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参数资料
| 型号： | L6910GTR |
| 厂商： | STMICROELECTRONICS |
| 元件分类： | 稳压器 |
| 英文描述： | 1.3 A SWITCHING CONTROLLER, 1000 kHz SWITCHING FREQ-MAX, PDSO16 |
| 封装： | SO-16 |
| 文件页数： | 25/26页 |
| 文件大小： | 1046K |
| 代理商： | L6910GTR |
L6910G
8/26
Overcurrent protection is performed by the device comparing the drop across the high side MOS, due to the
RDSON, with the voltage across the external resistor (ROCS) connected between the OCSET pin and drain of the
upper MOS. Thus the overcurrent threshold (IP) can be calculated with the following relationship:
Where the typical value of IOCS is 200A. To calculate the ROCS value it must be considered the maximum
RdsON (also the variation with temperature) and the minimum value of IOCS. To avoid undesirable trigger of
overcurrent protection this relationship must be satisfied:
Where
I is the inductance ripple current and IOUTMAX is the maximum output current.
In case of over current detectionthe soft start capacitor is discharged with constant current (10
A typ.) and when
the SS pin reaches 0.5V the soft start phase is restarted. During the soft start the over-current protection is al-
ways active and if such kind of event occurs, the device turns off both mosfets, and the SS capacitor is dis-
charged again (after reaching the upper threshold of about 4V). The system is now working in HICCUP mode,
as shown in figure 8. After removing the cause of the over-current, the device restart working normally without
power supplies turn off and on.
I
P
R
OCS
I
OCS
R
dsON
---------------------------------
=
I
P
I
OUTMAX
I
2
-----
+
≥
I
PEAK
=
Figure 8. Hiccup Mode
Figure 9. Inductor Ripple Current vs. Vout
CH1 = SS; CH4 = Inductor current
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
4.6 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
IL between 20% and 30% of the maximum output current. The inductance value can be cal-
culated with this relationship:
Where fSW is the switching frequency, VIN is the input voltage and VOUT is the output voltage. Figure 9 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 cur-
rent is supplied by the output capacitors. Minimizing the response time can minimize the output capacitance
required.
L
V
IN
V
OUT
–
f
sw
I
L
------------------------------
V
OUT
V
IN
---------------
=
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相关代理商/技术参数 |
参数描述 |
|---|---|
| L6910R | 功能描述:DC/DC 开关控制器 5.0 to 12V Step-Down 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 |
| L6910RTR | 功能描述:DC/DC 开关控制器 5.0 to 12V Step-Down 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 |
| L6910S | 功能描述:DC/DC 开关控制器 5.0 to 12V Step-Down 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 |
| L6910STR | 功能描述:DC/DC 开关控制器 5.0 to 12V Step-Down 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 |
| L6910TR | 功能描述:DC/DC 开关控制器 5.0 to 12V Step-Down 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 |
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