For my application, I am using 4S10P Li-ion battery (with NXP's RDDRONE-BMS772) to power the following load:
- 8 ESCs to control thrusters
- 1 Raspberry Pi with hat to control ROV (powered from 5V buck converter).
- 1 high power LED
For my system, I used 4 n-channel MOSFETs TPW1R005PL controlled by LM9061M gate driver as a high-side switch that is capable of running more than 120A continuously, the switch is only in On or Off state and has no switching characteristic. The schematics is as follows:
In which, D2 is TVS diode SMBJ18A clamp at 18V, D1 (at output side) is flyback diode to prevent back emf from the ECSs.
I am able to run the load at 120-150A without any problem. However, I have encountered transient voltage upon turn on the circuit in quick succession (turn on and off and on quickly) and ended up fried multiple BEC. At input side:
I suspect that it is caused by switching effect and inductive load on the circuit, I have tried adding extra TVS diode parallel to the flyback diode, but it cannot suppress the output voltage. What is the recommendation for this case? should I put an RCD snubber across Drain and Source of the MOSFETs to suppress this transient voltage?
Edit 1: I have tested my system with loads connected (thrusters connected to ESCs, and UBEC to power dummy resistor load) and without load connected to the output and received transient voltage for both scenarios.
Edit 2: Input side's signal attached below output signal