- 您現在的位置：買賣IC網 > PDF目錄383239 > L6997STR (意法半導體) STEP DOWN CONTROLLER FOR LOW VOLTAGE OPERATIONS PDF資料下載
參數資料
| 型號： | L6997STR |
| 廠商： | 意法半導體 |
| 英文描述： | STEP DOWN CONTROLLER FOR LOW VOLTAGE OPERATIONS |
| 中文描述： | 降壓控制器低電壓運作 |
| 文件頁數： | 19/30頁 |
| 文件大?。?/td> | 515K |
| 代理商： | L6997STR |
第1頁第2頁第3頁第4頁第5頁第6頁第7頁第8頁第9頁第10頁第11頁第12頁第13頁第14頁第15頁第16頁第17頁第18頁當前第19頁第20頁第21頁第22頁第23頁第24頁第25頁第26頁第27頁第28頁第29頁第30頁
19/30
L6997S
6.9 Soft start capacitor
Considering the soft start equations (Eq. 11) at page 10, it can be found:
C
SS
= 150pF
The equations are valid without load. When an active load is present the equations result more complex; further
some active loads have unexpected effect, as higher current than the expected one during the soft start, can
change the start up time.
In this case the capacitor value can be selected on the application; anyway the Eq11 gives an idea about the
C
SS
value.
6.10Sink mode
Figure 16. Efficiency vs output current
7
The evaluation board shows the device operation in these conditions: V
IN
= 3.3V V
OUT
= 1.8V I
OUT
= 15A, F
SW
= 200KHz without the integrator feature. The evaluation board has two different input voltages: V
CC
[from 3V to
5.5V] used to supply the device and the V
IN
[up to 35V] for the power conversion. In this way, changing the pow-
er components configuration (C
IN
, C
OUT
, MOSFETs, L) it is possible evaluate the device performance in differ-
ent conditions. It is also possible to mount a linear regulator on board used to generate the V
CC
. On the top side
are also present two switches and four jumpers. The two switches have different goals: the one nearest to the
V
CC
is used to turn on/off the device when the V
CC
and V
IN
are both present; the other one, near to R11 is used
to turn on/off the PFM feature. The device can be turned on also with the power supply, but a correct start up
sequence is mandatory. V
IN
has to be raised first and then the V
CC
can be applied too. If the correct sequence
is not respected the device will not start up. The jumpers are used to set the integrator feature and to use the
remote sensing; for more information refers to the Jumpers table. Sometimes when using the integrator config-
uration a low frequency filter is required in order to reduce the noise interaction. The pole value should be at
least five times higher than the switching frequency. The low pass filter should be inserted in this way: the re-
sistor, in the place of the INT jumper position and the capacitor between the resistor and ground (refers to the
schematic).
15A DEMO BOARD DESCRIPTION
0,0
10,0
20,0
30,0
40,0
50,0
60,0
70,0
80,0
90,0
100,0
0,0
1,0
2,0
3,0
4,0
5,0
Current [A]
Eff [%]
相關PDF資料 |
PDF描述 |
|---|---|
| L702B | 2A QUAD DARLINGTON SWITCH |
| L702N | 2A QUAD DARLINGTON SWITCH |
| L7203 | SMOOTH DRIVE SPINDLE MOTOR FOR OPTICAL DRIVE APPLICATION WITH POWER INTEGRATED |
| L7203S | SMOOTH DRIVE SPINDLE MOTOR FOR OPTICAL DRIVE APPLICATION WITH POWER INTEGRATED |
| L7208 | Portable consumer electronics spindle and VCM motor controller |
相關代理商/技術參數 |
參數描述 |
|---|---|
| L6998-0 | 制造商:Johanson Manufacturing 功能描述:TUNING ELEMENT |
| L6998-1 | 制造商:Johanson Manufacturing 功能描述:TUNING ELEMENT |
| L6998-5 | 制造商:Johanson Manufacturing 功能描述:TUNING ELEMENT |
| L6998-6 | 制造商:Johanson Manufacturing 功能描述:TUNING ELEMENT |
| L6999 | 制造商:HAMAMATSU 制造商全稱:Hamamatsu Corporation 功能描述:The best light source is supported by the best electrode technology |
發(fā)布緊急采購，3分鐘左右您將得到回復。