- 您現(xiàn)在的位置：買賣IC網(wǎng) > PDF目錄16612 > DC1561A (Linear Technology)EVAL BOARD FOR LTC4278 PDF資料下載
參數(shù)資料
| 型號： | DC1561A |
| 廠商： | Linear Technology |
| 文件頁數(shù)： | 28/42頁 |
| 文件大小： | 0K |
| 描述： | EVAL BOARD FOR LTC4278 |
| 設(shè)計資源： | DC1561A Design Files |
| 標(biāo)準(zhǔn)包裝： | 1 |
| 主要目的： | 電源管理，以太網(wǎng)供電（POE） |
| 嵌入式： | 否 |
| 已用 IC / 零件： | LTC4278 |
| 已供物品： | 板 |
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頁當(dāng)前第28頁第29頁第30頁第31頁第32頁第33頁第34頁第35頁第36頁第37頁第38頁第39頁第40頁第41頁第42頁
LTC4278
34
4278fc
design evaluates the switcher for short-circuit protection
and adds any additional circuitry to prevent destruction.
Output Voltage Error Sources
The LTC4278’s feedback sensing introduces additional
minor sources of errors. The following is a summary list:
Theinternalbandgapvoltagereferencesetsthereference
voltage for the feedback amplifier. The specifications
detail its variation.
The external feedback resistive divider ratio directly
affects regulated voltage. Use 1% components.
Leakage inductance on the transformer secondary
reduces the effective secondary-to-feedback winding
turns ratio (NS/NF) from its ideal value. This increases
the output voltage target by a similar percentage. Since
secondary leakage inductance is constant from part to
part (within a tolerance) adjust the feedback resistor
ratio to compensate.
The transformer secondary current flows through the
impedances of the winding resistance, synchronous
MOSFET RDS(ON) and output capacitor ESR. The DC
equivalent current for these errors is higher than the
load current because conduction occurs only during
the converter’s off-time. So, divide the load current by
(1 – DC).
Iftheoutputloadcurrentisrelativelyconstant,thefeedback
resistive divider is used to compensate for these losses.
Otherwise, use the LTC4278 load compensation circuitry
(see Load Compensation). If multiple output windings are
used, the flyback winding will have a signal that represents
an amalgamation of all these windings impedances. Take
carethatyouexamineworst-caseloadingconditionswhen
tweaking the voltages.
Power MOSFET Selection
ThepowerMOSFETsareselectedprimarilyonthecriteriaof
on-resistance RDS(ON),inputcapacitance,drain-to-source
breakdown voltage (BVDSS), maximum gate voltage (VGS)
and maximum drain current (ID(MAX)).
For the primary-side power MOSFET, the peak current is:
IPK(PRI) =
PIN
VIN(MIN) DCMAX
1+ XMIN
2
APPLICATIONS INFORMATION
where XMINispeak-to-peakcurrentratioasdefinedearlier.
For each secondary-side power MOSFET, the peak cur-
rent is:
IPK(SEC) =
IOUT
1DCMAX
1+ XMIN
2
Select a primary-side power MOSFET with a BVDSS
greater than:
BVDSS ≥IPK
LLKG
CP
+ VIN(MAX) +
VOUT(MAX)
NSP
where NSP reflects the turns ratio of that secondary-to
primary winding. LLKG is the primary-side leakage induc-
tanceandCPistheprimary-sidecapacitance(mostlyfrom
the drain capacitance (COSS) of the primary-side power
MOSFET). A clamp may be added to reduce the leakage
inductance as discussed.
Foreachsecondary-sidepowerMOSFET,theBVDSSshould
be greater than:
BVDSS ≥ VOUT + VIN(MAX) NSP
Choose the primary-side MOSFET RDS(ON) at the nominal
gatedrivevoltage(7.5V).Thesecondary-sideMOSFETgate
drive voltage depends on the gate drive method.
Primary-side power MOSFET RMS current is given by:
IRMS(PRI) =
PIN
VIN(MIN) DCMAX
For each secondary-side power MOSFET RMS current is
given by:
IRMS(SEC) =
IOUT
1– DCMAX
Calculate MOSFET power dissipation next. Because the
primary-side power MOSFET operates at high VDS, a
transitionpowerlosstermisincludedforaccuracy.CMILLER
is the most critical parameter in determining the transition
loss, but is not directly specified on the data sheets.
相關(guān)PDF資料 |
PDF描述 |
|---|---|
| VE-B32-EW | CONVERTER MOD DC/DC 15V 100W |
| H3AAH-6406M | IDC CABLE - HSC64H/AE64M/HSC64H |
| L-07C43NKV6T | CER INDUCTOR 43NH 0402 |
| EBC22DREI-S13 | CONN EDGECARD 44POS .100 EXTEND |
| ECO-S1EA562BA | CAP ALUM 5600UF 25V 20% SNAP |
相關(guān)代理商/技術(shù)參數(shù) |
參數(shù)描述 |
|---|---|
| DC1561B | 功能描述:EVAL BOARD FOR LTC4278 RoHS:是 類別:編程器，開發(fā)系統(tǒng) >> 評估演示板和套件 系列:- 標(biāo)準(zhǔn)包裝:1 系列:- 主要目的:數(shù)字電位器 嵌入式:- 已用 IC / 零件:AD5258 主要屬性:- 次要屬性:- 已供物品:板 相關(guān)產(chǎn)品:AD5258BRMZ1-ND - IC POT DGTL I2C1K 64P 10MSOPAD5258BRMZ10-ND - IC POT DGTL I2C 10K 64P 10MSOPAD5258BRMZ100-ND - IC POT DGTL I2C 100K 64P 10MSOPAD5258BRMZ50-ND - IC POT DGTL I2C 50K 64P 10MSOPAD5258BRMZ1-R7-ND - IC POT DGTL I2C 1K 64P 10MSOPAD5258BRMZ10-R7-ND - IC POT DGTL I2C 10K 64P 10MSOPAD5258BRMZ50-R7-ND - IC POT DGTL I2C 50K 64P 10MSOPAD5258BRMZ100-R7-ND - IC POT DGTL I2C 100K 64P 10MSOP |
| DC1561W | 制造商:Aleph America Corporation 功能描述: |
| DC1561W-COM | 制造商:Aleph America Corporation 功能描述: |
| DC1562A-A | 功能描述:BOARD EVAL LTC6990 RoHS:是 類別:編程器，開發(fā)系統(tǒng) >> 評估演示板和套件 系列:TimerBlox® 標(biāo)準(zhǔn)包裝:1 系列:- 主要目的:電信，線路接口單元（LIU） 嵌入式:- 已用 IC / 零件:IDT82V2081 主要屬性:T1/J1/E1 LIU 次要屬性:- 已供物品:板，電源，線纜，CD 其它名稱:82EBV2081 |
| DC1562A-B | 功能描述:BOARD EVAL LTC6991 RoHS:是 類別:編程器，開發(fā)系統(tǒng) >> 評估演示板和套件 系列:TimerBlox® 標(biāo)準(zhǔn)包裝:1 系列:- 主要目的:電信，線路接口單元（LIU） 嵌入式:- 已用 IC / 零件:IDT82V2081 主要屬性:T1/J1/E1 LIU 次要屬性:- 已供物品:板，電源，線纜，CD 其它名稱:82EBV2081 |
發(fā)布緊急采購，3分鐘左右您將得到回復(fù)。