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參數(shù)資料
| 型號(hào)： | NCV8842 |
| 廠商： | ON SEMICONDUCTOR |
| 英文描述： | 1.5 A, 170 kHz, Buck Regulator with Synchronization Capability |
| 中文描述： | 1.5甲，170千赫，降壓穩(wěn)壓器的同步功能 |
| 文件頁(yè)數(shù)： | 7/15頁(yè) |
| 文件大?。?/td> | 186K |
| 代理商： | NCV8842 |
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NCV8842
http://onsemi.com
7
duty cycle of the sync pulses can vary from 10% to 90%. The
frequency foldback feature is disabled during the sync
mode.
Figure 4. A NCV8842 Buck Regulator is Synchronized
to an External 350 kHz Pulse Signal
Power Switch and Current Limit
The collector of the builtin NPN power switch is
connected to the V
IN
pin, and the emitter to the V
SW
pin.
When the switch turns on, the V
SW
voltage is equal to the
V
IN
minus switch Saturation Voltage. In the buck regulator,
the V
SW
voltage swings to one diode drop below ground
when the power switch turns off, and the inductor current is
commutated to the catch diode. Due to the presence of high
pulsed current, the traces connecting the V
SW
pin, inductor
and diode should be kept as short as possible to minimize the
noise and radiation. For the same reason, the input capacitor
should be placed close to the V
IN
pin and the anode of the
diode.
The saturation voltage of the power switch is dependent
on the switching current, as shown in Figure 5.
Figure 5. The Saturation Voltage of the Power Switch
Increases with the Conducting Current
0
0.5
1.0
1.5
SWITCHING CURRENT (A)
V
I
S
0
0.1
0.2
0.3
0.4
0.5
0.6
0.7
The NCV8842 contains pulsebypulse current limiting
to protect the power switch and external components. When
the peak of the switching current reaches the Current Limit,
the power switch turns off after the Current Limit Delay. The
switch will not turn on until the next switching cycle. The
current limit threshold is independent of switching duty
cycle. The maximum load current, given by the following
formula under continuous conduction mode, is less than the
Current Limit due to the ripple current.
IO(MAX)
ILIM
VO(VIN
2(L)(VIN)(fs)
VO)
where:
f
S
= switching frequency,
I
LIM
= current limit threshold,
V
O
= output voltage,
V
IN
= input voltage,
L = inductor value.
When the regulator runs under current limit, the
subharmonic oscillation may cause low frequency
oscillation, as shown in Figure 6. Similar to current mode
control, this oscillation occurs at the duty cycle greater than
50% and can be alleviated by using a larger inductor value.
The current limit threshold is reduced to Foldback Current
when the FB pin falls below Foldback Threshold. This
feature protects the IC and external components under the
power up or overload conditions.
Figure 6. The Regulator in Current Limit
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| NCV8842MNR2G | 1.5 A, 170 kHz, Buck Regulator with Synchronization Capability |
| NCV8842PWG | 1.5 A, 170 kHz, Buck Regulator with Synchronization Capability |
| NCV8842PWR2G | 1.5 A, 170 kHz, Buck Regulator with Synchronization Capability |
| NCV8843MNR2G | 1.5 A, 340 kHz, Buck Regulator with Synchronization Capability |
| NCV8843PWG | 1.5 A, 340 kHz, Buck Regulator with Synchronization Capability |
相關(guān)代理商/技術(shù)參數(shù) |
參數(shù)描述 |
|---|---|
| NCV8842_11 | 制造商:ONSEMI 制造商全稱:ON Semiconductor 功能描述:1.5 A, 170 kHz, Buck Regulator with Synchronization Capability |
| NCV8842DG | 功能描述:直流/直流開(kāi)關(guān)轉(zhuǎn)換器 1.5A LOW VOLTAGE REG RoHS:否 制造商:STMicroelectronics 最大輸入電壓:4.5 V 開(kāi)關(guān)頻率:1.5 MHz 輸出電壓:4.6 V 輸出電流:250 mA 輸出端數(shù)量:2 最大工作溫度:+ 85 C 安裝風(fēng)格:SMD/SMT |
| NCV8842DR2G | 功能描述:直流/直流開(kāi)關(guān)轉(zhuǎn)換器 1.5A LOW VOLTAGE REG RoHS:否 制造商:STMicroelectronics 最大輸入電壓:4.5 V 開(kāi)關(guān)頻率:1.5 MHz 輸出電壓:4.6 V 輸出電流:250 mA 輸出端數(shù)量:2 最大工作溫度:+ 85 C 安裝風(fēng)格:SMD/SMT |
| NCV8842MNR2G | 功能描述:直流/直流開(kāi)關(guān)轉(zhuǎn)換器 1.5A LOW VOLTAGE BUCK REG RoHS:否 制造商:STMicroelectronics 最大輸入電壓:4.5 V 開(kāi)關(guān)頻率:1.5 MHz 輸出電壓:4.6 V 輸出電流:250 mA 輸出端數(shù)量:2 最大工作溫度:+ 85 C 安裝風(fēng)格:SMD/SMT |
| NCV8842MNR2GEVB | 功能描述:BOARD EVAL FOR NCV8842 RoHS:是 類(lèi)別:編程器，開(kāi)發(fā)系統(tǒng) >> 評(píng)估板 - DC/DC 與 AC/DC（離線）SMPS 系列:- 產(chǎn)品培訓(xùn)模塊:Obsolescence Mitigation Program 標(biāo)準(zhǔn)包裝:1 系列:True Shutdown™ 主要目的:DC/DC，步升 輸出及類(lèi)型:1，非隔離 功率 - 輸出:- 輸出電壓:- 電流 - 輸出:1A 輸入電壓:2.5 V ~ 5.5 V 穩(wěn)壓器拓?fù)浣Y(jié)構(gòu):升壓 頻率 - 開(kāi)關(guān):3MHz 板類(lèi)型:完全填充 已供物品:板 已用 IC / 零件:MAX8969 |
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