參數(shù)資料
型號: LM2733
廠商: National Semiconductor Corporation
英文描述: 0.6/1.6 MHz Boost Converters With 40V Internal FET
中文描述: 0.6/1.6兆赫40V的升壓轉(zhuǎn)換器內(nèi)部場效應(yīng)管
文件頁數(shù): 11/13頁
文件大?。?/td> 507K
代理商: LM2733
Application Hints
(Continued)
MAXIMUM SWITCH CURRENT
The maximum FET swtch current available before the cur-
rent limiter cuts in is dependent on duty cycle of the appli-
cation. This is illustrated in the graphs below which show
both the typical and guaranteed values of switch current for
both the "X" and "Y" versions as a function of effective
(actual) duty cycle:
20055425
Switch Current Limit vs Duty Cycle - "X"
20055426
Switch Current Limit vs Duty Cycle - "Y"
CALCULATING LOAD CURRENT
As shown in the figure which depicts inductor current, the
load current is related to the average inductor current by the
relation:
I
LOAD
= I
IND
(AVG) x (1 - DC)
Where "DC" is the duty cycle of the application. The switch
current can be found by:
I
SW
= I
IND
(AVG) +
1
2
(I
RIPPLE
)
Inductor ripple current is dependent on inductance, duty
cycle, input voltage and frequency:
I
RIPPLE
= DC x (V
IN
-V
SW
) / (f x L)
combining all terms, we can develop an expression which
allows the maximum available load current to be calculated:
The equation shown to calculate maximum load current
takes into account the losses in the inductor or turn-OFF
switching losses of the FET and diode. For actual load
current in typical applications, we took bench data for vari-
ous input and output voltages for both the "X" and "Y"
versions of the LM2733 and displayed the maximum load
current available for a typical device in graph form:
20055434
Max. Load Current vs V
IN
- "X"
20055433
Max. Load Current vs V
IN
- "Y"
DESIGN PARAMETERS V
SW
AND I
SW
The value of the FET "ON" voltage (referred to as V
in the
equations) is dependent on load current. A good approxima-
tion can be obtained by multiplying the "ON Resistance" of
the FET times the average inductor current.
FET on resistance increases at V
values below 5V, since
the internal N-FET has less gate voltage in this input voltage
range (see Typical performance Characteristics curves).
Above V
IN
= 5V, the FET gate voltage is internally clamped
to 5V.
L
www.national.com
11
相關(guān)PDF資料
PDF描述
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LM2734XMK Thin SOT23 1A Load Step-Down DC-DC Regulator
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相關(guān)代理商/技術(shù)參數(shù)
參數(shù)描述
LM2733_07 制造商:NSC 制造商全稱:National Semiconductor 功能描述:0.6/1.6 MHz Boost Converters With 40V Internal FET Switch in SOT-23
LM2733XEVAL 功能描述:BOARD EVALUATION LM2733X RoHS:否 類別:編程器,開發(fā)系統(tǒng) >> 評估板 - DC/DC 與 AC/DC(離線)SMPS 系列:PowerWise® 標(biāo)準(zhǔn)包裝:1 系列:- 主要目的:DC/DC,步降 輸出及類型:1,非隔離 功率 - 輸出:- 輸出電壓:3.3V 電流 - 輸出:3A 輸入電壓:4.5 V ~ 28 V 穩(wěn)壓器拓?fù)浣Y(jié)構(gòu):降壓 頻率 - 開關(guān):250kHz 板類型:完全填充 已供物品:板 已用 IC / 零件:L7981 其它名稱:497-12113STEVAL-ISA094V1-ND
LM2733XEVAL/NOPB 功能描述:電源管理IC開發(fā)工具 LM2733X EVAL BOARD RoHS:否 制造商:Maxim Integrated 產(chǎn)品:Evaluation Kits 類型:Battery Management 工具用于評估:MAX17710GB 輸入電壓: 輸出電壓:1.8 V
LM2733XMF 功能描述:DC/DC 開關(guān)控制器 RoHS:否 制造商:Texas Instruments 輸入電壓:6 V to 100 V 開關(guān)頻率: 輸出電壓:1.215 V to 80 V 輸出電流:3.5 A 輸出端數(shù)量:1 最大工作溫度:+ 125 C 安裝風(fēng)格: 封裝 / 箱體:CPAK
LM2733XMF/MEY8 制造商:Texas Instruments 功能描述: