Major change of plan

A project log for Scorpion 3.0

Multi tool design for the IIIrd world countries

Marius TaciucMarius Taciuc 08/03/2017 at 01:380 Comments

Major change of mind plan

I was able to put the A3 LTspice simulation into practice and make an actual test circuit.

I measured the efficiency and I can tell you that I’m not very satisfied. The efficiency is between 0.6 and 0.7 depending on the input and output voltages. This is not very satisfying because for the final product I don’t want to use any heatsink. So, like I said, I would have to have more than 0.9 efficiency in order to achieve this.

At this point is very clear to me that I won’t be able to achieve the desired slopes and switching times using a common half bridge for switching the mosfet. One good solution would be to go for a mosfet driver that has integrated half bridges and Trigger Schmidt gates. The problem is that these half bridges are usually supplied at 12V and this means that I will need another intermediate voltage regulator in my schematic.

The  best solution that I’m gonna go for, is using a an integrated Buck circuit. I’m going to use the LM2596. This is the common datasheet recommended schematic that I will have to integrate into my design.

I could use the actual optocoupler PWM system that I have, to drive and control the LM2596. 

Stay tuned for the schematic update.