Hi

Am slowly progressing on an H Bridge project but want to add some protection across the MOSFETs by sensing if the devices aren't switching on properly and go into overcurrent.

Any bright ideas on a trick to sense the Vdrop across the Drain Source after a small time delay once the gate is triggered to sense if the device is gonig to go into melt down mode.

Am using an IR2110 so will obviously feed back to the shutdown line.

Many thanks

DS

 

i think an electrostatic voltage sensing device followed by a trigger circuit which will trigger a high current depletion mode mos device connected in series with the power supply bus will solve the problem.

 

Just use current sensing resistors in series at the low side FET's
see the 0.1 resistors in the low side drivers RS1 & RS2
http://forum.allaboutcircuits.com/attachment.php?attachmentid=19900&d=1274985981

 

or just use the LMD18200T H-Bridge, it has current sensing built in, and thermal shutdown....

B. Morse