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參數(shù)資料
| 型號： | MIC4722 |
| 廠商： | Micrel Semiconductor,Inc. |
| 英文描述： | 3mm x 3mm 2.7MHz 3A PWM Buck Regulator |
| 中文描述： | 采用3mm x 3mm 2.7兆赫3A PWM降壓調(diào)節(jié) |
| 文件頁數(shù)： | 9/20頁 |
| 文件大?。?/td> | 581K |
| 代理商： | MIC4722 |
Micrel, Inc.
MIC4722
Application Information
The MIC4722 is a 3A PWM non-synchronous buck
regulator. By switching an input voltage supply, and
filtering the switched voltage through an Inductor and
capacitor, a regulated DC voltage is obtained. Figure 1
shows a simplified example of a non-synchronous buck
converter.
September 2007
9
M9999-090507-B
Figure 1. Example of non-synchronous buck converter
For a non-synchronous buck converter, there are two
modes of operation; continuous and discontinuous.
Continuous or discontinuous refer to the inductor
current. If current is continuously flowing through the
inductor throughout the switching cycle, it is in
continuous operation. If the inductor current drops to
zero during the off time, it is in discontinuous operation.
Critically continuous is the point where any decrease in
output current will cause it to enter discontinuous
operation. The critically continuous load current can be
calculated as follows;
=
L
2
2.7MHz
V
V
V
I
IN
×
2
OUT
OUT
OUT
×
Continuous or discontinuous operation determines how
we calculate peak inductor current.
Continuous Operation
Figure 2 illustrates the switch voltage and inductor
current during continuous operation.
Figure 2. Continuous Operation
The output voltage is regulated by pulse width
modulating (PWM) the switch voltage to the average
required output voltage. The switching can be broken up
into two cycles; On and Off.
During the on-time,
the high side switch is turned on,
current flows from the input supply through the inductor
and to the output. The inductor current is
Figure 3. On-Time
charged at the rate;
(
V
)
L
V
OUT
IN
To determine the total on-time, or time at which the
inductor charges, the duty cycle needs to be calculated.
The duty cycle can be calculated as;
IN
OUT
V
V
D
=
and the On time is;
2.7MHz
D
T
ON
=
Therefore, peak to peak ripple current is;
(
)
L
2.7MHz
V
V
V
V
I
IN
OUT
OUT
IN
pk
pk
×
×
=
Since the average peak to peak current is equal to the
load current. The actual peak (or highest current the
inductor will see in a steady state condition) is equal to
the output current plus the peak-to-peak current.
(
)
L
2.7MHz
2
V
V
V
V
I
I
IN
OUT
OUT
IN
OUT
pk
×
×
×
+
=
Figure 4 demonstrates the off-time. During the off-time,
the high-side internal P-channel MOSFET turns off.
Since the current in the inductor has to discharge, the
current flows through the free-wheeling Schottky diode
to the output. In this case, the inductor discharge rate is
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相關(guān)代理商/技術(shù)參數(shù) |
參數(shù)描述 |
|---|---|
| MIC4722_10 | 制造商:MICREL 制造商全稱:Micrel Semiconductor 功能描述:3mm x 3mm 2.7MHz 3A PWM Buck Regulator |
| MIC4722YML | 制造商:Rochester Electronics LLC 功能描述: 制造商:RF Micro Devices Inc 功能描述: |
| MIC4722YML TR | 功能描述:直流/直流開關(guān)調(diào)節(jié)器 3mm X 3mm 2.7MHz 3A PWM Buck Regulator RoHS:否 制造商:International Rectifier 最大輸入電壓:21 V 開關(guān)頻率:1.5 MHz 輸出電壓:0.5 V to 0.86 V 輸出電流:4 A 輸出端數(shù)量: 最大工作溫度: 安裝風(fēng)格:SMD/SMT 封裝 / 箱體:PQFN 4 x 5 |
| MIC4722YML-TR | 功能描述:Buck Switching Regulator IC Positive Adjustable 1V 1 Output 3A 12-VFDFN Exposed Pad, 12-MLF? 制造商:microchip technology 系列:- 包裝:剪切帶（CT） 零件狀態(tài):停產(chǎn) 功能:降壓 輸出配置:正 拓?fù)?降壓 輸出類型:可調(diào)式 輸出數(shù):1 電壓 - 輸入（最小值）:2.7V 電壓 - 輸入（最大值）:5.5V 電壓 - 輸出（最小值/固定）:1V 電壓 - 輸出（最大值）:5.5V 電流 - 輸出:3A 頻率 - 開關(guān):2.7MHz 同步整流器:無 工作溫度:-40°C ~ 125°C （TJ） 安裝類型:表面貼裝 封裝/外殼:12-VFDFN 裸焊盤，12-MLF? 供應(yīng)商器件封裝:12-MLF?（4x4） 標(biāo)準(zhǔn)包裝:1 |
| MIC4723 | 制造商:MICREL 制造商全稱:Micrel Semiconductor 功能描述:3A 2MHz Integrated Switch Buck Regulator |
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