Mosfet heating Up in DC DC converter

[praveen]

Hello,
I have a problem in power supply which i have designed. I have
designed a dual supply of 3.3V and 5.4V from 30 V using semtech
SC2442H DC DC converter and Infineon BS0604NS2 Mosfet.
The problem is that mosfet is getting heated up a lot, it goes to
about 100 C.
I have calculated the power, it turn to be 0.72 W and the Mosfet can
handle upto 2 W. Can some one point why is the mosfet getting
heated???Because of this the inductor and capacitor near it is also
getting heated up.
DC DC converter operating frequency is 250 KHz.

Thanks and regards
Praveen

 

[Nospam]

"praveen" <praveenkumar1979@rediffmail.com> wrote in message
news:ff8a3afb.0412220033.2f92b685@posting.google.com...

Hello,
I have a problem in power supply which i have designed. I have
designed a dual supply of 3.3V and 5.4V from 30 V using semtech
SC2442H DC DC converter and Infineon BS0604NS2 Mosfet.
The problem is that mosfet is getting heated up a lot, it goes to
about 100 C.
I have calculated the power, it turn to be 0.72 W and the Mosfet can
handle upto 2 W. Can some one point why is the mosfet getting
heated???Because of this the inductor and capacitor near it is also
getting heated up.
DC DC converter operating frequency is 250 KHz.

Thanks and regards
Praveen

And the connection with Satellite's and GPS is ?

 

[Rheilly Phoull]

"Nospam" <nospam@please.co.uk> wrote in message
news:41c9354c$0$401$afc38c87@news.easynet.co.uk...

"praveen" <praveenkumar1979@rediffmail.com> wrote in message
news:ff8a3afb.0412220033.2f92b685@posting.google.com...
Hello,
I have a problem in power supply which i have designed. I have
designed a dual supply of 3.3V and 5.4V from 30 V using semtech
SC2442H DC DC converter and Infineon BS0604NS2 Mosfet.
The problem is that mosfet is getting heated up a lot, it goes to
about 100 C.
I have calculated the power, it turn to be 0.72 W and the Mosfet can
handle upto 2 W. Can some one point why is the mosfet getting
heated???Because of this the inductor and capacitor near it is also
getting heated up.
DC DC converter operating frequency is 250 KHz.

Thanks and regards
Praveen

And the connection with Satellite's and GPS is ?


It may have escaped your attention that sometime things are crossposted, for

example I am reading your post in the NG 'sci.electronics.design', which
would seem to be appropriate ??

--
Regards ..... Rheilly Phoull

 

[Tony Williams]

In article <ff8a3afb.0412220033.2f92b685@posting.google.com>,
praveen <praveenkumar1979@rediffmail.com> wrote:

I have a problem in power supply which i have designed. I have
designed a dual supply of 3.3V and 5.4V from 30 V using semtech
SC2442H DC DC converter and Infineon BS0604NS2 Mosfet. The
problem is that mosfet is getting heated up a lot, it goes to
about 100 C. I have calculated the power, it turn to be 0.72 W
and the Mosfet can handle upto 2 W. Can some one point why is the
mosfet getting heated???Because of this the inductor and
capacitor near it is also getting heated up. DC DC converter
operating frequency is 250 KHz.

Did your calculations allow for the switching losses?

I've just been simulating a simple 1300 Hz PWM switch
where the simulation shows that the MOSFETs dissipate
about 2.5W each. But only 1.5W of that is the "dc"
loss, another 1W comes from the switching losses. In
fact the simulation shows a peak of 160 V*I during
each on/off edge.

--
Tony Williams.

 

[Rene Tschaggelar]

praveen wrote:

Hello,
I have a problem in power supply which i have designed. I have
designed a dual supply of 3.3V and 5.4V from 30 V using semtech
SC2442H DC DC converter and Infineon BS0604NS2 Mosfet.
The problem is that mosfet is getting heated up a lot, it goes to
about 100 C.
I have calculated the power, it turn to be 0.72 W and the Mosfet can
handle upto 2 W. Can some one point why is the mosfet getting
heated???Because of this the inductor and capacitor near it is also
getting heated up.
DC DC converter operating frequency is 250 KHz.

Multiposted to far too many groups. Reply the SED only.

The new SO8 FETS are indeed specified for 2W.
It is your problem to get rid of the heat though.
To give you an idea, a double layer copper on a pcb
of 1 inch in square gets pretty hot with 1 W.

Rene
--
Ing.Buero R.Tschaggelar - http://www.ibrtses.com
& commercial newsgroups - http://www.talkto.net

 

[clifto]

Nospam wrote:

"praveen" <praveenkumar1979@rediffmail.com> wrote...
I have calculated the power, it turn to be 0.72 W and the Mosfet can
handle upto 2 W. Can some one point why is the mosfet getting
heated???

And the connection with Satellite's and GPS is ?

To the original idiot crossposter:

Get a 13.2V power source such as a car battery. Get a 240 ohm, 1 watt
resistor. Connect the resistor across the power source (0.72 W) and
hold the resistor in your hand for one hour. Come back and report
your findings.

--
The state religion of the USA is atheism, as established by the courts.