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UCC27201 problem

Tan Dat Tran
Intellectual 680 points
Other Parts Discussed in Thread: UCC27201

Hi everyone ! I am using UCC27201 to drive MOSFET for a motor driver. I dont know what wrong, It worked but after a while, one of them (3 UCC27201s) got hot and short the circuit and doesnt work anymore. Here my schematic, please take a look and help me out.

8171.Schematic Prints.pdf

  • 0
    TI__Mastermind 25286 points

    to understand what is happening you should check which kind of damage you have on the driver section.

    in particular you have to see which pair of pins results a short ciruit (I bet on SW and GND): depenind on this you can understand where the failure happens an which could be the most attractive root cause....

    based on my experience, I would say normally happens that a load dump on the SW nodes causes spikes/overvoltaged that normally destroy the drivers.

    possible solutions:

    - speed down the transitions with a proper Rgate, to be applied only on HS, not on LS (or at least use very low Rgate for LS)

    - freewheeling diodes are not present, so the current recirculates across body diodes --> adds schottky clamping

    - use snubbers

    - be sure to have enough dead time in the logical PWM generation (I would suggest to use a single IC driver for each couple of FET, or simply look for out motion control solutions at the link http://www.ti.com/paramsearch/docs/parametricsearch.tsp?family=analog&familyId=445&uiTemplateId=NODE_STRY_PGE_T)

    Vincenzo

  • 0 in reply to Vincenzo Pizzolante
    Intellectual 680 points

    Freewheeling diode are now intergated to most of power MOSFET. Sorry for the schematic not showing that.

    I think my problem as you said  is the gate driver overvoltaged because they short the circuit, get heat and die.

    I have use deadtime generator but that did not help. I will try replacing Rgate on LS with a larger value and increase deadtime. 

    Thank you ! I will reply if I success.

  • 0 in reply to Tan Dat Tran
    Prodigy 10 points

    Hi Tan, did you get the issue fixed? What was the critical solution, freewheeling, snubber, or ? I ran into the exact same issue. Having a through-hole prototype board, my biggest concern is relatively long wires and plenty of stray inductance/capacitance. Although I am operating at Hz level (hence no gate-source bleed resistor used as my boost refresh rate is very low), not kHz or MHz, could the fast transition at the gate drive be the source of all evil (driving large 1nF gate capacitance)? Thanks for sharing additional insight! - Bert