参数资料
型号: L6911E
厂商: STMICROELECTRONICS
元件分类: 稳压器
英文描述: 1.3 A SWITCHING CONTROLLER, 1000 kHz SWITCHING FREQ-MAX, PDSO20
封装: SO-20
文件页数: 8/34页
文件大小: 558K
代理商: L6911E
Obsolete
Product(s)
- Obsolete
Product(s)
Obsolete
Product(s)
- Obsolete
Product(s)
Device description
L6911E
16/34
Figure 7.
Hiccup mode and Inductor ripple current vs. VOUT
5.6
Inductor design
The inductance value is defined by a compromise between the transient response time, the
efficiency, the cost and the size. The inductor has to be calculated to sustain the output and
the input voltage variation to maintain the ripple current
I
L between 20% and 30% of the
maximum output current. The inductance value can be calculated with this relationship:
Equation 6
Where fSW is the switching frequency, VIN is the input voltage and VOUT is the output
voltage. Figure 7 b shows the ripple current vs. the output voltage for different values of the
inductor, with vin = 5V and Vin = 12V.
Increasing the value of the inductance reduces the ripple current but, at the same time,
reduces the converter response time to a load transient. If the compensation network is well
designed, the device is able to open or close the duty cycle up to 100% or down to 0%. The
response time is now the time required by the inductor to change its current from initial to
final value. Since the inductor has not finished its charging time, the output current is
supplied by the output capacitors. Minimizing the response time can minimize the output
capacitance required.
The response time to a load transient is different for the application or the removal of the
load: if during the application of the load the inductor is charged by a voltage equal to the
difference between the input and the output voltage, during the removal it is discharged only
by the output voltage. The following expressions give approximate response time for
I load
transient in case of enough fast compensation network response:
0
1
2
3
4
5
6
7
8
9
0.5
1.5
2.5
3.5
Output Voltage [V]
Inductor
Ripple
[A]
L=3
H,
Vin=12V
L=2
H,
Vin=12V
L=1.5
H, Vin=12V
L=2
H,
Vin=5V
L=1.5
H,
Vin=5V
L=3
H, Vin=5V
a)
b)
L
V
IN
V
OUT
f
s
I
L
------------------------------
V
OUT
V
IN
--------------
=
相关PDF资料
PDF描述
L6911ETR 1.3 A SWITCHING CONTROLLER, 1000 kHz SWITCHING FREQ-MAX, PDSO20
L6924U013 POWER SUPPLY SUPPORT CKT, PQCC16
L6924U013TR POWER SUPPLY SUPPORT CKT, PQCC16
L6924U POWER SUPPLY SUPPORT CKT, QCC16
L6926D1013TR 1.65 A SWITCHING REGULATOR, 800 kHz SWITCHING FREQ-MAX, PDSO8
相关代理商/技术参数
参数描述
L6911E_07 制造商:STMICROELECTRONICS 制造商全称:STMicroelectronics 功能描述:5-Bit programmable step down controller with synchronous rectification
L6911ETR 功能描述:DC/DC 开关控制器 5B PROGRAMMABLE STEP DOWN CONTROLLER RoHS:否 制造商:Texas Instruments 输入电压:6 V to 100 V 开关频率: 输出电压:1.215 V to 80 V 输出电流:3.5 A 输出端数量:1 最大工作温度:+ 125 C 安装风格: 封装 / 箱体:CPAK
L6912-2 制造商:Thomas & Betts 功能描述:1/2 CORD GRIP CONNECTOR,2/BG
L6913-1 制造商:Thomas & Betts 功能描述:1/2 CORD GRIP CONNECTOR,1/BG
L6913-2 制造商:Thomas & Betts 功能描述:1/2 CORD GRIP CONNECTOR,2/BG