Yes .. if he manages soldering part.

 

Yes .. if he manages soldering part.

He needs to be quick - especially if the oscillations kill it the first time it is switched on!

 

each gate is basically a capacitor... for AON6512 that is 3.5nF.... and if you have 5 of them in parallel, that would add up to 17.5nF. for IRFH7440 it is 4.7nF per mosfet or 23.5nF for group of five. this means RC time constant on the order of 17-25ms.

when you are turning mosfets on, they gate voltage is rising gradually as the capacitors are charging through 1Mohm resistor. discharge is quicker since this is done through transistor. you need to be aware of charge/discharge time as this affects losses. transistor that turns on/off slowly gets a lot hotter... normally one would see much lower resistor value there. this is normally only the issue if switching is frequent (SMPS, PWM...).

Switching isn't frequent. Think like an on off switch, but instead of a mechanical switch, it uses MOSFETs and the circuit above to drive them according to hall sensor and battery voltage), it is used to switch the rest of the circuit. 150A is the max current and it doesn't react the full current at startup. At startup, current consumption is less than a few amps. It reaches high currents only when we command it to do so.

 

Do you have oscilloscope? I want to see the on & off edges as the MOSFETS work. Several of us have worried about oscillations. There are things in the schematic that I worry about.

Yeah I have an oscilloscope and I've tried to measure what's happening during on/off stages, Vds and Vgs. I haven't taken any photos when I captured it, but I remember that there were no harmful voltages outside the datasheet limits for Vds and Vgs. Only suspicious information which was interesting was: There is a moment just before Vds starts to fall to zero, where current drawn is interestingly high. Vds was near the battery voltage but drain current was instantaneously high. Probably it is the miller region. But even at that suspicious moment, it wasn't out of SOA.

 

Only suspicious information which was interesting was: There is a moment just before Vds starts to fall to zero, where current drawn is interestingly high. Vds was near the battery voltage but drain current was instantaneously high. Probably it is the miller region. But even at that suspicious moment, it wasn't out of SOA.

The SOA graph gives 10A per device at Vds=12V.