Bygge switchmode, for varm FET

Hej Ulrik

Det kan (sjovt nok) skyldes flere ting:

arbejdscyklen.

SMPS using UC3842 - And related problems [hvis du overvejer xx3842 skal

Citat: "... Mosfet heat is result of normaly two things,

1 on resistance of mosfet

1. insufficient drive volt. ..."

UCC 3800/1/2/3/4/5 BiCMOS CURRENT MODE CONTROL ICs:

Differences Between the UCC3813 and UCC3800 PWM Families:

Citat: "...The UCC3813 family is a lower-cost version of the UCC3800 family of industry standard PWM controllers..."

Andre varianter som er ringere end ucc380x-familien er: UCC38C43 MIC38HC43-1

Does a MOSFET need a gate resistor?:

Citat: "... A gate resistor limits the instantaneous current that is drawn when the FET is turned on. If you are driving a FET directly from a low-current device (microcontroller or logic gate) then gate resistors are recommended. Anywhere from 5 to 100 ohms is fine. They also can be viewed as slew-rate limiting devices for the gate signal, or as devices to eliminate ringing at the gate.

If you are driving the FET from something like a dedicated half bridge driver or similar then they can be eliminated, the drivers are usually meant to be directly connected to the FET. ..."

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Design Tips:

Switching-Mode Power Supply Design Problem List:

Se afsnit 3.1.2 pdf-side 8-9:

Glenn

/CFO

Hej Ulrik

sci.electronics.design

Glenn

PS:

• Knalddygtige folk

hinanden idioter.

• Trolls

• resten...

Nu er du advaret...

Glenn

"Glenn" skrev i en meddelelse news:53cac317$0$302$ snipped-for-privacy@news.sunsite.dk...

skal vist lige ha' en lille basis-kollektor kondensator. :-)

PWM'en er en trekantgenerator lavet over en TL074 og en transistorcomparator.

--
Ulrik Smed 
Aarhus

'bootstrappe' sig til en negativ off puls.

--
Ulrik Smed 
Aarhus

--
Ulrik Smed 
Aarhus

??:

TO-5/PKG SILICON NPN TRANSISTOR 40-VOLT 2.0-AMP 7.0-WATT

...

Cuk-konverter topologien i stedet?:

Citat: "...The point is that many topologies can be more or less made to work for a given application! What is weird but true is that the boostbuck (Cuk) converter works better than all the rest!..."

kommercielt).

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ANALYSIS OF SNUBBING METHODS FOR ISOLATED CUK CONVERTER USED IN ...

Dr. Slobodan Cuk Power Electronics Group, California Institute of Technology

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Feb 1, 2008 Bridgeless PFC Boosts Low-Line Efficiency

Dr. Slobodan Cuk:

Del 1: Jul 1, 2010, True Bridgeless PFC Converter Achieves Over 98% Efficiency,

0.999 Power Factor:

Del 2: Aug 1, 2010, True Bridgeless PFC Converter Achieves Over 98% Efficiency,

0.999 Power Factor: Part 2:

VIP - med diagram: Del 3: Oct 1, 2010, Single-Stage Isolated Bridgeless PFC Converter Achieves Over 98% Efficiency, 0.999 Power Factor:

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Application Characteristics of an Experimental RB-IGBT (Reverse Blocking IGBT) Module:

A High Efficiency Indirect Matrix Converter Utilizing RB-IGBTs:

Glenn

solcellernes plus (3 celler i serie, 180V ind, loaded). Der brugte jeg nogle

--
Ulrik Smed 
Aarhus

On 20/07/14 08.56, Ulrik Smed wrote: ...

in stock

packaging (alt andet end reel) fx: bulk Cut tape tray tube

Valgt min. Vds 500V og op.

Valgt fra min til max. ca 200mOhm

Valgt C input fra min til max. ca 1300 pF

36 fund

Citat: "...

600V 18A (Tc) Gate Charge (Qg) @ Vgs 29nC @ 10V Input Capacitance (Ciss) @ Vds 1060pF @ 100V ..."

Citat: "... These devices are N-channel Power MOSFETs developed using a new generation of MDmeshTM technology: MDmesh II PlusTM low Qg. These revolutionary Power MOSFETs associate a vertical structure to the company's strip layout to yield one of the world's lowest on-resistance and gate charge. They are therefore suitable for the most demanding high efficiency converters. ...

Crss 2,2pF ..."

Jeg fandt fx:

PS: Det var ikke den billigste, men det var fra et firma jeg kendte.

-

Den "billigste" var:

AOTF29S50L:

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En anden:

STF31N65M5:

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Dioder

in stock

packaging (alt andet end reel) fx: bulk Cut tape tray tube

Voltage fx

600-1200V

Current fx

5-10A

66 fund

sorter efter pris (unit price)

PS: Du ved hvis du har sorteret forkert, da den dyreste koster ca.

