides
adaptive dead time by monitoring real gate waveforms of
both the upper and the lower MOSFETs.
Dual-Step Conversion
The ISL6227 dual channel controller can be used either in
power systems with a single-stage power conversion, when
the battery power is converted into the desired output
voltage in one step, or in the systems where some
intermediate voltages are initially established. The choice of
the approach may be dictated by the overall system design
criteria, or the approach may be a matter of voltages
available to the system designer, as in the case of PCI card
applications.
When the output voltage is regulated from low voltage such
as 5V, the feed-forward ramp may become too shallow,
creating the possibility of duty-factor jitter; this is particularly
relevant in a noisy environment. Noise susceptibility, when
operating from low level regulated power sources, can be
improved by connecting the VIN pin to ground, by which the
feed-forward ramp generator will be internally reconnected
from the VIN pin to the VCC pin, and the ramp slew rate will
be doubled.
FIGURE 38. THE INTERNAL COMPENSATOR
+
-
1.25pF
1M
15pF
500k
300k
VSEN
0.9V
TO PWM
COMPARATOR
4.4k
Vc
ISEN
Gcomp s
()
1.857
10
5
s
2
πf
z1
---------------
1
+
s
2
πf
z2
---------------
1
+
s
2
πf
p1
---------------
1
+
---------------------------------------------------------------------------------------------
=
(EQ.12)
Gfd s
()
R
2
R
1
R
2
+
---------------------
sR
1Cz
1
+
sR
1
R
2
||
()C
z
1
+
----------------------------------------------
=
(EQ.13)
Gloop s
()
Gs
() Gcomp s
()
Gfd
=
s
()
(EQ.14)
FIGURE 39. THE BODE PLOT OF THE LC FILTER,
COMPENSATOR, CONTROL TO OUTPUT
VOLTAGE TRANSFER FUNCTION, AND SYSTEM
LOOP GAIN
0
10
20
30
40
50
60
100
1103
FREQUENCY (Hz)
G
A
IN
(
d
B)
-10
-20
-30
-40
-50
-60
1104
1105
1106
COMPENSATOR
LC FILTER
VO/VC
LOOP GAIN
ISL6227
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| ISL6227CA-T | Dual Mobile-Friendly PWM Controller with DDR Option |
| ISL6227CAZ | Dual Mobile-Friendly PWM Controller with DDR Option |
| ISL6227CAZ-T | Dual Mobile-Friendly PWM Controller with DDR Option |
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相关代理商/技术参数 |
参数描述 |
|---|---|
| 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 |
| ISL6227CAZ-T | 功能描述:电流型 PWM 控制器 VER OF ISL6227CA-T 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 |
| ISL6227CAZ-TS2698 | 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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