t******m
发帖数: 4 | 1 电路好象不是很难,关键是电流的测量,朋友告诉我用LEM的current transducer, 但我
觉得好象精度不够.比如我要测的SiC JFET, 开关时间在几十个纳秒,但是transducer反
应的时间要一个毫秒左右,waveform测出来应该误差很大吧...
本人绝对菜鸟,望达人不吝赐教. |
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t******m
发帖数: 4 | 2 sorry, a stupid mistake, it is 1us, not 1ms.
我想测的是SiC JFET bare chip的动态特性，实际就是开关波形（VI turn on/off
waveform)，只是文献上都是只给出简单的电路图，真正用来测电流瞬时变化的器件没
有特别说明我又没有这方面的经验，只能乱搞了。。
呢？ |
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t*f
发帖数: 114 | 3 你去search一下high voltage power MOSFET的测试方法和电路。甚至power BJT的测试
电路。
或者直接在google scholar上search SiC JFET switching。 |
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e***i
发帖数: 58 | 4 你可能需要一个高频的信号发生器和示波器吧？pulse generator, oscilloscope.
curve tracer 一般有pulse的源，但都是微秒的，好像是3 micron sec?或许
300 ns?我不记得了。不然curve tracer应该是便宜又方便。
因为SiC JFET都是作为高频高压开关，不知道功率有什么要求。 |
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发帖数: 1 | 5 FET我多數時候用在做電吉他效果器，做過一個JFET的RIAA preamp給我的Turntable用
的。
jFET可能是最接近電子管的晶體管了。不過，若要不失真電壓要比較高。沒記錯的好像
是用18-24V。
玩這些東西玩進去了花再多錢買的都不如自己親手做的。就像綁Fly一樣。
今年冬天我有個Project，想試試看做個低瓦數的single ended Stereo功放。 |
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s**g
发帖数: 66 | 6 Thank you for sharing.Your discussion is very informing.
I'd like to make a few comments:
1. is MP0 a JFET? If so, the device symbol you drew is incorrect.
2. Almost all band gap start up ckt can be properly simulated. That is, you
shall be able to predict if the ckt could latch up to off-condition. Keep in
mind start up problem is essentially a DC operating point problem, not a
transient issue.I guess you either use transient sim or power supply DC
sweep to verify your design, which is not the ... 阅读全帖 |
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s**g
发帖数: 66 | 7 Thank you for sharing.Your discussion is very informing.
I'd like to make a few comments:
1. is MP0 a JFET? If so, the device symbol you drew is incorrect.
2. Almost all band gap start up ckt can be properly simulated. That is, you
shall be able to predict if the ckt could latch up to off-condition. Keep in
mind start up problem is essentially a DC operating point problem, not a
transient issue.I guess you either use transient sim or power supply DC
sweep to verify your design, which is not the ... 阅读全帖 |
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E**O
发帖数: 1980 | 8 mmz贴得是关于LED方面的产品，我贴的是被大多数人忽略的Slicon Carbide (SiC)
Diode。再贴一篇：
SiC Schottky diode demand takes off in 2009
Wednesday, April 28, 2010
By Gina Roos
imsresearchlogoWellingborough, U.K. — The silicon carbide (SiC) Schottky
diode market grew 25 percent in 2009, compared to the previous year,
reaching an estimated $29 million, reports IMS Research. Growth fell in line
with the total power semiconductor market during the downturn, but
experienced strong demand in the second half of 2009, according to th... 阅读全帖 |
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w***u
发帖数: 17713 | 9 产业越靠后，或者越靠近钱越有钱。
想想吧，你们也就是明白JFET的大致道理，会个滤波，S-domain frequency domain啥
的。想想你们的前端，人家做出那么小的陶瓷电容，多少个才一块钱？里面的原理和工
艺积累不比拉普拉斯变换需要的少。你们用的小8bit mpu之类的，人家工厂出厂价才几
美分，钱都一般难赚，不幸的是生在更能批量生产的前端，比如采矿。
一样一样，看看人家金融，绝大部分funds都不能beat s&p 500，人家那工资拿得多爽
？ |
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发帖数: 1 | 10 Please send your resume directly to the company HR Specialist:
[email protected]/* */
Location: San Jose, CA, USA
Company: Hermes Microvision Inc. An ASML Company
The company sponsors H1B and provides relocation assistance.
Job title: Sr. Electrical Engineer
Job Descriptions:
Join the development of all the circuits in both board level and IC level,
and sub-system in HMI e-beam wafer inspection tools. The position is focused
on analog and mixed signal circuit design and circuit simul... 阅读全帖 |
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m********u
发帖数: 3942 | 11 地点San Jose, CA
DESCRIPTION
Join the development of all the circuits in both board level and IC level,
and sub-system in HMI e-beam wafer inspection tools. The position is focused
on analog and mixed signal circuit design and circuit simulation in both
board level and IC level, print circuit board (PCB) layout, PCB prototyping,
tuning and debugging, ASIC tapeout, pilot production, and technical
document writing. The position may be involved in but not limited to the
design works listed as follows... 阅读全帖 |
|
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b*****e
发帖数: 5133 | 13 泥坑如果有份早就吹上天了，记得D2H那个什么什么JFET LBCAST吗？ |
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发帖数: 1 | 14 Silicon Carbide: Smaller, Faster, Tougher
Meet the material that will supplant silicon in hybrid cars and the electric
grid
Illustration: Anatomy Blue
Some technological revolutions are flashy, and some are almost invisible. We
’re quite familiar with the flashy ones; they’ve given us powerful
computers we can hold in the palms of our hands, devices that can pinpoint
our locations by way of orbiting satellites, and the ability to bank and
shop without leaving our homes.
