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參數(shù)資料
| 型號： | MIC4721YMM |
| 廠商： | MICREL INC |
| 元件分類： | 穩(wěn)壓器 |
| 英文描述： | Dual UART with 64-byte FIFO, SOT313-2 (LQFP48), Reel Pack, SMD, 13", Turned |
| 中文描述： | 11 A SWITCHING REGULATOR, 2200 kHz SWITCHING FREQ-MAX, PDSO10 |
| 封裝： | LEAD FREE, MSOP-10 |
| 文件頁數(shù)： | 9/19頁 |
| 文件大?。?/td> | 827K |
| 代理商： | MIC4721YMM |
Micrel, Inc.
MIC4721
Application Information
The MIC4721 is a 1.5A PWM non-synchronous buck
regulator. A regulated DC output voltage is obtained by
switching an input voltage supply, and filtering the
switched voltage through an inductor and capacitor.
Figure 1 shows a simplified example of a non-synch-
ronous buck converter and its input/output voltage.
May 2007
9
M9999-052907-A
Figure 1. Simplified Buck Converter
For a non-synchronous buck converter, there are two
modes of operation; continuous and discontinuous. The
mode refers to the state of current in the inductor. If
current
continuously
flows
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.
through
the
inductor
S
IN
OUT
V
OUT
V
CRITICAL
OUT
f
L
V
I
×
×
=
2
2
_
Where: f
S
is the switching frequency (2MHz for the
MIC4721).
L is the output inductance (Henry).
When I
OUT
is less than I
OUT_CRITICAL
, the buck converter
operates in discontinuous mode and the inductor current
goes to zero before the end of each switching cycle.
When I
OUT
is greater than I
OUT_CRITICAL
, the converter
operates in continuous mode and current always flows in
the inductor. Continuous or discontinuous operation
determines how peak inductor current is calculated.
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.
As seen in Figure 3, the high side switch is turned on
(on-time) and current flows from the input supply through
the inductor and to the output.
Figure 3. On-Time
The inductor current is charged at the rate:
(
)
L
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:
V
D
=
V
V
OUT
IN
IN
OUT
V
and the On time is:
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相關(guān)代理商/技術(shù)參數(shù) |
參數(shù)描述 |
|---|---|
| MIC4721YMM TR | 功能描述:直流/直流開關(guān)調(diào)節(jié)器 1.5A 2MHz 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 |
| MIC4721YMMTR | 功能描述:IC REG BUCK ADJ 1.5A 10MSOP RoHS:是 類別:集成電路 (IC) >> PMIC - 穩(wěn)壓器 - DC DC 開關(guān)穩(wěn)壓器 系列:- 標準包裝:20 系列:SIMPLE SWITCHER® 類型:降壓（降壓） 輸出類型:固定 輸出數(shù):1 輸出電壓:12V 輸入電壓:4 V ~ 60 V PWM 型:電壓模式 頻率 - 開關(guān):52kHz 電流 - 輸出:1A 同步整流器:無 工作溫度:-40°C ~ 125°C 安裝類型:通孔 封裝/外殼:16-DIP（0.300"，7.62mm） 包裝:管件 供應(yīng)商設(shè)備封裝:16-DIP 其它名稱:*LM2575HVN-12LM2575HVN-12 |
| MIC4722 | 制造商:MICREL 制造商全稱:Micrel Semiconductor 功能描述:3mm x 3mm 2.7MHz 3A PWM Buck Regulator |
| 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: |
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