Quad Half Bridge driver board

pedward

I've been working on some stepper research and came up with a board design for a Quad Half Bridge.

Specs:

8A continuous rating per half bridge
.024 ohm 2W current sense chip resistor
48A 8.4 milliohm N-channet mosfets with ultra low 4-8nC gate charge
30V max voltage
IR2302 high side N-channel half bridge driver, runs off +5v
Phoenix contact 5.08mm MKDS series terminal blocks

To answer Phil's question first, the ground pour is only connected to the motor ground, but the logic and motor ground are connected by a single thin trace.

The board is rendered in the DorkbotPDX colors, probably how I'm going to have them fabbed.

T Chap

Under maximum load and voltage will there be heat to deal with? The traces to the terminal blocks look thin. What about putting headers or the terminal in between the sets of mosfets, draw your own fat traces by hand. By putting them in the center of the two rows there is less distance to travel on the board.

Here is an optional motor connection method using a 4 conductor molex header and plug.

http://search.digikey.com/scripts/DkSearch/dksus.dll?x=0&y=0&lang=en&site=us&KeyWords=WM24036-ND

http://search.digikey.com/scripts/DkSearch/dksus.dll?WT.z_header=search_go&lang=en&site=us&keywords=WM18435-ND&x=0&y=0

pedward

I finally got the boards back yesterday and made up a driver board today. The MOSFETs are such low resistance that I don't anticipate needing a heatsink on them. I expect the board could do 4-5 amps per channel without much difficulty, more would be stressing the traces. There is a female header on the bottom so it can stack on top of another board or plug into a breadboard.

tonyp12

My 8 half-bridge quickstart board can handle 2 Amp peak (1.5amp rms) and have current control from 100mA to 1.5 Amp range. (replace 3/4 watt resistors)
Can be put in parallel to double that Amp rating. (waiting for pcbs from China, but will be ready soon)

Is there a need for 4-to-8 Amp stepper drivers?, as I may come up with a second high current version.