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參數(shù)資料
| 型號(hào)： | LM3407 |
| 廠商： | National Semiconductor Corporation |
| 英文描述： | 350 mA, Constant Current Output Floating Buck Switching Converter for High Power LEDs |
| 中文描述： | 350毫安，恒流輸出浮點(diǎn)高功率LED的降壓開關(guān)轉(zhuǎn)換器 |
| 文件頁數(shù)： | 9/16頁 |
| 文件大?。?/td> | 321K |
| 代理商： | LM3407 |
30046620
FIGURE 2. LM3407 Switching Waveforms
The switching frequency and duty ratio of the converter equal:
By comparing the area of V
and V
over the ON period,
an error signal is generated. Such a comparison is function-
ally equivalent to comparing the middle level of I
to V
during the ON-period of a switching cycle. The error signal is
fed to a PWM comparator circuit to produce the PWM control
pulse to drive the internal power N-MOSFET.
Figure 3
shows
the implementation of the PWM switching signal. The error
signal is fed to a PWM comparator circuit to produce the PWM
control pulse to drive the internal power N-MOSFET.
Figure
3
shows the implementation of the PWM switching signal.
In closed loop operation, the difference between V
and
V
is reflected in the changes of the switching duty cycle of
the power switch. This behavior is independent of the induc-
tance of the inductor and input voltage because for the same
set of I
* R
ISNS
, ON time, and switching period, there exists
only one V
shows two sets of current sense sig-
nals named V
and V
that have identical frequencies
and duty cycles but different shapes of trapezoidal wave-
forms, each generating identical PWM signals.
30046623
FIGURE 3. Pulse-Level Transformation
When V
is higher than V
, the peak value of V
, the
switching duty cycle of the power switch will be reduced to
lower V
. When V
is lower than the peak value of V
,
the switching duty cycle of the power switch will be increased
to raise V
. For example, when I
is decreased, V
will
become lower than V
. In order to maintain output current
regulation, the switching duty cycle of the power switch will
be increased and eventually push up V
until V
MSL
equals
V
REF
. Since in typical floating buck regulators V
is equal
to I
* R
, true average output current regulation can be
achieved by regulating V
.
Figure 5
shows the waveforms
of V
ISNS
and V
RP
under closed loop operation.
9
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相關(guān)代理商/技術(shù)參數(shù) |
參數(shù)描述 |
|---|---|
| LM3407_09 | 制造商:NSC 制造商全稱:National Semiconductor 功能描述:350 mA, Constant Current Output Floating Buck Switching Converter for High Power LEDs |
| LM3407_11 | 制造商:TI 制造商全稱:Texas Instruments 功能描述:LM3407 350 mA, Constant Current Output Floating Buck Switching Converter |
| LM3407EVAL | 功能描述:BOARD EVALUATION FOR LM3407 RoHS:否 類別:編程器，開發(fā)系統(tǒng) >> 評估板 - LED 驅(qū)動(dòng)器 系列:PowerWise® 標(biāo)準(zhǔn)包裝:1 系列:PowerWise® 電流 - 輸出 / 通道:20mA 輸出及類型:1，非隔離 輸出電壓:17V 特點(diǎn):可調(diào)光 輸入電壓:2.7 ~ 5.5 V 已供物品:板 已用 IC / 零件:LM3508 相關(guān)產(chǎn)品:LM3508TLX-ND - IC LED DRVR WHT BCKLGT 9USMDLM3508TLDKR-ND - IC LED DRVR WHT BCKLGT 9MICROSMDLM3508TLCT-ND - IC LED DRVR WHT BCKLGT 9MICROSMDLM3508TLTR-ND - IC LED DRVR WHT BCKLGT 9MICROSMD |
| LM3407EVAL/NOPB | 功能描述:電源管理IC開發(fā)工具 LM3407 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 |
| LM3407MY | 制造商:Texas Instruments 功能描述:Conv DC-DC Single Step Down 4.5V to 30V 8-Pin MSOP EP T/R 制造商:Texas Instruments 功能描述:BUCK SW CONVERTER, 350MA, POWERWISE |
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