h bridge question

http://www.modularcircuits.com/blog/articles/h-bridge-secrets/h-bridges-the-basics/
I've been searching h-bridge for my project and,
I saw this article cause when I search h-bridge in google image, it is first picture that I saw.

Anyway, My question is, do I use 4 negative mosfet, does it working?
Cause as I know, bottom one is nmos and upper one is pmos.
And I make a circuit with all negative mosfet, it seems doesn't work.

Does the link picture is correct picture?

Hi,

pmos = P-CH Mosfet
nmos = N-CH Mosfet

If you used "4 negative mosfet" do you mean 4 N-CH mosfets or nmos.
If they are all the same part number then you haven't used nmos and pmos.

4x N-CH mosfets will only work with logic-level mosfets and if the H-Bridge supply is 5V.

Can you please post a copy of your circuit, in CAD or a picture of a hand drawn circuit in jpg, png?
Including the controller and power supplies and part numbers.

What are you trying to control, what is the load?

Thanks.. Tom.. :slight_smile:

You cannot use high-side N-channel MOSFETs without bootstrap drivers.
See section 5.2.2 of this document: http://www.ti.com/lit/ml/slua618/slua618.pdf

If you use P-channel MOSFETs as high-side switches, you still need a driver if you use a different voltage for your motor than for your logic levels.

Pieter

If you want to use all nFETs, you need H-bridge driver chip like the HIP4081A, which does all the
work of gate driving for you at any supply voltage upto 80V in this case.

You also need a clean 12V supply for the gate driver chip(s).

If you are only handling 10--15V supply, using complementary nFET and pFETs can work,
but you still need some way of driving the pFETs anyway.

Might as well use a driver chip.

A driver chip also means you get high frequency PWM handling as they can drive the gates hard
enough for fast switching.

google "HIP4081A datasheet"

By the way that article wasn't showing complete circuits at all, just the topology of the
switching devices. You always have to sort out the gritty detail of how to drive the devices,
but thats the next level of detail down.