I need a one-button on/off toggle power latch to connect/disconnect a 36V battery to two VESC-controlled 500W motors with regenerative braking.
Most of the designs I found for soft latching circuits make use of a high-side P-channel MOSFET which have a too high On-resistance for my use-case. Also, I didn't found a design which blocks the generated power from the motor on off-state, due to the latch feedback and/or body diode.
So I tried to design a circuit with the following features:
- N-MOSFETs for low Rds_on because of high currents (around 30A)
- Bi-directional switching to account for the load/generator states of a motor
- Separate latching feedback
- Fully analog, no microcontroller
- One-button on/off with default state off
I came up with the design below. It seems to work, but I'm not sure why the current in the generative state is halved during button press when switching off. I'm also not sure about the crappy motor modeling...
Do you think this would work in reality? Any hints or tips for improvements?