- 您現(xiàn)在的位置：買賣IC網(wǎng) > PDF目錄384734 > MIC2171 (Micrel Semiconductor,Inc.) Isolated Flyback Switching Regulator with 9V Output PDF資料下載
參數(shù)資料
| 型號： | MIC2171 |
| 廠商： | Micrel Semiconductor,Inc. |
| 元件分類： | 基準電壓源/電流源 |
| 英文描述： | Isolated Flyback Switching Regulator with 9V Output |
| 中文描述： | 隔離反激式開關(guān)穩(wěn)壓9V輸出 |
| 文件頁數(shù)： | 10/10頁 |
| 文件大小： | 80K |
| 代理商： | MIC2171 |
MIC2171
Micrel
4-12
1997
D3
1N5819
MIC2171
IN
SW
FB
COMP
C1
22μF
C3
1μF
R2
1k
V
OUT
5V, 1A
R4
3.74k
1%
R5
1.24k
1%
C5
470μF
L1 100μH
V
IN
12V
GND
T1
1:1:1
D4
1N5819
D2
1N5819
* Voltage clipper
Duty cycle limiter
D1*
C2*
Q1
C4
R3
R1*
Figure 7. MIC2171 Forward Converter
Forward Converters
Micrel’s MIC2171 can be used in several circuit configura-
tions to generate an output voltage which is less than the input
voltage (buck or step-down topology). Figure 7 shows the
MIC2171 in a voltage step-down application. Because of the
internal architecture of these devices, more external compo-
nents are required to implement a step-down regulator than
with other devices offered by Micrel (refer to the LM257x or
MIC457x family of buck switchers). However, for step-down
conversion requiring a transformer (forward), the MIC2171 is
a good choice.
A 12V to 5V step-down converter using transformer isolation
(forward) is shown in Figure 7. Unlike the isolated flyback
converter which stores energy in the primary inductance
during the controller’s on-time and releases it to the load
during the off-time, the forward converter transfers energy to
the output during the on-time, using the off-time to reset the
transformer core. In the application shown, the transformer
core is reset by the tertiary winding discharging T1’s peak
magnetizing current through D2.
For most forward converters the duty cycle is limited to 50%,
allowing the transformer flux to reset with only two times the
input voltage appearing across the power switch. Although
during normal operation this circuit’s duty cycle is well below
50%, the MIC2172 has a maximum duty cycle capability of
90%. If 90% was required during operation (start-up and high
load currents), a complete reset of the transformer during the
off-time would require the voltage across the power switch to
be ten times the input voltage. This would limit the input
voltage to 6V or less for forward converter applications.
To prevent core saturation, the application given here uses a
duty cycle limiter consisting of Q1, C4 and R3. Whenever the
MIC2171 exceeds a duty cycle of 50%, T1’s reset winding
current turns Q1 on. This action reduces the duty cycle of the
MIC2171 until T1 is able to reset during each cycle.
相關(guān)PDF資料 |
PDF描述 |
|---|---|
| MIC2185 | Low Voltage Synchronous Boost PWM Control IC |
| MIC2185BM | Low Voltage Synchronous Boost PWM Control IC |
| MIC2185BQS | Low Voltage Synchronous Boost PWM Control IC |
| MIC2193 | 400KHZ SO 8 SYNCHRONOUS BUCK CONTROL IC |
| MIC2193BM | 400KHZ SO 8 SYNCHRONOUS BUCK CONTROL IC |
相關(guān)代理商/技術(shù)參數(shù) |
參數(shù)描述 |
|---|---|
| MIC2171_07 | 制造商:MICREL 制造商全稱:Micrel Semiconductor 功能描述:100kHz 2.5A Switching Regulator |
| MIC2171BT | 功能描述:IC REG MULTI CONFIG 2.5A TO220-5 RoHS:否 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 |
| MIC2171BTL3 | 制造商:RF Micro Devices Inc 功能描述: |
| MIC2171BU | 功能描述:IC REG MULTI CONFIG 2.5A TO263-5 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 |
| MIC2171BU TR | 功能描述:IC REG MULTI CONFIG 2.5A TO263-5 RoHS:否 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 |
發(fā)布緊急采購，3分鐘左右您將得到回復(fù)。