- 您现在的位置：买卖IC网 > PDF目录80263 > LSN-1.2/10-D3-C (MURATA POWER SOLUTIONS INC) 1-OUTPUT 12 W DC-DC REG PWR SUPPLY MODULE PDF资料下载
参数资料
| 型号： | LSN-1.2/10-D3-C |
| 厂商： | MURATA POWER SOLUTIONS INC |
| 元件分类： | 电源模块 |
| 英文描述： | 1-OUTPUT 12 W DC-DC REG PWR SUPPLY MODULE |
| 封装： | ROHS COMPLIANT, SIP-10/11 |
| 文件页数： | 12/14页 |
| 文件大小： | 343K |
| 代理商： | LSN-1.2/10-D3-C |
Start Up Considerations
When power is rst applied to the DC/DC converter, operation is different
than when the converter is running and stabilized. There is some risk of start
up difculties if you do not observe several application features. Lower input
voltage converters may have more problems here since they tend to have
higher input currents. Operation is most critical with any combination of the
following external factors:
1 - Low initial input line voltage and/or poor regulation of the input source.
2 – Full output load current on lower output voltage converters.
3 – Slow slew rate of input voltage.
4 – Longer distance to input voltage source and/or higher external input
source impedance.
5 - Limited or insufcient ground plane. External wiring that is too small.
6 – Too small external input capacitance. Too high ESR.
7 – High output capacitance causing a start up charge overcurrent surge.
8 – Output loads with excessive inductive reactance or constant current
characteristics.
If the input voltage is already at the low limit before power is applied, the start
up surge current may instantaneously reduce the voltage at the input termi-
nals to below the specied minimum voltage. Even if this voltage depression
is very brief, this may interfere with the on-board controller and possibly
cause a failed start. Or the converter may start but the input current load will
now drive the input voltage below its running low limit and the converter will
shut down.
If you measure the input voltage before start up with a Digital Voltmeter
(DVM), the voltage may appear to be adequate. Limited external capacitance
and/or too high a source impedance may cause a short downward spike at
power up, causing an instantaneous voltage drop. Use an oscilloscope not a
DVM to observe this spike. The converter’s soft-start controller is sensitive to
input voltage. What matters here is the actual voltage at the input terminals
at all times.
Symptoms of start-up difculties may include failed started, output oscillation
or brief start up then overcurrent shutdown. Since the input voltage is never
absolutely constant, the converter may start up at some times and not at
others.
Solutions
To improve start up, review the conditions above. One of the better solutions
is to place a moderate size capacitor very close to the input terminals. You
may need two parallel capacitors. A larger electrolytic or tantalum cap sup-
plies the surge current and a smaller parallel low-ESR ceramic cap gives low
AC impedance. Too large an electrolytic capacitor may have higher internal
impedance (ESR) and/or lower the start up slew rate enough to upset the
DC/DC’s controller. Make sure the capacitors can tolerate reected switching
current pulses from the converter.
The capacitors will not help if the input source has poor regulation. A
converter which starts successfully at 3.3 Volts will turn off if the input voltage
decays to below the input voltage theshold, regardless of external capaci-
tance.
Increase the input start up voltage if possible to raise the downward voltage
spike. Also, make sure that the input voltage ramps up in a reasonably short
time (less than a few milliseconds). If possible, move the input source closer
to the converter to reduce ohmic losses in the input wiring. Remember that
the input current is carried both by the wiring and the ground plane return.
Make sure the ground plane uses adequate thickness copper. Run additional
bus wire if necessary.
Any added output capacitor should use just enough capacitance (and no
more) to reduce output noise at the load and to avoid marginal threshold
noise problems with external logic. An output cap will also “decouple”
inductive reactance in the load. Certain kinds of electronic loads include
“constant current” characteristics which destabilize the output with insufcient
capacitance. If the wiring to the eventual load is long, consider placing this
decoupling cap at the load. Use the Remote Sense input to avoid ohmic
voltage drop errors.
An elegant solution to start up problems is to apply the input voltage with the
Remote On/Off control rst in the off setting (for those converters with an
On/Off Control). After the specied start-up delay (usually under 20 mSec),
turn on the converter. The controller will have already been stabilized. The
short delay will not be noticed in most applications. Be aware of applications
which need “power management” (phased start up).
Finally, it is challenging to model some application circuits with absolute del-
ity. How low is the resistance of your ground plane? What is the inductance
(and distributed capacitance) of external wiring? Even a detailed mathemati-
cal model may not get all aspects of your circuit. Therefore it is difcult to
give cap values which serve all applications. Some experimentation may be
required.
LSN-10A D3 Models
Single Output, Non-Isolated, 3.3VIN, 1-2.5VOUT, 10A, DC/DC's in SIP Packages
www.murata-ps.com
email: sales@murata-ps.com
16 Dec 2009
MDC_LSN10A-D3.B03 Page 7 of 14
相关PDF资料 |
PDF描述 |
|---|---|
| L432ISCT | 1-OUTPUT TWO TERM VOLTAGE REFERENCE, PDSO3 |
| LK4003-9RV3TB1 | 1-OUTPUT AC-DC PWR FACTOR CORR MODULE |
| LS3718-S28-T | SPECIALTY ANALOG CIRCUIT, PDSO28 |
| LS2812S/CKA | 1-OUTPUT 30 W DC-DC REG PWR SUPPLY MODULE |
| LX1552CM | 1 A SWITCHING CONTROLLER, 500 kHz SWITCHING FREQ-MAX, PDIP8 |
相关代理商/技术参数 |
参数描述 |
|---|---|
| LSN1210D5 | 制造商:Datel 功能描述: |
| LSN1210D5C | 制造商:Datel 功能描述: |
| LSN1510D12J | 制造商:Datel 功能描述: |
| LSN1510D5 | 制造商:Datel 功能描述: |
| LSN16A-D12 | 制造商:MURATA 制造商全称:Murata Manufacturing Co., Ltd. 功能描述:Single Output, Non-Isolated, 12VIN, 0.75-5VOUT 16 Amp in DC/DCs SIP Packages |
发布紧急采购，3分钟左右您将得到回复。