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參數(shù)資料
| 型號(hào)： | LM3310 |
| 廠商： | National Semiconductor Corporation |
| 英文描述： | Step-up PWM DC/DC Converter with Integrated Op-Amp and Gate Pulse Modulation Switch |
| 中文描述： | 升壓PWM直流/直流轉(zhuǎn)換器集成的運(yùn)算放大器和脈沖調(diào)制開關(guān)門 |
| 文件頁數(shù)： | 14/25頁 |
| 文件大?。?/td> | 1668K |
| 代理商： | LM3310 |
Operation
CONTINUOUS CONDUCTION MODE
The LM3310 contains a current-mode, PWM boost regulator.
A boost regulator steps the input voltage up to a higher
output voltage. In continuous conduction mode (when the
inductor current never reaches zero at steady state), the
boost regulator operates in two cycles.
In the first cycle of operation, shown in
Figure 1
(a), the
transistor is closed and the diode is reverse biased. Energy
is collected in the inductor and the load current is supplied by
C
OUT
.
The second cycle is shown in
Figure 1
(b). During this cycle,
the transistor is open and the diode is forward biased. The
energy stored in the inductor is transferred to the load and
output capacitor.
The ratio of these two cycles determines the output voltage.
The output voltage is defined approximately as:
where D is the duty cycle of the switch, D and D' will be
required for design calculations.
SETTING THE OUTPUT VOLTAGE (BOOST
CONVERTER)
The output voltage is set using the feedback pin and a
resistor divider connected to the output as shown in the
typical operating circuit. The feedback pin voltage is 1.263V,
so the ratio of the feedback resistors sets the output voltage
according to the following equation:
SOFT-START CAPACITOR
The LM3310 has a soft-start pin that can be used to limit the
inductor inrush current on start-up. The external SS pin is
used to tailor the soft-start for a specific application but is not
required for all applications and can be left open when not
needed. When used a current source charges the external
soft-start capacitor C
until it reaches its typical clamp
voltage, V
SS
. The soft-start time can be estimated as:
T
SS
= C
SS
*V
SS
/I
SS
THERMAL SHUTDOWN
The LM3310 includes thermal shutdown. If the die tempera-
ture reaches 145C the device will shut down until it cools to
a safe temperature at which point the device will resume
operation. If the adverse condition that is heating the device
is not removed (ambient temperature too high, short circuit
conditions, etc...) the device will continue to cycle on and off
to keep the die temperature below 145C. The thermal shut-
down has approximately 20C of hysteresis. When in ther-
mal shutdown the boost regulator, Op-Amp, and GPM blocks
will all be disabled.
INPUT UNDER-VOLTAGE PROTECTION
The LM3310 includes input under-voltage protection (UVP).
The purpose of the UVP is to protect the device both during
start-up and during normal operation from trying to operate
with insufficient input voltage. During start-up using a ramp-
ing input voltage the UVP circuitry ensures that the device
20133302
FIGURE 1. Simplified Boost Converter Diagram
(a) First Cycle of Operation (b) Second Cycle Of Operation
L
www.national.com
14
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| LM3310SQ | Step-up PWM DC/DC Converter with Integrated Op-Amp and Gate Pulse Modulation Switch |
| LM3310SQX | Step-up PWM DC/DC Converter with Integrated Op-Amp and Gate Pulse Modulation Switch |
| LM3351 | Switched Capacitor Voltage Converter |
| LM3351MM | Switched Capacitor Voltage Converter |
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相關(guān)代理商/技術(shù)參數(shù) |
參數(shù)描述 |
|---|---|
| LM3310_07 | 制造商:NSC 制造商全稱:National Semiconductor 功能描述:Step-Up PWM DC/DC Converter with Integrated Op-Amp and Gate Pulse Modulation Switch |
| LM3310SQ | 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 |
| LM3310SQ/NOPB | 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 |
| LM3310SQX | 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 |
| LM3310SQX/NOPB | 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 |
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