本帖最後由 kamcm 於 2013-10-4 11:31 編輯
用IGBT得唔得，手上有啲25A IGBT剩下
avdaemon 發表於 2013-10-3 22:36 
問左廠家
zhouping_1984sz (08:30:31):
Current < 60A Ron > 50mR
zhouping_1984sz (08:31:12):
電流太大或者導通電阻太小的話，大多是用於開關模式，不適合做線性調節應用
kamcm (08:31:35):
是不是只要符合上面這2個參數就可以了
zhouping_1984sz (08:32:17):
這個只是初步刪選，實際能否使用要測試過後才行
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我又睇左D資料...
Power MOSFETs are most often used in switchedmode applications where they function as onoff switches. But in applications like electronic loads, linear regulators or Class A amplifi , power MOSFETs must operate in their linear region. In this operating mode, the MOSFETs are subjected to high thermal stress due to the simultaneous occurrence of high drain voltage and current, resulting in high power dissipation.
When the thermo-electrical stress exceeds some critical limit, thermal hot spots occur in the silicon causing the
devices to fail. To prevent such failure, MOSFETs operating in the linear region require high power dissipation capability and an extended forward-bias safe operating area (FBSOA).
A series of linear power MOSFETs developed by IXYS achieves an extended FBSOA capability by suppressing the
positive feedback of electro-thermal instability. The design of these new MOSFETs features a nonuniform distribution of transistor cells, as well as cells with different threshold voltages.
Every transistor cell is designed with a ballast resistor at the source to limit its current. The parasitic bipolar junction transistor (BJT) of each cell is heavily bypassed so that it will not turn on under extreme electrical stress conditions.
In addition, the thermal response of each power MOSFET is tested to assure no solder voids. The linear MOSFET’s effectiveness can be demonstrated in the design of an electronic load developed for power-supply testing.
REF: http://www.ixys.com/Documents/Ar ... r_Power_MOSFETs.pdf
Choosing the right MOSFET for linear mode operation
As discussed in section 1 linear mode operation will operate the MOSFET at high VDS and IDS simultaneously. Consequently, power dissipation will be high. The SOA diagram is a tool to evaluate the suitability of the MOSFET operation in linear mode.
In section 2 the various limit-lines of the SOA have been discussed and formulas have been presented that allow for recalculation of the SOA diagram for various application conditions. These equations also enable the deduction of some general rules for selecting the best suited MOSFET for linear mode operation.
At first it is important to understand whether the MOSFET will be operated continuously in linear mode (e.g. current source) or the MOSFET passes the linear mode operation region for a period of time before it is fully turned on.
• Continuous operation in linear mode
In case of continuous operation in linear mode the MOSFET’s RDS(on) and dynamic parameters are
irrelevant to judge power dissipation but the SOA is the key design criterium to the power engineer.
Thermal design is most important and therefore MOSFETS with low ZthJC are most suitable. To remove the
generated heat an appropriate package and cooling concept must be applied. Thermal instability can be avoided by utilizing MOSFETs with low ZTC point.This means that MOSFETs of previous technology
generations and/or higher voltage classes will be more suitable for this kind of application.
• Limited operation time in linear mode
The MOSFET will pass the linear mode operation region for a given period of time. The applied VDS voltage,
the IDS current and the pulse length must be known to understand if the MOSFET can handle the generated
power. It has to be verified that the MOSFET is being operated within the SOA. If the application conditions
differ from the SOA datasheet conditions (Tc temperature, VGS voltage, duty cycle …) the SOA diagram
needs to be recalculated according to the formulas given in section 2. Generally, a MOSFET with low ZthJC and very low RDS(on) will be a suitable product in cases where linear mode operation ruggedness is needed.
http://www.infineon.com/dgdl/Inf ... 4bf013e3646e9381200
Ching 如果試完冇問題記得話我知 
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Btw, EBD-A 只要做好散熱, 100W 負載不是問題...
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發表於 2013-10-3 22:34
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。劣質火牛整壞負載儀的ＭＯＳ 的機率高嗎？
發表於 2013-10-4 10:44
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