4000kr :-)

Den billigste koster:

13kr Silicon Carbide Schottky 1200V (1.2kV) 5.9A No Recovery Time > 500mA (Io) [!] Reverse Recovery Time (trr) 0ns Datablad: Citat: "... Features

• 1.2kV Schottky Rectifier

• Zero Reverse Recovery Current

• High-Frequency Operation

• Temperature-Independent Switching

• Extremely Fast Switching

Benefits

• Replace Bipolar with Unipolar Rectifiers

• Essentially No Switching Losses

• Higher Efficiency

• Reduction of Heat Sink Requirements

• Parallel Devices Without Thermal Runaway ..."

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SiC MOSFETs (SiCFET):

(lidt falske med)

Der er 16 fund.

Et lille stykke nede er der en med 156mOhm og 650V:

SCT2120AFC:

650V 29A (Tc) 156 mOhm @ 10A, 18V 61nC @ 18V 1200pF @ 500V

Datablad findes via google:

"... Crss 13pF ved 200V+ ..."

Hvorfor SiC?:

Sep 1, 2007 Reduce Circuit Zapping From Cosmic Radiation:

Citat: "... About 90% of high-energy particles at ground level are neutrons. ... For example, the wide bandgap of silicon carbide makes it much more radiation hardened than conventional silicon. Diodes are also less susceptible to SEB than MOSFETs and IGBTs, but they are still susceptible. ... Like semiconductor technology, the applied voltage stress has a significant effect on the SEB failure rate. Increasing the applied voltage greatly increases the probability of SEB failures. Conversely, decreasing the applied voltage greatly increases reliability, as will be shown. ..."

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Omtale:

Jun. 19, 2013, SiC MOSFETs Enable Next-Generation Solar Inverters

High-Temperature 1200 V/10 A SiC MOSFET

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Jul. 3, 2013, eGaN FET ? Silicon Power Shoot Out: A Retrospective When a new technology is introduced, it is not reasonable to think that engineers will intuitively know how to effectively and efficiently take advantage of the performance enhancements that the new technology offers ? there is always a learning curve. This is being borne out in the case of the rapidly emerging technology of high performance gallium nitride transistors.

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May 1, 2007 A New Way to Model Current-Mode Control

"... This article aims to demystify current-mode control, and cut through the myths and misconceptions of its operation. ..." Jun 1, 2007 A New Way to Model Current-Mode Control

Aug 1, 2007 Stacked-Ceramic Caps Brave High Temperatures

X9U, X8R

Glenn

Mere om SiC:

Sep 1, 2008 Silicon Carbide MOSFETs Challenge IGBTs

Citat: "... SiC also offers a substantially reduced on-resistance variation over its

range of 20%, compared with 200% to 300% for Si. The SiC MOSFET die is

plastic package. ..."

25 August, 2004, BBC News: Door open for silicon replacement: Citat: "... Previous research has already shown that even at red-hot temperatures as high as 650C (1,202F), silicon carbide devices can function unperturbed and without the need for cooling. ... One exciting application for silicon carbide could be in deep-space missions, where nuclear power would be needed for the craft. Radiation-hardened silicon carbide devices would reduce the shielding needed to protect reactor control electronics ..."

Oct 28, 2011, powerelectronics.com: SiC ?Super? Junction Transistors Deliver High Temp Performance:

Citat: "... GeneSiC?s SiC-based 1200 V/220 m? Super Junction Transistors (SJTs)

switching transitions (< 15 ns) ...

..."

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Supplerende om smps generelt:

Jul 1, 2008, No Heatsink Needed for 200-W Buck-Boost Supply:

Glenn

mit bud at din gate driver er for svag.

en samlet gate ladning af 85nC. Det vil sige for at flytte de 85nC i

Kan den det?

Hilsen Klaus

-- Ulrik Smed Aarhus

"Klaus Bahner" skrev i en meddelelse news:53cbf868$0$297$ snipped-for-privacy@news.sunsite.dk...

Det kan den godt, driveren er et lille push-pull trin med en 2 amperes PNP i

kortere switch-tid og mindre ringnings-'kaos' efter skiftet. Men stadig ikke

-- Ulrik Smed Aarhus

"Glenn" skrev i en meddelelse news:53cb7afa$0$298$ snipped-for-privacy@news.sunsite.dk...

fra gamle PC-forsyninger jeg bruger til det her. :-) Det er bare et legeprojekt til mine have-solceller, ikke noget kommercielt.

--
Ulrik Smed 
Aarhus

Hilsen Klaus

Ulrik Smed skriver:

Klaus

-- Modelbane Europas hjemmeside:

Min egen hjemmeside: Forum om modeltog og tog i 1:1:

giver det ikke ret megen forskel med og uden gatemodstand, det er mest en

--
Ulrik Smed 
Aarhus

Det er jo bare en chargepump med udglatningsspoler. ;-)

Jeg har haft lidt lyst til at lave en buck/boost med 2 FET'er og en spole.

--
Ulrik Smed 
Aarhus