BJT or Logic Mosfet or normal Mosfet - half-bridge driver for BLDC Motor Control

Thread Starter


Joined Aug 24, 2011
Dear all

I have been building the half-bridge driver for BLDC Motor. I now have three options, BJT Method, Logic Mosfet(5V) with Driver IC and P&N MOSFETs.

I have chosen Mosfet(5V) with Driver IC as my solution, but I wasn't sure about my decision.

The reason I rejected BJT is that it is a current-driven device rather than voltage-driven mosfets, and it is less efficient compared to mosfet.

For PMOSFET as high-side and NMOSFET as low side method, I found out online that PMOSFET is not that good.

Since cost, efficiency, reliability are factors of my design, I chose mosfets with driver, but it seems like that my teacher was not that impressed by my solution. Could anyone tell me is there something wrong with my final "mosfet with driver" solution? Is it because of the cost of driver ic chip, or something else?

Much appreciated,


Joined Feb 12, 2009
Your teacher might not be impressed because you seem to have "guessed". Might be better if you weigh up the options in a more systematic way.

Cost? Component count? Efficiency? Reliability? Board space? Etc...