How's normally will use 2 Mosfet with PWM (High Side and Low Side) instead
of using one Mosfet.

On Mon, 1 Sep 2003 19:08:48 +0800, "EE-MAN"
wrote:

How's normally will use 2 Mosfet with PWM (High Side and Low Side) instead
of using one Mosfet.

Did you mean how does one use 2 MOSFETS in a PWM configuration?

That works if you have plus and minus supply rails and reference the
load to ground, otherwise you need a four MOSFET bridge and can drive
the load bi-directionally. (speaker in and out or motor in two
directions, or other AC application)

Your question is unclear.


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I means in DC-DC conversion......

For examples....there are one PWM with 2 MOSFET in VGA Card power circuit
(12V to 2.5V conversion). What's the advantanges of using 2 MOSFETs ?


"default" wrote in message
...
On Mon, 1 Sep 2003 19:08:48 +0800, "EE-MAN"
wrote:

How's normally will use 2 Mosfet with PWM (High Side and Low Side)
instead
of using one Mosfet.

Did you mean how does one use 2 MOSFETS in a PWM configuration?

That works if you have plus and minus supply rails and reference the
load to ground, otherwise you need a four MOSFET bridge and can drive
the load bi-directionally. (speaker in and out or motor in two
directions, or other AC application)

Your question is unclear.


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On Mon, 1 Sep 2003 22:25:23 +0800, "EE-MAN"
wrote:

I means in DC-DC conversion......

For examples....there are one PWM with 2 MOSFET in VGA Card power circuit
(12V to 2.5V conversion). What's the advantanges of using 2 MOSFETs ?

If you mean two mosfets in parallel?

Mosfets are usually specified with their "on" resistance - lower is
better. Two mosfets in parallel will have half the resistance of a
single mosfet of the same type. Less resistance means less power lost
when the fet is turned on. The two mosfets can be cheaper than one of
a lower resistance.

Unlike bipolar transistors, mosfet gain goes down as they heat up.
That means that one device doesn't try to hog all the current when
they are in parallel the way bipolars do. If one mosfet heats up it
carries less current and the other mosfet automatically shares the
load. The reason for running them in parallel . . .

Kinda hard to figure out what you are describing with no schematic in
front of me. How are the devices configured?


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