Continue to Site

Welcome to EDAboard.com

Welcome to our site! EDAboard.com is an international Electronics Discussion Forum focused on EDA software, circuits, schematics, books, theory, papers, asic, pld, 8051, DSP, Network, RF, Analog Design, PCB, Service Manuals... and a whole lot more! To participate you need to register. Registration is free. Click here to register now.

difference between H-bridge based mosfets

Status
Not open for further replies.

m_nader_m

Newbie level 6
Joined
Mar 21, 2008
Messages
12
Helped
0
Reputation
0
Reaction score
0
Trophy points
1,281
Activity points
1,345
difference between H-bridge based mosfet

What is the difference between a H-bridge DC motor driver with N-Channel mosfet and a H-bridge DC motor driver with N-Channel and P-channel mosfet?
Which one is better?
basicmosfethbridge.gif
Bipolar_Stepper_Motor_H-bridge.png
 

Dear Nader
Hi
It is simple , the driver with just Nmosfets will be better , because of similarity between your mosfets , and identical dissipations . and at higher frequencies , we can't use p mosfet and n mosfet in a circuit simply , because of overlap problem but with nmosfets , the dead time creation will be easier .
Best Wishes
Goldsmith
 
the N-channel upper mosfets requires a bootstrap circuitry to effectively drive the MOSFETs.......the RDSon of N-MOS is very less compared to P-MOS......

EA
 
The upper two MOSFETs are configured as high-side switches.

For N-channel MOSFETs, high-side driving is somewhat of a hassle if you don't know about it.

You can turn the high-side P-channel MOSFET on by simply pull the gate to ground (in the circuit shown, where the voltage is 9V).
To turn the high-side N-channel MOSFET on, you need to provide approximately (9+8=)17V. So, you need to either use a charge pump circuit, a gate drive transformer or a high-side driver.

So, it's easier to turn the high-side P-channel MOSFET on/off. However, at higher voltages and currents, it may be more desirable to use N-channel MOSFETs due to lower on-resistances and thus lower losses and greater efficiency. Also, at higher voltages (usually > 20V, but sometimes 30V - the max VGS of the P-channel MOSFET), you can't turn it on simply by grounding the gate. Then, you need level-shifting circuitry.

You can read about high-side driving for N-channel MOSFETs here, where I've explained it a little:

https://www.edaboard.com/threads/182857/#post765226
https://www.edaboard.com/threads/182857/#post766133
https://www.edaboard.com/threads/182857/

Hope this helps.
Tahmid.
 
Status
Not open for further replies.

Similar threads

Part and Inventory Search

Welcome to EDABoard.com

Sponsor

Back
Top