But none of these innovat... 阅读全帖 |
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M*******c
发帖数: 4371 | 15 到flea market去买吧. 大概$10一个.
curve tracer |
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M*******c
发帖数: 4371 | 16 我还是不明白
你说的开关特性(IV?)是什么? 为什么要和开关时间有关系? |
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c******s
发帖数: 197 | 17 LEM的bandwidth不至于达到1MHz吧，也不想你所说的慢到1ms，为什么不用采样电阻呢？ |
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f*****0
发帖数: 489 | 19 "另外，如果用电压源和电阻，运放，如何做电流源？"
an opamp's based CCS may not be useable here, due to the high minimum Vdd/
Vss an opamp needs to operate.
if you insist on doing that, you are far better of with a 3-pin voltage
reference, like lm317lz or tl431: a couple of capacitors, plut one resistor
+ your variable resistor, and you have created a voltage source whose output
changes with the variable resistor.
if you have to go down the CCS route, you may explore discrete CCS,
especially cascoded jfets: they are inc |
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y*****c
发帖数: 30 | 20 我的毕业课题方向还没有定下来，正在跟老师讨论。
他给了我几个题目
• High voltage packaging for SMART GRID Applications
• Simulate, design and fabricate a high temp gate driver for SiC JFets
/MosFets
• ‘Optimal Designer’ of autonomous, alternative-energy supplied
systems
• Electromagnetic modeling of energy interconnects
• High Temperature operation of heavily doped silicon devices
我自己比较感兴趣的是电源管理。
我的目标是找工作，想利用这个毕业设计做个让自己好找工作的项目。
不拘于以上的东西，老师让我慢慢想，请教下各位有关Analog/Mixed Signal/Power
Electronics的比较热的方向或者说 |
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gr
发帖数: 2958 | 21 我看就2吧，第一个high voltage package要多high啊？
第五也行，感觉比较有前途。3，4感觉太虚了。
JFets |
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g******u
发帖数: 3060 | 22 a few ways.
some rail-rail JFET input opamp to buffer this TTL signal. such as OP482.
If your signal is enable low, try use open collector, again buffer it with
an inverter or so.
if a microcontroller is available, try transmit via some bus signal, or send
another confirmation bit.etc.
some coaxial cable, as aformentioned, but hightly not recommended. |
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w********o
发帖数: 10088 | 23 jfet由于用的是p-n节,channel里有doping,电子迁移率会受影响. mosfet不一定有这个
问题
都是场效应管,光看转移曲线没什么用吧 |
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b*********y
发帖数: 830 | 24 google is ur best friend.
JFET is junction based. it modulates the depletion region of the junction to
control the lateral current. carrier is majority carrier.
used in process where good oxide material is not available, like GaAs.
MOSFET modulates the current by creating an inversion region underneath. it
creats an n channel in a p material in the case of NMOS. |
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H*****l
发帖数: 702 | 25 JFET?BJT?
你找一个集成度高,漏电流小的吧..... |
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c********r
发帖数: 172 | 26
MP0就是一个PMOS管子
shall be able to predict if the ckt could latch up to off-condition. Keep in
mind start up problem is essentially a DC operating point problem, not a
transient issue.I guess you either use transient sim or power supply DC
sweep to verify your design, which is not the right way to do it.
并不是所有的启动都可以完全正确地仿真出来。像这个旧的band-gap电路所有corner的
仿真都显示没有start-up issue，但就这两块芯片在这里出问题了。
另外，当启动电路只有两个DC工作点时（其中一个是零电流状态），你说的是对的，就
是一个工作点问题，只要避开零状态点就可以。当启动电路有多个DC工作点时（你估计
没有遇到过，但我遇到过），就很复杂了。
启动过程必须用瞬态仿真来验... 阅读全帖 |
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c********r
发帖数: 172 | 27
MP0就是一个PMOS管子
shall be able to predict if the ckt could latch up to off-condition. Keep in
mind start up problem is essentially a DC operating point problem, not a
transient issue.I guess you either use transient sim or power supply DC
sweep to verify your design, which is not the right way to do it.
并不是所有的启动都可以完全正确地仿真出来。像这个旧的band-gap电路所有corner的
仿真都显示没有start-up issue，但就这两块芯片在这里出问题了。
另外，当启动电路只有两个DC工作点时（其中一个是零电流状态），你说的是对的，就
是一个工作点问题，只要避开零状态点就可以。当启动电路有多个DC工作点时（你估计
没有遇到过，但我遇到过），就很复杂了。
启动过程必须用瞬态仿真来验... 阅读全帖 |
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s*****2
发帖数: 42 | 28 I have more than 9 years of R&D and product development in semiconductor
devices, especially on high-power and high-temperature device field: MOSFET,
JBS, IGBT, JFET, BJT, MPS, SBD, PiN, GTO
Ask for paper review on semiconductor device modeling, processing and
characterization, especially on power device. |
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m*******e
发帖数: 119 | 29 FET is the general name for all field-effect devices, such as MOSFET, MESFET
, JFET, thin-film transistor, etc. HEMT, also called MODFET, is a sub-group
of FET. All FET devices uses electric field created by gate voltage to
control the conduction level between source and drain (that's why they are
called field effect transistor).
In traditional FET devices, the channel region is doped with impurities.
Carrier mobility is reduced due to scattering by the impurity ions. To
enhance carrier mobility |
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