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HV100_07 参数 Datasheet PDF下载

HV100_07图片预览
型号: HV100_07
PDF下载: 下载PDF文件 查看货源
内容描述: 3针热插拔,浪涌电流限幅控制器(负电源轨) [3-Pin Hotswap, Inrush Current Limiter Controllers (Negative Supply Rail)]
分类和应用: 控制器
文件页数/大小: 8 页 / 592 K
品牌: SUPERTEX [ Supertex, Inc ]
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HV100/HV101  
All of the above are possible with a minimum number of ex-  
ternal components.  
Auto-Retry  
Not only do the HV±11 and HV±1± provide short circuit pro-  
tection in a 3-pin package, they also includes a 2.5s built in  
auto-restart timer. The HV±11 and HV±1± will continuously  
try to turn on the system every 2.5s, providing sufficient time  
for the pass element to cool down after each attempt.  
i) To adjust inrush current with an external component  
simply connect a capacitor (C ) from drain to gate of the  
MOSFET. The inrush calculatFioB n then becomes:  
ꢁNRUSH(PEAK) = (CFB + CꢁSS)/(CRSS + CFB) * 2.5e3 * CLOAD  
Note that a resistor (approximately ±1KΩ) needs to be  
added in series with CFB to create a zero in the feedback  
loop and limit the spurious turn on which is now enhanced  
by the larger divider element.  
ii) To increase undervoltage lockout simply connect a Zener  
diode in series with the VPP pin.  
iii) ꢁf the VPP rises particularly fast (>48e6V/s) then it may  
be desirable to connect a capacitor from gate to source  
of the MOSFET to provide a path for the power applica-  
tion transient spike, which is now too fast for the internal  
clamping mechanism.  
iv) To limit the peak current during a short circuit, a resistor  
in series with the source of the MOSFET may help.  
Calculating Inrush Current  
As can be seen in the diagram below, for a standard pass  
element, the HV±11 and HV±1± will normalize the hotswap  
time period against load capacitance. For this reason the  
current limit will increase with increasing value of the load  
capacitance.  
Implementing PWRGD Control  
Due to the HV±11 and HV±1±’s small footprint, it is possible  
to create an open drain PWRGD signal using external com-  
ponents and still maintain a size comparable with the smallest  
hotswapcontrollersavailableelsewhere.Toaccomplishthisan  
external MOSFET may be used in conjunction with the gate  
output. Simply use a high impedance divider (±1MΩ) sized  
so that the open drain PWRGD MOSFET threshold will only  
be reached once the HV±11/HV±1±’s gate voltage rises well  
abovethecurrentlimitvaluerequiredbytheexternalMOSFET  
pass device. Alternatively a Zener diode between the gate  
output and the PWRGD MOSFET gate set at a voltage higher  
than the maximum pass element Vt will also work.  
ꢁnrush can be calculated from the following formula:  
ꢁNRUSH(PEAK) = (CꢁSS / CRSS) * 2.5e3 * CLOAD  
This is a surprisingly consistent result because for most MOS-  
FETs of a particular type the ratio of CꢁSS / CRSS is relatively  
constant (though notice from the plot that there is some varia-  
tion) even while the absolute value of these and other quanti-  
ties vary. Based on this, the inrush current will vary primarily  
with CLOAD. This makes designing with the HV±11 and HV±1±  
particularly easy because once the pass element is chosen,  
the period is fixed and the inrush varies with CLOAD only.  
HV100  
Programming the HV100 and HV101  
The HV±11 and HV±1± require no external components other  
than a pass element to provide the functionality described  
thus far. ꢁn some applications it may be useful to use external  
components to adjust the maximum allowable inrush current,  
adjust UVLO, or to provide additional gate clamping if the  
supply rails have rise times below ±ms.  
PWGRD  
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